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Chapter3Compositefloorwithsteelprofiled压型钢板压型钢板-混凝土组合楼板混凝土组合楼板ByProfessorShimingChenLectureNotesforPresentation2019Chapter3Compositefloorwit1OBJECTIVE/SCOPETodescribethedesignofone-wayspanningcompositeslabs,formedusingprofiledsteelsheetingandaconcretetopping,includingconsiderationofultimateandserviceabilitylimitstatedesignforbuildingstructures.压型钢板、压型钢板分类压型钢板-混凝土组合楼板应用范围设计方法构造OBJECTIVE/SCOPE23.1Introduction压型钢板-混凝土组合楼板是指将压型钢板与混凝土通过某种构造措施组合成整体而共同工作的受力构件。Compositeflooringsystemconsistsofacold-formed,profiledsteelsheetwhichacts,notonlyasthepermanentformworkforanin-situcastconcreteslab,butalsoasthetensilereinforcementTheessentialcompositeactionbetweenthesteeldeckandtheconcreteslabisprovidedbysomeformofinterlockingdevice,capableofresistinghorizontalshearandpreventingverticalseparationatthesteel/concreteinterface.3.1Introduction压型钢板-混凝土组合楼板是指3Compositeslabwithprofiledsteelsheetitprovidesaworkingplatformforconstruction.itactsasformworkfortheconcreteslab.itconstitutesbottomreinforcementfortheslab.Compositeslabwithprofileds4压型钢板组合楼板课件5ProfiledSteelsheeting(apatternofembossments)板面的齿槽与压痕可提供界面粘结力；界面的摩擦粘结等ProfiledSteelsheeting(apatt6Constructionstage:placetheprofiledsteelsheetingoverthesupportbeamsConstructionstage:placethe7Constructionstage:weldstudsthroughthesteelsheetingwithportableweldinggunConstructionstage:weldstuds8Constructionstage:placethelightsteelreinforcement/steelmeshConstructionstage:placethe9Constructionstage:castconcreteConstructionstage:castconcr10TypesofProfiledSheet压型钢板类型压型钢板类型Re-entranttypes闭口型压型钢板闭口型压型钢板TypesofProfiledSheet压型钢板类型11Trapezoidaltypes开口型压型钢板开口型压型钢板Trapezoidaltypes开口型压型钢板12Advantagesidentifiedasthefollows:Thesteeldeckactsaspermanentshutteringforthein-situcastconcreteslab,withaconsequentsavingintimeandlabor.It once in position,immediately provides aplatformtosupportconstructionloadsandasafe,sturdyworkingsurface.Itactsasthetensilereinforcement.Thesteeldeckgeometrycanresultinareductionoflaborabout30%intheamountofconcretefillrequired for the floor,significant reduction indeadweightloads.Advantagesidentifiedast133.2.DESIGNPRINCIPLES设计验算设计验算DesignSituations（设计工况）（设计工况）Twodistinctstructuralstatesmustbechecked:firstly,thetemporarystateofexecution,whenonlythesheetingresiststheappliedloads（constructionstage施工阶段）;secondly,thepermanentstate,aftertheconcreteisbondedtothesteelgivingcompositeaction（compositestage正常使用阶段）.Relevantlimitstatesandloadcasesareconsideredforbothdesignsituations.3.2.DESIGNPRINCIPLES设计验算14a)Steeldeckshuttering（施工阶段）Verificationsattheultimatelimitandserviceabilitylimitstatesarerequired,withrespecttothesafetyandserviceabilityofthesteeldeckactingasformworkforthewetconcrete.Theeffectsofanytemporarypropsusedduringexecution,mustbetakenintoaccountinthisdesignsituation.b)Compositeslabs（正常使用阶段）Verificationsattheultimatelimitandserviceabilitylimitstatesarerequired,withrespecttothesafetyandtheserviceabilityofthecompositeslabaftercompositebehaviourhascommencedandanypropshavebeenremoved.a)Steeldeckshuttering（施工阶段）15设设计计考考虑虑因因素素：Three major aspects identified forconsideration during the design of a compositeflooringdeck:Thesteeldeckitselfmustbesufficientlystrongandrigid to support the weight to wet concrete duringcasting-constructionstagebehavior.Thesteeldeckactingcompositelywiththehardenedconcrete,andspanningbetweenthesupportingsteelbeams,must support the imposed live loading-compositeslabaction.The steel beams,acting compositely with thehardenedconcretethroughthestudshearconnectorsmust support the imposed live loading-compositebeamaction.设计考虑因素：Threemajoraspects163.2Criteriaforthedesignofcompositefloors设计准则设计准则Indesign,itisnecessarytoensurethatthestrengthanddeflectionsbothduringconstruction(whentheconcreteisstillgreen)andinservice(whencompositeactionhasbeenachieved)aresatisfactory.Constructionstage:theprofiledsteeldeckalonewithstandstheweightofwetconcrete,workmanandequipment.Compositeslabstage:thehardenedconcreteslab,actingcompositelywiththeprofiledsteelsheet,spansbetweenthesupportingbeamsandcarriestheimposedliveloads3.2Criteriaforthedesign17KeypointsforConstructionstage-ProfiledsteelasshutteringInstallationofthesheetingiscarriedoutbylayingoneormorespanlengthsoverthesupportingbeams.Thesheetingbehavesasafoldedplatestructureand,forlowloadlevels,thebehaviorissimilartosimplebeambehavior.Athigherloadlevels,bucklingofthecomponentplatesmayoccur.Thepredictionofbucklingstressesonthecomponentplatescanbeachievedusingclassicalorenergymethods.KeypointsforConstructionst18Thesheetinghastohaveadequatebendingstrengthandstiffness.Thesectionpropertiesofprofiledsheetscanbecomputedbasedontheanalyticalmethodsprovidedbydesigncodes.Manufacturersprefertocarryoutloadtestsontheirproductstoassessfullcapacityandprovideload-spantablesappropriatetoeachprofile.Proppingcandramaticallyreducedeflections.Thesheetinghastohaveadequ19KeypointsforcompositestageThesteeldeckactsastensilereinforcementtotheslabandthedevelopmentofcompositeactiondependsentirelyuponadequatetransferenceofhorizontalshearforcesatthesteel/concreteinterface.Toevaluatetheshearbondresistanceattheinterfacebetweentheconcreteandtheprofileddeck,PorterandEkberg(1976)proposedatestingprogram(shear-bondtest)nowworldwideadoptedindeterminationoftheshearbondresistanceforcompositeslabs.Keypointsforcompositestage203.3BEHAVIORANDANALYSISSteeldeck（混凝土结硬前：压型钢板）Duringexecutionwhentheconcreteiswet,thesteeldeckaloneresiststheexteriorloads.Itsbehavioristhencomparabletothatofprofilesusedforroofdecking.Thesteeldeckissubjectedmainlytobendingandshear;compressionduetobendingmayariseineithertheflangesortheweb;shearoccursessentiallynearthesupports.3.3BEHAVIORANDANALYSISS21Oncetheconcretehashardenedthesteeldeckandconcretecombinetoformasinglestructuralunit,thecompositeslab.Behaviorofacompositeslabisanalogoustothatofaconventionalreinforcedconcreteslab.Thebondbetweenthesteeldeckandconcretemaynotbefullyeffectiveandlongitudinalslipmayoccurbeforethesteeldeckyields.Oncetheconcretehashardened22CompositeslabfailuremodetypesFailuretypeI:弯曲破坏(flexuralfailure)：FailuretypeII:纵向剪切破坏(longitudinalshearfailure,shear-bondfailure.)：FailuretypeIII:垂直剪切破坏(verticalshearfailure)Compositeslabfailuremodety23LoaddeflectionresponseofbrittleandductileslabsThebrittleorductilemodeoffailuredependsonthecharacteristicsofthesteel-concreteinterface.Loaddeflectionresponseofbr24ShearbondfailureBrittlebehaviorinwhichslipcausesasuddendecreaseinloadcarryingcapacityasthesurfacebondisbroken.Theextenttowhichtheloadreducesisdependentontheeffectivenessofthemechanicalembossments.Ductilebehaviorinwhichcasethemechanicalshearconnectioniscapableoftransferringtheshearforceuntilfailureoccurs.Thismaybeflexuralorbylongitudinalshear.ShearbondfailureBrittlebeha25BehaviorofCompositeSlabsBehaviorofCompositeSlabs26 Longitudinalshearincompositeslabs Threetypesofshearconnectionbetweenaprofiledsteelsheetandaconcreteslab:(1)naturalbondbetweenthetwo,knownasfrictionalinterlock(2)mechanicalinterlockprovidedbypressingdimplesorribsintothesheet(3)endanchorageprovidedbymeansofshot-firedpins,orbyweldingstudsthroughthesheetingtothesteelflange.DeterminationofthelongitudinalshearstrengthThe m-k or shear-bond testLongitudinalshearincompos27Mode1brittle(ornon-ductile)behaviorMode2ductilebehaviorMode1brittle(ornon-ductile28EmpiricalmethodforevaluatinglongitudinalshearresistanceEmpiricalmethodforevaluat29Themeritsofusingprofiledsteeldeckcompositefloors:itsefficienciesinconstructionanditshigherloadcarryingcapacityoverthetraditionalsteeldeckasshuttering.Theshear-bondresistanceisessentialtotheinteractionbetweensteelsheetingandconcreteatthesheet-concreteinterface,andgovernsthecompositeslabdesign.Shear-bondtestsmustbecarriedouttocalibratedifferenttypesofsteeldecks.Normally,slabsaretestedwithnoshearconnectors.Themeritsofusingprofileds30RelationshipbetweenfailuremodeandspanIflongitudinalshearresistanceoftheslabisnotsufficient,itcanbeincreasedbytheuseofsomeformofendanchorage.Relationshipbetweenfailurem31PartialconnectionmethodThepartialconnectionmethodcanalsobeusedfortheverificationoftheresistancetolongitudinalshear.(slabswithductilebehavior).PartialconnectionmethodThep32压型钢板组合楼板课件33TheverificationprocedureisillustratedintheFigureabovefor two slabs with different types of loading and span.Resistant moment diagrams and design bending momentdiagramsareplottedagainstLxonthesameaxissystem.Foranycross-sectionofthespan,thedesignbendingmomentMSdcannotbehigherthanthedesignresistanceMRd.Theverificationprocedureis34Partialconnectionmethod(anotherexpression)Thepartialconnectionmethodcanalsobeusedfortheverificationoftheresistancetolongitudinalshear.Partialconnectionmethod(ano35Thepartial-interactiondesignmethodrequiresthatthemeanultimateshearstressisdetermined.Thepartial-interactiondesign36压型钢板组合楼板课件37Vl designlongitudinalshearforceofthecompositeslab Vushearbondresistancedeterminedbytests组合楼板前提：压型钢板与混凝土组合作用，要确保组合楼板前提：压型钢板与混凝土组合作用，要确保界面黏结强度：界面黏结强度：Shear-bondstrengthrequirement纵向抗剪强度验算纵向抗剪强度验算Vldesignlongitudinalsh38AnalysisofCompositeSlabs（组合楼板（组合楼板受力分析）受力分析）linearelastic;linearelasticwithmomentredistribution（线弹性分析、考虑弯矩重分布的线弹性分析）.plasticaccordingtothetheoryofplastichinges（极限状态的塑性分析）.Higherorderanalysistakingintoaccountnon-linearbehaviourandslip（考虑非线性特性以及滑移的高阶分析）.AnalysisofCompositeSla39VerificationofProfiledsteelsheetingasshutteringatultimatelimitstate(ULS)Thesheetingshouldresisttoconstructionandwetconcreteloads.Bendingmomentresistanceofthesectionisthengivenby:Verificationofprofiledsteelsheetingasshutteringatserviceabilitylimitstate(SLS)VerificationofProfiledsteel40Fortheultimatelimitstates(强度极限状态；uncrackedsection)Fortheserviceabilitylimitstates（使用极限状态）Theslabiscomparabletoacontinuousbeamofconstantinertia,equalinvaluetotheaverageinertiaofthecrackedanduncrackedsection（均匀截面模量）.Long-termloadingeffectsontheconcretearetakenintoaccountusingavariationinthemodularratioEa/Ec（考虑长期、短期效应时引入混凝土模量系数来简化）.Forsimplification.Fortheultimatelimitstates413.4RESISTANCESOFSECTIONSSectionI:ultimatemomentofresistancefailureforpositivebending.SectionII:ultimatemomentofresistancefailurefornegativebending.SectionIII-IV:ultimateresistancetoverticalshearfailure.SectionV:ultimateresistancetolongitudinalshearfailure.3.4RESISTANCESOFSECTIONSSe42Verificationofcompositeslabatultimatelimitstate(ULS)Saggingbendingresistance.Thatfailuremodeisreachedifthesteelsheetingyieldsintensionorifconcreteattainsitsresistanceincompression.Verificationofcompositeslab43compositeslabatultimatelimitstateCase1PlasticneutralaxisabovethesheetingCase2Plasticneutralaxisinsteelsheetingcompositeslabatultimatelim44Case1PlasticneutralaxisabovethesheetingCase1Plasticneutralaxis45Case2PlasticneutralaxisinsteelsheetingCase2Plasticneutralaxis46压型钢板组合楼板课件47VerificationofthehoggingbendingresistanceVerificationofthehoggingbe48BendingresistanceanddeflectionAtconstructionstage:bendingresistanceofthesteeldeckischeckedasthefollowing:Deflectionofthesteeldeckmustsatisfythedeflectionrequirementas:Bendingresistanceanddeflect49AtcompositeslabstageBendingresistance,diagonalshearresistanceandshearbondresistanceshouldbecheckedIfsufficientshearbondisprovidedattheinterfacebetweenconcreteandsteelsheeting,itsbendingresistancenormaltostrongbendingdirectionasthefollowing:Positivebending:AtcompositeslabstageBendin50Whenacompositeslabspanscontinuouslyoversupportingbeams,withnegativereinforcementovertheinternalsupportregion,thenegativemomentresistanceoftheslabcanbecalculated.Negativebending:Thebendingresistancenormaltoweakbendingdirectionistreatedasreinforcedconcreteslab.Whenacompositeslabspansco51Vertical shear verificationVerticalshearverification52Verticalandpunchshearresistance（抗冲切承（抗冲切承载力）力）punchshearresistanceischeckedasVerticalandpunchshearresis53Longitudinalshearresistance(纵向抗剪承向抗剪承载力）力）Toenableacompositeslab,thelongitudinalshearbondresistanceattheinterfacebetweentheconcreteandtheprofileddeckshouldbesufficient.Diagonalshearresistance（斜截面抗剪）（斜截面抗剪）Longitudinalshearresistance54Deflections组合板挠度，按荷载短期效应组合与荷载长期效应组合计算。Fordeflectionundershorttermload（荷载短期效应）,theareaofconcretesectionisdividedbya E(a E=E s/E c);fordeflectionunderlongtermload（荷载长期效应）,dividedby2a E.Deflections55压型钢板组合楼板课件563.5Somedetailingrequirements（构造要求）（构造要求）DetailingistoensurethatthefullstrengthofcomponentscanbedevelopedunderthemostadverseconditionsTheeffectsofcorrosiononsteelsheetsabout1mmthickaremoreseverethanonthickersections,sothematerialsareusuallygalvanized.Theoveralldepthofacompositeslabshouldnotbelessthan90mm,whilethedistancebetweenthetopsurfaceofconcreteandthetopofthesteelribsshouldnotbelessthan50mm.TheconcretegradeisbetteroverC20.3.5Somedetailingrequirement57Therequiredbearingoverlapsofcompositeslabsoverthedifferent（构造要求）（构造要求）Therequiredbearingoverlaps58When shear studs are welded through steelprofilestothetopflangeofasteelbeam,thediameterofthestudsshouldbe13to16mmifl3m,and16to19mmif3mlMM=(g+q)l02/8=(3.56+63DiagonalshearstrengthTake one wave length(200 mm)as a checking unit,subjectedtoshearforceas:V1=V200/1000=7.0200/1000=1.4kNf t=1.10N/mm2(C20)0.7ftbbmh0=0.71.10(70+50)/2115=5.31kNV1CalculationofdeflectionTakeonewavelength(200mm)asacheckingunit.Elasticmodulusofconcrete:Ec=2.55104N/mm2aE=Es/Ec=2.06105/2.55104=8.08DeflectionundershorttermloadingEquivalentwidthofconcreteslab:DiagonalshearstrengthTak64Equivalentwidthofrib:secondmomentofareaofthetransformedsectionofonewavelengthofcompositeslabEquivalentwidthofrib:65secondmomentofareapermeterofslab:Isk=5Isk=5475104=0.238108mm4pk=gk+qk=2.954+2=4.964kN/mDeflectionunderlongtermloadingsecondmomentofareapermete66SteelDeckP3623SteelDeckP362367压型钢板组合楼板课件68压型钢板组合楼板课件69压型钢板组合楼板课件703.7AdvancedcompositefloorsystemsanumberoftrendsinmodernconstructionhaveledtothedevelopmentofmoreadvancedformsofcompositeconstructionFabricatedbeamswithtappedwebs3.7Advancedcompositefloors71HaunchedbeamsHaunchedbeams72CompositetrussesCompositetrusses73StubgirdersStubgirders74ParallelbeamgrillagesystemParallelbeamgrillagesystem75BeamwithsinglewebopeningsBeamwithsinglewebopenings76BeamswithwebopeningsCellularandcastellatedbeamsBeamswithwebopenings77SlimfloorsystemSlimfloorsystem783.8CONCLUDINGSUMMARYThedesignofacompositeslabmustconsidertheperformanceoftheprofiledsteelsheeting,whenitactsasshutteringforthewetconcreteduringexecution,aswellasthecompositeperformanceofthesteelandhardenedconcreteundertheimposedfloorloading.Attheexecutionstage,theprofiledsteelsheetingactsasathin-walledmember.Itsdesignmusttakeintoaccountthepossibilityoflocalbuckling.Thedesignofthecompositeslabmustconsidertheresistancetopositiveandnegativemomentsandalsotoverticalandlongitudinalshear.3.8 CONCLUDINGSUMMARY79Theresistancetolongitudinalshearatthesteel/concreteinterfaceislargelyderivedfromembossmentsinthesteelsheetorfromconnectorsplacedattheendsofthespans.Empiricalmethodsareusedtoensureadequateshearresistance.shallowfloorsystems,whichcombinethefloorandslabinthesameverticalspace,offeracompetitivealternativetoconcreteflatslabconstruction.Inseekinganeconomicdesign,considerationshouldbegiventooverallprojectcostsandflexibilityforfuturechangesinbuildinguseandservices.Theresistancetolongitudinal80Reviewpoints:Whatisthelongitudinalshear?Whicharegoverningfactorsindesignofacompositeslab?Determinationofthelongitudinalshearbyshearbondtestsanddefectsofthem-kmethod.简述压型钢板-混凝土组合板在施工阶段和使用阶段有哪些破坏模式。FurtherreadingofdesignmethodsforresistancetofireReviewpoints:81Fireresistance（抗火性能）The composite floor must provide satisfactoryperformance in terms of stability,integrity andinsulationintheeventoffire.Thethicknessoftheslabisdirectlyrelatedtoitsinsulationcapacity.Integrityisensuredbythesheetingwhichactsasashieldtoconcreteandhelpstocontainspalling.Stabilityofthestructuredependsuponconventionalreinforcementprovidedfortheslab.Asmallamountof additional reinforcement may be neededdependingupontheextentoffireresistanceneeded.Fireresistance（抗火性能）Thecomp82Basedonalargenumberoffiretests,manycarriedoutinassociationwithBritishSCI,adesignguidehas been published,which provides practicalassistanceinassessingfireresistanceofcompositeslabs.抗火评定：fire-proofrating:1hr,2hr,etc.Basedonalargenumberoffir83谢谢！谢谢！84
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