Your SlideShare is downloading. ×
1.introduction
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

1.introduction

240
views

Published on


0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
240
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
0
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 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