哈工大荷载与结构设计方法课件.ppt

《哈工大荷载与结构设计方法课件.ppt》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、Chapter5StatisticalAnalysisofLoadsChapter5:StatisticalAnalysisofLoads5.2ProbabilityModelsofLoads5.4RepresentativeValuesofLoads5.1LoadsandActionsContents5.5CombinationofLoadEffects5.3StatisticalAnalysisofLoads5.1LoadsandActionsChapter5StatisticalAnalysisofLoads5

2、.1LoadsandActions…1Anactionis:Anassemblyofconcentratedordistributedmechanicalforcesactingonastructure(directactions),orThecauseofdeformationsimposedonthestructureorconstrainedinit(indirectactions)5.1.1DefinitionsofLoadsandActionsActionDirectAction—LoadIndirectA

3、ction5.1.2TypesofActions1.ClassificationaccordingtothevariationoftheirmagnitudewithtimePermanentaction,whichislikelytoactcontinuouslythroughoutagivenreferenceperiodandforwhichvariationsinmagnitudewithtimearesmallcomparedwiththemeanvalue.5.1LoadsandActions…22.Cl

4、assificationaccordingtotheirvariationwithspaceFixedaction,whichhasafixeddistributiononastructure;Freeaction,whichmayhaveanarbitraryspatialdistributionoverthestructurewithingivenlimits.3.ClassificationaccordingtothestructuralresponseStaticaction,i.e.notcausingsi

5、gnificantaccelerationofthestructuralorstructuralelements;Dynamicaction,i.e.causingsignificantaccelerationofthestructuralorstructuralelements.Variableaction,forwhichthevariationinmagnitudewithtimeisneithernegligibleinrelationtothemeanvaluenormonotonic.Accidental

6、action,whichisunlikelytooccurwithasignificantvalueonagivenstructureoveragivenreferenceperiod.5.2ProbabilisticModelsofLoadsChapter5StatisticalAnalysisofLoads5.2ProbabilityModelsofLoads…1(1)Thedesignreferenceperiodisdividedintorequalintervals5.2.1StochasticProces

7、sModelofLoadsAssumptionsofStationaryBinomialRandomProcessActually,loadsarerandomvariablesvaryingwithtimeinthedesignreferenceperiodi.e.loadsarerandomprocess.Ingeneral,loadsaretreatedasstationarybinomialrandomprocess.(2)Ineachinterval,theprobabilityoftheloadQoccu

8、rringisp,whiletheprobabilityofnotoccurringis.(3)Ineachinterval,whentheloadQoccurs,itsmagnitudeisanon-negativerandomvariable,anditsprobabilitydistributionsduringdifferentinte