ALASKA POWER AUTHORITY

TYEE LAKE HYDROELECTRIC PROJECT WRANGELL AND PETERSBURG, ALASKA

FERC PROJECT NO. 3015

FINAL DESIGN REPORT VOLUME 2 OF 3

MAY 1984

~ !~I.~,~"N,~!!g~~!-",ENGINEERING COMPANY, INC.

TYEE LAKE HYDROELECTRIC PROJECT FINAL DESIGN REPORT

VOLUp. I I

TRANSMISSION LINE

CONTENTS

Section Page

1 I NTRODUCTI ON 1-1

2 LONG SPAN DESIGN 2-1 2.1 Long Span Deadending 2-1 2.2 Phase Spacing Requirements 2-3 2.3 Conductor Side Swing Clearance 2-3

3 BLIND SLOUGH REALIGNMENT 3-1

4 FOUNDATION AND ANCHOR DESIGN 4-1

5 INSULATOR HARDWARE ASSEMBLIES 5-1

6 TOWER DESIGN 6-1 A. Self-Supporting Deadend Towers 6-1 B. ST3-E55 Tower Design 6-1 C. Guying Requirements 6-1 D. Tower Vibration Protection 6-2 E. Guy Yokes of STX-El0 Towers 6-3

7 LONGITUDINAL LOAD CAPABILITY 7-1

8 SHOEMAKER BAY-WRANGELL TIE LINE 8-1

9 SUBMARINE CABLES AND SUBMARINE CABLE TERMINALS 9-1

10 COMPARATIVE LISTING OF CHANGES IN DESIGN ITEMS 10-1

i

APPENDICES

Appendix

A BASIC DESIGN MANUAL REVISIONS

B LONG SPANS No Exhibit B-1 included Exhibit B-2 Failure Containment Exhibit B-3 Summary of Long Span Design Exhibit B-4 Self-Supporting TO~/er Design Criteria

Drawing 2708-TS-150 Exh'ibi t B-5 SURlTlary of Cl earance Studi es

C US FOREST SUPERVISOR's DECISION MARCH 15. 1982 (Blind Slough Realignment)

o FOUNDATION DRAWINGS Exhibit 0-1. 2708-TS-115 Exhibit D-2. 2708-TS-112 Exhibit 0-3. 2708-TS-128 Exhibit D-4. 2708-TS-131

E ANCHOR DRAWINGS Exhibit E-l. 2708-T5-138 Exhibit E-2. 2708-TS-114

F SHOEMAKER BAY-WRANGELL TIE LINE

TSF-6A TSF-7 TSF-7A TSF-8B

TA-3BR TA-4S-55

Exhibit F-1, Basic Design Manual Exhibit F-2. Right-of-Way Requirements

G BASIC DESIGN MANUAL

; i

SECTION 1 INTRODUCTION

The Basic Design Manual (BDM) for the transmission line is the centerpiece of this final design report. Some aspects of the original BOM have changed and these are presented in Appendix A, Basic Design Manual Revisions. The 80M itself is found in Appendix G.

The objective of this final design report is to document major changes made to the transmission line design in the course of the project.

The major changes include a revised design of 13 long spans over 4000' to incorporate extensive deadending and increased phase spacing; several steel tower modifications such as the design of two self-supporting deadend tower types. revision of guying requirements and tower vibration protection; foundation and anchor changes to accommodate extensive poor soil bearing capacity; the Blind Slough Realignment ilTlp1emented at the direction of the U.S. Forest Service; and, the addition of the Shoemaker Bay-Wrangell 138 kV tie line.

In addition. a synopsis of longitudinal load capacity of suspension towers and discussion of submarine cable and cable terminals are presented.

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SECTION 2 LONG SPAN DESIGN

There are 13 extra long spans on the Tyee Lake transmission line ranging from 4,000 to 8,000 feet.

2.1 LONG SPAN DEADENDING

A. Original Design

The original design at the long spans called for a predominant use of strong, guyed .-frame suspension structures with V-string insulator assemblies (see IECO Drawing 2708-TS-2 or, for instance, ITT-Meyer erection Drawing 2572, Sheet 44). This original design reflected a design philosophy that longitudinal load unbalances are better absorbed by flexible suspension strings. Judicious placement of guyed deadends and the use of guy yokes on the w -frame structures was designed to limit catastrophic failures (see Exhibit B-2).

B. Design Changes

The design was changed to provide deadending at all long spans over 4000 1 Field investigation of all long span tower sites revealed several sites whose narrow topography would not permit the use of guyed deadend towers. The deadending of the long spans was accomplished by:

o Replacing running angle 3-column towers and strong suspension towers with guyed deadend structures where site topography permi tted;

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o Retaining strong suspension towers adjacent to long spans and backing them up with deadend towers; or

o Using self-supporting tubular steel deadend towers at sites whose topography did not allow guyed deadend towers.

In addition Tower 10-lAC was inserted between 10-lC and 10-2C thus dividing a 4747 1 span into a 3769 1 and a 978 1 span to avoid deadending and improve side swing conductor clearance.

Refer to as-built structure sheets and plan and profile drawings for the final design of these long spans. Also see ~xhibit 8-3 for a summary of long span design. As-built stations and spans differ slightly from Exhibit 8-3.

C. Self-Supporting Deadend Towers

For six sites with steep topography two self-supporting deadend tower designs were utilized: a four-leg w-frame structure (STw-SSA) with 35' phase spacing and a design (ST3-SSA) using separate A-frame structures for phase spacing greater than 35 1 Refer to Exhibit 8-4 for tower outlines.

Rockbolt foundations were used with a grout pad for each leg. Insulator assemblies for the self-supporting towers are similar to other deadend towers. Refer to IEGO Drawing 2708-TS-122, 133, 150 and 151 as well as ITT-Meyer drawings 2572, Sheets 106 to 121 for various self-supporting tower details.

ST3-SSA self-supporting towers were used at 02-1C and 03-1C. STw-SSA self-supporting towers were used at 04-1C, 30-1W, 34-2W and 35-2W. Use of a STw-SSA tower at 10-2C was avoided by inserting Tower 10-lAC.

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2.2 PHASE SPACING REQUIREMENTS

A. Original Design

The original design called for 35 1 phase spacing on the 13 long spans.

8. Design Changes

The final design provides increased mid-span phase spacing, per Exhibit 8-3 attachment, ranging from 35 1 to 65 1

This revision increased clearing requirements along the right-of-way and expanded tower sites to accommodate increased pole spacing. G~ing became more difficult and in two cases ST3-SSA self-supporting deadend towers had to be used where deadend g~ing was made impossible due to the need for increased phase spacing.

2.3 CONDUCTOR SIDE SWING CLEARANCE

A study of side-swing conductor clearances on long spans was undertaken following the increased phase spacing. A summary of findings and design revisions is given in Exhibit 8-5.

Tower heights of 7-2C and 36-W were increased and towers 8-2C and lO-lC were inserted to ensure adequate side swing clearance.

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SECTION 3 BLIND SLOUGH REALIGNMENT

The Blind Slough section of the Tyee Lake transmission line is located between wood poles 64-1M and 66-lM on Mitkof Island. The transmission line right-of-way in this section pas'ses through an environmentally sensitive part of the Tongass National Forest.

3.1 ORIGINAL DESIGN

The original design alignment was routed on the uphill side (North and East) of Mitkof Highway, away from the Blind Slough sensitive area. Steel X-frame towers were specified (STX-E10).

3.2 DESIGN REVISIONS

The U.S. Forest Service refused to grant right-of-way for this alignment because of concern over severe and unmanageable soil stability problems' on the steep hillside portions of this route and fears that right-of-way clearing would remove the only measure of soil stabi 1 ity.

IECO implemented a decision by the U.S.F.S. Supervisor to reroute the line along Mitkof Highway on the downhill side (South and West) using wood pole construction. Refer to Appendix C, Exhibit C-1 for the forest supervisor's decision of March 15, 1982.

The Blind Slough Realignment resulted in the replacement of 9 steel towers - which had been fabricated and were delivered - by 19 wood poles of predominantly HPT-1B pole top construction. Refer to as-built structure sheets and plan and profile drawings for final alignment detail s.

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SECTION 4 FOUNDATION AND ANCHOR DESIGt~

Foundations and anchors underwent considerable revision to adapt to extensive poor bearing capacity soil (e.g. muskeg) and special construction circumstances. Foundations and anchors shown in the Basic Design Manual should be disregarded; complete final designs are shown in the record construction drawings submitted separately. Selected final designs are shown hereafter in Appendices D and E.

4. 1 ORIGINAL DESIGN

The original design included the following:

Foundations

Unit Description Drawing

TSF-l(* ) Rockbo1t (2) HP 8 x 36 2708-TS-97 TSF-1A(*) Rockbo1t (2) HP 14 x 89 2708-TS-98 TSF-2 Single Rockbo1t 2708-TS-99 TSF-6 Driven Pile 2708-TS-1 01 TSF-8 Screw Tripod 2708-TS-102 TSF-9 Battered Driven Piles 2708-TS-100

Anchors

Unit Descripti on Drawing

TA-1-(*) Log Anchors 2708-TS-49, 78 TA-2A, B or C Roc k Anc ho rs 2708-TS-50, 81 TA-3A, or B Plate Anchors 2708-TS-79, 95 TA-4S Screw Anchors 2708-TS-96

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Miscellaneous units were also included for anchor rod extensions, pile-top cut and weld, excavation and backfill.

4.2 FINAL DESIGNS

Several new designs and design modifications were developed to suit extensive muskeg and other poor soil conditions as well as special field situations. These design changes are described briefly below:

A. Foundations (see Appendix D for Foundation Designs below)

1. TSF-6A - Battered pile with straight pile, Drawing 2708-TS-llS. This battered pile design was issued for use in area of shallow muskeg, principally on Mitkof Island. The battered pile adds lateral support to the straight pile footing.

2. TSF-7 and 7A - Embedded pile foundations, Drawings 2708-TS-112 and 128. These foundations were designed for non-submerged and non-solid rock soil conditions for which pile driving would be difficult. In addition, grillage platforms consisting of HP segments welded to the pile footing were designed in the cases of two towers to increase bearing surface in poor soil situations.

3. TSF-8B - Screw Anchor Tripod Footing, Drawing 2708-TS-131. This foundation design was issued for use in areas of muskeg or other poor soil overlying firm bearing soil.

4. Miscellaneous Designs such as a 4-pile cluster at l7-3C were used. Please refer to record drawing 2708-TS-16S.

B. Anchors (see Appendix E for Anchor Designs below)

1. TA-3BR - Heavy Log Anchor, Drawing 2708-TS-138. The heavy log anchor was designed using a typical 121 Alaskan yellow cedar log to replace plate anchors (TA-3B) and barrel anchors (TA-4S-SS).

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2. TA-4S-55 - Concrete Barrel Anchor, Drawing 270B-TS-114. The barrel anchor was designed for use in muskeg soil before the anchor testing program. This anchor failed to develop sufficient capacity where installed in muskeg, as revealed by late testing. The heavy plate anchor suffered similar failures.

The TA-4S-55 and TA-3B anchors which failed under test or were suspected of insufficient capacity were either replaced by heavy log anchors (TA-3BR) or stabilized by driving two log stakes ahead of the anchors and on each side of the anchor rod.

3. Miscellaneous Anchor Variations were implemented, such as a heavy triple plate anchor composed of 3 heavy plate anchors welded end to end. Please refer to record drawings.

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SECTION 5 INSULATOR HARDWARE ASSEMBLIES

Insulator hardware assemblies, as described in the Basic Design Manual and record drawings 2708-TS-51 through 69, were used extensively without changes. New designs for insulator reversal, a polymer insulator V-string, a tangent-strain assembly and speCial conductor stand-off units on ST3-E55 towers and jumper assemblies were among the major design changes.

5.1 ORIGINAL DESIGN

Refer to record drawings cited above for original designs. The basic insulator hardware assemblies consisted of suspension I-strings with and without keeper strut insulators, a V-string, double and single string strain assemblies, and double and single string suspension running angle assemblies. Insulators are porcelain bell insulators of 15,000 - 40,000 lb. M&E rating.

5.2 NEW DESIGNS AND DESIGN CHANGES

a. Reversed Insulator Assemblies were designed for several standard assemblies for use where conductor departure angles for everyday conditions are above the horizontal. Refer to IECO Drawing 2708-TS-118 for a typical reversed insulator assembly. Reversed insulator assemblies were installed at the two steepest tower sites only.

b. Polymer Insulator V-String at 01-lC was designed to counter a potential bowing problem in the standard V-string due to insufficient vertical load, even with hold down weights attached. Refere to IECO Drawing 2708-TS-136.

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c. Tangent-Strain Assembly TMI-20M was modified to adapt to the tangent tower crossarm vangs. Refer to IECO Drawing 2708-TS-120.

d. The ST3-E55 Jumper Assembly was modified by the addition of an extra strut "insulator and/or the emplacement of special conductor stand-off units at the lower yoke of the double string strain assemblies. Refer to IECO Drawing 2708-TS-160 for details. This design modification was required to correct insufficient jumper conductor to guy wire clearances discovered after stringing. A complete analysis of vibration effects on the conductor stand-off units was performed.

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SECTION 6 TOWER DESIGN

Tower deSign modifications and new designs included self-supporting deadend towers, a revision of the guying arrangement for ST3-E55 towers, manufacturer - imposed guying limitation changes, tower vibration protection, and STX-E10 guy YOke re-design.

A. Self-Supporting Deadend Towers

Refer to discussion under Section 2.1.

ST w-SSA (4-leg, 35' phase spacing) towers and ST3-SSA (three independent A-frame) towers were designed to replace deadend towers at sites which precluded guyed deadend towers.

B. ST3-E55 Tower Design

As originally designed, the ST3-E55 tower had a guying arrangement similar to that of the ST3-E54 (deleted). Refer to IECO Drawing 270B-TS-10. The-requirement of deadend capability for this design greatly increased pole size as well as guying loads and anchor capacity requirements for the outside pole.

The ST3-E55 was re-designed to consist of three independently guyed poles with a guy spread angle of 30 each side of the conductor line. Refer to ITT-Meyer Drawing 2572, Sheet 101 for a typical ST3-E55 tower configuration. This resulted in a much less expensive tower.

C. Guying Requirements

Original guying design specifications called for stressing guys to no more than 90% of UTS, as allowed by NESC Rule 26l.C.l.

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Specifications also called for a tower system design which would ensure the following failure sequence: guy yoke,_ crossann, complete guy system, and last, tower body. The tower manufacturer could not ensure this failure sequence using the 9~ UTS as specified, and dictated a 65% UTS limit for guy stress. This change substantially increased the number of guys and anchors used on several towers. For instance, the ST3-E53 tower arrangement was revised from 24 guys and 20 anchors to 31 guys and 27 anchors. Refer to drawings 2708-TS-83 and 84 for guy arrangements.

D. Tower Vibration Protection

Control of wind-induced tower vibration was a major concern, especially in light of vibration - caused failures of similar structures on the Copper Valley transmission line. The addition of vibration spoilers was chosen over additional guying as the preferred vibration control method. Vibration spoilers consist of 5' sections of 2" x 2" angle fitted along the length of structure legs or poles in a staggered arrangement. Refer to ITT -r~eyer Drawi ngs 2572, Sheets 93, 95 and 104 for spoiler details and a list of those towers fitted with spoilers.

Vibration spoilers were designed to be attached via stud bolts welded to tower members or via bolts attached to bands fitted around tower members.

The criteria used for detennining which towers would be fitted with vibration spoilers were:

1. All ST3-E53 and ST3-E55 towers, thought most susceptible to vibration damage due to the pin-pin end fixity design;

2. Towers whose legs or columns had an LID ratio greater than 30, where L is unsupported length and D is average outside di ameter;

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3. Towers exposed to continuous laminar wind flow in more open areas.

E. Guy Yoke of STX-E10 Towers

The original guy yoke design for the STX-E10 towers did not yield under test at a load sufficiently low to ensure the required failure sequence. A guy yoke extender was designed to be inserted between the original guy yoke and the tail guy. The ~uy yoke extender is designed around a shear bolt tested to shear at 13. The extender was required because all STX-E10 yokes per the original design had been installed on erected towers . Refer to ITT-Meyer Drawing 2572, Sheet 12 for details.

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SECTION 7 LONGITUDINAL LOAD CAPABILITY

Suspension towers and their guy systems are designed for the following longitudinal load capabilities:

Tower

STX-El 0 STX-E30 STw -E50

* per phase

Longitudinal Load*

The suspension tower guy system design includes a guy yoke to which attach two down guys from the tower crossarm and the tail guys to the anchors. ahead and back of each tower (refer to IECO Drawing 270B-T5-1. for instance). The guy yoke performs two functions:

1. Longitudinal Load and Guy Stress Relief - If the guy system is overstressed due to unbalanced ice loads or broken conductors. the guy yoke will buckle - or on the STX-E10 tower a shear pin will shear - allowing the tower to tilt and the guy system to extend thus reducing stress (see Exhibit 8-2).

2. Guy Tension Equalization - Should one guy be stressed more than the other due to unbalanced loads on one phase only or foundation settlement the guy yoke freedom to rotate will tend to equalize guy tension.

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The tower system with guy yokes provides Significant protection against cascading failures due to longitudinal load imbalances. In a study made to determine the effect of unbalanced ice loading on STX-E10 towers it was found that longitudinal loads due to extreme cases of ice imbalance did not exceed 1.2k or 40t of the per phase design load (3k) for the tower system.

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SECTION 8 SHOEMAKER BAY-WRANGELL TIE LINE

The Shoemaker Bay-Wrangell 138 kY tie line is a 17,460 feet (3.30 mile) wood pole line and interconnects the North Wrangell Switchyard with the Wrangell Substation, located inside the City of Wrangell. Initial operation of the tie line will be at 69 kY.

12,270 feet (2.32 miles) of the Shoemaker Bay-Wrangell tie line is located in State of Alaska lands with the remaining 5,190 feet (.98 mile) running along the Zimovia Highway and requiring the incorporation of an existing 7.2/12.5 kY distribution line as underbuild construction.

Design criteria for the tie line are contained in Exhibit F-1 of Appendix F, Basic Design Manual.

Right-of-way width for land acquisition purposes was 80 feet from the Wrangell Switchyard up to the Zimovia Highway and 40 feet along the highway, where shorter spans were dictated by the distribution underbuild as well as the highway alignment. The determination of right-of-way requirements is detailed in Exhibit F-2 of Appendix F, Right-of-Way Requirements.

As the transmission line runs adjacent to two rock quarries located 'inside State of Alaska lands, alignment details were submitted to the Alaska Department of Natural Resources for its review and approval. Also submitted to ADNR was a detailed evaluation of the impact of the transmission line on operations at the North Rainbow Quarry along with recommendA b1asting guidelines.

t~

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The entire alignment of the Shoemaker Bay-Wrangell tie line along the Zimovia Highway was reviewed in the field with representatives of the Alaska Department of Transportation and all ADOT requirements were incorporated into the final design of the line.

Basic material substitutions that occurred during the construction of the Shoemaker Bay-Wrangell tie line are as follows:

1. The substitution of Dove Conductor with UNOVA greased core for Dove/AW conductor for the 138 kV transmission.

2. The substitution of Ohio Brass MHi-Lite" polymer line post insulators for standard porcelain post insulators for the 138 kV transmission.

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SECTION 9 SUBr~ARINE CABLES AND SUBMARINE CABLE TERMINALS

The transmission system includes approximately 11.4 miles of submarine cable located in four crossings: Bradfield Canal, Zimovia Strait, Stikine Strait and Sumner Strait. The submarine cable is oil-filled with 500 kcmi1, 46 hollow strand copper conductor (see attached Furukawa Drawing SOFL-8122). Each crossing consists of four cables, one for each phase and one spare cable. Cable separation is approximately equal to water depth.

The transition to overhead transmission occurs via submarine cable terminals located at each end of each crossing. The submarine cable is terminated in a special pothead with parallel surge arrester. The submarine cable is linked from the pothead to the overhead conductors via a transfer bus with manual disconnect switches used to switch out a faulted cable and switch in the spare cable.

Each tenni na1 has outer gas type oi 1 pressure tanks, an oi 1 feedi ng system, cable terminations, an overhead transmission line terminal structure, and the transfer bus. In addition one terminal of each crossing is the location for a back-up bellows type oil pressure tank and the oil alarm system apparatus. The oil alarm system detects low oil pressure and transmits this information to the Wrangell Control Center via radio frequency signal. The RF signal is sent from North Cleveland to Wrangell Control via a repeater located on Etolin Island, while signal transmissions to/from the other three terminals are line of sight. For complete design details refer to the Furukawa record drawings and O&M Manual.

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-.-

Thickness, mils(mm) Diameter, mils(riir.l) CD Oil duct Min. 3.8(0.97) Min. 500(12.7)~.D Conductor 1017 (25.84) 0) Strand Shielding 10.2(0.26)}Min.Avg 1038 (26.36) 0 Insulation 505(12.83) 505(12.83) 2048 (52.02) Insulation Shielding 15.7(0.40) 2080 (52.82) Lead Sheath Min.Avg. 110(2.8) 2300 (58.42) e Bedding for Reinforcement 18.1(0.46 ) 2336 (59.34) Reinforcement 11.8(0.30) 2360 (59.94) Binder ~or Reinforcement 18.1(0.46) 2396 (60.86) @ Anti-Corrosion jacket 157 (4.0) 2711 (68.86) @ Bedding for Armour 39 .4( 1.0) 2790 (70.86) @ Armour 238 (6.05) 3266 (82.96) @ . Serving 138 (3.5) 3542 (90.0)

THE 3RO ANGLE FOR .........

PROJECTION SCAlE( D~EN~ON 18th - Nov:- 1981 NOMENCLATURE Mils mm 1 1

APPO BY,I(. g;~~.L ...........................

WT 138 kV Single Core 500 f1CM 22.7 kg/m CHECKE~ . ..IL. ". / SNO DESIGNE~/~ / Oil-filled Submarine Cable ONO TRACERY ... Ir:;e,. Ic:... / SOFL-S122 THE FURUKAWA ELECTRIC CO LTD. REVISIONS

I

SECTION 10 COMPARATIVE LISTING OF CHANGES IN DESIGN ITEMS

The main purpose of this part is to present a quick reference and a guide in the design changes made to the transmission line and submarine cables and terminals in the course of the project.

A. Overhead Transmission Lines

Item No. ________ ~P~e~r~B~i~d~ ______ __

1.0 STEEL TOWERS

1.1 All deadend towers were of the guyed, 3-po1e type (STE-E55, -E53) .

1.2 No special vibration control method was specified except LID ratios were given.

1.3 STX-E10 guy yoke used square tube.

1.4 Guys to be stressed no more than 90% UTS under maximum loads.

2.0 FOUNDATIONS

2.1 Rockbolt footings designed considering minimum rock excavation.

10 - 1

Item No. ________ ~A~s~-B~u~i~l~t ________ _

1.1 Self-supporting A-frame and 'If -frame towers (6 total) were used where standard guying was impossible due to steep terrai n.

1.2 Vibration spoilers (steel angles) were added to poles of ST3-E55 and ST3-E53 to\'lers as well as X-frame and 'If-frame structures more exposed to laminar wind and with excessive LID ratios.

1.3 STX-E10 guy yoke was modified with extension plates and shear pins to attain desired buckling under design exces-sive longitudinal loads (N13 k).

1.4 Guys are stressed no more than 65% of UTS under maxi-mum loads.

2.1 Limited exposure of rockbolts and rock chipping allowed to facilitate easier construc-tion.

B809/2145p0067:0175p

Item Item No. Per Bid No. As-Bui 1 t

2.2 No embedded pile footings 2.2 TSF-7 and TSF-7a embedded pile in bi d. footings added for use in non-

submerged and non-solid rock-soil conditions upon disclo-sure of such soils.

2.3 No battered pile support for 2.3 Special driven footing alter-driven pile footing in bid. nate TSF-6A. 6B with battered

pile added for use with STX-E10 towers in shallow mus-keg.

2.4 No provision for tripod foot- 2.4 Tripod footing TSF-8B with ing installation through deep pipe extensions introduced for muskeg overburden. use in situations of deep mus-

keg disclosure.

2.5 No designs included for grill- 2.5 Steel pile grillages installed age footings for extra on towers 30-2W and 41-W. compression strength in bear-ing type soils.

3.0 ANCHORS

3.1 No barrel anchor for use in 3.1 Barrel anchor filled with con-muskeg situations. crete (TA-4S-55) used in

muskeg areas. Some were modi-field by driving two wood posts ahead of anchor for additional strength.

3.2 Log anchors limited to TA-1-5 3.2 Heavy log anchor TA-3BR intro-and TA-1-8. duced using rot-resistant

Alaska yellow cedar and up to 18 feet long.

4.0 INSULATORS AND HARDWARE

4.1 No self-supporting tower 4.1 TMI-21 and TMI-23 insulator insulator assemblies in bid. assemblies added for use on due no self-supporting self-supporting towers. towers in bid. !4.2 Tower Ol-lC used standard 4.2 TMI-22 insulator assembly V-string with porcelain V-string with polymer insula-

.. '. insulators and tie down tors used with tie down weights. weights to prevent excessive

bowing of V-string. ~ ,p

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Item Item No. Per Bid No. As-Buil t

4.3 TMI-14 with strut insulator 4.3 Strut insulator deleted to used on ST3-E51 towers. eliminate undesirable bending

in hardware connections.

4.4 TMI-20 designed for use with 4.4 TMI-20M modified for crossarm STX-E36 towers, crossarm vang hole orientation, perpen-,o&~,

vang hole oriented 10ngitu- dicu1ar to TIL centerline, per dina11y (with TIL centerline). tower fahricator design.

4.5 No reversed insulator assem- 4.5 TMI-02R, reversed insulator ~,\ b1ies. assemblies for standard TMI-02

used at 40-5W and 41-1W upon disclosure of steeper slopes ~' between towers.

4.6 TMI-18 and TMI-19 standard 4.6 Addition of extra strut insu-strain assemblies used on 1ator and installation of ST3-E55 towers. locally fabricated conductor

stand-off units, used for increasing jumper conductor to guy wire clearance. On tower 00-lC an aluminum bus was used with extra strut insulator.

4.7 Tie-down weights ranged from 4.7 Tie down weights up to TM-99 (1) to TM-99 (3.5), 650 pounds, TM-99 (6.5), used. 100 to 350 pounds.

4.8 Strut insulator used on 4.8 Strut insulator deleted from STX-E37 towers. center phase of all STX-E37

towers, due tower fabricator misplacement of strut vang.

5.0 TOWER SPOTTING AND WOOD POLE LINE MITKOF ISLAND

5.1 Blind slough area designed 5.1 Blind slough area constructed with STX-E10 structures on using wood poles, HPT-1B pole hillside, east of Mitkof top, west of Mitkof Highway. Hi ghway.

5.2 Phase spacing at long spans 5.2 Phase spacing up to 65 feet limited to 35 feet. used for long spans per

BOC/APA directive.

.. c~,~ 5.3 No towers 8-2C and 10-lAC. 5.3 STX-E36 towers 8-2C and 10-lAC inserted for side swing

;,.--M clearance reasons and in one case to avoid the use of a self-supporting tower.

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Item No Per B,"d

. ----------~~-----------5.4 24.9 kV underbuild included

in vicinity of Petersburg substati on.

5.5 Long spans (over 4000 1 ) de-si gned with strong 1f -frame suspension structures and some guyed deadends.

6.0 SHOEMAKER BAY-WRANGELL TIE LINE

6.1 No tie line in original work scope.

6.2 No guy insulators included in ori gi na 1 desi gn.

6.3 No guy and guy anchor at pole stub and overhead guy.

6.4 Pole 2-11 designed with pole stub and overhead guy.

6.5 Pole 3-8 was designed as deadend structure for slack span entrance into Wrangell Substation.

B. Sublllar"ine Cabl e and Terminal s

Item No. ________ ~P~e~r~B~i~d~ ______ __

1.0 Bradfield Crossing planned route.

2.0 Roofed enclosure for oil equipment.

Item No. ________ ~A=s~-B~u~i~l~t ________ _

5.4 24.9 kV underbuild in vicinity of Petersburg substation deleted.

5.5 All long spans constructed with deadend capability per BOC/APA direction.

6.1 Tie line added.

6.2 "Johnny ball II insulators and fiberglass insulator guy rods incorporated in a few in-stances for increased safety.

6.3 Guy and anchor added at pole 2-5 as poor soil conditions precluded the installation of a pole key.

6.4 Pole stub and overhead guy deleted at pole 2-11 and con-crete backfill installed for transverse support.

6.5 Deadending of 138 kV transmis-sion was changed to pole 3-7 as deadend guying at pole 3-8 would have interfered with substation roadway.

Item No. ________ ~A=s~-B~u~i~l~t ________ _

1.0 Bradfield Crossing planned route revised to minimize hazards.

1.0 Roof deleted for cost savings.

10 - 4 B809/2145p0067:0175p

Item Item No. Per Bid No. As-Built

3.0 Grips and anchors used for 3.0 All anchors and grips deleted submarine cable anchorage at except at Bradfield Canal shore ends. shore ends for cost savings.

4.0 Pothead supports were straight 4.0 Butt plates added for greater pile columns, no bearing plate. bearing support.

5.0 No protective cover for solar 5.0 Transparent polycarbonate panels other than glass. cover added for extra protec-

tion. "'W

10 - 5 BB09/2145p0067:017Sp

APPENDIX A BASIC DESIGN w\NUAL REVISIONS

-APPENDIX A BASIC DESIGN MANUAL REVISIONS

The following list of annotations should be used as reference when using the Basic Design Manual. The annotations are presented by chapter with a page reference where appropriate.

Chapter 2

p. 2-1

p. 2-3

Summary Data

Line lengths and other data are no longer correct. Refer to Table A at the end of this Appendix for overhead line data.

Drawing 2-1 does not reflect the final design using 37 No.8 AW all the way to the powerhouse, the Blind Slough alignment changes, or the addition of the Shoemaker Bay-Wrangell tie line (refer to record drawings).

p. 2-4, 2-5 Same comment as p. 2-1.

p. 2-7 Final design also includes 3-co1umn guyed structures and self-supporting deadend towers. Refer to record drawings.

Note: The statement that w-frame towers are used for 37 No. 8 AW sections and X-towers for Dove sections is not exclusive. STX-E30 towers were used extensively in 37 No. 8 AW sections as well as the STw towers.

Chapter 3 Basic REA and NESC Requirements

NESC Rule 26l.C.1 states guys shall not be stressed beyond 90% UTS. A 65% UTS limit was adopted for the present project to ensure design failure sequence.

A - 1 8809/2l45p0052:0150p

Chapter 4

p. 4.2

p. 4.3

....

p. 4-7

-

p. 4-19

p. 4-21

p. 4-22

p. 4-23

.-

....

Line Design Technical Analysis

Length of sections is revis~d. Refer to Table A.

The unit weight of Dove ACSR/AW is 0.7291 lbs/ft. The unit weight 0.766 lbs/ft applies to the Dove ACSR used on the Shoemaker Bay-Wrangell tie line .

Section 4.2 on Insulators does not discuss the numerous changes made to insulator assemblies. Refer to Section 5 of this report and record drawings.

Section 4.S on Footings has changed substantially. TSF-3, TSF-4 and TSF-S (as shown in Exhibit A-10) are deleted. TSF-6 uses HP 8 x 36 instead of HP 10 x 42. TSF-2 and TSF-7 are revised. Refer to Section 4 of this report and record drawings.

Section 4.6 on Anchors should be expanded to include barrel and log anchors. Refer to Section 4 of this report and record drawings.

19 No.7 AW guy wire was used in place of 7 No.9.

Drawing 4-8 is no longer applicable due to guying changes mentioned in Section 6, Part C of this report. Refer to record drawing 2708-TS-83 and 84 for guying arrangement details .

A - 2 B809/2145p0052:0150p

-.....

TABLE A

TYEE LAKE HYDROELECTRIC PROJECT

Overhead Transm1ss1on L1ne Data

TOTAL CON DUe TOR S TOWERS I POLES VOLTAGE1 SEGMENT , bENGTH BETWEEN LENGTH TYPE MILES TOWERSjPOLES TYPE OTY LEVEL ~ 13.4 0-1 end 13-1 STX-El 14 AW STX-E3 10

CLEVELAND 17.3 Total 13.4 STJ-5 12 138 kV PENINSULA MILES ~ ST3-EI 2 CSR/AW 3.9 3-1 end 17-3 SSA 3 STw-5 4

Total II SUBTOTAl 45 ~ No 8 7.1 3-5 end 30-2 STX-EI 46

IIMNGELL ~ 4.8 ~-1 end 38-1 STX-E3 8 ISLAHD 23.5 Total

.!h! STJ-EI 6 -extl. MILES STJ-E5 12 138 kV SHOEMAKER Dove

BAY-WRANGELL I~ 4.5 9-1 Ind 23-5 STw-E5 3 TIE LINE 3.1 0-2 end 34-1 SSA 3 4.0 8-1 Ind 42-5

Total 11.6 SUBTOTAl 78 Dove

3.3 ACSR 3.3 0-1 end 3-8 138 kV MILES Woodpoles

SHOEMAKER (TRANS Class BAY-IIMNGELL Total hl HI I H2 48 TIE LINE 1.1 12.5(7.2 kV

MILES Raven lit 1.1 2-5 end 3-7 Distribution (DISTR) Underbuilt Total 1.1 See Note 2

SUBTOTAl 48

Dove 3.2 ACSR/AW 3.2 45-1 end 49-1 STX-EI 12 WORONKOFSV.I MILES ST3-El 4 138 kV

ISLAND Total g SUBTOTAL 16

Dove VANK 2.8 ACSR/AW 2.8 52-lind 55-2 STX-EI 10 ISLAHD MILES Total U ST3-EI 3 138 ltV

SUBTOTAL 13

21.3 ~~R{AW ~ MILES (TRANS 11.1 59-1 and 70-4 2.4 73-Hi and 76-2 STX-El 43

STJ-EI 8 Total 13.5 138 ltV

SUBTOTAL 51 HITKOF Dahlia Poles

""Af\ 3.6 70-4 and 73-lE --ISLAND 4.2 76-2 and 80-28 Class HI 168 Class 2 62 24.9/14.4 ltV

Total 1..& Distribution 7.8 Underbull t MILES Penguin See Note 2 (DISTR) lli. 3.6 70-4 and 73-!~ 4.2 76-2 end BO-28

Total L! SUBTOTAL 230

1. Transm1ss10!l voltage level 1s design. Operat1ng voltage will be 69 ~" ~or In 1ndefinite period .

2. The C1t1es of Wrlngell end Petersburg Ire respons1ble for the operat1on and ma1ntenance of the distribution underbuild on APA transmission poles.

APPENDIX B

LONG SPANS

(No Exhibit B-1 included)

C_" .. -,

FIGURE 1.

Guy

-~-

FAILURE cm ... ,INMENT DUE TO BROKEN CONDUCTOR

v Yoke Box

__ Insulator String

SUSPENSION TOWERS WITH INTACT CONDUCTOR

EXH. r B-2

Conductor

Break

CONDUCTOR BREAKS, UNBAL. TENSION < 70% AVE. DAILY @ TOWERS A & B, GUYS SUPPORTING

Break

--7" Yokes Yleld--_'II~ Elongate

B CONDUCTOR BREAKS, UNBAL. TENSION> 70% AVE. DAILY @ TOWERS A & S, YOKES YIELD BUT GUYS HOLD

IT! >< :J: ......

co ......

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N

I ;, It,

TYEE LAKE 138 KV

SUMMARY OF LONG

SPAN ORIGINAL fINAL REQ'O MIO-LENGTH SUPPORTING TOWER TOWER SPAN PHASE ( feet) TOWER STATION TYPE TYPE SPACING

02-lC 799+14.74 ml'-E50 ST3-SSA

1) 6,024 60 ft. 03-IC 738+91. 00 STlr-E50 STJ-SSA

03-lC (See description above) 2) 5,077 35 ft.

04-lC 688+13.94 ST3-E52 mr-SSA

05-2C 624+64.00 Snr-E50 No Change

3) 6,434 50 ft. 06-1C 560+30.20 STJ-E53 No Change

,

HYDROElECTRIC TRANSMISSION

SPAN DEADENO

FINAL MIO-SPAN PHASE

SPACING

60 ft.

60 ft.

50 ft.

I: j. I iBI. ",j;' 1 .

PROJECT TM - 9/23/82 LINE

Sheet _1_of_5_ TOWER DESIGN

REMARKS

Guying of ST3-E55 is not possibl~. A ST3-SSA self-supporting D.E. tower with 35 ft. phase spacfng will be used. Due to terrain limitations, a STn-SSA cannot be placed. Tower center has been relocated 10 ft. SE to better ground.

Guying of ST3-E55 is not possible, A ST3-SSA self-supporting D.E. tower w1th 85 ft. phase spacing will be used. Tower center has been relocated 70.5 ft. SE to better ground.

(See description above)

~uying of ST3-E53 1s not possible. A ST~-SSA self-supporting D.E. tower with 35 ft. phase spacing w1ll be used. Tower center has been relocated 12.9 ft. NW to better ground.

Guying of ST3-E55 is not possible, Deedend will be pIeced at Tower 05-lC, 851 ft. upstation, and Tower 05-2C will remain a ST.-E50 with 35 ft. phase spacing; to a STJ-E55.

Tower 05-lC has been changed

Originally designed as a ST3-E53, Tower 06-1C has been re-staked at 65 ft. phase spacing to achieve midspan phase separation of 50 ft.

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W

, if :t ~ t

TYEE LAKE 138 I:V

SU~"4ARY OF LONG

SPAN ORIGINAL FINAL REQ'D HID-LENGTH SUPPOr.T I IlG TmlER To.IER SPAN PHASE lliill To.IE R STATION TYPE TYPE SPACING

07-2t 512+00.00 ST1I'-E50 ST3-E55

4) 5,215 35 ft. 08-1t 459+85.08 ST1t-E50 ST3-E55

08-1t (See description above) 5) 4,635 35 ft.

09-1t 413+50.00 STlI'-E50 STJ-E55

10-1C 380+32.00 5T3-E53 STJ-E51

6) 4.747 20 ft. 10-2C 332+85.00 ST'II'-E50 STx-E30

~.

IIYOROELECTRIC TRANSllI $S I O~ SPAN OEI.OEllO

FINAL MID-SPAN PHASE

SPf.CING

35 ft.

35 ft.

~> 4 I < :I: ......

OJ ......

---f OJ I

W

:.. ......

SPAN LENGTH ~

7) 4,658

8) 4.625

9) 4,097

"' i

SUPPORTING TOWER

12-2C

13-1C

25-4W

26-1W

27-2W

28-1W

STATION

252+72.00

"

ORIGINAl TOWER TYPE

ST1I"-E50

206+14.20 ST3-E55

901+39.71 STtT-E50

855+15.00 STfT-E50

815+86.00 STX-E30

774+88.68 ST3-E52

",- I

TYEE LAKE HYDROELtCTRIC PROJECT 138 KY TRANSMISSION LINE

I i ;;, "

TM - 9/. ,2

SUMMARY OF LONG SPAN DEADEND TOWER DESIGN Sheet_3 _of ~

FINAL TOWER TYPE

5T3-E55

No change

No change

ST3-E55

STfr-E50

ST3-E53

REQ'D MID-SPAN PHASE

SPACING

35 ft.

35 ft.

35 ft.

FINAL HID-SPAN PHASE

SPACING

35 ft.

35 ft.

35 ft.

REMARKS

Guying of ST3-E55 is possible. Tower 12-2C has been changed to a ST3-E55 with 35 ft. phase spacing.

Originally designed as a ST3-E55. "Tower 13-IC has been re-staked at 35 ft. phase spacing.

Guying of 5T3-E55 is not possible. Deadend will be placed at Tower 25-3W. 787 ft. upstation, and Tower 25-4W will remain a STr-E50 with 35 ft. phase spacing. Tower 25-3W has been changed to a ST3-E55.

Guying of ST3-E55 is possible. Tower 26-1W has been changed to a ST3-E55 with 35 ft. phase spacing.

Guying of ST3-E55 is not possible. Deadend will be placed at Tower 27-IW, 674 ft. upstation. and Tower 27-2W will be changed to a 5TW-E50 with 35 ft. phase spacing. Tower 27-1W has been changed to a ST3-E55.

Guying of ST3-E53 is possible. Tower 28-1W has been changed to a ST3-E53 with 35 ft. phase spacing.

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co ......

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SPAN LENGTH ~

10) 4.773

11) 5,120

SUPPORTING TOWER

30-1W

30-2W

34-1W

34-2W

STATION

685+32.99

637+60.00

476+22.0()

425+02.12

ORIGINAL TOWER ~

S13-E51

ST3-E55

S13-E53

S13-E52

-,.

TYEE LAKE HYDROELECTRIC PROJECT 138 KV TRANSMISSION LINE

TM - 9/23/82

SUMMARY OF LONG SPAN OEAOENO TOWER DESIGN Sheet_4 _of_5_

FINAL TOWER TYPE

snr-SSA

NO change

NO change

sa-SSA

REQ'O MID-SPAN PHASE

SPACING

35 ft.

35 ft.

FINAL MID-SPAN PHASE

SPACING

35 ft.

35 ft.

REM ARK S

Guying of a ST3-E55 1s not possible. A STn-SSA self-support1ng O.E. tower with 35 ft. phase spacing w1ll be used.

Originally designed as a ST3-E55. Tower 30-2W has been re-staked at 35 ft. phase spacing.

Orig1nally designed as a ST3-E53 with 35 ft. phase spacing.

Guying of ST3-E53 is not possible. A ST-SSA self-supporting O.E. tower with 35 ft. phase spacing w1ll be used.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - -- - - .'. -- - - - - - - - - - - - - --- - - - - -

35-2W 390+02.17 ST3-E51

12) 5,482 36-1W 335+20.00 STI'-E50

STll- SSA

35 ft. S13-E55

35 ft.

Self-supporting deadend placed at 35-2W.

Guying of ST3-E55 is poss1ble. Tower 36-1W has been changed to a ST3-E55 w1th 35 ft. phase spacing.

rr1 >< :c .....

co .....

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W

SPAN LENGTH SUPPORTING ~ HJt/ER STATION

37-ZW 30Z+44.00

13) 8.087 38-1W ZZ1+57.10

ORIGINAL TOWER

TYPE

TYEE LAKE HYDROELECTRIC PROJECT 138 KV TRANSMISSION LINE

SUMMARY OF LONG SPAN DEADEND TOWER DESIGN

FINAL T(JtIER TYPE

REQ'D MID-SPAN PHASE

SPACING FINAL MID-SPAN PHASE

SPACING

TM - 9/Z3/8Z

Sheet_5 _of_5_

REMARKS

STft-E50 ST3-E55 Guying of ST3-E55 is possible. Tower 37-ZW his chlnged to I ST3-E55 with 65 ft. phase spacing.

65 ft. 5T3-E53 No change

65 ft. Originally designed IS a ST3-E53. Tower 38-1W his been re-staked at 65 ft. phase spacing.

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Vl ::r rt

U"1

@

@

...

SE.CTIQIJ A-A

L ..55"-0 I 35'-0 i I .. f':-,,-k~: JI

""

L qN(d1 T/.IlJ/AlAL VIE W

STTi-SSA TOWEl!

'...}!J.iJ' P:ltr r"'li!. OZ'/~J...~..()-FC.C """,:r PI."S WIAI/) OAi TOWElL HEAVY o/~KrIC;4J.. ~N() ..... A's. STJ'fINaINGI"'IfINrEN"'IVC~ C(Wf';A'rIOAl WITH .. ERTlCJIi_ LOAD ON >'NY I"I)(~I> -4'/") SII,fL..L.. BE

"'lfIAiTAII,/r;~ ;AI TNii' bE!> '''~.

$'. ALL l M/JS ~tJW" AI?E (/LTI .... A rc l OA~:S ~6 1.vc'IJII OrEIf{LlJAI> CAMclry I"ACr_ "" '.10.

(,. Wl'Ic.HT OF T1iW&,~ SH,4Lt.. 4F. C()A,sUd!I?G./) ,/oV1> ",.s;SlJlAEI:I Ta t!1i CA~.('IE /j .:QI/AL(.'( 81 EACH (.EG.

7. WWI> a./ TNII'f SillIl.L.. 8E t:ONSlc.t!l! ,..~ If ..... I/b CASE:: SHCW'" ,4/JJJ S""''-l.. ".RKE-SI"'(JN./J 7"') " w;u,IJ 1""'t:::;S-Ito: OF So I"$P "PI'(.;~O 1"-/ THG 7,f"~;SV.('S t>/REX. TiOV.

9: rc",~.t! Fovl,/bATIC>.vS SIMu.. CONSIs.7" 0'" ROCKIIQlJ RJCT;",c;,S AS SHC.WN. A,,'''c;1( eu..T'S SHALt.. eG EI1-l!I;;()I!!:l> IAI AlW- HT~i..'-Ic"L NvAi'SHlfila./RII.L.ED "''' .. ~ ~"'M'l'?:'< IS' IfiE".Or,MAr.i'l1 71) IE 404r ')"'. Pl."''" LIN.

Ie. F/llJJ:lCAr~R ,..,,"u.. S"PPLY ",,,,CI'fOR 80lTS c.t::H~'Erl: .....,TH #t.f7'.$

II. T~W"Je 1:. ,,;,," SH"L~ 1"'''Lvl:>(; C"MiJl"'G. P;'O"'.~ PK::JY151(,;NS RI2 'TJj ATTACNM!fAlT OF C';:A/~""C7c;;..f( ANi.- 7V,.,,';;E R "COP snpr;eAJ1i! ~ r,eJ;vc;.. AAl4 ~/GdI'~~ !'L.Ares" S"M'U'f~ To 7#,;;11" .s~./J ..,1oJ!}l-1C. C"~""'A-1r N.J. MOB -J!

11..11

1)

2)

SPAN LENGTH

5,215 ft.

4,635 ft.

3) 4,747 ft.

4) 5,482 ft.

,

"

SUPPORTING YO'",ER

07-2C

f

STATION

512+00.00

08-1t 459+B5.08

OB-1t 459+B5.08

09-1t 413+50.00

10-IC 3BO+32.oo

10-2C 332+85.00

35-2W 390+02.17

36-lW 335+20.00

TYEE LAKE HYDROELECTRIC PROJECT 138 KV TRANSMISSION LINE

SU~mRY OF CLEARANCE STUDIES

CLEARANCE SITUATION

Post-clearin9 survey indicated insufficient clearance 200 ft. downs tat ion from Tower 07-2C and 35 ft. from centerline.

Insufficient clearance found at station 434+08 approximately.

Post-clearing survey indicated insufficient sideswing clearance near Sta. 343+00.

Increased phase spacing (35 ft.) at Towers 35-2W and 36-lW created insufficient sideswing clearance.

f j i.

EXHI BIT B-5

PED - 9/28/82

RESOLUTION

Height of Tower 07-2C was increased from BO ft. to 90 ft.

Tower 8-2C added at station 434+08.

A new STX-E30 tower, Tower 10-IAC, was Inserted at Sta. 342+88.00 to limit sideswing of conductor.

Height of Tower 36-lW was increased from 50 ft. to 60 ft.

,~.

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co ......

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APPENDIX C U. S. FOREST SUPERVISOR'S DECISION MARCH 15, 1982

(BLIND SLOUGH REALIGNMENT)

.. '

...

....

~ (//-;;i\\ U"lted States .~a ...... -,,'j De ..... artment of

..... '"-"J" ... ",.,'::. - Agnculture

( Forest Service

TYEE PUUEr.LWE RIfuT_OF-tiAY LOCATION CL am RIVER \ SSFLATS AREA

HIlKOF ISLAND

FOREST SUPERV ISOR I S DEC IS lOt: 'IARCH 15. 1902

Forest Supervi sor John Hughes has se1 ected a conpror.li se route for the Tyee pO\ler transr.1ission line in the Blind River at"ea of ~Iitkof Island that r.linir.lizes the r.lajor ir.lpacts associated \lith each of the three alternative a1ignr.lents revie\led.

THE LINE HILL FOLLOH THE ORIGHlAL ROUTE ALOUG THE UPHILL SIDE OF THE HIGHHAY FRor.1 THE THREE LAKES LOOP ROAD lIESTItARD. CROSSING TO THE SOUTH SIDE OF THE HIGHUAY \lEST OF rVlN-r1ADE HOLE. THIS PORTION OF THE ALIG~;r~EUT ,\lILL TAKE ADVAIJT/\GE OF MJ EXISTItJG CLEARCUT EAST OF THE OVERSTEEPENED SLOPES, ~/HILE PRESEr.VWG THE UILDLlFE, UETLAlms, AIm RECREATION VALUES OF THE 'iAI;-flADE HOLE Ar.EA. A POLE LWE HILL BE SPECIFIED Fon THE REflAHlDER OF THE ROUTE ALOfJG THE DOW;HILL SIDE OF THE HIGHIJAY TO 1IHIHIlZE RIGHT-OF-\lAY CLEAnU;G UIHIL THE POHEnLWE CROSSES BACr. TO THE PREFERnED tjOrnH SIDE ALIGIlfIE IJT HEAR THE EAST EUD OF THE BLI NO SLOUGH CLEhRCUT. THE POLE LItlE ~/ILL BE COt!STRUCTED USIljG STATE-OF -THE-ART DES IGIJ TECHtJIQuES TO ELlIUW\TE THE POSSIOILITY OF RhPTOR ELECTROCUTIOrJ AtlO 11INHHZE POTEtJTIhL BIRD STRIKES. VEGETATION Ot~ THE Do\lt!HILL SIDE OF THE ROADIJAY \JILL BE RETAHlED \lHEREVER POSSIOLE AS A VISUAL AHD ACOUSTICAL BUFFER BETI/EEtJ THE HIGHI/AY AtJD BLIND RIVER Gf'!f,SSFLI.TS. STAtmWG TREES \tILL DE RErlOVED O~ILY \JHERE HEEDED FOR COIJSTRUCTIOtJ AIm PO'tIERLWE SAFETY.

The Forest Supervisor's decision is based on input fror.l 16 individuals, organizations, and agencies, and a re-exanination of alternative routes bj Forest Service staff officers and resource specialists.

During the 30-day revie\'l period leading "to this decision, public cor.lnents and recom.lendati ons \Jere received fror.l: Petersburg Ci ty Coullci 1, Petersburg Ut i 1 i ty Board, Thonas Bay PO'tler hlthori ty, Petersburg Char.lber of COI.1r.lerCe, \/range 11 Chanber of Cor.lnerce, Ui stri ct 2 Al a ska State Representati ve, ~l aska Departnent of Fish and Gar.le, U.S. Fish and Ui1d1ife Service, Petersburg Conservation Society, and seven individuals.

sur'lnARY OF AL TERIIATIVES CONS IDERED

ALTEP.NATIVE 1 (Uphill Side of High\lay P-ight-of-Hay)

Pub1 i c COl.lr.lent -- ,. r.lajori ty of those respond; ng ei ther preferred the original route adjacent to the high\1ay, or expressed \Iillingness to accept this a1ignr.1ent if their preferred route \'/as not selected. Several group and i ndi vi dual responses further suggested that the dOHnhi 11 side of the hi ghway . ., be considered, as an option that night be less expensive to develop, while avoiding the hillside soil prob1el.1s" Responses favored an a1ignl.1ent adjacent to the hi yh\lay because of: 10\ler-cost constructi on and r.l2i ntenance, ease of access, r.linil.lal \Ii1dl ife ir.1pacts, and the value of confining visual inpacts to a corridor already developed for public use.

. ..

.

. .

. ..,

( (

Forest Service Consideration -- The uphill side of the "highway was the original and preferred route thl"ough National Forest lands on Hitkof Island. The short section of line between the Three Lakes Loop Road and the Blind Slough clearcut was relocated onto the grass flats only because of severe and unmanageable soil-stability problems along 65-75 percent of this po\~erline corridor. Although power1ines and towers could be designed to withstand any mass movement of soil and debris, the construction and clearing necessary for structural safety would virtually assure accelerated erosion and mass soil failure along the entire forested portion of the hillside. Timber along this slope is not considered available for commercial harvest by standard clearcut methods because of oV2rst2epene slopes and unstable soils; however, power1ine construction would require right-of-way clearing sir.!i1ar to c1earcut timber harvest, removing the only measure of soil stability nO\'1 present on these slopes. (A similar problem of oversteepened slopes and unstable soils exists along the north side of the Bradfield Canal, the location originally proposed for the first section of the Tyee transmission line from the po',;erhouse to Hrangell Island. It \'/aS necessary to relocate this entire section of transmission line to the south side of Bradfield Canal because of soil-stability problems.) Although the highway route was re-examined along with the other alternative alignments, Forest Service staff officers remain unwilling to recommend this hillside location because of the natural instability of the slope and the lack of any effective means to mitigate the problem. Only the uphill section already harvested {between Man-made Hole and the Three Lakes Loop Road} would be suitable for power1ine construction.

ALTERNATIVE 2 (Blind River Grass Flats) Public Comment -- Responses were sharply divided between those who feared

severe impacts to wildlife and waterfowl, especially bird strikes on towers and lines, and those who felt mitigation measures were available to make potential impacts negligible. Those strongly opposed to the route cited the unique, diverse. and fragile nature of the area; potential for eagle, trumpeter swan and other waterfowl collisions with transmission lines; and the visual and esthetic impacts of development in the pristine environment of the grass flats. Respondents ~/ho strongly supported the grass flats route cited 10\~er development costs (tne route has already been surveyed and designed) and minimal resource conflicts due to Pl"oposed location and design requirements that would effectively minimize visual and wildlife impacts.

Forest Service Consideration -- While recognizing the unique wildlife and recreation values of the Blind River grass flats, Forest Service staff officers felt there were better opportunities to effectively mitigate anticipated impacts in the grass flats than along either of the other alternative routes. How2ver, this was by far the most controversial of the alternatives considered, because of its unique habitat features, and its value and prominence as a recreation area for local residents. Analysis of public comment on the grass flats route indicates that more than half the respondents would consider the physical presence of the I powerline a major. irreversible impact, regardless of powerline location and design, or the effectiveness of mitigative measures. (Nearly 20 years ago, when the highway was build through this area, the original route proposed was almost identical to

-2-

-. .

!~J

( ( the Alternative 2 powerline route. Federal, state, and local officials, along with local residents agreed at that time to locate the highway off the grass flats and onto the toe of the mountain slope to preserve the wildlife and recreation values of the grass flats.)

ALTERi!ATIVE 3 (Ridge Route) Public Comment -- A majority of comments rejected the ridge route as having

unacceptably high development and maintenance costs which would add to already huge project cost overruns, all of which would have to be paid by the consumer. Most who favored or would accept a ridge alternative suggested further study of a modified ridge route that would connect back to the original highway alignment near the Crystal Lake Pm'/er Plant. Respondents favoring the ridge route stressed the value of avoiding the grass flats, rather than any values associated with the ridge alignment itself.

Forest Service Consideration -- The ridge route would incur high development costs, require special equipment to access and maintain, and pose \Jind damage and ice-loading problems that could significantly raise annual maintenance costs. Opportunities to mitigate these impacts are limited. In addition, Forest Service wildlife biologists see this route as bisecting an important wildlife range used extensively by deer, bear, grouse, and furbearers. Timbered areas on the upper slopes are used by deer in winter as well as summer. This is not as emotional a wildlife issue as that represented by the flats alternative, because the area is relatively inaccessible to most recreationists. However, development of a ridge-line pOl'/er corridor would open the area to more intensive use, both surrmer and \;int!:r. Selection of the ridge route would also require the development of a separate right-of-way for Crystal Lake power a distance of about 3.5 miles toward town until the ridge route descended back to the highway right-of-way. The proposal to modify the ridge route, returning to the preferred alignment near the Crystal Lake Hydro Plant, was also examined by Forest Service specialists. If feasible, this modification would at least allow power from the two sources to share the same right-of-way toward town. However, the shortened route wou1d not eliminate any of the impacts associated with the ridge route alternative, it would simply ~hange th!:ir magnitude and order of importance. For example: while the shortened route would reduce impacts to the high country \lildlife area, it \'Iould introduce serious soil stability and wind hazard problems in its descent toward Blind Slough.

GENERAL ANALYSIS AND RECOit\lENDATION

PUBLIC CONCERNS ArlO PREFERENCES The weight of public preference leaned strongly toward the original alignment

on the uphill side of Mitkof Highway. However, most of these respondents seemed una\,/are of the magnitude of the slope and soils problem, chose to ignore it, or assumed it was simply an engineering problem that could easily be resolved. A few respondents, acknowledging the difficulties inherent in the uphill alignment, " nevertheless recorrrnended development as close to the high\oJay as possible, whichever side of the roadway was most feasible and least expensive. Development of the

-3-

...

( ( transmission line on the lower side of the roadway would avoid direct impacts to both the grass flats and the hillside. Ho:J2Ver, such an alignment \'/ould result in a more prominent visual impact along the highway. ~hile some respondents stated that this visual impact would be an acceptable tradeoff in order to preserve more highly regarded values in the grass flats, it can.be assumed that others would object to any development that tends to diminish the quality of the existing recreation experience in this area.

STAFF DELI BERATI ONS AND RECQi1t1EtWATION After considering inputs from all sources, both \lithin and outside the agency,

staff officers and resource specialists were unable to accept or recommend to the Forest Supervisor either Alternative 1 or Alternative 3, because the anticipated impacts cannot be satisfactorily mitigated.

Alternative 2 is preferred by staff because, in their opinion, the anticipated impacts can be reduced to an acceptable level. However, the Forest Supervisor and staff also recognize the strong concerns for preservation of the flats, expressed in the majority of public ,responses received. Analysis of these responses indicates that those opposed to the grass flats route would not accept any degree of mitigation as sufficient protection for the existing fish, wild1ife, and recreation values; and that the presence of the line itself would be an unacceptable impact.

In effect, this situation left the decisionmaker with three alternatives with associated physical, biological, financial, and social impacts that could not be satisfactorily resolved.

However, earlier in the field investigation for this section of right-of-way, specialists from a variety of disciplines examined the dmmhill side of the roao',Jay as a possible alternative. At that time the group agreed that visual im~acts wculd be too severe, and they turned their attention to other options. Now, through this review process, several individuals and groups have indicated that the downhill option should be examined as a viable alternative.

Staff review of this option, in conjunction with the easterly portion of the uphill route, suggested a compromise alignment that might be more acceptable to all interested parties. While reluctant to recommend this route because (f the visual impact along the grass-flats side of the roadway, the staff nevertheless acknowledged that this compromise alternative would significantly reduce the direct impacts to wildlife in the flats, and to the unstable soils on the uphill side of the roadway. Taking advantage of stable soils in the clearcut on the uphill side, an alignment could be developed that would impact only the western two-thirds of the grass flats side, \thile avoiding any direct impacts to the f1an-made Hole area and the wetlands surrounding it.

On March 15, the Forest Supervisor, in consultation with staff officers, selected this alternative alignment as an acceptable compromise which should be cost effective through the life of the project, while protecting the valuable and fragile resources of the area. ~o action will be taken prior to 45 days fro~ the, date of this decision.

-4-

APPENDIX D FOUNDATION DRAWINGS

(SELECTED)

...

10828

E

o

c

UL TlMAT'E DESIGN LOAD

STRUCTURE TYPE STX - E 10 B 1--::~-----4--r-----1

STRUCTURE ATTACHMENT HT. COMPRESSION HORIZONTAL SHEAR UPLIFT

5' 8'

29k 29 k

2 3 EXHIBIT 0-14

"

ALTERNATE

NOTES: 1. TSF -6A IS AN ALTERNATE TO FOOTI NG

2.

3.

TYPE TSF-6 AND IS ONLY INTENDED FOR USE IN CONJUNCTION WITH THE STX-E10 TOWER TYPE IN AREAS OF SHALLOW MUSKEG ON MITKOF ISLAND.

INSTALLATION SHALL CONFORM TO TECHNICAL SPECIFICATIONS OF CON-TRACT DOCUMENTS NO. 2708-8 UNLESS OTHERWISE NOTED.

BOTH PILES SHALL BE DRIVEN TO REFUSAL OR AS DIRECTED BY THE FIELD ENGINEER.

4. THE BATTERED PILE SHALL BE LOCATED OUTSIDE THE TOWER LEGS.

DRIVEN PLE ALTERNATE TSF-6A

t-+-__ t-_____ --1-_+---1-_~~~~~Project K HYD CTRIC p~OJECT NO, REV, 138 KV TRANSMISSION L.N: 2145 1

A.P.A DRAWING NO, 2708-TS-115 Client

,~

r~!

--,.---- --fa-, ,

.

ID .' N

'-, A

ULTIMATE DESIGN LOAO I LEG STRUCTURE' TANGENT

TYPE STRUCTURE 2'6" AT~CHMENT HGT.

COMPRESSION 33 k

NOTE:

I.

2.

ONE UNIT CONSISTS OF 12'-6" OF 8BP36 WITH 18 II X 18" X 3 i 4 S TEE L PLATE WELDED ON END

FOUNDATION SHALL BE INSTALLED IN UNDISTURBED SOIL.

3. THIS FOUNDATION IS TO BE USED ONLY WITH STX- E 10 TOWER TYPE

I-------+---+---+---+--;----~I- -- I 1" .. HORIZONTAL Ilk '2. I;;,/'~!e~ ~~~ Dvo/6,

SHEAR 1 11/30/82 DeSIGN LOADS PEO CHSlR~ UPLIFT 45 k REV. DATE DESCRIPTION BY APP'D

STEEL PILING FOUNDATION ~~~~~~~!J~~~!!.~~INEE.UNG COMPAN" FOR NON-S~BMERGED AND NON -SOLID

ROBERT W RETHERFORD ASSOCIATES OIVISION ROCK SOIL CONDIT IONS OWN. BY b. O. GRANT SCALE 1/2": 1'- Q" CKO. BY O. BURLINGAME w.O. No. ______ _ DATE SEPT. 3Q. 1982

TSF-7 DRAWING

No. 2708TS112

E

-

-

D

-

c

-

B

-

....

A

lI0II28

oJ :

:J: ~ CI Z "-I oJ oJ :! o ~

z i

I 2

{LEG BRACKET

7 J , CD

,

N

,GRD. SURFACE

IrHfH' J MUSKEG OR VI NON BEARING

~ SOIL.) ~ .-/ c ~ili , ~~ : (ii ~~...,~~;.~ ...... "'""1. ' .... ' .... ~~~\\ r'~v ~::. ::: ~.:."."~ FIRM BEARING

'.~.. . :;~.I SOIL. .... .. . ".1

I 0 ::~.... I - rr- r-- I o I

z :::I

I I I I

. I .' .: . I . . ~'; I

3 I

ULTIMATE DESIGN MIN. LOADS (KIPS) L

MUSKEG ATTACH MIN.j DEPTH HEIGHT EMB.:

( FT.) A ( F T. ) C D II COMPRESSION: 33 K HORll. SHEAR : I I K UPL.IFT = 45 K

NOTES:

16' 3' - 6" 19' 5' - 6" 22' 7'-6" 25' 9'-6"

6' 10' e' II' 10' 12' 13'

I. MATERIAL CONSISTS OF LENGTH "L" OF HP 14 a 89 WITH 18"a 18". 3/4" STEEL PLATE WEL.DED ON END.

2. FOUNDATION SHALL BE INSTALLED IN UNDISTURBED SOIL.

3. THIS FOUNDATION IS TO BE USED ONLY WITH STX - E 10 TOWER TYPE.

411. LEG BRACKET FOR HP 14 a 89 P1LE MUST BE ORDERED FROM TOWER FABRICATOR OR MODIFIED IN FIELD TO SUIT.

- .;. ~r- EXCAVATE TO SUIT AND A. "' . 1 BACKFILL. WITH :J:

'. I COMPACTED MATERIAL .:;, I

. II --, .1 ."~'. .. ... 'i',' A ~. ;. I A

--L.-....I..-Ir. . :D . S I L.::.'-,"-"~ ___ oJ

1\ / V 3/8

I '- 1'- 6"SQ. II 3/4 "It

SECTION A-A RECORD CRAWl NG

ttlt TSF-7A INTERNATIONAL ENGINEERING COMPANY, INC. STEEL PILING FOUNDATION

~ "'JR" ',", ,'S,' COMPANY FOR NON- SUBMERGED AND NON - SOLI D ~~3C,~IC5T~INTR,'~b! 6410, ANCHORAGE, ALASKA 9M02 ~(t07)Z74.'551 ROCK SOIL CONDITIONS

APP'D. ALASKA POWER AUTHORITY 2708-TS-128 8Y CK'e APp'e DATE: 1-25-83

t-+-__ -+ ________ r---+--+--+O=-:E~S:_'_IG_:_N-. M~.T.~N;.;.._II"ro,.~ PROJECT NOIRev. OWN. L .C.J. TYEE LAKE TIL 2145"0 CK'D. COo... DRAWING NO.

NO. DATE REVISIONS

2 EXHIBIT D tV 3 I0I2l 1 I 1 -UPLIFT LIST OF MATERIALS

, 'HORIZ. S~EAR REQ'D. DESCRIPT ION ITEM !~OMPRESSION Hili. Section, DIXIE. (iJ 4 Pipe Anchor, DlXI~ 2)

I: Gr i lIoge Base I 01 XI~ >< 0 ~ , >< drilled for 11j2 "bolt ot center 3) ID -", LGROlMD SURFACE

: rTJT'# \ ,~n\\H)n ~) Anchor Cap DIXIe." 4) ~ ~ "SEE TABLE Pipe e. tensions - see table 5) % AT BOTTO .. (!) ~I -

~ -4 ~KEG OR z I&J = ~ %

o

0 NQN- BEARING !Il SOIL, ;~ t 1 (C(. f(HW f(, l{t40HS~S\t,\ C!) II \\~ ,.y ' .... ...",-r 1tIt!,]fi

'. Z ~ ;::. ~RM BEARING -:I 'II: 3: =0

, SOIL 1 c:t -'II: ~ a::

z c - i 03w SCHEDULE 80 :

APPENDIX E GUY ANCHOR DRAWINGS

(SELECTED)

------.. :--

EXHIBIT E-l

BE-AfZ I tJ9 '?Ol L.. E:.QUIVALf:..~f t::.A~IH ~U~~HA~~E:. ~ ItJ P0f Of M LJ ?KE;.6j. AND P!:;;A1 C:::::OVE-~ LAYE::-tZ,? D~pfH TYPE:- 100 200 300 400 500 foOD "'e" (}:20 0 101-0" 9 '-(011 9 1-011 8'-~" {3'-O ?'_(p"

I tJ FT. =2'5 8'-0" 7 1-(0" 7'-0" (p'-{p' {j)'-O (01-0 MINI- (/)=30 (01-0" (p'-o" ?'-u/' ,=,'-(0" ?'-O ?'-o MUM

'"---l!-~-~ ~E~~RD DRAWING - '.---~ -- If - '-".' ~,

- ~ I LJ?~ t.JA~~O~ 1~!:;,~C.H O~ '" - x-~ --7 I ~: ~oo PU"HE>t:? ItJfO I.OZ X

\:)I L~ I ~ 1 ~ --- - @ I{:.._-== c

,.... I I

~ ~ "'-.1 I )- ~ :r~1 'c T r. 1 * L-!:-~~"H VA~IEh f~OM MArE:-I(1AL.~ L-l~1 --s ~ A - (P',01B'1:1Yf'It:AI,..L.Y l.'f;.M t)f;J:;1C::: ~t ~ 11 OI.J RE:-Q'i:/. ---~ l:JJ-J 8' O~ 1 I. (l) 1!' X 12'A1J111KA ~ 1 >< I....06i (LJI.JT~E;A""f:.t/) (Z) ~ rJ,.,AH W(vttl 1 ,,~ ~~

'b~*- >< 4" L.OI'J~ ~ 1'-iP" MIY,I'lA"K flW- ~ A"I010~ 1(01/ 1 >< 11/4"> x to'CIyF.') MAI~~IAl,.. ~/ ~AVE; = IOOPc;,f 1 ~ ~"'ll"1ee:.~ ~IK~ 2 +,r- ~ , I'". ... ' \/'IIJ'I''1I , ." ~,

!~ ~ ~ \~ = 30 rc..f ::: 0 1" / I I ~ -E --~ -----_ . / I . ,(\ f'E::-Af I~ B~A~l~t1 ?OIL- LJ~rr rJ~14Hr I A~~ L..~ Of t .oi ~= CD~ f'Gf ~ ' 1S = fc..f tN1f.~t-JA[.... ~ " TYPE;. ffJ4 ""OIL .,j ~, -' t-1O 0 E-AAi E-L..-Y 100 = 20 \L!

-EXHIBIT E-2

APP~QV[u r.~~ 3'- O"!

COMPACTED r-ASREQ~l BACKFILL ~

"Y/M~W1f\--~r ,.~,,,,,,-K UNDISTURBED

SOIL

1 (TYP.)

o . , U)

./~~\-. ,,~ " SEE 5HE"ET ~ OF 2 FO~ I3AR~E.L A~G.HOR ~oDIFICA"'Ot-Js SQUARE NUT a WASHER~

(JAM THREADS)

ELEVATION VIEW

55 GALLON DRUM:----""" FILLED wI CONCRETE ""

-.----'~ I::':~~:'''''~': :~:~ .. :

+1

r.~ ~ ::. -', :;', \D , , .~. _,4.. ..,' , -f. _~ . 0.,1.,

~

APPENDIX F SHOEMAKER BAY-WRAI~GELL TIE LINE

B809/2145p0052:0148p

!IIWt:

-

.t~.

-

EXHIBIT F-l

SHOEMAKER BAY - WRANGELL 138 KV TRANSMISSION LINE

CONTRACT NO. 2708-11

BASIC DESIGN MANUAL

SCOPE AND GENERAL

The Shoemaker Bay - Wrangell single circuit tie line is rated at 138 kV and will be approximately 17,400 feet (3.30 miles) in length. Power will be transmitted from the Wrangell Switchyard of the Tyee Lake 138 kV Trans-mission System to the new substation inside the City of Wrangell which will have transformers rated at 10 MW. Initial operation of the tie line will be at 69 kV.

The attached vicinity map (Figure 1) shows the basic transmission line alignment, of which approximately one mile will be along the Zimovia Highway requiring the incorporation of an existing 7.2/12.5 kV distribu-tion line as underbuild construction. Figure 2 show the typical pole con-figurations for both sections.

APPLICABLE STANDARDS

All design and construction of the transmission line will conform to the minimum standards set forth by the National Electrical Safety Code (NESC) and the Rural Electrification Administration (REA) of the U.S. Department of Agriculture.

RIGHT-OF-WAY

The right-of-way width for the Shoemaker Bay - Wrangell Transmission Line will be 80 feet from the Wrangell Switchyard up to the Zimovia Highway and 40 feet along the highway where the distribution underbuild is incorporated into the line.

LINE LOADING CRITERIA

The transmission line will be deSigned for the following loading conditions:

o NESC Heavy Loading - ~" radial ice with 4 PSF wind at OOF and

o Extreme Wind - 21 PSF wind (90 mph) on bare conductors at 400 F

F-l

.....

....

-

' ..

-

-

MINIMUM SAFETY FACTORS

The transmission line will be designed to the following minimum safety factors:

Element of Line

Conductor, Splices and Fastenings

Wood Poles Transverse Strength (Wind) Transverse Strength (Wire tension) Vertical Strength longitudinal Strength (In general) longitudinal Strength (At deadends)

Guys and Guy Anchors Transverse Strength (Wind) Transverse Strength (Wire tension) longitudinal Strength (In general) longitudinal Strength (At deadends)

Insulators Cant i1 ever Compression Tension

Minimum Safety Factor

2.0

4.0 2.0 4.0 1. 33 2.0

2.67 1.5 1.0 1.5

2.5 2.0 2.0

line hardware will be compatible with the M&E ratings of the insulators used.

CLEARANCES

The following minimum conductor-to-2round clearances will be maintained:

o Over areas accessible to pedestrians only

o Over public streets and highways

19.1 feet at 120oF, final tension, bare conductors

24.1 feet at 120oF, final tension, bare conductors

Minimum phase separations and clearances to guy wires required by NESC will also be maintained.

F-2

CONDUCTOR SELECTION

The characteristics of the conductors to be used are:

For 138 kV Transmission

o Code Name - Dove/AW o Type - Aluminum, Aluminum-Clad, Steel Reinforced (ACSR/AW) o Size - 556.5 Kcmil o Diameter - 0.927 Inch o Rated Ultimate Tensile Strength - 21,900 Lbs. o Stranding Ratio - 26/7

For 7.2/12/5 kV Distribution Underbuild

o Code Name - Raven o Type - Aluminum Conductor, Steel Reinforced (ACSR) o Size - 1/0 o Diameter - 0.398 Inch o Rated Ultimate Tensile Strength - 4,380 Lbs. o Stranding Ratio - 6/1

Limiting tension for the Dove/AW conductor will be 10 percent of UTS under everyday loading conditions. This will permit the use of excess owner-furnished suspension insulators (15,000 lb. M&E rating) from the Tyee Lake Transmission System Construction Contract at an estimated cost savings of $5,000. Due to the reduced tension, vibration dampers will not be required for vibration protection. The estimated cost savings is approximately $30.000. The neutral conductor of the distribution underbuild will be grounded at every pole.

WOOD POLES

Class Hl through Class H4 pressure-treated Douglas Fir wood poles will be used. Overall pole length will vary between 40 and 85 feet as dictated by terrain or clearance considerations.

Standard pole embedment will be 10% of the pole length plus two feet. A reduced embedment will be used where poles are set in solid rock.

F-3

-""

DISTRIBUTION UNDERBUILD CONSTRUCTION

All existing poles along the underbuild section of the line will be re-placed. Existing span lengths will be maintained to the extent possible to facilitate the transfer of existing services.

New pole-top assemblies and conductors for the 7.2/12.5 kV primary dis-tribution will be provided under Contract 2708-11. Transfer of all second-ary distribution, service drops, transformers, meters, street lights, etc., onto the new poles will be provided by the City of Wrangell. All mater-ials salvaged from the existing line will remain the property of the City of Wrangell.

All construction work along the Zimovia Highway will be carefully coordi-nated with the City of Wrangell and the telephone and Cable TV utilities to prevent or minimize interruptions of existing services.

F-4 RPVjTM - March 1983

~!:,-OJ!'1~\Kf'LBAY - W~N0rL~_1}_KJ_T_Ri\N_S_M)_S_SJON_L~~E_ YJ _C} _NJ!Y __ MAp_

FIGURE 1

~; t -to '"-'

"

-. Ft?5T It-e"'-ATOR (TYP.)

, :I: ~

t- ~i :r \!) ~ -w

-

.:t: ~ W \91 -l

-EXHIBIT F-2, Sheet 1

SHOEMAKER BAY - WRANGELL 138 KV TRANSMISSION LINE

DETERMINATION OF RIGHT-OF-WAY WIDTH REQUIREMENTS

I. Wrangell Switchyard to PI-4 (State of Alaska Lands) Maximum Span - 600 Feet Conductor - 556.5 kcmil ACSR (Dove) A. Case I - 6 PSF Wind on Bare Conductor @ 600 F

.

':: :: I

~__ 43::2 Ft. J . Right-of-Way Width

B. Case II - Extreme Wind Condition (21 PSF)

51

/1,,'// "I'~ ~., .

. '. I ~ 80 Ft. .. Ri ght-of-Way .

Width

~ = Conductor Swing Angle Under 6 PSF Wind @ 600 F

= 31. 180

Sf = Conductor Final Sag With 6 PSF Wind @ 600 F

= 15.64 Feet

x = Minimum Reauired Clearance to Edge of Right-of-Way

= 7.1 Feet

y = Total Horizontal Distance From Conductor Attachment Point to Edge of Right-of-Way

= 16.6 Feet

~ = Conductor Swing Angle Under Extreme Wind (21 PSF)

= 64.720

Sf = Conductor Final Sag Under Extreme Wind (21 PSF)

= 16.53 Feet

USE 80 FEET RIGHT-OF-WAY WIDTH Page 1 of 2

EXHIBIT F-2. Sheet 2

SHOEMAKER BAY - WRANGELL 138 KV TRANSMISSION LINE

DETERMINATION OF RIGHT-OF-WAY WIDTH REQUIREMENTS

II. PI-4 to Wrangell Substation (Zimovia Highway) Maximum Span - 325 Feet Conductor - 556.5 kcmil ACSR (Dove) A. Case I - 6 PSF Wind on Bare Conductor @ 600 F

~r~ I I

i

1- .1 I Right-of-Way Width

B. Case II - Extreme Wind Condition (21 PSF)

51

I. ~ .':,~ .'~f" :.::-r i::.." / .... ' ~

36:-2 Ft. Right-of-Way

Width

~ = Conductor Swing Angle Under 6 PSF Wind @ 600 F

= 31.180

Sf = Conductor Final Sag With -6 PSF Wind @ 600 F

= 7.89 Feet

x = Minimum Required Clearance to Edge of Right-of-Way

= 7.1 Feet

y = Total Horizontal Distance From Conductor Attachment Point to Edge of Right-of-Way

= 11. 9 Feet

~ = Conductor Swing Angle Under Extreme Wind (21 PSF)

= 64.720

Sf = Conductor Final Saq Under Extreme Wind (21 PSF)

= 6.19 Feet

USE 40 FEET RIGHT-OF-WAY WIDTH Page 2 of 2

APPENDIX G

BASIC DESIGN MANUAL

BASIC DESIGN MANUAL TYEE LAKE HYDROELECTRIC PROJECT

138 KV TRANSMISSION LINE PETERSBURG AND WRANGELL, ALASKA

Project Number 2708

Prepared By: Robert W. Retherford Associates Division International Engineerin~ Company, Inc.

P.O. Box 6410, 813 0" Street Anchorage, Alaska 99502

NOVEMBER 1981

CONTENTS CHAPTER

Abbreviations

1: Introduction

1.1 Purpose and Scope of Report

2. Summary Data

2.1 Description of Transmission Line Route 2.2 Description of Tower Structures 2.3 Transmission Line Design Data Summary

3. Basic REA and NESC Requirements

3.1 Outline of Requirements

4. ~ine Design Technical Analysis

4.1 Conductor Loading, Sag and Tension 4.2 Insulators 4.3 Insulator Clearance and Swing 4.4 Tower Body Maximum Loading Graph 4.5 Footings 4.6 Anchors 4.7 Guying Requirements 4.8 Conductor Vibration Control 4.9 Submarine Cable and Terminals

5. Sample Calculations

5.1 Calculations Used in Fundamental Design

i

PAGE

1-1

2-1 2-6 2-11

3-1

4-1 4-7 4-9 4-15 4-19 4-21 4-22 4-24 4-28

5-1

....

-

..

DRAWINGS

Drawing Chapter 2 Drawings

2-1 Vicinity Map Tyee Lake Project Transmission System 2-3 2-2 Typical Single Pole 138 kV Post Type Insulators, HPT-1B 2-8 2-2 138 kV Guyed X Tower (Tangent) 2-9 2-4 Long Span Structure Conceptual Design 2-10

Chapter 4 Drawings

4-1 Angle vs Sum of Spans (Dahlia) 4-2 STX-E Insulator Swing Clearances 4-3 Insulator Swing Chart, Dove, 1320 1 R.S. '4-4 Insulator Swing Chart, 37#8 AW, 8000 1 R.S. 4-5 Insulator Swing Chart, 1200 Equivalent 4-6 Tower (STX) Selection Graph - "Dove" Conductor 4-7 :rower (STX) Selection Graph - 37#8 AW Conductor' 4-8 Guying Arrangements for Suspension Type Structures 4-9 Tension - Percent of Ultimate Strength, ACSR Lines

Without Armor Rods or Dampers 4-10 Tension - Percent of Utlimate Strength, ACSR LInes

Protected With Armor Rods. 4-11 Tension - Percent of Ultimate Strength, ACSR Lines

4-8 4-11 4-12 4-13 4-14 4-17 4-18 4-23

4-25

4-26

Protected by Stockbridge Dampers 4-27 4-12 138 kV Submarine Cable Terminal General Arrangement 4-29

Chapter 5 Drawj n~

5-1 Single Loop Galloping Analysis for HPT-IB Structure 5-11 5-2 Double Loop Galloping Analysis for Guyed X Tower 5-14

i i

"-

TABLES

Table Chapter 2 Tables

2-1 Conductor, Structure, and Submarine Cable Locations' 2-4 2-2 Transmission Line Design Data Summary - Conductor: "Dahlia" 2-12 2-3 Transmission Line Design Data Summary - Conductor: "Dove ll 2-14 2-4 Transmi s's ion Line Design Data Summary - Conductor: 37#8 AW 2-16

Chapter 3 Tables

3-1 Clearances (in inches) in Any Direction From Line Conductors to Supports and Guy Wires Attached to the Same Support. 3-2

3-2 Recommended Minimum Vertical Clearances (in feet) Above Ground or Rails for Spotting Structures on Plan or Profile Sheets 3-3

3-3 Crossing Clearances (in feet) Of Wires Carried on -=Oi fferent Supports 3-4

3-4 Overload Capacity Factors for Wood Structures 3-5

Chapter 4 Tables

4-1 Transmission Line Desing Criteria by Line Section 4-2 Conductor Characteristics 4-3 Conductor Loading/Tension Data 4-4 Ruling Span Data - Sag and Tension

iii

4-2 4-3 4-4 4-6

APPENDIX

A-I A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-I0 A-II

-

B-1 B-2 B-3 B-4

C-l C-2 C-3

C-4

APPENDICES

APPENDIX A - EXHIBITS

TA-2 Rock Anchor Assembly TA-3 Steel Plate Anchor Assembly TA-5-8 Multiple Helix Anchor TSF-l Footing TSF-IA Footing TSF-2 Footing TSF-2A Footing TSF-3 Footing TSF-4 Footing TSF-5 Footing Transmission Line Vibration Dampers

APPENDIX B - EXHIBITS

SAG Template Basic Equations SAG Template Coordinates - Dahlia SAG Template Coordinates - Dove SAG Template Coordinates - 37#8 AW

. APPENDIX C - EXHIBITS

STX-E 138 kV Guyed Tower (tangent) STn-E 138 kV Guyed Tower Long Span (tangent) ST3-El1 138 kV Guyed Column Small Angle

Structure O~-27~ ST3-EI2 138 kV Guyed Column Medium Angle

Structure 27~ - 48~ iv

PAGE

A-I A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-lO A-ll

B-1 B-2 B-3 B-4

C-1 C-2

C-3

C-4

APPENDICES (Cont'd)

-

-

APPENDIX : PAGE -

C-5 ST3-EI3 138 kV Guyed Column Large Angle .'oi",

Structure 48 - 90~ C-5 C-6 ST3-EI4 and E15 138 kV Guyed Column Deadend

Tangent Structure C-6 C-7 ST3-E51 138 kV Guyed Column Small Angle

Structure O~ - 27 C-7 C-8 ST3-E52 138 kV Guyed Column Medium Angle

Structure 27 - 48 C-8 C-9 ST3-E53 138 kV Guyed Column Large Angle

Structure 48~ - 90 C-9 C-I0 ST3-E54 and E55 138 kV Guyed Column Deadend

-Tangent Structure C-I0

v

ABBREVIATIONS/SYMBOLS

A AMPERES ACSR ALUMINUM CONDUCTOR, STEEL-REINFORCED AW ALUMOWELD ~

'?F DEGREES FAHRENHEIT FT FEET "'~1

FT2 SQUARE FEET Hp HORSEPOWER In. INCHES K PREFIX MULTIPLIER (xIOOO) - METRIC KCM THOUSAND CIRCULAR MILS kV KILOVOLTS kW KILOWATTS kVA KILOVOLTAMPERES 1 b. POUNDS L. F. LINEAR FEET M

-MULTIPLIER (xIOOG) - ENGLISH

Max. MAXIMUM Min. MINIMUM Mi. MILES MVA MEGAVOLT - AMPERES MW MEGAWATTS OCB OIL CIRCUIT BREAKER PSI POUNDS PER SQUARE INCH R.S. RULING SPAN Sq. In. SQUARE INCH U.S. ULTIMATE STRENGTH UTS ULTIMATE TENSILE STRENGTH Yr YEAR

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CHAPTER 1

INTRODUCTION

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3APA36/Ll

1.1 PURPOSE AND SCOPE OF REPORT

CHAPTER 1 INTRODUCTION

This design manual presents the recommended design criteria for the 138 KV Transmission Line between the Tyee Lake Hydroelectric Station and the communities of Wrangell and Petersburg.

The Tyee Hydroelectric Plant will provide 20,000 kilowatts of water turbine generation in its initial phase. Each generating unit will consist of a horizontal-axis, 13,800 HP Pelton-type impulse turbine, connected to a 10,000 kW generator. Thi s hydroe 1 ectri c power wi 11 replace the di ese 1 generators as the primary source of power for the combined Petersburg-Wrange 11 system. The di ese 1 generators wi 11 be retai ned as the secondat'y source of power within the system, making up power demand deficiencies, primarily at times of peak loads.

Thi~transmission line design is considered the most -satisfactory of the twelve alternative transmission systems investigated. 1

1 Transmission systems evaluation of conventional and unconventional configurations for interconnecting Petersburg, Wrangell and the Tyee Power Plant of the Tyee Lake Hydroelectric Project, International Engineering Company, Inc., Anchorage, Alaska, March 1981.

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CHAPTER 2

SUMMARY DATA

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2.1 DESCRIPTION OF TRANSMISSION LINE ROUTE

CHAPTER 2 SUMMARY DATA

Drawing 2-1, Vicinity Map Tyee Lake Project Transmission 5stem, displays the line route along Mitkof Island, Vank Island, Woronfski:Island, Wrangell Island and terminating at the Tyee Lake Power house.

The transmission line route traverses terrain that ranges from sea level to 1850 feet above sea level. The soil conditions include patches of muskeg swamp, silty and sandy layers of varying depths, and solid rock with and without overburden. Brush and densely located trees of western hemlock and Sitka spruce occur at each end of the route.

The transmission corridor has several access roads to limited parts of the line on Mitkof Island the transmission line parallels the main road to Blind Slough. Vank Island may provide some access via its established logging roads. Woronkofski Island has no access roads. Where the line tra~rses up the Bradfield Canal, logging roads provide limited access in two location. There is some poss'ibility of access by of!-the-road equipment in some locations, but for a substantial part of the line, the terrain is interrupted regularly by precipitous stream basins.

Helicopter construction is anticipated to be in portions of this project where ground based vehicles can't be staged. They will be used for shuttle of construction and line materials, personnel support, and for emergency medical evacuation.

The route includes 68.2 miles of overhead transmission circuit consisting of about 7.8 miles of 556.5 KCM all aluminum conductor (Dahlia). This will be on the single pole HPT-IB structures (Drawing 2-1). There will also be about 35.4 miles of 556.5 KCM ACSR (Dove) on hinged X-tower configeration (Drawing 2-2) and about 25 miles of high-strength 37 No.8 Alumoweld on IT structures (Drawing 2-3) for use on long spans.

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Completing the circuit is 12.6 miles of submarine cable in four sections of 4.1, 3.32, 3.09, and 2.08 miles. These submarine cables consist of 4 cables (3 operating wit~ one sp.are) of 500 KCM copper equivalent, lead covered, wire armored and places with separations of 300 1Q 600 feet in water depths up to about 150 fathoms (900 feet). -

A. Conductor and Structure Location

Table 2-1 is a summary of the type of construction, distance, and number of structures planned for the transmission line. These may be related directly to the vicinity map - Tyee Lake Transmission System, Drawing 2-1.

2-2

TYPE A DAHLIA TYPE .. DOVE

HPT WITH DI8TIIIUTION, ___ _ UNDER BUILT

X TOWER -'-'-'-'-

TYPE C 1T TOWER _ .. _ .. _ .. _ .. _ 37"" AW

2-3

ORAl l-1

INTERNATIONAL ENGINEERING CO, INC A MORRISON );NUDSEN COMf'ANl ROBERT W RETHERFORD ASSOCIATES DIVISION

TVIE LAK~ PROJECT T .. A etet IVITI ..

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TABLE 2-1 Sheet 1 of 2

."," Conductor, Structure, and Submarine Cable LocatiQns Overhead Portions

Iype of -Dlstance (Ml)/# -.

Island Location Miles Construction of Structures Mltkof Scow Bay to 7'6't'080 Wood Poles 4.32/78

TW'j n Creeks Dahlia Condo

Twin Creeks to 73 to 76 X-Tower 2.61/10 Falls Creek Dove Condo

Falls Creek to 70 to 73 Wood Pole 3.45/60 Big Gulch Dahlia Condo

Big Gulch to 59 to 70 X-Tower 11.12/52 Cable term. Dove Condo

VanF Cable term to 52 to 55 X-Tower 2.83/13 Cable term. Dove Condo

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Woronkofsi Cable Term. to 45 to 49 X-Tower 3.18/76 Cable Term. Dove Condo

Wrangell Cable term. to 38 to 42 X-tower 4.2/20 Angle #2 Dove Condo

Angle #2 to 33 to 38 7t -Tower 4.82/7 Angle #4 37#8 AW

Angle #4 to 30 to 33 X -Tower 3.04/12 STA 637 + 60 Dove Condo

STA 637 + 60 to 23 to 30 X/n-Tower 7.08/17 '"'~ STA 1011 + 50 37 #8 AW

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TABLE 2-1 Sheet 2 of 2

Conductor, Structure '. and Submari ne Cable Locations Overhead Portions --

-

Jype of D1 stance (~h )/# -

Island Location Miles Construction of Structures Wrangell SIA 1150 + 50 to 10 to 23 X-lower 4.52/22

Cable Term. Dove Condo

Cleve- Cable Term to 14 to 17 X-Tower 3.91/18 land Angle #15 Dove Cond Peninsula

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Angle #15 to 2 to 14 IT Tower 11. 7/21 Angle #22 37 #8 AW

"''' Angle #22 to 1 to 2 X-Tower 1.4/6 Tyee Substation 37 #8 AW

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Submarine Portion

,~iI Location Mile Distance --

Sumner Strait 55 to 59 4.1 Stikine Strait 49 to 52 3.32 Zimovia Strait 42 to 45 3.09 Bradfield Canal 17 to 19 2.08

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2.2 Description of Tower Structures

The basic structure designs have evolved from proven design techniques in Alaska and elsewhere and havE demonstrated cost savings_and reliable operating records. There will be three basic types of tow~rs proposed. Drawing 2-1 shows the various segments of line using different structures. The three different types of towers are listed below.

A. HPT - 1a Structure

This type of tower ;s shown on drawing 2-2 and is used quite extensively where the line passes through a population center, such as the line section south of Petersburg which follows the Mitkof Highway. This will also accommodate on the same structure some of the existing powerline in the same area. This post insulator, single wooden pole structure will be designed to accommodate underbuild of a distribution circuit and commu-nication cable. The construction will be "skip-span ll in nature with 300 to 360 foot spans of transmission overbuild with 150 to 180 foot spans of undel'build. The conductor on this portion will be all aluminum IIDahlia" at modest tensions to minimize guying requirements.

B. Guyed X-Towers

These type of towers have been used quite satisfactorily in Alaska before. Drawing 2-3 shows the basic tower. The transmission line continuing to Blind Slough changes to this guyed hinged X-tower with ACSR, IIDove ll , 556.5 KCM conductor with an estimated ruling span of 1320 feet. Similar overhead line configurations are used for all remaining lines to the powerhouse, except for approximately 20 miles of high strength conductor crossings or where submarine crossings are involved.

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C. Guyed n-Towers

Drawing 2-4 shows these.special towers suitable for long span con-s~ruction. There are three sections of long span constr~ction with these towers; two on Wrangell Island and one along Bradfi.e1d Canal. Special high strength conductor, 37#8 Alumoweld, is used for these long spans which are estimated to be 3,500 feet average and with some spans long as 8000 feet.

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HPT-IB ASSEMBLY

POLE TOP ( :

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138KVBOTTOM .... ".~ PHASE I TI(1H II

(I> om ~ 24.9 KV

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33'-6'

I 271-6"

211-0" ,

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, GROUND LEVEL

I I ~ I BASIC POLE - 65' CLASS 1

a'-6" I I DOUGLAS FIR I , I CIRCUMFERENCE: I

+ I TOP = 27" I GROUND LINE = 48.5 " L ...!

INTERr'~ATIONAL ENGINEERING COMPANY, INC

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TYEE LAKE PROJECT TYPICAL SINGLE POLE 138 KV

POST TYPE INSULATORS

DRAWING 2-a

l1'-O" I 9'-0" ~ --r--__ -r-_I I I

50'-0" TO

80'-0"

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21'-0"

29'-0" TO

59'-0"

TYEE LAKE PROJECT 138 KV GUYED X TOWER

( TANGENT)

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50'-0" TO

60'-0"

29'- 4"

25'-0"

THIS TYPE OF STRU:::TU--E ____ 1...\ BE CQr~5--~~._.:CT~D 1':' :"'CC~_:'/V='

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25'-0"

TYEE LAKE PROJECT LONG SPAN STRUCTURE

CONCEPTUAL DESIGN STlI-E

2-10

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