大跨度钢箱系杆拱桥主拱钢-混结合段受力分析

Force Analysis of Steel and Concrete Combined Segment of Main Arch for Large-span Steel Box Tied Arch Bridge

为明确大跨度钢箱系杆拱桥主拱钢-混结合段的力学性能,以西双版纳澜沧江黎明大桥为研究对象,利用有限元软件建立钢-混结合段局部精细化模型,分析钢-混结合段在不同荷载作用下构件整体及关键部位的变形与应力分布。结果表明:钢-混结合段应力传递平顺,在偏压工况作用下,结合段混凝土最大压应力为25.22 MPa,钢拱肋Von-Mises应力最大值为145.36 MPa,均小于材料容许值,满足结构设计要求;钢-混结合段内各部位变形过度均匀,混凝土拱肋最大变形为0.94 mm,钢拱肋最大变形为3.46 mm,钢-混结合段拱肋的结构刚度与变形均满足要求。在轴压工况作用下,其应力值较偏压工况模型小12.34%~16.10%,其位移值较偏压工况模型小14.29%~19.61%。通过典型工况模型计算结果,为同类型构件实体模型计算提供参考;同时,为解决钢-混结合段内关键截面存在的应力集中问题,本项目采用了锚杆交替锚固的形式,可为同类型结构的设计与施工提供参考。

In order to clarity the mechanical properties of the steel and concrete combined segment of main arch for large span steel box tied arch bridge,the Xishuangbanna Lancang River Liming Bridge was used as the research object,and the local refined model of the steel-concrete joint was established using finite element software to analyze the steel-concrete joint.Deformation and stress distribution of the whole component and key parts of the section under load.The results show that the stress transfer of the steel-concrete joint section is smooth.Under the action of eccentric loading,the maximum compressive stress of the joint section concrete is 25.22 MPa,and the maximum Von-Mises stress of the steel arch rib is 145.36 MPa,both of which are less than the allowable value of the material.Structural design requirements:the deformation of each part in the steel-concrete joint section is excessively uniform.The maximum deformation of the concrete arch rib is 0.94 mm,and the maximum deformation of the steel arch rib is 3.46 mm.The structural rigidity and deformation of the arch rib of the steel-concrete joint section meet the requirements.Under the action of axial compression,the stress value is 12.34%~16.10%smaller than that of the biased working condition model,and its displacement value is 14.29%~19.61%smaller than that of the biased working condition model.The calculation results of the typical working condition model provide a reference for the calculation of the solid model of the same type of components;at the same time,in order to solve the problem of stress concentration in the key section of the steel-concrete joint section,the project adopts the form of alternate anchor rods.Provide reference for the design and construction of the same type of structure.