Asce 48-05 Design Of Steel Transmission Pole Structures.pdf

ASCE STANDARD

A5CE/5EI 48-05

American Society of Civil Engineers

Design of Steel Transmission Pole Structures This document uses both \.he Intel'national System o r Un it.s (Sf) and customary units.

ASCE

."--"-'-

$"uc""~I~~I .. m",•

Publtshed by the American Society of Civil Engineers

Lihrary of COIl~n.'SS

Ca l~lIogillg-i ll - I 'uhlicn li o n

D;II\I

Magee, WiJl iam L Design of stcel Ir.lI1smi,sioll polc ~lruClur<.'~ I William L. Magee:. p. em. ISBN 0-7844-0837·8 I. Electric linc~- I)ol cs and low<.'rs-D<.'~ i gn und e{ln~l rueti()n. 2. Steel, Strucluml. I. Till.:!.

T KJ242.D472006 62 1.3 19'22-de22 2()OO()O..lJ65 Pub lish..:d by American Society ofCiyil 1801 Alcx'lOder Bell Drih' Reston. Vif'61nia 20191 www.pubs.ascc.org

Engmee~

Any MntemenlS expressed in these mnterillh arc those of the indi .. idu;11 authors arld do not IlCccss;Irily rcpre~nt the vicw, of ASCE. which tal es no rt'spon~ib lI IlY for any M:ItCmcnt mad.: herein. No reference made in Ihi .. publi..-atio n It) any "'1X.'Ciric m..:lhod. pro(iuCI. procc.\\. or '\Cry icc con~titule.s or imphc:. an cnOO-.;cment. rt."COIl1mend:!tion. or wurronty thereof by ASCE.

or

ASCI:: makes no represenlalton or wlIrrn nty any kmd . whether C)lpres.s or implied. eoncemmg the ;tecumcy. complcte ness. ~\lltabil­ ity. or utility of any infol'llllition. app .. rutu~. product, or proct::.s uiscussed in Ihis publication. and a.,sumcs no liability therefore. Thi~ information should not be u..c d withoul Fir~1 sec urill!! cO!ll['ll'lenl ;nlvice with rc.'ptl·t 10 ilS .,ui1:tbil ilY for any !:encl':1 1or spccilir.: lIpp li cation. Anyonc utilizing this inform;l1ion aS~llIncs all li nhility ari,ill!: frum ~ur.:h usc. inr.:ludill!: but not limiled tu intrinJ;crncnt of lilly patenl or pat('nL~. ASCE and American S(lci~'IY of Ciyil EnSIIll'Cf,>-ReJ;i\h.:rcd in U.S. Patent and Trademarl Office. />I!(IIQCOIItt'S and "'lmI1H. You e;m ohtai n il1~tanl penlliS!;ion (() phOliX.'Opy ASCi: publicalion~ by usinJ; ASCE', onlinc I""nll i ~~ iOfl

service (w",·w.pubs.lISl'C.orglauthorvR igh...,lin l WckomeP"ge ht ml ,. Requl'S's fOf bull cop)'in~ of 100 copie.-. or more should be subnUltcd to Ihc R('prnlL~ Department. I'ubhcalioll<' Division, ASCE (addre.o-.s above): emai l: pemlis.sions(ibsce.o~. A rcprint order form can h..' lound at hllp: IIwww.pubs.ascc.org/authors/rcprillls.htl1ll Copyright f) '2006 by the Americ.m Society of Civil EnglllCCfli. All Righi:. Rc.~rv('d. ISBN 07844-08-'7·8 MnnufaclUl\'d in the United Slntcs of Amcrica.

STANDARDS In April 1980. the BOilfu of D,rection approved ASCE RuJe~ for Sl;mdards Commiuees [0 govem the writ-

ing
or reaffirmed by the "amo.:

proccs~

at imcfvah

nOI exceeding 5 year:;.

The following Stundards h:we been

i s~ucd:

ANS I/ASCE 1-82 N-72.."i Guideline for Design and Analysi ... fir Nuclear SafelY Related Eilnh Structures ANS I/ASCE 2-9 1 Measurement of Oxygen Tr:m\th in Ckllll Wmer ANS I/ASCE J-tH SwndanJ for the Stl'Uctuml Dc~ign of Compo~itc Slabs and ANSIIASCE 9-91 Standard P,~.ctice for thc Con\tructiol1 nnd I n~p..:etion of Compo\itc SI:lbs ASCE 4-98 Sci,mie Analy~i!'> of Safety-R.:lmcu Nuclear Strueturc~

Building Codc R('quircmcnts for Ma~onry Structurc~ (AC I 530-02lASCE 5-02ITMS 402-02) and Spceilicmitl11\ fur Ma~on ry Strtletures (ACI 530,102lASCE 6-02ITMS 602-(2) ASCElSEI 7-05 Mmi1lluIl1 Design Lo::tch for Building' :md Other Structurc), ANSIIASCE 8-90 St:mdard Specification for Ihe Dc~lgn ufCold-Funw:d S\;lintc~s Steel Structlll,ll Member\ AN$ I/ASCE 9-9J listed wit h ASCE 3-91 ASCE I0-97 De~ign of L:lItieed Steel Tnm\mi\sion StructufCS SEIIASCE I J-lJ9 Gu ideline for Structuml Condition As~c~~lllcnt uf Exhling Building~ ASCE 12-05 GUlddine~ for the Design of Urban Sub~ul1""ce Dr::tinage ASCE 13-05 Slilndnrd Guidelines for In\tallation of Urban Subsurface Dminnge ASCE 14-05 Slilndard Guidelincs forOpcration and Maultcnance of Urban Sub~urf;tce Drainage ASCE 1:'i-98 Standard PrJeticc for Direct Design of Buried Prcca~t Concrete Pipc Using St:lndard Instal];uions (SIDD) ASCE 16-95 Standard for Load Resistance Pactor Dc~ign (LRFD) of Enginee,rcd Wood Con~truction ASCE 17-96Air-Supponed Stnu:ture~ ASCE IlP)6 Standm'd Guidelines for In -Proces~ Oxygen Tr;IIl~fer Tc~ting

ASCE 19-96 Strth.:tural Applic:ttion ~ of StN'1 Cabk~ for Buildings

ASCE 20-96 St;ll1dard Guidelines for the Dc~ign and Inst;l llation of Pi le Foumlmion .. A$CE 21-96 Automated People Mover St:tndanh- P:ln I ASCE 21-1)8 Automated People Muver Standard ~- Pan 2 ASCE :! 1-00 Automated Pcople Movcr Staml;lrds- Part 3 SEI/ASCE 23-97 Specification for StructurnJ Steel Be:l1m with Web Openings ASCElSEJ 24-05 Rood Rcsislalll DeSIgn :lIlel Construl'tion ASCE 25-97 Eanh4uakc-Actuated Automatic Gas ShutOtT Devices ASCE 26-97 Standitrd Pr:tcticc for Design of Buril::d Precast Concrete Box Sectinn\ ASCE 27-00 Standard Pr:tctice fi.)T Dircct [)c\ign 0 1 Precast Concrete Pipe for Jacking in Trenchlc,s ConSlnl('tIOl1 ASCE 28-00 SUllidard PrJct;cc fo r Direct [)c~ i gn of Precast Concretl' Box Section, for Jacking in TrcnchJcs~ Con~tructi(ln

SEIIASCElSFPE 29-99 Standard Cakulatiol1 MethlXb for $rmc(ural Pire ProteCTion SEIIASCE 3U-OO Guidclinc for Condition A~~e.,s mellt of thc Bui lding Envelope SEll ASCE 31-03 Seismic Evalu:uion of Existing, l3u ildil1g~ SEIIASCE 32-01 De~jgn and Con"lructiol1 of Fro~l ­ Protccted Shallow Foundations EWRIIASCE 33-01 C01l1prehensive Tr'll1sboundary International Wmcr QU:llity Management Agreement EWR I/ASCE 34-01 St;Jmiard Gu idelines for Artificial Rccharge of Gl'otmd Watcr EWRI/ASCE 35-01 Guidelines for Quality A~~ur:mec of in,talled Finc-Pore AenHion Equipment C IIASCE 3()-OI Standard Con~truction Guidelinc~ for MicrolUnnding SE I/ASCE 37-02 Dc~ign Load ~ on Struc\Ures During COll\tlllclion C I/ASCE 38-02 SI:Jntlard Guidellllc for the Collection and Depiction of Exi~tin~ Sub~urf:tcc Utility Oat:. EWRIIASCE 39-03 StunJard Pr:lc til'C fur the Dc\ign and Opcnltion of I-Iail Su ppl"(' ~sion Projcch ASCFJEWRI 40-D:'I Regubllcd Rip,arian Mudd Willer Code ASCEJEWR i 42-04 Standard Practice for the Design and Operation or Precipitation Enhancement Projcct~ ASCE/SEI 43-05 Sci\mic Design Crill'ria for StruClUre~, Sy\tel1l~, and C01111>onenb in Nuclear Fao:lI iticl> ASCFJEW RI +4-05 Standard l>ractiee for the De.,ign .lIld OperatIon uf Supt;::rcooled Fog Di\per\al Projecl\ ASCElEWRJ 45-05 St;mdard Gliidclinc\ for the Dc\ign of Urball Stonnwatcl' Sy~tems ASCElEWR I 46-05 Standard Guideline\ for (he ln~tall;ttion of Urban StonnWiltCr Sy~tems A5CElEWRI47-05 Stnnd.mJ Guiddinc\ for lhe Opcrutilln and M .. inten:mce of Urban Stonnwutcr Sy~tcms ASCEISEI 4!\-05 Dc\ign of Stcel Tr.IO"111i ~~i()n Pole Structures Iii

CONTENTS ~_

... iii

i\C'knowlcdgclllcnts .......... . ...... , ................. .. .......................

~lV

1.0

SCOPE .............. .

1.0

APPLICA BLE DOCUMENTS ...... .

3.0

DEFINITIONS ..... . .......... . ................................... . .... .

1

.to

LOADING. GEOMETRY, AND ANALyS iS .... .. ... . ... .. ........ . . . . . . ..... . . .

3

4. 1

INTRODUCTION ............................... . .....•.................

3

LOADING ....... . . " .. ...................... .. ..... ' . ,., ...... ' •...

3 3 3

4.2

4.2. 1 4.2. 2 4.2.3

Factored Design Louds ....• . •.. .. . . . . .. . . . . . . . . . .. • . . ...•... .. . Lomling Considerations ............ .. . ... ......... . . . . . .. . ........ . Lo ad Ex prc~s io n . ......... . . ... . .... . . .... .. . ... . ........ .

3

GEOMETR IC CONFIGURATIONS. . . . ... . ............................... . 4.3. 1 Configuration Con s ider.Jtioll~ ..... . .. • . . . .. . . .. . . . .•..... . .•..• . ... 4.3.2 Structure Types ................ . ... • .. . ••...•.. . ••.. • .. .•.......

3 3

4.4

METHODS OF ANALYSIS .............................................. . 4.4. 1 Stnlcturnl Analy<;is Methods ..........• . .. .... . . . . . . ..... . . • •..... . 4.4.2 Anal ysi ~ or Connections . .......... .

4 4 4

4.5

ADDITIONAL CONS ID ERATIONS ...... . . . . . . ...... . . . . . . . . . . ... . 4.5. 1 Slructural SuppOrt .... . ................... . .... . .. • . . ..... . ...... 4.5.2 Design Restrictions .................... • • ... • • . . .. • ... . ..•..•.... 4.5.3 C limbing and Maintenance Provisions . .... . .....•. . .•...•. . .• . . . ....

4

5.0

DES IG N OF MEMBERS ........................ .. ..... . ................. .

4

5. 1

INTRODUCTION

4

5.2

MEMBERS ....................... . ..••...• • .. ..• ... • . .. •. ..... . . .• ..... Mat erial ~ ..... . ........................ . .. . . . ..... . ......... . . . 5 .2. 1 5.2. 1.1 Spccilieations .............. . . . . . . . . .. . . . . .... . ......... . 5.2. 1.2 Material Properties. . . . . . . . . • • . . . • . . . . • . . . • .. . ..... 5.2. 1.3 Encrgy+lm pact Prol>C11ies .........•. . .. • . ..••. . •• . . • ...... 'Icn ~ ;on , .... , .... , ................ • .. . . ... .. . ..... . ........... . 5 .2.2 Compression . .... ..... . ............................. ,.. . ..... . 5.2.3 5.2.3. 1 Truss Members .... , . . . . .. . .•....•.. . . . ..•............ . .. 5.2.3.2 Bellm Membc:rs ...... . .• • . . .... . .. . . • .... • ... • . •• . . .•.... 5,2,4 Shear ., .... ,., ..... , . . ... . ......... , ............... . ......... . Bending ............ . ........ , ... . •... . . . ......... , ... ,., .. , .. . 5.2.5 Combined Stresses ...... . . •• . . .. • . . .. • . . . •• . •• . . . •. . .• . . •. . . •. . . 5.2.6

4 4

4 .3

3

4 4 4

4 4 4

5 5 5 5 7

7 7

GUYS ............ ...... .. . . .. . . ....... . . . Material Propcl1ics .......•......... . •.. . 5 .3. 1 Te nsion ...... . ....... .. . , .. . ..•....... . . . .. . . 5.3.2

7

5.4

TEST VER IFiCATION ., .... , ..... , .... , .... , ... ,................ .......

8

6.0

DESIGN OF CONNECTIDNS ....

8

6. 1

INTRODUCTION .... ,. . .... , ..... .• . • , . • . . •... , .. . . ....•. . . • . .•. . . . ...

8

5 .3

7

7

6.2

6.3

8 8 8

6.2.3

Bolts Subject to Tension ........................• . . ..•..•. .. .•....

6.2 .4

Bo ilS Subject 10 Cumbined Shear and

. . . . . . . . . . . . . . . . . . . . . . . ..

9

6.2.5

Bearing Stress in Bolted Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

9

6.2.6 6.2. 7 6.2.8

Minimum Edge Distance .. and Bolt Spacing for Bolted Connections.. .. ... Bearing Stress in Pinned Connections ............................... Minimum Edge Di stances fo r Pinned Conn ec ti on ~ .....................

9 9 9

WELDED CONNECTIONS ........ . .... . ......................•.......... 6.3. 1 Material Propcni cs ................... • .. . ... •• .......•.......... 6.3.2 ElTccti ve Area . . ....... . ..... . ..... . .• . . . •..• . .. .•..• . . . .. ...... 6.3. 3 Design Stresses . . . . .................. . ...... .. ....... . .......... 6 .3.3. 1 Through·Thiekness Stress ....................... . . . ....... 6.3.4 C ircumferential We lded Splices ..................... . . . ............ 6.3.5 Flange anti BiI ~ PI;lte to Po le Shaft Welds. . . . . . . . • . . . . • . . . . . . • . . . . . .. 6 .~.6 T·Joints ................................ . .........•. .. .........

III 10 10

Te n ~ ion

8

11

12 12 12 12

6.4

FIELD CONNECTIONS OF MEMBERS ..............•.......•........•.. 12 6.4. 1 S lip Joints .. .. . ......................•......•....... . ....•.. 12 6.4 .2 Base and Flange Plate Connections ...... . ..........•..•. . . ..•..•.. . 12

6.5

T EST VERIFi CATION .........................•.....•.... . .•.. . .........

12

7.0

DETA ILI NG AND FABR ICATION ............................ . ..... . ......

12

7. 1

DETA ILING .............. . ............................................. 7. 1. 1 Dnlwings ...................................................... 7 1.2 Drawing Rev iew . . . . . . . . . . • . . . . . . • . . . . . . . . . • . . • . . . . • . . . . . .. 7. 1.3 Erection Drawings. . . . . . . . . . . • . . • . . . . . . • . . . • . . . . . . . . . . . . . . . . . • . . . 7 1.4 S hop Octail Drawings ............. . ....•............ . ............ 7. 1.4. 1 Material ....................................•........... 7. 1.4.2 Dimcn'iions and Tulerances ..................... . .......... 7. 1.4.3 We lding .................................... . .. . .. 7. 1.4.4 Corrosion and Fini sh Considcratioll 'i .. . . . . . . . . . . . . . . . . . . . • . .. 7. 1.4.5 Other Rcquirement:. ........................... .. .•...•. ..

12 12 12

7.2

"

BOLTED A ND PIN NED CONNECTIONS .......•.. . . . ••... •.. .....• .. ...... 6.2. 1 Malcrials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.2 Shear Stress in BC:lring Connections .......................• . .......

FABR iCATION..... . ................................................... 7.2. 1 Material ....................................•.............•.... 7.2.2 M:lterial Prepanuiull ......•. . ...• .. .•..•...•........ . ....•...•... 7.2.2. 1 Culling.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7.2.2.2 Forming ...................................... . . ....... 7.2.2.3 Holes .. . .........•.... . ........................ . ....... 7.2.2.4 Identification .................................•.......... 7.2.3 \Vclding ......................•................................

13 IJ 13 IJ

13 13 13 13 13

13 13

13 14 14 14

8.0

TESTING •......................•...................................... 14

8. 1

INTRODUCTION . . . •• .••.••.••...•••..••.• • .••. . ••..•..•... • ...........

14

8.2

FOUNDATIONS ..... ... •.• ... ..•. . .•..•..• . .••.••..••••••..•• . .••......

14

8.3

MATER IAL . . .. .. ... .. .... ... .. . .. . .. . .. ... .. ..... .. .. .. .. . • .. . . .. .. .. . 14

8.4

FABRICATION ....... .

. . . . . . . . . . . . . . . . . . . . • . . . . . . • . . . . . . . • . . . . . . . . . ..

14

8.5

STRA IN MEASUREMENTS ......•..•..••.•...••••....•.••..••. . ••.......

I~

8.6

ASSEMBLY AND ERECTION ................................•.......•.... 14

8.7

TEST LOADS ..

14

8.8

LOAD APPL ICATI ON .................. .. . ......•.......................

14

8.9

LOAD ING PROCEDU RE. . . . . . . . . . •. . . . •• . . . . • . . . .. . • . . . . . • . • . . • . . . . . . . ..

14

8. 10 LOAD MEASUREMENT ............................... .

. .........

14

R. I I DEFLECTIONS .. . ...... .. .....................•....................... 15 8. 12 FA ILU RES ......

.. ....................................... . ....

15

8. 13 POSTTEST INSPECTI ON ................................................ 15 8. 14 DI SPOS ITION OF PROTOTy PE ........................................... 15 &. 15 REPORT ............... ...

........................................

15

9.0

STRUCT URAL MEMB ERS AN D CONNECTIONS USED IN FOUN DATI ONS...

15

9.1

INTRODucn ON .... .

15

9.1

GENERA L CONS IDERAT IONS . .

15

9.3

ANCHOR BOLTS. .................... . . .....•.. . .....•. . ...... . . .•..... 9.3.1 Bolls Subjccl lOTcnsion ...............•....................•.... . 9.3.2 Shear Strc~s ......................... ............ ............ 9.3.3 Combined Shear and Tension....... .... ......... .. . .... . .......... 9.3.4 Development Length ... . .........••........ • .. . ....... . .... .. ....

15 15 16 16 16

9.4

DIRECT-EMBEDDED POLES ....

17

9.5

EMBEDDED CAS INGS ... .

9.6

TEST VER IFICATION ................................................... 17

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

......... 17

10.U

QUA LITY ASSURANCE/QUALIT Y CONTROL .......................... .

17

10. 1

INTRODUCTION ................................................. • ..

17

In2

QUA LIT Y ASSURANCE ............................................ . 10.1. 1 Design lind Drawi ngs . .... . . .... . .. ... ............ .... ....... . 10.2.2 Mntcrials ................. . .... . ......... . ..... . . . ..... .. .. ... . 10.2.3 Weldi 11g... . ....................... . ...................... . 10.2.4 Nondcstructive Testing ....... .... .. . .... ............ . . . ..•..• . . . . 10.2.5 Tolcrances ................•.................................... 10.1.6 Su rf;I(':e Coatings.. . . . . .... . . . ....... ... . . .............. . 10.2.7 Shil)ping .............•........................................

17 17 17 17 17 17 17 18

10.3

QUA LITY CONTROL .......................... ....... .................. . 10.3. 1 Matcrials ..................................................... . 10.3.2 Vi<;ual lnspcclion .......................•........................ 10.3 ..' Dimcn!>ional lnspcction ..................•...•...••....•..•....... 10.3.4 Surface Coati ng Inspe(.·lion ...............•............ .. ..... . ... . 10.3.5 Weld In ~pcc l ion . ............................................ . 10.3.6 ShipmcllI and StoraJ;lc .............. . .. . . . . .•................

18 18 18 18 18 18 18

11.0

ASSEMBLY AND ERECTION ............................ . ....... . .. . .. .

18

11.1

INTRODUCTION ....... .

18

t 1.2

II AN DLI NG ............................ . ............•...........•...... 18

11.3

SING L E POLE STRUCT URES t 1.3. 1 Slip Joi ms .............................................. .

19

I.

'"

11 .3.2 11 .3.3 11 .3 ,4 11.4

Boiled Flange Joint ~ ....................... . .•...•............... Allachll1cnts to Pole Seetion ~ . .................................... Erection of Assembled Structures .... . . . . . . . . . . . . . . . . . . . . . . ..

FRAME TYPE STRUCTURES . ........ . .... . . ....•.......• ..... . 11.4. 1 Slip J()int ~ in Frames .. . ....................... . . . . . .. .. . . .•...... 11.4.2 Erection ...... . . .........••.•.••...••.••.•. • •.• •. ..••..... 11 .4,3 Bohed Fmme Connections ........................................

19 19 19 19

I. 19 19

11.5

INSTALLATION ON FOUNDATION ....................................... 19 11 .5.1 Anchor Boli and Base Plate In ~tallalion .. . . ..•.••...••..•..... 19 11 .5.2 Direct-Embedded Poles ............... . . . ..•....•................. 19

11.6

GUyiNG ............................................•................. 19 11.6.1 Guy Anchor Location .............. . .... . ................. 19 11.6.2 Guy Installation . . . . . . . . . . . . . •. . . . . . . . . . . . .• • . . . . . . . . . . . • . 20

11.7

POSTERECTION PROCEDURES ........................................ [1 .7. 1 Inspection ............................•.................... . .... 11.7.2 Grounding ................................................ . .... 11 .7.3 Coating Repair ..............•.. . .... . .... . .....•. . . .. ..•... . .... 11 .7A Unloaded Arms ........... . .... . ..•...... . ..•.......•.... . ...... 11 .7.5 11'lf(lwarc Im>lal13tion ............................................

20 20 20

20 20

20

COJ1lmcntnry C4.0 LOADING . GEOMETRY. AND ANALyS iS ...... .. ... .. ... . ..... . . . ..... . . . . 21

C4.2 LOADING ............................... ....... .................... . .. C4.2.1 Factored Design Loads .......................................... . Louding C(lIl~ider.lt l ons .... . .................... •.......•.... ... C-'.2.2 C4.2.3 Load Expression ............... ....•...•• .. •• ...• .. . •. . .•.......

21 21 21 21

C4.3 GEOMETRIC CONFIGURATIONS......... . ............................. 22 C4.3. 1 Configur.llion ConsidcnuiOIl'i ......... . .... ... ..................... 22 C4.3.2 Stru cture Types ................ .. ..• .. ...•.. . ••.• .. .. . •.•... .... 22 C4.4 METHODS OF ANALYSIS .................... ...... ..................... 22 C4.4. 1 Structur:ll An:lly"is Methods ............................ .. .. . 22 C4.5 ADDITIONAL CONS IDERATIONS ....... . . . .. . ... .. . . . .. .... . . . ... . . .... . C4.5.1 Slructur:ll Support ....................... .•.. .. . . . •.... . .... . .... C4.5.2 Dc~ig n Restrictions .............................................. C4.S.3 Climbing and MaintclHln('c Pro Yi~ion~ ...............................

23 23 23 24

C5.0 DESIGN OF MEMBERS . . ................................................ 24 C5.1 INTRODUCTION ....................................................... 24

CS.2 MEMBERS ....... . . .... ...... . ............. . • ....•.. ..•.......•........ C.'U.l Mutcrials CS.2. 1.1 Specilicmions . . . . . . . . . . • . ...•.......... C5.2. 1.2 Matcri:!1 Pl'Opcrti~ . . . . . . . . . . . . . . . . • . . . . . . . . . . . . • . . . . . . .. C5.2.1.3 Energy-Impact Propcrh c~ ...............•................ Tc n ~ion .... . . ..... . . ............................... . ......... . . C5.2.2 Compression .........................•••.•.••.••....•...•...... C5.2.3 C5.2.3.1 Truss Mcmber<> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. CS.2.3.2 Bcam Mcmber, ........................................ ShCill' ..................... .. .. . ......•.....•...•..••. .. ....... C5.2.4 C5.2.5 Bending ...................................•................... viiI

24

2' 24 24 24 25 25 25 25

29

2.

CS.2.6

Combi ned Stresses. . . . . • . . . . . . . . . . . •. . . . .. . . .. . . . . . . . . • . . . . . . . . .. 29

C5.3 GUyS........................... . ..................................... 29 CS.3. 1 Material Propcnics ..........•.................................. 29 CS.3.2 Te nsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ................. 29 C6.0 DES IGN OF CONNECTIONS ............................................. 30 C6. 1 INTRODucn ON ....................................................... 30 C6.2 BOLTED AND PINNED CONNECTIONS ........................ ......... Mutcri
30 30 30 30 30 31 31

C6.3 WELDED CONNECTIONS ..............................••. • ,. . .......... 3 1 C6.3.3 Dc"ign Stresses ............................................... 31 C6.3.3. 1 111roug h -Thick nes~ Slre~s .......... , ..................... J I C6,4 FIELD CONNECTIONS OF MEMBERS .......... . .. . . . .. . .................. 3 1 C6.4. 1 Slip Joint s ....................... . . . . • . . . •• . • • . . . . . . 31 C6.4.2 Basc and Flangc Platc Connections ......... .................. 32 C6.5 TEST VERIFI CATION

....................... 32

32

REFERENCE ............. . C7.0 DETA ILING AN D FABRICATION C7. 1 DETA ILING ........................................ . .............. C7. 1.1 DrJwmgs ..................................................... C7. 1.2 DI'awi ng Review .................•. . ..•....•....•...••.•.•...... C7. 1.3 En."(lion Drawi ngs ....................................•...•...... C7.!A Shop Detai l Drawings ............................................ C7. 1.4.2 Dimensions illld Tolerances. . . . . . . . . . . . . . . . . . . . . . . . . . . C7. 1AA Corrosion lind Fini sh Considcfilli olls . . . . . . . . . . . . . . . . . • . C7. IA.S Ol ilcrRequircmcnls ..................... . . . ......... C7.2 FA BRiCATI ON ................................ . ............ •.... ....... C7.2. 1 Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C7.2.2 Material Prcpar.l tion ...............•.........•....•.............. C7.2.2. 1 Cutting ........•••..•••.........•...••......••..... C7.2.2.2 Form ing .........•.................................... C7.2.2.3 Holes ................................................ C7.2.2.4 Identilie3tion ............•.. . .. . . . ............•........ C7.2.3 Weld ing ............... . ..... .. . . .. . ...... . .... . ..... . .....

CS.! INTRODUCTION CS.2 FOUNDATI ONS ~1 ATE RI AL

32 32 32 32 .13 33

33 33 J3 33 33 3-1

34

M

......................... 34

C8.0 T ESTING

CS.3

32 32

................................................ M ........ . .. . . . ... . . . . . . . M

.............................................. . . ..... .... 35

C8.4 FA BRICATI ON .............................•........................... 35 CS.S STRAIN MEASU REM ENTS ................ . ............................. 35

"

C8.6 ASSEMBLY AN D ERECTION ......••.. . ...•....•.............•. . ..•. . .... 35 eS.7 TEST LOADS ........ ... ....... . , . .. . ...••. . . .. . . . . ....•....•..••...... 35 eH.8 LOAD APPLICATION ................................................... 35

C8.9 LOADING PROCEDURE . . . . .. . . .. . .. . . . . . . . . .. .. . . . . . . .. . . . . . .. .. . . . . . .. 35 C8. IO LOAD MEA SUREMENT ...... . .

. ....... . ...... .. ........... .. .... 36

CtU I DEFLECTIONS ................. ..

36

C8. 12 FA ILURES ...................................... .

36

CH I3 POs'nEST INS PECTION ....... ...... ......•.... C8. 14 DISPOS ITION OF PROTOTyPE ......... . CS. 15 REPORT ........ ..

. .•.................. 36 . ................... 36 . ........... 36

C9.0

STRUcrURAL MEMBERS AND CONNECrJONS USED IN FOUNDATIONS ..... 37

C9. 1

rNTRODUCfION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C9.2

GENERAL CONS IDERATIONS

C9.3

ANC I-IOR BOLTS .....................•............ . .................... C9.3. 1 Boll!; SubjC{;t to Tension .......................................... C9.3.2 Shear Stress. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. C9.:\.3 Combincd Shear and Tension ...... . . .... . . •. ... . .. ..••••.. . ••.. ... C9.3A Devclopment Length .................•...............•.. . ........

37

... . .... . .. . ... .. . • 38 38 38

38 39

C9.4

DIRECT· EM BEDDED POLES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 39

C9.5

EMBEDD ED CAS iNGS ........ .

39

C IO.O QUALITY ASSURANCE/QUA LITY CONTROL ...

39

CIO. I INTRODUcrlON ....................................................... 39 C IO.2 QUALITY ASSURANCE ................. .... .......................... .. C I0.2. 1 Design and Dmwings .......•..... . ................••. . ........... C 10.2.4 Nondestructive Tc\;ting ......... . .... . .... . ...... . .... . .... . ...... C IO.2.5 To1cr;l IlCCS ..................................................... C 10.2.6 Surface Coul ings .... ......................... C I0.2.7 Shippi ng........................ . ... . .................... .. .

31)

C 10.3 QUALITY CONTROL ..................................... .. ...... ... . C 10.3. I M:lIeri:lls............. . . . . . . . . . . . . . • . . . . . . • . . . . . . . . . . . . . . . . . .. C I0.3.3 Dilllensionall nspcction ........................................... C 10.3.4 Surfuce C(luling InSI)L'Ction ........................................ CI0.3.5 Weld I I\~pcction ................. . . . .. . .... . .... ... .............. C 10.3.6 Shipment and Stor:'lgc .. ..... ........•....•....••..•••...•........

4()

40 40

40 411 40

.to 40 40

.to 41

C II.O ASSEMBLY AND ERECTION ............................................. .tl C II . I INTRODUCTION ......................... . ...........•................. 41 C 11 .2 HANDLI NG ................ . C ll.3 SING LE C II.3. 1 C 11.3.2 C 11.3.3 C 11.3.4

. ... •. . . . .... . • ...••.............. •.... .. 4 1

POLESTRUcrURES ............................................ Slip lu1nts ..................................................... Bolted Flange Joint s ... ..... .. .. .. .... . . .... .. ................... AUachrncllI S 10 Pol e Sections ....... . ...•.... . •• . . ..•......•....... Ercclion ~ or Asscmbled Slrucll1 re~ ........•....•....•...............

.tl 42 42 41 42

CI1.4 FRAME TYPE STRUCTURES . ........... ...................... ... C 11,4. 1 SlipJoint5inFrame~ . ............................ ....... C IIA.2 Erection ............. ..............................

42 43 43

CII .S INSTALLATION ON FOUNDATION ...............•.....•................ 43 CIl.S.1 Anchor Boll (lnd Base Plate Installation .................. . ..•..... 43 C II.S.2 Direct-Embedded " oles ........................................... 43 C II .6 GUyiNG ................ . C I I.6.1 Guy Anc.:hur Lo<;ation C 11.6.2 Guy ' n~l(llli.llion . CIU

. ..........•.................... 43

43 . ........ . . ....... .. . ........ .. .. 44

POSTEREcnON PROCEDURES ..... C 11,7.1 C II .7.2

C I I.7.3 C I1.7.4

C I I.7.S APPENDIX I

. .. . .. .. . .. . . .. . . . . . .. . .. . . . . . .. 44 Inspcc.:tion ............................. . ......... ... ........... 44 Grounding ................ . ...... . .•......... . .... . .......... 44 Coming Repnir ......... . .••. •.••••.• . •• ..•••.••.•.••..•••...... .J.4 Unloaded Arms... ..... .. .................................. 44 Hardwarc Installation ............................................ 44

NOTATION. .. .. . ... ... ....................................... 4S

APPENDIX II PROPERTIES OF VARIOUS TUBULAR SECTIONS ............ •. ..... 46 APPENDIX '" 1I0RIZONTAL TESTING ...................................

4~

Tcst Equipment ............................ ..•... . . Test Ilruccdurc for Pole Te~t .... . ........••.•. . •.• .• •.• •. •.. •.

48 48

APPEND IX IV HEADED ANCHOR BOLTS ....................................... 48 "leaded Bolls Development Length. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48 Background .......................... ••... •.... •. .......•....... 48

APPENDI X V ASSEM BLY AND ERECnON ............................ .. ....... 49 Intnxluctlon .. .... ........ ........ ....... .... .................... 49

Helicoptcr' Erection ............................................... 49 In-Service Structure MuirUcn:tllec nlld I Il~pe(:tjon ....................... 49 Wind-Induced Vibration ............................. . . . ...••...... 49

APPENDIX VI SHAFT-TO-FOUNDATION CONNECfION .......................... SO Base Plmes An
INDEX ................... .. ................................................. S3

"

FOREWORD The Engineering Manual arllt Rcporl on Engineering Practice No. 72 titled " Dc~ig n of Steel Transmission Polc Stnlcturcs" has been used by electric tron~mis­ ~ i u n dcsign prorc~s i{)nal \ since 1973. The purpose of the design guide was 10 pl'uviJe a UnirOml basi~ for

the tlc~ign. fabricnlio n. testing. assembling, and crecllog of slce l lransm;'\sion pole structures. Because many changes cominuc 10 lUke place in the steel pole IIldUSlry. in 1989 it Wll'i pwposcd lhal ASCE form a comminec to develop:1 , '''ndard. 111C proposli was approved. ;lnd the committee was organized in 199 1. The second edition of Manual 72 served as the primary resource document for the development o f thi .. ~1;lIldard . The previous worl.. of the ASCE task COIl1m;ltcc on M;lI1ual 72 is greatl y apprc<:iatcd. This standard includc,! commentary and append ices th:1I arc furni shed as supplemental information. The commentary :md appendkcs :lfe 1/(1/ lll:lnd:llOry.

Thi<; standard has been prepared in accordance wl lh recognil.ed engincering prin<:iplc<; and should nOl be mcd withoul the use r·~ compelent I..nowlcdgc for a given application. The publication of Ihi s standnrd by ASCE is not intended :IS ;1 warrant that the infurmatiun contained therein is suitable for any ge neral or spcdfil.: Ul>e, and the Society takes no posit ion with rega rds to the va lidity of patent righls. Users arc advised Ih:ll the determinatio n of patent rights or rhk of infringement il> entirely their own respon~ibility. 11 is with much appreciation that we acl..nowledgc thc contributions o f two l'ommittcc members who :Ire no longer with us, Jerome G. H;lIlson and Dan S. Thiemann .

ACKNOWLEDGEMENTS This

~tandal'd

was prepared through the t;onscn'iUS pn::w.::cs.; by balloting in compliance with proccdurc~ of ASCE"s Codes and Standards Activit ies standard ~

Richard F. Aichinger. P.E. Gary E. Bowles. P.E. David G. Brinker

Michael D. Brown. P,E. Donald D. Cannon

Jerry G. Crnwford. P.E.

Dana R. Cri~y, P.E. Martin L. Dc La Rosa, P,E. David Endorf. P.E. Michael R. Gall. P.E. Lewis II. Grant, P.E. Bobhy G. 113glcr, P.E. MOIgdi F. hhac, Ph.D .. r .Eng. Brian L:lcoun;icrc. P.Eng. Ouo J. Lynch. P.E. Leon Kempner. Jr.. Ph.D .• P.E. Mll,solld Khuv:lri. P.E. Fred II . Kulhawy, Ph.D., P.E .• G.E.

COlllmiIlCC. Those individuals who serve on the Design o f Steel Tr:Ul~JJli"sion Pole Structure,> $tand:mis Commiucc arc

r,lUl M. Legrand, P.E. William L. Magee. P. E .. Vicc-Chmr TCITY C. McAn n:llly. P.E. Marlo A. Menlovc. P.E. George E. MurrJY. P.E. William B. Mills. P.E. Robert E. Nickerson, P.E, Secretary Garold D. Oberlender. Ph.D .. P.E. Robcl1 L. Patterson. P.E. Alain H. Pcyrol. Ph.D.. P.E. Ronald E. Randle. P.E .. Chait Randall L. Samson. P.E. Pedram Sadr. P.E. Majcd J. Saleh Kenneth L. Sharpless. P.E. Jerry Tang. P.E.

Marton W. Vogl. P.E.

Design of Steel Transmission Pole Structures 1.0 SCOPE Dc~;gn of Steel Transmission Pole Structures spccilics requirements for the design, fabrication, testing, assembly. and erection of cold-fonneu tubu lar melllbers und conneclions for sleel elcclric<Jltr;msmission

1)OIe structures. Structure componcnl s (members, conncctjon~, guys) arc selected to resist fuclored design loads at stresses approaching yielding. buckling,

fr;n.:tun,', or any Olher l imiting condition spcdficd in Ihis st;mdurd . Distribution. substation. communil'tllion.

unct railroad electric traction structures arc nOI included within the scor~c of this standard . Units o f measurement herein arc express-cd ii rst in English units followed by Ihe IntCl'Ilulional System (51) units in p:lfcnthcse". FOOllll iac are based on English unit~. and, thus. some fonnulae require a conver~ion factor to usc 51 units. The appropriate conversion f:lelOr is given following each formula.

2.() APPLICABLE DOCUMENTS The following d(H;umcnt:

standard~

are referenced in this

ASTM International (ASTM) St:ll ldards A6IA6M-04 Standard Specilication for Gencml Requirements for Rolled Structunll Sleel Burs. PI:IICS. Stwpes, and Sheet Piling A36/A36M-03a Standard Spccificntion for Carbon Structuml Steel A I23/A I23M-02 Stand:lrd Specilkation for Zinc (l'lol-Dip Gulvanized) Coatings on iron and Sleel Prlxlucts A 143/A 143M-OJ Standard Practice for SafegU:lrding Against Embrittlemcnt of Hot-Dip Gatv.mizcd Structllr:ll Steel Products nnd Procedure ror Detecting Embrittlerncnl A I53/AI53M-03 Standard Specification for Zinc Coating (tlot-Dip) on Iron and Steel Hardw.trc A I93fA 193M-03 Standard Specification for Alloy-Steel and Stainless Steel B()hing Mmcrials for lligh-Tetllpcraturc Service A307-OJ Standard Specification ror Carbon Steel Bolts and Studs, 60,000 psi Tensile Strength A32S-04 Standard Specific'llion rur St ructural Bolls, Sted, Ileal Treated, 1201105 ksi Minimum Tensilc Strength

A325M-04 St:ml!:Iro Specilic:uion for Structural Bolts. Steel Heat Treated 830 MPa Min imum Tensile Strength (MetricJ A354-03a Standard Specification for Quendtcd and Tempered Alloy Steel Boits, Slud~, and Other Extemnlly Threaded Fasteners A370-03a Stand:lrd Test Methods and Delinilions for Mechanical Testing of Steel Products A385-OJ Standard Practice for Providing I-lighQuality Zinc Coat ings (Hot-Dip) A394-00 Standm·d Specification for Sleel Trnll srnis~ion Tower Bolts, Zinc-Coated nnd Bare A449-04 Standard Specification for Quenched and Tempered Stee] Bolts and Studs A47S-03 Standard Specification for Z inc-Coaled Steel Wi re Strand A490-04 Standard Spccific3tioll for Structural Bolts. Alloy Steel. Hcat Treatcd, 150 ksi Minimum Tensile Strength A490M-04 Stand;}I"{] Specification for HighStrength Steel Bolis, Classes 10.9 nnd lO.9.3. for Structural Steel Joints [Metric1 AS29/AS29M-03 Standard Specification for l1igh Strength CCcifi~'ation for I-lighStrength Low-Alloy Structuml Sleel with SO ksi [345 MPal Minimum Yield Point to -l in. [100 mill I Thick A595-98(2002) Stalldard Specification for Steel Tube". Low-Carbon. Tapered fl)r Structural Usc A606-01 St:ll1d:lrd Specification fOf Sleel. Sheet and Strip, High-St rength, Low·Alloy. Hot-Rolled, and Colli-Roiled, wilh Imprm'ed Atmospheric Corrosion Resistance A6IS/A6ISM-04 Standard Specilic
DESIGN OF STEEL TRANSMISSION POLE STRUCTURES

A673/A673M-02 Standard Specificat ion for Sampling Proccdurc for Impact Testing of Structural Steel A780-0 1 Stand
3.11 DEFINITIONS

Aeolian Vibration- High-frequency. low itlnplitude vibration gencrated by :I low velocity stcady wind blowing "cross the conductor or struclUral member. Hlast Cleanjng-Clc:ming ure.

2

C:unb4.'r (or Pr('eamher)--Polc curv;Jture, induced in ftlbrication. used to counteract predetermined polc ddlection. such that thc pole will appear str:light under a specified IO:ld condition. Circumferential Wcld-A weld joint directionally perpendicu lar 10 thc long axis of a structunll member. Commonly used to join two closcd-section shapes of a COlllillon diameler. Complete Fusion-Fusion thai has occurred ovcr the e ntire base melul i>urf:H;e intended for welding :lIld betwecn all adjoining weld bcads. COIllI)lctc Juint PCllctration-A penctration by weld metal for the fullthickncss of the base metnl in a joint with :1 groove weld. O('sign Str{'ss- The nl1lximum pcrrnittcd stre"s in a given member. Direct-Embedded I")oil.- -A structure in which the lower scction is extended below grou ndline a predetermined distance. Edge DislllllCL'--The distance between the centcr of a connection hole
ASCF.1SEI ·Hi·OS

column ~ec li on or Ihe compressive ~ ide of a bea m ,eclion because o f the inability of Ihe section to rcsj,1 the comprcs~ivc ~ I rcss in Its current geomctric shnpe. Loosely Uolted- Bulted cunnections in which the nllt ~ arc dmwn into contact wllh the mati ng "ur+ face without being tightcned beyond Ihat which call be obtained wi thout the usc of tool~. 0 \\ ncr- The owner o f the proposed Iran5mi,· ~ I{ln line or the owner·" de:. i g n ~lIcd reprc,entatl ... e, who may he a cOI1",lIlIing engineer, general contractor. fir other. Ra ke- The amount of horil.Ol1Ial pole top displul:cmcnt l'reated by installing a pole tilted out of plumb. 11 i" used to counteract prcdelCrmined pole deflection such that the potc wil l appear plumb under a "pcci fi ed load condition. Secu rity Load-A design load used to decrease thc ri~l of a cascading type line failure. Load:. thill could cau~ cascading could be we:Uher-relah.'cred tubular pole \cclion,. S nllg+Tight- Tighlne:.s obtilined manually through the full efTorl of a worker using an ordinary spud wre nch or as obtilinec1through u few impacts of an impact wrench. SUlbility- The :lbilily of:t MruCture or member hJ wpport a gi ... cn load without e.~periencing :l sudden change in configuration. St ruct ure Drsigncr- Thc party responsible for thc design of Ihc Mructurc. M:ty be an agcnt of the owner or fabricato r. T-J oin t -A Joi nt hctwecn two mcmbc .... located np proxill1:ltely at right ang les 10 each other in the form of a "r·. Test Engineer-The peNon as~ignell o\'enlll rc!>ponsibility for il 'itrul'lure test. T hrough-Thicknt.'SS Strl'Ss-Tensile stTCsses through the thiclness of the plate IhatCiln cause f"il+ ure paral1c1to the plate o r lube .;unnce. Trus.'i Membe r-Member designed to carry only ol}!,ial force.

4.11 I.OA DI NG. GEOM ET RY, AND ANALYS IS . tI INTRODUCTI ON

Thi !> section details the minimum basil' informatIOn thm thc Owner sha ll pmvide in a wri ue n '1pecifieation to enable the Siructure Dc<;igncr to de~ i gn the ~ true­ ture. This sect io n :llso detail~ the 1I\Clhods of analysis Ihat \/utll be utilized by the Structure Designer to design the structure.

4.2 LOADING 4.2.1 Faelored Dc.<;ign Luads Factored design loads shall be determined by the Owner and included in the d('~igl1 !tpccifieation. dmw+ ings. or documents.

. 1.2 .. 2 Loading Consid erutions 111e development of fac tored design loads shall consider the following: I . Conductor and shicld wire properties,

2. Minimum legislated loads, 3. 1·l i~l(lri ~·a l clim:.nic condiliun::., 4 . Structure orientation, 5. Con<;truction and maintenance oper.lIions, 6. Line security pro\'isit)n~. and 7. Unique lu:tding \ ilUatiuII!>. 4.2.3 Load Exp ression Factored design loads !>hall be 'IJCl' i(ied by till' Owner and shall be expressed in the form or load trccs or 111 tabular form. Factored design IQads shall include the magnilOdc. di rect ion. and point of' "pplication wilh fC\pec l \() a sing le orthogonal coonlinate 'ySlern.

4.3 GEOMETRI C CONFI GU RATIONS 4.3.1 Cunligura tion CCln, idc r:ltiOlls Tubu lnr :.Ieel pole Struclures sha ll be designed with geoillctrie eonJi gunllion, Ihat arc based un electric
DESIGN OF STEEL TRANSM ISS ION POLE STRUCTURES

-I... I\'IETHODS OF ANALYS IS

5.2. 1 Mlltcrials

The Strut·turc Designcr shall usc established principles of ~lrucHm.l1 analysis to determine the forces ond momcnts caused by the fuctorcd design louds.

5.2. 1. 1 Specijicaliolls

4.4.1 Siruetnnil Analysis Methods The Structure De~igncr shall ut ilize geomctrically nonlmc<Jr clastic ~t re::.s analysis methods.

ASTM A36!A36M, Standard Specification for Carbon Structural Steel; ASTM A529/AS29M. St:mdard Sp...."'Cification for High·Strength Carbon-Mang;lnesc Steel or Structural Quality: ASTM AS72/AS72M. Standard Spcl.:ilication for High·Strenglh Low·Alloy Columbiu m-Vanadium Structuml Stccl: ASTM A581:UA588M, SlU nd:lHI Speci fi cation I'or Hi gh·Slrcnglh Low·Alloy Struct ural Steel with 50 ksi (345 MPa) Minimum Yield Point to 4 in. (IOn mm) Thick: ASTM A595. St:llldlird SpecHkation for Steel Tubes, Low·Carbon, Tapered for Structuml Usc: ASTM A606. Standard Specification for Stecl. Sheet :Uld Strip. High·Strength, Low·Alloy, Hot· Rolled. and Cold· Rolled. with Improved Atmosphcric Corrosion Resistancc: ASTM A633/A633M, Standard Specific:ltlon for Normalil.ed Iligh·Strength Low·Al loy StNJctural Sted Plates: ASTM A87 1/A'I!.7 1M, S1:.Ind:ml Specification for High·Strenglh Low·AII(lY Structural Steet Plate with At mospheric COITosion Resistance: and ASTM AIO I IIAIOI 1M, Standard Spccilicmion for Steel, Sheet and Strip. lIot·Rolled. C:... bon. St ructu raL High·Strength Low-Alloy, and High· Strength Low·Alloy with Impf( )\'cd Formability.

4 .... 2 Analysis of Connections The Structure Designer shall be responsible for the analysis of all connections. This onolysis sholl be \ubstantiated by s\rc~s c;lk:ulatloll~ or by test results.

4.5 ADDITIONAL CONS IDERATIONS 4.5. 1 St rucluml SUPIKlrl Thc Owner .. hall specify the type and dcgree of supPOr1 provided by foundalion~ or guys that will be utilized with the I1lsl:LlIed ~true t ure. Additional require. menh regarding fou n dat i on~ appcur in Section 9.2. 4.5.2 Design Rcstriclions The Owner sh
5.0 DESIGN OF I\1EMIUmS

Materials conforming to the rollowing ASTM Specifications arc suiwble for usc under thi s sllmdard :

This listing of suitable stcels doc" 1I0t exclude the use of other steels thm con form to the chcmical nnd II1c(.'hanical propcl1ies of on(.' or the listcd .'> l>ccilica· tions or other published ~pccilica t i(lll~. which ('stabh~h thc propertics and suitabil ity of the lI1atenals. A" a mi nimum, matcrial ~hall mcct thc requirements of ASTM A6 or ASTM A568, as upplicable.

5.1 INTROD UCTION 5.1. 1.2 Mated,,/

Thc dc"ign SlrCS~cs ror members shull be based on ultimatc strength methods using factorcd design loads.

5.2 MEMBERS 11lis '-CClion contains criteri:1 for dctennining dc~ign stress Ic"ds in tubular members and III truss members. Ground lllecves shall nOI be considcrcd as structurnl lIlembcl"
"

Pmpertil!.~

The yield strcs~. I"" and the tensile stres". "'", shall be the spe(.'ilied minimum values determined :Iccording to Ihe .. ppropri:lle ASTM spcci l'ic:llion. The modulus of clust icity. E. for , tec! is defincd \(J be 29,000 k~i (200 GPa). 5.2. 1.3 Elfergy·lmpacl Pmperlie.~

Impacl properties in the longitudin
ASCEISEI 48·05

described in ASTM A370 and. at a minimum. shall meet thc re(luircmcllts or 15 rt-Ib (20 J) absorbed energy at a tempCnLlUrc of -20°F (-29°C). Absorbed energy rt'quil'Cmcnts for subsizc test specimens shall be in
The tcnsile "t ress shall not c:o;cecd either of the following: where F, '" ,.~

0'

S F,

:

compressive stres~ perm illed; specificd minimum yield stress; modulus of ela~licity; unbmced length: , = governing radius of gyration: and K efTective length fa(:lOr.

F• F, E L

~

KLj,. is the largest slenderncss rutio of an)' unbruccd

5.2.2 Tension

p A.:5 f, ,

where

.... here

,.~

= O.83F.

(&1. 5.2-2)

~gmcnL

Truss members made of ungles shall be designed in accordance with Section 3.7 of ASCE 10 (503).

5.2.3.2 IJC(UII Members The limiting va lue~ of w/Ilmd D,,/I spcci lied in this sect ion may be exceeded without requiring a reduction in extreme fiber strcs~ if local buclling stability is dcmotl<.trated by an adequate program of test,.

• 5.2.3.2. J RI!8Ulu,. Polygollal /lkmlJer.f For formed,

where P,

I', F.

P

A, A.

~

~

regular polygonaltubul:Jr member". Ihe comprcs... ive stress, P/A + Me/I, on Ihe ext rc me Jiber shAll nOI exceed the following: OctugonaJ. hexagonal. or rectangular members (bend angle ~ 45°)

ICIl . . iic ~trcs~ r>crm il1cd; specified minimum yield stress; specified minimum tensile ~tress: axial tell"ion force on mcmber: gro ...s cross-section;:!l Olre:J; and net cross-sectional area.

.

F - F,

5.2.3 Compression Membcl'l> ,ubJected to compressivc forces <;h:lll be checked for general stnbihty and loe:11 boclling. TIle compres!oivc !>IreSM!~ ~hall not cxc(.'Cd those pcrmined in Ihe following sections.

F~ =

1vF,

1.42F, ( l,(l - O'<X)l14 jl1

when

5.2.3.1 Trim' McmbenFor tnlss mcmbers with a uniform dosed cross section, the actual compressive <;Ircss./., shall not exceed the compres~ive stress perrnilled. F~. a~ determined by the following:

2C,()fi

II'

when - s - -

F. -

II'

351 n

vr,

I

vF,

. ~ < - ~ . ~

(~y

5.2·6)

v;;:: ~.)

~60!!

.:.104=.9:,::&;;.0':.. 1>

(E~l '

when

II'

(Eq.5.2·7) 35 1n

->-I \IF., (Eq. 5.2·8)

Dodecngonalmembcrs
F.- I',[I

KL when - s C'

,

I\, = F,

II'

when -

~40 n

~--

\IF.,

I

(Eq.5.2·3) F•

F• '""'

KL when >C

,

C,. =

ru rrv"F.,

'

lA5F,(I.O-O.OO I29/ 1

(Eq.5.2-4) when

2400 - < II'- s3HU --

,IF.

\IF.

I IL

when -

I

(&1. 5.2·5)

VF.7) 374H

> --

,IF.

(&t. 5.2-11)

5

DESIGN OF STEEL TRANSMISSION POLE STRUCTURES

Hcxdec;lgonal mcmbers (be nd angle - 11.5°)

f: - ':,

".=

II'

21Sn

I

\IF,

whcn - : 5 - -

21sn

II'

412n

Vi'

,

Vi'

when - - < - , ; - -

104,98011)

F•

5.2.1.2.4 ROllnd M elllbt!I;\' For rou nd members ('Ir reg-

ular lx>lygolllll members with more than sixteen sides. the cOnlpl"e~sive S1n:s:;: shall not exceed the following:

~ W,7)

1.421' . ( I.O-o.OOI :n

.

(Eq.S.2- 12)

.

\I'

\\hcn -

,

4120

> _r;:-

v F.

(Eq.5.2·15) (Eq. 5.2- I3) where (Eq.5.2-14)

,-

"'u ".

II

",

-

..r:

= compressive stress due to axial loads; = compressive stre"s due 10 bcndlllg 1Il0menl S: F. compressive stress permitted: ilnd Fb bending slres~ pcrmilled. J~

where

,.•

mine the compressive ~t ress permitted . Sec Table 5.1 10 determine which equntio ns shall be used based on thi s bend lingle.

D.

lihalt be used unle!!iS il exceeds ~/ . in which ~'ase it shall be Ilike n equal 10 4/. Fur ~cctiolls with two or nmre plies. Ihis cnlenon shall be snlisl"icd for each ply. TobIe 5- 1 ~ umlllnrizes Ihe equations that shall be used to determine the compressive lilress permitted ba~ed on bend angle and axial slress. Eq~ .

5.2-6. 5.2·7, and 5.2-8 shall be used fur rccl:Ulgular members. The nut width associated with each side shall be treated SCp..1ratcly. If the ax ial slress•..r:. is grcmer than J J...!!ii (6.9 MPn). Eqs. 5.2-9, 5.2- 10. and 5.1- 11 shall be used.

5.2.1.2.3 Poll'golllll EllipliCllI M('lIIbers T hc hend

angle and nat width a,socimed with elliptic;11 cross ~ect i (l n s arc not con~tnnt. The snl ullcst bend angle a~.~(x:inted with a p:uticular nat slmll be used 10 cleter-

3800(1)

/)"

F,

f

---<-~

F

•

, ..~ =

.•

/

~

45"

~

30"001 < 45 but < .10"

> 225

< 22S

!SO

t l s i (6.9 MPa) l~i (6.9 MPa)

> I N.A.

N.A N.A.

12.ooo
F.

o

6000 1' whcn ......!!<---

F•

/

(Eq.5.2· 17)

1

P,

(Eq.5.2- 18)

1800d)

0.70''', .. - --

D"

when

6000<~ - - < D. -$ "~. /

(&1. 5.2- 19)

where 0" = oUl~ide diameler of Ihc tubu lar St.-ction (0:11-10nat outside diame1er for pol ygo nlll members); wall thidness; :lIld II) 1.0 for F" ,..... or "i. in I..,i (6.90 for F,. ,. ~, or F. in MPa).

TA 8 LE 5· 1. Compressive S lfl'S..'i Permitted Based

Ol!: ~5·

CEq 5.2· 16)

950(1)

In delcrmining w. Ihe actual inside bend roldlUs

RCflt! Anglc

F•

I

F" = 0.75F, + - -

when

5.2.3.2.2 Rcc/angll/a,. M embl!l'S

\\hen D " ~ 3800(1)

F. - F,

"pcl'ilied minimum yield slre .. s; compressive siress permittcd: nat width of a side; wall thicl..ncss: 1.0 for r-. o r F8 in I..si (2.62 for F, or F" in Mpa); and 1.0 for ' :" in k"i (6.90 for /;" in Mpa).

0 11

Ucnd A ngle

Equ:uion 5.2-6.5.2-1.5.2-8

5.2-9.5.1-10.5.2-11 5-2-9. 5-2-10. 5-2-11 5.2-12.5.1- 13,5.2-14

5.2· 15,5.2-16.5.2·17,5.2-18. S.2-lll

ASCElSE14g,05

5.2.-' Shear 'nlt! shear stress rc~uhing from applied shcar fOrl'es. t or~ion;J1 shellr, or
VQ

T,

-+-s P /11 J ~

where F, - O,58F,

(Eq,5.2-20)

where

I" f, V

Q I T

~Ix."dlied minimum yidd ~tresS; she-ar stress I>crrnillcd; .. hear force: momcll1 of section about neulral moment of inertil': wrsional moment;

axi~:

b

di
5,2,5 Uending TIle sIress resulting from bending shall not cxcced either of Ihe following : Mr' s ,.., I '

(Eq. 5,2-21)

0'

Me

-I \\0

"

f" •

,......... cumpressivc strcs~ pcmlillcd by Section 5,2.3,2.1: F~ bending siress pcrmillcd by Section 5.2.3.2.4; I, , tellsile mc~s pcrmiued by Section 5.2.2: axial forcc on mcmber: I' cmss-sectional (lrea; A M, = bending moment abuut X,X axis; bending momenl about Y- Yaxis; M, moment of inenia nboul X·X axis: I, moment of inenia about y. Y llxis; I, dist'lIlt'e from Y,)' ;!"(is to point where Slress I~ <', checked; distance from X-X :JItd .. 10 point where slress is checked; 101011 l'csull11nt shcar force: V Illoment of ~edion about l1I.:ulrlll axi·,: Q moment 01 inertia: I T - 10Nional moment: J = torsional constant of cro~s section: distance from nelllr.11 axis to point ...... here stress is checked; and - wall thickness,

",

J = torsiollnl constant of cross section;

,

where

(Eq. 5.2-22)

,

The bending ~Ires .. (Me/I) nntl <:hear s t rcs~ portions o f Ihcse cquat ions sha llb<.· absolute: vollies (i.e,. alwnys positive-). The !'anlC equation shall be u\Cd to check tension and compressiml stre~.ses. When chet:king tension, IljA i, pi)')itivc if thc mcmber is in len~ion and negative if the member is In compression. Thc cmwersc is true when checking comprcssion.

her.:

P, = tensile slress pcnnillcd: compressive stre~~ pcrmilled: I moment of incl1l<.1: M bending moment: and C .." distance from neulm1 axis 10 extreme liber.

5.3 GUYS

F..

5.3. 1 Material Prupl,'l'!iI,'S

5.2,6 Comhined Stresses For a polygonal member, the combined slress :J.I any poinl on the cross section shall nOI exceed the following:

M tl")' +3 (VQ + TC)']ill2l..,:

I' +M,e, --+-[( II I, I,

//

J

or p"

_ I,

(Eq. 5.2-23)

T he minimuill rated brel.J..ing ~t rcngth {If guys Sh:lll be determined according 10 Ihe appropri;ltc ASTM "pceificalion or as spec-Hied by the Owner. The lIlodulu~ of elasticity. H, of a guy ... hall be as specilied by the applicable ASTM specification or as specilied by the Owner. III the absence of a ~pecified value, E shall be as~ullled to be 23,000 J..si ( 159 GPa). 5.3,2 Tension The Il13XimUIll de .. ign not exceed the following :

t en~lon

force in a guy sh:11I

where P_. = n.b; RBS For a round member, the combined stress at any poinl on Ihe cross seClion shall nOl exceed lhe following:

:' + [( A

M,e, + AI,e,):!. + 3(VQ + TC)'](tn) :s F, I,

I,

'(

or Flo

J (Eq.5,2-24)

(Ell. 5.3- 1)

where I' p~,

"BS

tension force in the guy; Illaximum lension force pcrlOilled in the guy: and minimum r.lled breaking slrength of the guy. 1

DESIGN

m· STEEL TRANSMISSION POLE STRUCTURf.,S

5,.. TEST VER IFI CATION

'11is listing of suitable ~tecl~ doc!' not exclude thc of other steels that conform to the chemical and mcchanical propenics of one of Ihe listed ~pedlie;l­ dons or other publishe([ specifications. which eSlab li ~h the propenics and suitabi lity of Ihe m;lterial. u~c

Design v:.lues other than those prescribed in this sec· lion can be u~ed if subsHlllI imed by experiment:11 ur analytic .. 1 invcstigalion~.

6.0 DESIGN OF CONNECTIONS

6.2.2 Shea r St ress ill n earing Con nect ions TIle shear strc~~ for bolts ;lnd pins sh:lllllOi exeeed the following:

6. 1 INTRODUCTION The design stresses for cQIlII(:etions shall be b::l'\Cd on ultimate strength methods using factored design loads.

V .:s: F, A

For bolted conncctlOns. these provisions 'Ihall pertain to holes with diameters a maximum of 0. 125 in. (3 mm) lorger th:ln the nominal bolt diamelcr (except for anchor bolt holes). For pinned connections. the ratio of the di:lmeler of the hole to the diameter 01 Ihe pin shall be less Ihan 2. 6.2. 1 Millerials Materials conforming to Ihe following Sland:ml specilieations are suitable for U'IC under this standard: A5TM AJ25. Standard Specification for Strut'lUml Bolts, Sleel, Heat Treated. 120/ 105 ksi Minimum Tensile Strength; ASTM A325M. Stanlinrd Specification for Structural Bolt~, Steel Hem Tremed 830 MP;l Minllllulll Tensile Strength IMelric1: ASTM A307, SI:llldard Spccilieation for Carbon Steel BO[ls and Studs. 60.000 psi Tensile Strcnglh: ASTM AJ54, Sl;lndard Specifiealioll for Qucm:hcd and Tcml>crcd Alloy S!{.:cJ Bolts, StLl d ~, and Other Extcrnally TIlI'eadcd Fasteners; ASTM A39"" Standard Spccificmion for StL-el Transmission Tower Bolt~. Zinc-Coaled ;lnd Bare: ASTM A449, Standard Spccifie::ltion for Qucnchcd and Tcmpered Steel Bolt~ and Studs; ASTM A490. Standard Spedfie:.lion for Slruetur.. 1 Bolts, AHoy Steel, Heat Trcatell. 150 h. ... i Minimum Ten~ilc Strcngth; ASTM A490M. Standard Specification for HighStrength Steel BoUs. Classes 10.9 and 10.9.3, for StruclUral Steel Joinl"IMctricl; ASTM A563. St;lndnrd Spt.ocilk:lIioll for C:u"bo,)H and Alloy Steel Nuts; and ASTM A56JM. Standard Specification for Carbon :md Alloy Steel Nuts IMclri..:l.

(Eq.6.1- 1)

where

v6.2 UOLTt<:D AND "INNED CONNECTIONS

where p. = 0.45 ,.-•

A A, A, "-,

p..

shear force (bolt 01' pin); either A, or A,; gross cross·sectional ,'lrC;l of the 'Ihank (bolt or pin); cross-scctiOll::l1 area at roOI or the threads; shear ~tres~ pemlilled (boltlJr pin): ;lnd specified minimuill tensile st ress (bolt or pin).

A, ... h
6.2.3 !Jolts Suhjl'i:t to Tension The value!> for tensile sire .... , proof-load "Irc~~, and yield stress ... hall be the ,>pee.lied minimum values ;l\ given in the applicable ASTM 'I>ccilicmi(ln. Bolts slmll be proportioned !'l) thm the sum of the tensile stressc,> caused by the applied external lOild and any ten .. ile slres~ reMllting from prying action docs not excct·d the I>crmillcd tensile !'Ircss, F,. as follow~: l. FOI' bolts h(1ving a 'l'lCcified prouf.load stress. F, 'Ih;l[] equal the lowest value of ASTM proof·load stress by Ihe length-measuremcnt method. or O.83F. (where F. is Ihe speci fied minimum tensilc stress of the bolt). 2. For bolts with no sp<.ocilied pnMJf-load ... Ir('~ .. bul a specified yield slrc'1.s. f , shall equal thc Im\-cst vMlle of F,., where F, is Ihe specified yield strcs.~, or O.83F" {where I~, is Ihe ~1)C(' ili ed minimum tell~ilc \!rcss (lr the holt). 3. Fur bolt .. with no ~pecitied proof·[o:td ,Ires, or yidd stress. F, ~h:lll t."qu;ll 0.60/'., where F. is the ~pccified minimum ten,ile ~lres,> of the bolt.

T, A,

,.,

(Eq .6.2·2)

ASCEJSEI 48-05

The stress :1TCU, A" is given by

nnd

A, where

T.

o 11

nomin:ll diameter or lhe bolt; and number of thrcads per unit or length,

F~ F~I _ (J, )2 ,.~

-io)'

of

(Eq.6.2-4)

where P,

J.

shear stress I>crmined defincd in Section 6.2.2: tensile strcss pennillcd deli ned in Sct'lion 6.2.3: ,lnd ~hc
Thc t'ombincd tensile and she:!r stresses !;hall be t section in the boll.

6.2.5 nearing Strtss in nulled Connections The maximum bc
P d

r"

]

(Eq.6.2-9)

2

2.67 if

(Eq.6.2- 1O)

where

P

ro rce transmitted by the bolt: minimum edge distance. pilr:llieitu thc load, from the center or the hole to the edge of the mcmber: If = nominal diameter of the bolt: dh = diameter of the hole: me mber thickness; I"~ sl>ccified minimum tensilc stress of the member: F, specified minimum yield stress of the member: and ~. = minimum center-to-center spacing between bolts. L,

6.1.7 Beurillg Slr{'ss ill Pinncd Connections The tn
(Eq. 6.2- 11) where I~,

where

lb.

[p

-1 - - - 1 <1 2 0.581--,1 h

Minimum bolt sp
bolt tcnsilc forcc;

6.2.4 Rolls Subject to CombillL-d Shear and Tension For bolts subject to combi ncd shear and ~en s i on. the pcnnillcd uxial tensile ~I rc ss in conjunctiun with shear ~tress, F~"j' shall be

F,.

L,

(&1·6.2-)

bearing strcss: fort'c transmitted by the pin; if nominal diameter or the pin; / = mcmber thickness; and "-" sped lied minimum tensile stress or the member.

P

bearing ~tress; fmce transmitted by Ihe boll; nominal diameler of the boll; mcmber thickness: lind spcti lied minimulll tensile l>tre s~ (If the member.

6.2.6 Minimum Edge Distances lwei nolt Spacing ror UnUL>d Connections Minimum edge disl1I nces shall satisfy the following conditions: L

L2P

~­

•

"',,1

L , = 1.3d

L, =

I


+2

6.2.8 Minimum Edgl" l)iSI
L'= ~[O.7~F,t + IJh]

CEq. 6.2-6) (Eq.6.2-7) (Eq. 6.2-8)

(Eq.6.2- 12)

and L = -1

,

[p

2 0.3751'",,1

+

]

d

(Eq.6.2-13)

h

9

DESIGN OF STEEL TRANSM ISS ION POLE STRUCTURES

where p

L,

-

L,

d.

,., ,.• -

foree tran ~ mitted by the pill: minimum edge distance, parallel to the load. from the center of the hole to the edge of the member; minimum edge di ~ l ancc, perpendicu lar to the IO:ld, from the eellh:r of the hole to the edge of the member: diameter of Ihe atwehment hole: member thickness; "'pcl.:ilied minimum yield ~trcss of the member; and ~pecined minimum ten~ ll e Strc ..s of the memt>cr.

6.3 WELDED CONNECTIONS

6.3.1 Mntcl'illl PrOIK'rtics The l10lllmallellsilc strength of weld metals shall be based on the minimum values a .. e~ tabli s hed in the AWS DI .I. Weld mlllcrial shall be compatible with the base material :I::; specified in the AWS D 1.1_ Welding electrodes shall meet the same Ch:lrpy impact requ iremenl" a~ the hase material.

6.3.2 EfTccli\'c Area Exrept for plug and slot welds. the eO'ccli ve area of a weld jOlllt ~hu ll be equal to Ihe cffcl~t i ve length of

the weld times the eOecti ve throat Ihi c ~n es ... For plug and slol wcld~. the cCfecti ve area sh:.11 be considered to be thc nominal cross-~e ti on al .. rca of Ihe hole 01' slot in the plane o f the faying "urfilL'e. The elTecti,," length of a groove weld shall be equal 10 the width of the connected pan . The elTcctive throat of a complete penctl1ltion groove weld shall be cqualto the thickness of the th in ncr con nected pilrt. The eftel'live throallhil'kncs~ of partial pc nclf
(9.5 111m).

TAULE 6-1. Effect ive Throa t Thickness of Partial r·cncll"aiion GmO\'C Welds

Wcldlllg Proce...s

Welding Position

Shielded metnl nrc or submerged arc

Included Angle at ~ OO! of Groovc

I::JIi:Ch VC- Throot

Thld.:ncss Dellth of chnmfcr minu~ 1/8 in (.l1 mm)

All

Ikpth of chamfer

Gas metal all.' or !lux cored arc

EtC(·trogas

All

~60"

IlorizolllOlI or !lat Vertical or ovcrhcad

< 60" Ix.. < 60" but

All

> "'.

~ 4S~

? 45'

Depth of chamfer Depth of chamfer I)cplh of chamfer m m u~ 1/8 D"Plh of ch:nnfer

TARI.E 6-2. Effecli ve Throat Thickness or FI:..·c GI'OO\C Welds Ty~

of Weld

Ftarc-bc ... cl-groo\,e Flnre-V-gmo\("

Radiul> (R) of Bar or Bend

I:Jfcclive Thm
All All

S/IGH.

· Usc J / 8R for (,ja~ Metal An' \'ckllng te~.x:pt R? I /~ In (1:!..7 111111),

10

1/21<"

..nor. clI'CtIIlm& Iral~,fcr process) ",hen

In

(3.2 mml

ASCEISEI 48-05

In thc case where the b:l..c Illctal~ are or dilTercnt the lowcst grade of blSt' metal shall be used for Ihe weld design.

6.3.3 Design Stresses Design ~tn;sscs lOr welds shall oonfonn to thc 101lowing: Table 6-3-Complelc PCIlCII1ltion Groove Welds; 'lbble 6-4-Fillel Welds; T!lblc 6-5-Parti:l1 Pcneu-:ui()rl Groove Welds: and Tnble 6-6--Plug nnd Siol Welds.

strength~.

'l'A ntE 6-3. COIllI)lcIC I)enclnllion GroOl't' Welds Type of Weld & Stress" Tension

nonll~lto

COl\lpfc.~~ion TC'n~iol1

effective

Required Weld Strength Same as

:1rt'"il

ba~e

mewl

L('"e l~ '

"Matching" weld met:tlmust be \I ...ed

Same as base metal

norlllal to efTeo.:tive area

or compression parallel 10 axi.\ of weld nomillalten~ik strength of we-Id metal. eAcepl shear slrcs~ on base metal shull not e::.:ceed O.5tiX yield SlrcS.~ of hase metal

050X

Shellr un efTo.'ctive arca

Weld mcl:11 with:1 ~tri:llgth Il'vel equal to or 1 Ci>~ thnn "millchms" weld mewl may be u:-cd

"1'01' ddinnirm of Cffc.:li,c are,1. see S~c1ion 6.3.2, '!-'or "m~1<:hiJ1S" wdd mClnl, 1iel' TIlOI~ 4. 1, AWS 01 I. Wcld I1l1:t;,1 1>11<' 'trenS1h I.:\"<'I higller thnn "'mntehiJ1S" weld metal will be p.:nllined.

TABLE 6-4, Fillet Welds Design Str<.'ss

R<.'quired Wetd Strcngth Lcvel b -

Shear on eO'ective area

0.50X nominal tensile strength of weld melal. c)'cepl shenr siress on bllSC ml'tal shall nol exceed 0.58X yidd ~tress of ba~e meml

Weld mewl wilh 01 stfCngth level equal to \11' Ics~ than '"matching" weld metal nMy be used

Ten~ion

Same ill> ba.-.c metal

or comllres~ion par:1l!elto OIxis of weld


Stre.~s~

t"ffec\ ivc area

Dc~jgn

Stress

Requi~d

Weld Strenglh Lcvel h l

Same as base metal

or l.'Onlprcs~;on paralk-I 10 a::.:is of weld

Shear l)arnllello axis of'Wcld

0.50X nomillal ten., ile ~trenglh of wclUllletl\I, except .~hc:lr ~tr.,,:ss OIl ha~c metal "hall n01 exn'ell 0.58X yield ~trcss of ba.\C metal

Tl'lbion nunnal to elfcctive arc!!

0.50X nclminal tensile

~trcngth of weld metal, e::.:eept "hear stre.~s on b
-llot- delin;!;nn of eft"...:1;vC arc;t. """ Sec1ion 6.3.2. ~For "mnh:hing" \\".:1.1 metal, st.'\' 'lilhlc 4. 1. AWS 01.1 . ' Weld mcml nne ~trcngth [e'el higher than "tn~tching" wdtl 'newl will he

Weld metal with a ~trcngth IC\'l::1 equal to or leM th:m " mutching" wc ld mCI:! 1 may be u,ed

~nnl1tcd

II

DESIGN 01- STEEL TRANSMISSION POLE STRUCTURES

TABLE 6-6. Plug and Slot Welds Type ofW{'ld & Shear pamllel to fuying (Oil

effecti ve

]A·sign

Strc.'>~·

O.50X nomin;Ji ten,ile stfCllgth of weld met:1l. except ,hear .~!rc~s on ba~e mctal .~hall not c'\(:l'l'd O.58X yield ~tre~s of ba...... metal

~urfao.:es

Ml:'a)

"I'or '.kfinl[IOI1 "I' e" S~cl;on 6.3.2. 'r"()r "11l~tdllnl:" weld metal st·.., Tabll.' 4. t. AWS Dt.1 ' Wi;l\J l1)1:tal onc strength level higher Ib:1II "m:lIdling" ..... eld nk'13t

Will be

6.3.3. 1 T"rollg"-T"jckl/l!~'s Stress Mnximum design through-thickness stress sll:1 11 be 36 hi (248 MPa) for ;111 grades of steel. 6.3,4 Cil'culIlfercnlial Welded Splices Complete penetralion (100%) welds shall be used for sections joined by circumferential welds. Longitudinal welds within 3 in. (76 mm) of circumfere ntial welds shall have complete fusion through the section thickness and complete joint penetration for processes u~ing. weld metal. 6.3.5 !"lange ;l nd 8:lsc Plnte tn Pole S haft Welds Flange and base plate to pole ~haft welds shall be complete penetnltion (100%) groove welds with reinforcing iilletto sati~ry the I'cquire1llcnts for through-thickncss stresses in the nangc OJ' bilse plates. Longitudinal welds within 3 in. (76 mm) of a nange plate or base plate weld shall have complete fu sion through the section thickness and complete joint penetration for pro\:csses using weld me"ll. 6.3.0 T-joints T-joints ~h(lll sllt isfy the thickness stresses.

Required Weld Sncllgth

LC\el~'

Weld metal with n ..,trcngth level eqlt:!l

to or less than "matching" weld metal may be u....::d

pcrllllUeoJ.

have complete fusio n through the se(~tinn thil·knes.; and complete joi nt p"netratiun for processl~s using weld metal for a length e'1uallo the maximum lap dimcnsion.

6.4.2 Base and FI:lIlgc Plalc COllllcclions Flexural stress in the bilS!' or nangc plate shall not exceed the specified minimum yield stres'l. F" of the plme material. Base and nange piatc eonnCl'tinns shall be designed to resist the m shalt be designed to resist 50% of the mOlllenl cllpacity of the lowc~t strength tube.

6.5 TEST VER IFI CATION Design values other than tllOse prescribed ill this seclioJl may be used if substantiated by experimental or an:llytical investigations.

7.0 DETAILING AND fABRICATION requi remcnt~

for through-

6.4 FIELD CONNECf IONS OF MEMBERS 6.4.1 Slil) Joints Slip joints shall be designed to resist the maximum forces (lnd moment" al the con nection , A~ a minUilum. slip joinL~ ~h:J1I be dc.;igncd to resist 50% of the momcnt capacity of thc lower strength tube. Tape r above and below the slip joint shalt be the same. Supplemental locking devices shall be used if fel ntive movement of Ihe joint is critical or if the joinl Illight be subjected 10 uplift forces. III resi~ti ng. uplift forces. locking devices shall be designed to resist 100% oftllc maximum uplift loud. The fema le se(·tioll longilUdinal seam weld in the arC;l of the splice shall

"

Slrt:,;~

7. 1 DETAILING 7. 1.1 Drawings Drawings consist o f erection and shop detail drawings. If shop detail drawings arc pl'Ov ided by the Owner. the Owner shall be rcsponsibk' for the completeness and accuracy of these dra wing~. If shuI' detail dr:lwing.; are prepared by Ihe Fahricator. the Fabricator shall be responsible for CIlnveying the dimensions and details from the design :Hld contract documents. the correct ness of dirnen"ional c:llculations performed in prep
ASCEJSE.L 4/i-05 de~ign

rmd compliance with the Owner's specification. Drawings prepared by the Fabricator shall be submitted to the Owner for review. 7. 1.3 Erection Drawings Erection dr.lwings ~hall show the complete field assembly of the structure. clearly indicati ng Ihe positioning of the components, including fasteners. Th" idelllitication markings for each component sh(111 be indkatcd lln the drawing. Fastcncr~ shilll be identified by grade. length, and dinmetcr for bolts and grade and diameter for nuts :Hld wa"her!'. The erection drawings shall include a bill-ofmatcrial of all components ror the slJ1lCture. including thc wcight of cach component. The erection dmwings shall provide i n~t ruct i on" for slip joint assembly. bol t tightening. and field welding where applicable. 7.1.4 Shop Detail DrH\vin gs Shop detail dr.lwings shall show all fabric;Hi(ln requirements, including m:lteri
7. 1.4. 1 Muteri,,' Shop detail drawings shnll specify member and connection materials, such as AST M specification .lnd grade dcsigllutioJl. 7. 1.4.2 Diml!mi(lIIs llnd Tolerallces Dimensioning practices. jnt'luding to1c r~nces, shall cn~ure cornplinnce with clcnranee. oppc:Jr.lnee. ~tn.:ngth. and ns~embly requirements. Proper JIl:Jting of components detnilcd nnd supplied by one fab ricator shall be the responsibility of that fabricator. 7. / .4.3 Weldillg Welding shall be detailed in 1I(:cord
Dcwils for weathering steel structures shnll be designed to rIVoid uncoated pockets. crevices. ,md faying surfaces that can collect and retain water, damp debris, :!nd moisture. Weld bru:king for unsealed wC
7. 1.4.5 Other Requirem ellts Spcci1ic requi rements and limitations of the contrnct documents and applicable codes shall be showil on the drawings.

7,2 FA URI CATlON Fabricotiou ~hall be performed in compli:!nce with the shop delail drawings. The Fahricator shall be responsible for the means. mcthods. techniques. sequences, and procedures of fabrication. S"fcty prcc'llltions ;lI1d programs for fabrication ~hall be the responsibility or Ihe Fabricator. 7.2.1 Material The Fnbricator shall maintain a system. including re!;ords. that will verify that the structural stcel furnished meets the specified requirements. Certified (('st reports from the plate or coil mill .. and frum ,<,upplicrs or bolts, welding eJet·trooc, uud olher materials shall constitute sullieient evidell!;C of conformity. The Fabricmur shall act'lIfutcly identi(y all 1ll'lteri,,1 10 ensure proper usage. 7.2.2 Mat{'ria J Prcpllratio n

7.2.2. 1 CUlling P:uts shall be cut in accordance wilh t\WS D1. 1. Burrs or sharp notchcs that are detrirnentallO the structure or that po!';e a sc r.:quired I.ly design. If scparation occur.; during bend ing. il shall hc repai red in accorda nce with AWS D l . 1. Loosening of mill scale slwll not be t.:onside rcd a scparJtion. When hot bending is required. heati ng shall be done even ly Clver the entire bend arc:! and shall be of sunicient temperature to minirnile scpufatiorl and ned..ing down of the cross section. T he tempcnuurc used in hot bending shalll.le sllch that Ihe physical properties of the steel art: not diminished. 13

Dl'SIGN OF STEEL TRANSM ISS ION POLE STRUCTURES

7.2.2.3 I/ole.\'

Bah holes i>hall have the correct shape and alignment in accordance with connection dct
8.5 STRAlN MEASUREMENTS The Owner shall specify if any speciall>lrain determi· nation methods are rctluired for the prototype and idcl11ify those components 10 be :.train g;lged.

7.2.2.4 IdclllijiCllfiol/

All components shall be clearly marked. 8.6 AS$EMIlLY AND ERECTION

7.2.3 Welding All welding 5h:l11 be performed by welders. welding opemtOTs. and tacker~ qUlllified for the type of welding to be performcd. All welding and qualitic:ltions i>hall be in accordance wilh the applicable requirements of AWS I) I, I :md AWS 1)1 .3. Pr!;!heat and intcrpass temperatures shllll be in accord:mce with AW$ D I. I or the ~tcel manufacturer's recommendations. Longitudina l seam welds shall have 60 percent minimum penetration (except as specilied in Sections 6.3.4. 6.3.5, and 6.4.1).

The assembly method of the prototype sholl be 'lpproved by Ihe Owner. The completed teSI structure shall be erected wilhin the tolerant'es e~ t :\blished by the Owner.

H.7 TEST LOADS The Owner shall specify in the C01llract documents which load cases sha ll he tested as a minimum and if the structure is to be le~ tcd to destruction. The test IO:lds sh311 be the factored design loads.

8.0 TESTING

8.1 INTROOUCTION

8.8 I.OAD APPLI CATION

The Owner slwll sl}Ccify in the contract docuillents whidl structures or components of" structure wi ll be tested. If a proof test of a structure or strueturc component is specified. the test shaH be performed on a fullsize prototype of the structure or stl1lcture component in ;tt'cordunce with the fol1owing sections.

Load lines slwll be allached to the load poillt ~ on the protOlype in a manner that simul!lles thc in-service application as close as possible. The ,1IIachment hard· ware for the test sllil1l have the same degrees of freedom as the in-service hardware. Wi nd·un-structure loads shall be applied as conce nlfilled loads at sek:cted points on the ~tfuetu rc. Load application shall co n ~ider Ihe del1ected position of the :;tructurc.

8.2 FOUN DATIONS The Structure Designer shall approve the support COIIditions used for tcsting.

8.3 !\'IATERIA L The prototype sh:lll be made of rH:llcriallhlll is reprc~entalive of the rmllerial Ihat will be used in proouclion. Mill test reports shall be (lv(lil:lble for each m:Jjor compancllI in the tc,'lt structure. When mill tc.~t reports are unavailable, coupon tests are n:quircd. Coupon lests ~hull be performed in accord3nt~C with AST M A370.

8.4 FAURICATIQN Fabrication of the prototype sh:tll be done in Ihc slime manner as for the production structure. 14

8.9 LOADING I'ROCEOURE The sequence of load cases te~ te d ~ha ll be specified hy the Structurc Dcsigner und approved by the Owner. Loading shall be Slopped at prcselct"ted load levels to allow time fo r reading denections and tt) permit observation of the test to ched, for sign.. of structural distrcsi>.

tun

LOAD MEAS UREMENT

Lo,tds shall be 111l:asurcd through a verifiable arrangemcl1l of strai n device!' or by predctermined dead wcigh t ~. Load-measuring dev ices sh'l ll be u ~ed in accordance wit h IImnufacturcr's rceomrncndati o n ~ and calibnucd prior to and ;Iner the concl usion of testi ng.

ASCElSE I 48-05

R.II DEFLECTIONS At the locations spccir-icd by the Structure Designer

and approved by the Owner, dcrieclions of prototypes under lOtlc! shall be measured and recorded by the le.';\ engineer. Dcrlection readings slmll be Illtlclc for the "before" and "off' load conditions as well a~ at each intermediate hold during loading. All deflections shall be referenced 10 common base readings taken before the first lest IO
se rve as a foundat.ion design gu ide. It is the responsi bility of the Owner \0 ensure adequate geotechnical design.

'9.2 GENERAL CONSIDERATIONS As applicable, the Owner shall include the following in the specifications: I. Foundation type.

2. Depth to point of foundation fixi ty, 8.12 FAILURES When failure occurs before application of 100% of thc factored design loads, the calise of thc t~lilllrc, thc corrective mC
8.13 POSTTEST INSPECTION The prototype shall be inspected after testing. Welds shall be inspected in accordance with the normal fabrication procedures. Visual inspection for any signs of structural damagc shnll be conducted by the Test Engincer.

8.14 DISPOSITION OF PROTOTYPE The l.:ontract doclIment shall sl
8.15 REPORT The testing organization shall furnish the number of copies of the lest report as required by the contract document. The test report shall describe the test procedure, [CS1 results, and any remedial action taken.

9.0 STRUCTURAL MEMBERS AND CONNECTIONS USED IN FOUNDATIONS

9.1 INTRODUCTION This sec tion speci lics dcsign procedures for steel members and connections embedded in concrete or other backfill material. This section is not intended to

3. Design limit for foundation rOlation or

dellcction.

·4. Foundation reveal, .5. Coating require mcnts, 6. Grounding requirements, 7. Conceele or b"cklill "'alerial strength, 8. Corrosion protection, 9. Other special requirements.

9.3 ANCHOR 1l0LTS Anchor bolts shall be desig ned to transfer the tcnsile, compressive. and shew' loads to the concrete by adeqlwte embedment length or by the end connection. Impact properties in thc longitudinal direction of all anchor bolt materials shall be determined in accordance with the Charpy V-notch test described in ASTM A370 and, at a minimum , shall meet {he requirements of 15 fl-Ib (20 J) absorbed energy at a temperature 01" - 20° F (- 29°C).

9.3.1 Bolts SUhject to Tension The tensile, proof-loud, and yield stresses shall be :;;pecilied minimum values determined according to the ASTM specification for the material involved. Bolts shall be designed so that the SUIll of the lensile st resses caused by the applied external load and any tensile stress re!)ulting from prying action does not exceed the tensile stress pcrllliLted, F,. as follows: !. For bolts having a specified proof-load stress, F, shall equalthc lowest valuc of ASTM proof-load stress by the length-measurement method or 0.83F". where F" is the spccified minimum tensile stress of the bolt. 2. For bolts with 110 speeilied proof-load stress but a specified yield stress, F, shall equal the lowest value of F.l" where F, is the specilicd yield st ress, or O.83f~ . where F" is the specified minimum tensile stress of the bolt. 15

DESIGN OF STEEL TRANSMISS ION POLE STRUcrURES

For bolts with no '\J>Ccificd proof-load stress or yield stress. I': ~ha ll equtll O.60F~. where I'~ i~ the specified minimum ICI)~i l e ,!.lress of boll.

for the thre
(Eq. 9.3-"

where

L, where the

~t ress

minimum development length (embedmcnt) of anchor bolt; and IJ = basic development length of :mchor bolt.

nrea. A,. is given by W (

A - -

s

4

0.9743)' d - /I

(Eq.9.3·2)

where T,

(I II

-

The ba~ic follows :

de~clopment

length for the bolt shall be as

for ban; up to nnd including #I II (35M). u<;c the larger or

boll ten~ilc force; nominal diameter of the bolt; and number of threads per unit of length.

1.27rA lr f',

9.3,2 Shear Stress 111e shear stress for .mehor bolts shall be dell:rmined a~ follows:

Vi'

(Eq.9.3-6)

0'

(Eq. 9.3-7)

~ :s: F, -. 0.65 F, A,

(Eq. 9.3-3)

for#14 (45M) bars

where 1 =

V A,

-"

P,-

F, d

shCOlr foree on bolt ; Tt/ 4((1 - 0.9743 / ll f . tensile "tress area of bt)1t; shear stress permitted: specified minimum yield stress of ixlll m'ltcrial ; nominal dillmeter of the bolt: tlnd number of threads per unit of length.

9.3.3 Combined Shear and Tension For bnlh subject to combined shear nnd tension, the pcrm;lIcd axi;!1 tensile stress in conjunction with shear stress. I;~,~ shall be

_ r- ~I _ (f'F, )'

I'1 ( ' 1 '

I~

J.

for HI8 and HI81 (55M)

where

A, A '''''1',11

-

F,

(Eq. 9.3-4)

shear 'tress pcrmiued defined in Section lJ.3.2; ten<;ile st ress pcrmilled defined in Section 9.3.1: and ..henr stress on elTeclive area.

"r --

e'I' a

The combined tensile and ~ h e"r stresses shall be ta ken at the same cross section in the boll.

#

9.3.4 Dc\cJopmclll Length The Owner !>Iwll provide 11 minimum or 3 in. (76 mill) dcar concrete cmer. 111C development length

y

16

-

(Eq . 9 3-8)

ba~ 3.52~)F,

I, -

/,'

where

r,o

~

2.69E"· , ,... VI,'

Vi:

CEq. 9.3-9)

gros!> nrea or anchor bolt; fequired len<;ile S\l'CS~ Orc:1 or bolt; spccified minimum yield "tress of ancho r bolt; !.pccified comprc<;\ive ~t rength of concrete ;
ilnd A ,,~~.IA •.

ASCEISEI 4S"()5

9.4 DlR ECT·EM IlElJDED

I'OLE~

calculations. lotrcSS analyses, and the F:lbric:ltor's dr:lwings.

The embedded section shall be designed 10 resist the ovcnul11ing moment, ~hcar. and a~ lal toads. The length of the ..cction of the pole below the groundline !>hall be determined using a lateral rcsi"13ncc approach. The Owner ~ha ll be responsible for supplying the Structure Designer inform:ll ioll regarding the cmbcdmcllI depth. allow'lblc foundation rol<Jlion, imu design point of fixilY of the embedded section.

~.5

F.l\mEODf:D CAS INGS

The

cll~ing

iohall be designed to

The length of the embedded

fc~isl

cil~i n g

all

dc~ign load~.

below the gmund-

line shall he determined using a lateral resistance approach. The Owner )'h311 be responsible for supply· mg the Structure Designer inforll1aliOIl rcg:lrding the embedment depth. allowable foundation rOlation, dcsign pOInt of fixity of thc embedded section, viblll' tmy ill~tnllat;nn forccs, vibratory device allachmcnt, ,md method of steel polc allachrnclll.

9.6 TE..';;'r VERIFI CATION Dcsign va lu t.'~ other th,m Ihose prescribed in this set'· lion may be u~c(1 if subslillltialcd by experimental or analytical investigations,

10.2.2 Mllteria ls The quality assurance specilicatioll shall specify the requifCments for review and agreement on the Fabri c
1f).2.4 Nondestructive Testing The (IUality assurance ~t>ecincation sh:l ll indicate the rc(luiremcnt for acceptanCt' of the type and procedure ur nondestmctive testing ;md in~pcctinn programs employed during c:lch step in the fabrication proces~~.

10.2.5 Tulerances F:lbriC;ltioll tolerances ~ hall be specified :md agreed upon by thc Owner :lIId the FabriC:ltor.

10.0 QUALITY ASSU RANCE/QUALITY

10.2.6 Surrace Coatings

CONTROL

When painting is spc(·ificd. the p:lint sy~te L11 . pro· cedures, and methods of application shall Ix: agreed upon by both the Owner and the Fabriclltor. T he selected pai nt sy"lelll shall be suit:lble for both the produt't and it .. intended exposure. When galvani/jng is "pccifiell. the procedure and fxilitics "hall be agreed upon by the 0\\ ncr :lIId the Fabric.llor. In ~pect i on right!> ami privileges, procc· dul'cs. and :lc(.;eptan(.;e or rejection of galvalli/cll steel rn:ltcriul ,hall conform to ASTM A 123, A 14). A 153. and A)85 a~ applicable. Whcn Illctalli7ing is ~pcL:ified, the procedure and r:lcilities shall he III aceordance with the coating vendor's rceorlullendatlon.., and be acceptable to both the Owner ami the Fabricator. When bare weathering lotecl is ~pecificd. the neeli for :md degrl!e of b l a~t cleaning the ~ tccl shall be ag reed upon by the Owner and the Ftlbricator. T he quality nssu rance ~pccifit'iltio Li ~ha ll c .. tab1i ~h in~peclion righb. privileges. and pr('lcedure~ ror evulu· ating the ~urrace coating,

10.1 INTRODUCTION

111e contmct between the Owner and the Fabricator shnll state the rcspon!;Lbility of c:JCh party and the condilion~ under which the work will be 3CCCpled or rejected,

10.2 QUALITY ASSURANCE Qunlity a~ .. unUiCc (QA) is the n:~pon<;.ibility of the O ..... ner. The l>pccifying and implemcntation of qU:llity 3s~urance requircments by the Owner shall not rcl kye the FabricUlor of responsibility in producing a product in accordance with this standard.

10.2.1 Dl'Sign lind Drawings The quality assurance ~pccification ~ha ll indLcutc the pmcedllfC for review of the design concept. design

17

DE.<)IGN OF STI::EL TRANSMISSION POLE STRUCTURES

10.2.7 Shipping When receiving materinl, all product~ shull be in~pected for 'Iuppi ng damage prior to accepting delivery. If damage i~ apparent, the Owocr shall immediately !IU1ify both the delivering carrier and the Fabricmor

10.3.4 SnrrllCC Coating Inspl.'t'\ ion The Fnbric:.tor shnll ched.. product prcparation and ctxlIi ng thickness 10 e nsure Ihat the minimuill dry filmthicl..ncss fC{luiremCnl' of the ("ooti ng specificuI;on are met. Visual IIlspcction sh,llI be perrormed ror the pU'l)Ose of dctecting pinholes. cr:lcking. and other undesirable chnmcterislics.

10.3 QUAL ITY CONTROL

10.3.5 Weld Insp4!ction Quality control supervisory per'onnel shall be certified weldlllg insp<'t·turs (CWI) in nccordance with the provisions of AWS QC I. Weld IIlspcclion ,h:lll be perrormcd III accordance with the requirements or Section 6. Inspection. Pall C. of AWS DI .1. Personnel qualification rur nondestructive weld tcsting shall be in 3ccord:!nce with Section 6.14.6.1 of AWS DI.I . Complete pellctration welds <;hnll be 100% inspected by clther ultrn<;onic (UT) or mdiogrnphic (RT ) mcthods. Appropriate illSI>CClioll pr:lctice" shnll be used 10 ensure th;Jl rclluircd penctration is ndlie\cd For g.tlv;lIIi/.cd member:. wilh large T-joint conncc· tiolls. such as bn"l.: plates. nnnge plme;;. etc., ultl ... ~on ic nondC<;lrUClive weld testillg 'hnll be perronned on 100% of all such joints, not only berore, but also aticr galvaniling to ensure no cratks huve developed. Any i ndit"ation~ found with thi~ te~t shall be ground smooth and in<;pectcd With magnetic panicle meth()d~. Any positive indic:ltions rollowing this inspection shnll be repa ircd ,lnd rci n ~ pcc tcd , :lIld the linish sl1
Quality cOlllrol (QC) is the rcspon~ibi li l)' of the F:lbriclltor, The Fabricator !>hall have a QC progr:lm conshllng of u wrillen document lhat establishe, the procedures and 1llethods of opcnllion thOlt urret'l th..: qua lity of lhe work . The QC fUllct ions shall be clearly defined and available for review and approval by the Owner. The QC program shall \'erify that lhe product mecb the level of quality est"blished by the Fabricator's ~lalldards and the Owner's specification. The QC progrJ1ll Sh311 eslahli .. h procedures for maint:!irung records of :.11 pcrtillelH information un all components. 10.3. 1 Mllteriuls T he quality control prognlm shall:.pecify the review requiremcnt" of all materials that are used in the fabncatlllg and coating of the. complele slructure, all millle:;1 reports for malcri:!1 t'oillpliance, all m:lteri :ll suppl i..:rs f(lr their manufncturi ng procedures illld qUlllily n:l11trol programs. ilnd all welding elect rodes. 'niC Frabricator shall m:lintain :l <;ystelll, including 11.'CQr
10.3.3 Dimcnsiolllill nspcclion Struclurnl compone nts shall he inspectcd for dime nsionnl compliance 10 determine (.·onformonce with dClllil drawings and eswbli"hed tolcmnces. When :lpplicable. the Owner ~ha ll sJll-"'Cify shop ras~mbly requirclIle1lt,.

10.3.6 ShiplIlclll llnd Storage The qu:,lily control pmgmrn ... h:lll provide procedures that Will prevent dam ngc. los,. or dClcriornlioll to the q ructurc. dunng ~Iorng(.· and "hipmen!.

1J.(J ASSEl\'I6L\' AND EREC I'ION 11 . 1 INTRODUCTION Thh section co\'ers the assembly and creclion re(luirclllCnts for stecllrnnsmi"sion pole ~tructurc.s.

11.2 HANOLING Poles. pole <;cclion~. crO""anm. :lIId other structural elcmcnt, .. hall be liftcd nnd 'Iored in such a lTl:lnncr

a~

ASCEISEI 48-05

to prevent c/i.ccssive dellcction, stresscs, and bud.ling. Sections thal arc distorted. buck lcd, or permancntly denccted shall nOl be in~talled. The Owner shall contact the Structure Designer 10 verify acceptabi lity or membc~ with :.uspccted d:unage.

J J.3 S INGLE POLE ST RUCT URES Assembly shall be in accordance with the erection drawings .md requi remcnts of the Owner.

ILJ.J Slip Joints Slip joints shall be ilssembled in ilccordance with thc Structure Designcr's requi rements as to method. eigner for review of acceptability.

11 .3.2 nolled Flange Joints Mnting surfaces shall be c1e:mcd of all foreign mailer prior to assembly. The boll s shall be inswlled 10 !mug-light cond it ion in a sequence to ensure thc proper alignment or Ihe IWO pole sections. Followi ng snug lightening, the bolls shall be tensioned in accord.mcc wilh Ihe Structure Designer's rct.:ornmend;lIions using 1I ~imila r tightening sequence. In the absencc of specHic tightcni ng rCC()lIllllend:lIions, the ""Iurn-of-nul"" method as desl'ribed in Rescan.:h Council on Structural Conncctions "Spccifiralioll fo r Structur:ll J oint~ Usi ng ASTM A325 or A490 Bolts," Section 8.2.1. shall be employed f\)r fastener tensioning. 11.3.3 AUachments to Pol(" Sections Installation of crossanns and olher au:u::hlnents to the pole :.tructure shall be in accordllllce with the Fabricator's recom\llc n dati() II ~. 11.3.4 Ercl"lion of Ass("mbled SlruCiurcs A<;scmbted structures with slip joints shall have the ..lip joint.~ temporarily secured prior tt) Ii rting to prevent Ihe pole seclions from separating duri ng the erection opennion.

11 .4 fRAM E TYPE $l'RUCT Un ES TIle m:sembly and crection procedure for fra me structures ~hall be in accordance with the Fabricator's

rccornmend:lIiolls and thc requirements list(:d in Scct ion I 1.3 e/i.ccpt as modificd by this sect ion.

11.4.1 Slip Joints in frames Slip joint con nectio n ~ shall bc assembled as described in Section 11.3. 1. On multiple leg structures. Ihe assembled leg-length differential shall not excced the practical ndjuslment Icngth of the fou nd al ion sy .. tem. 1 J.4.2 E rection Erection of frame siructures shall be in accordance with the Fabricator's recom mendations, including the u..e of temporary braces or rnembeni. a~ requi red to prevent damaging or oVlOrstressing members and con ncctions during the in.~tnllation procedure. All slip joints shall be restraincd to prevcl1l scparJ.tioll of the joi nt during structure erection.

11.4,3 Uolted Frame Conn("clions Boiled framc joi nts shall be a~sel1lbled wilh fasteners loosely boiled to permil movement in the joi nt during in~tallation of addi tional fm llling. Bolted joi nts shall be tightened after cumpletion of !>t nlclU re ereclion in accordance wilh Ihe Stru(·ture Designer's recommcndation.

11.5 INSTALLATION ON fO UNDATION 11.5. 1 Anchor nolt Ilnd BasI.' Platl.' Ills tall ~llil)n Inst allation shall be made. in such a mall ilcr as to ensure Ihat till anchor bolt nuts are tighteneci lO both the lOp ,lIId thc bottom of the pole base platt! in ,U;COfdance with the Structure Designcr's rccollllllendations. 11.5.2 Direct-Embedded Poles The .lOnular opening
11.6 G UYING 11.6.1 Guy Anchor Location Guy anchors shall be installed at Ihe I()(;ations specified by Ihe Structure Designer and approved by the line designer. If fiel d conditions prevenl the inst:lllatiull of any anchur at Ihe specified location, the Siructure Designer ~h:tll be con.~ u llcd to prov idl' an acreptablc nlternate location or other specific measu res. 19

DE.,)IGN OF STEEL TRANSM ISS ION POLE STRUCTURES

11.6.2 G uy Installation InSlall ation and tenSioning of guys slmll lx! in accord:lIIce with the require ments of the Structu re Designcr.

11.7.3 Coal ing Repair Per the Owncr's approval. all d:lI1ltlgcd areas or protcctivc comi ng shall be repai red in accordan<:c with the coali ng nHlnufAeturcr·s recom mendations.

11.7 r'OSTERECTION PROCEDURES 11.7.1 luspcctiuu StrU(;turcs shall be inspected lor proper tightcning or all boltcd joints. Clmdition of protcctive coating. and venical alignment (plumb or rake).

11.7.4 Unloaded Arms Unloaded arms shall be eval uated by the Structure Dcsigncr ror susceptibility to damage from windinduced oscillations. Remedial measures to reduce ust·illation nwgnitudcs shnll be employed if dnm:lge is considered likely.

11.7.2 G rounding Insta llation of illl required structure groundi ng sh:lll be completed promptly following structure crc<:tioll.

11.7.5 Hardware I nsta llatiUIi Conductor dampc-ning devices and/or spHcers for bu ndled conductors. if required. shall be instil lied <.Ifler condut·tor stringi ng is completed.

20

COMMENTARY This commentary is not :l pm1 or ASCEISEI 48-05. II is intended for infonll:llion:ll purposes only. This infonnlllion is provided as explanatory and SUppicIllcm3ry rnatcri! in applying the recommended n."'(juircmcnts. The sections of this CQlllmc nt;u"y are numbered 10 corrcs)X)nd 10 the secti ons of the standard \0 which they refer. Si nce it is not 1lC1.'cssary [0 have supplemen-

tary material for every section in lhe standard, there ; U'C gaps in the numbering sequence of th e commcmary.

C4.0 LOA DING. GEOMET RY, AND ANALYSIS C4.2 LOADING

C4.2. 1 Fnctorcd Desig n Loads The ovcrlo:lcI ftlClors specified by Ihe National

Electrical Safety Code (NESC) arc load factors according to lhe terminology of this ~ t:md a rd. The ASCE has developed information to 1Iid ill the seicl;tion of load~ for u"illlsrni"sioll linc stru(,LUre~. "Gu idcli lies for Eleclriefll Tr.l.I1smission Line Struclural Lnading:· ASCE Mnnua l ~ and Repol1s on Engineeling Pr:lctice No. 74. presents a reliability-based methodology for developing trall<:.rnission line structure loads. Other methods for selecting loads also may be acceptable where utility companies have established procedures that arc based on yenrs of successfu l opcfllting experience. C4.2.2 Loading Considera tions Prev;lil ing pr,lctice and most state lnws requi re that tr..U1smission lines be designed, as a minimum. to meet the requirements of past or current editions of the NESC. When evn luating potenti;ll ."truciu re loading crilenu. the Owner should consider the followi ng sources of information:

unbalanced longitudinal loads during conductor/ shield wire ~ lrin g i ng. thc need for allnchmenl provisions for structure lirting nnd hoi sting material stich as insul
C4.2.3 Load Expression The Owner should transmit spc!;i lk loading cri leria to the Structu re.! Designer in the form of load trees. utilizing a single ol1hogonal coordinate system as shown in Fig. C4 .. 1. These loading criteria shou ld ex press the magnitude, directil.)n. and point I.)f appliclItion for each load and load case. Con(\ue\or and shield wire loads should be shown :II thei r appropri;Jlc ,llIach .. ment points. The weight of in s ulatOJ~ and hardware should be included in these load",.

1. lndividuul utility plan ning criterin will usually dic-

tate spcdfic conductor and shield wire sizes. 2. Minimum Icgblated laudi ng conditi ons urc specified in UPI)l icnble nnlional. stnte, und local codes. e.g .. NESC. California GO-95. and Calind iull Swndards Assocint ion (CSA-22.J). 3. Historic:!1 dirnatie conditions in the utili ty's service area may indic:lte loads in excess of legislated 101ids. lllese mny inelude wind or ice. or :lIly CO Il1 bi nation thereor, at a speci fi cd temperature. 4. Ux:al termin and line routing procedures will dctermine the individual structure orientation criteri:l. 5. Indi vidual utility policies lmd proccdu res will dctcrmine spcd lic const ruction lind maintcnnnce requircmcnts such as structu re stability prior to conductor/shield wire instnlbtion, the potenti;}l for

I' LA'

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"J.o~GJn I>rl'l,\L ' 1· _Tl, ,\1

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I; l b VAllU ...

FIGU lm C4- 1 Recommended Load Tree For mat.

DESIGN OF STI:.:EL TRANSMISS ION POLE STRUcrURES

TIle magnitude nnd direction of wind on the 'itI1lClUre <;hould be. defint:d by the OWllef. Shape and height cocllit'iems should be included in the wind loading or lii>lL"
C4.J GEOMETRI C CONFI GURATIONS C4.J. 1 Configuration Considcl'ations The Owner should detcnninc the preliminary structure geometry bllse(1 on .111 llppropri:ltc te('hnical :.lnd economic eval uation of the electrical and meehan· ical pcrronnancc requirements. GCller.llty, transmii\sioll !>lruChlres Illay be cla!>sified :lS one of three types: !>lIspensiotl. strain. or dead-cnd. Suspension structures lire thost· in whidl t"ontiut'tors and shield wires pas, through and are !>tlspcnded from support points. Strain ~trUCtu rcs :\I"C those in which t·onduclors :\Ild shield wires :Ire allm:hcd to the Slructure by IllC:lns of bolted or cOlllpres:;;on de:ld-end fitting~. These structure,> :lre designed to support intact, b:lsically e(lua1. longitudin:ll load~ on both sidcs of the structure. Dead-end structures utilize similar conductor ilnd shield wire nllachmcnt methodi\ as utilized on <;train structurc,'i. Ilowever, dead-end structures are designed II) i\tlpport intact unb:lhtnccd longi tudinallo
22

C4.J,2 Structure Types The previously described Slructure types mny 01i\(I be cmegorized as either "self-supported'· or "guyed:· Selr-supported struclure:; have sul'fieient strength and stiO'ness to :'Uppol' the design loads without ully guy 'iUpport. Guyed structu rcs rel y on guys for load dist ribution. stiO·ness. and ~tubility.

C4,4 M ETHODS OF ANALYSIS The responsc of" tubulnr ~t l1l cture subjected to factorcd design loads is generally nonlinear. Geometric nonlinearity (also called second order elreet or P-Delw elTcct) results from di~pla eemenls thut can be substantial. Material no nlinearity Illay ",x:eur in the behavior of the ~ tecl material, with localil/:d yielding taking place. Localiled yielding m:ly even take place at load levels less than design loads because of stresses induced during Ill
C4.4.1 Slrtlcluf.

ASCElSt:.1 ,'11-05

The ona l y<;i~ ~hould have the nbility to predict dastic irhtability phenomena: i.e .. the tructurc. The analysi1> ~hould include the and moments "houlCctional properties of commonly u~ed tubulur members cnn be appl\)Ximaled by the fOnllUlae in Appendix II. Guys nmy be modeled as straight t e tl ~ioll-only ban;, prestre~sed if desired. or as a c;lblc element mdudmg the actual prestress in the guy. If the ~trut'­ lure i" dc~igned utlli/Hlg the reduced moments resullmg from pre~tres"ing the guys, the Owner's assembly :md erection specifications should require compliance with Ihe~e assumptions. For funher information sec Chapter 5 of "Design of Guycd Electrical Tr:msmission Structures," ASCE Ml1nu:ll~ nnd Repons on Engineering Prncticc No. 91. If foundation /llmelllent is of conccm, tltl' model should be ublc to ac(:ommodate 'l)Cdficd displul'clllcnt Of rotation at the structure base, or cunncctillll to found:llion cielllellls, The efleets o f :leoliall vibrut ion of the s tnl('ture.~ or Im':IIlIJcI"; undlhe resulting fatigue "trcss on the Stmctul\' (Ir members should be cun~lde r'ed . Damping opllon" or rt.",onllnendatioll~ \huuld be provided to the

Owner whcr;:. appropriate. In licu of a cornprehcn~ive engineering ~nalysi" of a ~ truc turc or member, the inSI;ll1ation (If the conductor or 'hicld Yo ire can nor· mally be considered ali an effcc\i\'e tlle:ms of SUppl"C!o~­ ing these vibr;ltion-;.

C4.5 A I)DITI ONAL CONS IOEn.ATIQNS ('4.5. 1 Strutillmi SUllport

The degree of ~upport provided by "tntcture foundations can h:we a signific;lnt eO'ect on the design of a structure becnuse of foundation rOIll\ion or di splacement. If foundatnln rotation/displacement allow.mer.:" :Ire specified. the Owner should e~tablish the performance requirements (or the structure. ~uys. and found:.tions. In determining this \':llue, ae~ thctics. dcctrit:al dear-mces. a'ld the ability 10 rcplumb :I stl1lcturc should be con~ldcn...d. C4.5,2 Design Rc.sll'icliolls Structure Shippi ng Icngth and weight rc ~trictio n s are usually influcneed by con~ tru ctjon site conditions and material handling limil:ltion-;. Stl1rclUrc dlan"lCtcr, l;lpcr, and del1cctioll rc~tric · lions arc usually innucnccd by the desin.:d appear;lIIce of installed !otructurc5. Line angles and unbalanced phase ;Irrangellwnts can create luading ~itu:,tlon-; that will calise a ~ Iruc t llre 10 deflect noticeably. There arc sc... crnl methods that L-an be u"cd to minimize Ihese efleets. One Illethod is to camber the ~ll1Iclu re during fabrication to offsct the I1nticipated deneetion under IOild ~o that it will appc:rr str'lIght and plumb aftcr installation. Another mcthod i~ to mke the struc{ure during installation. The dencclioll :1t the tOp of the ~lrUCturc is dctermined, :lnd the pole is tiltcd:1 corre· sponding amount so that the top of Ihe ~truclure i, :It a speciDed position in relation It) the Mructurc at groundhne. To catnbrr or rnke a struelUrc. a specinl lond C:lse, usually thc "normal" or '·c... eryday" 10:ld on the !>tru~·· ture. ~houl d be specified by the Owner. The struuurc finish is :I factor thm influences the design and fabrica tion of the structure. The most corn· mon ,ll1lcturc Dni"hcs aTC hot dip galvanil.ed. \\-e;lIller· ing. pnintcd, ZinC silic:lte coated, and metallized. TIle !>election of a finish IS normiJlly rnnucnced by environmental expo~ure, appeal1trlcc, (lilti regul:ltOl)' requirements. The deterllllll:ltion of the shafHO-sh:lft connection is normally based 011 the type and magnitude of ~tI1lC· ture lo:.din£. Sh;.tl"ts loaded in bt-ndll1g or comprc~"i()n are normally designed utili/ing a slip Joint connel'tlOn,

2J

DESIGN OF STEEL TRANSM ISS ION POLE STRUcrURES

whereas shafts loaded in uplift, or guyed structures with axial loads gfl!ater limn the Structure Designer's rccollunended j3cking l{)Ix:e, normally Uliliz.e a bolted l1:lIlge connection. The type of 1(lundati\JIl is usually based on ec()nOlilk f3ctors innuellccd hy gcotcchnic31 conditio ns. con ~truct i o n material costs, and ,tructUl'C loads. TIle drilled shaft and anchor bolt. dircct-cmbedded pole. and embedded casing foundations arc the Inos! eOIllmontypes u!;ed for tubular ~ teer pole structure:.. Guy attachment and anchor locations arc usually determined by structuralliupport . electrical dcaram'e, and right-of-way considerations. C4.S.3 Climbing lind Maintenance I~ro\' isions Gcncl1llly, provisions should be made so thtH all pol1ions of structures, and insu lator and hardware a~scmblics. arc !lccc)'"iblc fur mainlcn:mee ptll'j>oses. Where ~ tep~ and/or laddet); arc requ lI'Cd, they should be sufficiently strong so they do nOl dcfonn permanently under the weight of maintenance person nel with tools and equipment. All cli mbing devices should be oriemed to Pfl>vide adequate clearance between maintenance personnel and encrgil.cd part~. allow ing for conductnt' movement under specified climatic condition". Detachable ladders should be faurica tcd in lengths that can be handled by maintenance perwnnd on the structure. Additional information o n climbing can be obtained in IEEE'" Standard 1307. " IEEE Stand:ml for Fall Protection for Utility Work,"

CS.O DESIGN OF I\ JEMnERS CS. I INTRODUCI'I ON Thc American In ~litllte of Steel Con ~t ru t't ion (A 1SC) and. to a lesser extent, the American Iron and Steel III',titule (A ISI) SpecificatIOn" IC5- 11. {C5+21 are the basis for the desi!!" requIrements of this standard. Trdn\mission s truc tu re~ have traditionally !>cen dC~lgned based on ultimate ~ Irc n gth method .. using factored loads. TIle design "Ire s~es of thi ~ standard arc derived from the American Institute of Steel Conqrut'tion Allowable Stress Design SI)CCification. 9th Edition. AISC allowable stresses afC applicable 10 equations where the m{'mbcr force.s are the resu h of unfactorcd loads. TIle design ~tfl!S~ val ues in Ihis ~ec­ tion arc based on the altowllble stresses in the AISC specification. with the vulucs 3djusted upwurd (by factur~ rangi ng from 1.5 to 2.0) for UM! in ultimate

24

~tre n gth design and to compensate for the equiv:! lent "afety factors built into the AISC va lues. These design I'cllu irctllent~ arc :!pplicablc o nly to tubular members, tlll S~ members, and guys. For design of {It her members. the USCI' should refer to ASCE Standard 10 IC5-3J or In the A ISC Specification [C5- 1J. wi th appropriate cOIl\'crsiollS fro m all('lwablc stress to ultimate strength design. The AISC has published design criteria IC5.4 1 based on the Load and Rc~ i sta nce Fat'tor Dc~ign (LRFD) methodology, Additional test ing to determine prob!lbility·bascd factors for details unique to tubular transmission structures is requ ired prior to adopting the LRFD method .

CS.2 MEMBERS The f('lrmulae uSt."tI in thi~ sect ion hbtorically have been used in the industry In de~ig n member.; with cross-sectional shapes shown in Appendix II and members with elli ptical or rectangular cross sections thill have ma)\imulll major to minor d illle n ~ion ratio~ (lf 2w l .

CS.2. 1 Materials CS.l. J. I Spet'ijiCfllio/a' Steel pole ~ lJucture~ nrc typically manufactured from high-strength structural ~tecl with a yield slrength 01'65 hi (448 MPa). 'nle SUllable tnate ri al~ listed include some that lire not specifically referenced in the AISC (lr AIS I sJX"ci fi e:l li o" ~, but have been pr(lven ncceptable through in-~crvicc perform:mce. C5,2. I ,1 Material Properties Cold working in forming tube:. in<:reilse~ the yield stre:.s of the stcel. However. mcre:lslllg the design yield stress ovcr the minllllltnl yicld Slress spec ified in the applicable ASTM lipeeifil'atlon is not recOIllmended. Since the difference between the yield litrc~s W,) and the tensile !.Ires,> (FJ of the high-strength ~tecls fro m which these slnlctures arc nonnally f:lbTleated i ~ rel:!tively ~ tnall , the he nelicial eITect of cold working would also be relatively slIln l!. Furthermore, this benefi t would like ly be offset to some extent by n redu('lion in the notch lOughne~s. C5.2. /.3 Ellerg)'- lmp(U:ll'roperlie~' Genel1llly, brillie fracture can occu r in Slnlctural steel when there is a sufliciently adverse combi nation of tensile Slres~. temperature. Slmin mle. and geometri+

ASCflSEI 4S·0S cal discontinuities (notches). Other design and fabrication factors may also ha\c Iln imponant innucnce. Becausc of the intCIl-clation of these effects, the exact combi nution of )otre)'s, temperature, ~t rain rate, nnlchcs, anu other conditions th;11 will c:tuse brillie fra cture in a g.iven ~t ru Chlre C:lIlnot be re3dily calculated . Consequently, designing again..,t brittle fr3clure primllrily involves proper steel selection and minimizing geometric discontinuities. The impact requirementl; or thi' section arc based on historical expcricno.:c of "tructurc pcrfonmmcc. 111esc requirements exceed those listed in Table 3. 1 of ASCE Manual No. 72IC5-51 forcenain platc l;trengths and Ihickncl;sc)" but the added cost of providing this testing is minimCd. The requirement contained in ASCE Manual No. 721C5-5 1 for plilte testing of controlled rolled 0 1' as-rulled platt's over 0.5 in. (13 mm) in thickness wa~ elimi nated bJSI,.>(1 o n e)l;pel'icnce wi th the plate quality eurrerltly produced by steel m:mufllcturcrs. CS.2.2 l clIsion Fur tension members with h ole~ or slots, yielding of the net are:1 m:ly bct'OIll(: a senic(:ability limit ~tale warranti ng speci"l con~ idcr.tt ion and e.\crci~ of englneeringJudgmcnt. The~e conditions can result when Ihe length of the hole or slot along the longitudin:ll "xi~ of the member e)l;~L-etI$ the member depth or con... \IlulCl> an appre(-'iablc ponioll of the member length.

member. Theoretically, K - 1.0 for a member pinned at both ends IC5- IJ . In practice, these members are attached to the stmclure with a si ngle boh installed I>crpcndicular 10 the plane of the tru~s member. This {.;Qnllcclion may nOI al't ;IS :\ pin 1'01' 10:lds out-of-plane with the member (~uch as longitultillal or lon;ional 100Ids on an II-J'rame ~ tru cturcJ. Thi<; is especially imp0l1ant in the de~ign of nonsymmetricalmemben;, such as angle... Engineering judgment shou ld be used in the selection of the K factor for this type of eonnL"Ction. Truss members u<;ed for cross bracing 3rc u~ually connected at the poim of inten.cction by means of a U-bolt or through bolt. This ~'ol lll ec tion dlanges the effective length of the compre ~~iQ n brace. based on the amount of rotation:11 SUppOl't prov ided by the ('011neClion. The effective k!ngth ror tubul3r members h :l~ been shown to be dependent upon the relativc load le ...cls between the compression brace and the tensiOIl bl';lce IC5-61, IC5-71. Assuming no rotational suppon i" provided by the bolt and the point of IIItc~ct iol\ i.., at the midpoint of the eros .. bracing. the K ractor varies from 0.5 (t e n ~jon load = 60% to lUO% of the compression load) to (J.n (no ten .. ion). This K fanor applies 10 the 0\ el':.I1I length (If the compression member. Ref. [C5-61 provides suggested K fal:tors ror other bracing configurations. If the connct,tion between the braces provides sul1icient rotational su pport, K = 0.8, based {1Il the length or the comprc)'sion member from Ihe intersection of the braces to the main suppon

leS· I I. KL/r values for tub... I:lr tru'iS members should be limited to prcvent potemial vibrat ion problems. Typically. these member:. are limited to value\ of 200 for compression members und )00 for ten~lon members IC5-ll.

CS.2.J Compressioll CS.2 . .1. ll'r/lSS Mell/ben'

CS.2.3.2

Ilelllll

Memb/!r,\'

A~ diso.:u~~d in SectIOn C4.4. L the clastic stabil ity of beam elements in tubular structu res is numerically checked during the nonlinear analysis and need not be checked by manu:,] methods. However. when nonline:lr analysis methods are used, the stability of tru"s clements. which by defi nition can C3ITY only a"ialloads. is nOI checked. T he"" members rnu ~ t be IIwnualty checked for stnbi lit y using &15. 5.2-3 and

This sect ion determines Ihe de~ign compn::s)oive ~tress ba~cd on what is commonly referred to a" local buckling. When IC!'ling j, performed 10 detennine loc!!1 budling stabi lity, actual yield ~ trengths and dimensions of the tcst ~I>cci lll c n ~ should be used in the calculations.

5.2-4.

through 5.2- 14 lire based on rC
Typically. truss members, made from round or ptllygonallubes or angles,
C5.2.1.2.1 RegulaI' Polygo//al Mcmbcr.\· EelS. 5.2-6

DESIGN OF STEEL TRANSM ISSION POLE STRUCTUR ES Ba~cd on this testing. less con<;crv:llivc criteria than were previously used have been est:lblished for polygonal tubes with eight or fewer sides (Eqs. 5.2-6, 5."2-7. and 5.2-8). However. these C(llIations should be

Thus, dinerenl equations are provided for octagonal. dodecagonal, and hexdccagonaltubcs. These equations arc su mmarized graphic:ll ly in Figs. C5-1. C5-2. C5-3. and C5-4 .

•••

T.. A..B. CrIoon«l Co.

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f iGU RE C5·1. Local Iluckling Test Data fo r Octagunal "nlbes.

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FIGU RE CS·2. Local Buckling Tcst Data for Ilodecllgonal Tu bes. 26

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.., ,I,;' !., FI GURE C5-3. IAK"lll Ducklillg Test Olila for Hexdecagolllll 1\lbcs.

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fi GU RE CS-4. Compa rison of Loe:ll Bu ckling Equalions.

used only when the primary loading is bending. II' Ihe u:
(200 OPa) and a plate buckling cocfliciell1 or 4.0. The use of polygonal shapes in these ranges of w/t;1' uncommOIl.

C5.2.3.2A R()uIIlI Members &1. 5.2-17 is [he Planterna fomllll
DESIGN OF STI::EL TRANSMISSION POLF. STRUCTURES

(200 G lln). Fig. C5-5 ["Ref. C5· 12j shows ilto be a good lower bound 011 the Icst rc!'ults of axially com-

Fig. C5-6 and provides ;I good lower bound. The tests shown herein arc fro m Refs. [C5-ll] and

prc.<;sed mnnufaewrcd round IUbc~ . Manufactured tubes art! cla')\iried a~ tube~ producL-d by picf'<:lIIg. forming and welding, cupping, extruding, or other method.;; in a facility devoted

res-In The II),C of circular lubes with I)Jt values exceeding the upper limit" c.'tablishcd by Eqs. 5.2-17 and 5.2-19 is uncommon. and no :llIow:lble siress equmion<; arc provided for them. To eSlablish such cquntions. an ;ldequalc Icst progr;lI11 would be needed .

specifically to thc production of tubes. Eq. 5.2- 19 is;\ modification oftilc P):mtcJlla formula derived from thc test results shown in

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FIGURE CS-S. Local Uuckling Tcst Oal:l for Round Tubes in Compn·.!osion .

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FIGURE C5-6. Loclil Buckling lest Oala for Round 'lilbes in Ucnding.

ASCEISEI 48-05 CS.2.4 Sheur Eq. 5.2-20 i" a rounded va lue of the yield sl ress in shear rF,/V31 based on the di "tort ion-energy criterion.

replaced after the occurrence of such an c"ent to prevent excessive structure dcnectio n ~ or .~ trc sses as a result of the ine l a~tic ;,trctching of the guys.

CS.2.S Bcnding A reduction in tht: de!>ign l'Ire!>!o to accoulll for lateral-torsional budding is not nccesSilry for ILLbular members becausc of thcir superior torsional st iffne!,!>. F. is based on local buckling only since stabilit y Will ha ... e been verified by nonline:lr al1:1 I)'sis.

REFERENCES

CS.2.ti Combined

Stresse~

COmblllatio ll~

I)f shear stresses and normal st resses have been eval uated by the distortion-energy (llcncky-M i'>Cs) yield criterion. More I,.'onservatlve critelia may be used. Stressc..s ~houl d be properly COI11billed :11 a gi\;en point on the cross section. They are not ncccss:lJily the addition of tlie maKimum stresses. For example. the maximum nonnal stress o<.'curs III an extreme fiber. while the Ill:lXi mUIll ... hear slress occu r~ :11 the neulral a.\ is. Normally. the highest "treSs result s from t'ombllling the maximum normal stress with the she:!r stre;,s oceumng at the ,amc point.

CS.3 GUYS CS.3. 1 Mutcria l Properties Zinc cQteel str,lIld per ASTM 8416 are commonly used for guys. Capadties of the!>e ~tr.l nd s arc stated as the minimum rated brenking ~trcngth. Physical propcnies. sueh as minimum rated breaking. strength and modulus of elasticity, for othcr types of wire strunds or ropc~ should be ~pec ifi ed by the Owner. CS.3.2 TensiOIl The level of fon.-e represented by 65% or the mted brcnking strength of a guy is a rC;lsonable mcasure of the point at which the dcfmmation rate begi ns to become nonline.. r. Thh; is annlogous Wlhe yield ,>trength of other ,teel members. Forces greater than 65% or the rated breakmg strength of a guy have been permitted (NESC)_ Ilowcver, when stres~ed nbove 65% of the r.lted brc:lkIIlg strength. inelastic stretching or the guys may ()(.'cur, which is outside the scope of this standard. For further inrormation St.'C Chapter 6 of ·'Design of Guyed Elcctrical Tl1Insmis!o.ion Structul\!S:' IC5-13J. Additionall y. the guys !o.hould be reten!o.ioned or

rC5- 1J America n Inslitute o f Steel Construction. ( 1989). SIH!cijicolirlll for S'n/cturlll Sleel 8I1ildillg.~. Chicago, IL. JC5-2J Americ!> ~ecli{l n s in bending:· p;lpcr prcsenleJ m ASCE Nmional Water Resource, Meeting, Los Angeles. CA. JC5-IOI Plantcllln, F. J. (1946). '·Collapsi ng Slressc~ of d1\;ular cyli nders and round tubes,'· Report No. S.280. NUl, Luchlvaanlllbatiori ulll . Amslerd;lIn, The Netherlands. IC5- IIJ Schi lling.. C. C. ( 1965). ··Buckling strcngth or cireular tubes:· JOIII"I/al of Ihe Strucwrflf DiI'isioll. Vol. 9 1. No. ST5, PnK·. Papcr 4520, pp. 325-348. ASCE, Reswn, VA. Le5- 12] ·'Te<;ts o n rou nd tu bes in bending:· Union Metal Manufacturing Comp.. ny, Canton, OH, unpublished intcmal report.

DESIGN 0 1· STEEL TRANSM ISS ION POLE STRUCTURES

rC5-131 Arnencun Society of Civil Engineers. (1997). " Design of Guyed Electrical Transmission Structures," ASC£ Mamwl.f (II/(I Rl'I'0rl~ on EnKilJ('~""1( Praclict, No. 91. Ne .... York. NY.

C6.0 DES IGN OF CONNECTIONS

C6.1 INTRO DUCTION Tr.l1lsmission .s tructur~ haye traditionally been designed baSt.'(\ on ultimate strength mcthods using factored loads. The design ",lres",es of Ihi s ~pccirie:l­ ILOII arc deri ved from the American Institute of Sleel Con~lmction Allowable Stress Design Spccilic:ltion. 9th Edition. A ISC allowublc ~t rcsses arc applicable to Clluations whcre the member forces arc the resultant of unfactored loads. The design ~trcss vu\ues in thi.s section are based 011 the allowable stresses in Ihe AISC spccilie~lI i o Ll . with the val ues adjusted upww'u (by factors rangill!,! from 1. 5 to 2.0) for usc in ultimate strength design and to compensate for thc equivalellt ~:lfcIY factors bUilt 11110 the A ISC ,,:llues.

C6.2 UOI; nm ANI) IllNNEI) CONNECTIONS Bolted Cllllllcclions for stecllran~l11l",s ion pole structures arc normally designed as shear. slip-critical, or tension type connections. Pinlll!d conllc(:tions are ones in which lhe attachments shuu ld hc free to rotate about at If:ast Olll! lIl(i~. whi le under IO:ld. The minimum end and cdge distances determined by the provi,ion" of lhis sect ion do nOI include ;ltlow;mcc!> for fabri,alion IOlel'lmces. Typical anchor bolt holes in base plates are 0.375-0.5 In. (10-13 mm) Mcrsiled. C6.2. I Materials Commonl y used fastener spccllication<; (nr sti,.ocl tran~mi~sit)n 1'IOle S1n1ctures arc A325, A354. AJ94. A449. and A490 for bolts. and A563 for nllts.

C6.2.2 S hl'aI' Stress in Hcuring Connections An :Iverage shcur stress at failure for A325 and A490 bol", i~ 65% of the specified minimum tensile ~tress of the bolt. The appro"imatc level al which the defommtillll rate begins to incre:l5C signiricuntly is

)0

70% of the avemgc shear strc~s. Thus. the vulue of OA5F. rc.;ults from (70%)(65%)F•. C6.2.3 Holts Subjed to Tens ion The spC'ciried tensile stress OIpproximatcs the point at which the nlle of elongatit)n of the bolt begins to significantl y increase. The ASTM proof-load stress is approximately C(llia l to the yield slrc.;s. Whcrl! a proof· load or yield stress is not specified. O.60F. provides u conservative estimate. Pcnmment elongation will occur in bolts if design stress c'(t'ced~ the yield s tress. This could cause the nuts to loosen OInd aO'l!ct the integrity of the joint. C6.2.6 Minimum Edge. OisllUl l'CS lIIul Dutt Spaci ng for Dolt cd COllnct:tiol1s The provisions of this section are apptic:able to sheared and mcch'lIlically guided n:llne cut edges. The first equation (6.2-6) provides the edge distance required for s trcngth. The required edge di ~ tal1 Ce is:L funct ion of the load being transferred by the bolt. the tensile strength of the connel'lcd part, and thc thickness or the connected pan. Test d ata conri rm that relating the ratio of end distanCI! to bolt diameter to the ratio of bearing stress to t en~ ll c strength gives a lower bound to the published test data for sing le fastener connections with stlmdllrd holes IC6-II . The edge distance required by thc above e ... prcssion h:l., been multiplied by 1.2 to accou nt for uncertainties III the edge di.,tance strength of the mC'mbcrs (Kula!.. et al. 1987). For adequately spaced multiple bolt connections. thiS expression i~ co n ~crvative. The second equation (6.2-7) is a lower bound on edge dbtancc that has been SUt·cc:-.:-.full y uscd in pmctice in stre~scd members. Lmitude is provided to U~I! the minimum edgc distances and to dClCmline the allowable bearing stress for this condition. llH.: first and second equulions (6.2-6 and 6.:!-7) determ ine which combi nation of bcllring value and ellge di~ t ance ~atisries the engi. nee ring :1111.1 detOlili ng requirement ... The third equation (6.2·8) places an edgc dist:mel! re,l riction o n thick membeN ~uch thai punching the holes docs nol create a possible breakout condition. If the holes are drilled in rncmbeN where lhe cdge distance would be governed by the third equation (6.2-8), this requirement h. not neccssary. Sat isfactory punching of the hok" in thick material is dependent nn the duct ility of the steel. the adequacy of the equipme nt (cap:lbility of the punching equipment and prol>cr maintenance of punches and dIes). the ullO\\ed tolemnce between

ASCEISEI 48·05 the punch and die, and the tcmperature of the '1h..'cl. The fnllowing guidelines h:we been sal isl'OIclOrily u~ed: For 361..si (24/j MPn) yield .,teel. the thickness of the mntcriul should 110t exceed the hole diameter: For 50 ksi (345 MP:I) yield steel. the thickness of the materi:LI should nOl exceed the hole di
C6.2.7 Hearing Stress in Pinned Connections Single bolt frilm ing connection" and insulator or !luy slmck le attachment .. arc considered to Ix> pitln1..>O connections. The design stress is less than that for bolted conncction~ to account for the rotatIon that is lypical of a pinncd-type connect ton. C6.2.8 Minimum Edgc Distullces for I'inned COnnectiolis The first equation (6.2- 12) provides a check for tension "CfOSS the net )'ection, PCIlx:ndicu lar to the load. The second equiltion (6.2- 13) provides a check for ~hcar (tcarout). with ,he:lr pl:llle:. developing at each '1 ide of the pin through the end of the member. llere the ratio of the d iameter of the hole to the dIameter of (he pin rnu<;( be less th:lII 2. This ratio represents the range of experience over which the equation (6.2-13) has been u!>Cd in pr:lctlce. Oversi/.cd holes arc commonly 1IS1..'(i a~ load altal'hml'nt points for insul!l\or ~ trings, overhend ground wi res. lind guys. Thcse ho les nrc not used where C(l nnel'lio n ~ are des igned ro r load reversal. Factored design IO:Jds sl1(luld be u~d with Eqs. 6.2-11 ,6.2- 12, :md 6.2-13 of Sections 6.2.7 and 6.2.8. These recomtllcnd:nions do nm excl ude the u~e o f othcr attachment holes or slots designed by rational :Inalysis. No adJu~t­ ment 10 the equations is rCtJulI"Cd for slight chamfering of the holes. For attachment plate), subject 10 bending,

addItional a n:ll ysi~ i~ requi red to determine the plate lhicl..ness. To avoid indent:ltlon and cXl'cs~ive wem of the material under everyd:JY loading. lhe following ~ hould be met: P s 0.5 (III::'

CEq. C6.2-1)

where force tr.l n ~ m itted by the pm: nominal diameter or the pin: lIlember thickness: and F.. ""' ~peeilied mitHlIlum te n ~ilc stress of the member. p

(/

Everyday loading Cilll be deli net! liS the ~ u s~ai n ed 1001d ing rcsuhing from the bare wire weight at 6O"F ( 16"C) fin al sag. Ir the loc:ltion is ~lLbjec ( tl) steildy prev3iling wind, the e\l'ryday loading c:m be considered 10 be the resu hant load eilused by the hare wire weight and the prevailing wind at 60°F ( 16"C) fin:11 sag.

C6.3 WELDED CONNltC'rIO NS C6.3.3 Oesign Stressl'S The design '.tre~ses in T.lb1c... 6.3. 6.4. 6.5. and 6.6 for welds are those of the AISC Allowilble S tress Design Specification. 9th Edition. multiplie d by 1.67. Punching shear s trc s~ should be considered in connection designs. C6.3.3. / TI,rollgl,- Thicklles.~ SlrcSof Thi" res trk~ ti o n is applicable to plates welded perpendicular to or nellr lx:rpcndicul:Lr to the longitudinal axi .. of member.> (e.g .. ba~eplute~, n:tn£e pi ates. >lrm bracket. etc.) 3nd takes into con~i d ("""J tlon the possihle dC'iiciencics in the tcn~ile strength through the thicl..II CS~ of the plates. which may rc)'u lt in lamellar tearing. Ulnlcllur te
CftA FIELI) CONNECTIONS OF MEl\IIlERS

C6.4. 1 Slip JoinL.., Fabrication and erection tt)ler:mces sho uld be included when establi.,hing lap length requirement ... Experience ha:. shown that an (l\'crlap or I A2 to

31

DESIGN OF Sn.EL TRANSMISSION POLE STRUcrURES

1.52 time~ the maXHnUIIl m~lde diametcr (across nmsJ of the outer section j" "uffieicnt to dcvclop the re(jllll'Cd fotrcngth of the connectcd 12-sidcd polygonal ~eclions, pll)vided there arc no significant gaps bclw~en the mating section" lind the manufacturer's rccollullcndcd assembly force has been used, Maximum lap should he restrictcd by practical f:\C10 .... ~uch as m:lim:lining thc minimum height of the assembled :;lruclure, minimum clearances between crOSSilrms, interference with climbing devices, elc. For frame ~tructures where leg-length tolerances :'lre critical, the structure designer mily consider u"ing bolted nange connections as a ~ub!o.ti lut e for slip joinls,

C6.4,2 !lase and Flange Illa1c Connections Theon::lical melhod~ of 1l1ll11ysi!> for ba"e plme design have not been publi~hcd, It is recommended tlml details and prnctices provcn through testing be used. Appendix V I provides a pruposed method 10 dCh!rnline the plait' thicklle~<: rOr:l base plale suppon..:d by anchor bolls with le\-eling nuts. In eenain types of structures (e.g., guyed poles or r,..un..: \Iructures), the culcuhued design loads may be ~Ignll;can tl y 1cs~ th:1II the loa(l capacity (If the ItIbulur member al Ihe base platc or nangc joint. It is not t"OIlsiden::d good engineering pntetice to sit,c the base 01' Oange plate eonnel;tion for loads "ignific:lIltly lo",er Ih,1I1 the lube c:lplldty. Thus 50% of tube l'apacity has been est;tbli\hed as a minimum strength requircmelll for ~uch wclded joint eonnectiom;.

C6,S TEST VE RIFI CATI ON

llleorctical method<: of analysi:> for aflll cO llncctiOIl~ have not been published It I~ recommendcd tilat detail" and pructice~ proven through testi ng be used.

the Ow ncr provides shop delail drawing<; as pan ofthc contract documents, and their correctncss is the rc~po n sibility of the Owner. DilTcrcnccs bctwCi;:n the Owner\ drawing requiremcnts and the Fabricator's shop praclices ne..:d 10 be resolved prior to commenccment of fabri cation,

C7, I.2 Drawing Rc\'icw The Structure Dc~igner's revicw of drawin1,!:; includes rc:.ponsibility for the ~Irength of mcmbers and eonnc(1ions. llle coO'cctncs\ of dimen~ional det3d ca1cul31ions is the rcspon~lbility of the Fabricator. Re,iew of drnwings docs 1101 include appl'Ov31 of mean:.. metilo
le6-11 Kulak, G, L., Fi\il..:r, J. W, ,and Struik. J. II. A. ( 1987). Guidt' 10 Iksign Criteria for /Jolted alltl Ril'l!ll'l/ JO;lIll', 2nd cd .. John Wiley & S(ln<;, New York,

C7.0

OETAn~ I NG

AND FABRICATION

C7. 1 DETAILING C7. 1.1 Drawings The de~ign or :;tecl tr.II1~l1liS!>ion poles, indudll11,! the prepamtion of :;hop detail :!nd erection dmwings, i~ typit'ally performed by the F:lbricator. Occasionally.

Clearance and appearance rcquirelllcnt~ arc normally established by the Owner. while str<:ngth an" as'>Clllbly rc(luiremenb arc e~t:.lblished by lhe Structure Designer, Foundation type, stnlcture d ..:~ign, and con~truction method:; ure fuctol'<: lhat should be considered when establishing IOlcr.lIlce~, Thc Owner should coordi nate dimcnsioning of Ill:lting pail S obta ined from diffe relll ~o u rces, Thc Structure Designcr 01' the Owner <;hould either imposl' wlcrances thai wi ll en,ure ea~e of as"ernbly or require pn::a~<;Clllbly and match marking of mating part~ by the Fabric:llor. The Structure Designer <:hould estabh~h IOlcr.lI1ces to cOlllrol cri[ical cro~:o.-~cction propcrtlel> and to cOnlrolthc magnitude of the internal rc:tclion" For example. a maximum vari:l1ion of -5% for "cction mooulu" i~ recommcnded This is within

ASCEiSEI 4g·05

tolerance... SCt for stamlard structural by the ASTM A6 s;pccific:LtlOn.

mentbcr~

cO\'l!rcd

C7. 1.4.4 CQrrosion al/{//'j'nisll CtnlSit!eraliQlIS Surlilce preIXlr..Ilion ~ hould reference a Steel Structures Paiming Cou nci l (SS PC) speci lic<1tion when possible. Dmwings <:hould <,how painting requiremcnts lIIc1uding Ihc paint systcm, surface preparation, mill'O\er.tge. number of Co.-II!>. :lIId color. i»li nt 1ll1lllUfacwrcr's application recommendation, ~hou ld be available. GalvaniLmg. should rdercm:e the applieaDle ASTM sjX.'dficmion. ASTM A 123 is typically referenced for pl:1Ie)' and shapes. ASTM A 153 is referenced for hard· wllre. Venting :md draining details should be indie:ltcd. Mct
I. "Drilled-hote" for holes spI.:cilied as drilled alld lIot punched; 2. " HOI-bend" \.\hen forming i~ to be done hot and not cold: and 3. "Acceptable wctding processes" \00 hen one or more processes are unacceptable.

C7.2 FAHRICATION C7.2.1 M:llerial A wide variety of stcels arc used for steel pole '>tructures. This requi res the Fabricator to carefull y malm:!in the material identity throughout fabrication . C7.2.21\lalcriall'rcpar:.tlion Material preparation includes Culling. bending, and machining. T his ~tiuld:lrd delines the performance requirement ... but doc)' nm spec ify the l1le thod ~ to be u~ed III accomplish these operations. C7.2.2. 1 CUlli"g CUlling includes 0l>crat io n\ 'lleh as shearing, torch cuui ng. and sawing. Materialthlll is to have stl".light edges can be CUI \0 si/e with a shear; however. care must be taken to prevent cracks or other defcets from forming at thc ~ hen red edge. Limi tations of scc-

Iron .. iLe and length of Ihe ~hca r must be considered to e n ~ u rc a good cuI. Ally curved or Sll1lighl edge call be c ut wilh :I buming torch. Care must be takcn to pre"ent e rack~ or ot her notch defects from form ing al the prcpared edge. and all slag must be removed. Where"er practical , the torch should be mcehanically guided . Edges prepared for welding or subject to high stresses shou ld be free from sharp notches. Recntmnt cuts should be rounded . Edges cut with a handheld torc h may require grinding or other edge preparation to remove sharp notches. Steel ca n be cut wi th a rcciproc:ltmg band saw-type blade, circ ular ~ t on e saw. or friction <;aw. C7.2.2.2 Formi,,/{ Braking. rolling, stretch bcndi ng, or thermal bendi ng (cambering) arc fo rming processe~. Tubes of various cros)' scct i o n ~... s well a~ open ~ ha pcs (cli ps and brackets. for example), can be produ('ed by braking. Ro ll forming is normally u-.cd for circular cross sect ion),. In roll fonning. the plate is either formed aro und an internal mandrel or rolled by forcin g with cxtcnHlI roll~, Either CO n~l i1Jlt eros'i-scct ion or tapered tubes can De made IhlS way. Tu bes of various cross sections and tapers ca n be made by pressi ng plates in specifically profiled punch and die sets. Completed straight or lilpered tubes c:m :11"'0 be pressed LIllO a die -;ct to fonn curved crossanos;. Member; nlCfillUrc of the lIletnl. SCpal'lllio li of lhe steel ca ll occur during rorming because of thl' method used. radii and temperature. amI/or imperfections in thc material. Hot bending wi ll allow ),tllatter bend mdii to be mcd than cold bending. Improper lemper-lime during be nding C,In adversely lIn'eet the material. Proper tCIllper.llures can be obtai ned frum the 'iteel producer. testing. or various AISC publications. 3.1

DESIGN OF STEEL TRANSMISSION POLE STRUCTURES

C7.2.2.J I-Iole~' Typicully holes may be punched in stt::el when the relmionship between the muterial thickness und the hole diameter meets the recommendations of C6.2.6. If the steel is to be galvanized. precautions ag

C7.2.2.-I ldelllificutjoll Piece murks nrc typically at least 0.50 in. (13 mm) in heigh!. They are genemlly made either by stamping or by a wcld deposit. prior to any finish application. C7.2.3 Wdding Welding may be performed using m,HlY diOcrcnt processe", and procedures, but should be in con form
stand the swtic design loads specified for th:1l struCture as an individual entity under controlled conditions. Proof tests providc insight into ,Ictunl SlrC~S distribution of unique configurJtions. tit-up verific:Ltion, perforrmmec of thc structure in :L denected position, Clnd other benefits, 11le test cannot confi rm how the st ructure will react in the transmission line where the load~ may be more dynamic, the foundations may be les<; than ideal, and there is some rcstrllint from int;Jct wi res

the loading. deflection. clearance, and other design specificat i on~ set forth in the cont ruct. The Structure Designer should npprove the proposed procedure for prOtotype testing. Also, the Structure Dcsigner or designated representative shou ld be present lit all times during the testing sequence nnd lIpprove each decision mnde dtlling the process. The Owner should review the testing alTangeme.nt I'm COI11pliance with the contract document!> and the intent of the test. The number, location, di rection, holding time, sequence, and increment!> o f the test load~ and the number. location. lind dinxtion of del1ection readings :..hould be specified by the Owner. The mClhod of alla!.;hing the test 10;lds 10 the pl'Ototypc, applying the test loads, 1l1ea~uring and recording the lest loads, locations
C8.0 TESTING CS.2 FOUN DATIONS

CM. I INTRODUCTION In OJ trudition
The type, rigidity, strength, and moment reactions of the ,K·tual allachlllent~ of a prototype to a test bed may affect the ability of thc mcmber:.. 10 resist the applied loads. Therefore, the restrnim condilil' lls of the test foundntion should be as close as possible to the eX]JCctt::d design conditions. Pole structures that arc dc~ig l1cd to be lIuached to fOl1ndation~ through .. ndol' bolts should be tested (111

ASCElSEI 48,05

all anchor bolt arr:mgemellt attached to the tc.st facility foundation in a manner that wi ll best ~j rnul ate the design conditions. leveling nut~. if used. should be sct
It m:ly be desi rable to specify dctailed methods or sequences for erecting the prototype 10 prove the al'ceptability of lhe propo!>Cd lie ld erect ion Illt"thad. Pick-up points designed into the structu re should be used as part of Ihe test procedure. After the prototype has been assembled. erected. and rigged ror lesting. the OWller should 1'C\ iew the test ing arrangement for cOl1lpli,mcc with tht" contract ducuments. Safety guys or olher sarety features may be loosely attached 10 the prototype. 1lley al'C used to minimize conSe(luentia l damage 10 Ihe prototype or to the testi ng equipment in Ihe e ... ent or a failure. t!~pc­ dally if a ICSHo ..destl'Uclinn '" ~pcci iied. Load effects of the ..afely guys \hould be 1I1111imi/'ed during the te~t.

Cg.J MATERIA L

C8.7 TEST LOADS

All prototype material should {'onfotln to the minimum fcquireme nt ~ o f the m'lIeri:!.1 spccilied in the design. Bec:IU"e of the allOying method~ and ro lling prJcticc" used by the ,teel mills, all sted plates have yield strength variatiom. Although desil"llble. it is impractical to limit the maximum yield strengths of the materials used for the fabriC;ltion of a prototype. Test loads should not be increased a~ a me:ms of accouming for material yield strengths that arc in excess of the specified minimum \alues.

Destruction is deli ned as the inability of the prototype to with~l:l nd the application or additional load. The deslntC\lon case .. hould have u ma1tHllLlIll percent over· load establ ished prior to testing.

C8,4 fAIJIUCATION Normally, the finish is not OlPl)lied to the prototype ror the test unless specified by the Owner. Nonslrueltlral hardware allaehmenb such as laddcrs, step bolts, etc .. are not norm.. lIy inst:Jl1ed on the prototype.

CM.S STRAIN MEASUI:f.EMENTS Sl re~s dctenninUlion Ill ethod~. primarily strJin gaging, mlly be u~ed to monitor the loads in ind ividual melllber; dunng testing. Comparison of the measured umt 'tre~' is useful ,n \'ahdating the proof test :md relining analysis methods. Care must be exercised when 1Il~lnllnenting with ~tr:lin gugcs. a~ 10 both

local ion and number, to ensure valid correlation wi th design stress levels.

CS.6 ASSEMBLY AND ERECTION

CHJ~

LOADAllPLICATION

V-type insulator strings 'Should be I"albl at the l)(Jint where the insulator strings illlef"S\!ct. If the ill~ulators for the structures in service arc 10 be a style Ihat will not support cornpres~io n . it i:-. ret:omme nded that wire rope be used for simul ated H1 .. ulator~ in the test. If strut or post insulator" arc planned for the structures. members that will simulate the in .. ulators should be lI~cd.

A~ the prototype denect.!> under load. load lines may change their direction of pull. Adjustments should he mude in the applied loads so th<11 the vertical, transverse, and longitudinal vectors at the load points in the dcllccted ~ hape :U'C the loads specified in the loading sche(lulc.

C8,9 LOADiNG PRO CE DURE It is customary that IO<1d l'a\Cs Ita\ iug the Icast innucnce o n th,· rc.su lt s of successive tc:.\S be tested lirst.

DI:SIGN 0 .. STEEL TRANSM ISSION POLE STRUCTURES

Another consider.lIion should be to ~implify thc opcrn· tiOll~ nccess:'lry to carry out the test program. Normally 10:lds nrc appllcd to SO%. 75%. 90%. and 100% of the factored design louds. The 100% load for each load cuse shou ld be held for 5 minutes. Unloading should be cOl1lrolted to :lvoid possible damage or overload to the prototype. Lo:lds should be reduced to a minimum level bet .....een load C:I!)C!> except for noncritical load case!> whcre. with the StruclUre Designer's approval. the load) may be adjustcd as required for the next 10..1d ca~c.

C8. tJ POSTIEST INSPEC riO N The Owncr should indicate .my special inspection fC(]u iremCnb in the contmcl documents.

C8. 14 DISPOS ITION OF PROTOTYPE An undamaged prototype i, u~ull il y aCI,.'Cpted for UM: in the lransmis~ion linc aftcr 311 components are lIl~pcctcd in accordance with the test procedure anti arc found to be structurally ~(}und and wlthinthc t:1bri· cation toler:U1ecs.

CH. IO LOAD MEASUREMENT

CS. IS REPORT All applied load~ should be mcal>urcd as close to the point of :lIIachmcnt to the prototype as pmctical. The cffccts of pullcy friction ~holiid be minimi/.cd. Luud measurement by monlloring the load in a sin£le part of a Illultipart block and tackle should be ;Lvoided.

CH. lI DEFLECTIONS POIil" to be monitored should be selc-ctcd to \erify thc deOccliOI1'1 predicted by the dt'sign analysis. Also, it should be realizcd Ihat mealourcd and cal· cultlled dcnCClions might 110t agree. 11lere are two main rcason, for this. Fin-t. the calculations for deflec· tlons gencrally do not include the effect of denection :md di~tortion within the JOllltS and connections. Second. the actunl Sll\~~ses reached during testi ng often approach the yicld strength of the materi,,!. which, by definition, inl."lude .. some permanent sct in the ~tec l. Upon release of test load~ aftcr a cri licalleSt ea~e. :l protutype normllily will nOi return fully to its unde· !lected starting position.

C8.12 fAILURE-ii Thc prototype is normall y considt:rcd lIeceplUble if it is able 10 support the spccilicd loads with no ~lruc t uf:ll failure of prototype membeN or pans and has no visi· ble local deformation after unloading. If a retest is reqUired. failed members affected by consequcminl d,unuge should be replllccd. Thc load case Ihllt cau'\Cd the r:lilure should Ihen be repeated. After complction of tcsling. the prolotype should be dismnmled and inspectcd.

llie following inlonlliuion is typically included in the test report: I . The designation and description of the prototype tcs.ted. 2. The name of the Owncr. 3. The name of the person or org'lIli.wtion (Line Designer) that spc<:ificli the loadi ng. electrical cleaf:ll1ccs. technical requirements, and gcneral arrangement of the prototype. 4. 111e namt' of the SlructuI"C D~",i£ni.' r. 5. The name or (hc Fabric'llor. 6. A brief description nnd the location of the tcst facility. 7. The names 3nd DnilimiollJ; of the test witnessc~. 8. The dales of each te~t·luad cllse. 9. Design and detail dr.lwingl> of the proWtype. induding ally chungc" made duri ng Ihe tc,ting program. 10. A rigging diagram with {Iewils. of the allachment points to the prototype. II. Cal ibmtion record~ of the toad·mea$uring dcvit·e~. 12. A loading diagrnlll for eneh 10..1d case tested. 13. A tabulation of dencclions for each load ca,e testcd. 14. In case of failure: :I. PhotographS ofprototypc and all f:liled members. b. Loads:ll the time of f:lilu rc. c. A brief description uf the fail ure. d. The fCmcdial action .. t:lkcli. e. The mea.
ASCEISEI -lS-(JS

16. AIr tcmperature. wind speed and direction , Ilny precipitatioll. and an y other pertincnt metcorological data. 17. MillIe:.! reports :.ubnllHcd in accordancl! wilh Scction 8.J. 18. Foundation condition informatIOn. 19. Additional information speciried by the Owner.

(Fig. C9-3). Other types o f loundation~ ("prelld. pilc. rock andlor fo undatioll ~ . etc.) ma y be considered (or spcciric tl ppliCalio ns and "hould be designed according 10 an :lppropriutc cng ineering st:lndard.

I~S E

""

CY.l1 STRUCTURAL MEMUERS AN D CONNEC·

T IONS USED IN FOUNDATIONS

, . y/>:S .-»-. ...)'l....

"I-KIIH. ~'-'lr

,

"

~

CI). I I NTRODUCTION

" "

TIle lIIil!erial in Section 9.0 covc~ structural

rnernbc~ and

connections nonnally ~upplicd by Ihe stecl pole fabricator. NUIIlCI\)US fi.ICtor:-; enter into the selection of a foundation type, mcluding. but not limitcd to. the following: gcotedl1llcul con\ldcrmions: found ulion loadi ng: btlsc ~ilc of "tructure; rotation and dencction limitations: Ct;(JIIOlIlICS: :Jcslhclics; contractor cl(pcriencc; 3\'3i lablc equipmcnt: sile accessIbility; and environmental cOJlcl!m s. Many (hfi'erent foundation systems have been devclOpct.1lo mcct th,· va ricty of ~ tcc1 polc ~upport need,. 11m!c loulld:.llion types h,lYC becomc prcvalem :md :Ire addressed in this ~ tnndard: drilled shaft wilh :U1chor boh~ (Fig. C9-I); JirC(,;I-cmbeddcd found;! tlOll (Fig. C9-2); and e mbedded casing foundation

"

PlAT! T)

"1~lInIiM I

,, ,,

"

~--«~1,,, kI rr<. HIIU H)

(OWRfTl. r~llJ"'M.lIO'

;

FIGU R E CI)- 1. Dri lled S haft FUllnd:llioll with Ancho r Bolts.

IIH.. "l!1oi{, l'L\TE

£Ol CUlm CY-2. Direct-Embedded Poll'.

•

'~"" " ""

!lUnllM I_ ~ I 'I ( I II" ~:-;u ~Lll. I ~ I ~lin:-; \llll

BI. HLlU-, .... III '.-I;I)lIT

FIGU RE C9-3. Embedded C:lsi ng Foundation. 37

D~...sIGN

OF STI£L TRANSM ISSION POLE STRUCTURES

C9.2 GENERAL CONSIDERATIONS

C9,) ANCHO R DOers

In selecling Ihc type of foundation, the Owncr should the type of structun::, imporl
The drilled shaft i~ a type Hf foundation tl'l:lI is used eXlensively with anchor lxllt". The minimum rounda* tinn diorneter i~ determined by the di ll rnett'r of the boh circle, bolt diameter, and the necessary concrete clear cover. The minimum length of Ihe anchor bol .., should be determined by the StnlctUrc Designer in aceordallce with the number and ::.i7c of bolb used. Typical reinrurcing method.s include dcwlopmem-Icnglh urn:hor bolts plus reinforcing steel a, well as full-length anchor bolt cages, either with or without additional reinforcing steel. Dcpcndmg on Ihe gcote(:hn ical conditions ;mu the foundation IO'l d ~, the usc cof full-length ;mehor bulb clin proyidr: cost sav ings. Most dc.~ign cod e\ do not address the design or anchor bol ts and anchor bolt embedment. Typically thl.! Stnlcture Designer de~igns Ihe anchor bolt to resist the groundline forces. The Found.llion Engineer deSigns the foundation for the ~amc groundline forces plus any additional loads that would produce a maximum foundation bending moment. Threilded reinforcing bar is the most common type of anchor bolt u,c{1 for conncctrng s t eeltran~mi~­ sion pole structures 10 concretc foundation~. For threaded reinforcing bar, the anchor bolt material should be limitcd to ASTM A615, gr:Jde 60 for bars #5 through # 18 llnd gradc 75 ror bars # 11 through # 18 and # 18J (ASTM A6 15M, grade 400 for bar'l 10M-SSM ::tnd grade 50n for bar<: 35M-S5M).

~onsidcr

C9.J, 1 nolts Subjed InTension The 10:ld factUf(.s) ;Ipplied 10 the ::.tructure load". and the r:uio of (F./1-) will provide some additional fac tors of safety above thai complllcd by till.! eqllation_~.

C9.3.2 Shear Stress The ~hear is transmitted from Ihe boll 10 the concrete through the bearing of the boll al the: surface, forming a concrete .....edge approximately 1/4 of the bolt dimneler in depth. C9,J,) Co mbined S he:lr and Tension For steel tr;tnsrnis<;ion poles, anchor holts are bearing-type connection" tha! should include Ihrcad~ il11he she:lr plulle when sizi ng the bolt. The literature presents various equat ions ror approximl.lting the ~hem' ;1111.1 tension intcractlon. For the interaction equatIOn to be Yahd, the an~hor bolts should have no more Ihan 2 bolt dhuneters separating the bottom of the base plme and the top of the concretc. If the di.,tance is greater th:1II 2 bolt diameter", then bcndlllg in the bolt should be included when ~i/ing the anchor bolt.

A$CE/$EI 4S-05 C9.3.4 Ol'vclopmcnt Lcngth The # 18J (SSM) reinforcing bar meeting ASTM A615 gradc 75 (500) has been successfully used for anchor boils by the industry for many years. Until 1989. :mchor bolt embedment length c;lkulatiuns havt· been bnscd upon the ACI 318 devclopmentlength provision,~ for the dcfonned reinforcing bar. Revisions to AC I 3 18 in 1989. 1995, and 1999 tirSI increased and then decreased the development-length requirements. The commillcc decided to conti nue the industry practice of using the development-length provisions of AC t 3 18-83 for dctermining cmbcdl11em lcngth threaded. dcformcd reinforcing bars used as anchor bolls. The development-length calc ul a[ion~ ,Ire applicahie only to tlncoUlcd rei nforcing bars. Developmcnt length and unchoragc value calcu lations for headed anchor bolts arc shown in Appendix IV. C9.4 OJRECT-EMBEDDEO POLES Oin:ct-embeddcd poil! roundations utilil..e the bottom portion of the steel pole :l~ the foundation member re;lcting against the soil, rock, ;lndlor backl1l1. A direct·embedded polc foundation typically is designcd to transfer overturning moments to the in silll ~oil. rock. or bad-nil by means of Inler
In a "ba<;e plate" connection. the llangc of the :tbove-groun(1 strueturc is boiled to Ilange on the steel casing. Bolling can be done on either the inside or the outside of the (·asing. The struc!Ure can be plumbed by adju:.ting leveling nuts. Vibratory steel caisson foundations h:lve been uSl!d to suppon steel structures. The steel caisson is vibrated into lhe ground by the u<;e of a vibratory hammer. The steel caisson is commonly filled with reinforcing plates or "driving cars" for the purpose of attaching the vibratory hammer. Thc w:lll thickness of the vibratory steel caissons ,~hou ld be sized not only to resi~t the stresses due to the ground1i ne reactions, but also to prevent buckling or fatigue crJ.cki ng during installation. A minimum wall thickness of 3/8 in. ( 10 mill) is colllmon. The geotcchnicnl design p:.tr11metcrs for thc dcsign of vibratory steel caissons in looser soils nrc improved bc~'ause of densificalion caused by the vibratory installation.

,I

CIOJ) QUALITY ,\SSURANCElQUALITY CONTRO L CJO.I lNTRODUCTION A well-planned and executl!d quality assurance (QA)--<juality eontrol (QC) program is necessary to ensurc delivery of acceptuble material in a timely manner. The objective of the program is tt) establish tl1:lt matcri;lls are in confurmanee with the ~pcci li ca tions of the purchase contmcL A clear and concise contract between the Owner and the Fabricator is lIn impoJ1ant pan of the procedure necessary to obtain acceptable steeltr
C9.S El\'I8EODED CASIN GS CIO.2 QUALITY ASSURANCE Embedded !oteel casing foundmions ;Ire l\)u11(1 or regular polygonal tubul:tr steel members that serve as the foulldation to which the bouom of the steel pole is :mached. The bottom of the ~teel pole structure is attached to the casing by either a "socket" or "base pllltc" tyIX' connection. In a "socket'· type connection, the abovcground structure is set in<;ide the steel casing. The annular space. usually from:> to 9 in. (76 to 229 mill) between the stnlcture :tntl the steel casing, is then filled wilh either grout or cuncretc.

The Owner's bid docuJllents should outline the QA methods. lypcS of inspections. and remrds that will be required to dcterminc the acceptability of the product at each stage (11' the de!>ign, m;lfIufucturing. structure testi ng, and field construction proces:.. Qlwlity assurance is responsible for thc methods followed to eslab li ~h approprialc review ;Jnd interface wilh the Fabrit'alor's qualilY control procedures. This will cn~un: thilt the contr;lct c,ln proceed :.lIloothly, that proper cOllllllunication ('hanllcls arc e~tablishetl

39

DE."iIGN OF STEEL TRANSMISSION POLF. STRUCTURES

with {he respon~ible personnel to minirnitc confusion, that the Owner'~ requiremellts arc properly met. alld thaI proper guidance and adequme technical suppon are provided throughuut lhe period of the COntr.lCL The Owner should determine. by sile visit if required, that the F:lbricator's equipment :lnd proccss faci lities arc adequatc to mcet the requiremcnts of the quality assunlllCC spccific:ltion. that fabrication procedure:. :tre satisfactory, that lolemllces arc within specifieu limits, and that the ex isting quality control program i~ satisfactory. CIO.2.1 Design Hlld Drawings The lluality i\.\surance specification shou ll.! specify lilt: procedure for reviewing lhe Siress nnalyses of the mnin ~tructure and all component parts. including ullachmenls :md connections. The Fabricator's dmwings should be checked to ensure that they contain proper and sumdent informatiun for fabriC(ttiOIl and erect ion in accordance with the requirements of the Owner's specification. C IO.2.4 Nond est ructi ve Testing The Owner may specify that the FabriClUor furnish copies of testing and inspection reports. The Owner may also perform independent random ~1 ll1pl e t(,sting to verify results of the Fabricator's testing.

C I 0,2.5 Tolerances Dimensional vllriat ions Clln ancci the structural performance. euse of assembly, electrical clearances. and Slrue(ure appeanmce. The Fabric3l0r and the Owner should agree on the fabricu tioll IUferances that wi ll achieve the :.pecified performance. C ltl.2.6 Surface Coatings Blnsl cleaning of wcmhering steel structures m,\y be specified if :I clean
40

C IO.3 QUALITY CONTROL A qunlity control progralll should be establ ished in .1 1ll'lIlner thm provides open avenues of communica-

tion throughout the Fabricalor's plant. It should be hC:ldcd by a managcr with the overull authority and responsibi lity to establish, review, m::rintain, and enforce thc pmgr::rm. As a minimum . the QC program should identify key personnel who arc responsible for planning and scheduling, engineering, drafting, purchasing, production. lesting, sh ipping, :Jnd uppropliate quality control checl-s. The qU:Jlity control inspectors :Jre responsible for determining thm the produt'tl11eets Ihe level of quality cstablished by the Fabricator's sHmd.m.ls and the specific requirements of the Owner. C10.3,I Materia ls 111C Fabricmor's records should <:how all pertinent inforrnUlion on all component parts. Thi s l1l:ly t:lkc the form of a "traveler" on mujor componcnt~. The tmv· eler genemlly cont:lins pertinelll information on items such as materials. welding proccdures, welder's identification. type of inspection. in spector'~ test rcsult~, records of all visual nnd nonde~t ructive testing. inspector's identilic:uion. and other items agreed upon by the Owner .1Ild the Fabric.lIor. C JO.3,3 Dimensional Inspection Any structure th:1I is of unillue :tndlor complex design should be <:hop a~scmbled prior to ~hiprnenl. M::rting parH should be matchm::rrked. C IO.J,4 Surface Coating Inspcctiun The surface of stl1Jetu rul steel prcpared fo r spraying should be inspected vi~uully. The metallized coating. should be inspected for thiekncs.s by a magnetic thicl-nes", gauge. Any Illctaliil.cd surface Ih::rt exhibits v i .~ible moisturc. rust, scale, or other l'onturni~ nation should be reblasted bcfore spraying. Defective are:l.o; should be s!mdblusted clean prior to re:.pra ying, C)(ccpt where the rejection results from insufficient thickness. C 10.3.5 Weld I ns pl'"Ction Nol all inspection personnel nc('d to be qual itied to AWS QCI. Visual inspection may be performed by Ilollcertificd inspc("tOl's under the ~upervis i o rl or:t certified welding inspector (CW I). After gnJvanizing, nondestrut·tive weld testing should be considered to cnsure that there have been no

ASCEJSEI 48·05

adver.c eITccls 10 the finished proouct. This is especially 1mportant for large '-r' type "'cld jo inl" <;uch as base platc welds. Thc Fubrit'ator "Imuld establish wriuen nomlestfuctive testing procedufcs ,1Ild train nondest ructive te<;tlllg personnel in accordance with the guidelines of The American Society for Nondestructive Testing Rccommendcd Practice No. SNT-TC- IA. Nondestrucli\'c testing ClIn be used to detcct matcrlUl and wcldmg naw ... 17csent methods 11lelude vi'iual. magnet ic particle, dyc penctrant, ultf:l ~O O1 C . rnd10gmphic, and eddy cu rrent. Each of thcse methods ha~ inherent limitations. M(I~lIelic ptll'ficle {MT J is u practie:11 mcthod for dClccting. tight su rface cracks. MT in~pection should be in accordance wi th ASTM E709. 0)'1' IJelll'trwl1 CPT) is a \cry reliablc method ror deicetlllt!. any crncks or porosity th;1I are open to the test surracc. PT in~pection \hould be in accord,mcc with ASTM EI65. U1trasollic CUT) is the on ly practical method or delCnllining weld quality in thc base and nangc connection welds. It is al<;o vcry reliablc in detccting 'mall cr:lcks and internal n aw~ in other complctc penclnllion wcld~. II shou ld he noted that AWS DU t D I. JM docs not provide any spcci ne guidelines for uJtf;]~onie testing of plrnc less than 5/ 16 in. (8 mm ) thid.. or for welds using backing b:ll'S. It is recommended that Ihe Fabricator follow the procedure e,tablishcd by AWS DI.I/OI.I M, Section 6.27.1. 1n dc\eloping a specific inspectIOn procedure. Radiogrophk CRT) is II method that provides a permanent Tel'ord (lr Ihc tCSI resu lts. Huweve r. its usc I~ limited un many types or weldmcnt s (e.g .. base ;.md nangc connection s) whert! it is di i1icull. if not i Il1pO~­ "iblc. to position the tilm to record the emire weld Joint. [t is al~o po~siblc to miss tight nacks that lie normal to \he RT source and film. J::.tlth· t:/lrrel1t (ET ) tcdmiques have limited appli· cation in the detenninatioll of weld penetration and the detection of cracks. Additional infonnatiun 011 the limitutions und complemcntary usc of cal'll method IS explained in ANSIIAWS 111 . 10, Gllidc for Nondestructive In'r>Ce1iol\ of Welds.

C lI.O ASSEM DLV AND ERECT ION

CJ 1.1 INTRODUCn ON This commentary provides information supporting and explaining the rcquiremenl\ of Sect ion 11 .0. Additionul relevant IlIformutiOIl o n assembly and erection or steel transmission pole structures c:m be foulld in Appendix V. Section 11 .0 idcntific~ as~c mbl y and erect ion pr.lcticcs that arc: required 10 e nsure adherCllCl' to Structu re design assumptions and to prevcnt nctions that could compromise structuntl integrity, but docs not address ull aSI)CC{s of structu re in ~ tullation . The rormulation of a complcte in~tallation ~pec ifi ct1lion is the responsibility of the Line Designcr. Additional inrormation and reeomm C lldntion ~ for structure assembly and erection may be obt:lined from the [EEE Guidc to the Assembly and Erection of Metal Tmnsmission Structures (IEEE Publ icmion 951).

C I I.2 I-i ANDLl Ne;

The !.peei fi c;Jtions, d e~ i g n . und detuiling of pole ~Iruc· lure<; ~hould consider limits to length, sill'. and we1ght o f individual member; bccau<;e of shi pping. handling, telTai n, and e(luipmellt restrict ions. In selling weight limits. the Owner should con~i de r that aelllal :,t ructurc weights can deviutc by as much 15% from the Fabri eator ~ calcu l::ltcd weights because of mill and rabrication to lentnces. Pole sections can be storcd al a eC/ilralil.cd marshaling yard or althc Installation ,i tC'. Poles stored I.It a Ilwr,hal ing yard can be palliall} Of fully assembled prior 10 transp0l1ation 10 the Installation sitc. Care to prevcnt d:ul1uge to protel.'tivc couling" ~ h ould be taken in both the shi pping and the lmndl ing uf pole members. Pole ~ectio n ~ should be protccted from chai n tie·down~ on truck .. by pla<;tic o r nylon ~ hCCK Sli ngs for lifting should be nylo n or olher non metallic malerial. Pole secti()ns ~houlcl he ~I()red 011 blncks and cribbing to prcvenl cont'lcl with Ihe ground. The amount and spaei ng of the cribhl1lg ~ h ould be arranged In prevenl excessive deneclion durin~ ~ IOr:tgc.

C IO.J,6 Shipmellt and Storuge Tht' quality control program should cstnbl i,h prolit::lt specify the mcthod:.. m:lIcrials, documellunion. and Owner's special requirements ror handling, \tori ng, prescrvi ng, pad..:lging. pael.ing, marling. materi .. 1 releasmg, lmd shipment.

C II .3 SING LE PO LE ST RUCT URES

cedure~

The dec i ~io n 10 u~e aerial or ground asscmbly depcnd\ 011 ind i\ idual Silc Cll n ~ide r:1ll on~ and the Owner\ preference. To minillli7C the 1lt:...'tIto mstall equi pment in

DESIGN 01-'

~"EEL

TRANSM ISS ION POLE STRUCTURES

the air, davit arms, line hardw:lre, insulators, stringing blocks, ropl!s. :lIId ground~ ll" llpplicable arc usually installed on the ~trueture plioI' to erection. C II.3.1 Slil) Joints Poles a~senlblcd on the ground should have sections blod,ed level plioI' 10 joint a\scmbly, Care should be tllken to properly align the sections using marLs specitied by the Fabrica\{lr and:ls ~ h own on the FabnClltor':. dlUwings, and proper oriental ion of 10 prevent binding of the sections during m'erlapping, The upper section should be slowly lowered onto the lo .... er ..eclion. Mechanical rlle:ms to complete the Joint a..5>Cmbly should be employed as specilied by the Stru{'ture DeSIgner. The weighl the upper ..eelioll :llone can pl'oouce cmbling in the air. Special lubricants to aid in the 'J<;5>Cmbly of slip joints :lre genel'lJlly not requin.'d. If used. lhe lubricant should be nonstaining .101.1 water-soluble. The usc and type of lubricant .;;hould be approved by Ihe Structure Dcsigner. Sections should be carefully aligned 10 produce a light. even joint withoul rllaJor g:lpS between the two stttion~_ The u>;c of shims to lill gaps between poorly m:lted ~ection~ in a slip joint is nOI recommendL-d, Slip Joints tI'lUhfcr load through friction betwecn the seclion l'urf;lees, :1111.1 Ihe lise of ~him" will interfere with lhe IU
or

C I1.3,2 Holted Flange Joints The nange boilS slwuld be bmught 10 und to ensure

42

section alig nment. A pair of b(lilS o n oppo~itc ~ides of the joint should be tensioned followed by Jl ~ill1i1ar pair until all bolts urc tensioned. I'ropcr bolt tensioning in nange joints is required bec:lUSC of the cyclk nature (If the loading. Highstrength bolts arc susceptible to erne king when subji.."!:ted to high stress nuCtuatlOnl>, and prctcn'iinning of the bolts by the turn-ol'-nul or other upproved melhod ensures a more constant bolt l>t re s~ and prevents bult failure. Flunge pl:lleS used for pole joints arc rclath.ely thicl. as compared to materiul common to joints in olher type~ of structures, and acceptable fabrication misalignments or plate distortion C'1Il resu.lt in \ma ll gups between the Ibnges, even after fill:ll bolt lemioning. The~e gaps, within permitted limits. are not injurious 10 the load trnnsfer capability of the joint. L:lrgcr gap:. may be filled by shims. C II.3.3 Attachments to Poil' Scel inns Some :1ttachmcnts to pole section~, !>ueh as arms that usc box or bmdel type cOl1l1ections in wh ich the bolts :ICt 'IS pin connecturs, do not ha\e true 1':lying ~urfaccs and :Ire intelltionally I{)()~­ filling. C 11.3.4 Ereclion of Assembled St rllctur'cs The :;tructurc should be ]Hid out at tht: installatIOn site 10 minimize erection efforl :lnd emuTt" safety. A tcmpornry lin\.. hetwecn slip-jointed section .. should be inlolallcd to prevent loosening or ~cparat i ol1 of the ~cc­ tions during lifting, The jacking allachmelll nuts C;1I1 often be u,cd for allnchmcnt of Ihe linl.. Polc\ may be ere{'ted u'iing lifting lug:; (if installed) or a choker. The lift poi nt for the choLer will be field-determined and i<; dependent upollthe assembled :lrr:lIlgcl1lent of the pole, including acce~sorics su{'h :Ili IlIle hardware. Tall, ~Iendcr poles, such as guyed stmctures. can require two-point lifting or other sp(:cial rigging 10 prevent e}{ce,,,i\'c dcncction andior stress during the lift.

C ll.4 FRAJ\m TYPE STRUCTURES The 1110'.1 coml11on type of fnulle structure; is lhe H-fmJne. Another lypic.11 fmme ~lructure b the fourlegged A-frame commonly lIsed a~ a )'Ubst:ltl0n lerrninalioll stru{'ture. The assembl y proce\s for frame stmClUl'es is simi lar to th:1l lIsed for ~ingk pole structures. and the S:11lle djscus~ion and recol1llllend:ltions !!i\'en in Section e l1.3 'lpply.

ASCFJSEI 4R-05 e lI A. 1 Slip Join ts in Frmnc." Shp-jointed leg" of fmmc structun:s should be assembled on the ground 10 .. lIow variations in leg lengths caused by ~ I ip toleruncc to be L'Ompens:llCd fur by adJu:>ting the anchor Ixlll ~y~tell1 (lr embedment length. C II.~ .2

Erection Crossarms cd. ean be 1I1":llIed on the ground ;lnd the stnlcture erected a:. a Ulltl. Special C'In: ~hould be tal..en 10 main!:lin structure geometry. The correct di"tnnee between the legs should be ensured before lightening the eonncclions. A ~preader b 10 align connections. TCI facilitate the erection and a....embly proce",. maximum adjust ability should be Illilintamed m u fr::lllle stnlcture during as~embly by leaving :111 conm.:ctions loosely boltcd. When a:.:.cmbly h COI11plete. connection bolls should be lightcllcd and the ~tnlctllrc checked for vertical alignment (either plumbed or ml..cd a~ required by the Lille Designer).

e lI.S. 1 Anchor Bolt lIud Ilasc Pla te Installa tiun The anchor boh and bnc;c plate foundation ~ystem typically uses two nuts to attach ench anchor bolt to the pole balie platc. One nut is sct below the b:l':C plate. and Ihe other nut is scI ahove Ihl.' base plate. The ba~e plate docs not directly bear on thc foundnlion surfacc. and bearing i~ nO! considered in the ~lmelUre design. Prior to structu re erection. one nut is inst;Jlicd on e:lch anchor bolt :lnd turned dl>wn on the bolt to .. llow 1Il:.lllliation of thc pole base plate :lnd thc top nul. The pole is lifted and 'iet on thc anchor bolts anJ bottom nuts ... lid thc top nuts arc il1\lalied and hand tightened. Thc pole is chccked for alignmcnt and plumb or. ir .. compensating dellf..'Ctioil is beillg SCI, the p(ll(' i~ lelllled to provide the desired dcllCClion by .. djll~t i ng both top and bottom nuts ;I~ rC(lui rcd. For frame ~l ruc­ tures being assembled in the air. the anchor bolt nuts llhould be left snug tight to allow for movement until lIs~elllbly i:. complete. Tightcning of anchor bolt nut~ is aecolnpli~hcd by ~nug Itghtening all top nut" fi,,1. and then snug tightening all bottom lIuL~. Bottom nut.s arc checked to en~urc firm contact with the b:lse plate. and then all top nuts are tightened in :ll.'curd:m(;e with the Fnbricntor's rcqui remcnt~. Following illstuli
C I1.6 GU VI NG C II .5 INSTAI.L ATlON ON FOUNDATION For reluted information concermng helicopter erection, ~ee Appendix V.

C I 1.6. 1 G uy Anchor Lucation The accurate location of guy anchors i<; erilicallo the proper distribution of load~ in the :-,trUClUrc.

DESIGN OF STEEL TRANSMISSION POLE STRUcrURES

Changes in guy angles. either hori7onlal or vcnita], tlnd guy length~ can cause dramatic changes in SlnICture forccs from those predicted in design. It is vital thm any field condit ions thill requirc a change in guy !ll'01llctry be referred to Ihc Structure Designer fUl' review.

C 11.6.2 Guy Installation The Structure Designer ),hou ld identify to the Line Designer the need for timely guy installiltion and :lily temporary guying requi red to provide structure stability prior to line completion. Some designs requirc illllllcdi.:ne guy inst:ll1mion 10 resist evcn routine wind loading. while othcr designs use guys only to resist :Ipplied conductor and ground wire loads. Additiona! information for insltlllation of guys can be found in Chapter 7. "De~ign of Guyed Electrical Transmission Structures:' ASCE Manunls and RepOr1s on Engineering Practice No.9 J.

necessary to remove rus/, grease, nnd othl~r roreign mailer. It might be desirable to lightly ~a lld the edges of Ihe repai r nrea to feather the touch-up pain! into the ex isting (·oating. The damaged ;Ireas should be dry prior Iu cO:lting. If d<Jmage is limi ted to the finish or top CO:.11. apply 011C coal of properl y mixed paint to the required dry film thickness. If damage includes the primer. the approprime touch-up primcr should be appl ied to Ihc required dry film thickness
C II.7.2 Grounding 111 )'urne L:ase~ bonding jumpers lIl
C l 1.7.4 Unloadcd Arms Conductors or ground wires all;Jched 10 anns provide a vibrmio n dampening ene,·! to the arms. When conductors or ground wi res will n01 be in~\4Illed on the lIrms integrally with the line construction. the arms might be susceptible to damage from wind-induced oscillations of the unloaded arm. The symlTlctrical slwpe of the arms and the absence of th(' vibrillion dmnpcning effect of ,ltIa('hed (·ondu(·tol"S, grou nd wires, and assemblies ('un res ult in damaging oscillatory movements. cven in relativcly low wmd velocilies. The tension-compression cycling of Ihe arm!; can eausc L1t igue cn}(;ki ng and :.1 rm failu re. When arms ,ll"e inst;Jlled without the planned conductor or ground wires. it l1l
C I 1.7.3 Coa ling Re pair The damaged area of il galvani:.:ed coati ng shou ld be cleaned using a wire bmsh and solvent. if necessary, to remove rust. grease. nnd other foreign mailer. Whell dry. Ihc llrca should be coaled with a cold galvanil.ing product. as approwd by the Owner, with as many coat), <Jpplied us necesSilry 10 reach the required dry IiIm thid..ness. Refer to ASTM A780 for ildditiollal information. The damaged areas of paint coaling!> should be cleaned using a wire brush. serilper, and/or solvent as

C l1.7.5 HardwlIr(' Installatioll Aeolian vibration of conductors and ~;tillie wires i'i a common occurre nec. The severity of the' vibratioll is dependent upon Ihe tension-to-strength mtio or the installed eonduclOrs, span leJ1g l h~, wind speed. ;Jlld average annual minimuill tempcmture. It is common praclice W req uire inst:ll l;ltioll of vibralion dampers within IWO weeks of conduclQr inslallalion. Without damper insl:.1llalion. wi nd-induced oscillations could be transmitted from the con du ctor~ :tnd cause vibmtion of the s tru ~·ture componenl.s.

C II.7 rOSTI!: RECTION PROCEDURI!:S For <Jddilioll:tl inlQrmation concerning recommended maintenance practices. refcr to Appendix V.

C 11.7.1 Inspcctiull Struclures a~selllblcd in the air. where joi nts were initially assembled loosely bolt('d, should have:tll joints tightened and inspected for conformance with the Fabricator's requirements. Damage 10 protective coatings should be noted :lIld touch-up repairs should lx' made. Final checks of :l lignmcnt and plumb shou ld be made.

"

AS('ElSEI 48-05

APPENDIX I NOTATION

The following symbols are used in the standard:

moment of inertia about 1'- Yaxi~, in.4 (mm·): torsional co n ~ t llnt of cross '\Cetio n. in.4 (mm 4 ): ctTective length facwr: ~1cndernes~ r
I,

J K

cros~-sectiona l

afca, in .~ (0101 1): total ant·hor bolt cage net cros~-sectiona l area. rn.1 (m m ~):

A A~

A"

A, A. A, A,

~

~

~

A '!f<'(~)

A,

BR

,

c, c>

C,

~

~

~

d

d" /)"

E

I., F.

J"

~

~

f" F

•

f:

-

,.: I' " F, F dOi

F

"

J:

F, F, 1

~

~

~

11«-.

'Il( , I,

~

foundmions effective projected stress are;1 of concrete, in.~ (mm1); gross eross-seclional area, ill.! (mm2); net cross-sCCtiolllll area. in.! (JI1I1l~): cross-sectional area at root of the threads. in.! (111111'): tensile stress area of bolt, in. ~ (mml); 1"C(luired tensile stress are" of bolt. in.1 (mm!); tensile stress nrea. in.1 (rnlll~): eOcctive bend mdius. in. (mm ): distance rrom neutral ax is to I>oint where stress i~ checked. in. (mm): dist
KL/r L I,

L, L,

L,

M

M,

(Illrn~N):

M,

M,.

"

~

p

P"w.

RBS

~

Q r

" ,

=

~

T= T,

V II' '\1

.\',

"

~ y

n 'I'1-

e

~

bending mOlllcnt about x-x axis. in.-kip (II1m-N): bendi ng momcnt about Y- Y axis, in.-kip (IIlrl1-N): number of thrCllds per unit length, in. (m m); total number of boIH:; axial load. tension. or comprcs~i() n , on member or guy, !..ips (N); ,lclllal force transmitted by bolt or pin. kips (N): max imum tension force perm itted in Ihe guy. kips (N): minimulll rated brellking strength of guy. kips IN); moment of section abotll nelltrill axis, in .' (mm'); governi ng radius of gyratioll, ill. (111111); cellter-to-center spacing between bolt holes. in. (mm): thid,ness of elemenl, in. (111 111); t(l)"<;ional moment , in-kip (mill-Nt boll lensile force, kip" (N): shear force, kips (N): Illl width of clement. in. (r11Ill): d i~ta ncC' (lfbolt from Y-J' axis. in, (mm): distalll'e of bolt from X·X axi". in. (Illm): unit factor as specified in the text: lInit fac\()r as speciticd in the text: ratio o r requirelltensilc !lrca to the gr(lS~ area of the anchor bolt: unit ractor
DESIGN OF STEEL TRANSM ISS ION POLE STRUcrURES

API)E NO IX

n

PROPERTIES Of VA RIOUS TU8 ULAR SECfIONS

r = O.354·/J

At ""'3. 14·O·( I , = I , = 0.393' I)"

Q

x-l- -+--II-x C, = 0.5 . (D

C,

=

+ I)

. co~(a)

0.5 . (I) + /) . " in (u)

y

o

0.637

M ax.- - - I, /J . I

I

Max. ~ = ", 0.",63: :7",·"(,, IJ_+'-'.!.il J lOI'1)

FIG URE A- Ii- I. I'ropertics or Round Scclions .

A ~- 3. 1 9·0·1

I,

z=

1'= 0.356'0

I, = 0.403·0'·

Max. Q "'" 0.634 I, /J. I

I

C, = 0.510 · (tJ + t)· <:o:;(al

+ t)·

C, = 0.5 10· (/J y

o

(/

11 .25"

C Max. J

= 3.21 .

/J .

• /)

r = 0.358 . J)

I

Q

co~(a)

+ /) . si n(a)

Max. ~

=

~O",.6.:::22=::-,·,,(D,-:-,'...:'~) (J)' . I )

j

y \I'

o

0.63 1

Max.- = - I, l> . I

. ,

C, = (l.5 IS . (0 I /) . C, = U.S IH· to

=

0.268 . (0 -

1-

2 . IJR)

FI GURE A- II-J. r' rOllCr lics or Oodccagoll:l l ( 12-Sided I)olygon) St.'t.- lions.

At

r

3.32'0'/

I , = l , = 0.438· I)"

I

c. = U.541 . (I) + I) .

0.364 ' 0

Q

0.6 18

C

0.603' (I) + /)

Max. - = - I, f) . I

COS(lI)

C, - 0.54 1 . ID I II· si n(ul

Max -

' j

y

4"

(I) I

O.199·(D-1-2· BI()

I\'

1,= 1.= 0.4 11'0 1

o

0.628 ' (lJ + I) =

FI GURE A-II-2. l)ropcl'lics or Hcxd ecagoll:l l ( Hi-Sid ed Pulygon ) Sccl inns.

A~

x-l----r=-i---r- x

~ in ({/)

IV

=

(D'·/)

0.4 14· (D - / - 2· IJR)

F IGURE A- II-4. Ilropcrtics or OClagona l (8-Sided I'nlygon) Se<"liolis.

ASCflSEI 43-05

A. = 3.46·

I,

x-+---tL--~-x

I,

r = 0.373 .

f) . /

0.481·D 1

C, - 0.577·

. /

Q I,

0.6<'6

£. =

~O=.5-,-77",,·"(0=-;-:,...:,,,1

Max. -

0 ./

CD + I) . cm(a)

C , = 0.577 . (0

+ !)

. ),in(o)

y

Ma\.

1

1\1

o

/J

(0 1./)

= 0.577 . (D - / - 2 . IJR)

FIG URE A-If-5. Properties 01" Hexagonal (6-Sidcd Polygo n) Sections.

w

I"

1

1/ 'y x

,- -

A ~-= 4.00·D·t

I , = I , = 0.666.

C,

z=

0.707 . tD

r = OAOS . D

/) 1./

+ I)

o

II

45"

I,

D .t

. eO~((I)

C, ,., 0.707 . (D + I) . sin(a)

y

Max. Q = 0.563

C 0.500 . (/J + r) Max.) = (0' . /) 11"

(0 - t - 2 · IJR)

FIG u nE A-II-6. Prupcrtics of Sqmll'c Sectiolls.

NOfE: For polygon ,eetion .. of Figs. A-II- I to 6. all properties except nm width (w) :lSSllllle sh:lrp eonll':n..'tI scr.::tion. Nohll ion for Appendi x II gross area: A, angle between the x-ax is and the corner of the polygon; ciTect;ve bend radiu~ (actual or 4 tim('!; I. whichever i~ !.m:l11cr): distance from y-axis to point ; C, dislallce from x-axis to point: C, J) f)~ - / ,.. mean diameter (measured to midpoint of thid.. ncJ;S across ntllS on polygonal sect ions); outside diameter ( nl('a'lIn~(t :u.:ms~ n:u, nn D" polygunal sections): I momen\ or inertia: polar moment of incni
"

~

"" ~

Cl l "......

, "

..hear Strc!>s: \
t~ I GUR I<:

1\-11-7.

Ty pi cu ll)illl c lI~ iull ~

Ilolygon Sections.

uf

DESIGN OF

~'T~EL

TRANSMISSION POLE $TRUcrURES

APPr. NDlX III HO RIZONTAL TESTJNG 111e structure i" no rmally placed in a horizorual posiIron a'> shown III Fig. A- Ill- I below. An assembled pole is Iypically boiled to an Identical bottom section. 1'111" bollom section i ... secured ncar the base plate 10 3n uplift foundation whIle the other end re .. ts on a compre,>sion pad. One or mo re locations nlong the shaft will be selected tiS the load pulling point!;, The pUrptlSI; of the load pull(s) will be to duplicate maximum design stress at all critic:!1 points in the shaft ba~ed on the cross-sectional geometry of the shaft and yield strength of the m:lterial. (Criticall)()inls Ol re 111Il~c pollllS (In thc shaft with the highest slress.) A;
pression pClIllts, E:lch i nc rl;mcnwllO:Jd should be held for the l'Cquired time heron; proceeding to the next lo.ld increment. Arter tesling the struclUre. it should be unloaded [0 the dend load 1lO finnl d..:Oection rcadlllgs (;.111 be taken. A final in~JX-'C[ion should be made of the structure.

AI)PENI)IX IV HEADED AN CHO R HOI..TS For headed bolls. malerial,> U'\4..-d should be limited 10 ASTM A36. A I93 (gr:lde 87), A307 (gmdc- B). A315. and A354 (g.mde Be).

I-Ieaded Holts Devciopment Length The developmcnt lenglh ror he:ldcd den ned as the following:

boll~

iii

(Eq. A IV- I ) where

Test ECluipmc nt The ve t11ClIi loads ;Ire pulled 31 predelerm ined points along thc shaft by crane'> or olher suitable pulling devices. Loads 1ll3Y be Illeasured using calibraletlload ('ell ... luclIted in Ihe pulling lines, A tr-Jnsil set up a s:lfe db,lance :lW:lY from the testlltruclur..: may be lIsed to measure dcncctiolls,

T('sl I)rocedu rc ror I'ole Test Oead Load Increase. Calcul:ltion of test 10:ld ... cornpcn'>:lte for Inc dead weight of the strul'ture In il\ hori7.0lltal position. f)(!.vigll /..0(11/ Test, Incn.:I1lClltlll 1(J:l(ls should be pulled, 3S indiCUled in the tes t requirements. with deOcl' tion l'Cadi ngs being tai-..en at prede te rmined points along the structure and at the uplift and com~hould

LOAD PUll POINT

HOLO-DO'M--J BAND

IJ = embedment length of anchor bolt; and (/

boh diamete r.

Headed anchor bolt" should have a<; a minimum a clear cover (If I wo bolt di:lmetc-fS :md 3 in. (76 mill) clear cover bel ween the anchor bolt~ :U1d reinforcing steel.

Background In lieu uf following AC r , methodology, whe r..: one must en"lurc thai there is sullir.:icn\ concrete 3re:l 10 resi't the tensile forces, the ubJect ill to get the tcn~ilc load from the bolt [0 the adj'lcem \'enit'lIl reinforcing b3r~.

Twemy.. nve d iameters for a de\·clopmelll lenglh for a headed anchor bolt will closely :lpproxima!e the

REACTtON BEAM (USUALLY AN IDENTICAL BonOM SECTION)

COMPRESSION P~\D

FI GURE A-Ill- I. Horil.ontal Test Setup,

ASCEJSEI ·HI·O.'i

deyelopment length for the rebar followi ng ACI 318 plu!> 3 in. for lOp coYcr and 3 in. ror coyer octween rcbar and anchor bolt. In this way the Stmelurc Designer wilJ provide the Foumhl\ion Designer adequate boll length to provide sulTicicnt vertical reinforeement ror calcula ting reinforcing requi re ments.

AI)I'ENDIX V ASSEMBLY AND ERECTION IntroduClion '111is appendix provides supplemental informat ion to Section I I concerning the assembly and erecti on of steel trallsmission pole SUlleturcs. Helicupter E rection I klicoptcr erection requires eoordi n3lion between the OWller and the Fnbricator as to the techniques to be employed, weight limitations, special brackets, and mher simil ar item::. unique to helicoptcr lifts. Special guidc~. whil,.·h ctln be provided by the hel icopter C(lIltmctor. can elimi n:lle the need for workers to be under the !>tructurc as it is bei ng set or a~ set·tions :Ire being ndded. Helicopters can be used to transport pole sections from the m:m;haling ynrd \0 the structure site. or they can be used to erect st ructures nlready tnlllsported to the si te. This In\ter technique can be e mployed whcn restrictions limit the SiLC of constructioll Ctluipmcm at the pole site. To lift the st rUl;tUI'C, a sling is aHached to an elcctrically operated hook on the undcrs ide of the hel icopter. A load cell is normally uscd to monitor the en'eetive weight of the pay lo:!d, which includcs the eOcct!) of the ..erodyn.unic drag and rotor down wash. The 11001-. is controlled by the hel icopter pilot , who ca n rele,lsc the load if necesS>lry. Thc "li ngs should be attachcd 10 the structure so as to not overstress or excessively ddlect or distort the structu re. Stnlcturcs \(l be guyed can be flown with guys attached \(llhc structure. Guys .~hould he ~'oi!cd and .. ttached to the Structure in ~ue h a man ner as to prevent contact with the grou nd, trees, fe nces, or other objects during night. Coils should be reachable from the ground once the strut·ture is sel. and each guy should be marked 10 identify the proper ground anchor for att:lchment. Unguyed structures shou ld be secured on the foundation prior to release of the ~lfu ctu re by the helicopter. Guyed struct ure, should also have guys secured to thc anchors prior to release by the helicopter.

In-Se rvicc Struclurc Maintenance and In SI)Celion After installation, a routine program of st ruClun.: inspection is recommended for all steel tHm smissiOI1 pole structures. This program should be designed 10 guard ag:l i n ~ t structuf(\1 degradation resu lt ing flu m environmental wear. corrosion, accidental damage. and vandali SIll . Includcd among the ite ms in a typical routine inspection program arc the fo ll ow ing: I. Inspect ion of protective coat in g~ and lOudl-UP of damaged areas; 2. Inspection of self-weat heri ng st ructures fnr localized areas of cont inual moisture and cxct:ssive I;orrosion; 3. Visual inspection of bolted COlUleClions llI.Il{l ~(Xlt check of bolt tightness in selected con nections: 4. Visual inslxxtion of welded c() nn ec t io n ~ and scams to detect cracks: 5. Visuol inspection of the groundline area wensure that soil and vegetation arc not in contact with or otherwise creating [\ corrosivc environment for the steel st ructure; iJlld 6. Inspection of cli mbing hard w
fon;cs by structul'Cs :tnd structure mernbt.'rs Ciln resu lt in osc illation of slender i\mlS, poles. or othcr clements. 1~111 sl":cI pole structures used for ~u bst::tt ion lightning masts arc examples of a structure type commonl y subjected to noticeable wind oscillat ions. When~ such movement is predicted or observed wi th a pole or a SU'ucturc member. the installatioll or vi br(\\ion dall1[)ing devices might be considered to prevent fatiguc damage. When the potcntial for such movcment is anticipated by the St ructure Designer. decreilsing the slenderness ratio of the member (L/ r) CWl be con~idc rcd as an nlternative to the installntion of damping dcvicc~. AUf/clled C(ll!(/U CTor~' mul Slofic Wires. Aeol i;m vibl11-

tion uf aeri,,1 con du c t or~ and st:ltic wires is a cummon occ urrence. T he se\'erity of lhe vibrat ion ;s dependent upon the tension tu strength ratio of the installed conductors. spnn lengths. wind speed. and avcrage annual minimum temperature. Where such vibr:uiolls ,Ire caleulnted 10 bc or such il Illilgnilude fil nge thilt wi re damage could occur, it i.~ common practice \{1 install yibration dampers. The use of Ihe~e dam pe l~i should

49

DE.
also be con,idcred 10 prevent stmclure damage rrom vlbr:lllOn
APPENDIX VI SHAF1'·TO·FOUNOATION CONNECTION Rase Platt's Anal)sis Considerations Currently there lribution in the basc plate. ll1ercforc. when :l hole exists in Ihe l.'Cnter or a b,l\t' plate. itli effect should be t'Onsid· ered 111 the buo;e platc an:llysis.

'"

Resultanl [nads for each indl\ idual :ll1ch,)r bolt are nceded to cakulme Ihe stresscs in a basc pilltc. It i<; normall) ,Is .. umed thai thc$C anchor bolt load~ will proouce' a unifonn bending stress.!/.. along Ihe efft!cli\c pol lion of each of the bend lines analY.led. To calcu latc the strc"s (llong :lny bend line, the following p~lrameters necd to be eSI(lblished (reference F ig. A-VI- I ): ,alue~ (ontri butmg moment along the hcnd line: ~hone'n dl!olance from anchor bolt (0 10 Ihe bend line: ,1fId length of bend line (depe nding on the Sh,lpe (If Ih,t! IX)]C. the s hu pe or lhe buse plale. and k),

k - numl>cr (If om:hor LXIII load (BL)

c, bel,

>=

Figun: A·V I·- I shows three posslblc bend lines on a base p];ltC. Thc bending ~trc~~J~ for:ln M~urllcd bend li nc can he calcul:'lIcd by Ihe formula

whert~ .., .. is the h:ls :lnd "BL" i:. the bolt load. Thc minimum bllS('; platc Ihid.lle~s i~ determined by keepl1lgf~ below the yield slre5S f',. To dctenl1inl~ In ,~, the prcviou~ equ::luon can be rc\uillen a~

'.""

- .J(b.:,.-,)(BI41

+

BL:-e:'~ + ... + BLle,) CEq. A-V I·2)

or

Anchor nnll I.lI:1d Clllcu lllliOI1 The IOC:Jitlon of the anchor bolts is usually a functIon of Ihe required cleur-mce bel ween thc anchor bolt nut~ and the polt:. the minimum ~padng allo\\oed

,-

,

I

, ,. )

•

. ---- 3

F IGU RE A· VI- I. Exnmple or Possible Uend Lines.

ASCEISEI ·HI·OS betwccn anchor bolts. and the number of boll... resist Ihc lond. The clearance requirements ~hou[d be in accordance wilh ArSC. keeping in mind the ba:;e weld detail and manufacturing tolcmnccs. The rnmimum spuclng between ;mellor bolls !;houJ d be in accordance with ACI 3 18. The number of boll .. i... dependent o n Ihe reactions at the ba<;c or thc pole a~ well as lhe ]oclltion o f the boilS. II is commo nl y assumed thaI the ba~e plate behaves a~ un infinitely rigid body. lind thus the uXlal load III anyone anchor bolt (i). BL,. c:m be cnlc tltated r~qum!d 10

lot,.\',

""I,X,)

BL, . . . ( -~--+-- A Am lac, fOC I
(Eq. A.V I·})

where

p ... toltll verlic:!1 load '" the bll~e of the pole: ba~c bending mOlllent about X-X ax i ~;

M,

AI, -

\,

ha~c

perpt!ndicular di stance X-X axi~ 10 anc hor boll: nCI nfca of anchor bolt (i); tOlal anchor boll cage nct cross-sectional
1/1("< =

L (A ..wr~ +

.1',

•

.-,

I,) - anchor boll c:lge mument

of incrtia about x-X

1/1(,

•

L (A.o;'J.I'; + I,)

.- ,

ax i ~:

anchor bolt cilge moment

of inen ia aboul y. Ya"I!';

" tot;!l num ber of llnchor oolh : and I, = mOIllCnI of inertia of anchor bolt.

by Ihc following formula: p

A,.n All(

bo.:nding momcnt abou t Y- Yaxis~ perpendicular distance y. Yaxis to andlOr bolt;

Sincc thc momcnt of inenia of un individ ual ancht\!' bolt./" is nonnall y a \cry small percentuge of the totul ll1lchor bolt cage moment of inenia (lsc. or 111(-.)' this Il'rm is unen ignored whcn cakul;J'ing I/IC' ;md /"" Figure:- A-V I-2 illust rates tho: U5e of Eq. A-VI-3 In establi ~ hin g individual anchor botllo;ld~ fOf a gi\ cn pole base reaCllon .

uu u u

BL~ ~ '18L 2

) BL

•

FI GUHt:: A··VI-2. AncJwr Bo' t Load ClIlcuhtlion.

51

INDEX AISC. See Amcric:U1 Institute of Steel Constnll;lion ASCE. S('(' American S(lClety of Civil Engineer.; 3eolian vibration 2,21. 23. 44. 49 Amaictm Institute of Steel ConstructIOn 2, 24, 30.31.51 American Society uf Civil Engineers 2,:;, 2 1. 22. 25 American Welding Society 2. 10. U. 14.34.41 anchor oolts 15.19.37-39.43,48-49.50-51 area, ctl'ecti\,e 10-12 asscmbly 14.19-20,35.4 1-43 ASTM IllIem:llional 1-2.4-5,7,8 AWS. SI'e Amcric3n Welding Society 3xial stress 6. 16.?7 bll"e plute~ 12, IlJ, 3D, 32, 43. 50 I'!cnrn member 5-6,25

beuring Slress 9. 30-31 bending stres.;; 6-7.28,50 blast clenning 2, 17 bolt holes 14,30 bolts 8-9. 15-17,30. Sl't' aIS(J anchor bolts bolt sp.'1cing 16: minimum 9,30-31.50-51 buckling :25-'29 comber 2,23. 33 Chorpy V-notch test 4, 10. 15

drcumfcrcntinl weld 2. 12 climbing I>fOvision~ 4.24 cOllting 17,18. 40: repatr 20....4: inspection 18,40 complete fu~ion 2. 1'2 complete joint pcnctfmion 2, 12 comprcssion 5-6. 11,25-28 connections 8, 12. 15.30-32.37,50-5 1; analysis of 4 corrosion 13. 33. 38 coupon tcsts I ... cutting 1J,33

dead-end structures 22 dcOCClions [5.36 design 3-4,25. 3X; quality :l%UI':mcc 17,40: restrictions 23 design [oati s I , 17. :21. 32. 34-35_ 48. See (11.w factored design loads design stress 2, 4. ~. II, 29. 30-3 I deuliling 32 development [englh 16.39,48-49 dlrecl-emocdlleu pole '2, [7. 19.37,39,43 dodccngonal member 5, 26, 46

drawi ngs 12- [3.32.40 edge di stance 2.9-[0,30 -3 1 clastic method t)f annly~is 22-23 embedde d casings 17,37,39 embedmem [7.35.38,39,43 l'rcctiun 14 . 19.35,4 1-43: he[icoplcr 49; uJ'awings 13. 19.32

fabricminn 13-14.33-35 Fabricator 2. 12- 13.32.39: (Iuulity COllU'oi [H. ... 0-41 f
19-20.23,39,4[-44

joint-use upplic;ttion:. :2 [ lame[[ar learing 2. 3 1 laternl rc:;istlmcc npprouch J 7 I c ngt h-m'~usurcmcJlt method 8. 15 limiting ":tlues 5 Line De-;igner 2.... 3-44 load npplication 14. 35

DESIGN OF STEEL TRANSMISSION POLE STRUCTURES

10
shield wire 2, 3. 21. 2::!-23 <;hipping 18.40.41 <;hop del:1il dr.lV. ings 2, 13,32 slendeme~s ratio 5. 49 shpJoint 2,12.19.31-32,42,43 slol wcld~ 10-12 snug-light 2, 19,42 stability 2: locnl buckling 5, 25 steel pole ~Irue\llre I. 3. 24, .13, 39. 49 stmin slrUl·tures 22 <;tre<;s ::Ire'" 9. 16 stress c:1lculatlons 4 stress. combi ncd 7,29.38 slrw.:tur:ll Ul1<.IIysis 4 , 22 SlrUl·\IIn.: components 1,23.37 Structure Designer 2,4. 1::!- 13, I". 15,3:2, 34.38 sll~pclI~ion structures 22 tensilc stress 4-5.7.8,9.15-16,30-31 Icn~i\ln force 7.29,38 Test Ensineer 2 t e~t illS 8, 14. 17.25, 26, 32. 34, 40-41. ·Hl; report 15, 36-37; quulity :1~Sllrant'e 17 test 100Ids 14,34.35-36 throat thickness 10 through-thickncss stres<; :2. 31 T-joinfs 3, 12.18 InIl1~mis~ion lines 2 1-22 Inm'imissiml ~I ru clu rcs 22. 24 -:25, 30 lrus<; member 2.5,25 tubularlllcmbcr 1,4.23-25.32 \erifieation. te~t 32 \ibmtion 49-50 \\.'cJded Cl)IIlleCliolls 10,31 wcld .. 10-12,13. 14.34: qualit}' l.l!'>SllrJllce 17: in,[>Cclion 18,40-4 1 weld strength 11 -12 yield mcss 4-5. 8.15.29,30-31