Improved Algorithm for Efficient and Realistic Creep.pdf

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1、ACISTRUCTURALJOURNALTECHNICALPAPERTitleno.109-S58ImprovedAlgorithmforEfficientandRealisticCreepAnalysisofLargeCreep-SensitiveConcreteStructuresbyQiangYu,ZdeneˇkP.Bažant,andRomanWendnerRecentcompilationofdataonnumerouslarge-spanprestressedcreepeffectswerealsodocumentedforfourlargesegmen-segment

2、allyerectedboxgirderbridgesrevealedgrossunderesti-tallyerectedboxgirdersinJapan.3,6,7Asubsequentsearchofmationoftheirmulti-decadedeflections.Themaincausehasbeendataonsegmentallyerectedprestressedboxgirderbridges,identifiedasincorrectandobsoletecreeppredictionmodelsinundertakenundertheauspiceso

3、ftherecentlyestablishedvariousexistingstandardrecommendationsandisbeingaddressedRILEMCommitteeTC-MDC(Multi-DecadeCreep),ledtoinaseparatestudy.However,previousanalysesoftheexcessivealistof69largespans(in10countries)thatsufferedgrosslydeflectionsoftheKoror-Babeldaob(KB)BridgeinPalauandof8-10exce

4、ssivelong-timedeflections.ItislikelythatmanyfourJapanesebridgeshaveshownthatamoreaccuratemethodmorecasesofexcessivedeflectionsexistworldwide.Clearly,ofmulti-decadecreepanalysisisrequired.Theobjectiveofthispaperistoprovideasystematicandcomprehensivepresentation,theproblemiswidespreadanditscause

5、mustbesystematic.appropriatenotonlyforbridgesbutalsoforanylargecreep-AnalysesofthedataontheKBBridgeandtheJapanesebridges3,6,7withModelB3(calibratedbymulti-decadelabo-sensitivestructure.Foreachtimestep,thesolutionisreducedtoanelasticstructuralanalysiswithgenerallyorthotropicelasticratorytests11

6、-13)showedthatthemaincausesofthegrossmoduliandeigenstrains.Thisanalysisshouldnormallybethree-underestimationaretwofold:dimensional(3-D).Itcanbeaccomplishedwithacommercialfinite1.IncorrectandobsoletematerialmodelsforconcreteelementcodesuchasABAQUS.BasedontheKelvinchainmodel,creepsurvivinginstan

7、darddesignrecommendationsofACI,theintegral-typecreeplawisconvertedtoarate-typeformwithCEB-fib,andotherengineeringsocieties;andinternalvariables,whichaccountfortheprevioushistory.Fortime2.Anoversimplifiedmethodofcreepstructuralanalysis.s