下承式系杆拱桥施工阶段受力特性研究

Study on Mechanical Characteristics of Through Tied-arch Bridge at Construction Stage

为研究某下承式系杆拱桥在施工阶段的最不利受力状态,采用空间有限元分析软件Midascivil,模拟实际施工流程,对其施工阶段的受力特性进行计算与分析。介绍了该桥在施工阶段有限元模型的建模要点,分析了吊杆索力、拱肋的应力、变形等随施工阶段变化的规律,针对薄弱部位给出了相应改善建议。结果表明,由于拱肋外倾,内侧吊杆索力远远大于外侧吊杆索力,且最大值均发生在最终施工阶段;在最初施工阶段,拱脚处截面左缘受拉、右缘受压,拱顶处截面左缘受压、右缘受拉;拱肋横向位移对拱肋的变形起控制作用,大于竖向位移的影响。分析计算结果可以为本桥及类似拱桥的施工分析提供参考。

In order to study the most adverse stress state of a through tied arch bridge at construction stage,the spatial finite element analysis software Midas civil is used to simulate the actual construction process and to calculate and analyze the mechanical characteristics of the construction stage.The key points of the finite element model of the bridge during the construction stage are introduced.The cable force of suspenders,the stress and the deformation of the arch ribs with the change of the construction stage are analyzed,and some suggestions for improving the weak parts are given.The results show that the cable force of medial suspender is far greater than that of the lateral suspender due to the extraversion of the arch rib,and the maximum value occurs at the final construction stage.In the initial construction stage,the left edge of arch foot section is tensioned and the right edge is compressed;the left edge of vault section is compressed and the right edge is tensioned.The transverse displacement of the arch rib has a controlling effect on the deformation of the arch rib,which is greater than the vertical displacement.The analysis and calculation results can provide reference for the construction analysis of this bridge and similar arch bridges.