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FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
BRADLEY LAKE
HYDROELECTRIC PROJECT
FEDERAL ENERGY REGULATORY COMMISSION
PROJECT NO. P-8221-000
VOLUME 1
REPORT AND
DESIGN CRITERIA
Prepared By
STONE & WEBSTER ENGINEERING CORPORATION
JULY 1988
TABLE OF CONTENTS
r
TABLE OF CONTENTS
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 1 -REPORT AND DESIGN CRITERIA
PART A -REPORT
PART B -DESIGN CRITERIA
VOLUME 2 -CALCULATIONS
VOLUME 3 -CALCULATIONS
0242R-5049R/CG 1
TABLE OF CONTENTS (Continued)
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 1
REPORT AND DESIGN CRITERIA
PART A -REPORT
1.0 INTRODUCTION
1.1 CONSTRUCTION CONTRACTS
1.2 FINAL SUPPORTING DESIGN REPORTS
1.3 GENERAL INFORMATION REGARDING PROJECT FEATURES
ADDRESSED BY THIS REPORT
2.0 DESIGN INFORMATION
2.1 DESIGN
2.2 DESIGN LOADS
2.3 DESIGN AND ANALYSIS LOADING COMBINATIONS
2. 4 STABILITY REQUIREMENTS
3.0 SUITABILITY ASSESSMENT
3.1 POWERHOUSE
3.2 MIDDLE FORK DIVERSION
3.3 NUKA DIVERSION
3. 4 OTHER AREAS
4.0 GEOTECHNICAL INVESTIGATIONS
5.0 BORROW AREAS AND QUARRY SITES
6.0 DESIGN AND STABILITY ANALYSIS
6.1 GENERAL
6.2 POWERHOUSE, TAILRACE, AND SUBSTATION
6.3 MIDDLE FORK AND NUKA DIVERSIONS
7.0 BASIS FOR SEISMIC LOADING
7.1 GENERAL
7.2 SEISMOTECTONIC SETTING
7.3 SEISMIC DESIGN
8.0 BOARD OF CONSULTANTS
8.1 INDEPENDENT BOARD OF CONSULTANTS
8.2 FERC BOARD OF CONSULTANTS
0242R-5049R/CG 11
APPENDIX A
Exhibit F Plates
TABLE OF CONTENTS (Continued)
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 1
REPORT AND DESIGN CRITERIA
PART A·-REPORT•
DRAWINGS
Title
1 General Plan
7 Civil Construction Excavation at Powerhouse -Plan
8 Civil Construction Excavation at Powerhouse -Elevations
9 90 MW Pelton Powerhouse
11 Middle Fork Diversion, Intake Basin & Upper
Channel -Plan, Profile & Sections
12 Middle Fork Diversion, Stilling Basin &
Lower Channel -Plan, Profile & Sections
14 General Arrangement -Permanent Camp and Powerhouse
16 Powerhouse Substat.ion and Bradley Junction
17 Main One Line Diagram
21 Nuka Diversion, Nuka River Outlet Structure -Plan
22 Nuka Diversion -Details
23 Upper Bradley River Outlet Weir -Plan,
Sections & Details
Powerhouse, General Arrangement -Plan El 15.00'
Powerhouse, General Arrangement -Plan El 21.00 I
Powerhouse, General Arrangement -Plans El 42.00' & El
24
2.S
26
27 Powerhouse, General Arrangement -Longitudinal Section
APPENDIX B ATTACHMENTS
B.l Construction Schedule Contract Dates
0242R-5049R/CG iii
60'-0"
TABLE OF CONTENTS (Continued)
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 1
REPORT AND DESIGN CRITERIA
PART B -DESIGN CRITERIA
1.0 Hydraulic Design Criteria
1. Hydraulic Turbines, Governors and Spherical Valves
2. Tailrace
3. Middle Fork Diversion
4. Nuka Diversion
2.0 Control System Design Criteria
3.0 Mechanical Design Criteria
4.0 Structural Design Criteria
Part A
Part B
General Structural Design Criteria
Part B-6
Part B-7
Part B-8
Special Requirements and Design Criteria for Major
Structures
Powerhouse
Tailrace
Substation
5.0 Architectural Design Criteria
6.0 Geotechnical Design Criteria (Middle Fork and Nuka Diversions)
7.0 Electrical Design Criteria
0242R-5049/CG iv
TABLE OF CONTENTS (Continued)
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 2
CALCULATIONS
STRUCTURAL
Title
WIND LOADS FOR DESIGN CRITERIA
SNOW AND ICE LOADS FOR DESIGN
CRITERIA
SEISMIC DESIGN DATA
POWERHOUSE SEISMIC ANALYSIS METHOD
SPHERICAL VALVE FOUNDATION
POWERHOUSE STABILITY -SUBSTRUCTURE
POWERHOUSE BUILDING -WEST WALL
(LINE E)
GENERATOR SUPPORT BARREL
0242R-5049R/CG v
Calculation
No.
SDC.1
SDC.2
SDC.3
SDC.6
SC-214-6B
SC-212-10A
SC-222-12A
SC-219-36
TABLE OF CONTENTS (Continued)
FINAL SUPPORTING DESIGN REPORT
POWERHOUSE CONSTRUCTION CONTRACT
MIDDLE FORK AND NUKA DIVERSIONS
AND RESERVOIR CLEARING CONTRACT
VOLUME 3
CALCULATIONS
STRUCTURAL
Calculation
Title No.
POWERHOUSE -SPIRAL CASING SC-215-37
COMPUTER ANALYSIS OF POWERHOUSE SUPER-SS-223-7B
STRUCTURE FOR DEAD, LIVE, SNOW, AND
SEISMIC LOADS
MEMBER DESIGN OF POWERHOUSE SUPER-SS-223-7C
STRUCTURE
OVERALL ANALYSIS AND DESIGN OF MAIN SS-223-7D
STEEL FRAMING FOR POWERHOUSE
SUPERSTRUCTURE
GEOTECHNICAL
Calculation
Title No.
POWERHOUSE AREA GROUNDWATER AND UPLIFT G(Ak)-27
PRESSURES
MIDDLE FORK OF BRADLEY RIVER G(D)-103
DIVERSION CHANNEL ALIGNMENT
HYDRAULIC
Title
MIDDLE FORK DIVERSION FLOOD FREQUENCY
MIDDLE FORK BRADLEY RIVER SIMULATED
HYDRO GRAPH ( PMF)
TSUNAMI WAVE FORCES ON THE POWERHOUSE
PROBABILITY THAT COMBINED TIDE AND
TSUNAMI WATER LEVEL EXCEEDS VARIOUS
LEVELS
NUKA DIVERSION CONCEPTUAL HEAD
DELIVERY CURVES
MIDDLE FORK HYDRAULICS
0242R-5049R/CG vi
Calculation
No.
H-030
H-031
H-045
H-052
H-055
H-058
PART A
REPORT
SECTION 1.0
INTRODUCTION
1.0 INTRODUCTION
As part of the documents for the Application for License for the Bradley
Lake Hydroelectric Project, the Applicant issued a "Preliminary Supporting
Design Report." In that document the Applicant stated that a "Final Design
Report" would be submitted to the Commission for review and approval prior
to the award of each construction contract.
1.1 CONSTRUCTION CONTRACTS
There will be · seven major construction contracts awarded for project
facilities. The scheduled dates for the submittal of Final Supporting
Design Reports for each phase to the Commission for approval and the dates
for starting each phase· of construction are shown on Construction Schedule
Contract Dates Appendix B (Attachment B.l). The seven construction
contracts consist of:
First Contract -Site Preparation Contract (completed August 1987)
• Clearing, grubbing and removing overburden in diversion
structure, camp, road, and powerhouse areas
• Rock excavation
• Construction of access road and bridges to permanent facilities
and Martin River borrow area
• Quarry and placing riprap
• Site grading and stockpiling topsoil
• Diversion tunnel excavation
• Placing concrete and reinforcing steel for the intake structure of
the diversion tunnel
• Construction of the temporary and permanent camp facilities
including utilities
• Construction of the airstrip
• Construction of the barge dock including sheet pile cells,
approach roads and local dredging
• Placing rock bolts and slope protection in powerhouse and
di ver.sion tunnel exca'rat ions
0242R-SOSOR/CG 1-1
• Improvement of channel downstream of diversion tunnel outlet
• Installation of communication tower power supply and main· damsi te
power supply cable and install television/phone service microwave
and light fiber optic cables. (Owner installed)
Second Contract -General Civil Construction Contract
• Construction of diversion outlet structure and gate shaft
• Completion of the concrete and steel lining of the diversion tunnel
• Excavation of the power tunnel
• Construction of the power tunnel concrete and steel lining
including intake and vertical gate shaft
• Installation of the power penstock
• Rock excavation for all permanent structures including. tailrace
channel
• Construction of the dam, spillway and cofferdams
• Electrical and mechanical work for the diversion tunnel gate shaft
and fish by-pass facilities
• Electrical and mechanical work for the power tunnel gate shaft
Third Contract -Transmission Line Clearing Contract
-• Clearing of the transmission line right-of-way
• Disposal of vegetative matter
Fourth Contract -Powerhouse Construction Contract
• Construction of the powerhouse including installation of equipment
• Construction of powerhouse substation
Fifth Contract -Transmission Line Construction Contract
• Construction of transmission line
• Construction of Bradley Junction transmission line intertie
0242R-5050R/CG 1-2
Sixth Contract -Middle Fork and Nuka Diversions, and Reservoir Clearing
Contract
• Construction of Nuka Diversion
• Construction of Middle Fork Diversion
• Reservoir Clearing
Seventh Contract -Rehabilitation and Recreational Facilities Construction
Contract
• Rehabilitation Activities
Martin River Borrow
Waterfowl Nesting Area
Campsites, Staging Areas and Concrete Batch Plant Areas
• Recreational facilities
1.2 FINAL SUPPORTING DESIGN REPORTS
The Final Supporting Design Report for the Site Preparation Contract was
submitted by the Applicant in March 1986 and was approved by FERC on
May 20, 1986.
The Final Supporting Design Report for the General Civil Construction
Contract and Exhibit F drawings were submitted by the Applicant in March
1988 and were approved by FERC on June 10, 1988.
The Final Supporting Design Report for the Powerhouse Construction
Contract; and the Middle Fork and Nuka Diversions and Reservoir Clearing
Contract is the third and last remaining Supporting Design Report; and is
submitted by the Applicant to demonstrate that the work proposed under
these Contracts is safe and adequate to fulfill their stated functions.
0242R-5050R/CG 1-3
Final Exhibit F drawings for the Powerhouse Contract, and Middle Fork and
Nuka Diversions and Reservoir Clearing Contract are included herein by the
Applicant for Commission approval .
Unless otherwise noted, all elevations given in this report are based on
Bradley Lake Project Datum.
1.3 GENERAL INFORMATION REGARDING PROJECT FEATURES ADDRESSED
BY THIS REPORT
Refer to Plates 1 and 17 in Appendix A for the General Plan of the Project
and the Main One Line Diagram, respectively.
1. 3.1 Powerhouse
The Bradley Lake, Hydroelectric Project powerhouse has been designed to
house two 45 MW Pelton-type turbines with generators and associated support
equipment and systems.
For Plates depicting the powerhouse, its excavation, etc., see Plates 7, 8,
9, 14, 24, 25, 26, and 27 in Appendix A.
The powerhouse consists of a reinforced concrete substructure founded in
rock and a structural steel superstructure enclosed with insulated siding
and roof. The structure is approximately 80 ft wide by 160 ft long. The
substructure extends from project El -9 at the discharge chamber level to
El +42 at the generator floor level. The superstructure extends from
El +42 to approximately El +85.
The substructure consists of the Generator Floor at El +42, the Turbine
Floor at El +21, and sumps, pits and chambers associated with operation of
the turbine located at lower levels. The Turbine Floor, in addition to
0242R-5050R/CG 1-4
providing access to the turbines/generators, contains the lube oil
processing and storage facilities, the battery room, the emergency diesel
generator and other equipment associated with the plant operation. The
Generator Floor consists of an open 56 ft wide bay serving the two
generators with control equipment, and includes a lay down and Service Bay,
and a 24 ft wide Auxiliary Bay housing the control and service needs of the
powerhouse. The Auxiliary Bay contains support facilities including the
Control (SCADA) Room, plant office, lunch room, locker room, toilets and
the machine shop. The Generator Floor remains clear and unobstructed with
access for a 160 ton bridge cran~ with an auxi 1 iary 25 ton hook. The
bridge crane can run the full length of the powerhouse. Hatches are
provided to access lower levels. The Auxiliary Bay is designed to support a
secondary floor at El +60 which houses HVAC equipment and provides room for
storage.
The powerhouse · substructure and superstructure are designed with the
consideration in mind that a third 45 MW unit may be added to the south
side in the future. Excavation of the rock for the third unit's
substructure is accomplished with the excavation for the first two units to
avoid future blasting near operational units. The excavated area is to. be
backfilled untll the third unit is installed.
1.3.2 Tailrace
The tailrace is a pool downstream of the powerhouse designed to collect
water released from the turbines and to provide a channel to transport that
water away from the powerhouse. The tailrace further acts as a stilling
basin by reducing the turbulent flow of released water before it flows into
Kachemak Bay.
The flow of water from the powerhouse will be channeled into the main flow
path of the tailrace channel by the discharge chamber walls constructed as
part of the. powerhouse substructure. A concrete retaining wall is required
0242R-5050R/CG 1-5
to retain the fill material just north of the powerhouse and west of the
substation. The retaining wall connects with the north end wall of the
powerhouse.
The tailrace will be excavated out of the mudflats inunediately to the west
of the powerhouse. Rock adjacent to the powerhouse will be removed to
provide proper channel alignment. The sides and bot tom of the tailrace
basin will be riprapped for protection from scouring. The tailrace is
presently sized for two units.
1. 3. 3 Substation
The substation consists of a Compact Gas Insulated Substation (CGIS),
transformers and line terminations on the powerhouse from the transmission
system. Refer to Plate 16 in Appendix A. The substation is adjacent to
and tied into the north wall of the powerhouse and as such may be
considered an extension to the powerhouse.
The CGIS is housed in a reinforced concrete extension of the powerhouse,
consisting of a 115 kV, 4 breaker ring bus as described in the Project
Electrical' Design Criteria herein. The substation area serves as the line
terminals for two power transmission circuits which connect the powerhouse
to the local utility transmission system.
Three main unit power transformers ( 115 kV) are to be mounted on concrete
pads, located adjacent to the north wall of the extension housing the CGIS
system. The transformers are provided with separation walls and
containment basins filled with crushed rock.
1. 3.4 Middle Fork Diversion
The Middle Fork Diversion is located approximately one mile north of
Bradley Lake in an adjacent drainage at elevation 2160 on the Middle Fork
0242R-5050R/CG 1-6
Tributary of the Bradley River. See Plates 11 and 12 in Appendix A. The
Diversion consists of a small intake basin and two reaches of open. channel
approximately 770 feet and 480 feet long, separated by a stilling basin
which is located in a natural bog area, all of which will be established by
excavation. The Diversion will convey water from the Middle Fork of the
I
Bradley River to Marmot Creek, a tributary to Bradley Lake, and will
operate in all seasons.
1. 3. 5 Nuka Diversion
Glacial melt forms a pond called Nuka Pool at the terminus of the Nuka
Glacier. Nuka Pool lies on t:r.e divide between two drainages, discharging
water both into the Upper Bradley River and into the Nuka River. Water
discharged into the Upper Bradley River flows to Bradley Lake and that
which is discharged into the Nuka River flows to the Kenai Fjords National
Park.
The purpose of the Nuka Diversion improvements (see Plates 21, 22, and 23
in Appe_ndix A) is to cause the glacial melt ·water flowing through the Nuka
Pool to flow into the Upper Bradley River, except for an initial increment
of flow which must be provided to the Nuka River in accordance with the
June 1986 Contract between the Alaska Power Authority and the U.S.
Department of the Interior. Per this Contract, the design must assure that
the first 5 cfs of available flow goes to the Nuka River. Flow in excess
of 5 cfs will be diverted to the Upper Bradley River.
1.3.6 Reservoir Clearing
The Bradley Lake Hydroelectric Project Vegetative Clearing Plan was
submitted by the Applicant to FERC in March 1986 and later approved by
FERC. The information contained in the Plan will not be reproduced here,
but the interested reader is referred to the detailed reservoir clearing
0242R-5050R/CG 1-7
description therein. The reservoir clearing scheme remains valid with the
exception that woody shrubs occuring on the Kachemak Delta and Upper
Bradley River Delta below elevation 1140 will not be cleared. The purpose
of this change is to prevent, during reservoir filling, the mobilization of
slash which would remain following the clearing operations. This change
is also consistent with the original intent of the Vegetative Clearing Plan
to remove only the spruce trees and to leave intact the woody shrubs
growing on the steep hillsides within the reservoir inundation zone.
0242R-5050R/CG 1-8
SECTION 2.0
DESIGN INFORMATION
2.0 DESIGN INFORMATION
2.1 DESIGN
The following design data are furnished to indicate to the Commission staff
the applicable codes, guides, regulations, and standards which are utilized
in the engineering and design documents required for the Bradley Lake
Hydroelectric Project. Attached to this report are the Design Criteria
that are the basis of the design of the improvements listed below:
• Powerhouse
• Tailrace
• Substation
• Middle Fork Diversion
• Nuka Diversion
2.1.1 Codes, Guides and Regulations
Where specific standards and design criteria are not covered in these
design data, the latest edition of the following codes and standards will
apply:
2.1.1.1 General
ANSI A58.1 Minimum Design Loads for Buildings and Other Structures;
American National Standards Institute
UBC Uniform Building Code; International Conference of Building
Officials
AAC Alaska Administrative Code, Section 13AAC50 (incorporates UBC
provisions for Alaska Building Code)
0242R-5051R/CG 2-1
OSHA-AK
OSHA-US
General Safety Code, Vol. I, II, and III, Occupational Safety
and Health Standards, Alaska Department of Labor, Division of
Occupational Safety and Health, 1973 and as amended in 1983
and the Construction Code, 1974 and as amended in 1982
u.s. Department of
Administration, OSHA
(29 CFR 1910), and
Labor Occupational Safety
2206 General Industry
OSHA 2207 Construction
and Health
Standards
Industry
(29 CFR 1926/1910), as supplement to the State of Alaska's
General Safety Code
UL-FRD Fire Resistance Directory Underwriters Laboratory
2.1.1.2 Concrete
ACI 207.2R
ACI 211.1
ACI 301
ACI 302.1R
ACI 306
ACI 315
ACI 318
0242R-5051R/CG
Effect of Restraint, Volume Change, and Reinforcement on
Cracking of Massive Concrete; American Concrete Institute
Standard Practice for Selecting Proportions for Normal, Heavy
Weight, and Mass Concrete; American Concrete Institute
Specifications for Structural
American Concrete Institute
Concrete for Buildings;
Guide to Concrete Floor and Slab Construction
Cold Weather Concreting; American Concrete Institute
Manual of Standard Practice for Detailing Reinforced Concrete
Structures; American Concrete Institute
Building Code Requirements for Reinforced Concrete and
Commentary; American Concrete Institute
2-2
ACI 336.2R
ACI 347
ASTM C33
ASTM Cl50
CRD-Cl19
Suggested Design Procedures for Combined Footings and Mats;
American Concrete Institute
Recommended Practice for Concrete Formwork; American Concrete
Institute
Specification for Concrete Aggregates; American Society for
Testing and Materials
Specification for Portland Cement; American Society for
Testing and Materials
Method of Test for Flat and Elongated Particles in Coarse
Aggregate; U.S. Army, Corps of Engineers
CRSI CRSI Handbook; Concrete Reinforcing Steel Institute
2.1.1.3 Steel
AISC
AISC.
AISC
Manual of Steel Construction; American Institute of Steel
Construction, Inc., 8th Edition
Specification for the Design Fabrication and Erection of
Structural Steel for Buildings with Commentary; American
Institute of Steel Construction
Codes of Standard Practice for Steel Buildings and Bridges
with Commentary; American Institute of Steel Construction
AISC Specification for Structural Joints Using ASTM A325 and A490
Bolts
0242R-5051R/CG 2-3
AISI
ASME VIII
ASTM
AWS Dl.l
AWS D1.4
AWWA C200
AWWA C206
AWWA C207
AWWA C208
AWWA 0100
AWWA 0102
AWWA Mll
0242R-5051R/CG
Specifications for the Design of Cold-Form Steel Structural
Members with Commentary; American Iron and Steel Institute
Boiler and Pressure Vessel Code; American Society of
Mechanical Engineers
Various Standards, American Society for Testing and Materials
Structural Welding Code; American Welding Society
Reinforcing Steel Welding Code; American Welding Society
Steel Water Pipe 6 Inches and Larger; American Water Works
Associ at ion
Standard for Field Welding of Steel Water Pipe; American
Water Works Association
Standard for Steel Pipe Flanges for Waterworks Services -
Sizes 4 in. through 144 in.; American Water Works Association
Standard for Dimensions for Steel Water Pipe Fittings;
American Water Works Association
Standard for Welded Steel Tanks for Water Storage; American
Water Works Association
Standard for Painting Steel Water-Storage Tanks; American
Water Works Association
Steel Pipe Design and Installation; American Water Works
Association
2-4
2.1.1.4 Design Guides
SEAOC
ATC 3-06
NFPA
DOT/PF
SJI
Recommended Lateral Force Requirements and Commentary,
Structural Engineers Association of California
Tentative Provisions for the Development of Seismic
Regulations for Buildings; Applied Technology Council
National Fire Protection Association
Alaska Department of Transportation and Public Facilities,
Design Standards for Buildings
Standard Specifications and Load Tables Steel Joist Institute
(SJI)
Additional design guides and references are listed in the Design Criteria
which are part of this Supporting Design Report.
0242R-5051R/CG 2-5
2.2 DESIGN LOADS
The following design loads are being considered with the loading
combinations described in Section 2.3, Design and Analysis Loading
Combinations.
2.2.1 Dead Loads
Mass Concrete
Reinforced Concrete
Steel
Water
Ice
Salt Water
Silt -Vertical
-Horizontal
Backfill
-Dry
-Moist
-Submerged
Sound Rock
2.2.2 Live Loads
Generator Floor
Service Bay Floor
Turbine Floor
Tailrace Deck
Spherical Valve & Runner
Gallery
145
150
490
62.4
56
64
120
85
120
135
85
170
300
800
300
150
300
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 3
lbs/ft 2
lbs/ft 2
lbs/ft 2
lbs/ft 2
lbs/ft 2
Information about the application of live loads and further tabulation of
loads used in design may be found in the General Structural Design Criteria
included in this Supporting Design Report.
0242R-5051R/CG 2-6
2.2.3 Backfill Loads
The lateral earth pressure against vertical faces of structures with
cohesionless horizontal backfill is computed using the equivalent fluid
pressures calculated from:
p = KwH
Where:
p = unit pressure
K = pressure coefficient
w = unit weight of fill
H = height of fill
For structures free to deflect or rotate about the base the pressure
coefficient is computed from Rankine's theory, using the following equation:
2 K = tan (45-0/2) a
Where 0 =angle of internal friction (degrees).
For structures restrained from bending or rotation, the at-rest pressure
coefficient is used:
K = 1 -sin 0
0
For inclined walls, sloping backfill, soil wall friction, compaction
induced pressures and surcharge pressures refer to Geotechnical Technical
Guidelines GTG-6.15-1, Determination of Lateral Pressures on Buried
Structures in Granular Soils, for applicable equations.
Where vehicular traffic can run adjacent to the structure, a surcharge
loading of 300 lbs/ft 2 is applied.
0242R-5051R/CG 2-7
2.2.4 Snow and Ice Loads
Roofs, decks, and structural features which will carry snow or ice loads
are designed in accordance with the technical document ETL 1110-3-317, U.S.
Dept. of Army, with additional provisions where more severe icing is
considered likely.
2.2.5 Equipment Loads
Equipment loads are evaluated for empty weight (dead weight of equipment),
operating weight (full contents), and operational loadings (torques, etc).
Equipment weights for major equipment used in the analysis are given in
Table 3 of the General Structurai Design Criteria.
2.2.6 Hydraulic Loads
All structures are designed for full lateral water pressures, including
hydrodynamic and uplift forces, where applicable. Tsunami forces were
considered at the west wall of the Powerhouse and its support elements.
Refer to Attachment C of the Powerhouse Structural Design Criteria and to
Calculation SC-222-12A, Powerhouse Building -West Wall (Line E), for
further information.
2.2.7 Uplift
Uplift is assumed to act over 100 percent of the affected area of the
structure.
Uplift pressure is equivalent to the full water pressure acting on a
foundation or structure where no head differential exists across the
structure. The foundations and structures are analyzed for flotation, if
applicable.
0242R-5051R/CG 2-8
2.2.8 Seismic Loads
The Bradley Lake Project is located in a seismically active region.
Structures and equipment are subjected to seismic event loads in accordance
with their classifications as non-critical, critical, or hazardous.
Detailed information regarding seismic loading is provided in Section 4.8
of the General Structural Design Criteria and in the criteria for
individual project facilities. Refer also to Section 7.0 of this present
report for information on the basis for seismic loading.
For the Operational Basis Event (OBE), having a peak horizontal ground
acceleration of up to O.lg, project features are designed for no
significant damage and a downtime of a few hours. For the Design Basis
Event (DBE), having a peak horizontal ground acceleration of O.lg to 0.3Sg,
design permits some architectural damage to the Powerhouse and Substation
and minor damage to turbine/generator/governor parts. Downtime following
the DBE is up to 6 months. For the Maximum Credible Event (MCE), having a
peak horizontal ground acceleration of 0.3Sg to 0.7Sg, design permits
limited structural damage and -significant architectural damage to the
Powerhouse and Substation, but no structural collapse. The MCE may also
cause major turbine/generator/governor damage and result in possible
downtime of more than 6 months.
The Middle Fork and Nuka Diversions are considered non-critical and are not
designed to withstand seismic loadings.
2.2.9 Temperature and Thermal Loads
Expansion and contraction resulting from temperature changes, moisture
changes, creep in component materials, and movement resulting from
differential settlement are combined with other forces and loadings for
maximum effects. The minimum design temperature is -30°F and the maximum
design temperature is +85°F.
0242R-5051R/CG 2-9
2.2.10 Wind and Wind Related Loads
Wind loads developed for the Bradley Lake project are based on the 1985
Uniform Building Code formula for wind pressure:
where:
p =
p = C C q I e q s (UBC Chap. 23, 11-1)
design wind pressure
c = combined height, exposure and gust factor coefficient as e
given in UBC Table No. 23-G
c = pressure coefficient for the structure or portion of q
structure under consideration as given in UBC Table
No. 23-H
qs = wind stagnation pressure at the standard height of 30 ft
as set forth in UBC Table 23-F
I = importance factor as set forth in UBC Section 23ll(h)
Wind Load Application
Wind loads are applied orthogonally to buildings and structures in only one
direction at a time. Wind loads are not combined with earthquake loadings;
however, they are applied in combination with snow loads, with snow loads
reduced to account for removal by wind action.
0242R-5051R/CG 2-10
2.2.11 Other Loads
The following loads and load allowances are also included in the design:
• Pipe and Cable Tray Load Allowances
• Roof Girder Load Allowance
• Column Load Allowance
• Bracing Load
• Temporary Roof Loads
• Crane Impact Allowance
• Hoist Trolley Loads
• Truck Loads
• Vibrational Loads
• Construction Loads
2.3 DESIGN AND ANALYSIS LOADING COMBINATIONS
Load combinations for specific structures are identified in the pertinent
design criteria. Should an area not be identified, and in the absence of
other instructions, the following loading combinations are observed:
2.3.1 For Dead Load, Live Load, Wind; Seismic and Snow.
D + L
D + L + w
D + L + E
D + L + s
D + L + w + o.sos
D + L + o.sow + s
D + L + E + O.SOS
0242R-5051R/CG 2-11
2.3.2
A 1/3 increase in allowable stresses may be used for combinations
including wind per the applicable codes; allowable stresses for
seismic conditions shall be as defined in the General Structural
Design Criteria.
For Equipment Supports
M (empty) + W or E
M (operating) + L
M (operating) + L + (W or E)
M (flooded or testing load)
Critical load combinations may vary for specific pieces of
equipment.
2.4 STABILITY REQUIREMENTS
2. 4.1 Powerhouse
The Powerhouse is analyzed for stability against overturning, sliding and
floatation (see calculation SC-212-lOA, Powerhouse Stability -Substruc-
ture) for the following load cases:
CASE No. CLASS CASE NAME
1 Normal Operating
2 Unusual .35g seismic
0242R-5051R/CG
LOADING COMBINATION
-Substructure, superstructure, and
installed equipment weights
-Running or standby turbine
operating forces
-Tide at MHW El +4.0'
-Horizontal and uplift fluid pressure
-Fluid at El +4.0' in the
discharge chamber
-Fluid at El +11.5' in the clean
water sump
-Same as operating case except:
- A 0.3Sg seismic event (horizontal)
2-12
CASE No. CLASS CASE NAME
3
4
5
6
7
8
9
Unusual Storm tide
Unusual Servicing
Unusual Construction
Extreme ·. 75g seismic
Extreme Sump empty
Extreme Construction
with seismic
Extreme 0.50g Vertical
Seismic
LOADING COMBINATION
-Same as operating case except:
-Tide at Storm tide El +13.4'
-Fluid at El +5.0' in the
discharge chamber
-Same as operating case except:
-No operating turbine forces
(spherical valve closed)
-Tide at Highest tide El +11.4'
-No fluid in discharge chamber
-Stage I concrete weight only
-Tide at Highest tide El +11.4'
-Horizontal and uplift fluid pressures
·_ No tailwater pressure
-No fluid in discharge chamber
-No fluid in clean water sump
Same as operating case except:
-A 0.75 seismic event (horizontal)
-Same as operating case except:
-Tide at Highest tide El +11.4'
-No fluid in clean water sump
-Same as construction case except:
-A O.lOg seismic event (horizontal)
-Same as operating case except:
- A 0.50g vertical seismic event
The factors of safety used for the above cases depend on the class and are
as follows:
CLASSIFICATION
NORMAL UNUSUAL EXTREME
F.S. Floatation 1.5 1.2 1.05
F.S. Overturning 1.5 1.2 1.05
F.S. Sliding 3.0 1.5 1.05
For the unusual and extreme classes, 20 psi tension is allowed before
cracking. For the normal class, no tension is allowed. The assumptions
used in the · analysis are listed in the Powerhouse Structural Design
Criteria.
0242R-5051R/CG 2-13
The east wall of the powerhouse will be drained above El. 18.00 where
concrete is cast against rock, to reduce hydrostatic pressures on the
powerhouse structure. Geotextile fabric will permit water to.drain down to
El. 18.00 where water will flow through pipes through the powerhouse to the
tailrace. The concrete slabs and walls at the powerhouse discharge chamber
are provided with weep holes, to reduce hydrostatic pressures on the
completed structure during operation or dewatering of the powerhouse.
Post-tensioned rock anchors will aiso be provided between the concrete
structure and the rock foundation to enhance the stability of the
powerhouse structure.
2.4.2 Middle Fork and Nuka Diversions
Improvements at the Middle Fork and Nuka Diversions are not analyzed for
stability. However, inspection of the Nuka gabions was performed to
compare their design with other Project gabion structures for which
stability was analyzed. Also, the side slopes for the Nuka Dikes were
chosen based upon the naturally occurring slopes of the same material in
the Nuka Diversion vicinity.
0242R-5051R/CG 2-14
SECTION 3.0
SUITABILITY ASSESSMENT
3.0 SUITABILITY ASSESSMENT
This section addresses the geologic and soil conditions with respect to
their suitability to accormnodate the Bradley Lake Hydroelectric Project.
This section surmnarizes the results of the geotechnical investigations that
were made for the various project areas.
A compilation and surmnary of the various studies and field investigations
which have been conducted for the Bradley Lake Hydroelectric Project is
presented in the Geotechnical Interpretive Report (GIR) which is included
as part of the Gene:t:"al Civil Construction documents in Volume 6. The GIR
provides interpretations of the probable influence of geologic and seismic
conditions upon design, construction, and operational requirements. For
details of the conditions anticipated at specific project facilities, the
GIR and its source doctiments should be consulted.
A detailed discussion of the determination of general seismic effects and
design criteria is included in Section 7.
3 • 1 POWERHOUSE
The Powerhouse site lies atop a 20-25 ft high rock bluff adjacent to the
intertidal mud flats and salt marsh along the eastern shoreline at the head
of Kachemak Bay. The Powerhouse will contain two Pelton turoine generating
units and is to be founded in an excavated rock bench at El 40. Three
steel penstock sections will connect through a manifold to the steel tunnel
liner. It should be noted that the power conduit, manifold, and penstock
sections are sized, and are to be constructed, for 3-unit operation.
However, the Powerhouse will initially contain two operating units, with
provision for adding a third. The additional foundation excavation for the
future third unit will be excavated during the General Civil Construction
Contract and then backfilled with free-draining fill.
0242R-5052R/CG 3-1
/ ___ ..,.
A substation will be located to the north of the Powerhouse on a cut and
fill bench at El 18.
The tailrace wi 11 be a flared, excavated channel 90-175 ft wide extending
210 ft westward into the tidal flats, with an additional 175 ft wide
excavated channel at El 3.5 extending to intercept an existing slough at a
distance of approximately 900 ft. The flared section of the channel will
be lined with geotextile fabric and will be protected with riprap.
The entire. planned Powerhouse work area above the tidal flats has been
excavated to bedrock benches during the Site Preparation Contract. Prior to
excavation, vegetative cover consisted of Sitka and White spruce trees and
a sparse undergrowth of willow and alder with an organic mat of moss and
lichen.
Powerhouse excavations are expected to require dewatering throughout
construction, with shallow dewatering wells or sumps likely to be necessary
to drawdown groundwater below concrete placement elevation. Inflow for the
entire powerhouse is expected to run from 150 to 500 gpm at low tide, and
up to 500 gpm plus cofferdam leakage at highest tide.
A temporary cellular sheet-pile cofferdam will be placed below the
Powerhouse site on the tidal flats. The sheet pile sections will be driven
through the intertidal sediments to bedrock and form a cut-off extending
from the face of the bluff at the extreme northern and southern margins of
Powerhouse excavation. The cofferdam should effectively reduce groundwater
recharge through the sediments and into the excavation area from tidal
influences. Seismic data and borehole observations indicate the top of
bedrock surface below the tidal flats may be rough and irregular. Artesian
pressures of up to 6.5 psi have been recorded (with an artesian head to El
15+) within sediments immediately overlying bedrock. Once the saturated
sediments within the enclosed cofferdam area are dewatered, the groundwater
0242R-5052R/CG 3-2
pressure differential across the cofferdam may result in some leakage under
the base of the cofferdam and pumping of the cofferdam enclosed area will
be necessary.
Tailrace channel construction may be performed by hydraulic dredging or
using conventional equipment. If conventional excavation is chosen it will
begin with excavation at the bedrock/overburden contact to provide maximum
relief of artesian pressures.
Some minor bedrock excavation is necessary to achieve desired grade
immediately adjacent to the west wall of the powerhouse. Rock excavation
may proceed effectively by means of drilling and blasting. The existing top
of bedrock beneath the intertidal sediments is expected to be rough and
irregular; deadfall trees and slopewash material including large talus
blocks may be buried in the sediments.
3.2 MIDDLE FORK DIVERSION
The Middle Fork Diversion area is situated above timberline and contains
drift and colluvium-filled valleys and small bedrock knobs which outcrop as
frost-shattered rubble.
Rock outcrops in the area are mostly argillite, and locally contain up to
80% chert nodules. Many outcrops and rubble piles also contain mixed
graywacke and argillite.
Two boreholes, RM 1 and RM 2, were drilled to depths of 30 feet and 17
feet, respectively, in the diversion intake area. The overburden consisted
of cobbles and boulders in a sandy gravel matrix with occasional silt
lenses which was underlain by argillite with minor graywacke followed by
chert with argillite and minor graywacke.
0242R-5052R/CG 3-3
Test pits were dug to maximum depths of 3 feet adjacent to and along the
channel alignment and did not encounter bedrock. Overburden consisted of
variable combinations of sand, gravel and silt with occasional cobbles.
Silt and peat were predominant within the intermittent boggy areas situated
within the valley bottoms.
The diversion intake and first 500 feet of channel will be excavated
through 0 to 25 feet of overburden and into bedrock. The remainder of the
channel, including a stilling basin, will be excavated mostly in overburden
to a depth of up to 20 feet and will generally follow topographic lows
between bedrock knobs until it emerges into the Marmot Creek drainage
basin. Overburden slopes will generally be cut at 2 horizontal to 1
vertical and will be cut back to 3 horizontal to 1 vertical as necessary in
zones of finer and saturated materials.
3.3 NUKA DIVERSION
The Nuka diversion area is situated at the toe of the Nuka Glacier at about
elevation 1300. It contains a preglacial lake (Nuka Pool) behind drift
deposits and discharges through glacial outwash material to the Nuka River
and also to the Upper Bradley River over a low rock ridge forming a natural
weir.
The control structure at the Nuka River discharge will consist of a gabion
structure with discharge pipes and earth dikes both of which will be
constructed of and founded on the glacial outwash material which consists
of well graded sands and gravels with cobbles up to 8 inches. Seismic
surveys of this outlet indicate that bedrock may be 30 to 40 feet below
existing ground surface.
0242R-5052R/CG 3-4
The discharge outlet at the Upper Bradley River will consist of enlarging
the natural rock weir by controlled blasting techniques. The rock ridge is
composed of slate of the Valdez Group and contains meta-graywacke, phyllite
and slate with a strong north-northeast foliation, and near vertical dip.
A prominent and tight joint pattern cuts the foliation at approximately
right angles.
3. 4 OTHER AREAS
For specific assessments of other areas; including the darn site, upstream
cofferdam, reservoir rim, spillway, diversion tunnel, gate shaft, power
tunnel, access adit, and penstock and manifold area; the reader is referred
to Section 3 of Volume 1 of the Final Supporting Design Report for the
General Civil Construction Contract.
0242R-5052R/CG 3-5
SECTION 4.0
GEOTECHNICAL
INVESTIGATIONS
4.0 GEOTECHNICAL INVESTIGATIONS
A number of studies and investigations have been performed in the last
three decades to evaluate the technical and economic feasibility of
hydroelectric development on the Bradley River drainage system. Most of
these investigations dealt with geologic and geotechnical conditions of the
area, amassing a comprehensive body of data over the years. The earliest
studies were undertaken by the U.S. Geological Survey (USGS) and the U.S.
Army Corps of Engineers (COE). In the General Design Memorandum phase the
COE was assisted in their investigative efforts by several subcontractors.
Subsequently, overall responsibility for the Bradley Lake project was
assumed by the State of Alaska through the. Alaska Power Authority (APA).
Stone & Webster. Engineering Corporation (SWEC) was selected as the primary
engineering feasibility and design consultant for the project. Additional
licensing studies were carried out and a Federal Energy Regulatory
Commission (FERC) License was granted in 1985. Since that time, detailed
design investigations were performed throughout the project area as
engineering and design considerations were finalized.
For detailed information concerning the geotechnical investigations, refer
to Section 4.0 of Volume 1 of the Final Supporting Design Report for the
General Civil Construction Contract.
0242R-5053R/CG 4-1
SECTION 5.0
BORROW AREAS
AND QUARRY SITES
5.0 BORROW AREAS AND QUARRY SITES
Only minor compaction and backfilling operations will be performed by the
Powerhouse Contractor. Backfill and bedding material not immediately
available at the Powerhouse location will be provided by the General Civil
Construction Contractor. The reader is referred to Section 5.0 of Volume 1
of the Final Supporting Design Report for the General Civil Construction
Contract for a discussion of the borrow areas and quarry sites.
0242R-5054R/CG 5-l
SECTION 6.0
DESIGN AND
STABILITY ANALYSIS
6.0 DESIGN AND STABILITY ANALYSIS
6.1 GENERAL
The design and stability analysis has been completed on project features
which are part of the Powerhouse Construction Contract and the Middle Fork
and Nuka Diversions and Reservoir Clearing Contract.
These project features are:
• Powerhouse
• Tailrace
• Substation
• Middle Fork Diversion
• Nuka Diversion
6.2 POWERHOUSE, TAILRACE, AND SUBSTATION
The design and analysis of the Powerhouse, Tailrace, and Substation were
based on the design criteria for the Bradley Lake Hydroelectric Project
included herein and listed below:
Structural Design Criteria,
Part A
Structural Design Criteria
Part B, Section 6
Part B, Section 7
Part B, Section 8
Hydraulic Design Criteria
0242R-5055R/CG 6-1
General Structural
Design Criteria
Powerhouse
-Tailrace
Substation
-Hydraulic Turbines,
Governors and
Spherical Valves
Control System Design Criteria
Mechanical Design Criteria
Architectural Design Criteria
Electrical Design Criteria
The above criteria provide a basis for the design calculations, drawings
and stability analysis for the Powerhouse area structures. Items relative
to fire protection are also provided (see the Mechanical and Architectural
Design Criteria).
The following calculations relating the the Powerhouse, Tailrace, and
Substation are included in Volume 2:
Structural
Title
Wind Loads for Design Criteria
Snow and Ice Loads for Design
Criteria
Seismic Design Data
Powerhouse Seismic Analysis Method
Spherical Valve Foundation
Powerhouse Stability -Substructure
Powerhouse Building -West Wall
(Line E)
Generator Support Barrel
Powerhouse -Spiral Casing
0242R-SOSSR/CG 6-2
Calculation
No.
SDC.l
SDC.2
SDC.3
SDC.6
SC-214-6B
SC-212-10A
SC-222-12A
SC-219-36
SC-215-37
Structural (Continued)
Calculation
Title No.
Computer Analysis of Powerhouse Super-SS-223-7B
structure for Dead, Live, Snow, and
Seismic Loads
Member Design of Powerhouse Super-SS-223-7C
structure
Overall Analysis and Design of Main SS-223-70
Steel Framing for Powerhouse
Superstructure
Geotechnical
Title
Powerhouse Area Groundwater & Uplift
Pressures
Hydraulic
Calculation
No.
G(Ak)-27
Calculation
Title No.
Tsunami Wave Forces on the Powerhouse H-045
Probability that Combined Tide and H-052
Tsunami Water Level Exceeds Various
Levels
Notes on Powerhouse Superstructure Static and Dynamic Analysis
Calculation SS-223-70, included in Volume 2, contains the final static and
dynamic analysis for the Powerhouse superstructure. This calculation
supersedes Calculations SS-223-7B and SS-223-7C. The superseded
calculations are also included, however, as they provide important
information on the STRUDL model development and depiction (7B) and on the
load development (7C).
0242R-5055R/CG 6-3
6.3 MIDDLE FORK AND NUKA DIVERSIONS
The design of the Middle Fork and Nuka Diversions was based on the design
criteria for the Bradley Lake Hydroelectric Project included herein and
listed below:
Hydraulic Design Criteria -Middle Fork Diversion
-Nuka Diversion
Geotechnical Design Criteria -Middle Fork and Nuka
Diversions
The following calculations relating to the Middle Fork and Nuka Diversions
are included in Volume 2:
Geotechnical
Title
Middle Fork of Bradley River
Diversion Channel Alignment
Hydraulic
Calculation
No.
G(D)-103
Calculation
Title No.
Middle Fork Diversion Flood Frequency H-030
Middle Fork Bradley River Simulated H-031
Hydrograph (PMF)
Nuka Diversion Conceptual Head H-055
Delivery Curves
Middle Fork Hydraulics H-058
Notes on Nuka Diversion Gabions and Dikes
Due to the small size and non-critical nature of the gabions and dikes
at the Nuka Diversion, structural/geotechnical design and analysis
calculations were not prepared. The gabion arrangement was, however,
compared with that of gabions analyzed elewhere on the Project and the
side slopes of the dikes were chosen based upon the naturally occurring
slopes of the same material in the Nuka Diversion vicinity.
0242R-5055R/CG 6-4
SECTION 7.0
BASIS FOR
SEISMIC LOADING
7.0 BASIS FOR SEISMIC LOADING
7.1 GENERAL
A number of investigations of the seismicity of the Bradley Lake project
have been completed by the Army Corps of Engineers (COE), the US Geological
Survey (USGS), Woodward-Clyde Consultants (WCC) and Stone and Webster
Engineering Corporation (SWEC).
The USGS is conducting a continuing seismic monitoring program in the
vicinity of the site. Their most recent summary report is presented in the
Supplement to the Final Site Conditions Report.
7.2 SEISMOTECTONIC SETTING
For this information, the reader is referred to Section 7 of the Final
Supporting Design Report for the General Civil Construction Contract.
7.3 SEISMIC-DESIGN
7.3.1 Design Condition
The design earthquake studies
examined possible earthquake
estimates for each source zone.
(Woodward Clyde Consultants, 1980, 1981)
sources and associated maximum magnitude
Probability curves and tabulations of the
relative contribution from various size earthquakes were developed. An
analysis of ground motion parameters was performed and response spectra
curves were formulated for a maximum credible earthquake (MCE), producing a
0. 75g peak horizontal bedrock acceleration. A response spectra curve was
also formulated for a design basis earthquake (DBE) producing a peak
horizontal bedrock acceleration of 0.35g.
0242R-5057R/CG 7-1
The study concentrates on regional faulting, (the Aleutian Megathrust/
Benioff Zone), and four local faults (the Eagle River, Border Ranges,
Bradley River, and Bull Moose Faults) as the controlling sources to be
considered. Analysis indicated that a magnitude 8.5 event occurring on the
megathrust beneath the site and a magnitude 7.5 event occurring on the
Bor~er Ranges or Eagle River Faults, dominate the total response spectra
for the project design maximum earthquake. Seismic design parameters were
developed from the horizontal response spectra at the project area. Both
maximum expected magnitude and recurrence intervals were considered.
Details of the seismic design spectra and design accelerogram were provided
in Volume 3 of the Final Supporting Design Report for the General Ci vi 1
Construction Contract.
The summary of the alternative design cases from which. the maximum credible
and design basis events were selected are detailed below:
Peak Horizontal Peak Peak Significant
Design
Earthquake
Acceleration Velocity .Displacement Duration
(g) (in/sec) (ft) (sec)
Magnitude 7.5
(Local
Fault)
Magnitude 8.5
(Regional
Fault)
Magnitude 8.5
(Regional
Fault
Attenuated
by Distance)
0.75
0.55
0.35
7.3.2 Design Criteria
27.6 1.6 25 (MCE)
21.6 1.3 45
10.1 0.61 45 (DBE) ·
Earthquakes will affect the· operation of the Bradley Lake Project. Since
the project site is located in a seismically active area, it is desirable
for the plant to remain operational during and after minor earthquakes. A
0242R-5057R/CG 7-2
horizontal ground acceleration of O.lg has been selected for this
operational basis earthquake.
Minor damage can be expected during a moderate earthquake corresponding to
a horizontal ground acceleration of O.lg to 0.3Sg. This would involve
possible repair to such items as relays, light bulbs and non-critical
equipment. Architectural siding and windows may need repair. Most repairs
could be performed by plant personnel using spare parts or replacement
equipment.
During a major or extreme ear~hquake having a horizontal ground
acceleration of 0.3Sg to 0.7Sg, increased damage may be expected to occur.
An inspection of the plant structures and equipment will be required.
Since damage may have occurred to the generating equipment, major repairs
may be required.
With a ground acceleration greater than 0.7Sg, which is greater than the
mean maximum credible event presently predicted, increased damage would
occur, varying with the earthquake magnitude and period. Table 7-1 is a
seismic evaluation which addresses the project structures and equipment.
This evaluation provides an approximate annual probability of exceedance,
which is based on the SO year project life, and the anticipated plant
downtime for inspection and repair.
It is not economically prudent to design all structures and equipment for
the Maximum Credible Earthquake event. The critical structures and
equipment including the main darn, spillway, low level outlet gates and
operators, power tunnel, power tunnel intake and intake gate shaft, intake
gates and operators, and spherical valves and operators are designed for
the Maximum Credible Earthquake. Some repair may be required after the
event. However, the operating integrity of these structures and equipment
will be maintained during and after the Maximum Credible Earthquake.
0242R-5057R/CG 7-3
The generating equipment will be designed to remain operational during
minor earthquake events up to a horizontal ground acceleration of 0.1 g.
Minor damage can be expected from an earthquake with a horizontal ground
acceleration of O.lg to 0.3Sg. Major damage may be possible to the
generating equipment from an earthquake with a horizontal ground
acceleration of 0.35g to 0.7Sg.
The powerhouse and substation will be founded on or in rock. The
powerhouse has been designed pseudostatically to maintain its structural
integrity for a 0. 75g horizontal acceleration and for an independently
applied vertical acceleration of O.SOg. Ductility considerations have been
provided for in design to enable the structure to withstand higher
amplifications in acceleration. Additionally, the steel superstructure has
been dynamically analyzed for a horizontal ground acceleration of 0.3Sg in
accordance with the Project response spectra (Attachment A of the General
Structural Design Criteria).
Seismic loads were not considered in the design of the Middle Fork and Nuka
Diversion.
0242R-5057R/CG 7-4
Table 7-1
SEISMIC CRITERIA
Peak Horizontal
Ground Acceleration
Approximate Mean
Annual Probabi I ity
of Exceeding Specified
Acceleration (based
on 50 year project
I i fe)
Anticipated Downtime
Operational Basis (OBE)
up to.1 g
0.1 -0.2
(1-2 chances in 10
of exceeding 0.1g)
Project resumes operation
w i thin hours
Design Basis (DBE)
0.1 g to . 35 g
.007
(7 chances in 1000
of exceeding 0.35g)
Inspection and checkout
30 days. Repairs 1 to 6
months
ALLOWABLE DAMAGE LEVEL
Project Features
Dam Operational
Sp iII way
Power Tunnel
Powerhouse and No significant damage
Substation
Structures
Turbine/Generator/ Operational
Governor
0242R-5056R/CG
Operational
Architectural damage.
No significant structural
damage.
Minor damage, possible
replacement of components
with spare parts
Page 1 of 3
Extreme Basis (MCE)
.35 g to .75 g
.0004
(4 chances in 10,000
of exceeding 0.75g)
Possibly greater than
6 months
Limited structural
damage, no structural
col lapse. Potential
for functional damage.
Structur-al damage (no
structural collapse).
Significant architec-
tural damage.
Possible major damage
Table 7-1
SEISMIC CRITERIA
Operational Basis (OBE)
Cant ro Is No damage, requires
integrity check to restart.
Minor adjustments/reset
controls/spares replace-
ments.
Spherical Valves Operational
and Operators
Power Tunnel and Operational
Diversion Tunnel
S I ide Gates and
Operators,
Powerhouse Operational
Emergency Generator
15 kV Switchgear Operational
and Bus
Main Powerhouse Operational
Transformers
Substation/ Operational
Transmission Line
Emergency Lighting Operational, minor
damage (I ight bulb
replacement)
0242R-5056R/CG
Design Basis (DBE)
Limited damage, replace-
ment of components with
spares
Operational
Operational
Operational
Operational
Operational
Potential interruption
of service
Operational, minor
damage and I ight bulb
replacement
Page 2 of 3
Extreme Basis (MCE)
Possible major damage
Operational
Operational
Operational by manual
start. Manual cable
reconnection may be
required.
Minor damage
Minor damage
Out of service, possible
major damage
May require reconnection
to emergency generator
and I ight bulb replace-
ment
Operational Basis (OBE)
Fire Protection Operational
Environmental Operational
Systems (HVAC)
Permanent Camp Operational
Faci I ities
including Permanent
Housing
Barge Dock Operational
Airstrip
Access Roads
0242R-5056R/CG
Table 7-1
SEISMIC EVALUATION
Design Basis (DBE)
Operational
Operational
Operational
So i I fa i I u res
possible. Wi I I be
repaired as needed.
Page 3 of 3
Extreme Basis (MCE)
Possible damage
Possible damage
Potential for architec-
tural and structural
damage
Major soi I failures
possible. Wi I I be
repaired as needed.
SECTION 8.0
BOARD OF CONSULTANTS
"" _,
i 8.0 BOARD OF CONSULTANTS
8.1 INDEPENDENT BOARD OF CONSULTANTS
An independent Board of Consultants was formed to review the engineering
and design of the Bradley Lake Hydroelectric Project. This independent
board has met ten times since being formed in 1983. The reports of these
meetings and responses to the meetings were included as part of Appendix B
Attachment B2 of the Final Supporting Design Report for the General Civil
Construction Contract. The board meetings, convened at either the project
site, Denver, or in Anchorage, on the following dates:
Meeting 1 May 12 and 13, 1983
Meeting 2 July 11 to 15, 1983
Meeting 3 September 25 to 27, 1984
Meeting 4 November 4 and 5, 1985
Meeting 5 January 28, 1986
Meeting 6 May 6 to 8, 1986
Meeting 7 August 12 to 14, 1986
Meeting 8 December 8 to 10, 1986
Meeting 9 May 5 to 7, 1987
Meeting 10 December 17 and 18~ 1987
8.2 FERC BOARD OF CONSULTANTS
In February, 1986, the Federal Energy Regu~atory Commission approved the
use of the Alaska Power Authority Board of Consultants to be the FERC Board
of Consultants.
The FERC Board has met six times at board meetings and individual meetings
at the Hydraulic Laboratory at the Colorado State University in Fort
Collins, Colorado. The reports of these meetings and responses to the
meetings were included as part of Appendix B Attachment B3 of the Final
0242R-5059R/CG 8-1
Supporting Design Report for the General Civil Construction Contract. The
board meetings convened at either the project site, Denver, or in Anchorage
on the following dates:
Meeting 1 March 6 and 7, 1986
Meeting 2 May 28 and 29, 1986
Hydraulic Lab July 9, 1986
Meeting 3 August 18 and 19, 1986
Hydraulic Lab August 29 and September 25, 1986
Meeting 4 January 27, 1987
Meeting 5 May 26 to 28, 1987
Meeting 6 December 7 and 8, 1987
0242R-5059R/CG 8-2
APPENDIX A
DRAWINGS
EXHIBIT F
"-·
·I ,.
KACHEMAJ< BAY
......
.. ············
MUD
FLAT
········ ·····
-1000'
BRADLEY LAKE
NOTE• GENERAL PLAN
1. WASTE MATERIAL WILL EiE USED 10
CONSTRUCT RC:\o\DS, AIRSTRIP, STAGING
AREA, SWITCHYARD AREA AND OTHER
PROJECT FACILITIES AS APPROPRIATE.
2. ELEVATIONS SHOWN ARE BASED ON
PROJECT DATUM. ;
MEAN SEA LEVEL DATUM= PROJECT
DATUM PLUS 4.02. FT,
~327400
g
~
MARSHALLING YARD
EL j,5'
100
60
60
~~ -~ ~-------~~ ~ -n~r..-,-·.._...-, -. -,..---..:::::=.~------------
REQD ONLY '{HEX NUT
ON LANDING BEVEL WASHERS ( 2) ~~~~:SS BEARING PLATE
BENCH ·fx e"xB"Wi1f0'
HOLE
~, -~~ ---. ---~-------------~~ £·'"• """ =" -~'---------~·~ ~--!9fl!'t~·~------
/4xcAVATED TO EL 16.0'
---·----
POWERHOUSE EXCAVATION
EL 16.001
11, RIP RAP DETAIL
1 -1
SECTION @ E327156
SCALE A
0
0 ... ....
N ...
w
0
0 ... ....
N
M
w
2-2
SECTION @ N2112650
SCALE A
(PLATE 7)
(PLATE 7)
~~---------/
3-3
SECTION@ N2112470
SCALE A
(PLATE 7)
EXST TOR
EL MINUS 9.001
------- -~£_ _r-EXST GRADE -""'=r-<--==-,r---------.... ,,~ --~''"'tiP-----
0
0 ... ....
"' M
w
---~--\Wl!;,'lt>-- - -
EL 40-0'
4-4
SECTION @l N2112225
SCALE A
(PLATE 7)
--------~-""'---......._:,:,:\~·
EXCAVATED TO EL 40'
1-:r
_Ill
{#10 ROCK
/ DOWEL CTYP)
-----~---.--r;OJ<lr-rv-111-/ # B ROC~
w :r-~~
..J
Ill
1.25'
CTYP)
ELIMINATE BOTTOM
ROW WHEN SLOPE
HEIGHT IS LESS
THAN 15'
DETAIL A
TYPICAL ROrK SUPPORT
NTS'
DOWELCTYP)
•a ROCK BOLTS
@ 50'0C EW
STAGGERED
CHAIN LINK MESH,
OVER TUNNEL PORTAL
INSTALL UNDER ALL PLATES
CPT H TO PT I, PLATE 7
M < B
::;: '
...J;--::... -=--Ni ___ --= =
GROUT:SLOW
RESIN FOR FULL I
ENCAPSULATION
THREADBAR
2
..
# B GRADE 60r-{ t -:_
_[T'fY""P) If BROCK BOLTS
0 @l 4,0' OC EW I
DETAIL B
TYPICAL ROCK SUPPORT
ABOVE EL 39,0' BENCH
NTS
STAGGERED
4' CTYP) DETAIL E
NTS
5.0' I CTYP) EL 39.0'
DETAIL F
TYPICAL ROCK SUPPORT
ABOVE EL1B.O' BENCH
SCALE B
ROAD-DETAIL D ....... -............._
# 6 GRADE 60
THREADBAR ROCK
DOWELS 10' LONG-
DEl E
DETAIL C
TYPICAL BENCH SUPPORTS
SCALE B
DETAIL D
SCALE B
(PLATE 7 )
EL VARIES (ROAD CUT)
40.0'
0 10 20FEET
I .....
SCALE B: 1':10'
0 20 40FEET
I lillll
SCALE A: 1":20'
THIS DRAWING SHOWS BOTH
SITE PREPARATION AND
CIVIL CONSTRUCTION EXCAVATION
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
CIVIL CONSTRUCTION EXCAVATION
AT POWERHOUSE
ELEVATIONS
STONE ~ WEBSTER
ENGINEERING CORPORATION PLATE B
11° ~ STL
LINER--
6'-6'¢ STL PENSTOCK
6!.6" DIA PENSTOCK
IN TRENCH
NTS
~ STL LINER
LINER
ENCASED IN
CONCRETE
11' DfA STEEL LINER
o~~~~~~0--~2~0FEET I~ iAOII
EL 25.05'
DRAINS
_ff!:§TOCK CONC ENCASED
\ROAD SURFACE
\
PENSTOCK, MANIFOLD & POWERHOUSE
C?(FUTURE)
!
HIGH PRESS~RE
ELLIPSOIDAL/ HEAD
EL.41 1
EL 15.0' ' ' '--,~'""\
FUTURE UNIT EXCAVATION
0~~~~1~0 ....... 20FEET
EL 18'
T.O. RAIL
EL 65'
TIDAL FLATS
EL VARIES
(EL 6'!)
~ ~ ...
i2 -------,,
E
24'-QII
E-L 421
. .-:•::-~ .....
GATE
EL 21'
RUNN~R
EL ~5 HIGHE§T TIDE
C_EL 11.4 ~
EL MINUS 9'±
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
90 MW PEL TON POWERHOUSE
STONE & WEBSTER
ENGINEERING CORPORATION PLATE 9
2220
2200
2180
2160
2140
)
INTAKE BASIN
MIDDLE FORK
BRADLEY RIVER
CHANNEL
2170r-----------------~----------------------~2·~~~SL~O~PE~~~--------------==================~====~~==~~~---
2120~---4----~----~----~~--~----------------------~----------------r-----•~--~----~----~~~-+-----+----~
5•00
STATION
6•00 7•00 8•00 9<00 0.00 2•00 3+00 4•00
<t PROFILE
~ 2'
TYPICAL
CHANNEL EXCAVATION
IN ROCK & OVERBURDEN
(NTS)
LOOKING UPSTREAM
;:
0..
<i_ SLOPE VARIES
I
"'><'j~--~;--~--1?:;--~u---
2'LJ~
~ MIN
TYPICAL
CHANNEL EXCAVATION
IN OVERBURDEN
(NTS)
LOOKING UPSTREAM
:;::
)>
-; n
J:
r
z
1'1
~
)>
'I'
0
2-2
WASTE FILL
AREA 1
(NTS)
0
CHANNEL
'<.
40 80FEET ~~
SCALE A:1" ,40'-CY'
AREA PLAN
(NTS)
SLOPE OF EXCAVATION
STA 0•00 TO STA 1+70
AS PER TYPICAL SECTION
FOR EXCAVATION IN
ROCK & OVERBURDEN
<i_ BASIN
I
I
1-1
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
MIDDLE FORK DIVERSION
INTAKE BASIN & UPPER CHANNEL
PLAN, PROFILE & SECTIONS
PLATE 11
i
li
"' z
0
0
'T\
14'1• SLP ~ 21BOL-~I\ "'~·· M,. " ' z 2160 : l \ I I 2•1. SLP-r
Q ~l~~==EL=2134=o·==~~--~--~~--~--~~l~ )>
1 "'' . = ,;oo
' "" " ·~· ,.... l w !;< ' 11•00 12•00 2100 . i-10•00 · STATION w z
-'
I u ,_
"" ::>:
q;_ PROFI_LE
~F"ILLASRE~
TO EXTENT------,
PRACTICAL lil.2 -
I ·~· ••.•. EL 2170.d MAX ~ 2150.0'MJN "'.::---:::::----..::--.::::: .....
UNOIFFERENTitJED ... ~...... . '::::--...
WASTE FILL~ -...::::: ......
EXST
GRD
3-3
WASTE FILL
AREA 2
I 50.dMAXI 'K5.01 MIN
IF USED
lil.3
I
4-4
WASTE FILL
AREA 3
MIN 6' SHOT ROCK
BRADLEY LAKE PHOYWDRE~E~~~~~~.;~OJECT ALASKA
MIDDLE FORK DIVERSION
STILLING BASIN & LOWER CHANNEL
PLAN, PROFILE & SECTIONS .
---------------------~
KACHEMAK BAY
CONSTRUCTION
UNDER SITE
PREPARATION
CONTRACT
40·
60
~2111600
"' ~
70·------
TAILRACE::-\
(CIVIL
CONSTRUCTION
CONTRACT)
MARSHALLING YARD
SHOP/WAREHOUSE
CONSTRUCTION UNDER
SITE PREPARATION CONTRACT
--.::::.-
' 0 50 100 FEET I _......,.
SCALE· 1,: 50'
--!-;; 2111600
"' N
"" N g
-----:::_-
~--------. ----,
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
GENERAL ARRANGEMENT
PERMANENT CAMP
& POWERHOUSE
PLATE 14
I
EL20'
POWERHOUSE
~
~
t;;
~327000
PLOT PLAN-POWERHOUSE SUBSTATION
0 1 lO' .0' ,....._.. .
ICAUINfiiT
0
~
~ t;;
-----«Jaaa ~
~
~
----G!oaa 0
DEAD EN
TOWERS
D
NO DEAD E
TOWERS
"-
~ ----~aaa
---4xlaoa "-
--~aoa "
f327000
~ _,....,..,.,
~ ~
r r~
...-:">. ~
\LINE
DISCONNECT SWITCH
ON DEAD END TOWERS
CROSSING
,.oo~"'t ~ r.r-..
~ ~ WOODEN H-TOWER
SWITCH
~ (~ ~f ? J/ \:~
/LINE CROSSING
DISCONNECT SWITCH
~~ERS
' 'V 'V
~_[ ~
-'9 ~
PLAN
0~~~~~16;. ...... ~32FEET
SCALE:~: 11-011
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWERHOUSE SUBSTATION AND
BRADLEY JUNCTION
PLATE 16
TYPICAL TRANSMISSION STRUCTURE
SCALE IN FEET
----------------------
OYUB-
MGSIL ®_
•lt---Y
115KV LINES
TO BRADLEY JUNCTION
OYUB-t:LINE2\SA
MGS2~
ovue.-
MDS2L
OYUB~ .tOYUB-OYUB-®OYUB-
MGSIB E MDS21 PCB2 yMDS22 115KV BUS OYUS-28 , --1---3~E~11~5~K~v~e.u~s~o~v~u~e~-~~e.~--------, ___ _.1 --~c=J~;--~T~--' --------~~~~~~~~--~~
E OYUB-)® OYUB-J® OYUB-OYUB-
VT2B
OYUB~ MGS11
'
OYUB~MGS\2
•I
E VT1B " -MGS21 J, -MGS22
MGS3B ® _ E MDS31 ~~~~-@ MDS32
OYUB[J-· MGS41 ,,
OYuB-~OYUB-OYUB-
~ .115KV BUS OYUB-38 _ c=J )' 115KV BUS OYUB-4B 1YU~~ ~i:---i-~1Y-"'U""'B"'--=-"'-'-'......._......._____ i_4)0vUBI---..... i,_)-{E)_.OYU-B-----'"-"-"O.:.....::"'"-'"'-"':......;.:;:..._ _ _,__
MGS~~ MDSIT 1 -MGS31 1 -MGS 32
,, .1MTX-XM1
MN XFMR1 ,
1GMB-XV1
33,6/45.1 /56.3MVA,13.8 -115KV
3PH,6DHZ,Z=9"/o
DEGS-G1
. . 9. 1NPS-ACB1D
120011
. ~DIESEL GEN GEN IJ'o. KVA, 480V.
. 3PH,6DHZ
. ONJS-XS1 l100011333KVA
9.
STA. SERVT 12800-48DV
XFMR1 3PH,6DHZ ~EGS ACB3D1 1GMS-ACB1 -
GEN BRKRNQ 1
3DDDA ) DNJS-ACB1D1 ) DNJS-ACB1D3
[ DNJS-:JS1 1 l
4BOV BUS ·
DNJS-
''~-· -ACB1D2
1GMB-XV2
""·-~· ([~
NEUTXFMRlb
,::t, 2'lf'S -ACB2D 1:: 12COA
ONJS-XS2 , y 1D00/1~33KVA
STA. SERV ulu13800·480V
XFMR2 T 3PH,6DHZ
) ON.JS-ACB201
ONJS-US2
4BOV BUS
6
~8>-
2GMB-XV1
~ 2GMS-ACB1
GEN BRKR NO. 2
3DDDA
-·r:=r
VT·.
6 ~8>-vT
2GMB-XV2
2GMS-G1
GEN N0.2
13.8 KV,3PH,60HZ
59MVA,095PF
·------------------------------------------,
TO DIAMOND RIDGE ~---r---ro ="' . I. --· . '-,,r ,,r
LINE 1 LINE 2
TO BRADLEY LAKE
BRADLEY JUNCTION
;r,2NPS-ACB4D ~ 1NPS-ACB30
-~ 1200A ];! . 1200A
1 _1 '-----------------~-4-ONPS-XA1
-~pROJECT FACILITIES SERVICE XFMR NO.1
"= Z.Ti K'IA.13.a-12.47KV
JPH,6DHZ
FEEDER TO
PERMANENT
PROJECT FACILITIES
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
MAIN ONE LINE DIAGRAM
STONE I WEBSTER
ENGINEERING CORPORATION PLATE 17
I
i
I
I
I
I
N 2077198
E 369675
"' " "' CJ>
:!i
w
I
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\
I
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' ', , __
---
I '
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{
1
/ 1 I I
I I 1 ••• -"/
f : ,.:'/ / / / / .'·' l,
1
: I / / ,J ~ /
I I / 'I / / I : I I I /I' \ft/1:'/ / ~ilf///,/
+
I: I I I I I :
' IQ 1on1 : ~· 10{)
IM
IW
I
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/
PLAN-OUTLET STRUCTURE
SCALE A
~~ o I ~ I .... ,.,
~2077400
0 20 40 FEET
~:--WI
SCALE A: 1",.20'
AREA PLAN
N.T.S.
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
NUKA DIVERSION
NUKA RIVER OUTLET SfRUClURE
PLAN
,------------------------------------------------------------------------------·-----------------------------------------------------------------------.
EL 1290±
lxsT
GRD 1 . t CHANNEL ____ ....:...F=LO::.W.:..:__~
,L
SLOPE 5H:1V 0
---ai ---1---1--
4H:1V SLOPE
(TYP)
L.
2
-"-
't DIKE
I
>1w "0 ~v:·
I
I
[/-MEMBRANE LINER
I
I
I
ENLARGED PLAN-OUTLET STRUCTURE
SCALE A
3-3
SCALE A
G) EL 1282.0'
@ EL 1285,0'
@ EL 1288.0'
GABION CONSTRUCTION SEQUENCE
SCALE B
0~~~~10:. .. ;;:20 FEET
SCALE a: 1'•10'
0~~~~5~~;;;10FEET
SCALE A' 1'• 5
@ EL 1291.0'
~
------~-r
@ EL 1294.0'
EL 1296.0'
EXST GRADE
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
NUKA DIVERSION
DETAILS
STONE & V.OEBSTER
ENGINEERING CORPORATION PLATE 22
0 g
$
"' N2078400 ~
PLAN
SCALE A
I
(
I
I
/
I
/
/ I / /
/
/
I
I
4-4
SCALE A
zo FEET
I
TAILRACE
TAILRACE
SPIRAL CASING PLAN EL 15.00'
0 B 16 FEET
I 1111
SCALE A; -b,'•I'•O'
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
PLATE 24
3 MTX-XMI
(SPARE)
TURBINE FLOOR PLAN EL 21.00'
TOC EL 2~00' (UNLESS OTHERWISE NOTED)
LEGEND:
MCC MOTOR CONTROL CENTER
FHC FIRE HOSE CABINET
ON DOWN
MH
SFH
MANHOLE
SPHERICAL VALVE
0 6 16 FEET
I ---scALE A: J.'•1'-0'
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWERHOUSE
GENERAL ARRANGEMENT
PLAN EL 21.00'
STONE l "'fOSTER
ENGINEERING CORPORATION PLATE 25
SF6 SUBSTATION
ROOM
CRANE S TOP-
AIR INTAK
CANOPY
E
c·
DUCTS />BCNE r(SF6 BUS
u -
l --
:~ lAJ
FA~O.I
AHUJ
FN41 -
1~1 --
Jt-1"-9" 20'-o•
CD
--HANDRAIL
FHC
'
STORAGE RM STORAGE RM
NO, 1 NO.2
' I
--
i I
I 20'·0' 20'·01
0 0
L_ ______________________________________________ __
EL 42.00 1 I GENERATOR FLOOR PLAN Ill> 6J --16010N .. BRIDGE CRANE
!PARKED FDSITIONl
--IU.-" CRAN~ RAIL --~CRANE STOP
...v (o1)· - ---PANEL ---D ·rrowER TYP) FHC
'
.QMCC5 0 ' k'_ D~ Ww ~%3· 6FN2
.
~f~l ~ \ PT\fp1 !. 0FN 6 HEATING II. VENTILATION
"o TELECOMM · if EQUIPMENT ROOM F= ~b~!fGE (M F~O. i I ,---t§ I= -~ EQUIP RM "' ~ I I t= AHU1 AHU5 I= AHU7 ' ' I ~~-------r I--1~··1 1-i 0 15~::.1'.31 1§~1. -a,
' '
I 20'-o' I 2d-o• 20'-o~ I 20'·0' I 20'-o• 11-91
.8 0 ,0~ MEZZANINE FLOOR PLAN EL 60 0 0 0 ®
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWERHOUSE
GENERAL ARRANGEMENT
PLANS EL 42.00' &. EL 60~o··
PLATE 26
16o'-o'
2o'-o' 20'-o' 2o'-o' 2o'-o oo'-o"
10'-o• 1o'cQ' 10~0' 10'-o'
~ UNIT 1 U"liT 2
TRANSMISSON
LINE BY OT>ERS .
2o'-o' 2o'-o'
I
GENERATOR FLOOR
EL 42.00'
0 B 16 FEET I ,_
SCALE A: ~·1'-0'
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
POWERHOUSE
GENERAL ARRANGEMENT
LONGITUDINAL SECTION
APPENDIX B
AITACHMENTS
CONSTRUCTION SCHEDULE
CONTRACT DATES
l ':Ull 1 <,ll'll'l I '::ltl':J 1 ':J<,!Ii! I '::l':J SCHEDULE 1 N I r LH_ lli M A _!!_ _l'l_ I F M A M 5 I N I F l'tlli M A _!!_ _l'l_ I F I M lli 11 5 IN
CATERING CONTR -PREAWARD II!~~"----------_: ___ --I I I I I I I ILHit.tU~b l.UI'III'I PREQWARD I I I I I
1-C-A-TE_R_I_N_G_CO_N_T_R_A_C_T ________ _, I I ~~fERfNG-CONTRAff-.-------:-------~-------~--------.-------:-------~-------~--------.-------:-------~-------~--
~-------------------------------------.1.0~3~0~ • 1 I I I I I CIVIL CONTR -PREAWARD ---------------------RD I I I I I I 1-M-0-BI~L-IZ-AT-IO_N _______ _,ICIVIL ~oNJt< ,t'Kt.HwH~--A~¥--+;r I I I I I I I I I I I
I ROBILILATION I . I
GENERAL s nE woRK I I I @~~E:FiA"csnE:~VoRir-:-------~-------~-------:-------~---~---~-------~-------------------------+1. I
PERM. FACILITIES I I I ~:·FACILITIES I I I I I I I I I I
MARSH. YARD ROAD : I : ~it YARD ~DAD I I I I I I I : : :
SPILLWAY I I I §~~LLWAY . -----~-------il-: I :
I
coFFDAM &: PH EXC I I I ~fF'oAtr&.-"P!i"Exc I
I
PH BACKFILL/YARD
I
hKFILLIYARD I
: : I ~lLR~tt
I
I •------.~--· TAILRACE
COFFOAM & DAM EXC
DAM FDN &: CONC.PLINTH
DAM EMBANKMENT
PORTALS,MANFLD &: PENSTOCKS EXC
I I ~i~t:D1fE~L OET:TifE'R TBHI I I I
: ~~~TALS~D & PENSTOCKS EXC I I
I
I ~NCR-Ef~-FACE I
DAM CONCRETE FACE
PROCURE &: DELIVER TBM
I I : ~f{}sfaEKs IN~r/coNcRETE I
I §i~-t-wR-fONNEL ·3+46 -·31+60 I I
PENSTOCKS INST/CONCRETE
D&S LWR TUNNEL 3+46 -31+6~
TBH ASSEMBLY I I : ~ ASSEMBLY: I I
I I I +1~-EXt.--§1+60--=..:177+!0 I
1 I I " I I
TBM EXC. 31+6~ -177+5~
STEEL LINER/TUNNEL TESTING
I I I I ~ rflc-torJcRErt-rmEif-I I I I
: I : I ~i~ErJfNER/TUNNEL 1Es'FiNG I
LWR TNL CONCRETE LINER
MANFLD INST/CONCRETE/TEST
t:::::::::::::::~::::::::::::::::::~_j----~1------------------------~1 ----------------------~---------------------------------------sMrl. I~ ~
SCHEDULE
VERTICAL TNL EXC
VERTICAL TNL LINING
INTAKE CHANNEL EXC
INTAKE PORTAL EXC
UPR TUNNEL EXC
PWR TNL GATE SHAFT EXC
UPR TNL/INTAKE CONCRETE
INTAKE GATES/TRASHRACK/TEST
COMPL SHAFT/GATES/TEST
BREACH PLUG/UNDERWATER EXC
DIV.TUNNEL SHAFT EXC
DIV. TUNNEL COMPLETE
1~1::!
IN IFlMIAIM
i
I~I:Hl
lli ~ IN
. I
1'::169 144
l f LM LH _11 I 1'1 <i IN 11-U'IIHIM IRIS IN LtiMIAIM IH ~ IN
~~~ICAL:TNL EX~ I
: ~ItAL TN~ LINING
---:-------+..:..--
~AKE PbRTAL E:XC I : I I I
~~u~NEL Exc I I I : I
I : ~ TNL GATE SHAFT EXC : I :
I I -~6~~-r"NCirNTAKE coNcRETE I I
I I I : .E 0 GATES/~RASHRAtK/TEST1
: I I ~g~F>r-sHfiFfiGATEs/~EsT I I
I I I : i~~AtH P~UG/UNOERWATER EXC I
I I I I
1 ~U~NEL SHAFT EX~ :
I I
I I I I SIG~-TDNNECiiiMPLETE I
I I I : : I B~~.os~ItizAnoN
I I I I *~~e:rfV6iin=rfrmG---.------= ..
DE MOBILIZATION
RESERVOIR FILLING
DIVERSIONS -PRECONSTRUCTION I M~e:"Rsf6Ns'"~-PREcoNsTRucr.IoN I I I
I I ~-~ORK DI~ERSIO~ I :
M~lf-dfV~kSION :
MIDDLE FORK DIVERSION
NUKA DIVERS ION
PROCURE TURBINES/GENERATORS 150 1 -----~----------------------.:-------~-------~------.--------;-------PROCURE TURBINES/GENERAIOK~ 1
1---------------i'ttSS ------------------------------------~----------------------!-------~-------.--------·-------~----PROCURE SCADA ~~-=P=w=H=s==c=o=NT=R=A=c=T==-==P=R=E=A=w=A=R=D============~~:~~~~;~N;~~;-~::-r----~-.~:--------+----· I I : : : : : :
I 162, . I MOBILIZATION : I I 1HOBILIZATION------,..-· I I
PROCURE SUBSTATION ~~~~ORE sUBSTATTtJtt-----7 --+---~------~·
PROCURE PWHS STEEL & CRANE l66" • • . I
PRocuRE PwHs=sf€EC_&_'"cR'ANE-----~--
. ,1.68 ° .
1 I 'SussTAJ ION ' ::::::: --.---•----r-------· SUBSTATION
E::::::=:=:=:::_~------------------j_----~1 --------------------------------------------------------~-----------------------s~· 2of •
P::ltltl ~ SCHEDULE I riM M HI':> IN LLIM Lttl1'1 H ':> IN I I'" I M I HIM Ll'! II'"IMIHIM
PWHS CONCRETE ------------·-.. ----·
PWHS SUPERSTRUCTURE : : ~~~~H;;s~so~P~E~R5~1~Ff~dt~-f~O~RE~-~--~,~~~-:3+----~------~-------~-------~--
PWHS YARD I I I I I ~YARb--
INSTALL ~ TEST UNIT I I ~~~~rf![:ct-re:sY-dNrrr----~----:.----------1-----i-:---· I I
INSTALL & TEST UNIT II
MELH/ELECTR EQPMT.
START -UP UN IT I
~~~~:rirccs;-·rts-ramrrr-----~----------~-~-----~3----· I :
I : ~:~HiEtYerirE"ort1t:----.-----+~-~-I I
I 1 1 : I I 1 ~f~Rl-:up UNtT I
. I
START -UP UN IT I I I 1 I 1 1 I 1 ~f~fff-up UNIT II
DEMOBILIZATION
1---T_R_. L_r_N_E_c_L_E_AR_r_N_G_-_P_R_E_Aw_A_R_D ___ ----ji~~ LINE cLEAR !'t .. ii:.---=--,;~E:'AwARo I · I I
:225 . I •
1
1 1 1 1
:
1 ~~~otrrrzATIQ~
I
TR. LINE cLEARING I I ~R:DN"CeCE:f!IfftJG-----t--
~----------------~------~~~sa I • TR. LINE -PREAWARD -----------------------------:------~---· I
1-----------------------------~IIK.LlN~ rncnwn~U
TR.LINE PROCUREMENT
TR.LINE MOBILIZATION
TR.LINE CONSTRUCTION
SITE REHAB -PREAWARD
SITE REHABILITATION
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BRADLEY LK SCHEDULE (7/88-38 Mo-Adjl
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Sheet 3 of 3
Data Da-t•• IBJANBS Plat Dote I 22JULB8
BRIIUY UI:E III5TER 50£IU.f -115T6
PART B
DESIGN CRITERIA
SECTION 1.0
HYDRAULIC
DESIGN CRITERIA
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .0. NO. 15800
HYDRAULIC TURBINES, GOVERNORS, AND SPHERICAL VALVES ---------~ ------------------
PERFORMANCE CRITERIA
REVISION 2
DATE: MARCH 28, 1988
00629A-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
TABLE OF CONTENTS
OBJECTIVES
REFERENCES
1.0
1.1
1.2
1.3
1.4
1.5
1.6
DESCRIPTION
General
Contract Packaging
Turbine/Generator Sizing
Hydraulic Turbines
Governors
Spherical Valves
2.0 TURBINE HEAD
2.1 Water Levels and Tunnel Discharge
2.2 Head Loss Calculation
2.3 Design Pressure
3.0 OPERATION
3.1 Operation of Units
3.2 Regulation of Turbines
3.3 Operation of Spherical Valves
3.4 Sluicing through the Turbine
3.5 Flood Operation
4.0 DESIGN CONSIDERATIONS
4.1 Hydraulic Turbines
4.1.1 Runner·
4.1.2 Shaft -Bearing System
4.1.3 Shaft Seal
4.1.4
4.1.5
4.1.6
Tailrace Depression System
Cooling Water System
Spiral Distributor
Pa:ge No.
1
1
1
1
2
2
2
3
4
7
7
8
9
10
10
11
11
12
13
13
13
13
13
14
14
15
16
00629B-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
TABLE OF CONTENTS (Cont 1 d)
Page No.
4.1. 7 Runner Chamber 17
4.1.8 Needle Valves 17
4.1.9 Deflectors 17
4.1.10 Instrumentation 18
4.2 Spherical Valves 18
4.2.1 Valve Body 18
4.2.2 Connection Pipes 18
4.2.3 By-Pass System 19
4.2.4 Oil Pressure System 19
4.2.5 Valve Seals 19
00629B-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 1
OBJECTIVES
The main objective of this criteria is to provide basic guidelines for
selection and preparation of specifications for hydraulic turbines,
governors and spherical valves. The document addresses general configu-
ration of the powerhouse, rating of the units, operation, and special
requirements on selection of the equipment.
REFERENCES
1. FERC License Application for Bradley Lake Hydroelectric Project
2. SWEC: Master Specifications for:
-Hydraulic Turbines and Pump-Turbines
Spherical Valves
-Hydraulic Turbines and Pump-Turbines Governors
3. Turbine Manufacturer Information and Design Data from:
-Allis Chalmers -Fuji -Kvaerner Brug
-Dominion Bridge -Hitachi -Vevey
-Escher Wyss -Hydroart -Voith
4. Fuji design data furnished under Contract No. 2890033 with APA
5. Hydraulic Design Criteria: Tailrace Channel, Bradley Lake
Hydroelectric Project
6. Structural Design Criteria: Powerhouse, Bradley Lake
Hydroelectric Project
1.0 DESCRIPTION
1.1 GENERAL
The powerhouse will contain two 45-MW units with prov1s1ons to install a
third unit at a later date. Six ,jet vertical Pelton tur,bines will be
directly coupled to synchronous a-c generators. Water for the powerhouse
will be supplied by an 11-foot diameter power conduit, approximately
19,000 feet long. The power conduit manifolds into three branches immedi-
ately upstream of the powerhouse. This arrangement requires a spherical
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 2
valve to be provided for each of the initial two turbines and a pressure
closure head for the future third unit. Each unit will be equipped with
an electric-hydraulic governor.
1.2 CONTRACT PACKAGING
It is considered advantageous that the hydraulic turbines, generators,
governors, and spherical valves be awarded as one contract package
preferably to a hydraulic turbine manufacturer or a consortium of a
turbine and generator manufacturer. This arrangement will reduce inter-
facing problems, contract administration efforts, and assure a better
product in general. Any two or more identical items must be made by the
same manufacturer.
1.3 TURBINE/GENERATOR SIZING
The turbines will be sized so as to provide 135 MW on the high voltage
side of the transformers, with three units operating under minimum
operating reservoir El. 1080. The generators will be rated for maximum
power output of two turbines operating simultaneously under reservoir El.
1180 and tide below El. 6.0. Combined rating of two generators will be
the' maximum output of the two unit powerhouse. TABLE 1, which summarizes
operating conditions of the units at full flow under ·key reservoir
levels, shows turbine rating as point C and generator rating as point K.
1.4 HYDRAULIC TURBINES
Although the design head is well within the range normally covered by
Francis turbines, Pelton turbines were selected for their flatter effi-
ciency curve and for preferred regulating features such as lower
overspeed and pressure rise caused by load rejection. Although the Pelton
has the ability to reject the load much faster than Francis turbines, the
rate to accept load will be limited by the possibility· of an
underpressure in the power conduit.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 3
The turbines will be rated at the net head of 920 feet when three units
operate at reservoir El. 1080 to produce 63,500 HP each or the total high r
voltage output of 135 MW. Synchronous speed will be specified at 300 rpm.
Efficiency at this point is expected in the order of 87.6 percent. Data
indicate the average reservoir level at El. 1155 which, with turbine
setting at El. 15 and the head loss of approximately 30 feet for the
average operating flow of 800 cfs, would result in the turbine design net
head of 1110 feet. Peak efficiency of the turbine (top of hill chart)
should occur at, or as close as possible to, this head.
The turbines will be furnished with a welded steel spiral distributor
(spiral case), fully embedded in concrete. The tailrace gate will facili-·
tate partial or complete dewatering of the turbine-chamber. Runners will
be removable from below through the runner access gallery •. -
Three bearings will be provided for the turbine -generator shaft system.
These are: (1) turbine guide, (2) generator guide, and (3) combination
thrust/guide bearing on the top of the generator. This arrangement allows
for walking space in the turbine pit.
1.5 GOVERNORS
A digital electronic governor will be uied. C~ntrol will be of PID type.
The governor will be equipped with automatic needle s_election, and
independent speed supervision. Speed, power, and manual limit control
modes will be provided.
Governor electronics will be located in the Main Control Board. A single
panel section for each unit will contain the_governor electronics, and
turbine control and monitoring devices. Each governor will be a separate
system and operate independently.
Deflector control will be the cut-in type. All deflectors operati"ng· in
. parallel will continuously follow the edge of the wa·ter jet stream. On
small load changes the needles will modulate to control flow. On large
load reductions the deflector cuts in to reduce the flow directed on the
00629C-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 4
runner buckets at a fast rate. The needle closure follows at much slower
rate. The result is faster response time to load rejections even with the
long needle closing times required for Bradley Lake.
Each governor will have an independent oil systemf. consisting of an
accumulator tank, sump tank, dual oil pumps, controls, connecting piping,
and servomotors.
1.6 SPHERICAL VALVES
The spherical valve was selected as the only suitable shut off valve for
the head range experienced on the Bradley Lake Project.
The spherical valve wiH be rigidly connected to the~ _penst.ock and will
have a sliding type coupling on the turbine side. A closure section· on
the downstream side will accommodate an ultrasonic system for flow
measurement. A by-pass system will be provided to equalize pressure on
both sides of the valve prior to opening.
The plug will be opened by one single action, oil operated servomotor and
closed by a counter-weight. The downstream operating seal of the valve
will be stainless steel copper alloy fixed type. The upstream
maintenance seal will be water operat·ed.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
TABLE 1
FULL LOAD DATA UNDER VARIOUS RESERVOIR ELEVATIONS
AND NUMBERS OF UNITS
Operating Point A B c D E
No. of Units 1 2. 3 1 2
Reservoir El. 1080.0 1080.0 1080.0 1155 .o 1155 .o
Runner Centerline El. 15.0 15.0 15.0 15.0 15.0
Gross Head 1065.0 1065.0 1065.0 1140.0 1140 .o
Head Loss, ft 23.7 71.1 140.6 25.3 76.0
Net Head, ft 1041.3 993.9 924.4 1114.7 1064.0
Tunnel Velocity, fps 7.61 14.88 21.52 7.88 15.39
Loss Coef (HL/Q2) 45.26 35.56 33.62 45.21:-35.52
Station Serv. Pwr., MW 1.0 1.5 2.0 1.0 1.5
Total P-H Flow, cfs 723.6 1413.9 2045.3 748.6 1462.9
Turbine Eff, PCT 89.75 89.40 88.0 89.75 89.80
Needle Valv Opng, PCT 100 100 100 100 100
Turbine Flow, cfs 723.6 706.9 681.8 748.6 731.4
Turbine Power Out, kW 57222 53152 46925 63374 59135
Generator Eff, PCT 98.00 98.00 97.80 98.00-98.00
Generator MVA (p£=0.95) 59.0 54.8 48.3 65.4 61.0
Total H-V Output, MW 54.8 102.2 135.0 60.8 113.8
Page 5
F
2
1155 .o.
15.0
1140 .o
38.6
1101.4
10.96
35.52
1.5
1041.9
90.70
70
520.9
44036
97.85
45.4
84.3
00629C-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
TABLE 1
FULL LOAD DATA UNDER VARIOUS RESERVOIR ELEVATIONS
AND NUMBERS OF UNITS
(Continued)
Operating Point G H I J K
No. of Units 1 2 3 1 2
Reservoir El. 1190.6 1190.6 1190.6 1180.0 1180.0
Runner Centerline El. 15.0 15.0 15.0 15.0 15.0
Gross Head 1175.6 1175.6 1175.6 1165.0 1165 .o
Head Loss, ft 26.1 78.3 155.3 25.9 77.6
Net Head, ft 1149.5 1097.3 1020.3 1139.1 1087.4
Tunnel Velocity, fps 8.00 15.63 22.61 7. 96-15.56
Loss Coef (HL/Q2) 45.18 35.50 33.63 45.19 35.50
Station Serv. Pwr. MW 1.0 1.5 2.0 1.0 1.5
Total P-H Flow, cfs 760.3 1485.6 2148.8 756.8 1478.8
Turbine Eff, PCT 89.50 89.80 89.65 89.60 89.80
Needle Valv Opng, PCT 100 100 100 100 100
Turbine Flow, cfs 760.3 742.8 716.3 756.8 739.4
Turbine Power Out,kW 66182 61930 55439 65362 61094
Generator Eff, PCT 98.00 98.00 98.00 98.00 98.00
Generator MVA (pf=0.95) 68.3 63.9 57.2 67.4 63.0
Total H-V Output, MW 63.5 119.3 160.2 62.7 117.7
Synchronous speed 300 rpm
Transformer efficiency 99.5 PCT
Power tunnel diameter 11 feet
Power tunnel length, approximately 19000 feet
Page 6
L
3
1180~0
15.0
1165.0
153.9
1011.1
22.51
33.63
2.0
2139.1
89.55
100
713.0
54630
98.00
56.4
157.8
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
2.0 TURBINE HEAD
2.1 WATER LEVELS AND TUNNEL DISCHARGE -TABLE 2
Tunnel Discharge -three units, full power,
three units, full power,
-two units, full power,
Reservoir Levels -Maximum Flood
-Average Operating Level
-Normal Maximum Operating
-Normal Minimum Operating
-Emergency Drawdown Level
Tailrace Levels -Highest Tide (estimated)
-Mean Higher High Water
-Mean High Water
-Mean Sea Level
-Mean Low Water
-Mean Lower Low Water
-Lowest Tide (estimated)
Storm surge wave height at the powerhouse:
(50 year recurrence interval)
Sustained wave height at the powerhouse:
El. 1180
El. 1080
El. 1080,
Level
Level
El. 11.37
El. 4.78
El. 3.97
El. -4.02
El.-12.02
El.-13. 63
El.-19.63
Maximum credible tsunami wave height (estimated)
Notes:
2140 cfs
2045 cfs
1415 cfs
El. 1190.6
El. 1155
El. 1180
El. 1080
El. 1060
Excd 1 nce
0.0 %
5.5 %
8.5 %
50.0 %
87.5 %
93.0 %
100.0 %
El. 13.3
5 feet
25 feet
1. All elevations related to Bradley Lake Project Datum.
Page 7
2. For the tailrace exceedance curve, see Hydraulic Design Crite-
ria: Tailrace Channel.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 8
2.2 HEAD LOSS CALCULATION
Friction losses in the power conduit. were calculated for each flow
individually using Darcy-Weisbach formula. Local losses f_or entrance,
trashracks, piers, bends, bifurcations, conversions and diversions were
established and added to the friction losses to determine the total head
loss.
The head loss is a. significant factor in selecting the turbine rating. To
calculate the turbine flow, equations for head loss and energy have to be
solved simultaneously. Output at the turbine shaft must be 3x47.5 MW to
assure the net output of 135 MW on.the HV terminals of the transformer.
This conditions must be met while operating under the minimum reservoir
level El. 1080. The following table summarizes the res.ults ·of head loss
calculations:
TABLE 3
SUMMARY OF HEAD LOSS CALCULATION
No. of Units
Lake Level
Power Tunnel Discharge
Total Head Loss
Head Loss Coeff.
No. of Units
Lake Level
Power Tunnel Discharge
Total Head Loss
Head Loss Coeff.
3
EL1080
2079 ds
145.3 ft
33.62
1
El.l180
771 cfs
26.9 ft
45.20
3
El.ll90 .6
2184 cfs
160.5 ft
33.63
2
El.l180
1505 cfs
80.4 ft
35.50
It was noted that the head loss coefficient varies with number of units
in operation and is almost constant for the entire range of reservoir
elevations.
00629C-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 9
2.3 DESIGN PRESSURE
Transient analyses have been performed to determine the maximum and
minimum pressure in the power conduit and turbine intake: during_ load
rejection and acceptance. The study further identified the most adverse
combination of operating conditions pr1.or to load rejection/ acceptance
leading to the extreme rressure values:
Static Head
Normal Design Pressure
Emergency Pressure
TABLE 4
CONTROLLING PRESSURE HEADS
feet psi
1175 510
1470 637
1950 845
Extreme Emergency Pressure 2350 1020
The above pressures are defined as follows:
PCT of PCT of
Static Design
Head Head
100 80
125 100
166 133
200 160
a. Normal Design Pressure includes maximum static head plus pressure
rise due to the normal operation, without malfunctioning of any
protective device or equipment component. The wor.st case would be a
simultaneous load rejection of three units, operating at full flow
at maximum reservoir elevation (El. 1190.6), resulting from a loss
of transmission lines. Based on the results from the transient
analysis the internal design pressure for normal operating condi-
tions was established as 1470 feet of water column .025 percent of I ·
static head). Corresponding needle closing rate= wouLd be approxi-
mately 85 seconds.
00629C-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
NOTE:
Page 10
During execution of the Transient Analysis Study the Design
Pressure was reduced from 1650 feet (715 psi) to 1470 feet (637
psi). To facilitate this change, the turbine needle closing
rate had to be extended from 60 to 85 seconds. This longer
closing time would not objectionably impair regulation charac-
teristics of the turbines, however, the reduction of the design
pres sure would bring over $860,000 worth of savings of the
penstock and liner steel.
b. Emergency Pressure includes normal operating conditions plus such
events as malfunctioning of the control system allowing simultaneous
needle valve closure, within 21/a seconds at maximum rate, of three
units operating with nx jets at the flood reservoir level. The
maximum allowable pressure for this category was established as 1950
feet (166 percent of static head).
c. Extreme Emergency Pressure includes malfunctioning of the control
system in the most adverse manner, such as instantaneous loss of
governor oil pressure, broken needle stem on one or more Pelton
jets, or auto oscillations due to equipment and interrelated systems
associated with the power conduit. The maximum allowable pressure
for this category will be 2350 feet (double the static head).
The spiral distributor, spherical valve, and other pressure vessels
will be designed by the equipment manufacturer using its design
criteria and approach methodology for the above pressure conditions.
Ninety six percent of Yield Tensile Strength (YTS) should not be
exceeded 1n any equipment component subjected to the Extreme
Emergency Pressure of 1020 psi.
3.0 OPERATION
3.1 OPERATION OF UNITS
The turbine-generator units should be operated with minimum load changes,
especially load acceptance, due to the long opening rate required due to
the extremely long power conduit. Under normal conditions the units will
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 11
.be started by an automatic sequence which will ensure orderly
start-up/shut-down and speed adjustment with slow needle valve motion,
thus minimizing pressure variation in the tunnel. From time to time one
or more units may experience a load rejection, full or partial, depending
on circumstances. Simultaneous load rejection of all three units may
occur for various possible system/plant conditions. ·Under normal condi-
tions the effects of load rejection will be minimized by rapid closure of
the deflectors with the needle valves to follow. If one or more needle
valves on one unit fail to close, the corresponding spherical valve will
close. This arrangement allows the remaining unit(s) to operate without
any restriction.
In the event that one or more needle valves have failed and the spherical
valve fails to close, the high pressure gate in the power intake shaft
would have to be closed. Initiation of gate closure will automatically
start the shutdown of all operating units.
3.2 REGULATION OF TURBINES
The turbines will have· two means of regulation and closure: slowly
operating needle valves and fast operating deflectors. The design closing
and opening rate for the needle valves is 85 and 60 seconds respectively
for the three-unit arrangement. Both closing and opening rates for
deflectors are 1.5 seconds. This combination is specifically suitable for
a long power conduit where transient pressure may be a problem. In the
event of a load rejection the deflectors deflect the jet streams away
from the runner without changing the tunnel discharge and creating a
pressure rise. Closure of the needle valves, although completed in a
considerably longer time (85 seconds) than closure of deflectors, produc-
es a pressure rise of approximately 25 percent above the static head when
three units are operating.
3.3 OPERATION OF SPHERICAL VALVES
Each unit will be equipped with a spherical valve located inside the
powerhouse upstream of the turbine intake. The valve will be capable of
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 12
~mergency closure under full flow conditions. The preliminary
closing/opening rate of the valve is 120 seconds. This total closing time
could be reduced if two speeds are used. The. valve will close on an
emergency close and overspeed signal. The spherical valve will be used to
isolate the unit for maintenance or in case of failure of one or more
needle valves. Closure of a spherical valve against flow would also
produce pressure rise. The closure rate for the valves will be so
designed and adjusted that the pressure rise caused by the valve closure.
will not exceed that caused by the combined needle valve closure.
During repairs and maintenance the unit will be shut down, the spherical
valve closed, upstream seal engaged and locked, and the turbine manifold
dewatered. Access to the inside of the turbine manifold will be possible
through a mandoor in the valve closure section between the valve and
turbine intake section.
3.4 SLUICING THROUGH THE TURBINES
The turbines will be able to operate within the lake level range from El.
1080 to El. 1190.6. In case of extreme emergency, the power tunnel may
be used to lower the lake level to El. 1060. If· the equipment is
operational the units will operate on-line and generate power. For this
type of operation the needle closing and opening times as well as
~pherical valve opening and closing times must be considerably extended
over the presently proposed values to prevent subatmospheric pressure tn
the upper tunnel bend. The tunnel flow might have to be reduced to
prevent vortices at the intake.
Plant Operations Manual.
This issue must be addressed in the
In case of damage to the electrical apparatus the units may be able to
spin but can not be synchronized and no power can be generated. Sluicing
with the runner at standstill, generator brakes applied, deflectors in
fully "cut-in" position, and the needle valves open as needed is pre-
ferred over running the unit at runaway conditions.· Small to -mode-rate
damage to the turbine, such as erosion to the turbine pit walls as well
as vibration damage to the deflector operating system, is expected. This
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 13
type of sluicing operation should therefore b~ used only to prevent
damage of large magnitude such as failure of the dam and should be
limited to the minimum.
3.5 FLOOD OPERATION
Turbine operation will be available during high flood flows, which result
in raising the reservoir level above El. 1180, without limitation.
4.0 DESIGN CONSIDERATIONS
4.1 HYDRAULIC TURBINES
4 .1.1 Runner
Runners will be made of 13-4 type stainless steel. They will be one piece
casting. The foundry chosen to cast the runner must demonstrate experi-
ence with similar.work. The finished runners will be balanced statically
and dynamically at a reduced speed.
The runner will be removable from below to facilitate fast repa1rs. An
access gallery and a special cart will be required. One spare runner
will be provided for the project.
4.1.2 Shaft -Bearing System
A three bearing shaft system will be provided for each unit: turbine
guide, generator guide, and combination guide/thrust bearing on the top
of generator. There is virtually no vertical hydraulic thrust so the
thrust bearing has to support weight of rotating parts only. All bearings
will be oil lubricated, the oil will be self-circulated. A high pressure
oil pump will be provided for the start-up of the combination bearing.
Coolers for the combination and turbine guide bearings will be-provided.
The turbine guide bearing will be sized to support the radial forces
created by a simultaneous operation of three adjacent jets. For this
00629C-1580072-D1 PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
r
Page 14
reason a bearing cooler must be provided. The cooler will be used rarely.
For the purpose of sizing the cooling system, 30 gpm is assumed as the
maximum cooling water requirement for the turbine guide bearing.
The same brand and type of oil will be used for the turbine, governor,
and spherical valve. A portable on-line oil purifier will be provided to
serve all these systems. Filling and drainage connections will be
provided.
4.1.3 Shaft Seal
A shaft seal is required for the operation when the tailrace chamber is
pressurized. The commonly used carbon ring seals are not suitable for
application at The Bradley Lake Project due to glacial flour suspended ~n
water. The particles may be highly abrasive and cause rapid wear of
stationary and moving seal components in contact.
A non-contact type seal, such as labyrinth or cylindrical type without
water injection, will be specified. If required by the manufacturer,
cooling water in the amount of approximately 10 gpm will be available
from the station service system.
4.1.4 Tailrace Depression System
A tailrace depression system will be provided to maintain the water level
in the turbine chamber at El. 6.0, should the tide rise above El. 6.0.
This is to maintain a minimum required distance of 9 feet between the
runner centerline and the water level in the chamber. Operation of the
system will be infrequent, not exceeding 2.5 percent of the time. The
system will be designed for the maximum tailrace chamber pressure of 7.0
feet of water column, corresponding to a tailwater level of approximately
El. 13.4. It will allow two foot waves (or the storm surge) on the top of
the highest tide (El. 11.37), or five foot waves plus two foot storm
surge on the top of the maximum tailrace operating level (E1.6.0)-. It is
recognized that the fans will not be able to suppress completely surges
in the tailrace chamber caused by the waves in the tailrace. Should the
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES.
Page 15
oscillation of the water level in the tailrace chamber create intolerable
power swings, the unit.will be operated at a lower load or shut down. In
the case that the total of the tailrace level and waves exceeds El. 13.4,
the unit will be shut down.
The tailrace depression system will consist of two fans, one fan serving
each turbine. The system will allow admission of outside air when the
depression system is not in operation.
The system will be controlled automatically •. When the level in the
tailrace chamber reaches El. 6.0, the corresponding compressor will be
started~ A modulating valve will maintain the water level 1.n the
tailrace chamber at El. 6.0 •.
4.1.5 Cooling Water System
The turbine manufacturer will provide suitable means of collecting fresh
water discharged from the turbines and storing it in a sump located
between Units No. 1 and 2. The. theoretical minimum amount of water
required for each turbine in operation is about 300 gpm.
The collecting device will be located at high as possible to minimize
intrusion of brackish water into the cooling system and to assure re-
quired water quantity in the fresh water sump. Preferred.eleva:tion of the
collecting device is at El. 15.0. The lowest acceptable elevation is at
El. 11.5.
The Specification will call for turbine guaranteed efficiency including a
water collecting device. A model development study will be conducted on a
fully or closely homologous model to determine the elevation, type, and
size of the water collecting device. It is believed that one or more
troughs can be located between elevations El. 11.5 and 15.0 and deliver
the maximum flow of 530 gpm for two turbines at all loads and heads.
Under normal conditions, no ingression of brackish water into-the system
is expected when troughs are located within this range •
00629C-1580072-D1 . PERFORMANCE CRITERIA/TURBINES~ GOVERNORS, VALVES
Page 16
~hould adjustment of the quantity of water collected by the troughs be
necessary, the troughs can be made smaller or larger, their number
increased or reduced, or their elevation raised or lowered as the case
may be providing that loss of turbine efficiency will-not take place. In
any case the troughs must remain above El. 6.0 (higher high tide) to
limit frequency of potential salt water intrusion and to satisfy equation
(1) for any operating conditions.
A two-circuit closed loop cooling water system with heat exchangers will
be provided. Circulating water pumps will pump water from the sump
through a heat exchanger and discharge it to the tailrace. Component
cooling water pumps serving a closed component cooling water loop will
circulate fresh water through the heat exchanger and the equipment
coolers.
4.1.6 Spiral Distributor
The spiral distributor will be of steel welded construction, and will be
designed by the turbine manufacturer to withstand the internal pressure
as per TABLE 4 without contribution from the surrounding concrete.
Branches with flanges will be provided to receive the needle valves. The
distributor will be shipped in sections and assembled by welding ~n the
field. Connection by flanges will be allowed as an alternative.
After assembly and pr~or to concreting, each distributor will be pressure
tested to 150 percent of normal design pressure (1.5 x 637 = 956 psi). A
bulkhead must be provided for the turbine inlet flange since the pressure
test will be carried out without the spherical valve. Bulkheads should
also be used to seal the branches, rather than use the needle valves.
The distributor will be pressurized during concreting to full static head
(1175 feet).
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS~ VALVES
Page 17
4.1.7 Runner Chamber
The runner chamber will be of hexagonal shape, a steel liner, fully
embeded in concrete will be provided. Blackouts will· be provided in the
first stage concrete for· installa,tion of the liner •. The liner will be
heavily ribbed and anchored to the concrete. It will be designed to
withstand a hydrostatic pressure of 50 feet acting from the tailrace and
resulting from the most adverse combination of tide, . waves, storm, and
tsunami.
4.1.8 Needle Valves
Needfe valves of built in straight flow type will be mounted on the pipes
branchin~ off the spiral distributor. Each valve will hav~ a built in
servomotor and a control unit mounted on the turbine cover. Needle valve
servomotors will be oil to open and oil to close. The needle valves will
be designed to close in case of oil pressure loss. Pressure oil will be
distributed from the governor accumulator tank to the individual control
units and used oil will be .Piped b~ck to the governor oil sump. Leakage
oil from the servomotor seals will be collected to the powerhouse dirty
water sump.
The needles will be operated symmetrically by the governor in a preset
sequence. The number of jets in operation wi.ll depend on the toad and
will also be automatically selected by the governor. Needles in steady
state operation will be in_ the same opening position resulting in the
s·ame discharge and diameter of the water jet s.tream. Needle closing and
opening times will be adjustable within the range of 60 to 300 seconds.
Closing and opening rates to be used for operation of two units are
expected to be the same, in the order of 60 seconds.
4.1.9 Deflectors
Deflectors will be operated by a single servomotor via a common linkage.
Deflector control will be oil to open and oil to close. The deflectors
will have opening and closing rate adjustable within 1.5 to 5 seconds.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
1
Page 18
4.1.10 Instrumentation
The ultrasonic method of measurement will be used for continuous flow
monitoring. A four paths system supplied by a presele-cted manufacturer
will be specified. Two measurement sections will be provided for each
unit.
Four piezometers for head measurement installed at the turbine inlet will
be provided for each unit. All piezometer piping will be stainless steel
tubing and will terminate above El. 21.0.
4.2 SPHERICAL VALVES
4.2.1 Valve Body
The spherical valve body will be a combination of cast and fabricated
construction. The body will be split in halves, flanged and connected by
bolts. The valve body will be attached by suitable bolts to the base
plate. Slotted holes will be provided to allow axial movement of the
valve up to 3/4 inch.
4.2.2 Connecting Pipes
The spherical valve will be rigidly connected to the penstock on the
upstream side. The valve manufacturer will provide a short length pipe
extension on the upstream side made of A710 steel, the same material as
the penstock. The pipe will have a flange for connection to the upstream
face of the valve and will be welded to the downstream end of the
penstock. The length of the pipe will include allowance for trimming. The
valve manufacturer will be responsible for the design of the weld between
the extension pipe and the penstock. The weld will be performed by the
Powerhouse Contractor. The penstock is anchored approximately 40 feet
upstream of the valve. The portion of the penstock downstream of the
anchor will be allowed to expand freely which will result in an axial
movement of the valve, calculated for the exposed pipe, extreme emergency
penstock pressure, and the temperature extremes, to be 1/2 inch.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 19
A closure section will be flanged to the downstream face of the valve and
will have a high pressure sliding type coupling on the turbine-side. The
closure section on the downstream side of the spherical valve will
accommodate the ultrasonic system for flow measurement.
4.2.3 By-Pass System
A by-pass system will be provided to equalize pressure on both sides of
the valve prior to opening. An internal by-pass conduit or an external
system tapped between valve seals will be specified to minimize exposed
pressure piping. The by-pass valve will be operated hydraulically, using
governor oil. The valve will have a strong closing tendency and a spring
will be provided to assure that the by-pass valve will close on loss of
governor pressure.
4.2.4 Oil Pressure System
The valve plug will be operated by one single action, oil to open
counter-weight to· close servomotor. Governor oil will be used to open
the valve. In case of governor oil pressure loss the counter-weight will
safely close the valve. An anti-slamming device .will be provided in the.
servomotor cylinder.
4.2.5 Valve Seals
The downstream operating seal of the valve will be fixed metal-to-metal
(stainless steel to copper alloy) type. It will close and seal by
eccentric motion of the ·valve rotor. No moveable par-ts or operating
media (oil, water) will be used. It is believed that· this arrangement
will eliminate the possibility of auto-oscilation in the power tunnel.
The upstream seal will be used for maintenance only, will be manually
operated with the valve closed, and will be water operated. The mainte-
nance seal will be equipped with a manually activated mechanical device
to lock the seal in engaged position to maximize safety during the
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES, GOVERNORS, VALVES
Page 20
maintenance period when the spiral distributor is dewatered and the
mandoor is open.
00629C-1580072-Dl PERFORMANCE CRITERIA/TURBINES~ GOVERNORS, VALVES
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J.O. No. 15800
HYDRAULIC DESIGN CRITERIA
TAILRACE
REVISION: 1
DATE: FEBRUARY 10, 1987
TABLE OF CONTENTS
SECTION TITLE PAGE NO.
1.0 DESCRIPTION AND OBJECTIVES 1
2.0 OPERATION 2
DESIGN CONSIDERATIONS 3
4.0 DESIGN CRITERIA AND PARAMETERS 3
1-262-JW HYDRAULIC DESIGN CRITERIA:TAILRACE
Page 1
1.0 DESCRIPTION AND OBJECTIVES
Background
The turbine chamber acts as a body to receive water falling from the
Pelton wheel turbine buckets. Data from various turbine manufacturers
show that the highest water level for full load. operation should be
about 9 feet below the runner centerline, or at elevation +6 Bradley
Project Datum, after establishing the runner centerline (see attached
Table 1 for datum relationships). The manufacturers also recommend
that the bottom of the turbine chamber and tailrace be 21 feet below
the runner centerline, i.e. elevation -6.0. These values are used for
the Project design.
Based on the Powerhouse Setting economic study Action Task No. 1 and
Hydraulic Calculation No. H-009, the runner centerline has been set at
elevation 15. The normal maximum tide elevation is at elevation 6. 0,
the highest tailrace allowable level for full load turbine operation.
Tide levels above elevation +6.0 have only a 2.5% exceedance level
(see attached exceedance levels in section 4. 0 and Figure 1) . For
these high tides the water level in the turbine chamber must be
reduced by the air depression system to enable the full load turbine
operation.
1-262~Jw HYDRAULIC DESIGN CRITERIA:TAILRACE
Page 2
Objectives
The tailrace, which is the channel area downstream of the powerhouse,
will be designed to collect the water from the turbines and transport
it away from the powerhouse to Kachemak Bay with minimal backwater
effect at the powerhouse.
Additionally, the tailrace discharge must be designed to minimize ice
formation during freezing conditions. Design considerations for
prevention of ice formation in the tailrace channel shall include a
relatively narrow top width, a moderate flow depth across this width,
and a fairly swift velocity.
Geotechnical Restraints
The tailrace will be excavated i·n the tidal mud fl,ats, with limited
bedrock excavation near the powerhouse.
The sides and bottoms of the basin in the· mudflats will require
protection against uplift from underlying sands which are under
artesian pressures. This protection entails riprapping, sand drains,
or otherwise protecting the entire basin side slopes and bottom. This
treatment will be addressed in the Geotechnical Design Criteria.
1-262-JW HYDRAULIC DESIGN .CRITERIA:TAILRACE
Page 3
2. 0 OPERATION
A maximum of 1500 cfs of water will pass through the two turbines and
flow to the tailrace. Turbulent water discharging into the tailrace
will be diffused across the 90 ft wide channel adjacent to the
powerhouse, slowing its velocity in the process. The channel then
spreads out gradually' while the channel bottom elevation rises, until
it is 176 feet wide. At maximum flow the depth of water is 2.15 feet.
The channel conveys water with a velocity of 3. 8 fps and a depth of
2.15 feet until reaching the slough· where the channel ends. The
slough will receive all the tailrace water beyond this area.
3.0 DESIGN CONSIDERATIONS
The tailrace is to be sized for 2 unit operation with a maximum
combined turbine flow of 1500 cfs.
Starting at the downstream edge of the powerhouse from Station 0+00 to
0+40, the tailrace will have a basin width of 90 feet, excavated to
elevation -6 adjacent to the downstream edge of the powerhouse as
shown on Figure 2. Since it is believed that this section of the
tailrace will be .entirely excavated in rock, no riprap lining is
required.
From Station 0+40 the tailrace will slope upward from elevation -6 to
elevation 3.5 at a bottom slope of 18 Horiz:1 Vert. The tailrace
bottom sides flare at an angle of 14° until a width of 176 feet is
1-262-JW HYDRAULIC DESIGN CRITERIA:TAILRACE
Page 4
obtained. The tailrace side slopes are to be excavated at 4 Horiz: 1
Vert slope. The top of the sides of the tailrace in the section will
be raised to elevation 8.0, Figure 3. Since this section of tailrace
will be excavated in tidal soils underlaiden by a zone of sand which
is subject to confined groundwater pressures, drains and riprap
overlayment is required. The actual engineering characteristics of
the sand drains and riprap are addressed in the Geotechnical Design
Criteria. The end width of the channel shall be extended downstream
with the bottom fixed at elevation 3.5, until the tailrace connects·
with a natural slough channel, about 900 feet away. Since this
section of the tailrace is relatively shallow (0 .5 to 2.5 feet deep)
and the velocities are 3 to 4 fps, the channel will be left unlined.
No special side slope treatment will be required along this channel
length.
4.0 DESIGN CRITERIA AND PARAMETERS
Bradley Project
Tidal Information Datum
High Tide plus Waves (5 ft) El. 16.3
High Tide plus Storm Surge El. 13.3
High Tide at Project Elevation El. 11 -37
Mean Higher High Water Elevation El. 4.78
Mean Sea Level Elevation El. -4.02
Mean Lower Low Water Elevation El. -13.63
Lowest Tide at Project El. -19.63
1-262-JW HYDRAULIC DESIGN CRITERIA:TAILRACE
Maximum Tide Level for Operation El.
of Pelton Turbine without the
depression system operating
in turbine chamber
Water Surface Elevation at Channel El.
at Peak Operation 211 feet from
Powerhouse
Backwater at Powerhouse during Pe~ El.
Operation
TIDE EXCEEDANCE CURVE
PERCENT
EXCEEDANCE
TIDE ELEVATION (FT)
PROJECT DATUM
100%
99%
98%
95%
90%
80%
70%
60%
50%
40%
30%
20%
10%
5%
2%
1%
O%
Shown in Figure 1
-19.6
-17.0
-16.0
-14.3
-12.6
-10.2
-8.0
-5.8
-4.0
2.2
-0.4
1.4
3. 7 .
5.0
6.4
6.8
11.4
Page 5
6.0
5.65
5.92
Size of Basin 90 feet wide at Powerhouse to 40
feet from the Powerhouse
176 feet wide 211 feet from the
powerhouse
Finish Elevation -6.0 feet at Powerhouse
+3.5 at beginning of Channel
1-262-JW HYDRAULIC DESIGN CRITERIA:TAILRACE
Bottom Slope
Maximum Discharge (2 units)
Maximum Velocity in
the Tailrace
Page 6
18 Horiz: 1 Vert
1500 cfs
3 to 4 fps
Basin Lining -riprap
thickness
to be determined by Geotechnical
Division
Mannings nnn factor for
riprapped basin
Mannings nnn factor for
channel excavated in
0.04
tidal silt 0.02
Depth at channel outlet 2 to 2.5 ft
Velocity at channel outlet 3. 5 to 4. 5 fps
1-262-JW · HYDRAULIC DESIGN CRITERIA:TAILRACE
Page 7
TABLE 1
RELATIONSHIP OF VERTICAL DATUMS
Bear Cove Bear Cove Bradley
MLLW MSL Project
Datum Datum Datum
HT 25.0 15.39 11.37
MHHW 18.41 8.80 4.78
MHW 17.60 7.99 3-97
Project
Datum 13.63 4.02 0.00
Origin
(assumed)
MSL 9.61 0.00 -4.02
MLW 1.61 -8.00 -12.02
MLLW 0.00 -9.61 -13.63
LT -6.0 -15.61 -19.63
1-262-JW HYDRAULIC DESIGN CRITERIA:TAILRACE
I
I I I I I I I I I I I I I
BEAR COVE 1 KACHEMAK BAY 1 ALASKA
25 HT=11.37
I~ ,.....,
,....., 20 ,_ MHHW =18.41 ~ -.;;;::::::;: ~ 2-tv1HHW = 1.78 3 ~ ~ :::> -1-MHW = 17.6 ~ f:::::: HHW ( 24 HOURS) ..__ -MHW =3.97 _j "' ~ t--c§-2 15 "' --~ z ....__, t---t--0 ~ ..__ z
...... ..__ u o--10 -MSL = 9.6 ....... HW (12 HOURS -~ w------= tv1 S L = -4.02 -r-
""
> ._LL
I I I
J w 0 g'-J ~ _j 0::: w 5 ~~HOURLY w o._-_j w ~ w >-w f-MLLW 0 w_ MLLW = -13.67 o--0 """ ..__ _j
~ 0 ..__
<!
-5 .......... 0::: en-'-J
-10
0.01 0.1 0.5 2 5 10 20 3040 60 80 90 95 98 99 99.8 99.9 99.99
o/o EXCEEDENCE
ALASKA POWER AUTHORITY CUMULATIVE PROBABILITY DISTRIBUTION
BRADLEY LAKE HYDROELECTRIC PROJECT FOR TIDE EXCEEDING LEVEL GIVEN
AN OBSERVATION LENGTH KENAI PENINSULA BOROUGH,ALASKA FIGURE 1
0
0
0
L{)
(\j
(Y)
w
N2130000
·-~·
EL +3.5
1 II= 200 1
TAILRACE AT POWERHOUSE
FIGURE 2
fUNIT # 1 f UNIT #2
I POWERHOUSE I
STA 0+00
STA0+40
EL+8
STA
2+11
..
OJ
60 1
EL -6
90 1
176 I
EL + 3.5
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
KENAI PENINSULA BOROUGH,ALASKA .
EL+S
11=4011
GEOMETRY OF
TAILRACE
FIGURE 3
5197R/0205R/CM
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J. 0. No. 15800
MIDDLE FORK DIVERSION
HYDRAULIC DESIGN CRITERIA
REVISION: 1
DATE: July 20, 1988
STONE & WEBSTER ENGINEERING CORPORATION
HYDRAULIC DESIGN CRITERIA
MIDDLE FORK DIVERSION
Page 1
1 . 0 DESCRIPTION
The Middle Fork Diversion is located approximately one mile north of
Bradley Lake in an adjacent drainage at elevation 2160 on the Middle
Fork Tributary of the Bradley River. The Diversion will consist of a
small intake basin and two reaches of open channel approximately 770
feet ·and 480 feet long, separated by a stilling basin which is located
in a natural bog area, all of which will be established by
excavation. Refer to Figure 1, Area Plan. The Diversion will convey
water from the Middle Fork of the Bradley River to Marmot Creek, a
tributary to Bradley Lake, and wil1 operate in all seasons.
Access to the Middle Fork Diversion during construction will be by
helicopters, which will be used to transport personnel, material, and
construction equipment. Overland access will not be permitted.
2. 0 CRITERIA
2.1 DESIGN FLOW
The design flow is 800 cfs, which has a recurrence interval of 75
years based on analysis of peak average daily flows.
2.2 GRADIENT AND FLOW CHARACTERISTICS
In both the upper and lower reaches, a gradient shall be maintained
such that subcritical flow is established, the exception being for a
short distance prior to the stilling basin at the natural bog area.
There supercri tical flow will be acceptable. A Manning's "n" factor
of 0.040 shall be used for flow calculations.
2.3 CHANNEL CROSS-SECTION
Figure 2 shows the channel cross-section to be used for the case of ·
channel excavation in rock and overburden, and also for the case of
channel excavation in overburden alone. The overburden slope of 2H:lV
may be adjusted to 3H:lV as required during construction.
5197R/0205R/CM HYDRAULIC DESIGN CRITERIA
MIDDLE FORK DIVERSION
INTAKE BASIN
MANDATORY
WASTE FILL
AREA 2 -------'
TO MARMOT CREEK
EXISTING DRAINAGE'-.c-.----
STILLING BASIN
OPEN CHANNEL
(NTS)
AREA PLAN
FIGURE l
Page 2
HYDRAULIC DESIGN CRITERIA
MIDDLE FORK DIVERSION
--
ROCK
t 1-10' -i
MIN
TYPICAL
CHANNEL EXCAVATION
IN ROCK&. OVERBURDEN
(NTS)
LOOKING UPSTREAM
~
I
I
Page 3
.~OVERBURDEN
~ ~6~--~~-t---,r:;-2;1:;u---
2'~ , I
MIN
TYPICAL
·cHANNEL EXCAVATION
IN OVERBURDEN
(NTS)
LOOKING UPSTREAM
CHANNEL CROSS SECTION
FIGURE -2---
HYDRABLrc DESIGN CRITERIA
f.HDDLE :?ORK DIVERSION
-"---· .-_:::;;._,:~~
4481R/CM
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J.O. NO. 15800
NUKA DIVERSION
HYDRAULIC DESIGN CRITERIA
REVISION: 0
DATE: July 5, 1988
STONE & WEBSTER ENGINEERING CORPORATION
HYDRAULIC DESIGN CRITERIA/
NUKA DIVERSION
NUKA DIVERSION
HYDRAULIC DESIGN CRITERIA
TABLE OF CONTENTS
Section Section Title
1.0 DESCRIPTION AND OBJECTIVE
2.0 DESIGN CONSIDERATIONS
3.0 .DESIGN CRITERIA AND PARAMETERS
Attachment A Contract Between Alaska· Power Authority
and the Department of the Interior
Attachment B Area Plan
Attachment C Letter' from the Alaska Power Authority
to the Park·Service Concerning the
Nuka Divers.ion Design Concept
Attachment D National Park Service Letter of Approval
Page No.
1
1
2
4
10
11
15
4481R/CM HYDRAULIC DESIGN CRITERIA/
NUKA DIVERSION
Page 1
1.0 DESCRIPTION AND OBJECTIVE
Glacial melt forms a pond called Nuka Pool at the terminus of the Nuka
Glacier. Nuka Pool lies on the divide between two drainages, discharging
water both into the Upper Bradley River and into the Nuka River. Water
discharged into the Upper Bradley River flows to Bradley Lake and that
which is discharged into the Nuka River flows to the Kenai Fjords National
Park.
The purpose of the Nuka Diversion improvements is to cause the glacial melt
water flowing through the Nuka Pool to flow into the Upper Bradley River,
except for an initial increment of flow which must be provided to the Nuka
River in accordance with the June 1986 Contract between the Alaska:~ Power--: -:-:_-
Authority and the U.S. Department of the Interior. A copy of the Contract
is provided as Attachment A on Page 4. Per this Contract, the design must
assure that the first 5 cfs of available flow goes to the Nuka River. Flow
in excess of 5 cfs will be diverted to the Upper Bradley River. After a 10
year period, the amount of required flow release to the Nuka River may be
reevaluated and possibly increased to as much as 10 cfs.
2.0 DESIGN CONSIDERATIONS
An earth-fill dike and gabion structure will be designed to control flow to
the Nuka River. The flow will be through a steel pipe within the gabion
structure. At the Upper Bradley River end of the Nuka Pool, the flow to
the Upper Bradley River will be over a weir resulting from modifications to
an existing natural rock weir. Figure 1, Area Plan, Attachment B on Page
10, shows the locations of these improvements. Attachment C on Page 11
provides an explanation of the Nuka Diversion design concept.
The design of the weir length and crest elevation at the Upper Bradley
River end of the Nuka Pool and the design of the discharge pipe size and
length at the Nuka River end of the Nuka Pool will be developed so as to
accomplish the following:
4481R/CM HYDRAULIC DESIGN CRITERIA/
NUKA DIVERS ION
Page 2
• There will be no flow over the Bradley-side weir until 5 cfs flow
is being discharged through the Nuka-side pipe.
• The crest of the Bradley-side weir will be set at an elevation
such that when the Nuka Pool has risen to a height providing
sufficient head to deliver 5 cfs through the Nuka-side pipe, flow
will commence over the weir.
• The weir will be of sufficient length so as to prevent staging up
of the pool more than two feet in the case of a total discharge
of 500 cfs.
• Regulating valves will not be used; only shut-off hand-operated
gates (on-off) will be used.
• Flow in excess of the required 5 cfs through the Nuka-side pipe
will be minimized.
A second pipe, identical to the one designed to deliver the 5 cfs to the
Nuka River will be provided and blocked off. This second pipe will then be
available, should the required flow release to the Nuka River be increased
at the end of 10 years, as stipulated in the Contract between APA and the
Department of the Interior.
3.0 DESIGN CRITERIA AND PARAMETERS
• Nuka-Side Dike
See Part 2.0 for a basic description of the dike. The pipes will be
standard steel of a size no smaller than 12 inches. They will contain
no thawing devices, but will be located at a depth of submergence
great enough to prevent freezing. The pipes will be placed level.
The excavated maximum channel bottom elevation will be one foot lower
than the pipe inverts locally and will be sloped up no steeper than
5H:lV away from the pipes.
4481R/CM HYDRAULIC DESIGN CRITERIA/
NUKA DIVERSION
Page 3
The pipes will be sized to allow 5 cfs each to pass before any water
spills over the Bradley-side weir. One pipe will be normally shut.
Open/close shear ·gates, hand-operable from above water, will be
provided at the upstream end of the pipes.
\ Construction will include any necessary excavation just downstream of
the gabion structure in the Nuka River sufficient to lower the
tailwater on the pipes to such a level as is necessary to achieve the
required minimum design flow.
A membrane liner across the gabion structure will be used to reduce
dike seepage.
The minimum dike crest elevation will not be less than 3 feet higher
than the weir crest elevation of the weir at the Bradley River end of
the Nuka Pool.
• Bradley-Side We.ir
The natural rock weir existing at the Bradley River end of the Nuka
Pool will be improved as follows:
A -long broad-crested. weir of uniform crest elevation will be-obtained
by carefully controlled removal of existing rock and/or placement of a
concrete cap. The crest width will not exceed 12 feet. The crest
length and elevation setting will be in accordance with Part -2. 0
above. The minimum differential between the crest elevation and the
bottom elevation adjacent to the weir will be 1.5 feet.
4481R/CM HYDRAULIC DESIGN CRITERIA/
NUKA DIVERSION
ATTACHMENT A
4481R/CM
Page 4
HYDRAULIC DESIGN CRITERIA/
NUKA DIVERSION
Page 5
CONTRACT.
This contract between the Alaska Power Authority, a, public
corporation of the State of Alaska, (herein "APA") and the
Department of the Interior (herein "DOI"), executed this 16th day
of JUNE , 1986, .set.s forth the mutual agreements, rights,
responsibilities and determinations of the parties regarding the
use of the flow of waters from the Nuk~ Glacier into the N~ka
River, a river partially contained within the boundaries of Kenai
Fjords National Park (herein "Park"), and the diversion of Nuka
River glacial headwaters upstream of the_Park boundary by the.APA
for ~urposes of hydroelectric power generation by the Bra~ley Lake
Project (herein "Project").
Whereas, the APA is ·proposing to commence construction of
the Project, having received and accepted all federal and state
permits and. licenses necessary to initiate construction; and
Whereas, the resolution af the water uses of the parties in
the Nuka River is important to the economic feasibility of the .:..-
Project; and
Whereas, the Bradley Lake Power S'ite Classification Order
No. 436 which was issued by the Interior D~partment in 1955, and
subsequent actions of Congress, reserved_, in the opinion of the
APA, all lands described in the order, including the area of Nuka
rive.r glacial headwaters, _for power ~ite purposes; and
Whereas, Kenai Fjords National p'ark w~s established by
Section 201 of the Alaska National Interest Lands Conservation Act
of December 2, 1980, 16 ti.s.c. 410hh, thereby establishing in the
opinion of DOI, a federal reserved wate~ right for the Park to
that amount of water from the Nuka glacier headwaters reasonably
necessary to fulfill the primary purposes of the Park; and
Whereas, the Nuka.Glacier pool is.an intermittent headwater
source to the Nuka River of a shifting hydrologic nature, which
arises outside of the Park boundary; and
Whereas, these waters originati~g outside ihe Park boundary
contribute to· the physical features within the Park; and.
Whereas, it is-important to the National Park Service (NPS)
to receive releases of water at the Nuka River diversion structure
rather than a guaranteed flow.at the Park boundary to ensure
receipt of-sufficient gla~ial headwater flows into the Nuk~ River;
and
Whereas, the parties wish to resolve mutually the water use .
issues without litigation, in part because water rights litigation
is time consuming as well as costly; and ·
Page 6
Whereas, the parties consider the problems associated with
establishing the water use agreement for the Park and APA as
unique to this Project only; and
Whereas, 'th·e parties do not consider this Contract as
preceden.tial in possible other future water issues between NPS,
and APA, and consider and agree that the Contract is inadmissible
in any future litigation or discussioi over water rights in
Alaska, except for the Nuka River.
1.
Now, therefore, the APA and DOI agree as follows:
The APA agrees that: ,.
(a) It will construct a diversion stru~tur~(s) outside the
boundary of the Park at the outlets of the Nuka Glacier Pool,
·and will maintain and operate the structure(s) at no cost to
the United States.
(bf NO Park lands will be used during construction·,. op_eration
or maintenande of the diversion structure(s) except as
necessary to measure Nuka river flows. 0 .:.--
(c) ~The structure(s) will be constructed so as to guarantee
t.he release of a minimum weekly average flow of 5 cubic feet
per second of water, as long as releases from the diversion
structure(s) do not go belo~ a minimum daily average of 3
c.fs,. into the Nuka River measured at the NUka River
diversion structure(s) site from June 1 through September 30
annually~ to the extent adequate water is available in the
Nuka glacier pool to provide such releases withotit pumping or
redesign of the diversion structure(s).'
(d) As soon as the diversion structur~(s) is in place, the
minimum release guarantee dontained in this agreement will be
implemented. The APA will notify the NPS at the time that
Nuka Glacier flows commence being diverted. During
construction of the diversion structure(s) releases will be
made into the· Nuka river which, measured at the Nuka River
div~rsion structur~(s) site, will not be less than 5 cfs on a
weekly average basis to the extent that adequate water is
natu~ally available in the Nuka glacier pool to·reasonably
provide such releases.
(e) If the Ptoject is abandoned or ceases to g~nerate power
for 8 consecutive years after the structure has been
completed, natural flows will be reestablished-in the Nuka
River by adjustment.or removal of the $tructure(s). ·
Provided, however, if APA decides to recommence the
gen~ration of power, this agreement ~ill be revived and in
full effect.
- 2 -
Page 7
(f) ·It will install a gage at a mutually agreed location at
or near the diversion structure(s) to monitor releases from
the structure(s). The gage installation and operation will
be at no cost to the United· States~ Said gage will be
removed upon abandonment of the Project.
(g) It will amend its water rights application before the
Alaska Department of Natural Resources to reflect the terms
of this contract.
(h) It will survey the Park boundary up to 200 yards on
either side of the Upper Nuka River and post boundary notices
at the Park boundary below the Nuka Diversion, and will make
available NPS-provided Park information to .visitors 'gaining
access to the Park from the Project area.
(i) The DOI will be provided 60 days to review and comment
on the design Specifications of the diversion structure(s).
The APA agrees to consider fully the comments on these plans,
-· and·-respond in writing to ~he comments, setting forth the .
rational basis for why any recommendation was not accepted.·
APA agrees that the diversion structure(s) will be designed·~·
to meet the release requirements provided for in this
contract, including those releases that may be provided by
l(j) and 2(c).
(j) In the event there are waters excess. or .surplus to the
needs of APA, such as spilling or releasing water from the
project unrelated to power generatiori, re~ervoir maintenance
on fisheries releases, APA. agrees to notify DOI that further
water releases are~ available from the diversion structure(s)
and to provide those flows·if request by NPS.
2. The DOI agrees that:
(a) A minimum weekly average release of 5 cfs, as long as
releases from the diversion do not go below a minimum daily
average of 3 cfs, into the Nuka River measured. at the
diversion structure(s) during June 1 through september 30,
annually, to the extent adequate water is available in the
Nuka glacier pool to provide such releases without pumping,
or redesign of the diversion structure(s), is sufficient to
meet the primary purposes for which the Park was established.
(b) It will act consistent with the terms and conditions of
this agreement· in asserting rights to water from the Nuka
glacier headwaters, and will not assert additional water
rights for the Nuka ~lacier headwaters in any wat~r rights
adjudication or other proceeding except as provided in (c) of
this section. Therefore, the APA may rely on this. contract
for bonding, licensing, construction, and operation of the
project.
- 3 -
·Page 8
(c)· over the next 10 years, it may study, at no expense to
the APA, the effects of the flow releases on the Park in
relation to the primary purposes of the Park that are served
by the Nuka Glacier headwaters.
(i) At the end of the 10 year period, if it is
demonstrated that the releases are inadequate to
maintain primary park purposes served by the Nuka
ylacier headwaters, the NPS may propose to the APA an
amended flow release, which proposal will set forth the
rational basis for the amended flow release, and provide
~11 accompanying studies reyarding the necessity for an
amended flow release.
(ii) At the end of the 10 year period, if it is
demonstrated that the release of 5 cfs at the diversion
structure is not necessary to maintain primary Park
purposes served by the Nuka Glacier headwaters, the APA
may propose to the NPS an amended flow release, which
proposal will set forth the rational basi_s for the
amended flow ·release.
(iii) If the parties cannot mutually agree on an
amended flow release within 120 days of the NPS
submission to the APA, the NPS may propose and initiate
a hearing on the record before an administrative law
judge designated by the Secretary. In the event that
.the secretary concludes, upon recommendation of the
·administrative law judge, and based upon the hearing
record, and the preponderance of the evidence, that an
increased release is necessary to maintain the purposes
served by Nuka glacier flows to the Park and will
mitigate or avert significant injury or damage to park
resources served by those purposes, the APA w_i 11 abide
by this decision of the Secretary unless that decision
is reversed by a final order of a court of competent
jurisdiction. Provided, however, the Secretary of the
Interior may not require an increase in the flow release
into the Nuka River to an amount which exceeds a minimum
weekly average flow of 10 cfs, measured at the diversion
structure(s), to the extent adequate water is available
in the Nuka glacier pool to provide such release without
pumpiny or redesign of the diversion structure(s). In
the event that the Secretary concludes, upon
recommendation of the administrative law judge, and
based upon the hearing record 1 and the preponderance of
the evidence, that a release of 5 cfs at the diversion
structure ( s) is· not necessary to maintain the purposes
served by Nuka Glacier flows to the Park, the NPS will
_ abide by the decision of the secretary unless that
--decision is reversed by a final order of a court of
competent jurisdiction.
- 4 -
· l Page 9
3. Geneial Provisions:
(a) This agreement is binding on the parties, their
successors and assigns.
(b)" The obligations of the APA, DOI and United States are
contingent upon the availability of appropriated or other
applicable funds.
(c) This Contract may be executed by the parties in duplicate
originals and the date of the later signature will be the
effective date of the agreement.
(d) This Contract may not be introduced in a court of law,
cited as precedent or used in any future discussion between
the DOI and APA over the water rights of any area in Alaska,
except for the Nuka Rivere
_ Notary: ~ })., i9KG
~c;:.t!i:w&-
. Disttict of Columbicl
My cxm•iasicm espiies April 14, 1981
~PowerAut~ity kk
By: Lee Nunn
Chairman of the Board
Date: June 16, 1986
Department of the Interior
William P. Horn
Assistant Secretary
for Fish and Wildlife
and Parks
Date: ~ \ :;t, n S (c
- 5 -
.. ;_.
.... -"\ -~/ \ _..,. \
'\
\
. \
NUKA
GLACIE-R
Attachment B
'-·-~\
OUTLET WEIR
; ... /-·)
\ l.. i .. .J)
/ )NUKA
I . ·._~:
/ .~ I •
I
I
I
I
Page 10
N.T.S.
AREA PLAN
..._ _____________ FIGURE 1 -...-.
HYDRAULIC DESIGN CRITERIA/ NUKA DIV:CRSIOU
Attachment C
~
Page 11
Steve Cowper. Governor
Alaska Power Authority
May 23, 1988
APA/OTHR/0566
Mr. Boyd Evison
Regional Director
U.S. National Park Service
2525 Gambell Street
Anchorage, Alaska 99503
State of Alaska
Subject: Bradley Lake Hydroelectric Project
Nuka Diversion Design Review
Dear Mr. Evison:
As required by Part 1 (i) of the June 1986 Contract between the Alaska
Power Authority and the Department of the Interior regarding the
diversion of Nuka River glacial headwaters upstream of the Kenai Fjords
National Park, we are providing you with the following design
.information and documents for your review and comment: ·
Item
Drawing No. 15800-FY-147A
Drawing No. 1580Q-FY-147B
Drawing No. 15800-FY-147C
Calculation No. H-055
· Design Criteria
Title
Nuka Diversion Nuka· River Outlet
Structure -Plan
Nuka Diversion -Details
Nuka Diversion -Upper Brad.ley River
Outlet -Plan, Sections & Detail~
Nuka Diversion Conceptual Head Delivery
Curves
Hydraulic Design Criteria/Nuka Diversion
Also enclosed is an 8 1/2 x 11 inch sketch labelled Figure 1, entitled
"Nuka Diversion Concept". Figure 1 and the following text provide a
brief overview of how the Nuka Diversion will fu.nction:
Nuka Diversion Design Concept:
Glacial melt forms a pond called Nuka Pool at the terminus of the Nuka
Glacier. Nuka Pool discharges water both into the Upper Bradley River
and into the Nuka River. Water discharged into the Uppe~ Bradley River
flows to Bradley Lake. Water which is discharged into the Nuka River
flows into the Kenai Fjords National Park.
0 P.O. Box AM Juneau. Alaska 99811 (907) 465-3575
· t8l PO. Box 190869 701 East Tudor Road . Anchorage. Alaska 99519-0869 (907) 561-7877
2734/856
Mr. Boyd Evison
May 23, 1988 • Page 2
Page 12
The proposed structures are designed to divert the glacial meltwater
flowing through the Nuka Pool into the Upper Bradley River, while
meeting the Contract provisions requiring the first 5 cfs increment of
flow to be discharged into the Nuka River. The proposed structures are
shown on the attached Figure 1, entitled 11 Nuka Diversion Concept ...
Flow from the Nuka Pool to the Upper Bradley River will pass over a
long, un'fonn weir constructed by modifying the naturally occurring rock
weir at the pool outlet. At the Nuka River outlet of the pool, water
will be constrained to flow through a 12~inch steel pipe.in a gabion
dike. This pipe has been sized such that it will discharge 5 cfs when
the Nuka Pool level is at the elevation of the Bradley-side weir crest
and flow-is about to co11111ence to the Upper Bradley River. No flow is
allowed to enter the Upper Bradley River from the Nuka Pool until 5 cfs
-enters the Nuka River. A second, identical pipe will=also be provided.
This= second pipe will ensure flows if the first pipe becomes inoperative
and needs to be repaired. It may also be used to augment flows.
Case 1 in Figure 1 depicts the situation where less than 5 cfs of
meltwater flow is available. For such a case, the Nuka Pool level will
be below the Upper Bradley River Weir crest elevation and all flow will
pass to the Nuka .River, with none passing over the weir to the Upper
Bradley River. ·
Case 2 shows the pool elevation equal to the Upper Bradley River weir
crest elevation. This will occur when the meltwater flow is 5 cfs. In
this situation, all of the 5 cfs flow will go to the Nuka River.
C~s~ 3 shows further staging of the Nuka Pool where melt water passes
over the weir to the Upper Bradley River. Flow through-the pipe· to the
Nuka-River will be somewhat more than 5 cfs. This is because the head
on the 12 inch pipe, which was sufficient to drive 5 cfs throu~h when
the water in the Pool was at the Upper Bradl~y River weir crest level,
is now greater due to a slightly higher Pool level.
For details of the design, pleas~ refer to the enclosed drawings, design
criteria, and pp. 20-44 of_ the engineers•calculations.
As specified in the contract, provide any review cormnents you may have
within 60 days, but not later than July 25 1988. If we have not
2734/856
Mr. Boyd Evison
May 23, 1988
Page 3
received comments by that date we will assume that there are none.
Should you have any questions, feel free to contact me at (907)
561-7877.
Sincerely,
~0~_1! __
David R. Eberle
Project Manager
DRE/ds
Enc_losures as stated.
cc: Norm Bishop, Stone & Webster Engineering Corp. w/o enclosures
· -Harvey Elwin, Bechtel, w/o enclosures ---· -
-John Katz, Governor•s Office, D.C., w/o enclosures
2734/856
Page 13
Page 14
1. WATEf\ l..EVEL BELOW WE\R C:.t\E5T
Z. WATEf\ LE'JEL AT We\1\ CREST
3. WA\Et\ LEVEL ABOVE WE\A c.AES"T
NUKA DIVERSION CONCEPT
FIGURE · l _ _,
Attachment D
..
United States Department of the Interior
NATIONAL PARK SERVICE
IN REPLY REFER TO: ·
L54 {ARO-RNR).
ALASKA "REGIONAL OFFICE
2525 Gambell Street, Room 107
· . Anchorage, Alaska 99503. 2892
Mr. David R. Eberle
Project ·Manager
Alaska Power Authority
P.O. Box 190869_
701 East Tudor Road
Anchorage, AK 99519-0869
Dear Mr. Eberle:
2 1 JUL 1988
Page 15
As requested in your letter of May 23, 1988, the National Park
Service has reviewed design information and related documents on
the N'Uka RiverDiversion, a· component of the Bradley Lake .
Hydroelectric Project adjacent to Kenai Fjords National Park.
The design information was,included. in your letter and was
prepared by Stone and Webster Engineering Corporation.
. .
our Water Resources Division, based in Ft. Collins, Colorado, has
performed calculations that show that th~ interests of the_ United
states, as described in a-June, 1986 Agreement between the
Department of Interior and the Alaska Power Authority, will be·
· protected. This assumes, of course, that the diversion structure
will be bui~t in strict accordance with the specifications shown
in the documents forwarded to us .for review. ·
Thank·you for the opportunity to review this design.
Sincerely,
Richard J. Stenmark
· \:tin9 Regional Director
-
I ' .~ .. -
--~----
~~ --_---
-
-~
' .. . ..
---:--
'-· ,r ---·------::-----
SECTION 2.0
CONTROL SYSTEM
DESIGN CRITERIA
BRADLEY LAKE HYDROELECTRIC PROJECT
ALASKA POWER AUTHORITY
ANCHORAGE, ALASKA
CONTROL SYSTEM DESIGN CRITERIA
J.O. No. 15800
REVISION: 1
DATE: June 27, 1988
Stone & Webster Engineering Corporation
Anchorage, Alaska
CONTROL SYSTEM DESIGN CRITERIA
TABLE OF CONTENTS
Section Title
1.0 FOREWORD
1.1 Purpose
1.2 Control Systems
1.3 Control Logic
1.4 Site Conditions
2.0 CONTROL PANELS
2.1 Main Control Board
2.2 Protective Relay Panels
2.3 Station Auxiliary Equipment Control
2.4 Station Parameter Monitoring
2.5 Panel Mounted Equipment
3.0 SUPERVISORY CONTROL AND DATA ACQUISITION SYSTEM
3.1 Description
3.2 Hardware Required
3.3 System Functions
Page
1
1
1
2
2
3
3
4
4
4
6
8
8
9
10
1.0 FOREWORD
1.1 Purpose
This design criteria is prepared to define guidelines that will be
followed in the design and construction of the control systems for the
Bradley Lake Hydroelectric Project. It is intended to be used by all
engineering and construction firms, and groups as input to procurement
specifications, construction drawings, installation instructions, and
erection specifications.
1.2 Control Systems
The control and monitoring system will be design for _unattended plant
operation. Only maintenance personnel will be required.
The control systems will be designed for two 45 MW units. However, the
systems will be designed so as not to preclude the addition of a third
unit.
The following will be provided.
Control panels located in a main control room in the Powerhouse. These
panels will allow manual and automatic control of two units, station
auxiliaries, and the substation.
A Supervisory Control and Data Acquisition System (SCADA) with an
onsite computer system for monitoring and logging of station data and
events, control of power tunnel and diversion tunnel equipment, and
operation of Bradley Junction disconnects.
A Remote Terminations Unit (RTU) interfacing with an existing
supervisory control system at a remote dispatch location will be
provided by the dispatching utility. This will provide automatic unit
control, monitoring of critical station data and alarms, and control
5081R/CM -1-
of substation breakers at the dispatch location. The conununications
signal to the dispatch location will be continuously monitored and
alarmed at the powerhouse on loss of the signal.
The failure of the SCADA system will result in the loss of dispatch
access to station control and data monitoring. Safe plant operation
will not be dependent on this system. The plant will be operable and
capable of being maintained in a safe condition with only the local
control and monitoring equipment functional.
1.3 Control Logic
Auxiliary equipment will utilize hard wired relay logic or solid state
Programmable Controllers (PC). PC' s will only be used for control
where the control logic is complicated enough to· realize enhanced
reliability and a cost savings over the alternate hard wired relay
logic. Unit start logic will be implemented in a PC. Protective
shutdowns will be hardwired, independent of any PC.
1.4 Site Conditions
All equipment and systems shall be designed for use in a remote
. hydroelectric plant located on the Kenai Peninsula, about 105 air
miles south of Anchorage, and 27 miles northeast of Homer; Alaska.
All equipment and panels shall be designed to withstand a seismic
event in accordance with UBC Zone 4, without failure that would be
hazardous to personnel and other equipment.
5081R/CM -2-
2.0 CONTROL PANELS
2.1 Main Control Board
A duplex control panel will be located in the control room. The
panels will be free standing vertical sections. Display and control
devices wil~ be mounted according to system flow.
The front side of the panel will be considered the Main Control Board
(MCB). It will have monitoring devices for all critical station
parameters and control devices for control of each turbine-generator
unit and the substation. Sections will be provided for:
Unit 1 and 2 Generator Control
Unit 1 and 2 Governor Control
Substation Mimic and Control
Common Station Indication and Control
Indicators will be provided to monitor generator amps, volts, watts,
vars, watt hours and speed, and exciter volts and amps.
Control switches will be provided for breakers requiring remote
control, emergency closing of the spherical valves and intake gates,
and automatic opening and closing of the spherical valves~
All equipment that must be moni tared during start-up and shut-down,
and all equipment whose failure could result in the loss of power
generation will have its status displayed continuously by indicating
lamps generally located adjacent to the equipment control device.
A swing panel containing a synchroscope, incoming and outgoing volt
meters and synchronizing lights will be mounted on the right end of
the main control board.
5081R/CM -3-
Unit start sequencing lights will be located on each unit control
section to display the status of auxiliary equipment and prestart
permissives during the unit start sequence.
2.2 Protective Relay Panels
The rear of the duplex panel in the control room will have sections
for unit and substation protective relays, and station watt/var hour
metering.
2.3 Station Auxiliary Equipment Control
Auxiliary equipment (pumps, compressors, filters, etc.) will be
controlled from the appropriate MCC cubicle. The control location
will have indicating lights to show the current operational status of
the equipment.
2.4 Station Parameter Monitoring
Station parameters will be monitored in accordance with the following
criteria:
Final Trip Parameter:
A final trip parameter is a parameter which, when it deviates from
specific limits, will directly result in the shutdown of the unit.
Final trip parameters will be alarmed as a first-out indication; i.e.,
the first parameter deviation which occurs that initiates the shutdown
will be· flashing accompanied by an audible horn and logged in the
SCADA System .
. SQ81R/CM -4-
\
' Short Response Parameter:
A short response parameter is a parameter which requires immediate
operator action when the parameter deviates from specific limits. The
parameter deviation will be alarmed in the annunciator by a flashing
light and audible horn, and logged in the SCADA System.
Long Response Parameter:
A long response parameter is a parameter which does not require
immediate operator action when the parameter deviates from specific
limits. Alarms for such parameters may be grouped and identified as
system or equipment trouble. Long response parameters will be
annunciated at the MCB and logged in the SCADA System.
Advisory Parameter:
An advisory parameter is a parameter which, if ignored by the
operator, might result in an unacceptable deviation of a short or long
response parameter. Such parameters will be alarmed in the SCADA
System.
2.5 Panel Mounted Equipment
Devices mounted on the control panels will include the following:
Annunciators:
Unit and substation annunciators, and a common station annunciator
will be located on the Main Control Board. The annunciator windows
within each system area will be used to identify, in descending order,
final trip parameters as well as short response and long response
parameter 4eviations. Annunciator windows assigned to identify trouble
associated with locally operated auxiliary systems will be grouped in
one area of the annunciator display. Spare annunciators will be
provided for future use.
5081R/CM -5-
I
The annunciator will be controlled by a PC. It will be provided with
an audible alarm warning device, operational test features, and
acknowledge, silence, and reset push-buttons. The PC will perform ISA
sequence "M" annuciator logic, and provide auxiliary_ -outputs to the
SCADA System.
All inputs to the annunciator will be repeated as alarms in the SCADA
System. This will be done by utilizing output contacts from the
annunciator PC. Where an annunciator window has several inputs, each
input will be retransmitted as a separate input to the SCADA System.
Display Devices:
Hard wired, edgewise, vertical indicators for continuous monitoring .of -
process variables.
270° circular scale indicators for monitoring electrical system
parameters (watts, vars, voltage, current, etc.).
Status indicating lights for monitoring discrete states of equipment.
Control Devices:
Multi-contact circuit breaker type control switches with spring-return
pistol grip handle and target.
Heavy duty selector switches and push-buttons.
Control Relays:
Compact solid state and electro-mechanical relays and timers.
Protective Relays:
5081R/CM -6-
See Electrical Design Criteria protective relay section for relay
criteria.
3.0 SUPERVISORY CONTROL AND DATA ACQUISITION SYSTEM.
3. 1 Description
The Supervisory Control and Data Acquisi t'ion System (SCADA) will be
designed for the following functions:
1. Communicate with Remote Termination Units (RTU) at the mouth of
Bradley River, the
tunnel gatehouse.
outputs for control
release valves.
diversion tunnel· gatehouse~
'' These RTUs w:ould provide
of. the power tunnel ·gates
and the power
data· input, and
·and fish · Wa.ter
2. Monitor station parameters, store the data obtained, and display
it in useable form in t~e powerhouse control room and at the APA
office in Anchorage. Provide alarms on significant deviations of
station parameters.
3. Communicate wit~ the permanent camp to alert onsi te personnel of
alarm conditions at the powerhouse.
4. Connnunicate and display data at a terminal 1n the Homer Electric
Association (HEA) Operations Center.
An RTU will be provided by the Chugach Electric Association (CEA) for
. '
communi cat ion with the CEA dispatch center. This RTU wi 11 provide CEA
with unit start/stop, unit loading, substation breaker .control, and
minimal data· and alarms. These control functions will be· enabled by
manual selector switches located on the main control board.
5081R/CM -7-
3.2 Hardware Required
Powerhouse
Two color CRTs and keyboard-Operator's station with cursor control.
Log printer -For printing logs and reports. Also used for plotting
trends, and printing graphic displays and programming information.
Alarm printer -Dedicated for printing alarms in real time.
Mass storage -Disc or tape system for storage of historical data.
Floppy disc for short term program and data storage.
Computer -Dual microprocessors or minicomputers for system control ·
and data manipulation.
RTU For data inputs from common station equipment and the
turbine-generators.
Modems -To communicate with the terminal/computer in the APA offices,
permanent camp, HEA Operations Center and RTUs remotely located.
Offsite
Homer Electric Association (HEA) Operations Center
Keyboard, and printer.
Color CRT,
APA offices
microcomputer.
Color CRT and keyboard terminal or IBM PC type
Permanent Camp -Color CRT and keyboard terminal or IBM PC type
microcomputer.
5081R/CM -8-
3.3 System Functions
Powerhouse -Open/close control of the fish release valves and close
control of the power tunnel gates.
Each control action will be accompanied by a corresponding status
change on the CRT display. If a valve is opened, it will reflect the
open state on all displays containing that valve. Data will be
displayed in text or graphic displays. Analog points will be capable
of being trended.
The system will be supplied with standard software for control, data
display, and RTU polling. Programming of graphic displays, database,
and control functions will be done by SWEC.
APA Offices -Via the terminal, all station data will be accessible.
This data will not be real time but will reflect the current status or
value when accessed. This terminal will be equipped with graphics
software for similar displays and trending as in the powerhouse
terminal.
Permanent camp -Located in the office/residence at the permanent camp
will be a terminal similar to that at the APA offices. When the plant
computer detects an alarm condition, it will alert the camp personnel
via telephone. The computer will have auto dial equipment to call
'each location in the camp in a predetermined sequence until
answered. When answered, it will sound an alarm tone. The camp
personnel may then access the · alarms at the CRT· in the office and
determine if it needs immediate attention. The alarm must be
acknowledged or the calling sequence will repeat.
HEA Operations Center -All station data will be available. Graphics,
trending, and logging software will be provided.
5081R/CM -9-
SECTION 3.0
MECHANICAL
DESIGN CRITERIA
4234R/LS
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J.O. NO. 15800
MECHANICAL DESIGN CRITERIA
Revision No. 2
Date: June 6, 1988
STONE &"WEBSTER ENGINEERING CORPORATION
Anchorage, Alaska
MECHANICAL DESIGN CRITERIA
MECHANICAL DESIGN CRITERIA
1.0 General
2.0 Service Water System
3.0 Compressed Air System
4.0 Depression Air System
5.0 Oil System
6.0 Fire Protection System
7.0 Heating and Ventilation System
8.0 Domestic Water and Drainage System
9.0 Diesel Generator Fuel System
10.0 Bridge Crane
11.0 Remote Structures
it Asterisk in right hand margin indi_cates a change to previous issue of
this document.
4234R/LS -MECHANICAL DESIGN CRITERIA
Page 1
1.0 GENERAL
1.1 DESCRIPTION
The Bradley Lake .Project is being designed for the Alaska Power
Authority. The project will ·be located ·approximately 27 miles
northeast of Homer, Alaska and approximately 105 miles south of
Anchorage, Alaska at the southern end of the· Kenai Peninsula. The
project consists of a dam, diversion tunnel, .power tunnel,
powerhouse, substation, transmission line, diversion works, and
various support facilities. The . mechanical design criteria applies
primarily to the powerhouse.
1.2· FUNCTIONS·
The powerhouse will develop a nominal ·90 MW of electrical power with
two Pelton turbine-generator units and deliver power to the
substation for transmission. Provisions will be made for future
addition of.a third unit.
1.3 DESIGN CONSIDERATIONS
Special design consideration include the following:
1. Reliability consistent with remote site operations. Standby
equipment for critical operations, on-site replacement for wearing
parts, and low speed operation for extended life. *
2. Easily understood and maintained systems for operation and
maintenance by a small staff.
3. Maintain plant safety. during all operation.
4. Adhere to environmental requirements.
5. Remote operation with a minimum of on-site intervention.
4234R/LS MECHANICAL DESIGN CRITERIA
Page 2
6. Addition of a third unit in the future-.
1 • 4 CRITERIA AND STANDARDS
The following specifications, standards, and codes will be used in
mechanical design. Unless otherwise specified, the latest edition
applies.
ANSI B31.1
·ASHRAE 90
ASHRAE
HANDBOOK
ASHRAE
HANDBOOK
American National Standards Institute, Power Piping
American Society of Heating, Refrig~ration and Air
Conditioning Engineers.
building design.
Energy conservation in new
American Society of Heating, Refrigeration and Air
Conditioning Engineers. Fundamentals Volume.
American Society of Heating, Refrigeration and Air
Conditioning Engineers. Systems Volume.
ASME American Society of Mechanical Engin~ers. Pressure
SECTION VIII Vessel Design.
ASME LOS-S
-AWWA
CMAA 70
FERC
4234R/LS.
American Society of Mechanical Engineers.
Oil Systems.
American Water Works Association.
Crane Manufacturers Association of America.
Overhead Crane Design.
Lubricating
Electric
Application for License for Majo_r · Unconstructed Project, ·
Bradley Lake Hydroelectric Project, Volume 1 through 10,
by Stone & Webster Engineering Corporation, for Alaska
Power Authority, 1984.
MECHANICAL DESIGN CRITERIA
NEC
NFPA
OSHA-AK
OSHA-US
SMACNA
UBC
UMC
UPC
National Electrical Code.
National Fire Protection Association.
Codes Volumes 1 through 16.
Page 3
National Fire
General Safety Code, Vol I, II, and III, Occupational
Safety and Health Standards, Alaska Department of Labor,
Division of O~cupational Safety and Health.
U.S. Department of Labor Occupational Safety and Health
Administration, OSHA 2206 General Industry Standards (29
CFR 1910, and OSHA 2207 General Industry (29 CFR
1926/1910).
Sheet· Metal and Air Conditioning Contractors National
Association.
Uniform Building Code.
Uniform Mechanical Code.
Uniform Plumbing Code.
2.0 SERVICE WATER SYSTEM
2.1 DESCRIPTION
A closed loop service water system will be provided to remove waste
heat from plant equipment and reject this heat to a heat exchanger.
The cooling water side of the heat exchanger wi 11 be supplied by
vertical turbine pumps pumping turbine discharge water through the
heat exchanger to the tailrace. The turbine discharge water will be
collected in collection troughs and stored in the clean water sump.
A penstock tap will maintain water level in the clean water sump if
collection troughs do not operate properly and provide water for the
air compressor after coolers and the control room cooling system.
4234R/LS .. ·· MECHANICAL DESIGN CRITERIA
Page 4
2. 2 OPERATION
Service water will be available to the following equipment:
1. Generators
2. Turbines
3. Air Compressor After Coolers
4. Air Handling Unit Cooling Coil
Two identical service water pumps and component cooling water pumps
will be provided. One pump will be a backup to the operating pump.
2.3 DESIGN CONSIDERATIONS
1. Operation required with tailwater depression system actuated.
2. A penstock backup will be provided to maintain clean water sump
water level.
3. Water treatment provisions will be provided.
4. Service water system will be designed to prevent brackish water
contamination in.the turbine sump.
5. The service water system will be sized for Units 1 and 2 only. A
new system will be provided if a future Unit is added.
6. Service water lines will be insulated where required. to prevent
condensation.
2.4 DESIGN CRITERIA
4234R/LS. MECHANICAL DESIGN CRITERIA
Page 5
2. 4.1 APPLICABLE CODES
The service water system will be designed in accordance with the
following National Codes:
EQUIPMENT
Piping & Pipe
Supports
2.4.2 SYSTEM DESIGN CRITERIA
Penstock Head
Pipeline Velocity
CODE/STANDARD
ANSI B31.1
Inlet Temperature to Coolers
3.0 COMPRESSED AIR SYSTEM
3.1 DESCRIPTION
1175 feet normal
2350 feet maximum
5-10 fps
45 o F maximum
Compressed air will be provided for plant service air, and
instrument air.
3.2 OPERATION
Two 95 scfm, 125 psig, air cooled compressors will be
provided for the normal supply of plant service air and
instrument air to Units 1 and 2. Service and .instrument
air will discharge directly to a receiver tank. Service
air will be filtered and distributed to air stations
strategically located throughout the powerhouse.
Instrument air will be filtered · and dried prior to
discharge to an instrument air receiver tank and
distribution.
4234R/LS MECHANICAL DESIGN CRITERIA
3.3 DESIGN CONSIDERATIONS
The following engineering and design aspects shall be
taken into consideration:
1. Inlet silencers and vibration mounts will be provided
to attentuate noise and vibration.
2. Use automatic start ·and stop control. Receivers will
be sized to provide adequate stop and run times.
3. Receivers will be sized to provide load factor reserve.
4. The receiver tank and separator will have automatic
traps for moisture removal.
5. The air dryer will regenerate automatically.
3.4 DESIGN CRITERIA
3.4.1 APPLICABLE CODES
The compressed air system will be designed in accordance
with the following National Codes:
EQUIPMENT CODE/STANDARD
Piping ANSI B31.1
Receivers/Coolers ASME Section VIII
-
Page 6
4234R/LS--MECHANICAL DESIGN CRITERIA
3.4.2 SYSTEM DESIGN CRITERIA
Service Air System:
Number Stations
Air Requirement per Station
Use Factor
Load Factor
System Capacity
System Pressure
Instrtiment Air System:
Air Requirements
Load Factor
System Capacity
Dew Point
4.0 DEPRESSION AIR SYSTEM
4.1 DESCRIPTION
20
50 scfm
.05
1.25
90 scfm
125 psig
30 scfm Max
2 1/2 scfm Normal
2.0
.5 scfm
-40 Degrees F
Page 7
A depression air system will suppress the water level in the turbine
chamber during full load operations at high tide. This allows the
Pel ton turbine to operate without its efficiency being impaired by
the "foam" inside the turbine chambers.
4.2-OPERATION
A 3200 scfm, 2. 6 psig fan will be provided for tail water depression
in each chamber. A fan will start automatically whenever the tide
level is high enough to affect turbine efficiency. Water level will
be controlled by a modulating bypass valve.
4234R/f.S. MECHANICAL DESIGN CRITERIA
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Page 8
4.3 DESIGN CONSIDERATIONS
The following engineering and design aspects will be considered:
1. Inlet and exhaust silencers will be provided to reduce noise.
2. The units will· be packaged and skid mounted to the greatest extent
possible.
3. The depression air piping will be large enough so that sufficient
aeration will be provided when the depression air fans are not
operating.
4. Intake shall be outside air.
4.4 DESIGN CRITERIA
4.4.1 APPLICABLE CODES
Equipment
Piping
Fans
4.4.2 SYSTEM DESIGN CRITERIA
Number of Fans
Fan Capacity (each)
Design Pressure
Noise Level
·5.0 OIL SYSTEM
4234R/LS.
Code/Standard
ANSI B31.1
AMCA 210
2
3200 scfm
3.4 psig
90 DB @ 3 Ft Max
MECHANICAL DESIGN CRITERIA
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Page 9
5.1 DESCRIPTION
The oil system includes portable coalescing filter units to purify
the following plant oils:
1. Turbine lubricating oil
2. Generator lubricating oil
3. Governor oil
4. Spherical valve control oil
5. Transformer oil
5.2 OPERATION
A pump ·and filter unit will be provided to remove such contaminants
as water, pipe scale, metallic wear· particles and oil degradation
products from the turbine-generator lubrication and control oil and
the spherical valve control oil as appropriate. A second unit will
be provided to remove similar contaminants from the transformer oil.
5.3 DESIGN CONSIDERATIONS
The following engineering and design aspects shall be taken into
consideration:
1. Piping connections will be required for hook-up of purification
equipment on the control units, turbine-generator and
transformer. Drain connections shall be provided at a low point
to facilitate removal of solid contaminants and water.
2. Delivered oil will be assumed to be contaminated and will be
treated prior to charging either the turbine-generator or
transformer.
3. Storage facilities will be sufficient to store at least one full
charge of turbine oil and one charge of dirty turbine oil for the
largest turbine oil reservoir.
4234R/LS MECHANICAL DESIGN CRITERIA
Page 10
. 4. The inside surfaces of oil piping will be coated with an oil
soluble rust preventative prior to erection.
5. Sarnp~e connections will be provided for periodic oil quality
analysis.
6. Oil will be supplied in standard drums.
5.4 DESIGN CRITERIA
5.4.1 APPLICABLE CODES
The system will be designed in accordance with the following National
Codes and Standards:
Piping
Purifier/Filter
Oil Purification
Oi 1 Flushing
Design
5.4.2 SYSTEM DESIGN CRITERIA
ANSI 831.1
ASME Section VIII
ASME Standard LOS-5PI
ASME Standard LOS-5Cl
ASME Standard LOS-5Dl
Turbine-Generator and Transformer Oil Requirements:
Free Water
Maximum Particle Size
Governor Capacity
6. 0 FIR.E PROTECTION SYSTEM
4234R/:GS~
None
10 Microns
750 Gallons
MECHANICAL DESIGN CRITERIA
Page 11
6.1 DESCRIPTION
Fire protection systems will be _provided at the powerhouse and
permanent camp. The extinguishing agents used shall be water
supplied from the turbine . penstock or Halon 1301. Portable
extinguishers shall be either Halon 1301 or dry chemical. A fire
pump will be provided as backup.
6.2 OPERATION
6.2.1 SPRINKLER/DELUGE SYSTEMS *
Fire protection water shall be supplied from the penstock tap. A
pressure reducing station shall be installed to reduce the system
supply pressure to approximately 100 psi_g. The water shall pass
through a strainer before supplying the following areas:
1. Emergency Gener·ator Room Sprinkler System
2. Battery Room, Rest Room, and Lift Station Sprinkler System
3. Deluge Systems for Transformers (3)
4. Fire Line to Permanent Camp
5. Machine Shop Sprinkler System
6. Hose Stations at Each Level
7. Turbine and Spherical Valve Hydraulic Units
a. Office, Electric Shop, Lunch Room, and Locker Room Area Sprinkler
System
9. Mezzanine Sprinkler System
All inside systems shall be wet pressurized systems with fusible link
sprinkler heads. Outside deluge systems shall be dry unpressurized
*
*
*
systems with open fixed directional spray heads at the transformers. *
4234R/LS MECHANICAL DESIGN CRITERIA
Page 12
6.2.2 HALON 1301 SYSTEMS
Automatic total flooding type Halon 1301 fire suppression systems
will be provided for each generator, oil storage room, and the
control room. An initial and reserve supply of Halon 1301 will be
provided with the reserve supply actuated manually.
Halon flooding will be provided at the following points:
1. Generator til inside casing and in barrel
2. Generator 112 inside casing and in barrel
3. Control Room including computer floor
4. Oil storage room
6.2.3 PORTABLE EXTINGUISHERS
Portable fire extinguishers will be provided throughout the
powerhouse. Extinguishers containing Halon 1301 shall be provided at
each generator, the SF6 room and in the control room. All other
extinguishers shall be the dry chemical rated for type A, B, and C
fires.
6.3 DESIGN CONSIDERATIONS
the following engineering and design aspects will be· taken into
consideration:
1. Water p·iping will be installed and protected as necessary to
eliminate potential freezing.
2. The proper pipe classes will be selected to handle. the pressures
expected both upstream and downstream ·o~ ·the approved pressure·
reducing station. Downstream piping will be protected by a
pressure relief valve.
4234R/L~-MECHANICAL DESIGN CRITERIA
Page 13
3. Piping materials and ·design velocities will be selected to-
minimize erosion from possible high concentrations of suspended
minerals in the penstock water.
4. The fire protection systems will be sized for Units Number 1 and 2
only. A .full-sized valved tee shall be provided in the fire main
~or extension to future Unit Number 3.
5. A six-inch fire line will be extended to the permanent camp. Pipe
will be buried below frost line to prevent system freezing.
6. Distribution systems will be designed to operated with glacial
silt in the water system.
7. Backup systems will consist of an electric motor driven fire pump
and jockey pump. Water reservoir will be the clean water sump.
8. The generator protection system will be sized to protect the
turbine cap area.
9. The strainer will be a dual filter type.
10. Water extinguishing. systems shall be hydraulically designed
per NFPA requirements.
11. Smoke & Heat Detectors. Ionization, rate of rise, and fixed
temperature types shall be used and cross zoned in critical
areas.
12. Fire and smoke dampers shall maintain minimum
concentration per NFPA in protected areas.
gas
6.4 ·DESIGN CRITERIA.
4234R/LS-MECHANICAL DESIGN CRITERIA
Page 14
6.4.1 APPLICABLE CODES
The fire protection systems shall be designed in accordance with the
following National Codes:
NFPA -National Fire Protection Association Standards. All equipment
and devices shall be UL listed and/or FM approved.
6.4.2 SYSTEM DESIGN CRITERIA
Penstock Pressure
Pipeline Velocity
Water Temperature
Outdoor Design T~mperature
Sump Capacity
Halon 1301 Flooding
Sprinkler Design
Hose Station
7.0 HEATING AND VENTILATION SYSTEM
7.1 DESCRIPTION
1650 Ft. Hd. Design
· 10 FPS Maximum
40 Degrees F Minimum
-10 Degrees F Normal
-38 Degrees Extreme
100,000 Gallon Minimum
7% Minimum Halon Concentration
0.3 gpm/sq. ft.
15 psi minimum
SO gpm minimum
65 psi minimum
Heating and ventilation systems shall be provided in the powerhouse
to maintain design temperatures and· ventilation requirements.
Heating will be provided by generator heat recovery, electric
propeller type unit heaters, electric resistance type coils in air
handling equipment, and by exchanging areas. Space cooling shall be
accomplished· by. ventilating with outdoor air except in the control
room area where cooling coils will be provided in the ventilation
duct.
4234R/LS. · MECHANICAL DESIGN CRITERIA
Page 15
7.2 OPERATIONS
7.2.1 HEATING
The primary heating system shall be by heat recovery from the
generator cooling systems. Adjustable louvers in the side of the
generator case will allow warm air to escape int9 the lower level
area where circulating fans will distribute the air. Air will flow
to the operating level at stairwells and gratings. A portion of the
air will return to the generator cooling system through louvers in
the generator cap, the remainder will rise to the ceiling area where
ventilation fans will circulate the air back to operating floor level
and lower level. Electric propeller type unit heaters or electric
duct heaters with individual thermostats will be provided at the.
perimeter of each level and at the service bay door. These heaters
will provide additional heat when required and total heat during
statiqn shut down.
The control room will be heated by an air handling unit with electric
heating coil.
7.2.2 VENTILATION
The diesel generator room, battery room, oil storage room, locker
room, and toilet rooms will have exhaust fans to prevent accumulation
of odorous and combustible gases.
Mixing box sections and filters will be provided at the circulation
fans, air handling unit, and battery room to blend outdoor and
recirculation air. Gravity relief dampers will maintain positive
pressure in the powerhouse.
4234R/L8_ _ MECHANICAL DESIGN CRITERIA
Page 16
7.2.3 COOLING
Mixing box sections at the circulation fans, battery room, and air
handling unit will vary outside air quantity from 0 to 100% for
cooling interior spaces. Two exhaust fans above the excitation
equipment will operate when 100% outside air is not adequate for
cooling. Gravity dampers above the crane rails will exhaust warm
interior air when cooling requirements pressurize the building.
Intake louvers will open to provide additional outside air makeup
when the exhaust fans are operated.
The air handling unit will be provided with cooling coils. When
required for control room cooling, service water will be supplied to
the coils.
7.3 DESIGN CONSIDERATION
1. Provide an Electrostatic filter at control room air handling unit.
2. Provide positive pressure in the control room and office. Provide
negative pressure in the oil storage room, generator room, battery
room, and toilet rooms.
3. Provide 15% minimum outside air for ventilation.
4. There will be no roof penetrations. Wall penetrations shall have
weather hoods.
5. Electric unit heaters will be sized to heat the station when
generator recovery system is not operating.
6. All ductwork will be low pressure construction.
7. High humidity areas will be considered in ventilation requirements
and corrosion protection.
4234R/LS MECHANICAL DESIGN CRITERIA
Page 17
8. Fire dampers will be provided at all fire rated wall penetrations.
9. Outside air supply ducts will be insulated to minimize
condensation.
7.4 DESIGN CRITERIA
7.4.1 APPLICABLE CODES AND STANDARDS
The heating and ventilating systems shall be designed in accordance
·with the following:
UBC
UMC
NFPA 70
NFPA 90A -
SMACNA
ASHRAE 90 -
ASHRAE
Uniform Building Code
Uniform Mechanical Code
National Fire Protection
Electrical Code
Association National
National Fire Protection Association Standard for the
Installation of Air Conditioning and Ventilating
Systems.
Sheet Metal and Air Conditioning Contractors National
Association Standards for Duct Construction.
Energy Conservation in New Building Design.
Anierican Society of Heating, Refrigeration, and Air-
Conditioning Engineers Handbooks.
MECHANICAL DESIGN CRITERIA
7.4.2 SYSTEM DESIGN CRITERIA
Outdoor Design Temperature:
Indoor Design Temperature:
Wind Speed
Heating Degree Days
Wall Sections
Roof
Windows
Infiltration
Ventilation
Odor/Vapor Removal
Safety Factor
Page 18
Sununer 60° F Normal
68° F Design
Winter -10° F Design
-38° F Extreme
Control Room 75° F Heating
80° F Cooling
Station 65° F Cooling
90° F Cooling
Battery Room 65° F Heating
80° F Cooling
15° MPH Design
10,864 Design
R~l9 Design Upper Level Outside Walls
R-11 Insulation in Inside Walls
R-30 Design
R-2 Design
1 Air Change/Hour
15% Minimum
Outside Air for Occupied Area
6 Air Changes/Hour Minimum
1.20 for heat loss calculations
8.0 DOMESTIC WATER AND DRAINAGE SYSTEMS
8.1 DESCRIPTION
A domestic water supply system will. be provided at the powerhouse.
The water source wil_l be a collection crib in powerhouse creek with
·raw water pumped to ~ater treatment, storage, and a hydro_pneumatic
system at the shop/warehouse building. A second storage tank and
hydropneumatic system is provided at the powerhouse.
4234R/LS MECHANICAL DESIGN CRITERIA
Page 19
Separate drainage systems shall be provided to remove and dispose
of sanitary waste; and, waste water from equipment, floor and
miscellaneous drains.
8.2 OPERATION
8.2.1 DOMESTIC WATER
Domestic water shall be supplied to all plumbing fixtures. The
supply system shall include a water heater and distribution piping
system with valves and accessories.
8.2.2 SANITARY WASTE
The sanitary drainage system shall consist of plumbing fixtures
'
with drainage piping discharging to a lift station then into a
pressure main for disposal at a leach field near the powerhouse.
8.2.3 DIRTY WATER WASTE
Plant floor drains, equipment drains and drains from oil
containment areas will drain to a dirty water sump. They will then
be pumped through an oil interceptor before discharge to the
· tailrace. Oil trapped by the separator will drain to a· dirty oil
tank for transfer to drums and off-site disposal. Floor drainage
from the battery room will pass through a limestone neutralizer
before discharge to the tailrace.
8.2.4 HOSE STATIONS
Domestic water will be provided to hose stations throughout the
p!"ant.
4234R/Ls-MECHANICAL DESIGN CRITERIA
Page 20
8.3 DESIGN CONSIDERATIONS
The following engineering and design aspects shall be taken into
consideration:
1. All underground piping will be installed to minimize the
potential of freezing.
2. The septic tank and leach field piping will be installed to
allow access for tank maintenance and·rodding out of piping.
3. The-oil separator will be installed to allow access for
maintenance and gravity discharge to waste oil tank.
4. The 1 imestone neutralizer will be ·installed to allow visual
inspection, cleaning, and future addition of limestone.
Piping on the inlet side of the neutralizer shall be acid
resisting.
5. Design sanitary pressure main for ease of cleaning and
rodding pipe.
6. Provide systems to dewater all sumps.
7. Provide flow restrictors on showers (3 GPM each) and water
saving type water closets.
8. Provide wall mounted fixtures for ease of housekeeping.
9. Provide emergency eye wash and shower at battery room per
OSHA requirements.
10. Size dirty water sump for 6000 gal. transformer oil spill.
4234R/LS:-MECHANICAL DESIGN CRITERIA
8.4 DESIGN CRITERIA
8.4.1 APPLICABLE CODES AND STANDARDS
UPC Uniform Plumbing Code
AWWA American Water Works'Association
OSHA Occupational & Safety Hazards Administration
8.4.2 SYSTEM DESIGN CRITERIA
Pipeline Velocity
Water Temperature
Outdoor Design Temperature
Occupancy
Design Capacity
. Flow Requirement
9.0 EMERGENCY GENERATOR SUPPORT SYSTEMS
9.1 DESCRIPTION
10 fps Maximum
40° F Minimum
-10° F Normal
-38° F Extreme
2 Normal
50 gpm/Person
35 gpm instantaneous
domestic water flow
The fuel system shall consist of a fuel storage tank,
fuel supply piping and day tank, and a transfer pump.
The engine cooling system shall consist of a radiator,
ductwork. with recirculation air dampers, and motorized
dampers for fresh air supply.
9.2 OPERATION
The fuel storage tank will be refilled with a tank truck
barged to the station site from Homer. From the storage
tank fuel wi 11 be pumped to a day tank from which the
engine mounted fuel pump will circulate fuel through the
injectors.
Page 21
4234R/LS-MECHANICAL DESIGN CRITERIA
The engine cooling system shall consist of an· engine
driven fan and water pump circulating air and engine
coolant through an engine mounted radiator. Radiator
ducts to the outside will have thermostatically
controlled modulating dampers· to recirculate air back
into the emergency generator room to maintain room
temperature. Gravity dampers will provide make up air.
9.3 DESIGN CONSIDERATIONS
The following engineering and design aspects shall be
taken into consideration:
1. Provide truck access to storage. tank. Provide
10,000 gallons minimum storage at powerhouse to
utilize a 10,000 gallon truck.
9.4 DESIGN CRITERIA
Storage Tank
Day Tank
Room Temperature
10.0 BRIDGE CRANE
14 days
operation.
full
10,000
load
gallon
minimum size at powerhouse.
12 hours full load operation
minimum.
maximum with engine
operating.
65° with engine not running.
Page 22
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4234R/LS'. MECHANICAL DESIGN CRITERIA
10.1 DESCRIPTION
The bridge crane will be an overhead type with main
hook, auxiliary hook, pendant control station, and
runway conductors.
10.2 OPERATION
Crane shall be used for assembly and disassembly of
turbine and generator; and, for transporting materials
between operating floor and lower level.
10.3 DESIGN CONSIDERATIONS
1. Size main hook to lift heaviest turbine-generator
part.
2. Provide access for maintenance.
3. Provide clearance openings at spherical valves
and turbine pumps.
4. Provide for slow speed operation on both hooks.
5. Provide for rail extension when Unit 3 is
constructed.
6. Provide variable speed control on crane and
bridge.
10.4 DESIGN CRITERIA
10.4.1 Applicable Codes
The system will be designed in accordance with CMAA No.
70 Specification for electric overhead traveling cranes.
Page 23
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4234R/LS. MECHANICAL DESIGN CRITERIA
10.4.2 Design Criteria
Main Hoist
Auxiliary Hoist
Seismic
Auxiliary Hook Approach
11.0 REMOTE STRUCTURES
11.1 DESCRIPTION
160 Ton Capacity
25-Ton Capacity
OBE Load Case
5-Feet Minimum
Page 24
Remote structures that require mechanical equipment are the power
tunnel gate shaft, t~e power tunnel gatehouse, the diversion tunnel
gate shaft, the diversion tunnel gatehouse, the diversion tunnel,
the diversion tunnel outlet portal, and the spillway gallery.
Required sys~ems include heating, ventilation, drainage, fire
protection, and standby power fuel systems. These structures are
occupied for inspection and maintenance only and are normally
unmanned.
11.2.1 HEATING
Heating for freeze protection is required at the power tunnel gate
shaft~ power tunnel gate house, diversion tunnel gate shaft,
diversion tunnel gatehouse, and diversion tunnel outlet portal. The
heating system will consist of unit heaters each controlled by a
thermostat. Thermostat settings will be for freeze protection only,
not comfort heating.
The diversion tunnel and spillway gallery do not require heating
systems. Because of the extensive surface cover, temperatures will
remain above freezing throughout the year.
4234R/LS-MECHANICAL DESIGN CRITERIA
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Page 25
11.2.2 Ventilation
Ventilation systems are required in. the power tunnel gate shaft,
diversion tunnel gate shaft, diversion tunnel, and spillway
gallery. The spillway gallery is ventilated with an exhaust fan
which is manually turned on when personnel enter the gallery and
turned off when they leave. The remaining structures are ventilated
with . supply fans manually turned on when personnel enter the shaft
or tunnel and turned off when they leave. The supply fans are
provided with duct heaters to temper the outside air when
temperatures are below freezing.
A carbon monoxide detector is located in ·the bottom of each gate
shaft. A carbon. monoxide indication will turn on the ventilation
fan and sound an alarm. The alarm/fan actuation system is
controlled by a timer and air quality will be reanalyzed when the
system times out.
The gate houses and outlet portal are ventilated by infiltration
when mechanical ventilation is turned off.
Standby generator ventilation consists of duct between the radiator
and the outside with face and bypass dampers; and, a motorized inlet
air damper.
The thermostatically controlled face and bypass damper will bypass
heated. air into the gate house until a preset building temperature
is reached. It then modulates to maintain · the preset temperature.
The motorized damper opens when either the sta!}.dby generator or the
vent.ilation fan is on. It. equalizes building pressure by allowing
. .
ventilation air to enter the building for generator operation or
exhaust the building for fan operation.
4234R/LS·· · MECHANICAL DESIGN CRITERIA
Page 26
11.2.3 Drainage
Drainage is not provided in the gate houses. The equipment area is
diked to retain fuel oil or hydraulic fluid leaks. Moisture outside
the diked area will be mopped.
Moisture from the gate shaft wall, from condensation, and from
leakage will be collected in a sump at the bottom of the shaft. At
the power tunnel, a sump pump will discharge through an oil
separator into the penstock air vent line. At the diversion tunnel,
discharge shall be by gravity through an oil separator at the outlet
portal to the Bradley River. Tunnel drainage shall be along the
tunnel floor to sumps at the outlet portal. Sump pumps with level
control shall discharge into the Bradley River.
Monitored drainage from the spillway gallery is included in the
Geotechnical Design Criteria and not included in this document.
11.2.4 Fire Protection
Portable extinguishers, dry chemical type rated for type A,B, and C
fires shall be provided at each gate house, each gate shaft, and at
the outlet portal.
11.2.5 Fuel Systems
A fuel system shall be provided for the standby generator at the
power tunnel gate house. The system shall consist of an
above-ground storage tank and a day tank inside the gate house. The
storage tank shall have a self-contained dike, covered to prevent
entry of rain or snow.
A day tank will be provided for the diesel driven hydraulic pump at
the diversion shaft gatehouse. This tank will be manually filled
from portable fuel containers.
. 4234R/tS MECHANICAL DESIGN CRITERIA
Page 27
11.3 DESIGN CONSIDERATIONS
1 •. All heating elements to be electric.
480/240 power is available.
Only single phase
2. No roof penetrations. Wall penetrations shall have weather
hoods and bird screen.
3. Ventilate underground structures at 4 air changes per hour
minimum when occupied.
4. Provide carbon monoxide detectors when diesel fumes may
collect underground.
5. Provide oil separator prior to drainage system discharge.
6. Provide oil containment for fuel oil tanks.
7. Provide for 277 Volt supply to heating elements connected to
emergency generator.
8. Provide motorized dampers where required to prevent natural
drafts in gallerys and shafts.
11.4 DESIGN CRITERIA
11.4.1 Applicable Codes
systems shall be designed in accordance with the following codes:
ASHRAE
NF·PA-10
4234R/LS
American Society of .Heating, Refrigeration, and Air
Conditioning Engineers; Fundamentals Handbook.
National Fire Protection Association.; Portable Fire
Extinguishers.
MECHANICAL DESIGN CRITERIA
NFPA-30
Page 28
National Fire Protection Association; Flanunable and
Combustible Liquids Code.
NFPA-70 National Fire Protection Association; National
Electrical Code.
SMACNA Sheet . ·Metal and Air Conditioning Contractor.s
National Association.
11.4.2 System Design Criteria
Outdoor Design-Temperature
Indoor Design Temperature
Average Wind Speed
·Building Insulation
Infiltration
Ventilation
H&V Safety Factor
Hydraulic Fluid Reservoir
Oil Separator
Fuel Oil Tank
Day Tank
4234R/LS :-
68° F summer
-10° F winter
35° F underground
45° F minimum
90° f maximum
15 MPH
R10 walls
R10 roof
1 air change/hr
4 air change/hr
1.2
500 gal max:
50 gpm
300 gal
36 hr @ full load
100 gal
12 hr @ full load
*
MECHANICAL DESIGN CRITERIA
SECTION 4.0
STRUCTURAL
DESIGN CRITERIA
4002R/0168R/CM
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J.O. No. 15500 & 15800
PART A:
PART B:
STRUCTURAL DESIGN CRITERIA .
GENERAL STRUCTURAL DESIGN CRITERIA
SPECIAL REQUIREMENTS AND DESIGN
CRITERIA FOR MAJOR STRUCTURES.
STONE & WEBSTER ENGINEERING CORPORATION
DENVER, COLORADO
GENERAL STRUCTURAL DESIGN CRITERIA
STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
SECTION TITLE PAGE
PART A GENERAL STRUCTURAL DESIGN CRITERIA
1.0 GENERAL A-1
2.0 REGULATIONS, CODES, STANDARDS AND GUIDES A-4
3.0 MATERIALS A-7
4.0 DESIGN LOADS A-.10
5.0 STRUCTURAL DESIGN A-23
6.0 TABLES A-33
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
SECTION
PART B
1.0
2.0
3.0
4.0
s.o
6.0
7.0
8.0
9.0
4002R/0168R/CM
STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
(CONT'D)
TITLE
SPECIAL REQUIREMENTS AND DESIGN
CRITERIA FOR MAJOR STRUCTURES
MAIN DAM DIVERSION
MAIN DAM
SPILLWAY
POWER TUNNEL LINING, INTAKE, AND GATE SHAFT
STEEL LINER AND PENSTOCK
POWERHOUSE
TAILRACE
SUBSTATION
MIDDLE FORK AND NUKA GLACIER DIVERSIONS
PAGE
81-1
82-1
83-1
84-1
BS-1
86-1
87-1
88-1
89-1
GENERAL STRUCTURAL DESIGN CRITERIA
4002R/0168R/CM
.ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J •. 0. No. 15500 & 15800
STRUCTURAL DESIGN CRITERIA
PART A: GENERAL STRUCTURAL DESIGN CRITERIA
REVISION: 2
DATE: March 25, 1988
STONE & WEBSTER ENGINEERING CORPORATION
DENVER, COLORADO
GENERAL STRUCTURAL DESIGN CRITERIA
PART A
GENERAL STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
SECTION TITLE PAGE
1.0 GENERAL A-1
2.0 REGULATIONS, CODES, STANDARDS AND GUIDES A-4
2.1 Local, State, and Federal Codes and Regulations A-4
2.2 Industry Codes, Standards, and Specifications A-5
2.3 Miscellaneous Documents A-6
3.0 MATERIALS A-7
4.0 DESIGN LOADS A-10
4.1 Dead Loads (D) A-10
4.2 Live Loads (L) A-10
4.3 Snow and Ice Loads (S,I) A-10
4.4 Equipment Loads (M) A-ll
4.5 Hydraulic Loads (H) A-ll
4.6 Soil and Rock Loads A-ll
4.7 Wind Loads (W) A-12
4.8 Seismic Loads (E) A-13
4.8.1 General Seismic Conditions A-13
4.8.2 General Seismic Forces A-14
4.8.3 Seismic Forces on Elements A-17
4.9 Tsunami and Seiche Induced Forces A-18
4.10 Thermal Loads (T) A-18
4.11 Pipe and Cable Tray Load Allowances A-19
4.12 Roof Girder Load Allowance A-19
4.13 Column Load Allowance A-20
4.14 Bracing Load A-21
4.15 Temporary Roof Loads A-21
4.16 Crane Impact Allowance A-21
4.17 Hoist Trolley Loads A-22
4.18 Truck Loads A-22
4.19 Vibrational Loads A-22
4.20 Construction Loads A-22
5.0 STRUCTURAL DESIGN A-23
5.1 Load Combinations A-23
5.2 Stability Requirements A-24
5.3 Steel Design A-25
5.4 Concrete Design A-29
5.5 Masonry Design A-32
1
-4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
SECTION
6.0
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Table 10
ATTACHMENTS
TABLES
TABLE OF CONTENTS
(CONT'D)
TITLE
Selected Material Weights
Minimum Live Loads for Floors and Decks
Estimated Equipment Weights
Miscellaneous Equipment Loads
Snow Loads
Wind Pressures -Speed V = 100 mph,
I= 1.0, Exposure B
Wind Pressures -Speed V = 100 mph,
I = 1.0, Exposure C
Wind Pressures -Speed V = 120 mph,
I= 1.0, Exposure B
Wind Pressures -Speed V = 120 mph,
I = 1.0, Exposure C
Wind Load Importance Factors
PAGE
A-33
A-33
A-34
A-36
A-38
A-38
A-39
A-40
A-41
A-42
A-43
Attachment A -Mean Horizontal Response Spectra
11
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-1
PART A
GENERAL STRUCTURAL DESIGN CRITERIA
1.0 GENERAL
This document provides structural design cri.teria necessary to design the
Bradley Lake Hydroelectric Project. Separate from this criteria are design
criteria set by R & M Consultants, Inc. (R & M) for roads, bridges, camp
facilities, barge and harbor facilities and criteria set by Dryden and
LaRue, Inc. (D & L) for transmission systems. Supplemental to this
criteria are General Project Information and Civil Design Criteria,
Geotechnical Design Criteria,_ and. Hydraulic Design Criteria.
The Bradley Lake Project is being designed by Stone & Webster Engineering
Corporation (SWEC) for the Alaska Power Authority. The project is located
in the southern end of the Kenai Peninsula.approximately 27 miles northeast
of Homer, Alaska and approximately 105 miles south of Anchorage, Alaska.
The project witl initially develop a nominal 90 MW capacity. The
powerhouse will be located on the Kachemak Bay with a tunnel to Bradley
Lake. The existing natural . lake level is at elevation 1080. The
electricity produced will be transmitted to Homer,. the Kenai Peninsula, and
Anchorage. The project will be designed so as not to preclude the
installation of a third unit with a resulting total project capacity of 135
MW.
The project includes the following principal features:
1. A concrete faced rockfill dam locat.ed at the natural outlet of Bradley
Lake;
2. A concrete ungated gravity ogee spillway;
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-2
3. A horseshoe shaped diversion tunnel approximately 400 ft long, with
gatehouse and gateshaft, steel penstock, outlet portal structure, and
excavation of the Bradley River channel immediately downstream of the
tunnel and dam;
4. A power tunnel approximately 11 ft diameter by 19,000 ft long between
Bradley Lake and the powerhouse;
5. An intake structure with a removable trashrack and bulkhead gates at
the inlet to the power tunnel;
6. A gatehouse and gateshaft located in the upstream portion of the power
tunnel;
7. Diversion works on the Middle Fork of the Bradley River and at the
terminus of the Nuka Glacier;
8. A steel penstock and steel liner located at the downstream portion of
the power tunnel to the powerhouse;
9. An above ground powerhouse, containing two 45 MW generators with
Pelton turbines and associated equipment, with capabilities for
expansion to three units;
10. A tailrace channel discharging into Kachemak Bay, located adjacent to
the powerhouse;
11. A Compact Gas Insulated Substation (CGIS) with 115 kV transformers
located adjacent to the powerhouse;
12. Docking and barging facilities and an airstrip at the Kachemak Bay;
13. Maintenance and storage facilities;
14. Both permanent and construction camp facilities;
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-3
15. Access roads within the project site;
16. Permanent housing facilities for operating personnel; and
17. A 115 kV transmission line with intertie switching station at the
Homer-Soldotna transmission system.
Work under items 12, 13, 14, 15 and 16 will be performed by R & M
Consultants and work under item 17 will be performed by Dryden and LaRue,
Inc., (subcontractors to Stone & Webster Engineering Corporation).
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-4
2.0 REGULATIONS, CODES, STANDARDS, AND GUIDES
Unless otherwise stated, the design of all structures shall conform to the
latest editions of the applicable codes and specification listed below.
2.1 LOCAL, STATE, AND FEDERAL CODES AND REGULATIONS
AAC
OSHA-AK
OSHA-US
DOT/PF 1982
4002R/0168R/CM
Alaska Administrative Code, Section 13AACSO,
(incorporates UBC provisions for Alaska State building
code requirements).
General Safety Code, Vol. I, II, and III, Occupational
·Safety and Health Standards, Alaska Department of Labor,
Division of Occupational Safety and Health, 1973 and as
amended in 1983 and the Construction Code, 1974 and as
amended in 1982.
U.S. Department of Labor Occupational Safety and Health
Administration, OSHA 2206 General Industry Standards (29
CFR 1910), and OSHA 2207 Construction Industry (29 CFR
1926/1910), as supplement to the State of Alaska's
General Safety Code.
Alaska Department of Transportation and Public
Facilities, Design Standards for Buildings.
GENERAL STRUCTURAL DESIGN CRITERIA
A-5
2.2 INDUSTRY CODES, STANDARDS, AND SPECIFICATIONS
AASHTO-HB
ACI 302.1R
ACI 315
ACI 318
ACI 336.3R
AISC
AISI
AWS Dl.l
AWS D1.4
SJI
UBC
4002R/0168R/CM
1978
1980
1980
1983
1972
Standard specifications for Highway Bridges; American
Association of State Highway and Transportation .
Officials (AASHTO).
Guide to Concrete Floor and Slab Construction.
Manual of Standard Practice for Detailing Reinforced
Concrete Structures.
Building Code Requirements for Reinforced Concrete
(ACI 318).
Suggested Design and Construction Procedures for
Rl980 Pier Foundations.
1980
1968
1985
1985
1986
1985
Manual of Steel Construction (8th Edition)
Specifications for the Design of Cold-Form Steel
Structural Members with Commentary; American Iron and
Steel Institute (AISI).
Structural Welding Code; American Welding Society
(AWS).
Reinforcing Steel Welding Code; AWS.
Standard Specifications, Load Tables and Weight
Tables; Steel Joist Institute (SJI).
Uniform Building Code; International Conference· of
Building Officials.
GENERAL STRUCTURAL DESIGN CRITERIA
A-6
2.3 MISCELLANEOUS DOCUMENTS
SEAOC
R & M
D & L
SWEC
Criteria
4002R/0168R/CM
1980 Recommended Lateral
Commentary; Structural
California, 1980 Edition.
Force Requirements
Engineers Association
and
of
Civil & Facilities Design Criteria, Bradley Lake
Criteria Project, R & M Consultants, Inc., Anchorage,
Alaska.
Transmission Facilities Design Criteria, Bradley
Criteria Lake Project, Dryden and LaRue, Inc.
Bradley Lake Hydroelectric Project:
General Project Information and Civil Design Criteria
Geotechnical Design Criteria
Hydraulic Design Criteria
GENERAL STRUCTPRAL DESIGN CRITERIA
A-7
3.0 MATERIALS
Materials listed below and conforming to the referenced ASTM designation
will be specified on the project. For specific design requirements see
Section 5.0, Structural Design, and Part B of this criteria.
A. STEEL
Structural Steel
High-strength steels where
specified
Stainless Steel Plate
Stainless Steel Sheet
B. Bolts, Nuts, and Washers
ASTM A36
ASTM A572, Grade 50
or ASTM A588, Grade 50
ASTM Al67, Type 304 or
Type 316
ASTM A167, Type 304 or
Type 316
High-strength Bolts for Joints ASTM A325, Type 1
High-strength Alloy Bolts for
Joints
Unfinished Bolts for Anchor
Bolts and Miscellaneous
Connections
High-strength Anchor Bolts
4002R/0168R/CM
ASTM A490, with yield
strength between 130 ksi
min and 145 ksi max
ASTM A307, Grade B
ASTM A193, Grade B7
GENERAL STRUCTURAL DESIGN CRITERIA
c.
D.
E.
F.
H.
I.
J.
Corrosion-resistant Bolts, Nuts
and Washers for Removable
Structural Members
Crane Rail and Standard
Accessories
Steel Floor Grating and
Stair Treads
Roof and Floor Decking
Weld Filler Metal
Checkered Floor Plate
Pipe Handrail
Ladders
Safety Chain
ASTM A193, Grade B8 Bolts
ASTM Al94, Grade 8 Nuts
ASTM A304 Washers
A-8
ASTM A759, attached with
pressed clips and reversible
fillers for a tight fit.
Joint Bars ASTM A3
ASTM A569, Welded Bar
Grating
ASTM A446 and coated with
zinc coating conforming to.
ASTM A525
AWS Dl.l and Table 4.1.1
therein
ASTM A36 with a symmetrical
raised diamond pattern
Sch. 40, ASTM A53 Grade B, or
ASTM ASOO Grade B, of
comparable section and
strength
ASTM A36
ASTM A413, Proof Coil Class
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
K.
L.
M.
N.
o.
P.
Q.
Cement
Aggregates
Reinforcing Steel
Welded Wire Fabric
Pipe and Floor Sleeves
for Penetrations
Steel Studs
Rock Anchors
4002R/0168R/CM
A-9
Type II, low alkali Portland
Cement conforming to ASTM ClSO
ASTM C33
ASTM A615, Grade 60,
including Supplement Sl
ASTM Al85
ASTM AS3, Grade B,
Schedule 40 or ASTM A36
plate material
By Nelson Stud Welding Co.,
or equal
See Geotechnical Design
Criteria
GENERAL STRUCTURAL DESIGN CRITERIA
A-10
4.0 DESIGN LOADS
4.1 DEAD LOADS (D)
Dead loads consist of the weight of all permanent construction.
Refer to Table 1 Selected Material Weights.
4.2 LIVE LOADS (L)
Live loads will consist of uniform surface loads or equivalent
point loads developed to represent loading effects due to the
movement of materials, equipment or personnel applied on a
temporary basis. Loads will be identified as live loads when
the i tern imposing the load is not rigidly or permanently fixed
to a structure. Live loads are assumed to include adequate
allowance for ordinary impact conditions.
Table 2 in Section 6.0 lists uniform floor live loads to be used
unless otherwise specified. Uniform floor live loads may be
omitted in regions where actual equipment loads are provided and
exceed the specified floor loading. Where equivalent uniform
live, floor or point loads are used to represent equipment
weights, actual loads shall be checked against assumed loads
when information is available.
Live loads for floors and roofs shall be designated on the
drawings under the applicable floor or roof plan.
4.3 SNOW AND ICE LOADS (S,I)
For purposes of design, snow and ice loading will be consid-
ered to occur for a minimum of 6 months out of the year.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-ll
Snow loads as listed in Table 5 are cj.eveloped for the project
based on the Department of the Army's technical document ETL
lll0-3-31.7 and shall be used for buildings and structures.
Effects of removing half the snow from any portion of the loaded
area shall be investigated for all roofs. This condition
simulates loss of snow from a portion of roof due to natural or
man made causes.
The effects of ice loads on hydraulic structures as specified in
Part B of this Design Criteria shall be considered.
4.4 EQUIPMENT LOADS (M)
Selected equipment weights and estimated loads are listed in
Tables 3 and 4. Evaluate known equipment loads for empty weight
(dead weight of equipment), operating weight (full contents),
and operational loadings (torques, etc.). Use Table 2 load
information when equipment information is not available.
Lifting hooks for equipment shall consider a 33 percent increase
in lifting load for impact.
4.5 HYDRAULIC LOADS (H)
Hydrostatic and hydrodynamic loads are those imposed on
structures by water due to pressure, flow or earthquake. Refer
to the Hydraulic Design Criteria, the Geotechnical Design
Criteria, and Part B of this Design Criteria for specific loads.
4.6 SOIL AND ROCK LOADS.
Refer to the Geotechnical Design Criteria for specific loads.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-12
4.7 WIND LOADS (W)
Wind loads developed for the Bradley Lake Project are based on
the 1985 UBC formula for wind pressure:
p = C C q I e q s (UBC Chap. 23i Eq. 11-1)
Where:
p =
c = e
c = q
Design wind pressure
Combined height, exposure and gust
coefficient as given in UBC Table No. 23-G
factor ·
Pressure coefficient for the structure or portion
of structure under consideration as given in UBC
Table-No. 23-H
qs = Wind stagnation pressure at the standard ·height of
30 ft as set forth in UBC Table No. 23-F
I = Importance factor as set forth in UBC Section
23ll(h).
For applicable design factors refer to Tables 6 through 9.
1. Wind Load Application:
Wind loads shall be applied orthogonally to buildings and
structures in only one direction at a time. For tanks or
structures supported on four legs in an elevated position
wind load shall be applied diagonally. Wind loads shall not
be combined with earthquake loadings; however, they shall be
applied in combination with snow loads.
2. Exposure Category and Importance Classification:
4002R/0168R/CM
Wind pressures for the identified exposure condition of-
Tables 6 through 9 shall be multiplied by the appropriate
importance factor developed for the project and listed in
Table 10.
GENERAL STRUCTURAL DESIGN CRITERIA
4.8
4.8.1
A-13
SEISMIC LOADS (E)
General Seismic Conditions
Structures shall be subjected to seismic event loads in
accordance with the following basis of criticality:
Description
Non-Critical
Those structures which house
or support equipment or sys-
tems which, if _damaged during
a major seismic event, could-
be replaced or repaired within
six months or are not critical
to the continued operation of
the hydroelectric facility.
Critical
Those structures which house
or support equipment or systems
considered critical to the
continued operation of the
hydroelectric facility, and
which would take more than six
months to repair or replace or
would be prohibitive in cost to
repair or replace, if damaged
·during a major seismic event.
Structure
All structures not listed
in critical or hazardous
categories.
Main Dam Diversion Tunnel
and Gatehouse
Power Tunnel including
Intake and Gate Shaft
Powerhouse Structures
Penstock
Spherical Valves
Main Dam
Spillway
Substation
4002R/Ol68R/CM GENERAL STRUCTURAL DESIGN CRITERIA
4.8.2
Hazardous
Those structures which house
or support equipment or systems
containing materials such as
acids, caustics, chemicals or
flammables which, if damaged,
could be hazardous to personnel,
the environment, or to the
continued operation of the hydro-
electric facility.
General Seismic Forces
A. Non-Critical Structures
1. Force Computation·
Chemical Tanks,
Fuel Tanks, Pumps,
Caustic and Acid Tanks,
Chlorine Systems,
Transformers
A-14
Non-critical structures shall be designed for effects of
a static horizontal seismic acceleration of 0" 35g
represented by:
v = 0.35 w
Where:
V = Total lateral force or shear at base
W = Total dead load, including partition loads and
equipment weight or 25 percent of live load
Unless otherwise stated," allowable stresses may be
increased by 33 percent for this seismic condition.
4002R!0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
4002R/0168R/CM
A-15
2. Force Distribution
Distribution of forces shall follow UBC formula:
(UBC Chap. 23, Eq. 12-5)
Where:
Ft = 0.07TV (Ft need not exceed 0.25 V and may be
considered as zero where T = 0.7 sec, or less);
T = 0.05 hn
D
(UBC Chap. 23, Eq. 12-3A)
F i = Remaining portion of total base shear distributed
over the height of the structure including level n
according to UBC formula 12-7;
F = X
Where:
w.w l X
h.h h
1 n x
(V-Ft)
Level n
D
w h X X (UBC Chap. 23, Eq. 12-7)
= That portion of W which is located at or
is assigned to level i or x, respectively;
= Height in feet above base to level i, n,
or x, respectively;
= That level which is upper most in the
main portion of the structure;
= The dimension of the structure, in feet
in a direction parallel to applied force
(not to be confused with "D" used for
dead load of Section 4.1, herein).
GENERAL STRUCTURAL DESIGN CRITERIA
A-16
3. Force Applications
Horizontal seismic forces shall be applied orthogonally
to rectangular structures. Application of force shall be
made in each direction separately. Where tanks or towers
are elevated, application of seismic forces shall be made
diagonally and shall consider affects of liquid
movement. Seismic forces shall not be applied
concurrently with wind forces. Under certain
circumstances seismic forces shall consider live load and
effects of snow.
4. Vertical Forces
In addition to seismic effects due to horizontal ground
motion, structures shall be designed for the effects of
vertical seismic acceleration equal to 2/3 the horizontal
acceleration. Except as otherwise stated, horizontal and
vertical accelerations may be considered to act
independently.
B. Critical Structures
4002R/0168R/CM
Development of seismic ~orces for critical structures shall
follow the recommendations set forth under Part B of this
Criteria. Unless otherwise stated, critical structures
shall be designed for all of the conditions under Section
4.8.2(A) without any increase in allowable stresses, and
additionally for a static horizontal force of:
v = 0.75 w
GENERAL STRUCTURAL DESIGN CRITERIA
4.8.3
A-17
applied in a manner similar to Section 4.8.2 (A.), except
that-allowable stresses may be increased by 50 percent for
this seismic condition. Vertical forces shall be applied in
accordance with Section 4.8.2 (A.4).
Where specified, critical structures shall consider
amplification of acceleration in accordance with the Project
Response Spectra (Attachment A).
C. Hazardous Structures
Structures for hazardous material shall be designed in a
manner similar to Section 4.8.2 (B), except that:
a. Spill containment barriers may be· designed for a static
force of V = 0.35W with no increase in allowable stresses.
b. Tanks or towers on elevated support legs shall consider
the seismic effects of motion of the mass of liquid con-
tained within the vessel. Calculation and application of
seismic induced forces shall follow Chapter 11 of Navy
document NAVFAC P-355, or Chapter 6 of TID 7024 Nuclear
Reactors and Earthquakes.
Seismic Forces on Elements
Unless otherwise specified in Part B of this Design Criteria,
parts or portions of structures and anchorage of nonstructural
components, such as equipment or architectural items, to the
main structural system shall be designed for lateral forces in
accordance with the following formula:
F = ZIC W p p p
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-18
Where: F = Lateral forces on a part of the structures and in p
the direction under consideration;
I = 1.0 Importance Factor, except for hazardous
materials where I = 2.0;
c = Numerical p Coefficient as specified in UBC Table
No. 23-J;
z = 1.0 (UBC Zone 4);
w = p Weight of object under consideration.
4.9 TSUNAMI AND SEICHE INDUCED FORCES
Refer to Part B for specific applications.
4.10 THERMAL LOADS (T)
Structures exposed to large temperature changes shall be designed to
consider the affect of induced stresses. Design shall consider the
following extreme exposure conditions:
Minimum Temperature
Maximum Temperature
Modified temperature conditions may apply to enclosed structures,
and will be identified in Part B for specific situations.
Change in length (see p. 6-7, AISC Manual) will be based on a
coefficient of expansion of 0.00065/100°F,
0.00055/100°F, for concrete.
for steel, and
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-19
4.11 PIPE AND CABLE TRAY LOAD ALLOWANCEs·
Areas of heavily concentrated piping or cable tray runs shall be
designed for that increased loading.
A general load allowance shall . be applied to the midspan of all
steel framing members to account for miscellaneous pipe and cable
tray loads, as follows:
Member
Girder
Stringer
12 in. depth or less
2 kips·
2 kips
The following shall apply:
Over 12 in. depth
6_kips
3 kips
1. Design for the actual loads where information is available.
2. Platform bracing angles, main bracing, beams less than W8, and
c~annels shall not receive any load allowances and shall not be
hung with pipes or cable trays.
3. Load allowances shall not be added to the reactions at girders
or columns for the purposes of designing connecting members,
however added load shall be used for design of connections.
4. On vertical pipe runs where two hangers are used to carry the
load at a single clamp, the steel support shall be designed to
carry the full pipe load from either hanger.
5. Where heavy pipe loads are hung from steel beams or girders, the
hanger prying action on the beam flange shall be checked.
6. -Applicable hydrostatic test loads shall be considered for pipe
supports or support~ng structure.
4.12 ROOF GIRDER LOAD ALLOWANCE
Main roof girders spanning over the powerhouse generator floor shall
be deslgned for a 12 kip contingency load applied uniformly over the
length of the girder.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-20
4.13 COLUMN LOAD ALLOWANCE
A. Vertical Allowance
For preliminary column sizing, a 15 kip load allowance shall be
applied to the tops of columns to take care of hung pipe, ducts,
miscellaneous equipment, and loads not yet defined.
Column loads shall be checked against actual loads. Calculated
reactions. shall include thermal, pipe restraint, wind, and
earthquake forces as applicable. If the actual loads exceed the
known loads plus load allowance, the columns· shall be reanalyzed
and, if necessary increased in size. The column sizing need not be
adjusted down in size unless loads have been grossly overestimated.
B. Horizontal Support Allowance
Horizontal beams or trusses shall be used to prevent columns from
buckling. Horizontal struts shall be designed for an axial load of
not less than 10 kips or a percentage of the actual column load,
whichever is greater:
Support Column
L/r
140 max
141 to 200
Column Load Percentage
2
3
Where horizontal support trusses are used, the truss depth should
equal about one-tenth the span and the web system members should be
a minimum 3 1/2 in. by 3 in. by 5/16 in. double angles, or a
T-section of similar properties.
Where wind loads are carried by the same horizontal support system,
the framing shall be designed for either wind or stability loading,
whichever is largest, but the loads shall not be additive.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-21
4.14 BRACING LOAD
Bracing shall be designed for no less than a 10 kip axial load.
4.15 TEMPORARY ROOF LOADS
Roof member sizes may be increased to suit temporary use in lifting
heavy equipment. Such members would become part of the permanent
roof framing. For temporary conditions, a one-third increase in
working stresses will be allowed.
4.16 CRANE IMPACT ALLOWANCE
·Powerhouse cranes have relatively low hoisting speeds. and DC
controls, which provide for more precise handling. Values to be
used for impact and horizontal forces for the powerhouse crane shall
be as follows:
Rated Load, *Impact
Tons %
160 10
'l'.-.'cLateral
Force, %
10
~c-:n'cLongi tudinal
Force, %
10
* Based on maximum wheel loads (Refer to Table 4)
~k Based on rated loads plus trolley weight applied at top of crane
rail, half on each.side.
~ric-k Based on maximum wheel loads applied at top of rail.
Impact and horizontal forces shall be included in the design of
columns but not the foundation. Side thrust and impact shall not be
considered simultaneously.
Neither earthquake nor wind loads shall be considered acting
simultaneously with crane live loads in designing columns and
foundations. Full wind or seismic shall be considered acting with
crane dead load.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A--22
4.17 HOIST TROLLEY LOADS
Supports for hoist monorails shall be designed to include the
trolley, hoist, and monorail loads. Impact for motor-operated
hoists shall be 25 percent of the lifting capacity added to the
hoist and trolley load.
4.18 TRUCK LOADS
Floor areas and bridges subject to truck loads shall be designed, as
a minimum, for 300 psf or an HS25 truck loading plus 10 percent
impact, whichever governs. Wheel loadings for stator or transformer
transport shall consider axle loadings of 32,000 lb per axle with a
minimum 4 · ft axle spacing, or an 800 psf uniform live load,
whichever governs.
4.19 VIBRATIONAL LOADS
It is assumed that most equipment will be properly bedded and
anchored or isolated so as to preclude significant vibration induced
loads being imposed on structures, however, specific conditions may
require the application of dynamic loads due to vibrating equipment.
4.20 CONSTRUCTION LOADS
A 25 psf live load shall be added to all floor construction loads to
account for men and equipment during construction. Where
construction conditions are to be evaluated, a O.lOg horizontal
ground accelaration shall be applied pseudostatically for seismic
conditions during construction. Additional construction loads may
be applicable for special applications.
A one-third increase in working stresses will be allowed for
temporary construction loads.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-23
5 •. 0 STRUCTURAL DESIGN
5 •. 1 LOAD COMBINATIONS
Load combinations for specific structures will be identified in Part
B of this document. Should an area not be identified, and in the
absence of other instructions, the following loading combinations
will be observed:
A. For Dead Load, Live Load, Wind, Seismic and Snow
D + L
D + L + w
D + L + E
D + L + s
D + L + W + o.sos
D + L. + O.SOW + S
D + L + E + O.SOS
A 1/3 increase in allowable stresses may be used for
combinations including wind per the applicable codes; allowable
stresses for seismic conditions shall be as defined herein.
B. For Equipment Supports
M (empty) + W or E
M (operating) + L
M (operating) + L + (W or E)
M (flooded or testing load)
Critical load combinations may vary for specific pieces of
equipment.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-24
5.2 STABILITY REQUIREMENTS
Specific conditions for individual structures are elaborated in Part
B of the criteria. Where criteria are not given, the following
stability criteria shall apply:
A. Overturning
The factor of safety against overturning shall be at least 1.5,
except that for the extreme seismic event the factor of safety
may be reduced to 1.05.
B. Sliding
The factor of safety against sliding shall be at :least -1.5,
except that for the extreme seismic event the factor of safety
may be . reduced to 1.05. The coefficient of friction on rock
shall be in accordance with the Geotechnical Design Criteria.
Passive pressure shall not be used to resist horizontal forces
unless specifically allowed for in the geotechnical design.
C. Flotation
The factor of safety against flotation shall be at least 1.1
under the "construction" condition and 1. 5 under "completed"
condition. The stabilizing force shall be the dead weight of
the structure alone. Live load shall not be considered as
assisting resistance.
D. Anchoring Structure
In lieu of the above given factors of safety, structural
anchorage to rock or foundation may be used to resist forces
tending to upset the stability of a structure. The structure
shall be anchored so as to resist the excess overturning moment;
sliding force, and/or flotation force without exceeding the
allowable stresses for the materials used. Type of anchorage
system shall be determined on a case-by-case basis. Refer to
Part B of this criteria.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-25
5.3 STEEL DESIGN
A. Connections
Field connections with high strength bolts shall be bearing type
connections, except for members having reversible wind or
seismic stresses where friction type joints shall be required.
Connections shall be designed to effectively include the prying
action forces where applicable.
Bolted connections of structural steel members shall be made
with 7/8 in. or 1 in. diameter ASTM A325 Type 1, Class E, high
strength bolts; 1 1/8 in. diameter ASTM A490 high strength bolts
may be considered for speci~l applications.
Bracing connection design loads shall be shown on the drawings.
Reactions for design of framed beam connections shall be shown
on the drawings if they exceed the shear developed from one half
the total uniform load capacity of the beam in accordance with
AISC. In addition, the following minimum connections are
specified for the fabricator's use:
Beam
Depth
(in.)
36
33
30
27
24
21, 18,' 16
14, 12
10, 8
7 and under
Number of Bolts in
Outstanding Legs· of
Connection Angles
.18
16
14
12
10
a·
6
4
2
The minimum connection allowed shall be a 2 bolt connection.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-26
Moment connections shall be designed to develop the full plastic
capacity of the beam, unless otherwise specified.
Stairways and girts shall use 3/4 in. diameter ASTM A307 bolts.
B. Floor Grating and Checkered Plate
Grating for floor areas, walkways and hatches shall be
galvanized and shall have as a minimum 1-1/4 in. deep x 3/16
inch thick bearing bars spaced at 1-3/16 in. Actual depth shall
be controlled by design load and span.
Checkered floor plate shall be a minimum 5/16 in. thick, except
that 1/8 in. thick checkered plate may be used when-welded to
the top of grating.
C. Handrail, Guardrail, and Kickplates
Handrail shall be nominal 1-1/2 in. diameter, Schedule 40 pipe.
Post spacing shall not be greater than 8 ft. A top, bottom and
center rail shall be provided at the powerhouse. Guardrail
shall be nominal 2 in. diameter, Schedule 40 pipe and will
otherwise meet the handrail requirements. Pipe handrail and
guardrail connections will be of welded construction.
Four-inch high kick plates shall be provided around all clear
openings greater than 1 in. and along standard handrails.
D. Steel Floor Forms and Roof Deck
Steel floor forms shall be a minimum 1-1/2 in. deep, 20 gauge
roll formed corrugated metal deck. Steel roof deck shall be a
minimum 3 in. deep, 20 gauge roll formed metal deck. Should
slope of roof be adjusted to reduce load, gauge may be reduced
to 22 gauge, if warranted.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-27
Steel floor forms and roof decks shall be attached to supporting
framing by welding with minimum 3/4 in. diameter fusion welds
(puddle), or by use of approved power actuated fasteners.
E. Crane Rails and Stops
Size, weight and shape of crane rails and accessories shall be
per the AISC Manual, based on the rail size specified by the
crane manufacturer. Type of crane stops shall meet the crane
manufacturer's recommendations.
F. Welding Materials
In general, E70XX welding electrodes shall· be used.
welding electrodes may be specified where required.
G. Deflections
Special
Deflections shall not exceed the following deflection limitation
ratios multiplied by the span length:
Member Type or Item
1. Primary Structural
Framing member
2. Secondary Structural
Framing member (Purlins,
girts, etc.)
3. Exterior Wall and Roof
panels
4. Metal floor form with
concrete slab
5. Grating
4002R/0168R/CM
Deflection
Limitation
1/240 (maximum)
1/180 (maximum)
1/180 (maximum)
1/360 (maximum)
1/4 in. for 100
psf live load
GENERAL STRUCTURAL DESIGN CRITERIA
Member TYpe or Item
6. Checkered floorplate
7. Steel Decking
8. Roof Joist (per SJI)
9. Floor Joists (per SJI)
10. Monorails
11. Crane Girders:
Vertical Deflection
Lateral Deflection
H. Minimum Member Sizes
Deflection
Limitation
1/100 (live load)
1/240 (total load)
1/360 (maximum)
1/360 (maximum)
1/500 (maximum)
1/1200 (maximum)
1/400 (maximum)
A-28
Minimum member sizes allowed shall be based on the follo~;ng:
Minimum Dimensions (in.)
Flange Flange Member or Web
Member TYpe Width Thickness Leg Depth Thickness
Wide Flange, 4 1/4 6 1/4
S and M Shapes
Channels 2 1/4 6 3/16
Angles 2 1/4 2 1/4
"S" shapes shall be used for monorails.
Minimum size stringer for stairs shall be C9xl3.4.
I. Special Material Considerations
Design of structural steel members subjected to fatigue induced
by vibration or repetitive loading shall follow the
recommendations of the AISC Specification S326.
Where cold temperature conditions must be considered, the
metallurgy of the material must be examined and specified for
toughness.
4002R/0168R/CM GENERAL STRUC~L DESIGN CRITERIA
A-29
5 .,4 CONCRETE DESIGN
A. General
Concrete structures shall be designed in accordance with ACI
318-83. Ultimate Strength Design procedures should be used,
unless directed otherwise.
Generally, load combinations follow the recommendations of ACI
318-83, Chapter 9. Special load combinations identified in Part
B shall be used where applicable.
The seismic detailing provisions of ACI 318, Appendix A shall be
considered in the design, for concrete buildings and frame
structures.
B. Concrete
The minimum specified compressive strength to be used for design
shall be as identified in Part B for specific structures. Where
Part B does not apply, a minimum specified 28 day compressive
strength of 4,000 psi shall be used for purposes of design.
Unless otherwise specified, nominal maximum size of aggregate
shall be 1-1/2 inches. Where required due to conjested
reinforcing steel or placing requirements, 3/4 inch nominal
maximum aggregate size may be specified.
The minimum specified concrete compressive strength shall be
identified on the drawings for each structure and areas
requiring special concrete mixes shall be clearly shown.
4002R/Ol68R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-30
C. Reinforcement
Deformed reinforcing bars having a yield strength (f ) of 60 y
ksi shall be used. In addition, the following shall be observed:
1. Minimum ties shall be No. 4 rebar.
2. All isolated circular columns shall be spirally reinforced.
3. Minimum reinforcing allowed shall be No. 4. Try to keep
rebar sizes below No. ll's.
4. Lengths should be kept to 40 feet maximum.
5. In order to keep the number of different sizes .of
reinforcing bars used to a minimum, the following rebar
sizes should be used in design:
main steel: #4, #6, #8, #9, #11
ties: #4, #s
6. Uncoated rebar shall be used except where specifically noted
otherwise. Epoxy coated rebar shall be used only in
specified locations.
D. Concrete Cover for Reinforcement
The minimum clear concrete cover for reinforcement shall be as
follows:
Concrete exposed to fresh or salt water
Concrete cast against rock or earth
Exterior walls:
Outside face
Inside face
Floor slabs and interior walls
Beams and columns
3"
3"
3"
2"
2"
1-1/2"
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-31
E. Construction Joints
Where possible, roughened construction joints should be used in
lieu of keyed joints. Load transfer thru joints should be
checked in accordance with ACI 318, Section 11.7,
Shear-friction. Keyed joints may be used where shear forces
warrant.
Construction joints and control joints should be clearly shown
on the drawings. ·
, F.· Drilled Concrete Anchor Bolts
Drilled concrete anchor bolts shall be friction type anchors
designed in accordance with Stone & Webster Structural Technical
Standard STS-ACll-2-1.
G. Floor Forms
Metal floor deck used as floor forms must .be checked for load
and span limitations. Keep span within deck manufacturer's
recommended limitations wherever possible.
H. Foundations
·Foundation depths may be effected due to frost. ·Depths of
foundations shall be in accordance with the Geotechnical Design
Criteria and calculations. Siting conditions may dictate the
requirements for special insulation procedures.
GENERAL STRUCTURAL DESIGN CRITERIA
A-32
I. Waterstops
In general, waterstops shall be natural rubber, synthetic
rubber, or ·polyvinyl chloride, as manufactured by W.R._ Meadows,
Inc., W.R. Grace & Co., or equal, or shall be metal waterstops.
Vertical waterstops at contraction joints shall be dumbbell
types, 6 in. or 9 in. as design dictates. Waterstops shall be
capable of resisting the maximum pressures and movements
anticipated. Cellular-type or baffle type waterstops shall not
be used. Flat metal waterstops, 1/8" x 8", ·shall be used in
vertical and horizontal construction joints. Waterstop,
reinforcing steel, and construction joint placement shall be
arranged to avoid interferences.
J. Conduit
No aluminum or aluminized conduit or fittings shall be allowed
for embedment in concrete.
K. Sleeves
Anchor bolt sleeves may be used for equipment anchor bolts.
Unless proximity to edge of concrete dictates use of steel ·pipe
sleeves, plastic sleeves are preferred and may be Wilson Anchor
Bolt Sleeves, or equal.
for column base plates.
Anchor bolt sleeves are not required
All anchor bolts shall be accurately
placed with a template prior to placement of concrete.
5.5 MASONRY DESIGN
Masonry construction shall not be used unless specifically
approved by the client.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN. CRITERIA
A-33
6.0 TABLES
TABLE 1
SELECTED MATERIAL WEIGHTS
Mass Concrete (For stability) 145
Reinforced Concrete 150
Steel 490
Water 62.4
Ice 56
Sea Water 64
I
'
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-34
TABLE 2<'r
MINIMUM LIVE LOADS FOR FLOORS AND DECKS
Area'DescriEtion AEErox. Floor El. Live Load Remarks
(ft) (psf)
Powerhouse:
Generator Floor 42 300 Check maximum
equipment loads.
Service Bay Floor 42 BOO Check vehicle
wheel loads.
Shipping loads
are 1/2 stator
ring or full
generator rotor
assembly without
coupling shaft.
Minimum HS25
wheel load.
Turbine Floor 21 300
Tailrace Deck 21 150 Check maximum gate
laydown load.
Spherical Valve & 5 300 On rock.
Runner Gallery
Control Room 42 250 Check maximum
equipment load.
Machine Shop 42 250 t·
HVAC Room 60 250
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
A-35
TABLE 2 (Continued),'c
MINIMUM LIVE LOADS FOR FLOORS AND DECKS
Area Description
!
I
Approx. Floor El.
(ft)
i
General-Buildings:
I
Meeting areas, lunch rooms,
locker facilities, office
areas
I Stairs and corridors
Miscellaneous walkways
and platforms
Storage Areas, Heavy
Storage Areas, Light
~atch Covers and Grating:
I
' I
Generator Floor
Turbine Floor
Others
42
60
42
21
Live Load Remarks
(psf)
100
100
50
250
125
300
300
Use for gate
shaft platforms.
Same as adjacent
floor load.
~Live loads shall not be reduced in accordance with UBC procedures.
14002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
TABLE 3
ESTIMATED EQUIPMENT WEIGHTS
(Subject to verification)
i • EqUl pmen t Type
Turbine
I
Total Weight
Scroll_ Case Manifold
Rotating Parts
Runner
Shaft
I qenerator
I
i
Total Weight
Heaviest Lift (rotor and shaft with poles)
Stator, one half
Lower Bearing & Bracket
Upper Bearing Bracket
+ransformer 115 kV
I
Transformer with oil
Shippil).g weight
Spherical Valve
I
Total weight
Valve rotor and Trunnion
(heaviest part to be handled)
A-36
Estimated Weight
373,000 lbs.
145,000 lbs.
23 , 100 1 bs. --.
25,100 lbs.
450,000 lbs.
310,400 lbs.
80,000 lbs.
75,000 lbs.
35,000 lbs.
200,000 lbs.
150,000 lbs.
134,000 lbs.
74,700 lbs.
r02R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
Equipment Type
Bridge Crane
Total crane weight
Bridge weight
Trolley weight
Tailrace Gate
Control Board
4002R/0168R/CM
TABLE 3 (Continued)
ESTIMATED EQUIPMENT WEIGHTS
(Subject to verification)
A-37
Estimated Weight
165,000 lbs.
90,000 lbs.
75,000 lbs.
12,000 lbs.
23,100 lbs.
GENERAL STRUCTURAL DESIGN CRITERIA
Equipment Type
TABLE 4
MISCELLANEOUS EQUIPMENT LOADS
(Subject to verification)
Powerhouse Bridge Crane
Maximum wheel load (per wheel)
Main hook capacity
Auxiliary hook capacity
Substation Bridge Crane Capacity
Tailrace Gate Hoists Capacity
Machine Shop Hoist Capacity
TABLE 5
SNOW LOADS
Ground Snow Load
Powerhouse Roof
Powerhouse Tailrace Deck
Gatehouse Roofs
Other Building Roofs
and Covered Structures
Other Building Lower Roofs
(potential drifting)
Tailrace Canopy
Local roofing support
Overall structural support
Estimated Load
103,000 lbs.
160 ton
25 ton
3 ton
2 @ 7-1/2 ton
65 psf
85 psf
110 psf
100 psf
85 psf
110 psf
100 psf
50 psf
2 ton
A-38
4002R/Ol68R/CM GENERAL STRUCTURAL DESIGN CRITERIA
EL Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
E1. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40 I
40-60.
60-100 :
100-150
TABLE 6
WIND PRESSURES* (SPEED V = 100 MPH)
I = 1.0, EXPOSURE B, PRESSURE (psf)
CONDITION 1 -PRIMARY STRUCTURAL FRAMING
Walls Roof
Windward Leeward Leeward Windward
or Flat Slope <9:12
+15
+17
+21
+23
+27
-09 -13
-10 -15
-13 -18
-14 -20
-17 -24
CONDITION 2 -ELEMENTS AND COMPONENTS
(Enclosed Building, Roof Slope <9:12)
Walls
-13
-15
-18
-20
-24 -
Roof
Canopy End
or Ridges/
Eave Eave
Pressure Suction Parapets
Wall
Corners Suction Overhang Corners
+22 -20 24 -36 -20 -51 -55
+25 -23 27 -42 -23 -58 -63
+31 -29 34 -52 -29 -73 -78
+34 -32 37 -57 -32 -80 -86
+41 -37 44 -68 -37 -95 -101
CONDITION 3 -ISOLATED OBJECTS & MISC. STRUCTURES
A-39
Interior
Ridges/
Eaves
w/o
Overhang
-36
·-42
-52
-57
-68.
Tanks and Solid Towers
Sg/Rect Hex Oct Round Ellipt.
Open Frame·
Towers
Signs, Pole and
Minor Structures
26
29
36
40
47
20
23
29
32
37
15
17
21
23
27
36
42
52
57
68
26
29
36
40
47
*See Notes for Tables 6 through 9
4005R/0168R GENERAL STRUCTURAL.DESIGN CRITERIA
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
' 100-150
~csee Notes
4005R/0168R
for
TABLE 7
WIND PRESSURES~c (SPEED V = 100 MPH)
I = 1.0, EXPOSURE C, PRESSURE (psf)
CONDITION 1 -PRIMARY STRUCTURAL FRAMING
Walls Roof
Windward Leeward Leeward
or Flat
+25 -16 -22
+27 -17 -24
+31 -20 -27
+33 -21 -29
+37 -23 -33
CONDITION 2 -ELEMENTS AND COMPONENTS
(Enclosed Building, Roof Slope <9:12)
Windward
Slope <9:12
-22
-24
-27
-29
-33
A-40
Roof
Interior
Canopy End Ridges/
_or Ridges/ Eaves
Walls Wall Eave Eave w/o
Pressure Suction Parapets Corners Suction Overhang Corners Overhang
+37 -34 41 -62 -34 -,-87 -94 -62
+41 -37 44 -68 -37 -95 -101 -68
+47 -43 51 -78 -43 -109 -ll7 -78
+50 -46 54 -83 -46 -117 -125 -83
+56 -52 61 -94 -52 -131 -140 -94
CONDITION 3 -ISOLATED OBJECTS & MISC. STRUCTURES
Tanks and Solid Towers Open Fr arne" Signs, Pole and
Sq Rect Hex Oct Round Ell i pt. Towers Minor Structures
44 34 25 62 44
47 37 27 68 47
55 43 31 78 55
58 46 33 83 58
66 52 37 94 66
Tables 6 through 9
GENERAL STRUCTURAL DESIGN CRITERIA
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft:)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40
40-60
60-100 '
100-150
'
TABLE 8
WIND PRESSURES~' (SPEED V = 120 MPH)
I = 1.0, EXPOSURE B, PRESSURE (psf)
CONDITION 1 -PRIMARY STRUCTURAL FRAMING
Walls Roof
Windward Leeward Leeward Windward
or Flat Slope <9:12
+21 -13 -18
+24 -15 -21
+30 -18 -26
+33 -20 -29
+39 -24 -34
CONDITION 2 -ELEMENTS AND COMPONENTS
(Enclosed Building, Roof Slope <9:12)
Walls
Pressure Suction Parapets
Wall
Corners Suction
+31 -29 34 -52 -29
+36 -33 39 -59 -33
+44 -41 48 -74 -41
+49 -45 53 -82 -45
+58 -53 63 -96 -53
CONDITION 3 -ISOLATED OBJECTS & MISC. STRUCTURES
-18
-21
-26
-29.
-34
Roof
Canopy End
or Ridges
E;ave Eave
Overhang Corners
-73 -78
-83 -89
-104 -lll
-ll4 -122
-135 -144
A-41
Interior
Ridges
Eaves
w/o
Overhang
-52
-59
-74
-82
-96
Tanks and Solid Towers Open Frame Signs, Pole and
Sq/Rect Hex/Oct Round/Ellipt. Towers Minor Structures
36 29 21 52 36
41 33 24 59 41
52 41 30 74 52
57 45 33 82 57
67 53 39 96 67
*See Notes for Tables 6 through 9
j
4005R/0168R GENERAL STRUCTIJRAL DESIGN CRITERIA
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
El. Above
Grade (ft)
0-20
20-40
40-60
60-100
100-150
TABLE 9
WIND PRESSURES* (SPEED V = 120 MPH)
I = 1.0, EXPOSURE C, PRESSURE (psf)
CONDITION 1 -PRIMARY STRUCTURAL FRAMING
Walls Roof
Windward Leeward Leeward
or Flat
+36 -22 -31
+39 -24 -34
+44 -28 -39
+47 -30 -41
+53 -33 -47
CONDITION 2 -ELEMENTS AND COMPONENTS
(Enclosed Building, Roof Slope <9:12)
Windward
Slope <9:12
-31
-34
-39
-41 .
-47-: ..
A-42
Roof
Interior
Canopy End Ridges/
or Ridges/ Eaves
Walls Wall Eave Eave w/o
Pressure Suction Parapets Corners Suction Overhang Corners Overhang
+53 -49 58 .:..89 -49 -124 -133 -89
+58 -53 63 -96 -53 -133 -144 . -96
+67 -61 72 -111 -61 -155 -166 -111
+71 -65 77 -118 -65 -166 -178 -118
+80 -73 87 -133 -73 .-187 -200 -133
CONDITION 3 -ISOLATED OBJECTS & MISC. STRUCTURES
Tanks and Solid Towers Open Frame. Signs, Pole and
Sg/Rect Hex/Oct Round/Ellipt. Towers. Minor Structures
62 49 36 89 62
67 53 39 96 67
78 61 44 111 78
83 65 47 ll8 83
93 73 53 133 93
*See Notes for Tables 6 through 9
4005R/0168R GENERAL STRUCTURAL DESIGN CRITERIA
A-43
TABLE 10
WIND LOAD IMPORTANCE FACTORS
Design
Importance Wind
Area Exposure Factor Speed (mph)
Main Dam Diversion Outlet B 1.0 120
Structures
Main Dam Diversion Gatehouse c 1.15 120
Main Dam Structures c 1.15 120
Power Tunnel Gatehouse c 1.15 120
Powerhouse and Attached Average 1.15 100
Facilities of B+C
Substation Average 1.15 100
of B+C
Nuka Diversion Structures B 1.0 120
Middle Fork Diversion B 1.0 120
Structures
Exposed Coastal Facilities c 1. 0"' 100
Miscellaneous Structures B"' l.O;'c lOO;"c
*Consult the Project Lead Structural Engineer.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
NOTES FOR TABLES 6 THROUGH 9
1. (+) Indicates a load directed inward.
(-) Indicates a load directed outward.
A-44
( ) No sign indicates load may be applied 1n any direction.
2. A structure with more than 30 percent of any one side open shall be
considered an open structure. See Uniform Building Code for wind
pressures on open structures.
3. Local pressures shall apply over a distance from the discontinuity of
10 feet or 0.1 times the least width of the structure, whichever is
smaller.
4. Wind forces on cladding connections shall be calculated ·by
multiplying the tabulated loads by a factor of 1. 5.
5. Local pressures on structural elements, walls and roofs may be
considered simultaneously, but not in combination with overall
structure loads.
6. Local wall and roof pressures shall not be used when computing entire
bent, structural frame, or moment stability of structure.
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
"tJ
)! ::u
-I
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I
Ul
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()
-i c
~
0
(11
Ul
G)
z
()
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===i
(11
:0
2.25 -Cl .._,
ns
(/) 1.88
a
~1.50
ffi
...J
~ 1.13
~
<1. 0.75
0:
i-w f}; 0.38
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A
I I, . .I
RESPONSE SPECTRUM
~~f\1 FOR MODIFIED ACCELEROGRAM
REF: WOODWARD·CLYDE CONSULT
REPORT• ''DESIGN EARTHQUAKE STUDY'
NOV 10 1 1981
' I
~ MEAN RESPONSE SPECTRUM FOR MAXIMUM EARTHQUAKE
L_ BRADLEY LAKE HYDROELECTRIC PROJECT ·
II.. (NEARBY SHALLOW CRUSTAL FAULT)
~ I~ ~ l MEAN RESPONSE SPECTRUM
~ '\ "'----FOR DBE
--:--.... ~ ~ --..;;: -~ --I ~
0.00 o.oo 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00
PERIOD (SEC)
MODIFIED ACCE:l...EROGRAM
NORMALIZED TO 0.75g-5°/o DAMPING FOR MCE
MEAN · RESPONSE SPECTRA FOR MCE & DBE
. (LINEAR SCAl-E PLOT)
~~--------------------------------------------------------------------~------~
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-t c
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r
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rt1
::0 -)>
2.5
-Ol
....... C112.0
l/) 1.88
z
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~ ~ 1.5
~ w
~
_J 1.0
~ .88
tJ .75
lU a..
l/) Q.5
. 35
0
0.01
I
!
I
-i
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/
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v /
0.03
! I' I I I
' . DAMPING • 5 °/o.
\MCE
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\ v 1\ v . ' v 1\ I i
' N v.-NEARBY SHALLOW
. \DBE
rtiM CRUSTAL FAUL.T
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\ \
~/"" """ ' ~ ~ \
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~ ...... "' CRUSTAL FAULT ...I ~ .... ~ "' ~ r--.. !""-... r--r-oo
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PERIOD (SEC)
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MEAN RESPONSE SPECTRA .FOR MCE & D8E
. (SEMI-LOG SCALE PLOT.)
. ..
I
I .
10
L---------------------------------------~----------------~--------~
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
STRUCTURAL DESIGN CRITERIA
PART B: SPECIAL REQUIREMENTS AND DESIGN CRITERIA
FOR MAJOR STRUCTURES
MAIN DAM DIVERSION
MAIN DAM
SPILLWAY
POWER TUNNEL LINING, INTAKE, AND GATE SHAFT
PENSTOCK
POWERHOUSE
TAILRACE
SUBSTATION
4002R/0168R/CM GENERAL STRUCTURAL DESIGN CRITERIA
4029R/CG
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .o. 15800
POWERHOUSE
STRUCTURAL DESIGN CRITERIA
PART B, SECTION 6.0
REVISION: 1
DATE: May 16, 1988
STONE & WEBSTER ENGINEERING CORPORATION
ANCHORAGE, ALASKA
-POWERHOUSE STRUCTURAL DESIGN CRITERIA
SECTION
6.1
6.2
6.2.1
6.2.2
6.2.3
6.2.3.1
6.2.3.2
6.2.3.3
6.2.3.4
6.2.3.5
6.2.3.6
6.2.3.7
6.3
6.3.1
6.3.2
4029R/CG
PART B-6
POWERHOUSE
STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
TITLE
FUNCTIONAL DESCRIPTION
SUPPLEMENTAL DESIGN CRITERIA
General
Materials
Loadings
General
Special Loads
Seismic Loads
Seismic Forces on Elements
Seismic Forces on Systems
Tsunami Forces
Tidal and Hydrostatic Forces
ENGINEERING/DESIGN CONSIDERATIONS
General
Substructure
1. Design
2. Substructure Stability
3. Wall and Slab Design
4. Blackouts
5. Unit 3 Tie-in
6. Spiral Casing
7. Spherical Valve
8. Generator Support Barrel
9. Rotor Erection Pedestal
PAGE
B-6-1
B-6-2
B-6-2
B-6-2
B-6-4
B-6-4
B-6_.4
B-6-4
B-6-5
B-6-7
B-6-10
B-6-10
B-6-10
B-6-10
B-6-12
B-6-12
B-6-13
B-6-13
B-6-14
B-6-14
B-6-15
B-6-16
B-6-17
B-6-17
POWERHOUSE STRUCTURAL DESIGN CRITERIA
SECTION
6.3.4
6.3.5
6.4
Attachments:
TABLE OF CONTENTS
(Cont'd)
TITLE
Superstructure
1. Framing
2. Temperature Considerations
3. Design and Analysis
4.
5.
6.
7.
8.
9.
Connections
Unit 3 Tie-in
Power Transmission Line
Tailrace Gate
Tailrace Deck and Gate Storage
Crane Girders
Structure Stability
Miscellaneous
1. Floor Finishes
2. Load Rating/Laydown Control
DESIGN GUIDELINES AND REFERENCES
Attachment A -Powerhouse Area Groundwater and Uplift Pressures
Attachment B -Mean Horizontal Response Spectra
Attachment C -Tsunami Wave Forces on the Powerhouse
PAGE
B-6-17
B-6-17
B-6-18
B-6-18
B-6-19
B-6-20
B-6-20
B-6-20
B-6-24
B-6-25
B-6-27
B-6-31
B-6-31
B-6-32
B-6-32
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
PART B-6
POWERHOUSE
STRUCTURAL DESIGN CRITERIA
B-6-1
6.0 POWERHOUSE
6.1 FUNCTIONAL DESCRIPTION
4029R/CG
The Bradley Lake Hydroelectric Project powerhouse will be
designed to house two 45 MW -Pel ton-type turbines with generators
and associated support equipment and systems.
The powerhouse shall be classified a Group B Occupancy, Type II-N -construction in accordance with the Uniform Building Code.
The powerhouse will consist of a reinforced concrete substructure
founded in rock and a structural steel superstructure enclosed
with insulated siding and roof. The structure will be
approximately 80 ft wide by 160 ft long. The substructure will
extend from project El -9 at the discharge chamber level to El
+42 at the generator floor level. The superstructure will extend
from El +42 to approximately El +85.
The substructure will consist of the Generator Floor at El +42,
the Turbine Floor at El
associated with operation
+21, and sumps,
of the turbine
pits and chambers
located at lower
levels. The Turbine Floor, in addition to providing access to
the turbines/generators, will contain the lube oil processing and
storage facilities, the battery room, the emergency diesel
generator and other equipment associated with the plant
operation. The Generator Floor will consist of an open 56 ft
wide bay serving the two generators with control equipment, and
POWERHOUSE STRUCTURAL DESIGN GRITERIA
6.2
6.2.1
6.2.2
4029R/CG
B-6-2
will include a lay down and Service Bay, and a 24 ft wide
Auxiliary Bay housing the control and service needs of the
powerhouse. The Auxiliary Bay will contain support facilities
which will ·include the Control (SCADA) Room, plant office, lunch
room, locker room, toilets and the machine shop. The Generator
Floor will remain clear with access for a 160 ton bridge crane
with an auxiliary 25 ton hook. The bridge crane shall run the
full length of the powerhouse. Hatches will be provided to access
lower levels. The Auxiliary Bay will additionally be designed to
support a secondary floor at El +60 which will house HVAC
equipment and provide room for storage.
The powerhouse substructure and superstructure shall be designed
with the consideration in mind that a third 45 MW unit may be
added to the south side in the future. Excavation of the rock
'
for the third unit's substructure will be accomplished with the
excavation for the first two units to avoid future blasting near
operational units. The excavated area will then be backfilled
until the third unit is installed.
SUPPLEMENTAL DESIGN CRITERIA
General
Part A of this Structural Design Criteria shall serve to identify
all general criteria for buildings and structures, including that
.of the powerhouse, and shall be supplemented by the additional
design criteria contained herein.
Materials
Unless otherwise noted below, materials shall conform to the
requirements of Part A of this Criteria.
POWERHOUSE STRUCTURAL DESIGN CRITERIA
4029R/CG
B-6-3
1. Anchor Bolts
In general, anchor bolts for embedment in concrete shall be ASTM
A307, Grade B materl.al. Where heavier loads warrant, anchor
bolts may be ASTM Al93, Grade B7. Anchor bolt sizes and types of
materials for a particular application shall not be mixed.
2. Stair Treads
Refer to the Architectural Design Criteria.
3. Concrete
Structural concrete shall develop a specified minimum compressive
strength of 4,000 psi in 28 days.
4. Reinforcing Steel
Reinforcing steel above El 21 shall be uncoated rebar.
Reinforcing steel below El 21 which may be exposed to salt water
or brackish water shall be epoxy coated rebar. Rebar which is to
be epoxy coated shall be designated on the drawings.
5. Grout
Grout shall be non-metallic. non-shrink/nonexpansive grout and
will be required to develop a minimum specified compressive
strength of 5,000 psi in 28 days.
6. Bearing Pads ·
Acceptable bearing pad products are:
a.
b.
c.
Fabreeka by Fabreeka Products Co.
Lubrite by Litton Merriman
Fluorogold by Fluorocarbon
POWERHOUSE STRUCTURAL DESIGN GRITERIA
6.2.3
6.2.3.1
6.2.3.2
6.2.3.3
4029R/CG
B-6-4
Loadings
In addition to normal equipment and design loading conditions
imposed on the structure, the effects of seismic induced loads 9
tidal conditions, tsunamis, and hydraulic loads shall be
considered.
General
Refer to the following for general load information:
Table 1, Part A-Selected Material Weights
Table 2, Part A -Floor Loads
Table 3, Part A-Estimated Equipment Weights
Table 4, Part A -Miscellaneous Equipment Loads
Table 5, Part A-Snow Loads
Table 6, 7, and 10, Part A -Wind Loads
Special Loads
Transmission line conductors will be attached to the north wall
of the powerhouse superstructure and will impart loads into the
powerhouse structure. Refer to the Project Lead Electrical
Engineer for applicable loads.
Seismic Loads
The pow,erhouse shall be classified as a "Critical" structure per
Section 4.8, Part A with seismic load application as defined
herein. Seismic design of the steel superstructure shall be as
defined in Section 6.3.3(3)·herein. The primary lateral support
system (diaphragm and shear walls), and its supporting elements,
for the concrete substructure shall be designed for a
pseudostatically applied horizontal acceleration of 0.75g, with
an ultimate design load of U = 0.67 (1.4D + 1.7L + 1.87E) (based
POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-5
on a 50 percent allowable stress. increase for the extreme seismic
event). Secondary structural elements and interior walls shall
be designed for a pseudostatically applied horizontal
acceleration of 0.35g, with material stresses not exceeding
normal design working stresses. Lateral seismic forces shall
include accelerations applied to 25 percent of the floor live
load or alternatively applied to actual equipment weights.
For the construction case (Stage I concrete only), a
pseudostatically applied horizontal acceleration of 0 .lOg shall
be considered, at normal design working stresses, and neglecting
vertical acceleration.
Vertical seismic loading shall be taken as 2/3 of the horizontal
acceleration and shall be considered independent of the
.horizontal acceleration, except as otherwise stated.
6.2.3.4 Seismic Forces on Elements
4029R/CG
Parts or portions of structures and nonstructural components such
as architectural items, and their anchorage to the main I"
structural system, shall be designed for lateral forces in
accordance with the following formula:
Where: F p
A v
c c
h n
Fp = Av Cc (1.0 + ~Wp
hn
= Lateral force on a part of the powerhouse
and in the direction under consideration.
= Seismic acceleration coefficient.
= Numerical seismic horizontal coefficient
(dimensionless) as specified in Table B6-4.
= Height above the base (El 42) to level n
where n is the top level of the building.
POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-6
hx = Height above the base (El 42) to level x
where x is the level of the object.
Wp = Weight of system or component
NOTE: hx/hn shall be taken as zero below El 42
(Forces are based on ATC 3-06 with
modifications)
A one third increase in allowable stresses shall be permitted for
the above seismic forces on elements.
Table B6-4
Seismic Coefficient Cc and Assigned Av
Required for Architectural Systems or Components
Description of System or Component
Appendages
Exterior Nonbearing Walls
Wall Attachments
Roofing Units
Free Standing Containers and
Miscellaneous Components
Partitions
Stairs and Shafts
Horizontal Exits Including Ceilings
Corridors
Full-Height Other Partitions
Partial-Height Partitions
Structural Fireproofing
-Non Fire Rated Membrane
Architectural Equipment and Accessories
Ceiling, Wall,.or Floor Mounted
0.9 0.35
3.0 0.35
0.6 0.35
1.5 0.35
1.5 0.35
0.9 0.35
0.9 0.35
0.9 0.35
0.6 0.35
0.9 0.35
0.6 0.35
0.9 0.35
..
-
6.2.3.5
4029R/CG
B-6-7
Seismic Forces on Systems
1. Cable Tray Systems
In general, cable tray systems shall be designed in accordance
with Structural Technical Guideline STG 19.5-0, "Seismic Category
I Cable Tray Systems". The peak acceleration to be used in
design shall be l.Og for cable trays at or below El 42. The peak
acceleration for cable trays above El 42 shall be based on the
Project Design Response Spectra for a mean horizontal ground
acceleration of 0.35g.
Alternately, where a cable tray system does not fall within the
limitations of STG 19.5-0, the cable tray system may be designed
pseudostatically with vertical acceleration considered simulta-
neously with horizontal acceleration in any one direction.
Allowable stresses may be increased by one-third.
2. Conduit Support Systems
Where seismic analysis is required, runs of conduit not supported
in or part of a cable tray ~ystem may be designed by either~ of.
the following methods:
a. Structural Technical Guideline STG 19.4-0, Seismic
Design of Conduit Systems. Acceleration based on
Project Design Response Spectra for a mean horizontal
ground acceleration of 0.35g.
b. Pseudostatic
acceleration.
design using a l.Og horizontal
However, seismic design will not be required for electrical
. conduit less than 2-1/2 in. inside diameter.
Allowable stresses may be increased by one-third.
POWERHOUSE STRUCTURAL DESIGN CRITERIA
4029R/CG
B-6-8
3. Pipe Support Systems
Seismic design of pipe support systems, where required, shall be
based on either of the following:
a. Design using Project Design Response Spectra for a mean
horizontal ground acceleration of 0.3Sg, with a
one-third increase in allowable stresses.
b. Pseudostatic design using a l.Og horizontal
acceleration, with a one-third increase in allowable
stresses.
Seismic design of supports for fire protection piping systems
shall be based on The Project Design Response Spectra for a mean
horizontal ground acceleration of 0. 75g, with a one-third
increase in allowable stresses.
Seismic design will not be required for the following
installations:
a. Piping less than 1 1/4 in. inside diameter in
mechanical rooms.
b. All other piping less than 2 1/2 in. inside diameter.
c. All pipe suspended by individual hangers 12 inches or
less in length from top of pipe to bottom of the
support for the hanger.
4. Duct Support Systems
Seismic design of duct support systems, where required, shall be
based on either of the following:
a. Design using Project Design Response Spectra for a mean
horizontal ground acceleration of 0.35g, with a
one-third increase in allowable stresses.
POWERHOUSE STRUCTURAL DESIGN CRITERIA
4029R/CG
b.
B-6-9
Pseudostatic design using a l.Og horizontal
acceleration, with a one-third increase in allowable
stresses.
As a minimum, ductwork shall be supported by hangers on either
side of a joint. However, seismic design will not be required·
where ducts are suspended by hangers 12 inches or less in length
from the top of the duct to the bottom of the support for the
hanger, or where cross-sectional area is less than six square
feet for rectangular ducts.
5. Anchorage of Equipment
Anchorage of mechanical and electrical equipment will generally
be designed by the Contractor. Equipment shall be identified as
to its design seismic requirements, with the following general
design levels:
a. Non-critical equipment: Anchorage and support shall be
designed to withstand the following pseudostatically
applied ac.celerations, applied simultaneously:
b.
Horizontal acceleration = 0.88g
Vertical acceleration = 0.59g
Critical equipment: Unless otherwise specified,
anchorage and support shall be designed to withstand
the following pseudostatically applied accelerations,
applied simultaneously:
Horizontal acceleration= 1.88g
Vertical acceleration = 1.2Sg
Local structural support for equipment shall be evaluated for the
above anchorage forces, except that horizontal and vertical
acceleration may be evaluated independently.
POWERHOUSE STRUCTURAL DESIGN QRITE~IA
6.2.3.6
6.2.3.7
B-6-10
Tsunami Forces
Tsunami forces shall be considered for the west wall of the
powerhouse-and its support elements~ only. The design forces
shall be in accordance with Attachment C, Tsunami Wave Forces on
the Powerhouse (IOM dated July 17, 1987). Basic allowable
stresses may be increased by one-third (or corresponding
reduction in load factors) for this condition.
Tidal and Hydrostatic Forces
The powerhouse substructure will be subject to hydrostatic
forces, hydraulic uplift forces due to high ground water table,
and-tidal fluctuations. Hydrostatic pressures shall be applied--
as described in Attachment A, using perforated walls and slabs at
the discharge chamber.
6.3 ENGINEERING/DESIGN CONSIDERATIONS
6.3.1 General
The areas ·that follow require special attention during design. They
have been divided into areas concerned with the substructure, the
superstructure, structure stability, and miscellaneous items.
Where equipment has been purchased and vendor drawings are available
prior to design completion, such as for the turbine-generator
equipment, the structural design shall be based on the loads provided
by the equipment supplier. Where designs are substantially based on
reference equipment which has not been purchased, such as for the
powerhouse bridge crane and for the substation transformers, the
applicable design loads and weights shall be designated on the
drawings and the design calculations shall be identified by marking
the "Confirmation Required" column provided on the calculation title
page, with the items requiring confirmation identified in the
calculation. Where equipment loads are expected to be minor such that
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
they will not significantly impact the structural design, the
structural elements shall be designed in accordance with the criteria
described herein, and equipment anchorages designed by the Contractor
shall be-reviewed when submitted as part of the Contractor submittals.
The powerhouse excavation and installation of all rock anchors/dowels
embedded into rock will be performed by the General Civil Construction
Contractor. The Powerhouse Construction Contractor will be
responsible for construction of the powerhouse concrete and steel
structures and installation of
equipment supplied by others.
be removed by the General
the powerhouse equipment, including
The tailrace dewatering cofferdam will
Civil Construction Contractor after
completion of construction of the powerhouse primary concrete
(Stage I) and superstructure, and installation of the tailrace gates.
The powerhouse structure shall be designed allowing fqr concrete
construction to be completed in two stages.
concrete will be constructed as "Stage I
The primary structural
concrete" allowing for
superstructure· and bridge completion of installation of the steel
crane prior to initiation of Stage II concreting. "Stage II concrete"
is that concrete surrounding the primary embedded equipment for the
turbine-generators, including the spiral casing encasement concrete
and the generator support barrel.
The powerhouse construction shall be detailed to permit expansion of
the structure to accommodate a future third unit to the south. The
steel superstructure shall be developed to permit continuation of the
crane rails and girders for the crane to have clear access to the
third unit. In as much as is possible, the powerhouse design and
third unit conceptual design shall be developed to isolate the two
structures to minimize load transfer between the two structures.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-12
6.3.2 Substructure
1. Design
The concrete substructure shall be statically designed for the loads,
forces and conditions identified in Part A and herein. The
substructure shall be treated as a rigid base in sufficient contact
with the foundation rock to be considered to move with the rock when
experiencing motion due to earthquake. In order to assure that this
does occur, the concrete walls and base slabs will be placed against
·clean rock faces wherever design permits, to develop mechanical
interlock between rock and concrete. Rock anchors may be required to
assure that full contact or adequate rigidity is attained and-to
assure that the substructure meets the stability requirements for the
powerhouse structure. Guidelines and criteria for the size, capacity,
use, and placement of rock anchors will be developed in conjunction
with the Geotechnical Design Criteria.
The substructure's elements shall be designed to be of sufficient
rigidity to resist lateral loads. Use of walls as shear walls and
slabs as diaphragms shall be considered.
Concrete elements shall be designed and detailed with seismic activity
in mind. The primary lateral support system for the substructure
shall be detailed in accordance with the requirements of ACI 318-83,
Appendix A. Reinforced columns or beams shall be detailed so as to
contain and restrict the core to provide reserve strength and
flexibility during a seismic event and to prevent sudden failure of
the core. (Refer to SEAOC 1980 and SEAOC 1985 Interim Report for
detailing considerations.)
4029R/CG POWERHOUSE STRUCTURAL DESIG~ CRITERIA
B-6-13
Concrete for the powerhouse structure will be 1n contact with both
fresh and salt water either from runoff, drainage of the cut rock
faces, or by tidal and wave action.
-Concrete protection for reinforcement shall meet the minimum
requirements of ACI 318-83, Section 7. 7, and shall be in accordance
with Part A, Section SA of the Structural Design Criteria. Epoxy
coated rebar shall be used at all faces exposed to water below El 21.
Splices and basic development lengths shall be increased for all epoxy
coated rebar as follows:
Flexural tension splice lengths in beams, colurnrns, and slabs and
critical tension splices for seismic stability shall be increased
by a factor 1. 50, unless clear concrete cover is greater than
3db and clear spacing of bars is greater than 6db or unless
the splice is confined by special transverse reinforcement.
All other development lengths for epoxy coated bars shall be
increased by a factor of 1.15.
The net combined factor, including the factor for top bars, need
not exceed 1.50.
2. Substructure Stability
Refer to Section 6.3.4 which covers full stability analysis
requirements for the powerhouse.
3. Wall and Slab Design
High water table in the excavated rock and subsequent seepage adjacent
to the powerhouse wall will cause a build up in pressures against the
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-14
walls and under the powerhouse slabs. Tidal fluctuations will also
cause flooding of the surrounding rock foundations. The east wall of
the powerhouse which is in contact with rock shall be fully drained
from El 18 to El 39 to eliminate hydrostatic pressure using a
perimeter drain system designed to drain to the tailrace.
Walls of the discharge chambers cast against rock below El 18 shall be
provided with weep holes to reduce hydrostatic pressures. The
discharge chamber slab shall also have weep holes.
Type of drain material, and size, position, and spacing of weep holes
shall be determined by the Project Geotechnical Group. Slabs may be
required to be anchored by dowels to the rock against nominal uplift
pressure.
4. Blackouts
Blackouts shall be provided at specific locations for: (1) adequate
alignment room for such items as gate guides, sill beams, wall
penetrations, etc., (2) construction sequencing purposes,, and (3)
major equipment which requires concrete embedment. As a minimum,
blackouts shall be provided for the following:
a. Turbine
b. Generator
c. Penstock penetrations at east wall
d. Tailrace gate guides, sill beams and invert seal
beams
5. Unit 3 Tie-in
The substructure for Units 1 and 2 shall be separate from and
independent of that for the future third unit. A knockout panel shall
be provided in the south wall located at the main corridor to provide
access continuity between the two substructures at El 21. The wall
panel shall be designed for backfill as shown on the final grading
plans.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-15
6. Spiral Casing
The turbine spiral casing (also called · the spiral distributor or .
turbine manifold) shall be enclosed in reinforced concrete. The·
manifold will be pressurized to 100 percent of static head during
concreting. The surrounding concrete shall be designed to withstand
the strains developed due to the difference between the design
pressure and 100 percent of static head. For design pressures to be
used refer to the Hydraulic Turbines,· Governors, and Spherical Valves
Performance Criteria issued by the Project Lead Hydraulic Engineer.
The spiral case will be designed for several levels of pressure, with
allowable stress conditions as follows:
Pressure Level Allowable Working Stress
Normal Allowable Stress~·,
Normal Allowable Stress~·,
1.
2.
3.
4.
5.
Normal static head
Design head
Test head
Emergency head·
20% Allowable Stress Increase
SO% Allowable Stress Increase
Extreme emergency head Yield Stress
Use O.SOFy basic allowable stress for rebar
The spiral casing will be fabricated from steel plate material similar
to ASTM A516. The casing will be designed to carry unwinding forces
and internal pressure forces by itself without reliance on surrounding
concrete. Concrete will provide damping action against vibrational
forces and supplementary support against net thrust forces.
The spiral casing will be seated on concrete pedestals during
construction. Bolt down information, physical position, orientation,
and elevations will be provided by the turbine manufacturer.
A first stage concrete slab will be provided for spiral casing
support' followed by staged pours after setting the spiral casing and
turbine chamber pit liner in place.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-16
7. Spherical Valve
The spherical valve complete with servomotor will be located between
the penstock and the turbine, placed in a gallery with floor at El · 5.
The valve will be seated on a concrete pedestal with a sliding base
plate assembly.
The base plate assembly will be designed to permit longitudinal
movement along the centerline of the pipe up to one inch, but will
restrict .vertical and lateral movement. A low friction bearing
material will be incorporated into the assembly to allow the unit to
slide. The full valve assembly will be provided and detailed by the
valve manufacturer. The servomotor, its base, and its anchor bolts
and the tie rod assembly will also be provided by the valve
manufacturer.
The pedestals for the spherical valve and servomotor shall be designed
to accommodate all applied forces identified by the valve
manufacturer. The pedestal shall be designed for stability
considerations and for forces imposed by penstock movement, including
torsion, friction and forces from the servomotor and tie rod.
The spherical valve shall be considered a critical piece of
equipment. The support pedestal shall be designed for a horizontal
seismic ground acceleration of 0.75g (as identified in Part A, Section
4.8.2-B) and a simultaneous vertical ground acceleration of o.sog.
Valve operation shall be considered simultaneously with a horizontal
seismic ground acceleration of 0.35g and simultaneous vertical ground
acceleration of 0.23g.
The following load factors shall be used for design of the concrete:
4029R/CG
Design Condition
Valve Static Condition
Valve Operation
Valve Operation with
Design Basis Earthquake (0.35g)
Maximum Credible Earthquake (0.75g)
Concrete Load Factors
1.4D
1. 4D +1. 7L
0.67 (1.4D + 1.7L +1.87E)
0.67 (1.4D + 1.87E)
POWERHOUSE STRUCTURAL DESIGN CRITERIA
6.3.3
B-6-17
8. Generator Barrel
The generator support barrel shall be constructed of reinforced_
concrete and shall be designed for the generator loads as specified by
the generator manufacturer. For unusual loads, such as the short
circuit load, a one third increase in allowable stresses may be
permitted (or equivalent reduction in ultimate load factors). The
generator barrel shall be designed to carry the vertical load from the
El 42 floor slab, but shall be designed to minimize horizontal load
transfer between the slab and the barrel.
9. Rotor Erection Pedestal
The ·generator rotor will be erected in the Service Bay of the
powerhouse at El 42. The rotor support details will be provided by
the equipment manufacturer.
The rotor support shall be designed to be stable, when loaded, during
a seismic event of O.lg horizontal acceleration and with a factor of
safety against overturning of F.S. = 1.5.
Superstructure
1. Framing
The superstructure will be a steel framed structure constructed of
ASTM A36 hot ·rolled structural steel plates and shapes, wherever
possible. The powerhouse superstructure will be enclosed with metal
siding and covered by a metal standing seam roof. The building will
be insulated and will be heated and ventilated.
Interior design temperatures and minimum insulation requirements are
to be found in the Architectural Design Criteria.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-18
2. Temperature Considerations
During construction, and before full enclosure of the powerhouse and
heating; it is anticipated that the surface temperature of the
structural steel framing may vary by a temperature range of ~T =
80°F. Stresses induced in the structure's framing due to temperature
changes in the steel shall be evaluated in design. When in operation,
temperatures may be considered to remain at an even, controlled
working level.
3. Design and Analysis
The powerhouse superstructure shall be designed as having .pin
connected· elements, unless otherwise directed by the Project Lead
. Structural Engineer. As a minimum, the following design cases shall
be considered:
Case 1 Static design
Case 2 Static design including wind effects
Case 3 Static design including seismic effects
Case 4 Dynamic analysis considering seismic effects
Case 5 Temperature Conditions
Design of each bent shall consider the bridge crane loading. For
overall seismic analysis of the structure using dynamic analysis, the
crane shall be considered to be parked next to the southernmost bent
over the Service Bay.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-19
The seismic design of the steel superstructure will consider the
ductility and repairability of the steel framework and, as such, shall
be designed for a mean horizontal ground acceleration of· 0.35g with
material stresses not exceeding normal ·design working stresses. A-
static lateral force coefficient of 0.35g shall be considered with the
bridge crane in any location. A response spectrum dynamic analysis
shall be performed in accordance with the Project Design Response
Spectrum for a 0.35g mean horizontal ground acceleration, provided as
Attachment B, with the bridge crane in its parked position. All steel
connections (including base plates) and supporting concrete shall be
designed for the reactions obtained from the above analyses, with the
seismic component multiplied by a factor of 2.14 (Q.75g divided by
0. 35g) to provide adequate reserve strength in the connections ·and
substructu-re to meet the Maximum Credible Earthquake; for -this
condition a 50 percent increase in allowable stress (or appropriate
·load factor) will be permitted.
The steel superstructure shall be similarly designed for a vertical
seismic loading using 2/3 of the horizontal ground acceleration.
Vertical and horizontal seismic loadings shall riot be combined and
will be considered to·act independently for this criteria.
Cases considering seismic effects shall include, as independent cases,
the following:
a. Horizontal. seismic loading applied separately about each of
the principle axes of the structure.
b. Vertical seismic loading (acceleration either up or down)
based on 2/3 the horizontal ground acceleration.
4. Connections
Connections shall be bearing type connections, unless reversible
forces occur, where friction-type connections shall be used. Unless
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-20
otherwise directed by the Project Lead Structural Engineer, the
structural steel design for friction-type shear connections will be
predicated on Class E, blast-cleaned, organic zinc rich paint surface
condition of bolted parts, using standard bolts. This results in an
allowable working stress of 21.0 ksi for A325 bolts and 26.0 ksi for
A490 bolts.
Whenever possible 7/8 in. diameter ASTM A325 bolts shall be used,
except that 3/4 in. diameter ASTM A307 bolts may be used for stair
treads, and 1 in. diameter ASTM A490 bolts may be used for heavy
connections. Bolt diameters and types shall not be mixed.
5. Unit 3 Tie-in
The superstructure's end bent on the south side shall be designed to
be eventually tied into a third unit. Should a third unit be
constructed in the future, the end wall bracing (except bracing
between column lines D and E), wind columns, girts, and siding will
be removed and relocated to the southern end of Unit 3. A new bent on
new foundations would be located alongside the south bent for the
first bay of the third unit.~
Bent, crane girder, framing, and bracing shall be designed and
detailed to carry loads appropriate to this future arrangement.
6. Power Transmission Line
The power transmission line will use the north wall of the powerhouse
as a take-off structure. As such, point loads will be applied to the
framing as a result of conductor tension and wind and ice loading.
Refer to the Project Lead Electrical Engineer for applicable loads.
7. Tailrace Gate
The tailrace gates are used to close off the discharge chambers of the
powerhouse to provide a dewatered condition for access to the turbine
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-21
and the turbine runners for purposes of inspection, servicing, and
repair, and will be used during construction to maintain a dewatered
condition during Stage II concreting. Subsequent to construction, the
gates will be in place only on a limited basis, estimated to be a
maximum of 10 days per year. One gate will be provided for each unit.
The gates shall be constructed of a structural steel frame covered by
a skin plate on one side. The skin plate shall be located on the
downstream side of the gate (tailrace side).
The tailrace gates are to be analyzed assuming that the hydrostatic
pressure applied to the gate skin will act across a gate frame with
horizontal intermediate support beams supported by vertical end
columns. The skin pl_ate will span continuously over the horizontal
beams.
The gates shall be designed for installation ·and removal under a
balanced head condition. A compression seal shall be provided as a
bottom seal. J-seals shall be provided on sides and on the top.
The gate skin plate shall be welded to the support beam framework and
will therefore act to some extent with the beams by performing as part
of the beam flange. Biaxial stresses shall be considered, as well as
bending, as part of the beam design considering the following
relationship.
where
f = f uf combined x y
f = flexural stress (in :X, y direction)
u = Poisson's ratio
The top beam and side columns of the gate frame shall be designed to
assure that the webs of these members can withstand the hydrostatic
loading combined with bending moments induced by the flexing of the
attached skin plate.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-22
The tailrace gates· shall be provided with seals, springs, and bearing
blocks. Springs shall be provided to preload the seals prior to
developing hydrostatic loads. Bearing blocks shall be provided to
prevent excessive deformation of the seals.
The tailrace gates are considered "non-critical" structures and shall
be designed for a pseudostatically applied seismic acceleration of
0.35g. Since the gates will be installed on a limited basis, it is not
considered necessary to design the structures for the extreme basis
earthquake or tsunami.
The following minimum load combinations shall be investigated:
4029R/CG
Case 1 Hydrostatic at maximum storm surge (El +14)
Case 2 Hrdrostatic at maximum
Case 1, with 5 ft waves.
stresses will be allowed.
storm surge as in
A 1/3 increase in
Waves are assumed to
not be breaking with developed pressure. Value
of pressure will be based on the following
formula from Standard Handbook for Civil
Engineers by F.S. Merrit (McGraw-Hill, 1976):
P=~d + ~H
COSH (2 'II' D/L)
where:
p = pressure
( = specific weight of sea water
d = depth under consideration
H = wave height (5 ft)
D = total depth of water
L = wave length (assume 50 ft)
POWERHOUSE STRUCTURAL DESIGN CRITERIA
Case 3 Hydrostatic at maximum storm surge
(conservatively-Case 1) with a 0.35g seismic
acceleration applied, allowing a 1/3 increase
in stresses
B-6-23
Case 4 Ice loading of 2 kips per ft -shall be considered
to act at any location across the £ace of a gate as
a 1 ft deep layer of ice. As tide varies it is
assumed that ice will break up and layering and
build up will not occur. This is considered a short
term loading. Stresses will be allowed a 1/3
increase.
The tailrace gates shall be fabricated of ASTM A36 hot rolled
structural shapes and plate material. Plate shall be a minimum 3/8
in. thick. A corrosion allowance of 1/16 in. shall be used for the
skin plate design.
Spring steel shall be ASTM A564 Type 630, heat treatment Hl025 with
the following properties:
Ultimate stress (F ) u
Yield stress (F ) y
Brinnel Hardness
155,000 psi
145,000 psi
331
For configuration and type of seals refer to the Project Lead
Hydraulic Engineer.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-24
8. Tailrace Deck and Gate Storage
The tailrace deck is located on the west side of the powerhouse at El
21. The deck provides access to the tailrace for installation and
removal of the tailrace gates. The gates, when not in use, are to be
vertically seated and stored on the tailrace deck. The deck is
provided with an open grating to facilitate shedding of snow, rain
water, and ice. Local gate slots will be provided and protected by
removable handrail. A monorail will be located above the tailrace
deck, positioned to be able to place, remove, and store the tailrace
gates by use of two 7 1/2 ton hoists. The gate hoists will be trolley
mounted and will be interconnected by a tie bar. One trolley will be
motorized with a pendant operator and shall be provided with a hand
'
chain. The full criteria for the hoists will be provided by. the
Project Lead Power Engineer. The tailrace hoist system will be
located just below the El 42 level. (The designer should pay
particular attention to clearances for gate handling.)
The tailrace gates will be inserted infrequently (refer to Section
6.3.3(7), Tailrace Gates, herein). The gates will be stored on the
deck adjacent to the covered gate slots in the deck, and will be
battened down against the wall. When installed, a gate will remain
hung from the hoist rig, unless a second gate needs to be installed.
The gate will generally remain attached to the cable, with no load
applied to the hoists since the gate will rest on the gate guide sill.
To assure that the gates are properly fastened to the wall when in a
stored vertical position, the storage brackets shall be designed for
0.35g horizontal earthquake acceleration.
Loads:
a. Dead Load (D)
1. Deck = 25 psf
ii. Gate ·storage = 700 plf
b. Deck Live Load (L) = 150 psf
c. Deck Snow Load (S) = 110 psf
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
d. Seismic (E)
i. Concrete elements
H = 0.75g
V = 0.50g
B-6-25
ii. Steel platform and support bracket:
e. Wind
H = 0.35g
V = 0.25g
Refer to Structural Design Criteria, Part A
Load Combinations:
Case 1 D+L
Case 2 D+S
Case 3
Case 4
Case 5
D+L+E
D+O.SOS+E
D+L+W
(Seismic applied only to dead load)
Horizontal and vertical seismic accelerations will be considered to
act separately. Allow 1/3 stress increase on materials loaded under
seismic or wind conditions except as noted. No increase in stress is
allowed for brackets and connections of members for the seismic
condition.
9. Crane Girders
The powerhouse crane will be a 160 ton bridge crane with a 25 ton
auxiliary hook. The crane will be provided with a cab and a pendant
operator. The powerhouse crane will be installed once the
superstructure is in place and will be· rigged and electrified to be
used during installation of major equipment such as the turbine and
generator parts. While not in operation; the crane will be parked next
to the south end wall of the powerhouse. Access to the cab will also
be provided in this location.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-26
The design and detailing of the crane girders shall be developed to
consider future extension of the girders into the third unit to the
south. For this purpose the ends of the crane girders shall be
detailed for interfacing with the future crane girders. Load analysis.
shall account for effects of continuation into the third unit.
Crane stops shall be provided at each end of the powerhouse to prevent
the crane from damaging the framing, high voltage bus duct, and siding
should the crane fail to stop or should the crane shift due to seismic
activity. Stops for each girder shall be designed to take the full
crane impact load imposed by the crane bumper based on four percent of
rated crane speed.
Seismic restraints shall be provided as part of the bridge crane
assembly. These restraints shall be designed to prevent the crane
from moving off of the crane girders during a seismic event, based on
the loads developed in the dynamic analysis of the superstructure.
The crane girders shall be supported on columns separate from the main
building columns. The crane support columns shall be laterally braced
to the main columns and longitudinally braced to each other. The
crane girder shall be designed as simply supported between columns.
Crane rails shall be a minimum 171 pound rails and shall be sized and
detailed in accordance with the requirements for adequate restraint
and fixity for anticipated lateral and longitudinal loads. Crane rail
size shall be verified with the Project Lead Power Engineer.
Design loads shall conform to the information of Part A, Section 4.16,
Crane Impact Allowance and Table 4, Miscellaneous Equipment Loads.
The wheel spacings, crane clearances, and movement of the trolley and
its load shall be provided by the Project Lead Power Engineer.
Deflection of the crane girder shall follow Part A, Section 5.3. A
crane load diagram shall be provided on the crane girder drawings and
the maximum weight of crane used in design shall be noted on the
design drawings (refer to Part A, Table 3).
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-27
The effects of the weight of the unloaded crane .on the seismic design
of the powerhouse superstructure shall be analyzed as given in Section
6.3.3 (3) herein.
The following load ·cases as a minimum shall. be considered in the
des.ign of the crane girder and the support structure.
Case 1
Case 2
Case 3
Case 4
D + D (crane) + Lifted load + Impact c '
. -Jc D + D (crane) + Lifted load + Lateral Load * c longitudinal or transverse
D + D + E (vertical or horizontal) c
Case 1 + 1/2 wind load -used when erected
crane is operated without building being
.enclosed, during construction. Allow a 1/3
increase in stresses. Verify that this condition
will exist with the project Construction
Specialist and Lead Structural Engineer before
analyzing.
6.3.4 Structure Stability
The powerhouse shall be analyzed for stability. Each load case to be
examined shall be classified, based on its probability of occurrence,
as normal, unusual, or extreme. The effects of . the various tide
levels on the horizontal and vertical fluid pressures against the
powerhouse substructure shall be considered. These pressures are
identified as Attachment A to the Powerhouse Criteria, and are an
excerpt from Geotechnical calculations. The structure shall be
analyzed for the load cases identified in Table B6-7. Minimum
required factors of safety shall be as given in Table B6-8.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-28
Two independent structural systems will be considered for evaluation
of structure stability:
1. An independent stability analysis sh&ll be performed for the
powerhouse concrete core, including the generator support
barrels, spiral casing encasements, and discharge chambers.
Vertical loads from the steel superstructure shall be included
where appropriate.
2. Structural design of the El 42 diaphragm and north and south end
shear walls shall be considered to resist all lateral forces from
the steel superstructure and El 42 slab, as well as applicable
vertical loads. Rock anchors may be provided to stabilize the
shear walls.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-29
Table B6-7
STABILITY LOAD CASES AND F.S. CLASSIFICATION
CASE No. CLASS CASE NAME LOADING COMBINATION
1
2
3
4
5
6
7
8
9
4029R/CG
Normal Operating
Unusual .35g seismic
Unusual Storm tide
Unusual Servicing
Unusual Construction
Extreme .75g seismic
Extreme Sump empty
Extreme Construction
with seismic
Extreme 0.50g Vertical
Seismic
-Substructure·, superstructure, and
installed equipment weights
-Running or standby turbine
operating forces
Tide at MHW El +4.0'
Horizontal and uplift fluid pressure
Fluid at El +4.0' in the
discharge chamber
Fluid at El +11.5' in the clean
water sump
-Same as operating case except:
- A 0.35g seismic event (horizontal)
-Same as operating case except:
-Tide at Storm tide El +13.4'
-Fluid at El +5.0' in the
discharge chamber
-Same as operating case except:
-No operating turbine forces
(spherical valve closed)
-Tide at Highest tide El +11.4'
-No fluid in discharge chamber
-Stage I concrete weight only
-Tide at Highest tide El +11.4'
-Horizontal and uplift fluid pressures
-No tailwater pressure
-No fluid in discharge chamber
-No fluid in clean water sump
Same as operating case except:
-A 0.75 seismic event (horizontal)
-Same as operating case except:
-Tide at Highest tide El +11.4'
-No fluid in clean water sump
-Same as construction case except:
- A O.lOg seismic event (horizontal)
-Same as operating case except:
- A 0.50g vertical seismic event
POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-30
Table BG-8
STABILITY FACTORS OF SAFETY AND OTHER PARAMETERS
AS A FUNCTION OF CLASSIFICATION
CLASSIFICATION
NORMAL UNUSUAL EXTREME
F.S. Floatation 1.5 1.2 1.05
F.S. Overturning 1.5 1.2 1.05
F.S. Sliding 3.0 1.5 1.05
Tension allowed 0.0 20 20
before cracking psi psi psi
The assessment of the stability conditions is based on the following
assumptions:
1. Water weight present in the discharge chamber will be included as
a vertical force and will contribute to the resisting moment
against overturning, but will not contribute to the lateral
seismic overturning force.
2. That if the tide water level is at MHW or lower and the turbines
are in operation, then the discharge chamber water level will be
assumed to be at El +4.0. The possibility that the discharge
chamber water level may go lower than El +4.0 during tu~bine
operation has been determined not likely to occur.
3. That if the tide water-level is higher ~han MHW and the turbines
are in operation, then the discharge chamber water level ~ill ·be
assumed to be at El +5.0 due to the effects of the air depression
system.
4. To assume for some cases, as noted, that the water in the clean
water sump wiil be included as contributing to the vertical dead
weight, the resisting moment, and the seismic overturning.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-31
5. The foundation base will be allowed to "crack" in all cases,
providing that all other criteria are met.
6. The factors of safety against sliding shall be computed based
only on the resistance provided by adhesion.
7. Up to 120 psi working adhesion will be allowed for the purposes
of providing sliding resistance. This value has been chosen to
reflect a conservative value which will not require a site
specific rock property test and will not require special
preparation of the excavated surfaces other than surface cleaning
prior to concrete placement.
8. Only areas whe;-e concrete is cast on horizontal surfaces are to
be considered as capable of providing sliding resistance due to
adhesion. No adhesion will be considered for vertical surfaces.
9. If required for sliding stability, the slab areas for slabs at El
-6.0', 3.0', 5.0' and 21.0' can be utilized to provide sliding
resistance.
10. Before an area of a slab can be considered as providing sliding
resistance, the slab will be required to be anchored to the rock
with dowels to prevent de bonding from occurring if the uplift
under the slab exceeds the concrete dead weight.
6.3.5 Miscellaneous
1. Floor Finishes
The Generator Floor, Turbine Floor, and Spherical Valve Gallery shall
be coated with a concrete sealer.
subsequently be applied.
An epoxy coating system will
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-32
2. Load Rating/Laydown Control
Load rat.ing signs shall be specified to be installed adjacent to the
various floors stating load limits, and design 1i ve loads shall be
stated on the design drawings~
In addition, a laydown arrangement will be developed for the Service
Bay locating where various turbine or generator parts are to be laid
down during installation or dismantling for servicing.
6.4 DESIGN GUIDELINES AND REFERENCES
L Light and Heavy Industrial Buildings, AISC 1979, J. M. Fisher, D.
R. Buettner.
2. ATC 3-06, Tentative Provisions for the Development of Seismic
Regulations for Buildings. Applied Technology Council, National
Bureau of Standards. NSF Publication 78-8.
3. SEAOC-80 Recommended Lateral Force Requirements and Commentary.
Structural Engineers Association of California, 1980 Edition.
4. SEAOC-85 -Tentative Lateral Force Requirements, October, 1985.
Seismology Committee, Structural Engineers Association of
California.
5. ACI 318-83 Appendix A, Special Provisions for Seismic Design,
Building Code Requirements for Reinforced Concrete, American
Concrete Institute.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
B-6-33
6. Standard Handbook for Civil Engineers, F. S. Merrit, Mc-Graw
Hill, 1976.
1. Architectural Design Criteria, Bradley Lake Hydroelectric Project.·
8. General Information and Civil Design Criteria, Bradley Lake
Hydroelectric Project.
9. Structural Division Technical Guideline STG 19.4-0, Seismic
Design of Conduit Systems.
10. Structural Division Technical Guideline STG 19.5-0, Seismic
Category I Cable Tray Systems.
4029R/CG POWERHOUSE STRUCTURAL DESIGN CRITERIA
I .
INTEROFFICE MEMORANDUM
1' 0 w8t 1-tv-v~G" 5 TIZ 1/C J1.1'Z ~ 1--")) t:=s-I&N Cr2 I TE)2·, fl
J.O. OR 15800.08 WP 26A
W.O. NO .
• 0~0.26
SUBJECT
DESIGN UATA TRANSMITTAL
BRADLEY LAKE HYDROELECTRIC PROJECT DATE July 20, 1987
FROM Geotechnical Division
TO W. Sherman cc LDuncan
Nl3l::;ho!J
JBK Ml .3
GT UDT Book
I) 1 ease r fnd at L±ched rive ~ages ( 14a-14d, 15) from the revised
geotechnical calculatlor1 15800-G(AK)-027-2, Powerhouse Area Groundwater
and Uplift Pr·essur·es. lnduded is a der·ivatlon of the equations used
to calculate the: exter·naJ hydrostdtic ~r·es::;ur·e on the powerhouse and a
::;urnmo.ry ol' the exter·nal arrd internal pressur·es for· several load
currJ i L iu1r:..;.
A::; we di::;cussed, the::;e ar·e not effective pre::;sures but can be used by
the structur·al division as inputs into powerhouse and slab stability
calculations.
IOTEO J UL 2 0 1987 L~w..a: b
L. C. Duncan
Lead Geotechnical Engineer
2-2119-JJ
~M.j
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CALCULATION SHEET
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W.O. NO.
& 040.2&
SUBJECT TSUNAMI WAVE FORCES ON THE
POWERHOUSE.
_ ____ ___ ___ _ -·-T()---_____ W. C. Sherman
DATE July 17, 1987
FROM
cc
THughes
NABishop
LCDuncan
JTChristian, BOS 245/1D __
YCChang, BOS 245/13
DJurich
JHron
Attached for your use in the design of the powerhouse is a loading
·diagram for pressures and resultant forces associated with tsunami
waves. This diagram supersedes the information contained in the IOC
from the undersigned to you dated October 14, 1986.
The dynamic force resultant, the static pressure, and the static force . __ ---~~~=--~---_i_e13J:iJ!~nt will vary, -depending upon the height of wall which is exposed
---------------tG-Water from the combined tide plus tsunami. The values of the ------------------·
--------------13r-essures and forces·· in the vicinity of the tailrace are given on the------------------~-
·-·---------{!iagl!am·. The terms in the equations which must be changed for -- ---
evalua_tion of the expressions at other points along the powerhouse wall
have been designated.
~ HydraulicJEngineer
-TH/JJ
___ _ __ _ __ Attachment
2-2109-JJ lottd I. A. IISHOP JUL 17 '87
•• ••" _.,.,....,,... .......... .....-.:--~ .. -~ .~,~~ .... AA -• •• • • O•o':.. ·------~ -~-~.--,••o..;:..,,,~.;::~:--''"...,. --,,..,.__ ... _......__,...__.,.,.,..,_ • ., ,, "• .,=...-·;"-~~~~ --·-------
----------------.---------------------------_ .... _ '"""""----~-'"""'---""""----.... _......,..... __ -------
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----Use TOTI\L E)(PDSEO PF\1\T OF
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DAT\11'\ (_eL 2.5' GLP~ fO~
1\\t-:>e "TC: Rr'\ s •
REFERENCE DATUM MLLW OF BEAR COVE ___. _ ___.__;..;.;:.;~..;=.:...;:...;.:::;__::;.:...:..;.~.:......:.....:.=.::.;..:_~--=;..:;:::.:_.;:..;_.=..::;....;...:-_~ ____ ----------------------
GENERALIZED TSUNAMI WAVE
FORCE DIAGRAM
------------------~~---------FIGURE ~5 -----·-·-·-1------------ --.. -.-
4028R/205R/CG
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .0. No. 15800
TAILRACE
STRUCTURAL DESIGN CRITERIA
PART B, SECTION 7.0
REVISION: 2
DATE: March 25, 1988
STONE & WEBSTER ENGINEERING CORPORATION
ANCHORAGE, ALASKA
TAILRACE STRUCTURAL DESIGN CRITERIA
SECTION
7.1
7.2
7.2.1
7.2.2
7.2.3
7.3
7.4
4028R/205R/CG
TITLE
PART B-7
TAILRACE
STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
FUNCTIONAL DESCRIPTION
· SUPPLEMENTAL DESIGN CRITERIA
Materials
Loads
Load Combinations
ENGINEERING/DESIGN CONSIDERATIONS
DESIGN GUIDELINES AND REFERENCES
PAGE
B-7-1
B-7-2
B-7-2
B-7-2
B-7-2
B-7-3
B-7-3
TAILRACE STRUCTURAL DESIGN CRITERIA
7.0 TAILRACE
PART B-7
TAILRACE
STRUCTURAL DESIGN CRITERIA
B-7-1
7 .1 FUNCTIONAL. DESCRIPTION
The tailrace is a pool downstream of the powerhouse designed to collect
water released from the. turbines and to provide a channel to transport that
water away from the powerhouse. The tailrace further acts as a stilling
basin by reducing the turbulent flow of released water before it flows into
Kachemak Bay.
The flow of water from the powerhouse will be channelized and directed into
the main flow path of the tailrace channel by the discharge chamber walls
constructed as part of the powerhouse substructure. No special flow
characteristics or shape requirements are required for the chamber walls.
The walls will be at right angles to the west wall and will be rectangular
in cross section.
The tailrace will be excavated out of the mudflats immediately to the west
of the powerhouse. Rock adjacent to the powerhouse will be removed to
provide proper channel alignment. The sides and bottom of the tailrace
basin will be riprapped for protection from scouring. The tailrace will
presently be sized for two units.
Design of the tailrace channel will be developed as part of the
Geotechnical and Hydraulic Engineering efforts. As part of the Structural
design, a concrete retaining wall will be required to retain the fill
material just north of the powerhouse and west of the substation. The
retaining wall will connect with the north end wall of the powerhouse.
4028R/205R/CG TAILRACE STRUCTURAL DESIGN CRITERIA
B-7-2
7.2 SUPPLEMENTAL DESIGN CRITERIA
7.2.1
7.2.2
7.2.3
Materials
1. Concrete
f'c = 4000 psi at 28 days
2. Reinforcing Steel
Loads
D =
L =
F =
H =
E =
ASTM A615, Grade 60, Epoxy Coated
Dead load (concrete)
Live load or surcharge load, use 300 psf surcharge
Fill load (backfill), use 120 pcf dry weight
Hydrostatic load
Seismic load
Load Combinations
The retaining wall shall consider the following load combinations
and factors of safety.
Load Combination Factor of Safety
1. D + F + H 1.5
2. D + F + H + L + E (O.lOg horizontal) 1.5
3. D + F + H + E (0.35g horizontal) 1.3
4. D + F + H + E (0.23g vertical) 1.3
4028R/205R/CG TAILRACE STRUCTURAL DESIGN CRITERIA
B-7-3
7.3 ENGINEERING/DESIGN CONSIDERATIONS
The tailrace retaining wall shall be designed for backfill loads,
groundwater pressures, surcharge loads due to vehicles, and seismic
loads. The minimum factors of safety against sliding or overturning
shall be in accordance with Section 7 .2.3, herein. The foundation
react.ion shall be within the kern of the base, except for the seismic
condition. Passive pressure against the toe of the retaining wall
shall be neglected. Weep holes (drain holes) shall be provided to
reduce groundwater pressures, however groundwater pressure shall be
assumed at El 11.4 behind the retaining wall, neglecting tailwater
pressure as a resisting force. Lateral soil presures and allowable
bearing pressures shall be in accordance with the Geotechnical Design
Criteria and calculations.
Keyed control joints shall be provided in the retaining wall at a 15
foot maximum spacing to control cracking due to temperature variation.
A guardrail shall be provided at the top of the retaining wall due to
vehicle access at the substation yard.
7.4 DESIGN GUIDELINES AND REFERENCES
1. General Project Information and Civil Design Criteria, Bradley
Lake Hydroelectric Project.
2. Geotechnical Design Criteria, Bradley Lake Hydroelectric Project.
3. Building Code Requirements for Reinforced Concrete, ACI 318-83,
American Concrete Institute.
4028R/205R/CG TAILRACE STRUCTURAL DESIGN CRITERIA
4027R/20SR/CM
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .0. 15800
SUBSTATION
STRUCTURAL DESIGN CRITERIA
PART B, SECTION 8.0
REVISION: 2
DATE: May 16, 1988
STONE & WEBSTER ENGINEERING CORPORATION
ANCHORAGE, ALASKA
SUBSTATION STRUCTURAL DESIGN CRITERIA
SECTION
8.1
8.2
8.2.1
8.2.2
8.2.3
8.3
8.3.1
8.3.2
8.4
4027R/205R/CM
PART B-8
SUBSTATION
STRUCTURAL DESIGN CRITERIA
TABLE OF CONTENTS
TITLE
FUNCTIONAL DESCRIPTION
SUPPLEMENTAL DESIGN CRITERIA
Materials
Loadings
Load Combinations
ENGINEERING/DESIGN CONSIDERATIONS
CGIS Building
Transformers
DESIGN GUIDELINES AND REFERENCES
PAGE
B-8-4
B-8-4
B-8-5
B-8-5
B-8-6
B-8-7
B-8-7
B-8-8
B-8-10
SUBSTATION STRUCTURAL DESIGN CRITERIA
8.0 SUBSTATION
PART B-8
SUBSTATION
STRUCTURAL DESIGN CRITERIA
8.1 FUNCTIONAL DESCRIPTION
B-8-1
The substation will consist of a Compact Gas Insulated Substation
(CGIS), transformers and line terminations on the powerhouse from
the_ transmission system. The substation is adjacent to and tied
into the north wall of the powerhouse and as such may be considered
an extension to the powerhouse.
The Compact Gas Insulated Substation will be" housed in a reinforced
concrete extension of the powerhouse and will consist of a 115 kV, 4
breaker ring bus as described in the Project Electrical Design 1·
Criteria. The substation area will serve as the line terminals for
two power transmission circuits which will take off from the
powerhouse to the local utility transmission system.
Three main unit power {115 kV) transformers are to be mounted on
concrete pads, located adjacent to the north wall of the extension
housing the CGIS system. The transformers will be provided with
separation walls and containment basins filled with crushed rock.
The transmission system design criteria and design is being
developed by Dryden & LaRue, Inc.", Anchorage, Alaska.
4027R/205R/CM SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-2
8.2 SUPPLEMENTAL/DESIGN CRITERIA
8.2.1 Materials
Refer to Part A of this Criteria.
8.2.2 Loadings
The following loads have been provided by the Electrical design
group for design purposes:
ITEM
Breaker
TABLE B8-l
llSKV EQUIPMENT LOADS
LOAD
2,300
Potential Transformer 1,900
Current Transformer 1!1300
Disconnect Switch 1,000
Grounding Switch 110
.Bus Duct (per lineal ft.) 200
T-Connection 950
L-Connection 700
Aerial Bushing Assembly 1,200
lbs
lbs
lbs
lbs
lbs
lbs
lbs
lbs
lbs
The substation building is considered a critical structure because
of the contents and because the nort~ wall of the building acts as a
protective barrier against transformer fires. Penetrations through
the exterior walls shall be sealed against firespread.
4027R/205R/CM SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-3
The substation shall be designed for the following loads in addition
to the equipment loads of Table B8-l:
LOAD TYPE
Snow (S)
Snow (S)
Wind, (W)
Live (L)
TABLE B8-2
DESIGN LOADS
LOAD
85 psf
110 psf
See Part A
300 psf
0.75 g
0.5 g
REMARKS
Regular roof load
Drift load
Use same as
powerhouse
Main floor area &
.vestibule floor area
Critical structure:
horizontal acceleration
Critical structure:
vertical acceleration
Seismic loads shall be applied pseudostatically.
8.2.3 Load Combinations
Design of the building shall consider the following minimum load_
combinations.
, CASE COMBINATION
Case 1 D + L + S
Case 2 D + w
Case 3 D + L + + w + 0.50S
Case 4 D + L + 0.50W + s
Case 5 D + L + 0.50S + El
Case 6 D + L + 0.50S + E2
4027R/205R/CM SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-4
The designer shall use either ANSI A58 .1-82 or Department of Army
Publication ETL 110-3-317 11 Engineering and Design Snow Loads" to
develop limits of drift loads.
8.3 ENGINEERING/DESIGN CONSIDERATIONS
8.3.1 CGIS Building
The CGIS building will be approximately 25 ft wide by 72 ft long by
34 ft high (inside dimensions). The structure will be constructed
with reinforced concrete walls and structural steel framing
supporting a standing seam roof system, sloped to the north (away
from the powerhouse) at 1:12.
The south wall will be common to the north wall of the powerhouse
and will extend above the termination of the siding at El 42. The
north wall of the substation will form the back wall to the
, transformer pi ts 9 and as such will be of sufficient depth and
strength to wi-thstand the effects of a transformer fire as well as
other external forces imposed on it.
The building's floor will be accessible from the powerhouse at the
El -21 level-through double doors. Access to the outside will be by
rolling steel-doors on the west end of the building at the vestibule.
The Substation equipment will be installed' such that space is
available for expansion to accommodate a future third powerhouse
generating unit.
4027R/205R/CM · SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-5
An underhung 3-ton bridge crane will be provided and will be
suspended from the roof framing, running east and west.
A vestibule area within the CGIS building will be used as an entry
point to the powerhouse and will limit traffic through the CGIS
building.
8.3.2 Transformers
Three 115 kV transformers will be located adjacent to the substation
building; two will be operational, the third will be a spare with
provisions for becoming the future Unit 3 transformer. The north
wall of the substation building will form the back wall of the
protective barrier around the transformers. Each transformer shall
be separated from adjacent transformers by a barrier wall designed
to contain and restrict explosion effects of a transformer. Each
transformer will be seated and anchored to a reinforced concrete
pad. A containment basin will be provided to contain spilled oil
should a transformer rupture. Spilled oil will be drained out of
the basin to the oily water sump in the powerhouse (refer to the
Project Lead Power Engineer for detailed drainage information). The
basin will be filled with crushed rock. The following is provided
as information and directive for the design of the transformer, the
spill basins, and the protective walls.
1. Refer to Part A, Table 3 for weights.
2. Refer to the Project Lead Electrical Engineer for physical
sizes of transformers to be assumed for design.
3. No oil spilled shall enter waterways or groundwater.
4027R/205R/CM SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-6
4. The fire barrier walls between transformers shall be a minimum
of one foot above the transformer bushings. The divider walls
shall be tied to the back wall.
5. A full deluge spray system will be provided.
6. Refer to SWEC Power Division Technical Procedure PTP-80.1.1-0,
"Fire Prevention Design and Fire Protection for Fossil-Fueled
Power Generating Stations".
7. The spill containment shall be 24 to 30 inches deep to provide
sufficient freeboard and adequate depth of crushed rock.
Estimated transformer oil volume is 6500 gallons per
transformer. The spill containment will be heat traced to
limit and reduce freezing. Size shall consider that spilled
oil is being drained off and will be sized accordingly.
Information on the oil removal system shall be confirmed with
the Project Lead Power Engineer.
8. Refer to the Project Lead Geotechnical Engineer for criteria
concerning angle of internal friction of rock/soil, rock bolt
requirements, bearing capacity, and foundation limits and
conditions.
The transformer foundations, spill containment structure, and fire
walls shall be designed, as a minimum, for the following load cases:
CASE
Case 1
Case 2
Case 3
Case 4
4027R/205R/CM
COMBINATION
D + S
D + W
REMARKS
Use 0.75g horizontal
Use 0.5g vertical
SUBSTATION STRUCTURAL DESIGN CRITERIA
B-8-7
8.4 DESIGN GUIDELINES AND REFERENCES
1. Design Criteria for Transmission System -Dryden & LaRue, Inc.
-2. Geotechnical Design Criteria, Bradley Lake Hydroelectric Project
3. Electrical Design Criteria, Bradley Lake Hydroelectric Project
4. PTP-80 .1.1-0 -Fire Prevention Design and Fire Protection for
Fossil-Fueled Power Generating Stations, 1980.
5. U.S. Army Corps of Engineers, "Engineering and Design Snow
Loads", ETLll0-3-317.
6. American National Standard Institute (ANSI), American National
Standard Minimum Design Loads for Buildings and Other
Structures, ANSI ASB.l-1982.
4027R/205R/CM SUBSTATION STRUCTURAL DESIGN CRITERIA
SECTION 5.0
ARCHITECTURAL
DESIGN CRITERIA
3116/168R/CG
. ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .0. No. 15800
ARCHITECTURAL DESIGN CRITERIA
REVISION: 2
DATE: March 23, 1988
STONE & WEBSTER ENGINEERING CORPORATION
DENVER, COLORADO
ARCHITECTURAL DESIGN CRITERIA
SECTION
1.0
2.0
2.1
2.2
2.3
3.0
3.1
3.1.1
3.1.2
3.1.3
3.1.4.
3.1.5
3.1.6
3.1. 7
3.1.8
3.2
3.2.1
3.2.2
3.2.2.1
3.2.2.2
3.2.2.3
3.2.2.4
3.2.2.5
3.2.2.6
3.2.3
3.3
3.4
3.4.1
3.4.2
ARCHITECTURAL DESIGN CRITERIA
TABLE OF CONTENTS
ITEM
GENERAL
REGULATIONS, CODES, STANDARDS AND GUIDES
LOCAL, STATE, AND FEDERAL CODES AND REGULATIONS
INDUSTRY CODES AND STANDARDS
DESIGN GUIDES
ARCHITECTURAL DESIGN CRITERIA
ARCHITECTURAL MATERIALS
General
Siding
Insulation
Roofing
Hatches, Doors and Louvers
Fireproofing
Interior Finishing
Windows, Glass, and Glazing
ARCHITECTURAL DESIGN
Facility Design/Performance Requirements
Site Data
Siting Condition
Climate/Microclimate Conditions
Aesthetic Requirements
Space and Room Requirements
Security Requirements
Access and Egress
Accessory Requirements
CODE CHECK
COLOR REQUIREMENTS
General Coatings
Siding Coating System
PAGE
1
1
2
2
3
3
3
3
4
4
5
5
6
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3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 1
ARCHITECTUAL DESIGN CRITERIA
1.0 GENERAL
This document provides architectural design criteria and information
necessary to design the Bradley Lake Hydroelectric facility for the
Alaska Power Authority.
The structure of prime consideration from the architectural standpoint
will be the powerhouse, which is a UBC Group B, Division 4 building of_
Type II-N construction. This structure will be approximately 80 feet
wide by 160 feet long by 90 feet high and will be located near Sheep
Point on the east shore of Kachemak Bay. A power tunnel will supply
water from Bradley Lake under high head to power two Pel ton type
turbines within th~ powerhouse. Consideration will be given to
extending the powerhouse by an additional 80 feet in length in the
future to house a third unit. Additional structures on the project
which will incorporate these design criteria presently include the
substation, the power tunnel gatehouse, the diversion tunnel
gatehouse, and the diversion outlet portal structure. Refer to the
General Project Information and Civil Design Criteria and the
Structural-Design Criteria, Part A, Section 1.0 for principal features
of the project. Those i terns that are identified by an asterisk (,-c)
are criteria set or provided by the Alaska Power Authority.
2.0 REGULATIONS, CODES, STANDARDS, AND GUIDES
Unless otherwise stated, the design of all structures shall conform to
the latest editions of the applicable codes and specifications listed
below.
Jll6/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 2
2.1 LOCAL, STATE, AND FEDERAL CODES AND REGULATIONS
AAC
OSHA-AK
OSHA-US
DOT/PF 1982
Alaska Administrative Code, Section 13AAC50,
(incorporates UBC provisions for Alaska State
building code requirements).
General Safety Code, Vol. I, II, and III,
Occupational Safety and Health Standards, Alaska
Department of Labor, Division of Occupational
Safety and Health, 1973 and as amended in 1983 and
the Construction Code, 1974 and as amended in 1982.
U.S. Department of Labor Occupational Safety and
Health Administration, OSHA 2206 General Industry
Standards (29 CFR 1910), and OSHA 2207
Construction Industry (29 CFR 1926/1910), as
supplement to the State of Alaska's General Safety
Code.
Alaska Department of Transportation and Public
Facilities, Design Standards for Buildings.
2.2 INDUSTRY CODES AND STANDARDS
AISC
MANUAL.
NFPA
UBC
3116/168R/CG
Manual of Steel Construction; American Institute
of Steel Construction (AISC), 8th Edition.
National Fire Protection Association -Latest
Guidelines and Requirements.
Uniform Building Code; International Conference of
Building Officials, 1985 Edition.
ARCHITECTURAL DESIGN CRITERIA
2.3 DESIGN GUIDES
SWEC
CRITERIA
R&M
CRITERIA
Page 3
Bradley Lake Hydroelectric Project:
General Project Information and Civil Design Criteria
Structural Design Criteria
Mechanical Design Criteria
Electrical-Design Criteria
Civil & Facilities Design
Hydroelectric Project, R&M
Anchorage, Alaska, 1985
Criteria, Bradley
Consultants,
Lake
Inc.,
En vi ronmen tal Atlas of Alaska, by C. W. Hartman and P.R. Johnson,
University of Alaska, 1978.
3.0 ARCHITECTURAL DESIGN CRITERIA
3.1 ARCHITECTURAL MATERIALS
3.1.1 General
To minimize maintenance problems and meet the functional concept of a
minimally maintained facility, all architectural materials specified··
or recommended for construction shall be considered on the basis of
being maintenance free with a maximum durability and the economic
minimum of replacement or repair required. In addition, selection of
accessories and materials should be made in such a manner as to
maximize preassembly and minimize construction time, where practical.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 4
Whenever possible, materials or accessories readily available in
Alaska will be provided. Concrete block walls should be avoided at the
site, if possible.*
3.1.2 Siding
Metal siding shall be insulated, factory assembled, and will consist
of an inner metal liner panel, insulation, and an outer metal face
panel. The -panel system shall achieve an R-value meeting the
requirements as given below. Metal panels shall be roll formed from
minimum 22 gauge metal sheets. Metal siding shall be steel, not
3.1.3 Insulation
A. Thermal Insulation
Thermal insulation shall be sufficient to provide the exterior walls
of all occupied structures with a minimum thermal resistance of R-19,
(no greater than U=O.OS2 BTU/Hr/Sq. Ft. /Degree F). Thermal insulation
for the roofs of occupied structures shall provide a minimum thermal
resistance of R-30,(no greater than U=0.034 BTU/Hr/Sq. Ft./Degree F).
The power tunnel gatehouse and diversion tunnel gatehouse shall be
provided with thermal insulation in the exterior walls and ceiling
with a minimum thermal resistance of R-6.
B. Acoustical Insulation
Acoustical insulation shall be used in all interior walls separating
noisy equipment areas from manned areas (such as main plant areas from
control room or lunch room).*
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 5
3 .1. 4 Roofing
Metal roofing systems shall consist of an insulated field-assembled
roofing system, consisting of a steel roof deck covered with a vapor
barrier, then foam or fiberglass insulation and capped with a steel
corrugated standing seam panel fastened to the roof deck and roof
framing. Metal roof deck shall be roll formed from minimum 22 gauge
metal sheets, and face panels shall be formed from minimum 24 gauge
metal sheets. Overlapping panels shall be fully caulked against water
intrusion.
~inimum roof slope shall be 1V:l2H; where feasible a 3V:l2H roof slope
should be considered, for snow shedding.
3.1.5 Hatches, Doors and Louvers
A. Hatches
All hatches located where personnel walk shall have a raised diamond
walking pattern or shall be covered with a non-slip surfacing.
Hatches located on exterior surfaces of heated buildings shall be
insulated.
B. Rolling Steel Doors
Rolling steel doors for the powerhouse shall be motor-operated, steel
doors with the motor located on the warm side of the opening. A
safety chain shall be provided for motor operated rolling steel doors
for manual operation. Exterior rolling steel doors shall be insulated.
Rolling steel doors for the gatehouses shall be chain operated.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 6
C. Standard Leaf Doors
Exter"ior doors -shall be insulated hollow metal doors. Interior doors
shall be hollow metal or solid wood core doors, as applicable.
D. Fire Doors
All doors in fire rated walls shall bear an Underwriter's Laboratory
fire label.
E. Louvers
Louvers· shall be designed to resist the same wind pressures as the
adjacent walls.
3.1.6 Fireproofing
Classification of fire rated assemblies for walls, floors, ceilings,
beams and columns shall be in accordance with the Uniform Building
Code and Stone & Webster guidelines.
Fireproofing of exposed structural steel members at fire rated
enclosures will be a cementi tious type except at drywall partition
enclosures where 5/8" Type X drywall will be used. All gypsum
wailboard used in the plant will be 5/8" Type X fire-rated.
3.1.7 Interior Finishing
A. Interior walls will be const-ructed of gypsum wallboard attached
to metal wall studs. Where a more durable finish is required,
such·as in the machine shop, a metal face panel will be used.*
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 7
B. Suspended acoustical tile ceilings will be used .in office areas,
control room, and lunch room.
ceiling shall be designed
activities.
The framework for the acoustical
and braced to accommodate sei-smic _
c. An access floor will be provided in the control room for cable
spreading purposes. All floors in office spaces, control room,
and lunch room shall be faced with sheet vinyl composition tile.
The floors and walls in the locker room will be faced with
ceramic tile.
3.1.8 Windows, Glass and Glazing
Windows in exterior walls shall be operable·, except that fixed windows
shall be used in the control room, and shall be . double glazed with
1/2" airspace.'i~ Windows in interior walls shall be sound deadening
plastic laminated glass to reduce sound transmission through walls.
3.2 ARCHITECTURAL DESIGN
3.2.1 Facility Design/Performance Requirements
For the purpose of selection of support facilities, the plant
operations staff shall be assumed as follows: The regular staff at
the project will consist of one plant supervisor and three maintenance
personnel. 'i~ Because of the remoteness of the project, these workers
will be provided with permanent housing near the powerhouse.
Occasionally, maintenance crews will be brought in to provide general
and heavy maintenance and repairs to project facilities. These crews
will be housed in a 6-bedroom dormitory/office building located near
the regular staff quarters .
. 3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 8
The powerhouse will be designed to be operated as a remote control
facility. The prime function of the regular staff will be to monitor
plant f1mctions and perform minor maintenance tasks. The powerhouse_
will be designed such that it need not be staffed on a 24-hour per day
basis.
Since the facility is located in a seismically active area, particular
attention shall be paid to adequate attachment of architectural
fixtures, accessories, and equipment. Reference shall be made to the
Structural Design Criteria requirements when specifying or selecting
accessories and when detailing or identifying attachments for these
items.
3.2.2 Site Data
3.2.2.1 Siting Condition
The powerhouse will be built approximately at sea leveL The terrain
to the north, east and south of the powerhouse is heavily wooded and
rises gradually. The area to the west consists of mud and tidal flats
and swamp areas with a reach of approximately four miles to bluffs
across Kachemak Bay. The area is currently undeveloped and
inaccessible by land vehicles, but is accessible by air and water. An
onsite access road will be developed to run from the barging
facilities and base camp to the powerhouse site and to the facilities
at Bradley Lake.
3.2.2.2 Climate/Microclimate Conditions
For general climatology, refer to the General Project Information and
Civil Design Criteria.
3ll6/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 9
A. Heating Design Temperatures
1. Powerhouse
Winter heating design temperature = -l0°~k
Powerhouse interior temperature = 72°F for occupied control
room, lunch room, locker room and office areas,,.c and 65°F for
normally unoccupied areas (with residual equipment heat and -l0°F
outside ambient). Waste heat from the equipment will be used to
heat the Powerhouse. This will be supplemented by auxiliary unit
heaters when the Powerhouse is not operational.
2. Other Structures
Facilities other than the Powerhouse will generally be heated by
local unit heaters. The working environment within manned
facilities should be maintained at 65°F. Insulation and heating
requirements shall be developed to maintain acceptable
temperature
equipment.
levels required to assure full operation of
Refer to the Mechanical Design Criteria.
3. For additional information, refer to the Project Mechanical
Design Criteria.
B. Lighting
The lighting requirements for each facility will be specified in
the Project Electrical Design Criteria. Natural lighting will
augment artificial lighting where appropriate.
3.2.2.3 Aesthetic Requirements
A clean, but not sterile, appearance is desired. Facilities requiring
little or no manning will still be required to be coordinated so as to
promote reasonable aesthetics.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 10
All faci 1 it ies shall be planned so the exterior pat tern promotes a
blending· with the surrounding area, minimizing visual impact to the
site. All ·exterior color schemes and wall patterns shall be reviewed
and approved by the Alaska Power Authority.
3.2.2.4
A.
Space and Room Requirements
Personnel Facilities
A control room for the Powerhouse will be situated to overlook
the generator floor and will house the control panels, SCADA
computer, and communications equipment.* An office will be
located adjacent to the control room for the use of the plant
supervisor.* A lunch room complete with sink, refrigerator,
stove, microwave, storage cabinets, and counter space will be
provided for the regular staff adjacent to the control room.* A
restroom will be provided including one lavatory 9 one water
closet, and one urinal, and a locker room will be provided
including one semi-circular wash basin, lockers and one shower.*
A separate single water closet and lavatory will be available
adjacent to the control room for female personnel and/or
visitors.~c -Handicapped facilities will not be provided in the
Powerhouse . ~c ·
B. Miscellaneous Support Services
The following support services shall be provided in the
Powerhouse:
1. Local first aid stations
3116/168R/CG
(It is not intended that a separate first aid room be
required. As a minimum, adequate first aid supplies will
be stored within the lunch room. ~c First aid supplies will
be furnished by the Owner.*)
ARCHITECTURAL DESIGN CRITERIA
2. Emergency eye wash and shower located adjacent to
battery room
Page 11
3. Tool-boards located at ·various locations near equipment
which requires frequent maintenance to facilitate work.~'
Specialty tool boards will be provided by the equipment
manufacturers.~"' Other tool boards, where required, will be
supplied by the owner.*
C. Machine Shop/Tool Room
A machine shop will be provided in the Powerhouse and will be
used to repair minor machines and some equipment.* Major repairs
will be accomplished in the warehouse or vehicle shop or will be
made offsi te. A two-ton hoist on monorail shall be provided in
the machine shop.* The machine shop will be sized and wired to
accommodate the following owner-furnished equipment~':
1. Metal lathe
2. Drill press
3. Brake press and shear
4. Band saw
5. Grinder
6. Work benches
7. Storage cabinets
8. Tool boards
D. Electrical Shop
An electrical/instrumentation shop area will be provided in the
Powerhouse for repair and servicing of electrical equipment.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 12
E. Storage Rooms
-Storage rooms for files will be provided in the Powerhouse t where
appropriate.
F. Furnituret Equipmentt and Appliances
3.2.2.5
The Archi teet shall prepare a list of appliances for purchase
under the Powerhouse Construction Contract. Unattached
furnishings such as office furnituret work benchest storage
shelves and cabinetst etc.t will be supplied by the Owner.*
Security Requirements
Security philosophy shall be reviewed with the Alaska Power
Authority. As a minimumt the following shall be provided:
1. Exterior entrances to all buildings shall be lockable with high
quality deadbol t locks operated from the outside and by turning
from inside. Exterior and security mandoors at the Powerhouse
shall be provided with locksets that have both a key lock and a
push button combination lock.
2. Selected rooms or areas within buildings may require locksets.
3. A master key plan shall be developed to operate all locks within
the facility. Master keys shall be provided to the Alaska Power
Authority.
The remote location of the site precludes the need for guards.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA
Page 13
3.2.2.6 Access and Egress
Egress requirements shall be in accordance with Chapter 33 of the
Uniform Building Code, as applicable, unless a specific variance is
obtained from the State Fire Marshal. The distance between exits
shall not be less than 1/2 of the longest diagonal of the building,
but shall not exceed 150 feet.
Mandoors at the gatehouses shall open inwards, due to potential snow
.accumulation at the exterior face.*
3.2.3 Accessory Requirements
The following information is provided to assist in the planning,
design, and detailing efforts on the project:
A. Standard Stairs (Powerhouse)
Nominal stair width shall be 44 inches, unless otherwise noted.*
Handrail height above nosing shall be 34 inches. Handrails on stairs
shall be provided with three rails to match standard handrails at
platforms.
Maximum vertical distance between landings shall be 12 feeto
Treads used outside shall be open ·grating or safety grip grating. ~r
Treads used indoors shall be checked plate steel treads. ~r A safety
nosing shall be provided.
3ll6/168R/CG ARCHITECTURAL DESIGN_CRITERIA
Page 14
B. Ladders
Ladders shall be in accordance with OSHA requirements. Maximum height
of ladder without cage above floor or roof shall be 20 feet. Maximum
run of ladder without intermediate platform shall be no greater than
30 feet.
C. Standard Handrails (Powerhouse)
Handrails around open platforms, landings, and floor openings shall be
42 inches high; openings in a handrail shall .not permit a 12 inch
diameter~ sphere to pass through. Standard handrail shall be 1 1/2"
diameter pipe handrail.
D. Louvers, Screens and Hoods
For the Powerhouse, stormproof louvers will be used to reduce rain and
snow infiltration. Bird screens will be provided to prevent nesting
in the, louvers (insect screens are not required).
E. Roof Installations
Mounting of equipment on roofs shall be held to a minimum.· If a roof
penetration is required, the equipment shall be mounted on a minimum
six-inch high curb, and the penetration shall be fully flashed.
Manufacturer's details should be used whenever possible. In all cases .. I
roof penetrations shall be flashed, including those for pipes and
vents.
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA ·
Page 15
F. Cabinetry and Counters
--Kitchen facilities shall include built-in wooden cabinets with plastic
laminate counters.
Locker room lavatory shall be built into a wood vanity with plastic
laminate counter top.
3.3 CODE CHECK
All buildings shall be in conformance with the applicable codes. For
the Powerhouse, a review of applicable code requirements will be made-.I .
based on Section 8 of the State of Alaska, Department of
Transportation & Public Facilities (DOT/PF) document Design Standards
Manual for Buildings.
3.4 COLOR REQUIREMENTS
3.4.1 General Coatings
A. Color· Scheme
The external coior scheme shall be selected to blend the subject
structure with the natural environment.* Colo~ of doors will contrast
with base building color to be easily located.
Generally, interior colors shall be soft, warm colors. The Archi teet
shall develop a color coordinated scheme acceptable to the Alaska
Power Authority, which will evaluate color requirements for at least
the following.:
3116/168R/CG ARCHITECTURAL DESIGN CRITERIA .
Page 16
1. All walls and ceilings
2. Structural and miscellaneous steel
3. Color requirements for equipment
4. Safety colors for special areas or equipment
5. Underside of decking and roof
6. Suspended acoustical ceiling
7. Resilient flooring
8. Ceramic floor and wall tiles
9. Countertops and cabinet work
B. Galvanizing
The following items will be hot dip galvanized:
1. Stair treads
2. Open grating
3. Selected plate material
4. Exterior pipe handrail
3.4.2 Siding Coating System
Colors are as follows:
Exterior face panels -Sea Foam ( 1731 by Robertson Siding which
closely mat"ches Desert Beige as used on worker's facilities and.
warehouse)*
Interior liner panels -Arctic Ice (5913 by Robertson Siding)
3l16/168R/CG ARCHITECTURAL DESIGN CRITERIA
I
SECTION 6.0
GEOTECHNICAL
DESIGN CRITERIA
5168R/LS.-
ALASKA POWER AUTHORITY
BRADLEY LAKE HYDROELECTRIC PROJECT
J .0. NO. 15800
MIDDLE FORK AND NUKA DIVERSIONS
GEOTECHNICAL DESIGN CRITERIA
REVISION: 0
DATE: July 19, 1988
.,
STONE & WEBSTER ENGINEERING CORPORATION
GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
Section
1.0
1.1
1.2
1.2.1
1.2.2
1.2.3
2.0
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
-5168R/LS
MIDDLE FORK AND
NUKA DIVERS IONS
GEOTECHNICAL DESIGN CRITERIA
TABLE OF CONTENTS
Section Title
MIDDLE FORK DIVERSION
Summary Description
Design Criteria
Excavation Design
Channel Alignment
Waste Fill Slope Protection
NUKA DIVERSION
Summary Description
Design Criteria
Gabion Structure
Earth Dikes
Slope Protection
Ice Loads
Page No.
1
1
1
1
1
2
2
2
3
3
3
4
4
GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
Page 1
1.0 MIDDLE FORK DIVERSION
1.1 SUMMARY DESCRIPTION
The Middle Fork Diversion is located approximately one mile north of
Bradley Lake at Elevation 2160 on the Middle Fork Tributary of the Bradley
River. The Middle Fork Diversion will consist of an intake basin within
the Middle Fork River Channel and an upper channel excavated in rock, and a
stilling basin and a lower channel which are excavated. in overburden. The
diversion channel will operate year round ·and will convey water from the
Middle Fork of the Bradley River to Marmot Creek, a tributary to Bradley
Lake.
1.2 DESIGN CRITERIA
1.2.1 Excavation Design
Overburden excavation slopes of the channel shall be designed at a slope of
2 Horizontal to 1 Vertical.. The slope shall be adjusted to 3 Horizontal to
1 Vertical as required by less stable soil conditions defined during
construction.
Rock. excavation slopes shall be designed at 1 Horizontal to 4 Vertical.
Because this is a .noncritical structure which does not impound water,
seismic design requirements will not be used in the design of the ·
excavation of the channel.
1.2.2 Channel Alignment
The Middle Fork Diversion Channel is .to be aligned to accomplish the
following:
1) Minimize the length of the channel (and therefore the
environmental impact) and
2) Provide the desired flow characteristics (see Hydraulic Design
Criteria).
5168R/LS GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
Page 2
The following design parameters shall have the identified values:
Diversion Channel
Design Parameter
Gradient
Curve Radius
Channel Cross Section
1.2.3 Waste Fill Slope Protection
Requirement
See Hydraulic Design Criteria
Minimum 100 ft
See Hydraulic Design Criteria
Waste fill areas shall be covered with a minimum of 6 inches of shot rock
to control potential erosion.
2.0 NUKA DIVERSION
2.1 SUMMARY DESCRIPTION
Nuka Pool is a pond fed by glacial melt located at the terminus of the Nuka
Glacier. Nuka Pool lies on the divide between two. drainages, discharging
water into the Upper Bradley River and the Nuka River. Water discharged
into the. Upper Bradley River flows to Bradley Lake and that which is
discharged into the Nuka River flows to the Kenai Fjords National Park.
' .The Nuka Diversion elements will direct the first 5 Cfs of available flow.·
from the Nuka Pool into the Nuka River. Flow in excess of 5 cfs will be
directed to the Upper Bradley River.
The diversion elements consist of an earth-fill dike, gabion structure and
open pipe to control flow to the Nuka River and an enlargement of an
existing natural rock weir outlet at the Upper Bradley River end of the
pool. A second closed pipe is available at the gabion control structure
for future potential increase of minimum required flow to the Nuka River.
5168R/LS. GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
Page 3
2.2 DESIGN CRITERIA
2.2.1 Gabion Structure
A gabion structure containing 2 discharge pipes will be incorporated into
the dike at the Nuka River Channel. The purpose of this structure is to
minimize the pipe lengths and provide an approach and discharge channel of
sufficient water dep.th to prevent icing of the discharge pipe(s).
Gabion fill will consist of shot rock from the rock weir excavation or
geote~tile wrapped dike fill soils. Geotextile wrapped gabion fill exposed
to the elements will require additional protection. All such gabion
surfaces not in contact with soi 1 or other gab ions sh~ll be-protec-~ed _from -----·--· ··-·---
degradation by insertion of galvanized steel sheets or shall be filled with
soil cement.
2.2.2 Earth Dikes
Dikes will be constructed of adjacent unprocessed overburden.
Dikes shall be designed with unprotected side slopes of 4 Horizontal to 1
Vertical which approximate the natural existing slopes of the proposed dike
material. A limited number of steeper slopes up to 3 Horizontal to_ L-
Vertical where used shall be protected from erosion.
The Nuka Diversion will not impound water but rather redirect it from one
drainage basin to another, therefore seismic design requirements will not
be used in the design of the dikes.
The dikes will be aligned to minimize the amount of fill required.
Dike seepage cutoff will consist of a membrane liner and shall only be
included below the existing ground surface at the Nuka River Diversion
Channel. Because the remaining dikes are low head structures (maximum 3
feet) leakage is not expected to be significant.
5168R/LS GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
Page 4
2.2.3 Slope Protection
Permanent fill slopes steeper than 4 Horizontal to 1 Vertical shall be
protected from erosion. Slope protection will consist of rock cover,
gabions or Geo Web elements.
2.2.4 Ice Loads
The Upper Bradley River outlet will be designed as a rock weir to be
constructed by improving the existing natural rock weir. If a concrete
weir is to be designed then an ice load of 12 kips/linear foot shall be
used to calculate the required anchorage force for the structure.
5168Rf:LS GEOTECHNICAL DESIGN CRITERIA/
MIDDLE FORK AND NUKA DIVERSIONS
SECTION 7.0
ELEC'IRICAL
DESIGN CRITERIA
ALASKA POWER AUTHORITY
ANCHORAGE, ALASKA
BRADLEY LAKE HYDROELECTRIC PROJECT
ELECTRICAL DESIGN CRITERIA
J.O. 15800 REVISION: 1
DATE: JANUARY 13, 1987
STONE & WEBSTER ENGINEERING CORPORATION
Anchorage, Alaska
[15800, EDC, 06/28/88]
00696AA-1580072-Dl
Revision 1
Notes on revisions to Electrical Design Criteri~
Changes in the Electrical Design Criteria, made after initial
issue, are marked by an asterisk { *) in the right margin. The
changes to the design criteria are listed below.
Section 1
Part 2.2.1, page 1-2,
Part 2.2.1, page 1-3,
Part 2.2.1, page 1-3,
Part 2.2.2, page 1-4,
Part 2.2.3, page 1-5,
Part 2.2.3, page 1-5,
Part 2.2.3, page 1-5,
Part 2.2.3, page 1-5,
Part 2.2.3, page 1-6,
Part 2.2.3, page 1-6,
Section 2
Part 2.1, page 2-1,
Section 3
Removed reference to aluminum conduit.
Allow only flex fittings across joints.
Allow PVC coated steel for direct burial.
Combined two paragraphs.
Removed reference to concrete encasing,
changed Type 40 {EPC) to PVC coated steel.
Changed size from 6 inches to 2 inch
minimum.
Removed reference to concrete-encased ducts.
Removed reference to client and stock.
Changed to consider bending radius of all
cables.
Removed reference to earth cover.
Remove standard for aluminum conductor.
. Part 2.2, page 3-2, Typographical error on d-e lighting.
Part 2.3.5, page 3-5, Removed refer~nce to Scotchlock connectors.
Part 2.3.8, page 3-5, Replaced specification grade with hospital
Section 4
Part 2.4.1, page 4-2, Expanded to include system at darn site.
Part 2.5, page 4-7, Allow ground loops where necessary.
Appendix A-1, pg 4-9, Removed reference to tinned copper.
Section 6
Part 2.2.2, page 6-1, Have PP/PA integral part of phone ~ystern.
Part 2.2.3, page 6-2, Added 2 channel system at darn site.
Part 2.2.4, page 6-3, Removed reference to specific n~rnber of
phones.
Section 12
Part 2.4, page 12-2, Have fire stops repaired immediately.
[15800, EDC, 06/28/88]
00696AA-1580072-Dl
Section
1
2
3
4
5
6
7
8
9
10
11
12
..
TABLE OF CONTENTS
Title
Foreword
Raceway Systems
Insulated Wire and Cable
Lighting System
Grounding System
Cathodic Protection
Communication Systems
Metering and Relaying
Critical AC System
Station Service System
DC Systems
Substation
Fire Stops and Seals
[15800, EDC, 06/28/88]
00696AA-1580072-Dl
FOREWORD
1.0 PURPOSE
This Electrical Design Criteria is prepared to define
guidelines, codes, and industry standards that will be
followed in the design and construction for the Bradley Lake
Hydroelectric Project. It is intended to be used as input
to procurement specifications, construction drawings,
installation instructions, and erection specifications.
2.0 CODES AND REGULATIONS
NFPA-70, the 1984 National Electrical Code (NEC), will be
used as a design guideline. Although design and construc-
tion methods will be based on NEC methods, the powerhouse is
exempted from NEC requirements by Article 90, paragraph
90-2b(5) of NEC and specific exceptions will be taken when
appropriate. Other governing codes and standards will be
referenced as needed in the appropriate section.
3.0 SITE CONDITIONS
All equipment and systems will be designed for use in a
utility power plant located on the southern part of the
Kenai Peninsula, approximately 27 miles northeast of Homer,
Alaska and approximately 105 miles south of Anchorage,
Alaska. The powerhouse will be located along the shore of
Kachemak Bay. Site temperatures range from -38 to 85
degrees F. Average indoor humidity will be held to within
95% relative humidity, non-condensing by the HVAC system.
All equipment and structures will be designed to withstand a
seismic event in accordance with UBC Zone 4.
[15800, EDC, 06/28/88]
00696AA-1580072-Dl
Section
1.0
2.0
2.1
2.2
2.3
3.0
4.0
2.2.1
2.2.1.1
2.2.1.2
2.2.2
2.2.3
2.2.4
SECTION 1
RACEWAY SYSTEMS
Title Page
DESCRIPTION 1-1
ENGINEERING/DESIGN CRITERIA AND
PARAMETERS 1-1
Applicable Codes 1-1
System Characteristics 1-1
Conduit Systems 1-2
Conduit Fittings 1-3
Liquid-Tight Flexible Metal
Conduit 1-3
Cable Trays 1-4
Underground Duct Systems 1-5
Outdoor Cable Trenches 1-7
Sleeves and Blackouts 1-7
LONG TERM MAINTENANCE
CONSIDERATIONS
SAFETY CONSIDERATIONS
1-7
1-8
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
RACEWAY SYSTEMS
1.0 DESCRIPTION
The raceway system consists of all equipment which encloses,
support or protects any wiring.
2.0 ENGINEERING/DESIGN CRITERIA AND PARAMETERS
2.1 Applicabl·e Codes
The latest issue of the following codes and standards ~ill
be used where applicable to the design, manufacture, and
installation of raceway systems:
NEC
ULl
UL6
UL543
UL651
UL1242
ANSI c8o.s
ANSI C80.3
NEMA TC6
NEMA BCl
NEMA VEl
National Electrical Code
Flexible Metal Conduit
Rigid Metallic Conduit
Fiber Conduit
Rigid Nonmetaliic Conduit
I~termediate. "etallic Conduit
Aluminum Alloy Rigid Conduit
Electrical Metallic Conduit
Underground Duct
Bituminized-Fibre Conduits and
Fittings for Electrical Use
Cable Tray Systems
2.2 System Characteristics
The raceway system will _provide a mean~ of supporting cable
runs between electrical equipment, physical protection to
the cables and, for a metallic raceway system, to provide a
path to ground for the noncurrent-carrying part of an
electrical system. The electrical raceways will carry
power, control, lighting, instr'umentation, and communication
cables. It will provide for the safety and accessibility of
electrical circuits. The system will also provide spare
circuit and feeder capacity for initial and future needs, as
well as flexibility to accommodate future changes and
rearrangements of cable runs.
Special care will be taken to assure that the raceway system
is adequate. The National Electrical Code (NEC) regulations
provide information for the installation of lighting systems
and electrical systems in offices, warehouses, shops,
computer rooms, elevators, switchboards and panelboards, and
temporary construction power. In addition· to safety and
ample capacity, the raceway system will provide .flexibility
to accommodate future changes in the electrical system.
1-1
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
A m1n1mum of 25 percent spare ducts will be provided in duct
banks at time of installation. Engineering judgment will be
used in providing spare capacity in raceway systems.
The metallic portion of all raceway systems will be electri-
cally continuous and grounded. Section 4 of the electrical
design criteria, 11 Grounding System 11 , defines the methods to
be used.
The rbuting of conduit runs and cable trays will be laid out
to avoid blocking passageways or access to equipment for
operation, removal, or maintenance. Wherever practicable,
exposed raceway systems shall be routed to run either
parallel or perpendicular to building structures.
2.2.1 Conduit Systems
Conduit systems will be designed to minimize the pulling
tension· of cables. Maximum length of runs, number of bends,
and spacing of pull boxes and condulets will--be predeter-
mined by the Engineers to allow cable to be _installed and
removed without exceeding permissible pull tension or side
wall pressure whichever is the lesser value, with minimum
difficulty, and without damage to cable. General rules to
be followed are that no exposed conduit will be designed
with more than four equivalent 90 degre.e bends and no
concealed conduit will be designed with ~ore than two
equivalent 90 degree bends between pull boxes or terminal
devices.·
Conduit ·system design will use junction boxes, pull_ boxes,
etc., where necessary to facilitate easy installation of
cables. Fittings of the 11 condulet 11 or 11 unilet 11 type shall
not be used as splicing points.·
Intermediate Metal Conduit (IMC) or rigid hot-dipped galva-*
nized steel conduit will be used for all exposed indoor and *
outdoor runs of power, instrumentation and control cables. *
Conduit concealed in floor slabs or otherwise embedded in
concrete structural members will be PVC and/or rigid galva-
nized steel.
Metallic conduit and fittings will be of the threaded type.
PVC conduit and fittings will be joined by means of solvent
cement.
Conduit sizes shall be based on percent fill as required by
NEC. Sizes will be 3/4 inch minimum for lighti'ng circuits
and one inch minimum for all others;
1-2
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
Where embedded conduit crosses a joint in a slab a
Crouse-Hinds XD coupling or similar fitting will be used.
If it becomes expedient to extend a conduit underground by
direct burial it will be factory PVC coated iigid steel or
PVC Type 40.
Concealed and buried conduits subject to flooding will be
sloped toward terminations for drainage.
Unused conduit will be. capped to prevent entrance of foreign
material.
In general, conduit will be shown diagrammatically on
drawings. Where required to facilitate installation or to
minimize interferen~es, the runs will be dimensioned.
2.2.1.1 Conduit Fittings
·Pull boxes and junction boxes will provide ·access points for
pulling and feeding conductors in the raceway. Boxes will
be sized in accordance with NEC article 370.
Conduit fittings will preferably be of the same basic
material as the conduit. Where necessary at connections to
small devices such as push-button stations, solenoid operat-
ed valves, etc., a _suitable box or condulet will be used to
provide proper space for cable terminations.
2.2.1.2 Liquid-Tight Flexible Metal Conduit
Flexible metal conduit will be us.ed between rigid metal-
conduit and equipment conduit boxes on all ~otors, connec-
tions to thermocouples, or in any situation where vibration
is anticipated.
Flexible conduit shall have an extruded PVC jacket and
entrance to -equipment. terminals will be made moisture-tight
by use of combination seal type PVC Coated fittings with
flexible conduit grip._
Flexible conduit length should be as short as practicable,
but not less than 1.6 times the minimum bending radii
recommended for the cable which is to be installed.
Electrical continuity between rigid and flexible conduit
will be maintained. Electrical continuity between conduit
and equipment will be provided by sui table connectors or
jumpers. Refer to Section 4, Grounding, for methods of
installing jumpers.
1-3
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-D1
*
*
*
* *
2.2.2 Cable Trays
All cable trays shall be manufacturer • s standard. Cable
trays will be ladder type, aluminum, or rigid steel. Widths
will be 6, 12, 18, 24, or 30 in. with cable loading depth of
3 or 4 in. and rung spacing of 9 in. All 90 deg bend
sections will have a minimum 2 ft. radius.
Tray covers, when used, will be side-ventilated, requ1r1ng
no derating of cable. Trays will not be located close to
heat sources unless cables are derated for the expected
temperature. Horizontal cable trays exposed to falling
debris and water, will be covered on the top tray only.
The longitudinal distance between tray supports will not
exceed 8ft. Vertical distance between stacked trays (i.e.,
bottom to bottom of tray or bottom to ceilin~) will be 16
in., unless otherwise noted on the drawings.
Bottom of tray to structural member above will be minimum 16
in.
Cable tray supports will be designed to withstand a seismic
event in accordance with UBC ZONE 4.
Supports will be designed to perform, without ·damage or
permanent deformation, loads as specified above multiplied
by safety factor of 3. 3. In addition the trays must with-
stand a point load of 250 lbs. applied at midspan without
damage or permanent deformation.
Cable trays will be given letter designations according to
service as follows:
11 L 11 trays will be used for power cable with rated circuit
voltage up to 600 v.
11 K11 trays will be used for power or control cables with no *
I 2 R losses or intermittent service (operating not more than *
40% of the time and not longer than 30 min. at any one *
operation) per ICEA P-46-426.16.17. Maximum tray fill *
will be 40% of the cross-sectional area of a 3 in. cable *
loading depth. *
11 C 11 trays will be used for control cables up to 250 volts.
Maximum fill will be 50% of the cross-sectional area based
on a 3 in cable loading depth.
11 X 11 trays will be used for low level signal instrument,
thermocouple extension or shielded control cables (50 V or
less) .
1-4
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
Most cables will leave trays from below. A standard
drop-out fitting will be used to ensure that the cable
minimum bending radius is maintained.
All cable trays will be dimensioned on the Engineer's tray
layout drawings and checked for interferences with other
plant equipment by the Engineers.
2.2.3 Underground Duct Systems
Conduits for duct banks, will be factory coated rigid steel *
directly buried in select fill. *
Ducts will be 2 in. diameter minimum. Duct fill will be *
based on 53 percent fill for one cable, 31 percent for two
cables, and 40 percent for three or more cables.
When ducts turn up for termination near
equipment foundations, or elsewhere, a
bushing will be installed flush with the
flush plug installed.
building walls,
female threaded
concrete, and a
Ducts will be spaced to provide adequate heat transfer, and
cables in ducts will be derated according to . duct
configurations.
* Standard concrete ~anholes and handholes will be used as *
required. Manhole and handhole covers will be standard *
design. Manholes shall have drains. *
Layout of the underground system will be designed to mini-
mize the number of manhole configurations required. Duct
runs will be as straight as practicable, but will avoid
major interference with foundations, pipes, etc. The
straight line route between pulling points will.be selected
without regard for being parallel or perpendicular to
building steel or underground piping. Anticipated use of
excavations common to other underground work wlll, however,
influence the routing, particularly on long runs. The
careful selection of manhole locations and orientation will
help eliminate bends.
When bends are required to avoid obstructions, they will be
located as close as possi9le to an end rather than in the
middle of the run. This applies to both horizontal and
vertical bends.
Duct lengths will be such that the maximum pulling tension
and side wall pressure recommended by cable manufacturers
are not exceeded.
1-5
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-D1
Runs requiring more bending (max 270 deg) may be used in
extreme cases, but will not exceed 50 ft. in total length.
A curve using the above points can be made to select maximum
duct run lengths for intermediate bend angles. The above
lengths are based on the assumption that the most fragile
cable used will have a maximum pulling tension of 30 lb.
Cables with less than 30 lb. max tension require either
shorter ducts or a messenger cable for installation.
Each bend will have the largest possible radius consistent
with duct configuration and material being used. Horizontal
bends are more adaptable to large radii than vertical bends
which are quite often restricted when turning up to
equipment.
The cable side wall pressures to be observed during instal-
lation usually dictate the minimum radius that can be used.
Side wall pressures will be satisfactory if the maximum
pulling tension in pounds is not more than 200 times the
minimum bend radius in feet. "
The minimum bending radius can be determined as follows:
1. For bends up to 90 deg
200 R = 1.095 WL-1.75 WR
or
R = 1,.095 WL
200 + 1.75 w
· 2. For two bends up to 90 deg each
200 R = 1.75 WL -5.5 WR
or
R = 1.75 WL
200 + 5.5 w
R = Duct radius, ft.
W = Combined unit weight of all cables to be pulled
into duct, lb/ft
L = Total length of duct, ft
(The coefficient of friction is assumed to be .5)
All cable pulling points will have covers large enough to *
permit exit and reentry of cable without compromising the *
minimum bending radius of any cable to be pulled through. *
Duct banks will have a minimum backfill cover of 2 ft. -0
in., wherever possible. In those cases where depth of duct
banks is critical to avoid interferences and heavy vehicle
loading is not a factor, a minimum earth cover of 18 in. may
be used. *
1-6
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
Duct bank standard design for power cables will not exceed
12 normally operating circuits in each bank. Larger banks
which contain both power and control cables will have the
power cables in the top row and/or in the extreme outer
vertical rows.
Spacing of ducts within the group will conform to dimensions
of commercially available spacers. The design will permit
reasonable ( 15 percent} deviations, in the spacing dimen-
sions, to allow for the use of spacer material and for
installation tolerances.
2.2.4 Outdoor Cable Trenches
Prefabricated trenches will have inside dimensions of 15 in.
deep by 20 in. wide. Top lids will be concrete or
fiberglass-concrete composition.
In areas where vehicles may cross cable trenches, the
trenches will be designed to carry the vehicle loads. :
Ample drainage will be provided for the bottom of cable
trenches to avoid constant immersion of cables in water.
The Engineers will ensure that all cables placed in cable
trenches have jackets designed to protect conductors against
immersion in water.
2.3 Sleeves and Blackouts
Sleeves and blackouts will be provided for passage of cables
through floors and walls with adequate room for additional
cables at a later date.
Location of floor and wall sleeves and blackouts will be
determined by the responsible electrical engineer -in: accor-: ,
dance with the floor and wall design of the structural
engineer.
·3.0 LONG TERM MAINTENANCE CONSIDERATIONS
The raceway system is expected to remain
life of the plant with little or no
raceway system will have sufficient
adaptable to changes.
in service for the
maintenance. The
flexibility to be
Raceways and supports will be furnished with a finish to
provide generally maintenance-free operation for the expect-
ed plant life.
1-7
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-Dl
4.0 SAFETY CONSIDERATIONS
Raceway penetrations through fire barrier walls and floor
will be sealed in accordance with section 12 of the electri-
cal design criteria, Fire Stops and Seals for Raceway
Penetrations.
1-8
[15800, Section 1, EDC, 06/28/88]
00696A-1580072-D1
Section
1.0
2.0
2.1
2.2
2.3
2.4
2.5
SECTION 2
INSULATED WIRE AND CABLE
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes
Wiring Characteristics
Wire/Cable Sizing
Installation
Testing
[15800, Section 2, EDC, 06/28/88]
00696B-1580072-Dl
Page
2-1
2-1
2-1
2-1
2-2
2-3
2-3
INSULATED WIRE AND CABLE
1.0 DESCRIPTION
Insulated wire and cable will be used to transmit and
distribute electric energy, to transmit instrumentation and
control signals, and to carry communication signals.
2.0 ENGINEERING/DESIGN CRITERIA
2.1 APPLICABLE CODES
ASTM B8
ICEA P54-440
NEMA WC-51
ICEA S-19-81
NEMA WC-3
ICEA S-66-524
NEMA WC-7
ICEA S-68-516
NEMA WC-8
NEC NFPA-70
1976 Concentric Lay Stranded Copper
Conductors; Hard, Medium or Soft
1975-R80 Ampacities, Cables in Open Top
1975-R79 Cable Trays
1978 Rubber Insulated Wire and Cable
1980-R85 for the Transmission and Distri-
bution of Electrical Energy
1978 Cross-linked Thermosetting Poly-
1982-R84 ethylene Insulated Wire and Cable
for the Transmission and Distri-
bution of Electrical Energy
1978-R82 Ethylene Propylene Rubber Insu-
1976 lated Wire and Cable for the
Transmission and Distribution of
Electrical Energy
1984 National Electrical Code
2.2 Wiring Characteristics
The basic insulation levels of 300 volt, 600 volt, 1000
volt, 2000 volt and 15,000 volt will be used for all wiring
and cabling in the station.
Solid wire will be used for lighting and convenience outlet
Wlrlng. Other wiring will be class B stranding, except for
instrument wiring which will be class C stranding. All
stranding will be as defined by ASTM B8. Switchboard wiring
will be type SIS.
Shielding will be provided for all cables that will be
energized at greater than 8000 volts. Cable shields will be
multiple point or continuously grounded whenever practical.
2-1
[15800, Section 2, EDC, 06/28/88]
00696B-1580072-Dl
*
Instrumentation cables will be specified to be shielded as
required. Grounding of instrumentation cables will be
specified to minimize electrical noise.
Multiple conductor control cables will be
select standard sizes during final design
minimize requirements for small pieces of
specified in
in order to
unique cable.
All control cables will be specified to have class three
color coding (insulation is actual color rather than just
printed on the wire).
Lighting and convenience outlets will be wired with #12 AWG
m1n1mum. Current transformers will be wired with #10 AWG
wire. D.C. control circuits cables will utilize the equiva-
lent of #14 AWG wire minimum.
All wire and cables whether installed in cable trays or in
conduit will be provided with thermosetting insulation and
jacket materials that will meet the ICEA Vertical Flame Test
and the IEEE standard 383 Cable Tray Fire Test. Insulation
materials will be based on 90°C continuous conductor temper-
ature in an ambient temperature of 30°C.
All wire and cable will be copper.
2.3 Wire/Cable Sizing
Cables rated 0-2000 volts will be sized according to table
310-16 of the National Electrical Code, with all appropriate
derating notes applying, depending on the installation of
the particular cable.
Cables rated greater than 2000 volts will be sized according
to NEMA standard WC-51/ICEA standard P54-440.
Power cables will be sized to account· for voltage drop as
follows:
Feeders between station service and MCC's -2% drop
Feeders between MCC's and final load -3% drop
total 5% drop max.
Calculations will be performed as required or tables fol-
lowed to assure the criteria is met. Voltage drop is a
secondary consideration on sizing after the NEC criteria is
met.
2-2
[15800, Section 2, EDC, 06/28/88]
00696B-1580072-Dl
*
Design loads will be based on actual nameplates of equipment
specified whenever possible. Motor currents will be based
on Article 430 tables.
The general procedures for sizing cables are as follows:
• Determine the maximum current for the load served.
This includes intermittent and continuous duty loads.
• Multiply this current by appropriate factors such as
service factor, overload factor, etc.
• Apply proper derating factors for installation configu-
ration and ambient temperatures.
• Determine cable size from appropriate tables.
• Check voltage drop to be within limits.
• Check short circuit currents.
• Determine protective device setting/rating.
Cables will be sized to carry the expected overcurrent
experienced during a fault, for a sufficient amount of time
to allow the protective devices to clear the fault.
Setting/ratings of overcurrent protective devices will be
based on loads not exceeding 80% of the overcurrent device
rating in. accordance with the NEC.
2.4 Installation
During installation as little· jacket as possible will be
removed when making connections within panels, boards,
terminal boxes, etc.
Cables passing through floor and wall sleeves, and entering
equipment will be sealed in accordance with the requirements
of Section 12.
2.5 Testing
Each conductor will be given a continuity test after
installation.
Each conductor will be given a 2500 volt megger test for 60
seconds followed by a DC hipot at the levels recommended by
ICEA for a field test. Afterward, the cable will be given
the same megger test again to verify that the cable sus-
tained no damage from the hipot test.
2-3
[15800, Section 2, EDC, 06/28/88]
00696B-1580072-Dl
Termination diagrams will be required of the contractor to
show which color coded conductor is to land on each particu-
lar terminal in the plant. The contractor will be required
to field verify the data on the diagrams is correct.
2-4
[15800, Section 2, EDC, 06/28/88]
006968-1580072-Dl
SECTION 3
LIGHTING SYSTEM
Section Title Page
1.0 DESCRIPTION 3-1
2.0 ENGINEERING/DESIGN CRITERIA 3-1
2.1 Applicable Codes and Standards 3-1
2.2 Lighting Systems 3-1
2.2.1 Normal A-C 3-3
2o2o2 ·Emergency D-C 3-3
2.2.3 Control Room 3-3
2.2.4 Branch Circuits and Panelboards 3-3
2.2.5 Ground Fault Protection 3-4
2.2.6 Grounding · 3-4
2.3 Components 3-4
2.3.1 Lighting Fixtures (Luminaires) 3-4
2.3.2 Transformers 3-4
2.3.3 Lighting Panelboards 3-4
2.3.4 Contactors 3-5
2.3.5 Lighting Wire 3-5
2.3.6 Outlet and Junction Boxes 3-5
2.3.7 Switches 3-5
2.3.8 Receptacles 3-5
2.4 Installation 3-6
3.0 OPERATING CONDITIONS 3-6
3.1 System Voltage Range 3-6
3.2 Safety Considerations· 3-6
Appendix I Lighting Chart 3-7
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
1.0 DESCRIPTION
The lighting system consists of lighting fixtures, trans-
formers, lighting panelboards and rela~ed wiring and
controls.
2.0 ENGINEERING/bESIGN CRITERIA
2.1 Codes and Standards
The following codes and standards will be used where appli-
cable to the manufacture, testing, installation, inspection
and operation of. the lighting systems:
OSHA Occupational Safety and Health Act Federal Register,
Vol. 37, N6. 202,
Means of Egress lighting, Exit
lighting .
Illumination
Subpart E,
Par. 1910.35 etc.
Subpart C, .
Par. 1926.56
ANSI American National Standards
Industrial Lighting
Protective Lighting
Institute
Street & Highway Lighting
Fixtures, Electrical
Panel Boards, Safety Standards
IES Illuminating Engineering Society
Levels of Illumination
Lighting Guidelines
NFPA ·National Fire Protection
Association
NEC -National Electrical Code
Wiring, Protection, Grounding,
Materials, Methods
Life Safety Code
Egress and Exit Lighting
2.2 Lighting System
IES RP7 -1979
IES RPlO
IES RP8 -1977
UL57 -1974
UL67 -1979
5th Edition
70 1984
101 -1981
The lighting systems will provide adequate illumination at
all times with power supplied from normal a-c sources, and
d-e batteries. The systems will provide adequate emergency
lighting during all operating conditions, including tran-
sients, upset conditions and the effect of the loss of
normal power, by use of batteries for emergency d-e lights.
The systems will provide, as a minimum, lighting intensities
at levels recommended by the Illuminating Engineering
3-1
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
Society. State and local regulatory agencies requirements
may modify the criteria.
Fluorescent lamps will be used for lighting of: Offices,
control room, lunch room, instrument shop, first aid room,
heating & ventilating room, locker room and bathrooms. High
intensity discharge (HID) lamps will be used for general
lighting, high-bay and medium height lighting, outdoor
security and for roadways. HID lighting will be specified
as hig~ pressure sodium type.
In the vicinity of the powerhouse, select outdoor lighting
will be controlled by a lighting contactor and a photo
element. The location of outdoor lighting fixtures, and the
level of illumination for different locations will be such
as to accommodate various tasks involved in those locations.
Standard street lighting fixtur·es with individual photo
elements will be provided in between the powerhouse and the
permanent facilities site.
The lighting in the main control room will be given special
consideration to ascertain that adequate light levels are
met. Dimmer and dimmer ballasts will be provided.
Exit and egress illumination will be provided in accordance
with current OSHA requirements for exit facilities and means
of egress. Exit signs will b~ illuminated by a-c and d-e
systems. The d-e system for these signs may consist of
local battery packs.
Lighting circuits will be loaded' to avoid overloading and
the subsequent tripping of breakers which would affect
lighting reliability. To prevent faults in one system from
· rendering another system inoperative, separate conduits will
be used to supply lighting systems derived from different
sources. (Emergency lighting circuits will. not be run in
the same raceways with normal lighting.)
The station lighting is composed of two separate systems:
1. Normal a-c lighting system supplied from the
normal power busses.
2. Emergency d-e lighting system supplied from
station d-e battery.
3-2
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
*
*
Normal a-c lighting is supplied throughout the plant while
emergency d-e lighting is confined to the following areas:
Control room
Diesel rooms
Egress routes and stairs
Substation
Parallel a-c and d-e systems will be physically and electri-
cally separated to prevent a common mode failure.
2.2.1 Normal A-C
The a-c lighting .system will be supplied from 3 phase, 3W,
480 v a-c motor control centers via a 480 delta-480 wye/277
V transformer. Separate 120/208 distribution panel circuits
will also be provided for convenience ~eceptacles and
lighting circuits.
2~2.2 Emergency D-C
The emergency d-e lighting will be supplied from the 125 v
d-e battery systems and will be used for exit and egress
lighting. All fixtures connected to the system will be
incandescent. Separate d-e circuit breaker type panelboards
will be used.
The d-e lighting system will be automatically energized when
a-c power sources are lost. D-e lighting circuits will be
run separate from normal a-c lighting circuits. To avoid
draining the station battery at times of unmanned operation,
DC emergency lighting system will turn off automatically
after 8 minu~es, unless overridden by a manual switch.
2.2.3 Control Room
General lighting will be supplied from recessed fluorescent
fixtures.
Control room will also have emergency d-e incandescent
fixtures powered from d-e buses.·. Fixtures are located to
provide adequate illumination for shutdown operation and
egress. Lamps will be PAR type.
2.2.4 Branch Circuits and Panelboards
In general, miscellaneous power loads, such as space heat-
ers, unit heaters, heat tracing, and fractional hp motors
rated 120 v will be supplied from a separate power system.
The few 120V lighting circuits within the plant will be fed
3-3
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
from miscellaneous 120V panels, and will not have a separate
panel allocated for them.
Branch circuit breakers for lighting and receptacles will
not have a continuous connected load exceeding 80 percent of
the branch circuit rating. Twenty percent spare installed
breakers will be provided at initial design stage with the
remaining panelboard space provided with connections for the
future breakers.
2.2.5 Ground Fault Protection
Branch circuits supplying receptacles in wet and conductive
areas will be required to have Ground-Fauit Circuit Inter-
rupter (GFCI) protection. GFCI circuits will have a sepa-
rate neutral wire for each circuit brought back to the
panelboard.
2.2.6 Grounding
The a-c lighting system will be solidly grounded with a
grounded neutral wire where applicable and an equipment
ground, in accordance with Article 250 of the NEC. A
metallic cable sheath, raceway, and/or conduit system, where
used, may take the place of the equipment ground.
2.3 Components
2.3.1 Lighting Fixtures (Luminaires)
Lighting fixtures will be selected to meet the quantity and
quality requirements specified in this document, as well as
the. mechanical performance that will meet installation,
operation, and maintenance conditions.
2.3.2 Transformers
General purpose, dry-type, 480-120/208 V and 480 delta-480
wye/277 V a-c three-phase lighting transformers will be
used. The transformers will have two 2+ percent full
capacity taps above and below rated primary voltage. All
transformers will conform to NEMA-ST20. Transformers will
have a 220 C insulation system and be designed and rated not
to exceed 150 C rise.
2.3.3 Lighting Panelboards
Emergency d-e lighting will be in separate circuit breaker
type panel boards. Panelboards will be of the dead front
type, minimum 100 A frame, factory assembled, -and will be in·
3-4
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
accordance with ANSI C33.38 "Panelboards, Standards for
Safety".
Circuit breakers will be of the molded case, thermal magnet-
ic type. Where spaces are designated, all connectors
necessary to mount future breakers will be furnished.
Enclosures will be NEMA Type 1 (general purpose), unless
otherwise noted. Ground-Paul t Circuit Interrupter Devices
will be used where required.
2.3.4 Contactors
Contactors will be single coil, electrically opera ted, UL
listed and rated for continuous full load. Contactors will
be Automatic Switch Company Bulletin 920 type RC or Engineer
approved equal. ·
Indoor enclosures will be NEMA 1 type with standard gray
finish.
2.3.5 Lighting Wire
Lighting and receptacle wire will be as stated in section 2
of the electrical design criteria, Insulated Wire and Cable.
High temperature fixture wire will be specified as required
by NEC.
Portable rubber cord type SJO will be used to supply fluo-
rescent fixtures, if required.
Splices and taps in the lighting wire will be made by *
insulated wire nuts. *
2.3.6 Outlet and Junction Boxes
Outlet boxes exposed to the weather will have suitable
weatherproof covers. Unless otherwise noted, receptacle,
switch, junction and light outlet boxes will be galvanized
3" deep boxes when recessed, and aluminum 2-1/8" boxes when
surface mounted.
2.3.7 Switches
Local switches for lighting circuits will be specification
grade.
2.3.8 Receptacles
Receptacles will be hospital grade, duplex, two-pole, *
three-wire, grounding type for 125 v, 20A Service.·
3-5
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
2.4 Installation
Installation of the lighting system will be in accordance
with UBC Zone 4 requirement and the latest edition of the
National Electrical Code, unless otherwise noted. The
lighting will be designed for early installation to facili-
tate the use-of portions of the permanent system during
construction.
3.0 OPERATING CONDITIONS
3.1 System Voltage Range
The a-c lighting system will be designed to operate with a
+10 percent voltage variation. The emergency d-e lighting
system will be designed to operate in a voltage range of 90
v d-e to 140 v d-e.
3.2 SAFETY CONSIDERATIONS
Lighting is provided from normal sources. Upon loss of
normal power, emergency lighting automatically operates
through local sensing and controlling equipment. The levels
of illumination listed in the lighting tables provide
greater than the minimum levels required where safety is
related to seeing conditions.
[15800, Section 3, EDC, 06/28/88]
00696C-l580072-Dl
APPENDIX I
LIGHTING CHART
The following chart shows illumination level* and type of fixture
used for lighting different locations of the Bradley Plant.
Location Foot Candles Fixtures
Bathroom & Locker Room
Battery Room
Compact Gas Insulated
Substation Building
Control Room
Diesel Generator Room
Files/Records
First Aid. Room
Generator Floor (El. 42'-0").
Heating and Ventilating Room
Instruments Shop
480V Load Center Area
Lunch Room
Machine Shop
Office/Conference Room
Oil Storage Room
Sewage Treatment Room
Telecommunication Room
Turbine Floor (El. 21'-0")
30 Fluorescent
30 High Pressure Sodium
(Enclosed & Gasketed)
50 High Pressure Sodium
100 Fluorescent/Dimmer
Incandescent d-e
35 High Pressure Sodium
Incandescent d-e
80 Fluorescent
80 Fluorescent
50 High· Pressure Sodium
20 Fluorescent
J..oo Fluorescent
30 High Pressure Sodium
3 Incandescent d-e
50 Fluorescent
80 High Pressure Sodium
or Fluorescent
100 Fluorescent
20 High Pressure Sodium
(Enclosed & Gasketed)
20 High Pressure Sodium
(Enclosed & Gasketed)
100 Fluorescent
30. High Pressure Sodium
*Illumination level is shown as the minimum foot-candles required
for a task and as average foot-candles for an area.
3-7
[15800, Section 3, EDC, 06/28/88]
00696C-1580072-Dl
Section
1.0
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.5.1
2.4.5.2
2.4.5.3
2.4.5.4
2.4.5.5
2.4.5.6
2.4.5.7
2.4.5.8
2.4.5.9
2.4.5.10
APPENDICES
A-1
A-2
A-3
A-4
SECTION 4
GROUNDING SYSTEM
Title
DESCRIPTION
Engineering/Design Criteria
Codes and Standards
Electrical Criteria
Station Grounding
System Grounding
480 Volt System
120/208 Volt System
D-C and Critical A-C Systems
Main Generator Neutral
Equipment Grounding
Structural Steel
Motors
Switchgear
Raceways
Piping and Tanks
Fence a-nd Rail
Surge Protection
Electronic Control Systems
Lighting
Miscellaneous .
Special Considerations
Testing and Verification of
Grounding System
Structural and Mechanical Criteria
Page
4-1
4-1
4-1
4-1
4-1
4-2
4-2
4-3
4-3
4-3
4-3
4-4
4-4
4-4
4-4
4-5
4-5
4-6
4-6
4-7
4-7
4-7
4-7
4-7
Table I 4-9
Grounding Details 4-10
Grounding Schematic
Related Manufacturers• Literature
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-Dl
1.0 DESCRIPTION
The grounding system consists of all equipment that.is used
to limit the potential between noncurrent-carrying parts and
ground to a safe value during all operating conditions.
Also included in the grounding system are those devices
which allow sufficient current flow to ensure positive
operation of protective devices in the event of accidental
contact of a live conductor to a noncurrent-carrying device.
2.0 ENGINEERING/DESIGN CRITERIA
2.1 Codes and Standards
The grounding and lightning. protection systems will be
designed and installed in conformance with the following
codes and standards:
National Electrical Code, 1984,
Article 250 Grounding
NFPA No. 78 Lightning Protection
Code
IEEE 80-1976 Safety in a-c Substa-
tion Grounding
2.2 Electrical Criteria
The grounding system is required to provide multiple low
impedance paths to earth and have adequate current carrying
capacity to safely carry the anticipated fault or impulse
current for a short period of time without permanently
damaging the grounding system or permitting a dangerous rise
in voltage during abnormal conditions.
Resistance of the station grounding system to remote earth
will be a maximum of one ohm.
2.3 Station Grounding
Station grounding will provide a low impedance current path
to earth and limit voltage gradients resulting in step and
touch voltages that are less than tolerable values.
The basic grounding electrodes for the station will consist
of a perimeter loop of tin covered copper conductor buried
parallel to and 3 ft. outsiqe the permanent plant fence, and
ground loops which will encircle the major buildings and the
swi tchyard area. Ground loops will be interconnected in a
4-1
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-Dl
manner such that destroying any one conductor will not
destroy system integrity.
Due to high resistivity of the soil beneath the power plant,
and the amount of hard rock present, a grounding mat of low
resistivity to ground will be designed and embedded into the
ground, away from the powerhouse. The ground mat will be
connected to the grounding conductors throughout the power-
house via Ground test stations.
All major structures, equipment and exposed metal parts
likely to become energized during fault conditions within
the plant area will be connected to the grounding system.
The grounding system will be accessible in all areas con-
taining electrical equipment. Ground connections .in the
powerhouse-will be accessible via flush mounted ground pads.
In outdoor locations, where large fault currents could cause
dangerous step and touch potentials (such as transformer
areas and switchyards) a closely spaced grid of buried
grounding conductors will be installed to limit potentials
to safe values as defined by IEEE Standard 80. Wherever
feasible, grounding conductors will be buried deep enough to
ensure contact with permanently moist earth. Where this is
not feasible, greater dependence will be placed on a well
distributed system of vertical ground rods bonded to the
grounding conductors and reaching deeper soil layers.
Where possible, permanent steel piling and piling used
during construction and left in place will be used as ground
electrodes.
2.4 System Grounding
System grounding consists of the connection of the neutral
or one of the normal current-carrying conductors of the
power system to ground, for the purpose of enhancing
overvoltage and short circuit protection. Such connections
will be used at various points and they may be connections
of no intentional impedance such as solid grounding, resis-
tance such as resistance grounding, or inductance such as
reactance grounding.
2.4.1 480 v system
The powerhouse 480 v 3-phase, 3-wire system will be
connected, ungrounded. Ground fault detection and
protection will be provided. At the dam site the main
will be 480/240 with the neutral solidly grounded.
diesel generator at the dam site will be 480/277
neutral grounded.
4-2
[15800, Section 4, EDC, 06/28/88]
006960-1580072-Dl
delta
alarm
power
The
with
* *
*
*
*
*
2.4.2 120/208 V System
The 120/208 v three-phase ·system neutral will be solidly *
grounded at the various sources of supply. The 120/240 *
system will be solidly grounded at 'the various sources of *
supply. *
2.4.3 D-C and Critical A-C Systems
The D-C and critical A-C systems will be ungrounded. Ground
tracing features will be used to detect and alarm uninten-
tional connections to ground.
2.4.4 Main Generator Neutral
The unit-connected main generator neutral will be grounded
through a high-resistance arrangement. This method consists
of ·connecting the generator neutral through the primary
winding of a distribution transformer to ground. The
transformers will be sealed, dry type, two-winding,
single-phase distribution transformers, with a primary
rating equal to the generator line-to-neutral voltage
nearest standard voltage rating, and a low voltage, high-
current resistor connected to the transformer 240 v secon-
dary winding.
2.4.5 Equipment Grounding
The equipment grounding conductors will have sufficiently
low impedance to limit the shock voltage on noncurrent-
carrying metal parts and enclosures to a ·safe value during
ground faults and conduct ample ground-fault current to
ensure fast operation of circuit protective equipment. In
addition, the equipment grounding conductors and connections
will have adequate short-time ampaci ty to conduct fault
currents likely to be imposed on them for the time required
to open circuit protective equipment without being damaged
by overheating.
All neutral grounding equipment used for systems grounding
and equipment protection will be connected to the station
grounding system with grounding conductors. All
noncurrent-carrying metallic parts which might accidentally
become energized, such as metal structures, building steel,
transformer tanks, motor frames, raceways, and switchgear
assemblies, will be connected to the grounding system.
Four separate direct connections to the station grounding
system, two of which are located on opposite sides of the
equipment will be provided for the main generator. Two
connections to the grounding system will be provided for
4-3
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-Dl
each of the main step-up transformers, station service
transformers, and auxiliary transformers. Areas along the
penstock, steel liner, spherical valve, and turbine spiral
casing will be grounded. Special attention will be given to
this equipment to ensure continuity of grounding protection
across areas coupled with insulated separations. All
miscellaneous bus supports, enclosures, etc., will be
connected to the station grounding system.
All signal receiving and transmitting equipment, including
communication system apparatus and protective relaying, will
be protected from extraneous high voltages by surge protec-
tion in accordance with manufacturers recommendations.
2.4.5.1 Structural Steel
Every other steel building column will be connected by bare
tinned copper cable directly to the station grounding
system. Column grounds will be made by compression or
bolted clamps not more than 2 ft. above the finished floor
elevations. -
See attached Grounding Details Nos. 1 through 4 for typical
station grounding system details.
2.4.5.2 Motors
Motors 25 hp and smaller will use the conduit system for
ground fault current return. When conduit is not used, a
ground conductor equal in ampacity to the phase leads will
be provided for motor frame grounding. Motors above 25 hp
will be grounded directly to the station ground grid.
Grounding procedure for motors is illustrated on Detail No.
5.
2.4.5.3 Switchgear
The ground bus in metal-clad switchgear, load centers, and
motor control centers will be connected to the station
grounding system at each end by ground cables. Switchgear,
load centers, and motor-control centers will be provided
with a fault current return path grounding conductor. Rigid
conduit or the ground cable in the cable tray will be used
for that purpose.
2.4.5.4 Raceways
Electrical equipment and all raceways will be_bonded togeth-
er to ensure electrical continuity. A ground cable (No. 4/0
AWG tinned copper) will be laid in all trays containing
power cables. The ground cable will be fastened to tray
4-4
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-D1
rungs in the same manner and at the same intervals as the
power conductors. At each end of the tray, the grounding
conductor will be bonded to the tray and the grounding
system.
At electrical equipment where conduit drops will not be used
and cable will run from the trays to the equipment, the
cable tray ground conductor will be bonded to the equipment
with a bonding jumper equal in current-carrying capacity to
the equipment phase leads.
Each duct bank containing power cables will have a bare
grounding conductor encased in concrete at the top of the
duct enclosure.
2.4.5.5 Piping and Tanks
All metallic underground piping and fixed p~p~ng of the fire
extinguishing systems will be connected to the station
grounding system. All pipe joints having nonmetallic
gaskets will be jumpered by a cable across each joint
(except dielectric couplings).
Metal tanks will be grounded by a cable connected to the
station grounding system. Tanks containing flammable
liquids will be grounded by two terminals on opposite sides
of each tank.
2.4.5.6 Fence and Rail
Fences within the station grounding system will be connected
to the grounding system. Fence posts will be connected at
intervals of approximately 50 ft. to a parallel ground
conductor buried 3 ft. outside the fence • Posts on each
side of a gate or removable fence section will be bonded
together below grade as showq on Detail No. 7. For each
permanent gate, a potential grid will be installed as shown
on Detail No. 8.
Fencing outside the station grounding system will be insu-
lated from fencing inside the station ground by insulating
sections as shown in Detail No. 9. Fence posts outside the
main ground grid and beyond the insulating sections will be
grounded at approximately 200 ft. intervals by connections
to ground rods.
Metallic fences which are located outside the main grounding
system and cross under distribution or tra~smission lines
will be grounded at or near the point of crossing and at
distances not exceeding 100 ft. on either side or the
crossing and insulated from sections of fencing beyond as
4-5
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-Dl
above. Analysis should be done by the Engineers to ensure
that this distance is adequate for the maximum point along
the fence that a downed conductor or the transmission line
could reach under the worst possible conditions.
Crane rails will be connected to ground and rail joints will
be jumpered as shown in Detail No. 10.
2.4.5.7 Surge Protection
Surge arrester grounding will provide a
connection to earth during an overvoltage,
damage of protected electrical equipment.
low impedance
thus preventing
Outdoor surge arresters will be grounded to the Station
grounding System or. by cables terminating at ground rods
driven near the arrester supports as applicable. The cable
between an arrester and ground system will be as short and
straight as possible.
Surge protection will be provided on all control and commu-
nication circuits connecting the power station to remote
locations. Within the plant, surge protection will be
provided for solid state devices which could be subjected to
direct or induced lightning strikes.
2.4.5.8 Electronic Control Systems
The following procedure will be implemented unless manufac-
turer's instructions are to the contrary.
Terminal cabinets, control panels and consoles involved with
electronic signals will require two grounding systems as
follows:
1. Safety Ground: Grounding bus is attached to
cabinet and panel structures.
2. Shield Ground: Instrument cable shielding and
instrument signal reference ground attached to
this bus which is isolated from the cabinet or
panel. All ground busses will be radially tied
together and grounded with 600V, 6AWG insula ted
ground cable per detail 13.
Detail Nos. 11, 12, and 13 illustrate the ground bus for
terminal cabinets, shielded wire terminations, and the
insulated shield ground bus test cabinet.
4-6
[15800, Section 4, EDC, 06/28/88]
006960-1580072-Dl
2.4.5.9 Lighting
All lighting circuits will be grounded in accordance with
the National Electrical Code.
2.4.5.10 Miscellaneous
Manholes will have an accessible grounding bus as shown in
Detail No.l4.
All miscellaneous items not included in this criteria will
be grounded in accordance with the National Electric Code.
2.5 Special Considerations
If required, ground rods will be employed. Where ground *
rods cannot be driven, a loop of cable will be used to *
establish a ground. The suitable rod material will be *
determined for the plant site. Wherever feasible, ground *
rods will be driven to reach permanently moist earth.
Ground cable passing through foundation walls will be sealed
permanently where necessary, to prevent seepage of water.
Where ground cable in concrete crosses expansion joints, the
cable will be wrapped with burlap and painted with asphaltum
or wrapped with polyethylene. The ground cable will be
wrapped a distance of 18 in. either side of the expansion
joint.
All grounding interconnections will be by crimp connection
or exothermic type weld.
2.6 Testing and Verification of Grounding System
A Ground test station will be designed and installed at a
convenient location in the powerhouse, to allow the station
ground mat to be isolated from the rest of the grounding
system. Continuity of the station ground mat will be
verified during construction. After construction, ground
resistance to remote earth will be measured and compared
with computed values. Should the measured value be substan-
tially higher than one ohm, proper corrective action may be
required. This test may be required at other times through-
out the life of the project.
2.7 Structural and Mechanical Criteria
Conductor and fittings will resist deterioration and fusing
under the most adverse combination of fault current magni-
tude and duration.
4-7
[15800, Section 4, EDC, 06/28/88]
006960-1580072-Dl
Each element of the system will be mechanically strong. In
locations exposed to significant physical damage, mechanical
protection will be provided for ·the grounding system.
Mechanical considerations will set a practical m1n1mum
conductor size. Cathodic protection system will be covered
under section 5 of this design criteria.
4-8
[15800, Section 4, EDC, 06/28/88]
006960-1580072-Dl
APPENDIX A-1
Table I -Equipment Grounding Cables
Service
125 V D-e Motors
*460 V A-c Motors (Above 25 hp)
Load Centers and MCCs
Medium Voltage Switchgear (Generator SWGR)
Power and Control Cable Tray
Instrument Cable Tray
Main Step-up Transformer
Normal Station Service Transformer
Auxiliary Transformers
Lighting Transformers
Structural Steel· Column
Main Generator
Segregated Phase Bus (Following mfg's
instructions)
Control and Relay Boards
Lighting Panels
Crane Rails, Fences
Tank and Pressure Vessels
**Computer and Other Electronic Control
Signal Systems
S~airways, Handrails, Gratings
(If isolated)
Surge Arresters (per pole)
Inverters
Chargers
Number
Required
1
1
2
2
2
2
2
2
2
1
1
4
6
2
1
1
1
1
1
1
1
1
1
Soft Drawn,
Class A
Stranded
Bare Copper
No. 4
No. 4/0
No. 4/0
500 MCM
No. 4/0
No. 4/0
500 MCM
No. 4/0
No. 4
No. 4
No. 4/0
500 MCM
500 MCM
No. 4/0
No. 4
No. 4/0
No. 4/0
No. 4
No. 4
No. 4/0
No. 4/0
No. 4
No. 4
*Motors 25 hp and smaller are considered grounded when connected to
metal raceway or via bonding to building steel.
*">'~Use Insulated Cable.
trolled atmosphere, the
permitted.
As this equipment will be located in a con-
use of Stranded Copper Conducter will be
4-9
[15800, Section 4, EDC, 06/28/88]
006960-1580072-01
*
* *
APPENDIX A-2
Grounding Details
Title
Ground of Structural Beams
Concrete Floor Air Transition
Typical Detail Ground Plate Installation
Typical Station Grounding System Routing
Grounding Procedure for Motors
Not Used
Typical Gate Grounding
Fence Gate Grid
Typical Fence Insulating Section
Typical Rail Grounding and Bonding
Ground Buses for Console and Terminal Cabinets
Shielded Wire Terminations
Insulated Ground Bus Test Box
Manhole Grounding
4-10
[15800, Section 4, EDC, 06/28/88]
00696D-1580072-D1
Detail No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
II
•boo • ' I . ·. . ~ .
-.
CONC~ETE PAD
OR FLOOR
''. _, .. -~·
\pAAa 1\~i-4EC c:u c.:J\~LI
. ,., .
{!JoT USED]
DETAIL \
GROUND IN(:, CLAMP·
• '. 6
~ . • V • ' · CONC. r:x:::'TE Ft . .OO R ~. • I ..... ~
• I <f I .
. I •&It
• 4 • ~ • 4
• • .. <i
•tiNNED COPPER CABLi TO"' .. \ •. 4.
STATION G~UND Ge\D
DETAIL "2.... Jo 155oo
Gf( OUNDI/'16 OF STRUCTURAL
BEA/'15
:>EIAIL I ~ DETAIL -z..
)
C.OMP~ESSION
TYPE
CONNECT10~
)
:"\ \N NED COPPE f\ ~R 'JUN D ?LATE
IN~E~T FO~ 4/0 CABLE
GROJN D c.A.BLE
IN 5LAB
FlOOi? · .. ~'
. t' .. -4 : . ~ ..
;
/
-.!0 15500
TYPICAL DETA\L
GROUND ?LATe
\NSTALLA TION
DETAIL 3
)
Ge.ADE
)
STE:.L C.QLUMN
.._..4--CDLlJMN et5ER
4/0 SA~E 1 INNED CcPP€ R
SEE DETAJ L ~
MPeESSJON
CONNEC.Tl ON (1'YP)
SEE DETAIL 3
'----WATE?PeooF
MEMB~A.NE.
/.
SW·E,~, MCC.' :=;,
JO 15500
TYPICAL SIAIION
GROUNDING SYSTEM
ROUTING
DETA\L 4.
SIRI\NDEO
1'1t.lNeD CoPPE~
FOR MOTO!i?'5 UP TO
'2.5HP (see noi:e 1)
C.ONNEC.T TO TB ---..
(T.f.B SE~tES S4.00)
CONNEC.T TO --
-G~OUND PAD
(T4-B SC:~It=s S400)
S1RP..NDEO
IINNED C.OPPE~
R \ ~ \0 i"\ E 11\\.
CONOU\1
BU~NDY C.ON~ECTO~ ("TYPE GA:<}
~l.EXIBLE. COt-JOUtT WITH
EXTRUDED JAC.KET
""OTO ~ P A.·D
G<OUNDING
JUMPE~ FOR
MOTORS o....,.~___,.-1\NNED COP?ER 6ND
LARGER Pl.A T2. IN5Ee-T(SEE DE.T.A.IL 3)
11-tAN ZSH P 1----'---~ ~-----------L_..:....----.1
NOTE~
1. fLEK!BLE CONDUIT MAY BE USED AS G-ROU~DtNG-coNOV'T~R
AS ALLOWED BY J/EC ARTICLE 250-'11
JO 15500
G~OUN~I Nb ?RCC.c DU \2.E
FOR MOTO e"S
DETAIL 5
)
)
GATE.
4-/0 llNNED
Co?t>ER
,, ... ;, '\. ', .· ';_·"·
GATE
GeQUND POD
JO \5500
7YPICAL GA 72
GROUNDIN6
DEIAIL 7
-~-,-~--~--·-__ .,.._ ~ ~-
-.
)
-----w--~~----~~----------~~=---~~---
..
FENCE
NOTE~
. -..
------
G£1 D 1=0~ DRrvE. GATE '5
I 3'-~ BEYOt-.10 FA~THE.S T
1 sw1N6 oF uATe :..--_._ __ _. I J-v ~--------~~--~----~·
. ?=-~
/
3'·0" f I SEE. DETAIL~,
~~~lf--JJ-..:.~--
--_..-FENC.E PE~i METER
------a--:..,__..:::..4----~---------<~~~-· · . G~·Oll N P ·
.~
..__--"'--COM r::i;! S-: SIC N.
C.CNNECIOR
!.WHEN THE Dte.EC.T\01'-1 OF C:ATE SWtN~ IS TQ
11-\E "U-lSi'()~OF me STAT10N FENC~, PLAC.E
THE ~R' \::> ON THE lt-lSt DE. W'"'EN rne GATE
'SV'ItNG IS faOni l'O llH~ lNSI DE jOUTS\t>E
.PlACE \HE GR\ t> ON BOlt\ THE INS\ t>~·
• OUTSIDE OF THE FE.Nc..E..
.IO. 15500
· FENC.E GATE 6.RtD
DE.TAlL 8
)
, ..
)
---· - -·-
)
-~ II 'Y/ ;(il/j
JO 15500
TY?ICAL r~NCF
INSULATING SEC.TICN
DETAIL '?
.)
I 'COL1 1'\NI\!C.D C.OPPE.'IZ
COMP~ESSlON. U)~ lo RI'\\L USj~~
STEEL BOLT TIN OR CADHIUH Pt.ATcD STeFL · ' FLAT WASHEJ?, BELLEVILLE TYPE COMPRESSION
WASH£R A.ND NUT..
\IN.l\lE.D copPe-.~ Cl\6\..e.
~ RoU\.10 q~\D (SOT\-\ ENDS of
CRI\t-tE: ~f\\L)
JO 15500
CRANe RAIL BOND
ANO GROUNDING
DETAIL 10
) 8.E.C.TRONIC. CABINET (INC.LUDI NG' ~E?AKATE
TO G-ROcJNO
TESTBOX ~--~
JUMPEK --4-----~+-~~
BETWEeN
SHlPPIN&
SE.PA.gA TlOt-.1
-· SHIPPING SEPARAT\ON
· TC~MINAI\ON. CAB.)
SIGNAL~ SHIELD
G~UNP BUS
(INSULA Tc: D
. ROM CABINET} ,. .
4 X \• C.OPPE~ BAK'
~A~ G,~UN D BUS
A1T A.CHE D TO C.AB lt-tET
Z11
X 1• COPPER BA~
JO 15500
G~OUND BUSES FOR
CONSOLE~ 7=:RMINAL
CABINe •:S
DETt-lL II
~ '----r--:~---------1' INSULA. TED · ~J-------1 I -~GROUND 3U5
( 1.)--CDMPeE5~10N LUG 1 --~ -
U eDLTED TO BUS
NO 1'2.
INSULATED
WI~E.
,__....,~TE~~It-JAL BLOC.~ LOCAIED IN
· TE~MINAL CA&INET 0~
/--~~~-~~~----------~
C.ONnOL CONSOLE
. 10 INST~UMEN~
IN EL:C.TRONlC.
CABlNElS OR -
I
~ ,......._. D~IN WI~E. Cc.O\/E~
WITH INSULATION)
J
ON CONTROL --~:---;_ ____ _J
C.ONSOLE.
) .
0 0
CUi TO ~· -l TAPE
De.AIN Wl~E. Ot-J ,~
___ THI5 END ONLY ___ .. ......,.l
CONTACT OUT?U1'~ ...,...--+--~..._.-SHI-~~~--~D \NSTRUM~~T
~s~~~ ~m~roL~B~
(SEE NOTE.\) ,----~----;...--...__,(SEE NOTE "Z.)
'RAN5MiiTE~ :0~ ----t~
INITIATING, -
~E\JICE. ( NO
INTE"KNAL GROUND)
( '5 EE. 1--JO TE '2.)
NOTES:
. ~ ..
......., __ C.UT iO 3,.~\A?E.
DeAIN WI~E ON
7HIS END ONLY
\. D(;!AIN 'Nl gE ON CONTAC.T OUTPUT CABLE TO BE
SOUDLY 6~0UNDEt> Ai DES'T\~ATIDN
2.. IN"TE.RMED'A rE JUNCT\0~ BO'(E-5 BETWEEN --
--·u·JITlAilNG DE:.VlC£ f CABlNET I'B ARE UNE~C.EPIABLE. --
3. 'Sc?A~AIC:. SHIELDS A~E 'TO BE CA~i:IED TH~U ---~
SECDN DA~Y-YENETgA TIONS
JO )4 SoC>
SHIELD E. D WI ~E
TE.~ M I NA'T\ 0 1-JS
DE:TAIL rz_
)
I
I
REMO\/A~LE BOLTED _ __,
. C.O~i-JEC. TIO.N :..
oUR.NDY TYPE YA
. OR. EQUAL(TYP)
NOTE:
I. JUMPE~ TO BE lYSED
ONLY WHE.N C.ABlNET5
A~E ADJACENT TO
.. ~-EACH OTH E f=:
...,.-+---NO fD iNSULATED .. -
GROUND CON D"OCTO ;z.(.IYP') -···-· ·--
-J., "'":.0 ........___ ~\z.•J COPPE"g, SA R
· INSULA lEO· F~OM
lEST CABINET
}\lQ ~-INSULA TED
G~OUND C.QNDUC.TO~
TE.S T. ·cAoiN.ET
•rC.ONNE.C.T TO 5\A. I\ ON
I . G~OUND" GR.\D AT Ji . . TI·HS:POlNT _ONLY
JO 148 00
INSULA -;-;L) G.eouN D
BUS TEST cOX
pE.TA\L I~
)
EMBEDDED --_.............,
UNISTF:UT
(AS ~EQUI~ED)
\ ,v:,...., ... ·,-_.,,, l
4/0 Bf\'RE ill'iNE.O CoPPEg CABLE
PLA~
4/0 81\RE. T\NNE.O COPPER
G~UND CABLE
EMBEDDED IN
C.ONC..eETE DUC.T oAN K
t!CG~ADE.
,,_ .. , ~ ... :::',.,, .......... .,
~ -, .. Ql I" . ~., .,
• ' C> ,-:::., ·v . •
· ..
' b
b' i .
. 'l EMBEPDED I UNlSTRUT I
I
I
I
I
I
I
.l
::lr;J 4/0 T\NNEO
CASLE
+ SECTION
' .>• . , . . , . .. .
,_
--
r4 _ __,
-:;-
1
fo Bf\RE 1\NNE.O . COPPE
cA.eu:.
C.OPPER
-------
~ ~ .. -·-~----·--
~--------------------------------JO 15500
MANHOLE GiCOUNDING
DEI?-.IL I~
-.
G-ROUNO/f.JG-_ 5.C.f/E11ATIC
PLA~r: -~!?q_U~.O .
. tr.RUI : .: . . . .
---· --• -,;._ •• .i
To -SHI~LO~SCIS:·-~----~--~-·-·-··· --~ --.:
r;R.OuNO . TESI -.
... ·sr~7JotJ
APPENDIX A-3
Sr!lTION . G-ROI//1£) .1'111T
(l.../2... ro G-B o u!'f/) tit' ;es5)
I -j
I
• • • --• •w •---
~~_:;::~· .····~~~.::~3'_:~--~~------~-
-~--·---···r---·-
... ·~·
NEW.·.
NEW
1. Quick, one man installation
2. High conductivity, cast copper
connectors
3. For connecting and tapping
cross grid, loop lines, and
ground rods
4. For direct burial or concrete
imbedded systems
5. Uses hydraulic compression
tool with standard dies
" Replaces costly exothermic
welding methods.
, . Eliminates stocking of ,
graphite molds and cartridges
Grid & Ground Rod svsrem
comoression Technique
NO. 350.1
Installs in Less fhan 3 Minutes
T&B j-Th..arn.as-& Betts
~~/
=w NEW Compression Technique
l!ii Installs in Less Than 3 Minutes (
This new Compression Method replaces
Exothermic Welding· and its problems with a quick, safe,
·reliable connector· system ... at lower installed costs
Some exothermic welding disadvantages
1. It takes about 2D-30 minutes for one man to make one weld. He has to select the right
mold, clean cables of moisture and dirt, attach mold around cable, pour the charge,
fire the charge, brake the mold open, wait for cooling, and clean out-residue from mold-.
2. If there is moisture in the mold or too large a charge is used, it may force out molten
metal, a hazard to the-~nstaller . . ... -..:...----
~ __ :. ---. 3~--::f'ow9er-chCl_rges !Jalie~~a limited· shelf life, even if stored-in-tightly sealed plastic bags.
-~ -On-·a verydamp-~daycfiarges may not fire. In damp or rainy weather, all exothermic
welding must cease on a job site.
4. Explosives are hazardous to stock.
:elusive Features-.
Quick, Safe Installation
High Reliability
1. Quick, one man installation ·-
2. High conductivity, cast copper c~nnictors
3. For connecting and tapping cross grid·,::;
loop lines, and ground rods· : · · .. --4. For direct burial or clfncrete-imb1l:dde'd~ystems
5. Uses hydraulic compression tool
with standard dies
6. Replaces costly exothermic wel~ing,!.'L':thods.
7. Eliminates stocking of graphite molds
and cartridges.
•.-.,.;;•,
Compression connections equal or exceed exothermic welded connections in all
standard tests such as resistance, corrosion, fault current and freeze-thaw.
1. Installs in less than 3 minutes. 2. Ground rod connector can be used
as continual run or tap to ground rod.
lOPR-SHIE~
iW?i
KOPR/SHIELD Compound
This homogenous copper mixture assures im-
proved conductivity or ground continuity.
Doesn't run, drip or harden. Can be used
year 'round.
Cat. No. Description
~!;(
3. Grid connector can be used as a ;;)ssover connector or tap.
CP-4 Dispenser Can
CP-8 1 /2 Pint Can with Brush
CP-16-· ---·One Pint-Can-With Brush-
• CP-128 One Gallon C"n
L ------------~
( ;!
C.
--::-____ ---··
. .• . . I... . : ~-:. : i ~ ! ,. ; ) ; I ( ; : . I . ; ) : -~ ~ ~ f ~. l :_; i~·
FOR CONNECTING PERPENDICULAR RUNS
OF STRANDED COPPER CABLE AND GROUND RODS
(Can be used as an "X" or "T" connection)
Each connector is marked with cable
size accommoaated and die coded, to
facilitate a reliable connection.
Connectors are available for
1/0, 2/0, 410, 250 and 500 MCM cables to
'h. Yo. % and 1" ground rods-(Consult Factory)
MATERIAL: HIGH CONDUCTIVITY CAST COPPER
FINISH: BRIGHT
CO~.IPRF.SSIOi\
GROUND FlUSH
PL;. TE CONNECTOR
For permanent ground system
embeaded in concrete. Four tapped
holes permit cable take off to
grounding system with T&B
color keyed compression lugs.
MATERIAL HIGH CONDUCTIVITY CAST COPPER.
FINISH BRIGHT
Rt'COIIlnlended 111St~lhng tool-T BM 15
Stud
Cat. No. Wire Size Size
52090 I I to 210 . ..
Stud
Centers
I"
·····-·--·~ ---·-····-·-· 52092 410 to 250 .. I" .. ··-·------· 52094 500 ... .. I'·• ..
Die No.
66
87H
!ISH
C•ble Size Over Jill
(AWG or MCM) lnsiJ~Ifing Die Dim.
C.t. No. MJiin Top Tool Cal. No. Code l
53050 2-1 2-1 TBMI5 15511° 54H 2'.',
53055 110-210 110-210 TBMI5 15534° 66 3
53060 4/0-250 110-210 TBMI5 15506• 87H 3\'.·
53065 4/0-250 4/0-250 TBM15 15506• 87H 3·-~· ..
15603• 53075 500 4/0-250 TBM15 15506• 125H-87H 3 14
53080 500 500 TBM15 15603 125H 3'1..
53082 750 4/0-250 21940 11427 150H-87 3'4 11423
53084 750 500. 21940 11427 150H 4'1•
53086 750 750 21940 11427 150H 4'!.
53088 1000 4/0-250 21940 11442 160-87 3!;. . 11423
53090 1000 500 21940 11442 160 4'!.
53092 1000 750 21940 11442 160 4'4
53094 1000 1000 21940 11442 160 4 14
*USE WITH CAT. NO. 15500 ADAPTER. NOTE: "H" SUFFIX ON DIE
DENOTES TWO (2) COMPRESSIONS PER CABLE.
Grounding grids are necessary wherever large amounts ol electrical current are used
or distributed includmg utility generatmg and substations. heavy industrial installations
such as refineries. chemical plants and steel mills.
The below listed cable ranges ofT &8 Gnd Connectors also accom-
modate the Copperweld Conductor s1zes:
Cable Size Copperweld Conductor Size
2. 1 AWG 3 #6
1/0.210 AWG 3/8 (7 118) or 7/16 (7 117)
4/0,250 MCM 9/16 (19 #9) or (7 #5)
500 MCM 13116 (19 #6)
•Reg. TM Copperweld Steel Co.
OTHFR ROO CONNECTORS ,\','";,_.::!LE
CONSULT FACTORY FOR SIZES AND AVAILABILITY
Two Cables To Ground Rod 31•nd End Rod Connector
Section
1.0
2.0
3.0
2.1
2.2
2.3
3.1
3.2
SECTION 5
CATHODIC PROTECTION
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes and Standards
System Characteristics
Operation
MAINTENANCE
Preventive Maintenance
Testing and Surveillance
[15800, Section 5, EDC, 06/28/88]
00696E-1580072-Dl
Page
5-l
5-l
5-1
5-l
5-2
5-2
5-2-
5-2
1.0 DESCRIPTION
Cathodic protection will be used as a means of arresting
corrosion where appropriate and feasible. It is used on
concrete and/or metallic structures which are in contact
with electrolytes such as soil or water.
Cathodic protection operates by passing direct current
continuously from anodes which are installed in the
electrolyte to the structure to be protected. Corrosion is
arrested when the current is of sufficient magnitude and is
properly distributed.
2.0 ENGINEERING/DESIGN CRITERIA
2.1 Applicable Codes and Standards
The cathodic protection systems will comply with the follow-
ing codes .and standards:
National Association of
Corrosion Engineers
Associated Research Inc.
National Electrical Code
RP-01-69 "Control of External
Corrosion on Under-
ground or Submerged
Metallic Standard
Piping Systems"
Man. 21076, "Earth Resistivity
Tests with Four
Point Vibroground"
NFPA-70,1984
2.2 Systems Characteristics
Cathodic protection . systems will be designed to provide
reliable corrosion mitigation to structures as ~equi~ed. A
through· analysis of potential corrosion problems will be
analyzed based on known parameters. Additional field data
may be gathered and. tests made when required. Specifiq
designs will be recommended and · specified to arrest
corrosion.
Station structures which will be. cathodically protected
include, but are not limited to, the concrete powerhouse,
ground mat, penstock, manifolds,and liners, underground
pipelines and tanks, water storage, tanks, sheet steel
pilings, water treatment equipment, water control gates,
trash racks and screens, and other structures and facilities
deemed necessary.
5-l
[15800, Section 5, EDC, 06/28/88]
00696E-1580072-Dl
As design and construction of the power plant continues,
cathodic protection systems will be added, modified, or
revised, as required to suit conditions.
Where an impressed current cathodic protection system using
anodes placed remote from the plant is considered, all
underground pipelines and structures will be electrically
connected to the grounding system.
All pipeline mechanical joints, ·using either rubber or
plastic gaskets, will be provided with a continuity bond.
This includes all ductile and cast ironbell and . spigot·
piping.
2.3 Operation
Each cathodic protection system will be energized as soon as
it is 6perational.
3.0 MAINTENANCE
3.1 Preventive Maintenance
A complete schedule of the manufacturer's recommended
preventive maintenance program, with supplemental recommen-
dations as deemed necessary by Stone & Webster will be
provided. Specific details and procedures unique to the
equipment will be detailed to assure proper preventive
maintenance is performed during construction.
3.2 Testing and Surveillance
The design of the cathodic protection systems will permit
routine testing and inspection. Degradation of any cathodic
protection s.ystem which will be operated continuously will
be readily identifiable and correctable.
After each cathodic protection system is energized, a survey
will be conducted to determine if it satisfies applicable
codes and standards and operates efficiently.
Test stations will be provided when deemed necessary for
determining if each cathodic protection system is in contin-
uous operation and for monitoring the effectiveness of each
cathodic protection system.
Testing and inspection duri~g construction will take place
at the intervals according to the -following schedule.
5-2
[15800; Section 5, EDC, 06/28/88]
00696E-1580072-Dl
Every two months:
All sources of impressed current will be inspected.
Reverse current switches, diodes, and interference
bonds will be tested for proper functioning.
Every six months:
Anode currents will be measured.
Yearly:
Surveys of each cathodic protection system will be
conducted to determine whether protection is adequate
·and that all components of the system are operated
effectively.
5-3
[15800, Section 5, EDC, 06/28/88]
00696E-1580072-Dl
Section
1.0
2.0
2.1
2.2
2.4
2.2.1
2.2.2
2.2.3
2.2.4
SECTION 6
COMMUNICATION SYSTEMS
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes
Design Parameters
Performance Characteristics
Page Party/Public Address System
Sound Powered Telephone System
Private Automatic Exchange
Special Requirements
[15800, Section 6, EDC, 06/29/88]
00696F-1580072-D1
Page
6-1
6-1
6-1
6-1
6-1
6-1
6-2
6-3
6-3
COMMUN_ICA,TION SYSTEMS
1.0 DESCRIPTION
The communication systems will consist of
party/public address system, a sound powered
system, and a private automatic exchange system.
offsite communications will be provided by a
system.
2.0 ENGINEERING/DESIGN CRITERIA AND PARAMETERS
2.1 Applicable Codes
a page
telephone
Plant to
microwave
The communication systems will comply with the National
Electrical Code (1984).
2.2 Design Parameters
2.2.1 Performance Characteristics
The communication systems will provide reliable communica-
tions between all areas of the station and between remote
locations and the station.
The communication systems will provide satisfactory voice
communication in noisy surroundings up to .120db, in hot
conditions up to 70°C, cold conditions down to -30°C, humid
and dusty conditio~s, and under constant vibration.
Most cables are to be independent from those of other
systems and other sources of line noise that could adversely
affect the audibility ·of the systems. All communications
wiring will be routed in rigid or intermediate metal con-
duit, underground duct, or cable ·tray. Conduit location,
method of support, and best routing will be determined in
the field.
2.2.2 Page Party/Public Address System
The Page Party/Public Address (PP/PA) system will provide *
voice communication in the powerhouse and substation and *
will be an integral part of the telephone system. *
The output of speakers in a given area normally will exceed
ambient noise by 2ldb or more within the audible frequency
range of 80 to 15,000Hz.
The PP/PA system will provide single channel party capabili-
ty as well as a public address page channel. All equipment
6-1
[15800, Section 6, EDC, 06/29/88]
00696F-1580072-Dl
will be solid state and will include handset stations, unit
speaker amplifiers, loudspeaker stations, cables, terminal
boxes, muting facilities, and connectors as required.
All wiring between components of the PP/PA system wil~ be
unshielded.
Rated output of unit loudspeaker amplifiers will not be less
than 12W. The output transformers of loudspeaker amplifiers
will have taps for 8 and 16 ohms. Circuits will remain
stable throughout the range of commercial tolerances of
replacement components and with supply voltage variations of
10 percent.
Each handset station will include a handset, a hook switch,
and self-coiling tord. The handsets will include a magnetic
receiver and a low impedance noise canceling transmitter.
Top-of-the-desk type handsets will include a small built-in
speaker and have a readily accessible speaker volume
control.
In general, all wall mounted PP/PA handsets and speaker
amplifiers will be installed 4 ft 6 in above the floor. The
speakers will be mounted on convenient structures sui table
for support, approximately 10 ft above the floor.
2.2.3 Sound Powered Telephone ~ystem
The Sound Powered Telephone system will be installed
throughout the plant to provide communication for testing,
maintenance, construction, and start-up.
A four channel sound· powered telephone system will be *
provided at the powerhouse, consisting of conduit, cable, *
· jack boxes, and headsets. A two channel · sound powered *
telephone system will be provided at the dam site equipment *
houses. Headsets will consist of earphones, microphone, *
extension cord, and plug-in jack. Headsets will be designed *
to be worn with or without hardhats. *
The system will obtain its power from the user's voice
energy at the individual headset and will not be dependent
on any station electrical system.
Jack boxes will be conveniently located throughout the
powerhouse. Each jack box will have a jack for each chan-
nel. The jacks for each channel will be connected in
parallel by a No. 18 AWG twisted pair cable. The sound
powered system cable will have an overall shield.
6-2
[15800, Section 6, EDC, 06/29/88]
00696F-1580072-Dl
2.2.4 Private Automatic Exchange
The Private Automatic Exchange (PAX) system will provide
telephone communications between areas that are frequently
manned, and the outside commercial telephone system.
The PAX will consist of telephones and a switchboard. The
switchboard will provide communications between the tele-*
phones in the network and outside lines. Telephones will be *
located throughout the plant with capability for more. *
Three outside lines will be provided. The PAX system will *
interface with the offsite telephone system via the client
provided microwave system.
Telephone auxiliary services such as pick-up and conference
calling will be provided by the client.
2.4 Special Requirements
To avoid power reduction in the PP/PA system, the cable
distance between amplifier and speaker will be kept to a
minimum. If unusual conditions dictate, the following
guides will be used.
Distance Between Amplifier and
Wire Size 8 ohm SEeaker
#18 AWG 75 ft
#16 AWG 120 ft'
#14 AWG 200 ft
6-3
[15800, Section 6, EDC, 06/29/88]
00696F-1580072-D1
Speaker (maximum)
16 ohm SEeaker
150 ft
240 ft
400 ft
Section
1.0
2.0
2.1
2.2
2 .1.1
2.1.2
2 .1. 3
2.1.4
2.1.5
2 .1. 6
2 .1. 7
2 .1. 8
2 .1. 9
2 .1.10
2 .1.11
2. 2. 2
2.2.3
2. 2. 4
SECTION 7
METERING AND RELAYING
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Operating Characteristics -
Protective Relaying
Generator Protective Relaying
13.8kV Bus Protection
Transformer Protective Relaying
Substation Bus Relaying
Transmission Line Relaying
Substation Breaker Failure
Station Service Transformers
Project Facilities Transformers
Station Service Relaying
Project Facilities Feeder
Diesel Generator
Metering Characteristics
Accuracy
Meters
Metering Table
[15800, Section 7, EDC, 06/29/88]
00696G-1580072-D1
Page
7-1
7-1
7-1
7-1
·7-2
7-2
7-3
7-3
7-3
7-4
7-4
7-4
7-4
7-5
7-5
7-5
7-5
7-6
1.0 DESCRIPTION
Protective relaying consists of devices used to monitor
equipment and systems for abnormal operating conditions.
These devices will operate at a pre-set limit to disconnect
the piece of equipment or system from the energy source to
prevent or minimize damage. ·
All. major electrical equipment will be protected by relay-
ing. Major equipment includes generators, transformers,
transmission lines, the ll5kV substation, switchgear and
motor control assemblies.
Metering, for the purposes of this
watthour and varhour meters. The
criteria describes the necessary
(volts, watts, amps etc.) that are
station.
2.0 ENGINEERING/DESIGN CRITERIA
criteria, consists of
control system design
instrumentation meters
provided throughout the
2.1 Operating Characteristics -Protective Relaying
2.1.1 Generator Protective Relaying
The generators will be continously monitored by protective
relays to ensure th~t damage incurred from short circuits or
external influences is held to an absolute minimum.
Main Unit Generator Protective Relays:
87G -Generator Differential
64NG -Generator Neutral Ground Current
40G -Generator Loss of Field 2 46G -Generator Negative Sequence (I T)
49G -Stator Overtempeiature/Overcu~rent Relay
59/BlG -Generator Overvoltage (volts per hertz)
60AG, 60BG -Blown voltage transforme.r fuse relays
51VG -Voltage restrained overcurrent
32 -Reverse Power Relay
Static Exciter Protective relays:
46 -Exciter Transformer Blown Fuse Protection
51E -Exciter Transformer Overcurrent
59F -Generator Field Overvoltage
27PS -Thyristor Power Supply Failure
58 -Power Rectifier Failure (annunciate only)
Generator Breaker Failure
7-1
[15800, Section 7, EDC, 06/29/88]
00696G-1580072-Dl
On issue of a trip signal, a timer will be started and if
the breaker is not opened within a fixed delay, lockout
relay 86BF will be operated causing backup tripping.
Shutdown devices:
86G, 86GB, 86E -Generator and exciter lockout relays;
trip generator breaker, exciter/regulator and generator
field breaker; initiates turbine shutdown; causes
immediate load rejection
86M -Generator lockout relay; initiates non-overspeed
turbine shutdown; used when full load rejection is not
necessary or desirable.
65SNL-Governor speed-no-load solenoid, (also known as
partial shutdown device) operates on transformer or
generator overtemperatures to remove load from machine
until temperatures return to within limits. operated
initially on startup until generator is connected to
power system.
2.1.2 13.8kV Bus Protection
Protective Relays:
64NG -Generator Ground Relay (listed above)
64GB -Bus Ground Relay (also backs up main generator
ground relay)
NOTE: Appropriate time delays must be added to provide
selective tripping.
Tripping Devices:
86T -Transformer lockout relay
2.1.3 Transformer Protective Relaying
Protective Relays:
NOTE:
63T -Transformer Sudden Pressure Relay
87T Transformer Differential Relay with Harmonic
Restraints
51N -Transformer Neutral Time Overcurrent Relay
Device 51N time dial to be coordinated with
transmission line ground relays so the line relays
will be allowed to clear first.
7-2
[15800, Section 7, EDC, 06/29/88]
00696G-1580072-Dl
Tripping devices:
86T-Transformer Lockout Relay; clears all possible
sources of power from transformer.
2.1.4 Substation Bus Relaying
Protective Relays:
87B -High Impedance Bus Differential Relay ( 2 zones
required)
Tripping Devices:
86B -Bus Lockout Relay; clears all possible sources of
power from fault
2.1.5 Transmission Line Relaying
High speed transmission line relaying is required to accom-
plish 6 cycle clearing times. The relays below are indicat-
ed for use on a permissive overreaching transfer trip
scheme. Actual relays purchased and the final scheme wi 11
be subject to coordination with the connecting utility.
Protective Relays:
50F -Fault Detector
21Zl -Zone 1 Distance Relay
21Z2 Zone 2 Distance Relay
21Z3 -Zone 3 Distance Relay
21TZ -Zone Timer for Zones 2 and 3
85TT -Transfer Trip Auxiliary Relay
67PG -Transfer Trip Permissive Ground Relay
67G -Backup Ground Relay
79L -Reclosing Relay
94L -Tripping Relay
Tripping: Device 94L will initiate tripping of the appro-
priate pair of breakers in the ring bus to clear a fault on
the transmission line. It will also initiate the reclosing
cycle when appropriate. Reclosing requirements . will be
coordinated with the connecting utility.
2.1.6 Substation Breaker Failure
A standard scheme of backup tripping via fault detectors and
timers will be provided. Direct transfer trip of remote
breakers will be performed where required.
7-3
[15800, Section 7, EDC, 06/29/88]
00696G-1580072-Dl
2.1.7 Station Service Transformers
Protective Relays:
50/51 -Time Overcurrent Relay With Instantaneous Unit
51 -Backup Time Overcurrent Relay
Tripping Devices:
86US1 -Trips 13.8 kV Feeder Breaker on
Device 50/51
86US2 -Trips 13.8 kV Feeder Breaker on
Device 50/51
86T -Ma.in Unit Transformer Lockout;
Backup 51 Relays
2.1.8 Project Facilities Transformers
Protective Relays:
Operation of
Operation of
Operated by
50/51 -Time Overcurrent Relay With Instantaneous Unit
51 -Backup Time Overcurrent Relay
Tripping Devices:
86 -Trips 13.8 kV Feeder Breakers On Operation of
Device 50/51 for Either Feeder
86T Main Unit Transformer Lockout; Operated by
Backup 51 Relays
2.1.9 Station Service Relaying
Protective Relays:
64S -Ungrounded 480 volt bus ground relay (Annunciate
only)
Tripping devices:
Static Trip Elements on 480 volt breakers
Shunt Trip Devices for Load Shedding
2.1.10 Project Facilities Feeder
Protective Relays:
None
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00696G-1580072-Dl
Tripping Devices:
Fuses coordinated against downstream loads
Interruption Requirements from Short Circuit Studies
2.1.11 Diesel Generator
Protective Relays:
SlV/EG -Voltage Restrained Overcurrent
32EG -Reverse Power Relay
Electric Feeder Breaker Static Tr~p Unit
Tripping Devices:
86EG -Trips Elect~ric Operated Breaker on Station
Service
NOTE: Run to destruction in fire fighting mode.
2.2 Metering
2.2.1 Metering Characteristics
Metering will be provided to rnoni tor the flow and use of
power throughout the power station. This will include the
transmission lines, the ·generators, the station service
transformers, and the project facilities transformer.
2.2.2 ACCURACY
Meters and instrument transformers on the transmission lines
will be suitable for utility grade revenue accuracy meter-
ing. In and Out watthour and varhour revenue metering will
be provided complete with magnetic-tape recording devices
for each transmission line. Meters and instrument trans-
formers for the remainder of the project facilities will be
of a grade suitable for statistical metering.
2.2.3 Meters
All watthour and varhour meters will be provided with the
following:
Pulse Accumulator Contacts for Input to Digital Comput-
er Systems
Primary Reading Registars
Drawout Cases for ease of Calibration.
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00696G-1580072-Dl
2.2.4 Metering Table
WATTHOURS WATT HOURS
LOAD IN
GENERATORS X
STATION SERVICE
PROJECT FACILITIES
TRANSMISSION LINES X
7-6
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00696G-1580072-Dl
OUT
X
X
X
X
VARHOUR VARHOURS
IN OUT
X X
Section
1.0
2.0
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
SECTION 8
CRITICAL AC SYSTEM
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes
Design Parameters
Performance Characteristics
Static Inverter
Regulating Transformer
Distribution Panel
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00696H-1580072-Dl
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8-2
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8-3
CRITICAL AC SYSTEM
1.0 DESCRIPTION
The critical AC system consists of the vital AC bus, an
inverter, a regulating transformer, and the distribution
system to critical AC loads.
"
The 120 V AC vital bus system will constitute a very reli-
able electrical system with independent conveJ:"sion equip-
ment. This system will provide a stable instrument power
supply to critical equipment and will guarantee supply to
this equipment.
2.0 ENGINEERING/DESIGN CRITERIA AND PARAMETERS
2.1 Applicable Codes
The vital AC power system will be designed and constructed
in accordance with the following codes and standards:
ANSI C57
American National Standards Institute
Transformer, Regulators, and
Reactors
National Electrical Manufacturer's Association
NEMA .AB-1-1975 (Rl981) Molded Case Circuit Breakers
NEMA FUl 1978 Low-Voltage Cartridge Fuses
NEMA res 1978 Industrial Controls and Systems
NEMA PB-1 1977 Panelboards
NEMA TR-1 1980 Transformers, Regulators,
Reactors
NEMA WC5-1973 (Rl979) Thermoplastic Insulated
and Cable
Miscellaneous
NFPA No. 70 1984 National Electrical Code
NFPA No. 78 1980 Lightning Protection. Code
8-1
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00696H-1580072-Dl
and
Wire
UL 96A 1982
2.2 Design Parameters
Installation Requirements for
Master Labeled Lightning Protec-
tion Systems
2.2.1 Performance Characteristics
The critical AC system will provide continuous, regulated,
and reliable single phase, 120 V, 60 Hz AC. control and
instrumentation power. to critical instrumentation and
protection circuits du~ing all modes of plant _operation.
The 120 V AC vital bus will be maintained at 120 +2.4 V.
When the vi tal bus is fed from the inverter source the
system frequency will be maintained at 60 +0.3 Hz. Voltage
on the 120 V AC vital bus will be continuously monitored and
displayed in the control room.
The bus will be fed primarily from a 125 V battery and
battery charger through a static inverter, or from a 480 V
bus through a regulating transformer when the inverter is
out of service. The 120 V AC and 125 V DC systems are shown
on the 125 V DC and 120 V AC vital bus one-line diagrams.
The power source for the vital bus inverter will be through
a static type battery charger supplied from a 480 V bus.
Should this power source fail, the vital bus static inverter
will be automatically powered from the batteries, which will
have been float-charged by the battery charger.. The battery
charger will meet the requirements specified in Section 10
of electrical design criteria, D.C. Systems.
2.2.2 Static Inverter
The static inverter will be suitable for input voltage range
of 101 V to 140 V DC, and output voltage maintained at 120 V
+2 percent from no load to full load. Harmonic distortion
of output voltage will not exceed 5 percent, and its fre-
quency will be maintained to within +0.3 Hz over the full
range of load and input voltage •. -The inverter will be
current limiting at 200 percent of full load and will permit
indefinite operation at that level. Upon sudden application
or removal of -full load, output voltage undershoot or
overshoot will be corrected to a level that will not cause
damage or improper operation of the inverter. In addition,
voltage will recover to within 2 percent of steady state
within 0.1 sec after the occurrence of this event. The
inverter circuitry will withstand DC input transients of up
to 4, 000 V for 10 microseconds. Specifications for the
inverter will state the above requirements.
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00696H-1580072-Dl
The output of the static inverter will be connected to a
vi tal bus distribution cabinet through a normally closed
circuit breaker.· The regulating transformer will supply an
AC input to the 120 V AC vi tal bus when the associated
inverter is down for maintenance.
The inverters will operate in continuous synchronization
with a 60 Hz, 480 V AC sine wave reference power system.
The yearly average ambient temperature of· the area where the
static inverters are located will be maintained at less than
90 F.
2.2.3 Regulating Transformer
The voltage regulating transformer will be suitable for
input voltage range of 385 to 520 V, AC, single phase, 60
Hz, +3 Hz and output voltage maintained at 120 V +1 percent
from-no load to full load with output adjustability of +10
percent. Harmonic distortion of output voltage will not
exceed 5 percent. The regulating transformer will have
current capability to withstand high in-rush load currents
and momentary overloads. Specifications for the transform-
ers should include the above requirements.
A manually operated by-pass switch is provided to connect
the regulating transformer to the critical AC bus distribu-
tion cabinet. When this switch is in the alternate or
bypass position, the condition is alarmed.
The yearly average ambient temperature of the area where the
regulating transformers are located will be maintained at
less than 90 F.
2.2.4 Distribution Panel
The distribution cabinets for the 120 V critical AC bus
system will have 15 and 20 ampere branch circuit breakers to
fire protection and other instrument loads.
The distribution panel will be supplied with' two-pole
disconnecting type fuses sui table for 120 V AC two-wire
service, insulated from ground. A ground detection system
will be provided to detect when either of the two busses
becomes connected to ground. Buses will be sized to contin-
uously carry rated full-load current with a maximum tempera-
ture rise of 50 C over a 40 C ambient.
The yearly average ambient temperature of the area where the
120 V AC vi tal bus distribution panel is located will be
maintained at less than 90 F.
8-3
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00696H-1580072-Dl
Section
1.0
2.0
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
SECTION 9
STATION SERVICE SYSTEM .
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes
Design Parameters
Performance Characteristics
Station Service Transformers
Station Service Switchgear
Motor Control Centers
Diesel Generator
120/240 V Buses
Motors
[15800, Section 9, EDC, 06/29/88]
00696!-1580072-Dl
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9-4
9-5
(
STATION SERVICE SYSTEM
1.0 DESCRIPTION
The station service system provides AC power to all electri-
cal equipment.
The station service system will consist of a double ended
480 V, 3 phase, 60 Hz staion service switchgear, two 13.8
kV-480 V station service transformers, motor control cen-
ters, 480 V panelboards, 120/208V distrib~tion panels, and a
standby diesel generator ... ·
2.0 ENGINEERING/DESIGN CRITERIA
2.1 Applicable:codes
The station
constructed
standards:
ANSI C37
service power
in accordance
system will be designed
with the following codes
American National Standa.rds Institute
Power Switchgear
ANSI C57.12-C57.106 Transformer, Regulators and
Reactors
Institute of Electrical and Electronics Engineers
and
and
ANSI C37.96-1976 (R1981) Guide for Induction Motor Pro-
tection
National Electrical Manufacturer's Association
NEMA AB-1-1975 (R1981) Molded Case Cir.cui t Breakers
NEMA E12-1966 (R1969) Inst~ument Transformers
NEMA FU1 1978 Low-Voltage Cartridge Fuses
NEMA ICS 1978 Industrial
NEMA PB-1 1977. Panel boards
NEMA PB-2 1978 Dead-Front
boards
NEMA SG3 1981 Low Voltage
Breakers
9-1
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00696I-1580072-D1
Contr'o1s and Systems
Distribution Switch-
Power Circuit
NEMA SG4
NEMA SGS
NEMA SGG-1974
NEMA TR-1·
NEMA MGl
NFPA No. 78
UL 96A
1975 AC . High Voltage Power Circuit
B.reaker
1981 Power Switchgear Assemblies
(Rl979) Power Switching Equipment
1980 Transformers, Regulators, and
·Reactors
1978 Motors and Generators
1980
1982
Miscellaneous
Lightning Protection Code
Installation Req~irements -for
Master Lightning Protection
Systems
2.2 Design Parameters
2.2.1 Performance Characteristics
The station service system and its components will be
designed for the expected life of the plant. .Voltage at
motor terminals will not be less than 80 percent of the
rated motor voltage during starting unless the motor is
specifically specified with a lower starting voltage. A
nominal system voltage of 480 kV, 3 phase, 60 Hz will be
provided to supply motors, 1 to 200 hp, and loads less than
or equal to, 200kW. Motors larger than 50 hp will generally
be controlled by 480 V switchgear breakers· to avoid using
larger than a size 3 starter.
A nominal system voltage of 120/208V, single phase, 60 Hz
will be provided to supply fractional horsepower motors,
less than 1 hp, and small single phase loads.
The 480 V system will be ungrounded. The 120/208V system
will have its neutral solidly grounded at the various
sources of supply.
Incoming and outgoing feeder conductors for switchgear, load
centers, and MCCs will be identified, viewed from the front,
as phase A, B, and C left to right, top to bottom, or front
to back as applicable.
Equipment will be arranged to facilitate
and uniform phasing.
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00696I-1580072-Dl
repair, removal,
2.2.2 Station Service Transformer
One station service transformer will be connected to each
main unit transformer low voltage bus via a 15kV circuit
breaker using 15kV shielded cable.
Each transformer will be dry type 13.8kV-480V, 3 phase, 60
Hz, with kVA capacity rated to carry the entir.e station
demand loads.
Transformer impedance values will be selected to satisfy the
following criteria:
2.2.3
a} Be large enough that the interrupting rating of
connected circuit breakers is not exceeded.
b) Be small enough to provide good plant voltage
regulation do~n to the 120V AC level.
c) Be small enough to successfully start large AC
motors.
Station Service Switchgear
The station service switchgear will be 600 V, arranged in
two buses. The diesel generator will be connected to busl
and bus 1 will be refered to as the essential bus. All
breakers will be of the drawout type. Each bus will be fed
by a 1600 amp, electrically operated main breaker. A 1600
Amp tie breaker will connect the buses. The tie breaker
will close on loss of voltage on either bus. Each trans-
former and breaker will be sized to handle full station
service load. The main and tie greakers will be electrical-
ly interlocked so only two of the three can be closed at a
time.
The feeder air circuit breakers will be selected to have
symmetrical interrupting rating (KA} capable of interrupting
the maximum available fault.
Feeder breakers for the Mcc•s will be manually operated at
the switchgear. The main breakers, the tie breaker, and the
breaker connecting the diesel generator to the essential bus
will be electrically operated with automatic control, local
or remote, as required. Electrically operated circuit
breakers with 125 V DC controls will be supplied.
2.2.4 Motor Control Centers
Motor control centers will be strategically located through-
out the plant. Equipment in the MCC will include
9-3
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00696I-1580072-Dl
combination starters for motors and single and three phase
molded case feeder breakers, for lighting, heating, and
other loads.
Motor control centers (MCCs) will be rated 480V, 3 phase, 60
Hz. They will utilize motor starters, and molded case
circuit breakers for motor branch circuit protection. The
motor branch circuit breakers, and those used for feeders,
will have a minimum symmetrical interrupting rating of
25,000 amps.
480-120V control power transformers will be supplied where
required.
Loss of AC power to a starter or contactor will cause it to
fail open, disconnecting the load. The 480V system will be
designed such that the voltage at· the MCCs will be within
the starter pickup voltage rating. MCC distribution and
miscellaneous feeders will be provided with manual control
at the circuit breakers. Circuits will be provided_ with
automatic or local control as required.
2.2.5 Diesel Generator
A back up diesel generator will be connected to the station
service essential bus through an electrically operated
breaker. The diesel will provide station power in the event
of loss of offsi te . power. It will also provide emergency
power for the station fire pumps and will be arranged to
meet NFPA codes.
The diesel generator will be sized to supply essential
station service loads plus the station fire pump. It will
be self-ventilated, have a class F insulation, and class B
rise at 40 C ambient. The generator will be self-contained
with its excitation, voltage regulation and control panel.
2.2.6 120/208V Buses
120/208V buses will be provided to supply miscellaneous
power· loads, such as space heaters, unit heaters, heat
tracing, and fractional hp motors rated 120V. Buses will be
located throughout the powerhouse. Each circuit will be
protected by a manually operated single-pole circuit break-
er. Where a circuit will be used with automatic or remote
control, a separately mounted motor starter or a single-pole
relay connected to the load side of the circuit breaker
will be used.
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00696I-1580072-Dl
2.2.7 Motors
All motors will be specified to develop sufficient horsepow-
er to drive the connected load under runout or maximum
expected flow.or pressure, whichever is larger, and permit
the driven equipment to develop its specified capacity
without exceeding the temperature limits of the motor.
Motors rated for more than 10 hp. will be capable of accel-
erating the connected load to full load speed with 80
percent of rated voltage at its terminals. Motors will be
specified to be NEMA design B with the equipment it drives,
except for specific service applications.
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00696I-1580072-Dl
Section
1.0
2.0
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.2.5
2.2.6
2.2.7
2.2.8
SECTION 10
DC SYSTEM
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes
Operating Characteristics
125 V DC System
Battery
Battery Racks
·Battery Chargers
Distribution System
DC Motors
Auxiliary Electrical Equipment
Battery Room
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10-4
10-4
10-4
·DC SYSTEM
1.0 DESCRIPTION
The DC power system will consist of the 125V DC station
battery and chargers, distribution panels and equipment.
2.0 ENGINEERING/DESIGN CRITERIA
The DC system will be designed for the expected life of the
plant.
2.1 Applicable Codes
The DC power system will be designed and constructed in
accordance with the following codes and standards:
American National Standards Institute
ANSI C37 Power Switchgear
Institute of Electrical and Electronics Engineers
IEEE Std. 484
IEEE Std. 450
IEEE Std. 485
1981
1980
1978
Recommended Practice for Instal-
lation of Large L-ead Storage
Batteries for Generating Stations
and Substations
Recommended Practice for Main-
tenance, Testing, Replacement of
Large Lead Storage Batteries for
Generating Stations and Sub-
stations
Recommended Practice for Sizing
Large Lead Storage Batteries for
Generating Stations and Sub-
stations
National Electrical Manufacturer's Association
NEMA AB-1-1975
NEMA FUl
NEMA PB-1
NEMA PB-1
Rl981
1978
1977
1977
Molded Case Circuit Breakers
Low-Voltage Cartridge Fuses
Industrial-Controls and Systems
Panelboards
10-1
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00696J-1580072-Dl
NEMA PB-2 1978 Dead-Front Distribution Switch-
boards
2.2 Operating Characteristics
2.2.1 125 V DC System
The 125V DC system will provide a nominal 125 V power supply
for control, relaying, emergency power and lighti.ng, and
other low voltage critical loads.
The DC system will consist of one battery connected to a
125 V DC bus supplied by the battery chargers. The system
will be operated at a normal float charge voltage level to
maintain the battery in a fully charged state. The voltage
at the terminals of the DC :electrical equipment fed from
this battery is expected to vary between 140 and 108 volts
DC.
2.2.2 Battery
The battery will be lead-acid, station type. The battery
will be sized per IEEE 485 with ampere-hour capacity
suitable for a period of eight hours, in the event of loss
of all AC power and without the use of battery chargers. At
no time during the eight hour period will the battery
terminal voltage drop below 1. 75 V per cell. The charac-
teristics of each load, the time duration each load is
required and the basis used to establish the power required
for each load will be used to establish the combined load
demand to be connected to the DC power supply during the
"worst" operating conditions.
The battery will be ·specified to withstand the design
siesmic event.
The battery will be enclosed in a separate ventilated room.
Intercell and terminal connectors
lead-plated copper connectors.
will consist of
The battery will be provided with a battery disconnect
switch for maintenance.and safety.
In order to ensure maximum battery life, the average yearly
electrolyte temperature will be maintained at 77 degrees F
or below. This temperature will not exceed 90 degrees F for
more than one percent of the yearo
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00696J-1580072-Dl
2.2.3 Battery Racks
The battery will be mounted on battery racks constructed of
steel rails, frames, and braces. The racks will be provided
with acid resistant insulated channels on which the battery
cells will rest, and noncombustible, moisture and
acid-resistant spacers between the cells to keep them
aligned. The metal surfaces of all racks will be coated
with acid-resistant enamel paint and will be solidly con-
nected to the station grounding system.
The racks will be rated to survive the design siesmic event
while carrying the battery.
2.2.4 Battery Chargers.
Each static type battery charger _will have ample capacity to
supply the steady state loads under any plant condition,
while recharging the battery to a fully charged condition
from the design minimum charged state within 8 hours~. *
Each static battery charger for the 125 V DC power system
will have a nominal output float voltage of 130 to 135 V DC,
with an input of 480-V AC, 3-phase,. and will limit the
output ripple voltage under full load without the battery
attached, to one percent rms or less.
The average ambient temperature of the area where the
battery chargers will be located, will be maintained at less
than 90 degrees F year round. However, the battery chargers
will be specified to be capable of continuous operation at
rated output current in ambient temperatures of 0 to 140
degrees F (-17.8 to 60 C), based on use of components with
adequate thermal ratings and not on increas~. in the charg-
ers• standard_ ·ventilating capacity, thus· reducing the
components• incidence of failure.
2.2.5 Distribution System
The distribution system will consist of all equipment in the
distribution circuits from the supply . devices to their
loads. Components of the system will be marked for easy
identification.
The battery will be connected to a DC distribution panel
which will supply the appropriate DC loads.
All branch circuits will have overcurrent protection on both
wires.
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00696J-1580072-Dl
The average ambient temperature of the area in which the
battery distribution panel will be located, will be
maintained at less than 90 degrees F (32.2 C) year round.
2.2.6 DC Motors
All DC motors will be rated for the 125 V DC system and will
be capable of delivering adequate power so that the driven
equipment will perform its intended function properly when
the voltage at the motor terminals varies between 140 V and
101 V DC.
2.2.7 Auxiliary Electrical Equipment
Auxiliary electrical equipment such as motor starters,
breakers, and relays used in the 125 V DC power system will
be capable ·of operating between 140 V and 101 V DC.
Motor · starters will be single-pole of. the reduced-inrush
type, using step starting resistors and timers to limit the
current to safe values during acceleration.
Motor starters will be located close to the battery ra~her
than near the motor and separate leads will be run to the
motor shunt fields. This will minimize the voltage drop
problem due to high inrush currents which· may result in
unsatisfactory starting performance because of low field
excitation levels.
2.2.8 Battery Room
A separate battery room will be provided for the battery of
the DC power systems. The room will provide a well venti-
Yated, clean, cool, and dry place so that the cells will not
be affected by sources of radiant heat such as sunshine, or
heating units.
The battery room will have a designed ambient temperature of
65+ 5 degrees F year round to provide optimum battery life,
ease of maintenance, and low cost of operation. Since
variations in electrolyte temperature between cells of more
than 5 degrees F may cause the warmer cells to become
unequal, proper battery locations, ventilation, and cell
arrangement will be provided to keep this variation within
the above limits, and prevent deterioration of the positive
plates thus prolonging battery life.
The battery room will be ventilated to maintain the design
temperature and prevent accumulation of hydrogen. The room
air will be changed at sufficient frequency to keep hydrogen
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00696J-1580072-Dl
liberated from battery cells below the maximum allowable
concentration of less than two percent by volume.
A permanent eyewash station and shower will be provided
adjacent to the battery room
The battery room will be provided with adequate aisle space
for inspection, maintenance, testing, and cell replacement.
Space will also be provided above the cells to allow for
operation of lifting equipment, and addition of water. The
battery room floor will have an acid resistant coating.
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00696J-1580072-Dl
•
Section
1.0
2.0
2.1
2.2
2.3
2.4
2.5
3.0
3.1
3.2
2.2.1
2. 2. 2
2.2.2.1
2.2.2.2
2.2.2.3
2.2.2.4
2.2.2.5
2.2.2.6
2.2.2.7
2.2.2.8
2.2.2.9
SECTION 11
SUBSTATION DESIGN
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes and Standards
Operating Characteristics
Main Power Transformers
Compact Gas Insulated Substation
Power Circuit Breakers
Gas Insulated Isolating and
Grounding Switches
Key Interlocks
Gas Insulated Bus
Bolted Covers
Current Transformers
Voltage Transformers
Air Terminals (Outdoor SF 6
Bushings)
Surge Arrestors
Equipment Protection
Installation
Testing
SPARE PARTS AND MAINTENANCE
Gas Cart
Special Tools
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11-8
11-8
11-8
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11-9
SUBSTATION DESIGN
1.0 DESCRIPTION
The substation will consist of a combination of electrical
equipment for the purpose of transforming voltage from 13.8
kV to 115 kV and safe connection of the station to the 115
kV transmission lines.
2.0 ENGINEERING/DESIGN CRITERIA
2.1 Applicable Codes and Standards
The substation and main power transformers will be designed
and constructed in accordance with the following code~ and
standards:
Institute of Electrical and Electronic Engineers (IEEE) .
IEEE P468-l/JUNE 1981
IEEE P468-2/JUNE 1981
IEEE P760/APRIL 1982
Proposed Standards, Recommended
Procedures and Guides, Gas-Insu-
lated Substations
Recommendations to Other IEEE
Committees, Gas-Insulated Sub-
Stations
Proposed Standards for Gas-
Insulated Metal Enclosed Inter-
rupter, and Grounding Switches
(ANSI C37.38 -198X)
American National Standards Institute (ANSI)
ANSI C37.04 1979
ANSI C37.06 1979
ANSI C37.09 1979
ANSI C57.12.10 1977
Rating Structure for High-Vol-
tage Circuit Breakers
Preferred Ratings and Related
Capabilities for Ac High Voltage
Circuit Breakers
Test Procedure for Ac High Vol-
tage Circuit Breakers
Requirements for Transformers
230,000 Volts and Below, 750/862
Through 60,000/80,000/100,000 KVA
Three Phase
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ANSI C57.13
ANSI C57.106
ANSIC62.1
1968
1977
1971
(R75)
Requirements
Transformers
for Instrument
Guide for Acceptance and Main-
Tenance of Insulating Oil Equip-
ment
IEEE Standard for Surge Arres-
tors for Alternating Current
Power Circuits
National Electrical Manufacturers Association (NEMA)
NEMA LAl
NEMA SG6
NEMA TRl
NEMA 107
1976
(R80)
1974
Surge Arrestors
Power Switching Equipment
1980(R83) Transformers, Regulators and
1977
(R81)
Reactors ·
Measurement of Radio Influence
Voltage (RIV) of High-Voltage
Apparatus, Methods of
American Society For Testing and Materials (ASTM)
ASTM Al23
ASTM Al53
ASTM 02472 ·
ASTM 03487
1978
1978
Zinc Coating On Fabricated
Products
. Zinc Coating (Hot Dip) on Iron
and Steel Hardware
197l(R80) Standard Specification for
Sulfur-Hexaflouride
1981 Standard Specification for
Mineral Insulating Oil Used in
Electrical Apparatus
American Institute Of Steel Construction
-1970 Manual of Steel Construction,
7th Edition
American Society of Mechanical Engineers (ASME)
ASME VIII 1983 Section VIII, Division I, Unfired
Pressure Vessels and All Addenda
Thereto
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2.2 Operating Characteristics
The substation will conve~ pow~r from the m~in units to the
transmission lines and provide protection of the trans-
mission lines and maln power transformers. It will serve
the function of disconnecting equipment from energy sources
to perform inspections and maintenance. It will provide the
necessary instrument transformers for protection of the
transmission lines and substation equipment as well as for
revenue accuracy metering of the power gener'a ted by the
station and transmitted over the transmission lines.
2.2.1 Main Power Transformers
Mineral oil insulated.power transformers capable of feeding
full power output from the two generators will be installed
adjacent to the substation. One transformer will be provid-
ed for each generator plus a spare transformer.
The transformers will be lo~ated on 25 foot centers so their
foundations can be plac~d on solid rock.
The transformers· will each
concrete enclosures with oil
and prevent spread of fire
ture. Oil from a ruptured
the dirty water sump. The
minimize resulting damage
be placed in open three sided
catch basins to contain the oil
should a transformer tank rup-
transformer tank will drain to
transformer enclosure will also
should a transformer explode.
The walls will extend to 1 foot above the top of the bushing
enclosure and wi.ll be braced at the top against seismic
activity. The wall height will be such that the seismic
bracing will not have to be removed to withdraw the trans-
formers from the enclosure.
Transformer handling will be. based on moving transformers
full of oil. Due to the spare transformer which will be
provided at the site, the need for normal transformer
draining facilities is eliminated. If it is determined
necessary to drain a transformer on site, tank trucks will
have to be brough~ in as required.
Transformers will be two winding, triple rated_ OA/FA/FA or.
OA/FA/FOA, 33.8/46.8/56.3 MVA. The transformer will have a
BIL rating of 550 kV. Primary_ val tage will be 115 kV.
Secondary voltage rating will be 13.8 kV with a no-load tap
changer for standard 2-1/2% and 5% taps above and below
rated voltage. The high voltage bushings will be SF 6 con-
denser. type for direct connection to the gas insulated
substation.
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The transformers will be specified to include a dry nitrogen
blanket above the level of the oil to exclude moistrue from
the insulating oil. Each transformer will be provided with
its own gas maintenance system · consisting of nitrogen
bottle, valves and regulators. Low pressure in either the
transformer or the nitrogen bottle will generate station
alarms
The transformer tanks will be rated for full vacuum and will
have suitable connections for vacuum filling of the insulat-
ing oil. The transformers will be built in accordance with
applicable ANSI and NEMA standards and will be. required to
pass applicable ANSI and IEEE factory tests. High voltage
and neutral bushing wells will be provided to house.standard
multi-ratio bushing current transformers. Safety and
protective devices to be included are:
• sudden pressure relay
• rupture diaphram with operation indicating ~witch
• oil level gage with switches·
• hot spot RTD and thermometer embedded in the
windings
• thermal relay for automatic cooling ·control and
alarm
Radiators will be provided with blanking valves so that the
radiators can be removed without draining the transformer
tank. Cooling fans and/or oil pumps will ·be provided to
handle peak loads through the transformer. When the thermal
relay indicates ·extreme overtemperature the turbine governor
will unload the generator until the transformer temperature
returns to normal limits.
Oil drain and sampling valves will be provided.
Mineral oil will be furnished in accordance with ASTM
standard 03487.
2.2.2 Compact Gas Insulated Substation(CGIS)
The substation will be a compact gas insulated type consist-
ing of the bus, power circuit breakers, disconnect switches,
grounding switches, current transformers, voltage trans-
formers, air terminals, and surge arrestors. The substation
will feed two separately switched 115 kV transmission lines.
The transmission lines will utilize the power house as a
dead end structure.
The substation will be designed as a four breaker ring bus
with capability for the addition of a fifth breaker to
accomadate a future third unit. Isolating switches will be
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provided to isolate each breaker from all power sources and
to isolate each substation feeder (Refer to the one-line
diagram). In case of a fault on a feeder, the two breakers
connected to that feeder will open and power will be routed
through the remaining portions· of the ring bus. If a fault
is determined to be of a permanant nature, the feeder can be
disconnected from the substation by means of its isolating
switch and the· breakers reclosed to allow maximum opera-
tional reliability.
Surge arrestors will be provided at the air terminals of the
substation external to the gas system.
The ·115 kV substation will be comprised of dead-front three
phase equipment, housed by a single enclosure. The primary
insulating media will be· sulfur hexaflo"uride gas (SFs) that
meets all requirements of ASTM standard 02472.
The substation gas system will be divided into sections by
gas barrier insulators located throughout the substation.
Each circuit breaker, disconnect switch, voltage transformer
section, current transformer group or bare run of bus will
maintain its own gas system separately from the rest of the
substation. In this way, a.single contingency failure of the
gas system would not cause an entire outage or potential
major failure of the substation. Only grounding switches
will not be contained independently.
The gas insulated bus will extend to the transformers and
directly connect to the high voltage bushings so that the
bushings are completely encl·osed. Gas barrier insulators
will be provided to allow removal of the transformers from
the substation without depleting the gas in long runs of
buswork. · ·
-
The nominal pressure of the gas will be 3. 5 atmospheres
except in the circuit breaker compartments which will be 6
atmospheres. Rupture discs and gas density relays will be
provided in each independent gas section of the substation.
Connections will be provided for filtering, circulation and
replacement of gas in eaqh section.·
The final paint for the substation will be 'a heat sensitive
type such that the paint will discolor at the point of a
fault inside the enclosure.
All structural supports, walkways, platforms, ladders, and
stairs required for operation and maintenance, or necessary
to provide a freestanding substation· will be provided as a
part of the substation. Platforms, walkways, railings, etc,
will conform to OSHA requirements.
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Instrument transformers will be provided as required by
Section 7, Metering and Relaying.
2.2.2.1 Power Circuit Breakers
Circuit breakers in -the CGIS will be rated in accordance
with ANSI C37.04 for 121 kV, 550 BIL and will have a nominal
cleating time of 3 cycles (on a 60 Hz basis). Circuit
breakers will meet or exceed all applicable parts of ANSI
. C37.06. The interrupter will be of the puffer type and will
not require dual pressure chambers. All three poles of the
circuit breaker will function simultaneously from a hydrau-
lic driving mechanism. The power supply for the hydraulic
operator will be 480 volt, 3 phase. The driving mechanism
will be capable of de-coupling from the breaker for safety
during maintenance. Testing of breakers will be in accor-
dance with ANSI C37.09. Lockable NEMA 1 enclosures will be
provided for the control and wiring cabinet.
2.2.2.2 Gas Insulated Isolating and Grounding Switches
Isolating and grounding switches will be of the non-load
break type and will be used only for isolation and static
grounding of equipment after it has been already been
de-energized by circuit breakers. Switches will meet the
requirements of IEEE P760. The switches will be capable of
carrying full rated substation current. Normal operation
will be by electric motor operators, but operation by hand
will be possible. Operation of all three poles will be
simultaneous. Enclosure windows will be_ provided for
visible-indication of electrical isolation and grounding.
Semaphore type position indicators and electrical limit
switches will also be provided. The: gas system of the
isolating switches will be separated by gas tight barriers
from adjacent sections. Grounding switches will be provided
for static safety grounding of normally energized parts for
maintenance. Grounding switches will be included within the
gas system of the component to be grounded. Suitable
electrical and key interlocks will be provided to prevent
accident~l op~ration of the isolating or grounding switches
while the connected bus is energized.
2.2.2.3 Key Interlocks
Each bay consisting of circuit breaker, disconnect switches
and ground switches will be key interlocked to prevent
accidental or improper operation of switches under load.
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2.2.2.4 Gas Insulated Bus
Gas bus will be provided between components of the substa-
tion, the main power transformers and the outside line air
terminals. The gas insulated bus will house all three-phase
conductors in a common enclosure. Expansion joints will be
provided as required. Enclosures and expansion joints will
conform to IEEE standard P468-l. Where busses are located
outdoors, electric heaters will be provided to prevent
condensation of the gas during extreme cold temperatures.
2.2.2.5 Bolted Covers
All equipment enclosures will have bolted covers so that the
equipment contained therein may be removed through the
opening without major disassembly of the substation.
2.2.2.6 Current Transformers
Toriodal type current transformers will be provided for bot.h
relaying and metering applications. They will be
multi-ratio type where applicable. All secondary leads will
be brought out to a terminal strip through a gas tight
bushing. Accuracy classes will be specified as required by
Section 7, Metering and Relaying criteria. Current trans-
formers will meet all applicable parts of ANSI C57.13.
2. 2. 2 .• 7 Voltage Transformers
Voltage transformers will meet applicable requirements of
ANSI C57 .13. Accurracy classes will be specified as re-
quired by Section 7, Metering and Relaying criteria. All of
the 115 kV voltage transformers will be gas insulated.
2.2.2.8 Air Terminals (Outdoor SF 6 Bushings)
Air terminals sui table for mounting either vertically or
horizontally will be provided for carrying the power from
the substation to the transmission lines.
2.2.2.9 Surge Arrestors
Station class surge arrestors will be provided at the air
terminals of the substation, external to the gas insulation.
Arrestors will be rated .to meet ·the . requirements of ANSI
C92.1 and NEMA LA-1.
2.3 Equipment Protection
The substation bus, transmission lines, and main power
transformers will be protected as required by Section 7,
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Metering and Relaying criteria.
2.4 Installation
Before the substation assemblies are brought to the power-
house, the substation building must be essentially completed
and serviceable. The area will be cleaned comletely and the
dust level established as minimal. After the substation
supplier has given an approval to proceed, the substation
equipment will be moved into the substation building. Every
effort will be made to keep the substation building clean
during the final assembly of the equipment. Final assembly
connections will only be made on approval of the suppliers
field erector. After all components are final assembled, a
vacuum will be drawn on the equipment to remove all mois-
ture, air and inert gases from shipment. A complete charge
of SF 6 gas will then be given to all sections of the substa-
tion and each section will be checked for leaks as required
by the proposed standards. All pieces will be assembled
final except the transformer connections which will be left
open until hipot testing is completed.
2.5 Testing
After final assembly in the field and gas pressurization,
the substation will be given first an AC hipot test, then a
DC hipot test at the levels set by the proposed standards.
for gas insulated substation. Only after completion of
these tests will the substation be considered ready for
energization from the power system. The power transformers
and the power lines will be open circuited from the substa-
tion during the hipot tests.
3.0 SPARE PARTS AND MAINTENANCE EQUIPMENT
3.1 Gas Cart
A gas cart will be provided complete with gas compressor,
vacuum pump, refrigerant cooled ASME Code storage tank,
heaters, filters, necessary controls, valves, gages liquid
level indicator and equipment required to provide for
recieving storing, filtering, drying and replacing gas for
maintenance purposes. The cart will include pressure and
vacuum hoses for connection to the gas enclosures and to gas
bottles. A power cord will also be included. The gas cart
will be sized such that it can conveniently be moved around
in the substation area.
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3.2 Special Tools
One complete set of special tools or fixtures required for
operation and maintenance will be furnished as part of the
substation. "Special" is defined as anything not normally
and/or readily available.
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Section
1.0
2.0
2.1
2.2
2.3
2.4
SECTION 12
FIRE STOPS AND SEALS
Title
DESCRIPTION
ENGINEERING/DESIGN CRITERIA
Applicable Codes and Standards
Performance Characteristics
Materials
Breaching Fire Stops
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FIRE STOPS AND SEALS
1.0 DESCRIPTION
Fire stops and seals are provided where raceways penetrate
walls, floors and equipment, and require a barrier against
smoke, dust, water or Halon. A fire stop has a fire rating
equal to the required fire rating of the barrier and a seal
does not.
2.0 ENGINEERING/DESIGN CRITERIA
2.1 Applicable Codes and Standards
There are no recognized codes or standards for fire stops
for raceway penetrations at this time.
2.2 Performance Characteristics
Normal design practice dictates that the openings ar·ound
cables passing through floor and walls be sealed.
··when cables penetrate a fire barrier the fire stop must
fulfill the following requirements:
a. Must have a fire rating proven by test.
b. Satisfy insurance company requirements.
c. Be compatible with cable insulation and jacket
material.
d. Consider derating, if any, of power cables.
e. Prevent passage of flame or. smoke for a time
interval equal to or greater than the fire rating
of the wall it penetrates.
f. Allow future addition or removal of cables and be
capable of being resealed.
When cables penetrate a non-fire rated barrier the seal must
meet the following requirements:
a. Be compatible with cable jacket material.
b. Consider derating, if any, of power cables.
c. Allow future addition or removal of cables and be
capable of being resealed
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The cable penetrations will be designed as. a system, taking
into consideration the size of the opening, depth of the
opening, type of cable insulation, and jacket, etc.
The cable will penetrate the floors and walls through round
metallic sleeves or rectangular slots.
Cable trays will not be carried through fire barrier walls,
to minimize the transfer of heat.
2.3 Materials
The following materials will be used as fire stops and seals
for raceway penetrations:
Dow Corning Silicone Foam Q3-6548
Thomas & Betts Flame Safe
2.4 Breaching Fire Stops
Fire stops which have been breached (to add or remove
cables) will be restored to their original design integrity
immediately after the work is complete. *
Fire stops will have a two-hour rating and will be provided
where bus or cable penetrate fire rated walls or floors.
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