The load-carrying capacity of plane tubular trusses is governed by the out-of-plane flexur-al buckling of the compression main tubes that have no bracings. An imprecise load-carrying capaci-ty will be concluded without taking the effect of joint stiffness into account. In order to analyze the effect of every component of joint stiffness, nonlinear finite element models of plane tubular trusses based on space beam and spring elements are constructed and parameter study on load-carrying ca-pacity of these models are carried out. The results show that the load-carrying capacity is affected obviously by the out-of-plane rotation stiffness. However, the influence of the in-plane rotation and torsion stiffness is small and could be neglected. Therefore, the effect of the out-of-plane rotation stiffness must be taken into account in order to get precise conclusion in the stability analysis of plane tubular trusses.%平面外失稳是平面钢管桁架受压主管在荷载作用下的主要破坏形式之一.在稳定验算过程中,如果不考虑相贯节点转动刚度的影响,对于受压主管无支撑的平面桁架将得到一个不精确的面外稳定承载力.为了评估节点转动刚度各分量的影响,对平面钢管桁架建立带连接单元的杆系非线性有限元分析模型,并对有限元模型的稳定承载力进行了节点刚度参数分析.分析结果表明,节点面外转动刚度对于面外稳定承载力影响显著,而节点面内转动刚度及扭转刚度影响很小,对平面钢管桁架进行稳定分析时,必须考虑节点面外转动刚度的影响,才能得到较为精确的分析结果.
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