中文摘要：

焊接相贯管节点连接简便，承载性能好，用钢量小，在海洋平台、桥梁、高层，尤其是大跨度网壳结构中应用广泛．空间网壳结构节点区受力复杂，目前的节点设计规范没有给出大型、异型及轴力、弯矩组合作用下焊接管节点的承载力设计方法．因此，有必要对焊接管节点在多种荷载工况下的性能进行分析．本文以北京市某空间网壳结构植物园的焊接管节点为背景，计算了节点在轴力、剪力、弯矩及扭矩组合作用下的应力、变形分布，得到了节点极限承载力，分析了节点弹性、塑性阶段刚度和承载性能的变化，并通过对比分析探讨了设置加劲肋和改变节点构造形式对节点强度和刚度的影响，对节点进行了优化．分析结果表明，贯通管节点在复杂受力条件下可能出现节点区应力集中导致局部屈服，对节点整体刚度有较大影响；在节点内部设置加劲肋能够缓解节点相贯处的应力集中，有效阻隔屈服区沿管壁方向扩展，提高节点极限承载力．

英文摘要：

The welded tubular joint is widely used in ocean platforms, bridges, high rise or long span structures due to the convenient construction, low cost and large capacity. There is a lack of clear and definite design code for the complex tubular joint subjected to axial force, moment and torsion in spatial lattice shell structure. It is necessary to analyze the performance of tubular joint under different complex load conditions. In this paper, the welded tubular joint of a Beijing spatial lattice shell structure was analyzed. The elastic and plastic performance were calculated by finite element method and two different joint types were discussed to improve the joint behavior. The results indicate that the joint stiffness is weakened by local stress concentration. The rib in joint can control the plastic zone development and increase the joint bearing capacity.