钢板组合梁桥结构受力分析

Analysis of Mechanical Property of Steel Plate Composite Girder Bridge

为了解钢板组合梁桥施工过程的力学行为,以长沙湘府路快速化改造工程主线高架桥为背景,采用MIDAS Civil软件建立4×30 m钢板组合连续梁桥空间有限元模型,对各施工阶段进行分析,并研究运营阶段混凝土收缩徐变、温度作用对结构受力的影响。结果表明:施工过程中结构应力满足规范要求;混凝土桥面板的收缩徐变使组合梁持续下挠,组合梁截面的内力、应力发生重分布,收缩徐变引起的变形量和内力、应力变化量在总量中所占比例不容忽视,设计时必须考虑其影响;体系温度变化、梯度温度作用对组合梁的线形影响较小,组合梁梯度温度效应明显大于体系温度效应,且温度应力增量不容忽视,必须合理分析温度作用对结构安全性的影响。

To examine the mechanical property of the steel plate composite girder bridge in the construction process,the viaduct on the main line of Xiangfu Road Upgrading Project in Changsha is taken as a case.The spatial finite element model of the steel plate composite girder bridge with four equal spans of 30 m was built by MIDAS Civil,to analyze the construction stages and study the influence of concrete shrinkage and creep and thermal effect on the load bearing behavior of the structure.The results show that the stresses in the construction stages can meet the code requirements.The shrinkage and creep of concrete slabs cause continuing deflection of the composite girder,resulting in redistribution of internal forces and stresses in the cross section of the composite girder.Therefore,the proportion of variation amount of deformation,internal forces and stresses caused by shrinkage and creep should not be ignored in the total amount,the influence of which must be considered in design.Systematic temperature variation and temperature gradients exert minimal influence on the geometry of the composite girder,but the effect of temperature gradients is more distinctive than systematic temperature variation.The increment of temperature stresses should not be ignored and the action of temperature effect on safety of the structure needs rational analysis.