槽形梁-拱组合桥主要结构设计特点及静力分析

Design Characteristics and Static Force Analysis of Principal Structure of a Hybrid Bridge of Channel Girder and Arch

武汉市轨道交通一号线跨江汉货场主桥为连续槽形梁-拱组合桥,平面位于S形反向曲线上。由于梁体曲率的影响,梁体可能出现弯扭耦合作用,为探明该类桥梁的静力行为,分别采用空间杆系模型、实体-杆系混合模型及实体局部模型进行受力计算分析。结果表明:采用整体和局部相结合的分析方法来控制设计,具有较高的可靠性;平面杆系模型和空间杆系模型纵向应力基本吻合;由于设计活载较轻,且主梁刚度较大,梁体弯扭耦合效应不明显,且对拱肋横撑的内力影响也不大;拱-梁结合部存在一定的局部应力集中,在主梁圆弧顶部出现横向拉应力,但其分布范围较小,在此区域增强普通钢筋即可。

The main bridge of Line No.1 of Wuhan City Rail Transit spanning Jianghan Freight Yard is a hybrid bridge of continuous channel girder and arch that is laid out on the S-shape reverse curve in plane.Influenced by the curvature of the girder,the bending-torsion coupling effect might occur in the girder.To investigate the static behavior of such type of the bridge,the spatial link model,the solid and link combination model and the solid locality model are respectively used to calculate and analyze the force conditions of the bridge.The results of the calculation and analysis reveal that the design to be governed by the combined integrity and locality analysis method is of high reliability and the longitudinal stress of both the spatial link model and plane link model is basically agreeable.Because the designed load is fairly light and the main girder is rigid,the bending-torsion coupling will not be significant and the influence on the internal force of arch rib bracings will not be great.At the joint parts of the arch and girder,the concentrated stress of certain degree exists locally and in the circular arc tops of the main girder,the transverse tensile stress appears,however the distribution range of the stress is small and the tops can be reinforced by adding common reinforcement only.