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1、第31卷第8期2010年8月建筑结构学报JournalofBuildingStructuresVol131No18Aug12010007文章编号:1000-6869(2010)08-0045-09纯压圆弧形钢管桁架拱平面内稳定性能及设计方法郭彦林,郭宇飞,窦超(清华大学土木工程系,北京100084)摘要:目前针对钢管桁架拱平面内稳定性能及承载力的研究较少,缺少相应的设计方法。提出了钢管桁架拱截面剪切刚度表达式,考虑剪切变形的影响推导了纯压两铰圆弧桁架拱屈曲荷载的简化计算公式以及换算长细比表达式。基于有限元方法,全面分析
2、了截面高宽比、矢跨比、腹杆夹角及腹杆截面尺寸等不同参数对平面桁架拱和空间桁架拱弹性屈曲性能的影响,结果表明采用简化公式与有限元分析结果吻合良好。借鉴实腹拱和格构柱的稳定设计方法,采用大挠度弹塑性有限元法系统研究了平面及空间纯压桁架拱的相关稳定承载力,发现节间弦杆长细比与桁架拱整体长细比的比值是衡量局部稳定对整体稳定影响的关键参数,在此基础上提炼出纯压桁架拱的相关作用影响系数,并拟合得到了纯压桁架拱的稳定设计曲线,从而为一般荷载作用下压弯桁架拱的稳定承载力的设计奠定了基础。关键词:钢管桁架拱;弹性屈曲;剪切变形;换算长细
3、比;相关稳定;设计曲线中图分类号:TU3931302文献标志码:AIn-planebucklinganddesignoftwo-hingedsteeltubecirculartruss-archesunderpurecompressionGUOYanlin,GUOYufe,iDOUChao(DepartmentofCivilEngineering,TsinghuaUniversity,Beijing100084,China)Abstract:Untilrecently,thecorrespondingstability
4、designmethodisabsentforthelackofresearchesonthein-planestabilityandload-carryingcapacityofsteeltubetruss-arches.Inthispaper,firstlytheexpressionofsectionalshearstiffnessisproposed,andthebucklingloadsandmodifiedslendernessratiooftwo-hingedcirculararchesunderpurec
5、ompressionarederived,consideringtheeffectsofsectionalsheardeformationonbucklingbehavior.Secondly,byadoptingfiniteelementnumericalmethod,thebucklinganalysisofapurecompressivearchiscarriedouttoinvestigatetheinfluenceofdifferentparametersontheelasticbucklingbehavio
6、rofplanarandspatialtruss-arches,suchassectionalheight-to-widthratio,rise-to-spanratio,web-memberincludedangleandsectionaldmiension.Itindicatesthatthebucklingloadscalculatedbytheformuladerivedaboveareingoodagreementwithnumericalresults.Finally,referringtothestabi
7、litydesignmethodofsolidwebsarchandlatticedcolumnsincurrentChinesecodeforsteelstructures,byelasto-plasticfiniteelementmethodtheinteractiveultmiateload-carryingcapacityofpurecompressivetruss-archisstudied,consideringtheinfluenceofmemberlocalbucklingonglobalstabili
8、ty.Itisfoundthattheratiobetweenslendernessratioofintersegmentalchordmembersandthatofthewholetrussarchisthekeyfactorreflectingthatinfluence.Basedonthat,theso-calledint