钢结构基础,课件.ppt

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1、1.4LimitStatesandtheLawofProbabilityLimitStatesofSteelStructure钢结构的极限状态和概率极限状态法1.4.1LimitStatesofSteelStructure钢结构的极限状态1.4.2LoadEffectAnalysisoftheStructure结构的荷载效应分析1.4.3TheLawofProbabilityLimitStates概率极限状态法1.4.4DesignExpression设计表达式1.4.1LimitStatesofSteelStructure钢结

2、构的极限状态LimitStatesofSteelStructureisdividedintotwotypes:thelimitStateofload-bearingcapacityandthelimitStateoftheregularusage.钢结构的极限状态分为承载力极限状态和正常使用极限状态两大类。1.LimitStateofload-bearingcapacitycorrespondstothesituationthatthestructureorthememberreachthemaximumbearingcapac

3、ity,orthedeformationdisallowthemtocarrymoreforce,including:overturn,strengthdamage、fatigueddamage、failureofstability、thestructureturnsintothechangeablesystemortheexcessiveplasticdeformationoccurs.承载力极限状态对应于结构或构件达到最大承载力或出现不适于继续承载的变形，包括倾覆、强度破坏、疲劳破坏、丧失稳定、结构变为机体或出现过度的塑性变

4、形。2.LimitStateoftheregularusagecorrespondstothesituationthatthestructureorthememberreachthecertainallowablevaluefortheregularusageorendurance,including:thedeformationforregularusage(orappearance),vibrationandthepartdamage.正常使用极限状态对应于结构或构件达到正常使用或耐久性能的某项规定限值，包括出现影响正常使用

5、（或外观）的变形、振动和局部破坏。1.4.2Loadeffectanalysisofthestructure结构的荷载效应分析Designingthesteelstructureneedtohandletwofactors：Oneistheresistanceofthestructureandmember；thesecondistheloadeffectexertedonthestructure.Loadeffectcanbegotbymeansoftheinnerforceanalysis.设计钢结构需要处理两个方面的因素：一

6、是结构和构件的抗力；二是荷载施加于结构的效应(荷载效应通过内力分析来解)。Consideringoftheeffectofdeformationornot,theinnerforceanalysisisdividedinto:onerankanalysisandtworankanalysis;内力分析根据是否考虑变形影响分为：一阶分析和二阶分析；Consideringoftheplasticperformanceofsteelmaterialornot,theinnerforceanalysisisdividedinto:ela

7、sticanalysisandinelasticanalysis.内力分析根据是否考虑钢材塑性性能分为：弹性分析和非弹性分析。1.4.3TheLawofProbabilityLimitStates概率极限状态法Thefundamentalproblemforstructuredesigntosolveistochooseanoptimumequilibriumbetweenthereliabilityandeconomy，andmakethestructureconstructedperthemosteconomicmethod

8、meetthedesiredperformancedemandsperproperdegreeofreliability.LimitStatesdesignmethod,whichisbasedonprobabilitytheory,hasbeenusedins