整体节点刚度对钢桁梁桥受力性能的影响

Influence of Stiffness of Integral Joints on Mechanical Properties of Steel Truss Girder Bridges

整体节点技术已广泛应用于钢桁梁桥设计,在对钢桁梁桥进行有限元分析时,通常将整体节点视为简单铰接或刚接,为了考虑整体节点刚度对钢桁梁桥受力性能,特别是对施工阶段受力性能的影响,本文以蒙华铁路跨平汝高速64m钢桁梁桥为工程背景,分别建立了节点铰接、节点刚接和考虑节点刚度影响的带刚臂空间梁单元三种有限元模型,对比分析了三种情况下,该钢桁梁桥在拖拉施工过程中的受力性能。研究表明:在钢桁梁桥拖拉施工过程中,整体节点刚度对施工阶段钢桁梁的杆件轴力和挠度影响不大;对钢桁梁的杆件端部组合应力和杆件端部次弯矩影响很大,其中对受弯构件的影响最为显著。因此,在钢桁梁桥拖拉施工过程中,应充分考虑整体节点刚度对钢桁梁桥受力性能的影响。

The integral joints are widely adopted for the design of the steel truss girder bridges and it has been usually taken as hinged or rigid connections in the finite element(FE)analysis.For considering the influence of stiffness of integral joints on the mechanical properties of the steel truss girder bridges during the construction stages,three FE models of the Cross Pingru Highway Bridge of Menghua Railway(a 64 m steel truss girder bridge),i.e.,the hinged model,the rigid model and the spatial rigid arm beam element model,are established and investigated in this study.The mechanical behavior of the steel truss grider bridges in the process of towing construction are compared and analyzed under three conditions.The research results show that the stiffness of the integral joints has little effect on the axial forces and deflections of the members of the steel truss girder in the construction stage,and has a great influence on the combined stress and the secondary bending moment at the end of the members,of which the influence on flexural members is the most significant.Therefore,the stiffness of the integral joints should be considered during the construction process of the steel truss girder bridges.