支点高差对多跨钢桁梁落梁施工应力影响分析

为明确拖拉落梁施工时支点高差对钢桁梁杆件应力的影响,以一座多跨简支钢桁梁桥为工程背景,利用MIDAS/Civil软件建立空间模型进行数值模拟。研究结果表明:两跨端部主桁出现支点高差引起的钢桁梁杆件应力呈线性变化;支点高差对钢桁梁端斜杆应力影响最为明显;通过调整钢桁梁首尾端支点高差的方法可实现临时连接水平杆件的零应力拆解;落梁作业时,不同步落梁产生的杆件应力大体呈现线性增加的趋势,其中,对角不同步落梁对杆件应力影响最大。

Analysis of Influence of Fulcrum Height Difference on Construction Stress of Multi-span Steel Truss Girder

In order to clarify the influence of the fulcrum height difference on the stress of steel truss girder during the construction of dragging and lowering girder,taking a multi-span simply supported steel truss bridge as the engineering background,the spatial model was established by MIDAS/Civil software for numerical simulation.The research results show that the stress of steel truss girder caused by the fulcrum height difference at the end of two spans is linear,and the influence of fulcrum height difference on inclined member stress of steel truss girder is the most significant.It is obvious that the zero stress disassembly of the temporary connecting horizontal members can be realized by adjusting the fulcrum height difference at the head and tail of the steel truss girder.During the girder lowering operation,the member stress caused by different steps of lowering girder generally presents a linear increasing trend,among which,the diagonal asynchronous girder lowering has the greatest impact on the member stress.