大跨度混合梁斜拉桥弹塑性极限承载力分析.pdf

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1、桥梁建设2012年第42卷第5期(总第215期)44BridgeConstruction，Vo1．42，No．5，2012(TotallyNo．215)文章编号：1003—4722(2012)05—0044—07大跨度混合梁斜拉桥弹塑性极限承载力分析徐金勇，颜全胜。(1．惠州市道路桥梁勘察设计院，广东惠州516002；2．华南理工大学土木与交通学院，广东广州510641)摘要：为研究混合梁斜拉桥的弹塑性极限承载力，基于连续体三维虚功增量方程，建立空间薄壁梁单元的U．L．列式增量平衡方程，采用分段分块变刚度法计算

2、单元的弹塑性刚度矩阵，并编制相应的斜拉桥弹塑性极限承载力空间分析程序ULCA。采用ULCA对某主跨480m的双塔三跨空间双索面混合梁斜拉桥成桥进行弹塑性极限承载力分析，分析结果表明：该桥的荷载安全系数志一3．1465，因混凝土主梁受压区破坏而达到极限状态；材料非线性对边跨位移、索力及桥塔位移的影响远大于对中跨的影响；极限荷栽作用下，材料非线性对主梁和桥塔的轴力基本无影响，但弯矩重分布比较明显。关键词：斜拉桥；混合梁；弹塑性分析；极限承载力；有限元法中图分类号：U448．27文献标志码：AAnalysisofEl

3、asto。-PlasticUltimateLoadBearingCapacityofLongSpanHybridGirderCable-StayedBridgeXUJin-yong，YANQuan—sheng(1．HuizhouCityRoadandBridgeSurveyandDesignInstitute，Huizhou516002，China；2．SchoolofCivilEngineeringandTransportation，SouthChinaUniversityofTechnology，Guang

4、zhou510641，China)Abstract：Tostudytheelasto—plasticultimateloadbearingcapacityoflongspanhybridgirdercable—stayedbridge，theincrementalequilibriumequationofU．L．formulationforaspacialthin-walledbeamelementwasdevelopedonthebasisoftheincrementalvirtualworkequation

5、of3-di—mensionalcontinuum．Theelasto—plasticstiffnessmatrixofthebeamelementwascalculatedbythesegmentandblockvariablestiffnessmethodandthecorrespondingspacialanalysisprogramULCAfortheelasto‘—plasticultimateloadbearingcapacityofthecable——stayedbridgewascorn—pli

6、ed．TheULCAwasthenusedtoanalyzetheelasto—plasticultimateloadbearingcapacityofacompletedthree—spanhybridgirdercable—stayedbridgewithdoublepylons，doublespacialcableplanesandwithamainspan480m．TheresultsoftheanalysisdemonstratethattheloadsafetyfactorofthebridgeiS

7、k一3．1465andthebridgereachestheultimatestateonaccountoffailureofthecompressionareasofmaingirderofthebridge．Theinfluencesofmaterialnonlinearityonthedisplacementandcableforcesofthesidespanandonthedisplacementofpylonsarefargreaterthanthoseonthecentra1span．Undert

8、heactionoftheultimate1oad。themateriaInonlinearitybasicallyhasnoinfluenceontheaxialforcesofthemaingirderandpylons，howevertheredistri—butionofbendingmomentinsuchcaseiSquitenotable．Keywords：cable—s