型钢桁架腹杆端部扩大节点的力学讨论

Discussion on the Mechanical Properties of the End Expanding Connection of Diagonal Members in Steel Truss Structures

采用H形或箱形截面作为弦杆和腹杆的桁架形式被广泛用于大跨度结构中。其腹杆与弦杆的连接节点一般采用一种腹杆端部扩大的连接形式。需要注意的是,端部扩大节点看似能减小应力集中,但仔细分析就会发现,此类节点的力学性能并不合理。分析了型钢桁架中端部扩大节点的受力机理,并采用有限元分析软件ANSYS对腹杆端部扩大节点进行了弹塑性分析。分析结果显示,此类节点力学上存在不合理性。进一步提出了较为合理的节点形式供结构工程师参考。

H-shaped and box-shaped sections are widely used in large-span truss structures as chord and diagonal members.Normally an end expanding connection is applied when a diagonal member is connected to a chord member.These end expanding connections may reduce the stress concentration.However,based on detailed analysis,the mechanical properties of these connections are not reasonable.This paper presents force mechanism of the end expanding joints.Elastic-plastic analysis is carried out to model these connections by using finite element analysis software ANSYS.The study results indicate that these connections are irrational. Then some more advanced connections are recommended for structural engineers.