DesignprovisionsofBS5950part1

Prepared:Ismael .S Lead:Tridibesh Indu Project:SOGTMalaysia SAMSUNGENGINEERINGINDIA

ContentsIntroduction General Limitstatedesign Scope,References&Definitions Generalprinciplesanddesignmethods Ultimatelimitstates Serviceabilitylimitstates Structuralsteel Boltsandwelds Tensionmembers Compressionmembers Memberssubjectedtobending Combinedmomentandaxialforce

Propertiesofmaterials &SectionProperties Designofstructural members

Continuousstructures Connections LoadingTests

Introduction

Objective: TostudyandpresenttheprovisionsofBS5950part1relatedtothedesignoftension members,compressionmembersandflexuralmembers

Scope: TheBS 5950 Part1 givesrecommendationsforthedesignofstructuralsteelworkusing Hotrolledsteelsections,Flats,Plates,Hotfinishedstructuralhollowsections,Coldformed structuralhollowsectionsinbuildingsandalliedstructures.

LimitstatedesignGeneralprinciple: Theaimofstructuraldesignshouldbetoprovide,astructurecapablefulfillingitsintended functionandsustainingthespecifiedloadsforitsintendedlifewithdueregardto economy. Appropriatepartialfactorsshouldbeappliedtoprovideadequatedegreesofreliabilityfor ultimatelimitstatesandserviceabilitylimitstates. 1.Ultimatelimitstates concerningthesafetyofthewholeorpartofthestructure.

Incheckingthestrengthofastructure,orofanypartofit,thefactoredloadsshouldbe appliedinthemostunfavorablerealisticcombinationforthepartoreffectunder consideration Theloadcarryingcapacityofeachmemberandconnection,should besuchthatthefactored loadswouldnotcausefailure.

LimitstatedesignLoadcombinations(ULS): Loadcombinations 1 2 Dead&Imposed loads(gravityloads) Deadload&Wind (WL)orEarthquake load(EL) Deadload,Imposed load&WLorEL 1.4 DL 1.4 DL+1.6 LL 1.0 DL+1.4 WL 1.4 DL+1.4 WL 1.4 DL+1.4 EL 1.2 DL+1.2 LL+1.2 WL 1.2 DL+1.2 LL+1.2 EL Incomb1,theNotionalhorizontalforce shouldbeapplied,takenasaminof0.5%of thefactoredverticaldeadandimposedloads Incomb2&3,thehorizontalcomponent ofthefactoredwindloadshouldnotbe takenaslessthan1.0%ofthefactored deadloadappliedhorizontally

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Asthespecifiedloadsfromoverheadtravellingcranesalreadyincludesignificanthorizontalloads, itisnotnecessarytoincludeverticalcraneloadswhencalculatingtheminimumwindload/ notionalhorizontalforces.

Limitstatedesign2.Serviceabilitylimitstates Deflection VibrationandOscillation Durability Loadcombinations 1 2 Dead&Imposed loads(gravityloads) Deadload&Wind (WL)orEarthquake load(EL) Deadload,Imposed load&WLorEL 1.0 DL 1.0 DL+1.0 LL 1.0 DL+1.0 WL 1.0 DL+1.0 EL 1.0 DL+1.0 LL+0.8 WL 1.0 DL+1.0 LL+0.8 EL Exceptionalsnowloads shouldnotbe includedintheimposedloadwhen checkingserviceability. IncaseofcombinedLL&WL,only80% ofthefullspecifiedvalueneedbe consideredwhencheckingserviceability correspondtolimitsbeyondwhichspecifiedservice criteriaarenolongermet.

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LimitstatedesignStabilityLimitState Staticequilibrium ResistancetoHorizontalForce Notionalhorizontalforce Toallowfortheeffectsofpracticalimperfectionssuchaslack ofverticality,allstructuresshould becapableofresistingnotionalhorizontalforces,takenasaminimumof0.5 %ofthefactored verticaldeadandimposedloadsappliedatthesamelevel. Thenotionalhorizontalforcesshouldbeassumedtoactinanyonedirectionatatimeand shouldbeappliedateachroofandfloorlevelortheirequivalent.Theyshouldbetakenasacting simultaneouslywiththefactoredverticaldeadandimposedloads (loadcombination1). Thenotionalhorizontalforcesshouldnotbeapplied whenconsideringoverturning&patternloads withhorizontalloads&temperatureeffects Thenotionalhorizontalforcesshouldnotbetakentocontribute tothenetreactionsatthe foundations. Sliding,OverturningorLiftoffitsseating. NotionalHorizontalforce&WLetc.

Limitstatedesign Swaystiffness Allstructuresshouldhavesufficientswaystiffness,sothattheverticalloadsactingwiththelateral displacementsofthestructuredonotinduceexcessivesecondary forcesormomentsinthe membersorconnections. Nonsway: Iftheswaymodeelasticcriticalloadfactorunderverticalload Where, cr > 10

cr =h/200 h isstoreyheight isdeflectionoftopofstoreyrelativetobottomofstoreydue tonotional horizontalforce

Swaysensitive:Secondaryforcesandmomentsshouldbeallowedbymultiplyingthesway effectsbythe amplificationfactorkamp. Where, kamp =cr/(1.15cr1.5) butkamp > 1.0

PropertiesofMaterial StructuralSteel Thedesignstrengthpy forcommonlyusedgradesandthicknessesofsteelisspecifiedinBS59502, AlternativelyfromTable9ofBS59501. Thedesignstrengthpy shouldbetakenas 1.0Ys butnotgreaterthanUs /1.2 Ys theminimumyieldstrength Us theminimumtensilestrength

PropertiesofMaterial StructuralBolts Strengthofbolts(MPa) Boltgrade 4.6 8.8 10.9 GeneralgradeHSFG toBS4395 < M24 > M27 Shearps 160 375 400 400 350 0.4Ub Bearingpbb 460 1000 1300 1000 900 1300 0.7(Ub+Yb) Tensionpt 240 560 700 590 515 700 0.7Ub but