高温作用后钢筋混凝土短柱轴压力学性能试验研究

JournalofBuildingStructures32420114Vol.32No.4Apr.20110161000-6869201104-0117-081314121．4100822．CA900893．1500904．510640、。、、、。、。。TU375.3TU317.1AExperimentalstudyonaxialmechanicalbehaviorofreinforcedconcretestubcolumnswithpre-loadafterexposuretohightemperaturesZHANGJiaguang13HUOJingsi14XIAOYan121．KeyLaboratoryofBuildingSafetyandEnergyEfficiencyofChinaMinistryofEducationHunanUniversityChangsha410082China2．UniversityofSouthernCaliforniaLosAngelesCA90089USA3．CollegeofCivilEngineeringHarbinInstituteofTechnologyHarbin150090China4．StateKeyLaboratoryofSubtropicalBuildingScienceSouthChinaUniversityofTechnologyGuangzhou510640ChinaAbstractThereinforcedconcreteRCstubcolumnswithsustainedpre-loadwereheatedandcooledusingaspecially-builtelectricalfurnace．Thetemperaturefieldsofthecross-sectionsandaxialdeformationsofthecolumnsweremeasured．Aftertheentireperiodofhightemperatureteststheaxiallymechanicalbehaviorofthefire-damagedRCstubcolumnswereexperimentallystudied．TheeffectsofhightemperatureaxialloadlevelandcoolingphaseonthecompressivecarryingcapacityaxialstiffnessandductilityofRCstubcolumnswerediscussed．Thetestresultsshowthatspecimenswithsustainedpre-loadafterexposuretohightemperatureremarkablesufferresidualdeformationswhichareaccumulatedduringthecoolingphase．ThesustainedaxialloadhassignificanteffectsonthecompressivecarryingcapacityaxialstiffnessandductilityofRCstubcolumns．Thecarryingcapacityandaxialstiffnessarefoundtobeimprovedandthepost-fireductilityisfoundtobedeteriorated．Howeverthesustainedaxialloadhasmoresignificanteffectsonaxialstiffnessandductilitythancarryingcapacity．Itisrecommendedthattheeffectofpre-loadshouldbetakenintoconsiderationinassessingthebehavioroffire-damagedRCstructures．KeywordsreinforcedconcreteRCstubcolumnentireperiodofhightemperatureexposuresustainedpre-loadaxialcompressionhightemperaturetestmechanicalbehaviorIRT0619507780692009KB23。1984—。[e-mail]2009107110。1。1993212、、。19963。199741220℃～950℃。。20075111ISO-834。199964、、。。。Lie1984720.330.35。。JauHuang2008860.1。2h4h67%57%。。0.4～0.6。11.128。1LBtonn=No/NuNoNu。NTuEAEAT。。19。410mmHRB3351.4%6mmHPB23590mm20mm。C35425#5～20mm。10-11HRB335HPB235543MPa397MPa618MPa558MPa1.9×105MPa2.0×105MPa。210-11。1.2KYL-10-12Y12。2a200t。280mm330mm。8111Table1SummaryofstubcolumntestinformationB×B×L/mmT/℃nNo/kNNTu/kNNTu/NuEAT/kNEAT/EAS120——60318868221SF140400004720.7824048030.456SF1444000.42427261.2048207100.925SF146150×150×3004000.63636681.1085780260.652SF160600005410.8973420210.386SF1646000.42427281.2076934650.782SF1666000.63637001.1616269430.707S220——61219643361SF280150×150×300800005700.9312643170.274SF2848000.42447461.2193567180.370“S”“F”“1”“2”“4”400℃“4”0.4。2Table2Mixproportionsandstrengthofconcrete/kg·m－342.528fcu28/MPafcu/MPa144217560512280.40.3334.436.0244217560512280.40.3337.038.31Fig．1Maindimensionsofspecimensandstraingaugeslocationab2Fig．2Arrangementofstubcolumnanddeformationtest①-、②-。2b11。1.3、。。400℃600℃10℃/min800℃10℃/min700℃6℃/min800℃。400℃1h600℃800℃10℃/min。1。3400℃、600℃、800℃--。SF144。。3h911。1h0.01mm。3-Fig．3Testingtemperatureandtimecurves1.4。400℃600℃800℃。。。。4。4Fig．4Failuremodesofsomespecimensaftertest5-SF164。SF144、SF146、SF166SF2841.00、0.59、0.760.99。5-Fig．5Hightemperaturetestingaxialdeformationandtimecurves22.1-67N-ε。6N-ε。-、。6-。-。、、。7N-ε021a400℃b600℃c800℃6N-εFig．6Loadandaxialdeformationcurvesan=0bn=0.4cn=0.67N-εFig．7Loadandaxialdeformationcurves。800℃NuS1/NuS2NuS1、NuS2S1、S2。7--。2.21NTu、EAT、NTu/NuEAT/EA。-0.4NTuNo0.4NTu-No。8。8a。199313199514。8a13-14。。8b。ab8NTu/NuFig．8EffectofhightemperatureandaxialcompressionratiooncarryingcapacityNTu/Nu9EAT/EA9a。9a121。9b。ab9EAT/EAFig．9EffectofhightemperatureandaxialcompressionratioonaxialstiffnessEAT/EA6～9。、、。2.315。。εy=NTu/EATεu-6。3、。10μT/μoμoμT3Table3Ductilitycoefficientsofstubcolumnsεy×10－6εu×10－6μS168031264.60SF140116640093.44SF14488518812.13SF146115623162.00SF160158260043.80SF164105013691.30SF166111714251.28S263531004.88SF280215760732.82SF284209128381.36ab10Fig10Effectsofhightemperatureandaxialcompressionratioonductilitycoefficient。3。16221。。11PhanCarino200417200218。400℃600℃。aPhan200417b20021811Fig．11Strengthmodelsofconcreteathightemperature。20021811b。--LieCelikkol199119。1。2Ns+Nc=Nεs=εc。NsNcεsεc。12。400℃400℃。18。12Fig．12Effectofpre-loadonpost-firecarryingcapacity41。2-。3、。4。。3211．J．2007161127-135．ZHANGZhimeiYEZhimingLIUTao．ResearchprogressinfireresistanceofreinforcedconcretestructuresJ．JournalofNaturalDisasters2007161127-135．inChinese2．J．199326347-54．LUZhoudaoZHUBolongZHOUYuehua．ExperimentalstudyonbehaviorofreinforcedconcretesimplebeamsubjecttofireJ．ChinaCivilEngineeringJournal199326347-54．inChinese3．J．1996527-11．DONGYuliFANWeichengWANGQinganYANGBangrong．Studyonresidualload-bearingcapacityandreliabilityindexofreinforcedconcreteslabpost-fireJ．FireSafetyScience1996527-11．inChinese4．J．199718413-22．SHIXudongLIHuadongGUOZhenhai．ExperimentalinvestigationonbehaviorofreinforcedconcreteaxialcompressioncolumnatelevatedtemperatureJ．JournalofBuildingStructures199718413-22．inChinese5．J．200728524-31．WUBoXUYuye．Experimentalstudyonreinforcedconcretecolumn