钢管混凝土哑铃形轴压长柱极限承载力研究

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1、第25卷第4期Vol.25No.4工程力学2008年4月Apr.2008ENGINEERINGMECHANICS121文章编号：1000-4750(2008)04-0121-07钢管混凝土哑铃形轴压长柱极限承载力研究*12陈宝春，盛叶(1．福州大学土木工程学院，福建，福州350002；2．福建农林大学交通学院，福建，福州350002)摘要：共进行了10根不同长细比的钢管混凝土哑铃形轴压长柱(5根强轴向破坏，5根弱轴向破坏)的试验研究。对于沿强轴方向失稳破坏的试件，通过在弱轴方向焊接波形钢板以加大其抗弯刚度来实现，试验结果表明这一方法是可行的。与单圆管轴压长柱相似

2、，哑铃形轴压长柱试件的极限承载力和弹塑性阶段切向刚度均随着试件长细比的增加而减小。但相同长细比情况下，与单圆管长柱弹性失稳破坏不同，哑铃形长柱属弹塑性失稳破坏。提出了哑铃形轴压长柱的非线性有限元计算方法，并进行了长细比对极限承载力影响的参数分析。研究结果表明：哑铃形轴压长柱的稳定系数与单圆管的不同，但沿强轴、弱轴向失稳的极限承载力随长细比变化而变化的规律基本一致，提出了将二者统一的稳定系数简化计算公式。关键词：钢管混凝土；哑铃形；轴压；长柱；极限承载力；有限元中图分类号：TU398文献标识码：ARESEARCHONLOAD-CARRYINGCAPACITYOFC

3、ONCRETE-FILLED-STEELTUBULARDUMBBELL-SHAPEDLONGCOLUMNSUNDERAXIALLOADS*12CHENBao-chun,SHENGYe(1.CollegeofCivilEngineering,FuzhouUniversity,Fuzhou,Fujian350002,China;2.CollegeofTransportation,FujianAgricultureandForestryUniversity,Fuzhou,Fujian350002,China)Abstract:Experimentsof10concre

4、te-filled-steeltubular(CFST)dumbbell-shapedLongcolumnswithvariousslendernessratiosubjectedtoaxialloadwerecarriedout,inwhich5specimenwerefailedinthestrong-stress-axisdirection;another5werefailedintheweak-stress-axisdirection.Itisprovedbythetestthatthefailureofdumbbellshapedspecimenins

5、trong-stress-axisdirectioncanberealizedbyweldingcorrugatedsteelwebsinitsweak-stress-axisdirectiontoincreaseflexiblerigidityinthisdirection.Similarwiththelongcolumnsofsingletubesection,theload-carryingcapacityandtheelastic-plastictangentialstiffnessofCFSTdumbbell-shapedlongcolumnsdecr

6、easewiththeincreasingofslendernessratio.Butelastic-plasticinstabilityoccurredondumbbell-shapedlongcolumnsinsteadoftheelasticinstabilityinoneofsingletubesectionwithsameslendernessratio.Anonlinearfiniteelementmethodisprovidedfordumbbell-shapedlongcolumn,andtheinfluenceofslendernessrati

7、oonitsload-carryingcapacityisanalyzedbyparametricstudies.Itisshownthatthestabilitycoefficientofdumbbell-shapedlongCFSTcolumnsisdifferentfromthatoflongCFSTcolumnsofsingletubesection.However,therulesofload-carryingcapacityintheweak-stress-axisandstrong-stress-axisdirectionsfordumbbell-

8、shapedlongCF