匝道桥地震响应影响要素分析

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1、桥梁建设2015年第45卷第4期(总第233期)58BridgeConstruction，Vo1．45，No．4，2015(TotallyNo．233)文章编号：1003—4722(2015)O4—0058—06匝道桥地震响应影响要素分析张菊辉，管仲国(1．上海理工大学环境与建筑学院，上海200093；2．同济大学土木工程防灾国家重点实验室，上海200092)摘要：为探求匝道桥几何非规则性对结构地震响应的影响规律，基于嘉闵线匝道桥，采用SAP2000软件建立结构有限元分析模型，分析不同跨径组合、纵坡、曲率半径和地震动输入方向下的匝道桥地震响应。结果表明

2、：与简支梁桥相比，多跨连续梁桥顺桥向固定墩、横桥向矮墩和过渡墩的响应均变大；纵坡大小对桥梁纵向地震响应影响轻微，但在横桥向设置大纵坡可减小高墩区墩柱的地震响应；小曲率半径下采用切向或法向输入与地震动最不利输l入方向存在角度偏差，会低估结构地震响应，大曲率半径下其地震响应与直线桥基本一致，可简化为直线桥进行分析。关键词：匝道桥；桥墩；跨径组合；纵坡；曲率半径；地震动输入方向；有限元法；地震响应分析中图分类号：U448．17；U442．55文献标志码：AAnalysisofFactorsInfluencingSeismicResponsesofRampBr

3、idgesZHANGJu—hui．GUANZhong—guo(1．sch0olofEnvironmentandArchitecture，UniversityofShanghaiforScience＆Technology，Shanghai200093，China；2．StateKeyLaboratoryforDisasterReductioninCivilEngineering，TongjiUniversity，Shanghai200092，China)Abstract：Toprobeintothelawsofinfluencesofthegeometr

4、yirregularitiesoframpbridgesontheseismicresponsesofthehridgestructures，afiniteelementanalysismodelforthestructureswasestablished，usingthesoftwareSAP2000basedontheexampleofarampbridgeontheJiaminElevatedRoadLineandtheseismicresponsesoftherampbridgesunderthedifferentspanarrange—men

5、t。longitudinalslopes，curvatureradiiandgroundmotioninputdirectionswereanalyzed．Theresultsoftheanalysisshowthatascomparedwithasimply—supportedbeambridge，themulti—spanc0ntinuousbeambridgecanhavesignificantincreaseoftheseismicresponsesinthefixedpiersintheIongitudinaldirectionandinth

6、elowpiersandtransitionpiersinthetransversedirection．Theinfluencesofthelongitudinalslopechangesonthelongitudinalseismicresponsesoftherampbridgesareslight，however，thearrangementoftheheavyslopesinthetransversedirectionishelpfu1tothealleviationoftheseismicresponsesofthecolumnsintheh

7、ighpierarea．UnderthesharDcurvatureradiioftherampbridges，theangledeviationsexistbetweenthegroundmotionin—Dutinthetangentialandnormaldirectionsandtheworstgroundmotioninputdirection，whichmavleadtotheunderestimationoftheseismicresponsesofthestructures．Underthegentlecurva—tureradii，t

8、heseismicresponsesofthecurvedrampbridgesarebasi