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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。
The static tests of two circular arch truss arch models with circular arc and span of 10 m are carried out under uniform loads across the whole span. The out-of-plane stability of the flat steel tube truss arch is analyzed. An out-of-plane rotating spring unit and a horizontal displacement spring unit are introduced to establish a spring-rod finite element model, and the test model is subjected to nonlinear finite element analysis. The results of the test and the finite element analysis show that the flat steel tube truss arch with no out-of-plane support on the lower chord has lateral buckling instability of the upper and lower chord under compression and causes the overall out-of-plane buckling failure. The out-of-plane rotational stiffness of the intersecting nodes has a significant effect on the out-of-plane stability of the test model. The results of spring-rod finite element analysis are in good agreement with the experimental results, which can provide reference for the out-of-plane stability analysis and design of the same type of structures.