1. T.chhay
I. esckþIepþIm
Introduction
1>1> karKNnaeRKOgbgÁúM Structural Design
karKNnaeRKOgbgÁúMsMNg;GaKar eTaHCaeRKOgbgÁúMEdk b¤eb:tugBRgwgedayEdkk¾eday KWtMrUvnUv
karkMNt; nigeRCIserIsmuxkat;smrmürbs;Ggát;eRKOgbgÁúMTaMgGs; edIm,ITb;Tl;nwgbnÞúkxageRkATaMg
Gs;EdlmanGMeBIelIeRKOgbgÁúM. kñúgkrNICaeRcIn sßabtükarmantYnaTIrcnasMNg;EdlrYmmankarerobcM
cMnYnCan;rbs;GaKar nigkarerobcMbøg;tamCan;nImYy² ehIyvisVkreRKOgbgÁúMRtUveFVIkarkñúgEdnkMNt;rbs;
karrcnaenH. CakarEdlRbesIrbMputKW visVkr nigsßabtükrRtUvshkarKñakñúgdMeNIrkarrcna nigKNna
eRKOgbgÁúMenHedIm,IbBa©b;KMeragedayTTYl)annUveCaKC½y. dMeNIrkarKNnaeRKOgbgÁúMRtUv)ansegçbdUct
eTA³ sßabtükrCaGñksMercnUcesaP½NÐPaBrbs;GaKar ehIyvisVkrRtUvKitfasMNg;GaKarmindYlrlM.
visVkreRKOgbgÁúMRtUvKitCacMbgnUvsuvtßiPaB bnÞab;mkKWkareRbIR)as; nigesdækic©. esdækic©enAkñúgsMNg;KW
sMedAelIkareRbIR)as;nUvsMPar³ nigkMlaMgBlkmμy:agmanRbsiT§PaB.
karKNnad¾l¥KWTamTarnUvbøg;eRKageRcIn EdlvamankartMerobGgát; nigkartP¢ab;Ggát;xusKña nig
eFIVkareRbobeFobnUvlkçN³esdækic©rbs;va. sMrab;bøg;eRKagnImYy²EdlRtUveFVIkarGegát eKRtUvKNna
muxkat;rbs;Ggát;nImYy². edIm,IeFVIVdUcenH)an eKRtUvkarviPaKeRKOgbgÁúM nigKNnakMlaMgehIynig
m:Um:g;Bt;rbs;Ggát;nImYy². CamYynwgTinñn½yTaMgenH GñkKNnaeRKOgbgÁúMGaceRCIserIsmuxkat;sm
Rsb)an. b:uEnþ munnwgeFVIkarviPaKRKOgbgÁúM eKRtUvsMercCadMbUgnUvsMPar³sMrab;eRbIR)as;kñúgeRKOgbgÁúM
EdlCaTUeTAmanebtugBRgwgedayEdk/ eRKOgbgÁúMEdk nigbnSMénsMPar³TaMgBIr. Cakarl¥ eKKYrerobcMnUv
CMerIsénkarKNnaBIsMPar³TaMgenH.
enAkñúgesovePAenHmankarENnaMEtkarKNnamuxkat;eRKOgbgÁúMEdk nigkartP¢ab;Etb:ueNÑaH.
visVkreRKOgbgÁúMRtUveRCIserIs nigepÞógpÞat;RbB½n§eRKOgbgÁúMTaMgGs;edIm,ITTYl)annUvkarKNnaRbkb
edaylkçN³esdækic© nigRbsiT§PaB.
munnwgniyayBIeRKOgbgÁúMEdk eyIgcaM)ac;sÁal;nUvRbePTénGgát;nImYy²rbs;eRKOgbgÁú<M. rUbTI
1>1 bgðajBI truss CamYynwgkMlaMgcMcMnucbBaÄrEdlGnuvtþRtg;tMNénGgát;xagelI. edayrkSanUv
karsnμt;énkarviPaK truss ¬tMN pinned nigkMlaMgGnuvtþEtelItMN¦ Ggát;rbs; truss Ca two-force
member EdlrgkMlaMgsgát; b¤kMlaMgTajtamG½kS. sMrab; truss TMrsamBaØEdlrgbnÞúkdUcbgðajkñúg
1 esckþIepþIm

2. NPIC
rUb Ggát;xagelICaGgát;rgkarsgát; ehIyGgát;xageRkamCaGgát;rgkarTaj. Ggát;RTnugGacCaGgát;
rgkarTaj b¤rgkarsgát; GaRs½yeTAelITItaMg/ TistMruy nigTItaMgrbs;bnÞúk.
RbePTepSgeTotrbs;Ggát;RtUv)anbgðajCamYynwg rigid frame enAkñúgrUbTI 1>2. Ggát;rbs;
eRKagenHRtUv)antP¢ab;y:agrwgedayTwkbnSar nwgGacsnμt;CaeRKOgbgÁúMCab;. enARtg;TMrGgát;RtUv)an
pSarP¢ab;eTAnwgbnÞHctuekaNEdlP¢ab;edayb‘ULúgeTAnwgRKwHebtug. edaydak;eRKagenHRsb²Kña ehIy
P¢ab;BYkvaedayGgát;bEnßm EdlbnÞab;mkRtUv)anRKbedaysMPar³dMbUl nigbiT)aMgedaysMPar³CBa¢aMg
edIm,IbegáIt)anCaRbB½n§sMNg;TUeTA. karlMGitsMxan;minRtUv)anerobrab;eT b:uEnþGaKarBaNiC¢kmμtUc²
RtUv)ansagsg;RbePTEbbenH. karKNnaeRKOgbgÁúM nigkarviPaKéneRKagnImYy²rbs;RbB½n§cab;epþIm
CamYynwgeRKagkñúgbøg;dUcbgðajenAkñúgrUbTI 1>2 b. cMNaMfaTMrRtUv)anbgðajCa hinges (pins) minEmn
TMrbgáb;. RbsinebIeCIgtagGacmanlT§PaBrgmuMrgVilsþÜcesþIg b¤RbsinebIkartP¢ab; flexible RKb;RKan;
edIm,IGnuBaØateGaymanmuMrgVil eKcat;TukTMrCa pinned. karsnμt;enAkñúgviFITUeTAénkarviPaKeRKOgbgÁúM
KWkMhYcRTg;RTaymantMéltUc Edlmann½yfamMurgVld¾tictYcrbs;TMrGaceFVIeGayTMrmanlkçN³CatMN
i
pinned )an.
enAeBlEdleKTTYl)annUvragFrNImaRtrbs;eRKag niglkçxNÐTMrehIy eKGackMNt;kardak;
bnÞúk)an. karkMNt;bnÞúkenHTak;TgnwgkarEckrMElkbnÞúksrubTaMgGs;eTAeRKagnImYy². RbsinebI
eRKagEdlBicarNargnUvbnÞúkdMbUlBRgayesμI enaHeRKagnImYy²EdlTTYlnUvcMENkrbs;bnÞúkenHnwg
manTMrg;CabnÞúkBRgayesμIEdlmanlkçN³CabnÞat;dUcbgðajenAkñúgrUbTI 1>2 b.
sMrab;kardak;bnÞúkEdlbgðajenAkñúgrUbTI 1>2 b/ eRKagnwgxUcRTg;RTaydUcbgðajenAkñúgeday
ExSdac;. Ggát;nImYy²rbs;eRKagRtUv)ancat;cMNat;fñak;edayGaRs½yeTAnwgRbePTénkareFVIkarEdl
sMEdgedayrUbragEdlxUcRTg;RTay. Ggát;edk AB nig BC rgnUvkarBt; (bending or flexure)
EdleKehAfaFñwm (beam). Ggát;bBaÄr BD EdlrgnUv couple EdlbBa¢ÚnBIFñwmnImYy² ¬b:uEnþsMrab;
eRKagsIuemRTIdUcbgðaj vamantMéldUcKña TisedApÞúyKña¦ dUcenHeKGacecal couple enH)an. dUcenH
2 Introduction

3. T.chhay
Ggát; BD rgEtkMlaMgsgát;tamG½kSEdl)anBIbnÞúkbBaÄr. enAkñúgsMNg; Ggát;rgkarsgát;bBaÄrdUcGVI
Edl)anerobrab;RtUv)aneKehAfassr (column). cMENkGgát;bBaÄrBIrepSgeTot AE nig CF min
EmnRtwmEtRTnUvkMlaMgsgát;tamG½kSb:ueNÑaHeT EfmTaMgRtUvTb;Tl;nwgkarBt;EdlmantMélFMeTotpg.
Ggát;EbbenHRtUv)aneKehAfa beam-column. Cak;Esþg RKb;Ggát;TaMgGs;eTaHCaRtUv)ancat;cMNat;
fñak;CaFñwm b¤ssrk¾eday k¾vaenAEtrgnUgbnÞúktamG½kS nigkarBt; b:uEnþenAkñúgkrNICaeRcInT§iBlmYy
mantMéltUcEdlGacecal)an.
bEnßmBIelIRbePTGgát;Edl)anBN’naxagelI esovePAenHnwgerobrab;BIkarKNnakartP¢ab; nig
Ggát;BiessdUcteTA³ composite beam, composite column nig plate girder.
1>2> bnÞúk Loads
kMlaMg (force) EdlmanGMeBIelIeRKOgbgÁúMRtUv)aneKehAfa bnÞúk (load). bnÞúkRtUv)anEckecj
CaBIrRbePTFM²KW³ bnÞúkefr (dead load) nigbnÞúkGefr (live load). bnÞúkefrCabnÞúkEdlsßitenACa
GciéRnþy_EdlrYmmanTMgn;rbs;eRKOgbgÁúMxøÜnÉg EdleKeGayeQμaHfabnÞak;pÞal;xøÜn (self-weight).
bEnßmBIelI self-weight, dead load enAkñúgGaKarrYmmanTMgn;rbs; nonstructural component Edl
3 esckþIepþIm

4. NPIC
mandUcCa floor covering, partition nig suspended ceilings ¬CamYynwgRbB½n§GKÁisnI/ sMPar³
emkanic nigRbB½n§Twk¦. RKb;bnÞúkEdl)anerobrab;CabnÞúkEdlTak;TgeTAnwgTMnajEpndIehIyRtUv)an
eKehAfa gravity loads. bnÞúkGefrEdlGacCa gravity load CabnÞúkEdlminenAsßitefrdUcbnÞúkefr.
vaGac b¤minGacmanGMeBIelIeRKOgbgÁúMRKb;eBl ehIyTItaMgrbs;vak¾minCab;lab;Edr. bnÞúkGefrrYmman
eRKOgsgðarwm sMPar³ GñkEdlrs;enAelIGaKar. CaTUeTAeKminGackMNt;GaMgtg;sIuetrbs; live
load )anCak;lak;dUc dead load eT ehIyvaRtUv)aneK)a:n;sμan. kñúgkrNICaeRcIn eKGegátGgát;eRKOg
bgÁúMsMrab;TItaMgepSg²rbs; live load EdlkareFVIEbbenHeKnwgemIlrMlgBIlkçxNÐ)ak;d¾eRKaHfñak;eT.
RbsinebIeKGnuvtþ live load mkelIeRKOgbgÁúMyWt² edaymindkecj nigdak;eLIgvijsarcuH
sareLIg enaHeKviPaKeRKOgbgÁúMCalkçN³sþaTic. RbsinebIeKGnuvtþbnÞúkelOn dUckñúgkrNIeRKOgbgÁúM
RT]bkrN_sÞÚccl½t eKRtUvKitbBa©ÚlT§iBlTgÁic. RbsinebIbnÞúkRtUv)andak; nigdkcuHeLIg²eRcIndg
kñúgmYyCIvitrbs;eRKOgbgÁúM fatigue stress nwgkøayCabBaðaEdlRtUvvykmksikSa. bnÞúkTgÁicekItman
cMeBaHGaKartictYc dUcCaGaKar]sSahkmμ cMENkÉ fatigue load KWkMrekItmanNas; eRBaHmunnwg
fatigue køayCabBaðavavdþénkardak;bnÞúkrab;Ban;dg. edaymUlehtuenH RKb;lkçxNÐbnÞúkTaMgGs;Edl
manenAkñúgesovePAenHRtUv)anKitCabnÞúksþaTic ehIyeKminBicarNaBI fatigue eT.
xül;bk;xÞb; nigbWtenAelIépÞxageRkArbs;GaKar edaysarFmμCatiminzitefrrbs;va eKcat;Tuk
xül;kñúgCMBUkbnÞúkGefr. b:uEnþedaysarkarKNnabnÞúkxül;manlkçN³sμúKsμaj eKcat;TukvakñúgCMBUk
dac;edayELk. edaysar lateral load manT§iBly:agxøaMgcMeBaHGaKarx<s;² dUcenHxül;manlkçN³
minsMxan;cMeBaHGaKarTab²eT b:uEnþ uplift énRbB½n§dMbUlRsalGacmaneRKaHfñak;. eTaHbICaxül;man
vtþmanRKb;eBlk¾eday k¾eKminBicarNavaCajwkjykñúgkarKNnaEdr ehIyeKmincat;TukvaCa fatigue
load eT.
bnÞúkrBa¢ÜydICaCMBUkBiessmYyeTotEdleKcaM)ac;BicarNaBIvasMrab;EtTItaMgPUmisaRsþNaEdl
ekItmanrBa¢ÜydIb:ueNÑaH. karviPaKeRKOgbgÁúMénT§iBlrbs;rBa¢ÜydITamTarkarviPaKén structure’s
response eTAnwgclnarbs;dIEdlbegáIteLIgedayrBa¢ÜydI. eBlxøHeKeRbIviFIEdlgayRsYl EdlT§i-
BlrBa¢ÜydIRtUv)an simulate edayRbBn½§kMlaMgedk dUcCasMBaFxül; edaydak;eGaymanGMeBItamCan;
nImYy²rbs;GaKar.
RBwlCaRbePTbnÞúkGefrmYyeTotEdlRtUvKitkñgCMBUkdac;edayELk. RBwlGacKrCaBMnUk.
ú
4 Introduction

5. T.chhay
bnÞúkGefrepSgeTotk¾RtUv)ancat;TukkñúgCMBUkdac;edayELkEdr dUcCasMBaF hydeostatic
nigsMBaFdI.
1>3> Building Codes
GaKarRtUv)anKNna nigsagsg;edayGaRs½yelIGVIEdlmanEcgenAkñúg building code EdlCa
Éksarc,ab;EdlmantMrUvkarTak;TgeTAnwgsuvtßiPaBeRKOgbgÁúM suvtßiPaBelIGKÁIP½y karerobcMRbB½n§Twk
karerobcMRbB½n§xül; nigkarsMrYldl;CnBikar. Building code min)anpþl;nUvlMnaMKNnaeT b:uEnþva
kMNt;nUvtMrUvkarkñúgkarKNna. lkçN³sMxan;sMrab;visVkreRKOgbgÁúMKWbBaØtþBIbnÞúkGefrGb,brmasMrab;
GKar.
bc©úb,nñ eKman building code mYyEdlGacsMrYldl;kargarrbs;visVkrEdlKNnaeRKOgbgÁúM
TaMgenAshrdæGaemric k¾dUcbNþaRbeTsepSg²KW International Building Code.
1>4> Design Specifications
pÞúyBI building code, design specification pþl;nUvkarENnaMlMGitsMrab;karKNnaGgát;
eRKOgbgÁúM nigkartP¢ab;rbs;va. Design Specification tMNageGaykarGnuvtþvisVkmμd¾l¥EdlQrelI
karsikSaRsavRCavcugeRkaybMput. vaRtUv)anEksMrYl nigeFVIeGaykan;EtRbesIreLIgtamxYb. dUcKñanwg
building code Edr design specification RtUv)ansresreLIgkñúgTMrg;c,ab;edayGgÁkarEdlminrkpl
cMeNj.
Specification EdlGñkKNnaeRKOgbgÁúMEdlcab;GarmμN_eRcInKW specification Edle)aHpSay
edayGgÁkardUcxageRkam³
!> American Institute of Steel Construction (AISC): Specification enHpþl;eGay
sMrab;KNnasMNg;éneRKOgbgÁúMEdk nigkartP¢ab;rbs;va. vaCa Specification cMbgEdl
ykcitþTukdak;edayesovePAenH (AISC, 1993).
@> American Association of State Highway and Transportation Officials (AASHTO):
Specification enHRKbdNþb;elIkarKNnas<an highway nigeRKOgbgÁúMTak;TgepSgeTot.
vapþl;nUvRKb;sMPar³TaMgGs;EdleRbICaTUeTAsMrab;s<anEdlmandUcCa Edk ebtugBRgwgeday
Edk nigeQI (AASHTO, 1992, 1994).
5 esckþIepþIm

6. NPIC
#> American Railway Engineering Association (AREA): ÉksarenHRKbdNþb;elIkar
KNnas<ansMrab;rfePøIg nigeRKOgbgÁúMEdlTak;Tg (AREA, 1992).
$> American Iron and Steel Institute (AISI): specification enHedaHRsayCamYynwg cold-
formed steel Edlmanerobrab;enAkñúgEpñk 1>6 kñúgesovePAenH (AISI, 1996).
1>5> eRKOgbgÁúMGMBIEdk Structural Steel
EdkRtUv)aneRbIR)as;dMbUgsMrab;CasMPar³tUc²taMgBIRbEhl 4000qñaMmunRKisþskraC
(Murphy, 1957). sMPar³enHmanTMrg;Ca wrought iron EdlplitedaykardutEr:EdkenAkñúgePøIg.
enAkñúgGMLúg cugstvtSr_TI 18 nigedImstvtSr_TI 19 cast iron nig wrought iron
RtUv)aneRbIsMrab;sMNg;s<an. Edk (steel) CasMelah³én iron nigkarbUn. Edkmansar³FatuminsuT§
nigkabUnticCag cast iron EdlRtUv)aneRbIsMrab;sMNg;Fn;F¶n;dMbUgkñúgstvtSr_TI 19.
CamYynwgkarmkdl;énkarEkERbrbs; Bessemer enAkñúgqñaM 1855 Edkcab;epþImCMnYs wrought iron
nig cast iron kñúgsMNg;.
lkçN³rbs;EdkEdlvisVkreRKOgbgÁúMcab;GarmμN_xøaMgCageKKWdüaRkaménlT§plEdkTaj. Rb
sinebIsMNakKMrUBiesaFn_rgkMlaMgtamG½kS P dUcbgðajenAkñúgrUbTI 1>3 a enaHkugRtaMg nig strain
GacRtUv)ankMNt;dUcxageRkam³
f =
P
A
nig ε = ΔLL
Edl f = kugRtaMgkMlaMgTajtamG½kS
A = RkLaépÞmuxkat;
ε = strain tamG½kS
L = RbEvgrbs;sMNakKMrU
ΔL = kMhUcRTg;RTay
RbsinebIeKbegáInbnÞúkBIsUnüeTAdl;cMnucdac; (fracture) ¬kugRtaMg nig strain RtUv)anKNna
tamCMhannImYy² ¦ stress-strain curve RtUv)anbgðajenAkñúgrUbTI 1>3 b. ExSekagenHCarbs;RbePT
EdksVit (ductile, mild or steel) . TMnak;TMngrvagkugRtaMg nig strain manlkçN³CabnÞat;BIcMnucsUnü
rhUtdl;EdnkMNt;smamaRt (proportional limit) EdlkñúgcenøaHenH sMPar³eKarBtamc,ab;h‘Uk
(Hook’s law). bnÞab;mkvaeTAdl;cMnuc yield xagelIy:agelOnrYcFøak;mkcMnuc yield xageRkam.
6 Introduction

7. T.chhay
bnÞab;BI enaHkugRtaMgenArkSatMélefr eTaHbICa strain enAEtbnþekIneLIgk¾eday. enARtg;tMNak;
kalénkardak;bnÞúkenH sMNakKMrUBiesaFn_enAEtbnþlUtEvg eTaHbICabnÞúkminRtUv)anekIneLIgk¾eday
¬EtbnÞúkminRtUv)andkeT¦. tMbn;kugRtaMgefrenHRtUv)aneKehAfatMbn;)aøsÞic (plastic range or yield
plateau). enARtg; strain RbEhl 12dgén strain enAtMbn; yield, strain hardening cab;epþIm
ehIyeKRtUvkarbnÞúkbEnßm ¬nigkugRtaMg¦ edIm,IeFVIeGaymansac;lUtbEnßm ¬nig strain¦. eRkayeBl
vaeTAdl;cMnuckugRtaMgGtibrma sMNakKMrUcab;epþIm neck down EdleFVIeGaykugRtaMgcab;epþImfycuH
Et strain enAEtbnþekIneLIgdEdl ehIy fracture ekIteLIg.
eTaHbICamuxkat;RtUv)ankat;bnßykñúgGMLúgeBldak;bnÞúkk¾eday (poisson effect) k¾eKenA Et
eRbIRkLaépÞmuxkat;edImedIm,IKNnakugRtaMgTaMgGs;. kugRtaMgEdl)anKNnatamviFIenHRtUv)aneK
sÁal;faCa engineering stress. RbsinebIeKeRbIRbEvgedImedIm,IKNna strain enaHvaRtUv)aneKehAfa
engineering strain.
7 esckþIepþIm

8. NPIC
EdkEdlRtUv)anBiesaFedIm,I)andüaRkamdUckñúgrUbTI 1>3 b Ca ductile eRBaHvamanlT§PaBrg
kMhUcRTg;RTayFMmunnwg fracture. PaBsVit (ductility) Gacvas;)anedaysac;lUt (elongation) Edl
kMNt;eday
L f − Lo
e=
Lo
×100 (1>1)
Edl e = sac;lUt ¬KitCaPaKry¦
L f = RbEvgrbs;sMNakKMrUenAeBldac;
Lo = RbEvgedIm
EdnkMNt;eGLasÞic (elastic limit) rbs;sMPar³CakugRtaMgEdlsßitenAcenøaHEdnsmamaRt nig
cMnuc yeild xagelI. rhUtdl;kugRtaMgenH eKGacdkbnÞúkBIsMNakKMrUedayminmankMhUcRTg;RTay.
kardkbnÞúknwgsßitenAtamKnøgénkardak;bnÞúk ehIyvaminman permanent strain eT. EpñkenHrbs;
stress-strain diagram RtUv)aneKeGay eQμaHfa EdneGLasÞic (elastic rage). eRkABI elastic limit
kardkbnÞúknwgsßitenAelIExSRtg;RsbeTAnwgExSénkardak;bnÞúk ehIyvanwgman permanent
strain. ]TahrN_ RbsinebIeKdkbnÞúkRtg;cMnuc A kñúgrUbTI 1>3 b kardkbnÞúknwgsßitenAelIExS
AB Edlpþl;nUv permanent strain OB .
rUbTI 1>4 bgðajBIkMENd¾l¥rbs; stress-strain curve. Proportional limit, elastic limit,
upper nig lower yield point KWsßitenAelIcMnucEtmYyEdleKehAfa yield point EdlkMNt;edaykug
RtaMg Fy . cMnucmYyeTotEdlvisVkreRKOgbgÁúMcab;GarmμN_KWkugRtaMgGtibrma EdleKeGayeQμaHfa
ultimate tensile strength Fu . rUbragrbs;ExSekagenHCaKMrUsMrab; mild structural steel TaMgGs;
EdlvaxusKñaBImYyeTAmYyedaytMél Fy nig Fu . pleFobkugRtaMgelI strain kñúgEdkeGLasÞic
8 Introduction

9. T.chhay
RtUv)ankMNt;eday E EdleKehAfa young’s modulus or modulus of elasticity. E mantMé;lesμI
29000 ksi ≈ 2 ⋅ 10 5 MPa sMrab;RKb;eRKOgbgÁúMEdkTaMgGs;.
rUbTI 1>5 bgðajBIRbePT stress-strain curve sMrab; high-strength steels EdlmanPaBsVit
tUcCag mild steels. eTaHbIvamanEpñk linear elastic nig tensile strength k¾eday Etvaminman yield
point b¤ yield plateau eT. edIm,IeRbI higher strength steel enHeGaydUcnwgkareRbIR)as; ductile steel
eKRtUvkartMélkugRtaMg Fy dUcenHeKGaceRbIdMeNIrkar nigrUbmnþdUcKñasMrab;RKb;RbePTEdkTaMgGs;.
dUcEdl)anbgðajBImun enAeBlEdlEdkrgkugRtaMgeRkABI elastic limit ehIybnÞab;mkRtUv)andkbnÞúk
vanwgsßitenAelIKnøgExSRsbnwgKnøgdak;bnÞúk ehIyvamineTAdl;cMnuc strain esμIsUnüeT. dUcenHvaman
residual strain b¤ permanent set eRkayeBldkbnÞúk. yield stress sMrab;EdkCamYynwgRbePT
stress-strain curve EdlbgðajenAkñúgrUbTI 1>5 RtUv)aneKehAfa yield strength RtUv)ankMNt;Cakug
RtaMgRtg;cMnucénkardkbnÞúkEdlRtUvnwg permanent strain énbrimaNkMNt;NamYy. eKeRCIserIsyk
strain 0.002 ehIyviFIénkarkMNt; yield strength enHRtUv)aneKehAfa 0.2% offset method. dUc
Edl)anerobrab;BImun CaTUeTAeKRtUvkarlkçN³BIrsMrab; structural strength design KW Fy nig Fu
edayminKitBIrUbragrbs; stress-strain curve nigminKitBIrebobEdlTTYl)an Fy . sMrab;mUlehtuenH
eKeRbItYTUeTA yield stress ehIyvaGacmann½yCa yield point b¤ yield strength.
lkçN³epSg²rbs;eRKOgbgÁúMEdkEdlrYbbBa¢ÚlTaMg strength nig ductility RtUv)ankMNt; eday
smasFatuKImI (chemical composition). Edk (steel) CasMelah³ EdlFatupSMcMbgrbs;vaCa iron.
sarFatupSMrbs;eRKOgbgÁúMTaMgGs; ¬eTaHCakñúgbrimaNtictYc¦ KWkabUn EdlcUlrYmkñúgkarbegáIn
9 esckþIepþIm

10. NPIC
strength b:uEnþkat;bnßy ductility. karekIneLIgPaKrykabUnbegáIn strength Etkat;bnßy ductility
EdleFVIeGaykarpSarmankarBi)ak. sarFatud¾éTeTotrbs; grade xøHrbs;EdlrYmmans<an; (copper),
manganese, nickel, chromium, molybdenum nig silicon. eRKOgbgÁúMEdkRtUv)anerobcMCaRkum
GaRs½yeTAnwgsarFatupSMrbs;vadUcxageRkam³
!> Plain carbon steel: EdlPaKeRcInCa iron nigkabUnticCag 1%
@> Low-alloy steel: man iron nigkabUn EdlrYmpSMCamYynwgsarFatuepSgeTot ¬CaTUeTAtic
Cag 5% ¦. sarFatubEnßmKWedIm,IbegáInersIusþg; Etvanwgkat;bnßyPaBsVit.
#> High-alloy or specialty steel: mansarFatupSMRsedogKñanwg low-ally steel Edr Etman
sarFatubEnßmeRcInPaKryCag. EdkenHmanersIusþg;FMCag plain carbon steel nigman
KuNPaBBiessdUcCakarBarERcH.
Grade rbs; structural steel RtUv)ankMNt;eday American Society for testing and
Material (ASTM). GgÁkarenHbegáItbTdæanedIm,IkMNt;sMPar³eTAtamsarFatupSM lkçN³ nigkareFVI
karrbs;va (ASTM, 1996a).`EdkeRKOgbgÁúMEdleKcUlcitþeRbIsBVéf¶Ca mild steel EdlsMKal;Ca
ASTM A36 b¤sresry:agxøI A36 . vaman stress-strain curve dUcbgðajenAkñúgrUbTI 1>3 b nig 1>4
ehIymanlkçN³rgkarTajdUcxageRkam³
Yield stress: Fy = 36 Ksi ≈ 250MPa
Tensile strength: Fu = 58ksi ≈ 400 MPa eTA 80ksi ≈ 550MPa
Edk A36 RtUv)ancat;fñak;Ca plain carbon steel ehIyvamansarFatupSM ¬eRkABI iron¦dUcxageRkam³
Carbon: 0.26% ¬Gtibrma¦
Phosphorous: 0.04% ¬Gtibrma¦
Sulfur: 0.05% ¬Gtibrma¦
PaKryenHCatMélRbhak;RbEhl tMélCak;EsþgGaRs½ynwgTMrg;énkarplitEdk. Edk A36 Ca
ductile steel Edkmansac;lUt (elongation) EdlkMNt;edaysmIkar 1.1 KW 20% edayQrelIRbEvg
edIm Lo = 8in. ≈ 200mm .
eKRtUvplitEdk A36 edayeKarBtambTdæanrbs; ASTM. tMél yield strength nig tensile
strength Edl)anbgðajCatMrUvkarGb,brma vaGacFMCag. Tensile strength RtUv)aneGayedaycenøaH
tMélmYyeRBaHlkçN³enHminGacTTYl)any:agsuRkitdUc yield strength eT.
10 Introduction

11. T.chhay
CaTUeTA EdkEdlman yield stress FMCag 36ksi RtUv)anKitCa high-strength steel. High-
strength steel EdleKniymeRbIeRcInCaRbePTEdkEdlman yield strength 50ksi ≈ 345 MPa nigman
tensile strength 65ksi ≈ 450 MPa b¤ 70ksi ≈ 480 MPa ehIyeKk¾manEdkEdlman yield strength
100 ksi ≈ 690 MPa . Ca]TahrN_ ASTM A242 Ca low-alloy, corrosion resistant steel EdlGac
man yield strength 42ksi ≈ 290MPa / 46ksi ≈ 320 MPa nig 50ksi ≈ 345MPa CamYynwg tensile
strength EdlRtUvKña 63ksi ≈ 435 MPa / 67 ksi ≈ 460 MPa nig 70 ksi ≈ 480 MPa . ehIysmas-
FaturYmpSMKImIrbs;vamandUcxageRkam³
Carbon: 0.15% ¬Gtibrma¦
Manganese 1.00% ¬Gtibrma¦
Phosphorus: 0.15% ¬Gtibrma¦
Sulfur: 0.05% ¬Gtibrma¦
Copper: 0.20% ¬Gtibrma¦
Edk A242 minEmn ductile dUc A36 . sac;lUtEdlQrelIRbEvgedIm 8in. ≈ 200mm KW 18% ebI
eRbobeFobCamYysac;lUtrbs; A36 KW 20% .
1>6> rUbragmuxkat;bTdæan Standard Cross-sectional Shapes
eKalbMNgcMbgkñúgkarKNnaeRKOgbgÁúMEdkKWkareRCIserIsmuxkat;EdlsmRsbsMrab;Ggát;nI-
mYy². CaTUeTA kareRCIserIsenHtMrUveGayeRCIserIsrUbragmuxkat;bTdæanEdleRbIR)as;y:agTUlMTUlay
CagkartMrUveGayplitrUbragEdlmanxñat niglkçN³Biess. kareRCIserIsrUbragEdlmanRsab; (off-
the shelf) CaCMerIsEdlmanlkçN³esdæikc©Cag eTaHbICavaeRbIsMPar³eRcInCagbnþick¾edaykþI. RbePT
énrUbragbTdæanEdlFMCageKRtUv)anplitedaykarhUtekþA (hot-rolling). enAkñúgdMeNIrkarplitEdl
eFVIeLIgenAkñúgeragcRkplitEdk (mill) EdkEdlrlayEdl)anBILsøEdkRtUv)ancak;cUleTAkñúgRbB½n§
Bum<EdlCab; edayTukeGayEdkeLIgrwg b:uEnþeKminGnuBaØateGayvaRtCak;eBjeljeT. EdkekþAqøg
kat; roller Caes‘rI EdlKabeGayeTACarUbragEdlcg;)an. karhUtEdkkñúgeBlEdlvaenAekþAGnuBaØat
vaxUcrUbragedaymin)at;bg; ductility rbs;va dUckrNIhUtRtCak;. kñúgGMLúgeBlhUt Ggát;EdklUt
RbEvg ehIyRtUv)ankat;tamRbEvgbTdæan EdlCaTUeTAmanRbEvgGtibrmaBI 65 ft ≈ 20m eTA
75 ft ≈ 23m ehIyEdlvaRtUv)ankat;CabnþbnÞab;eTAtamRbEvgrbs;eRKOgbgÁúMenAeragCag.
11 esckþIepþIm

12. NPIC
muxkat;xøHén hot-rolled shape EdlRtUv)aneRbICaTUeTARtUv)anbgðajenAkñúgrUbTI 1>6. xñat
nigkMNt;sMKal;rbs;rUbragbTdæanRtUv)ankMNt;enAkñúg ASTM standard (ASTM, 1996b). W-shape
EdleKehA)anfa rUbragsøabFM (wide flange shape) EdlpSMeLIgedaysøabBIrEdlEjkedayRTnug
mYy. rUbragenHmanG½kSsIuemRTIBIr. karkMNt;sMKal;CaKMrUrbs;vaKW W 18 × 50 Edl W bgðajBI
RbePTrUbrag/ 18 Ca nominal depth EdlRsbeTAnwgRTnug nig 50 CaTMgn;rbs;EdkkñúgmYyÉktþa
RbEvg. W-shape én nominal size TaMgGs;RtUv)andak;CaRkumEdlmankMBs;BIsøabxagkñúgeTAsøab
xagkñúgdUcKña b:uEnþmankMras;søabxusKña.
American Standard b¤ S-shape KWRsedogKñaeTAnwg W-shape edaymansøabBIrRsbKña
RTnugmYy nigmanG½kSsIuemRTIBIr. PaBxusKñarbs;vaKWsmamaRtrbs;muxkat;³ søabrbs; W FMCagRTnug
Edlsøabrbs; S tUcCagRTnug. elIsBIenH épÞxagkñúg nigépÞxageRkArbs;søabén W-shape man
lkçN³RsbKña EtépÞxagkñúgénsøabrbs; S-shape eTrEdlkMras;xagcugtUcCagkMras;enAEk,rRTnug.
kMNt;sMKalrbs; S-shape KW S18 × 70 Edl S bgðajBIRbePTrbs;rUbrag nigelxBIrtYCakMBs;
nigTMgn;kñúgmYyÉktþaRbEvg erogKña. rUbragenHRtUv)aneKehAfa I-beam.
12 Introduction

13. T.chhay
EdkEkg (angle shape) GacmaneCIgesμI b¤eCIgminesμI. karkMNt;sMKal;KMrUKW L × 6 × 6 × 3 4 b¤
L6 × 3 × 5 8 . elxTaMgbItYKW RbEvgeCIgTaMgBIrrbs;vaEdlvas;BIcugeTAEkgxageRkA nigkMras;rbs;va.
kñúgkrNIEdkEkgEdlmaneCIgminesμI eCIgEvgRtUv)ansresrmun. karkMNt;sMKalrbs;EdkEkgmin)an
R)ab;BITMgn;eT.
American Standard Channel b¤ C-shape mansøabBIr nigRTnugmYy ehIymanG½kSsIuemRTI
mYy. kMNt;sMKal;KMrUrbs;vaKW C9 × 20 . nimitþsBaØaenHKWRsedogKñanwg W- nig S-shape Edr Edl
manelxmYytYtMNageGaykMBs; nigmYytYeTottMNageGayTMgn;kñúgmYyÉktþaRbEvg. b:uEnþsMrab;
channel kMBs;manRbEvgCak;EsþgCag. épÞxagkñúgrbs;søabKWdUcKñanwg S-shape Edr. eKenAman
Miscellaneous Channel EdlCa]TahrN_ MC10 × 25 KWRsedogKñanwg American Standard
Channel Edr.
Structural Tee RtUv)anplitedaykat; W-, M- b¤ S-shape Rtg;kMBs;Bak;kNþal. eBlxøHeK
ehArUbragenHfa split-tee. buBVbTénnimitþsBaØarbs;rUbragenHKW WT, MT b¤ ST GaRs½yeTAelI
rUbragedImrbs;vamuneBlkat;. ]TahrN_ WT18 × 115 man nominal depth 18in. nigmanTMgn;
115lb / ft ehIyvaRtUv)ankat;ecjBI WT 36 × 230 . dUcKñasMrab; ST- nig MT-shape.
edaymin)anbgðajkúñgrUbTI 1>6 eKenAman hot-rolled shapes EdlmanlkçN³RsedogeTAnwg
W-shape EdrKW³ HP- nig M-shapes. eKeRbI HP shape sMrab;ssrRKwH EdlvamanépÞsøabRsbKña
nigmanTTwgesμInwgkMBs; ehIykMras;søabdUcKñanwgkMras;RTnug. GkSr M tMNageGay Miscellaneous
¬epSg²¦ EdlrUbragenHminRtUvKñanwgRbePTrUbragén W, HP b¤ S eT. TaMg M- nig HP-shape
RtUv)ansMKal;kñúgTMrg;dUcKñanwg W-shape Edr ]TahrN_ M 14 × 18 nig HP14 × 117 .
rUbragEdlRtUv)aneKeRbICajwkjab;Edr RtUv)anbgðajenAkñúgrUbTI 1>7. Bar Gacmanmuxkat;
mUl kaer: nigctuekaNEkg. RbsinebITTwgrbs;muxkat;ctuekaNEkgmanRbEvgtUcCag 8in. ≈ 20cm
eKcat;TukrUbragenHCa bar ehIyvaRtUv)ansMKal;edayTTwgmunkMras; ( 8 × 3 4 ) EtpÞúymkvijvaRtUv)an
cat;TukCa plate ehIykMNt;sMKal;rbs;vaRtUv)annaMmuxedaykMras; munTTwg ( 1 2 × 10 ). Bar nig
plate RtUv)anpliteday hot-rolling.
13 esckþIepþIm

14. NPIC
rUbTI 1>7 k¾bgðajBImuxkat;RbehagEdr EdlGacplitBI plate EdlRtUv)anBt;eTACarUbrag
Edlcg;)anehIypSartamefñr b¤eday hot-working edIm,IplitrUbragEdlKμanefñr. rUbragenHRtUv)an
kt;sMKal;eday HSS sMrab;muxkat;EdkRbehag. muxkat;RbehagrYmman TIbmUl nigTIbRCug Edlman
rUbragkaer: nigctuekaN.
eKenAmanrUbragepSg²eTot b:uEnþeyIgelIkykEtrUbragEdleKniymeRbICaTUeTAmkbgðaj
b:ueNÑaH. kñúgkrNICaeRcIn rUbragbTdæanmYynwgbMeBjtMrUvkarkarKNna. RbsinvaminmanrUbragbTdæan
EdlRtUvnwgkarKNnaeT eKcaM)ac;eFVI built-up section dUcbgðajenAkñúgrUbTI 1>8. eBlxøH standard
shape RtUv)anbEnßmeday cross-sectional element dUckrNIEdleKpSar cover plate P¢ab;eTAnwgsøab
mYy b¤søabTaMgBIrrbs; W-shape. kareFVI built-up section CaviFId¾manRbsiT§PaBkñúgkarbegáIn
lT§PaBRTRTg;rbs; standard shape. eBlxøHeKRtUveRbI built-up shape edaysarKμan standard
rolled shape NaEdlmuxkat;rbs;vamanRkLaépÞ b¤m:Um:g;niclPaBFMlμm. enAkñúgkrNIEbbenH eKeRbI
plate girder EdlGacmanrUbragCa I-shaped section EdlmansøabBIr nigRTnugmYy b¤muxkat;RbGb;
EdlmansøabBIr nigRTnugBIr. eKGacpSarFatupSMbBa©ÚlKña edayrcnaedIm,ITTYl)annUvlkçN³Edl
cg;)an. eKGacbegáIt built-up shape edayP¢ab; standard rolled shape BIr b¤eRcInbBa©ÚlKña. bnSM
rUbragEdleRbICaTUeTAKWEdkEkgDubEdlRtUv)andak;xñgTl;xñg ehIyRtUv)anP¢ab;tamcenøaHénRbEvgrbs;
va.
14 Introduction

15. T.chhay
RbePTepSgeTotrbs;EdksMrab;eRKOgbgÁúMKW cold-formed steel. Structural steel RbePTenH
RtUv)anbegáIteLIgedaykarBt;snøwkbnÞHEdkesþIgedaymineRbIkMedA. muxkat;KMrURtUv)anbgðajenAkñúgrUb
TI 1>9. Cold-formed shape RtUv)aneRbIsMrab;RTTMgn;Rsalb:ueNÑaH. Cold-working nwgbegáIn yield
point b:uEnþvanwgkat;bnßyPaBsVitrbs;Edk nigeRkamlkçxNÐCak;EsþgeKGaceRbIvakñúgkarKNna (AISI,
1993). KuNsm,tþirbs;vaKWrUbragrbs;vagayRsYlkñgkarbegáIt. edaysarmuxkat;rbs;vaesþIg
ú
instability CaktþacMbgkñúgkarKNna cold-formed structure.
15 esckþIepþIm