平面钢管桁架拱平面外稳定试验研究与有限元分析

Test study and FEA on out-of-plane stability of planar tubular truss-arches

对2个跨度为10 m的圆弧形平面圆钢管桁架拱模型进行全跨均布荷载作用下的静力试验研究,分析了平面钢管桁架拱的平面外稳定承载力。引入平面外转动弹簧单元、水平位移弹簧单元,建立弹簧-杆系有限元模型,对试验模型进行非线性有限元分析。试验和有限元分析结果表明:下弦杆无平面外支撑的平面钢管桁架拱,在极限状态时,受压上、下弦杆发生侧向弯曲失稳,并引起整体平面外弯曲失稳破坏;圆钢管相贯节点的平面外转动刚度对试验模型的平面外稳定承载力影响显著。弹簧-杆系有限元分析结果与试验结果较为吻合,可为同类型结构的平面外稳定分析、设计提供参考。

Static tests of two 10-meter span circular planar tubular truss-arches models were carried out to study the out-of-plane stability capacity under full span loading. By introducing out-of-plane rotation spring element of CHS joints and displacement spring element of support, nonlinear spring-beam finite element model was build to analyze the out-of-plane stability capacity of planar tubular truss-arches. Tests and FEA results show that, the ultimate state of planar tubular truss-arches without out-of-plane bracings on bottom chords is out-of-plane instability induced by lateral flexure of compression chords, bearing capacity is significantly effected by out-of-plane rotation stiffness of CHS joints. Nonlinear spring-beam FEA results agree well with the test results, and the finite element model can give reference for out-of-plane stability analysis and design of planar tubular truss-arches.