超大跨度斜拉桥横桥向恒载不对称结构合理施工状态研究

Study on Reasonable Construction State of Super Long-span Cable-stayed Bridge with Transverse Asymmetric Dead Load

为研究横桥向恒载不对称结构力学行为,以常泰过江通道主航道桥为工程背景,采用MIDAS软件建立空间杆系全桥有限元模型。采用施加不对称索力的方法来控制主梁扭转变形,并通过影响矩阵法优化成桥索力,实现“塔直梁平”的理想成桥目标状态。运用无应力状态法,详细模拟桥梁悬臂施工过程,对斜拉桥结构的分阶段形成作正装非线性计算,确定斜拉桥合理施工状态。分析结果表明:通过调整横桥向的不对称索力可以得到大桥的理想成桥线形,采用两次张拉的施工方案中桥梁结构未发生明显的扭转和空间变形,合龙状态良好;考虑安装过程得到的成桥线形和索力与理想成桥目标状态一致。

To study the mechanical behaviors of the bridge with transverse asymmetric dead load,MIDAS software was used to establish the finite element model of the spatial truss system for the full bridge with main channel bridge of the Changtai River Crossing Channel as engineering background.The torsional deformation of the main girder was controlled by applying asymmetric cable force,and the cable force of completed bridge was optimized by the influence matrix method to realize the ideal completed bridge state“straight tower and flat girder”.The unstressed state method was used to simulate the cantilever construction process,and the non-linear calculation of the cable-stayed bridge structure formed in stages was performed to determine the reasonable construction state of the cable-stayed bridge.The results show that the ideal completed bridge geometric shape can be obtained by adjusting the transverse asymmetric cable forces,and there was no significant torsional and spatial deformation for bridge structure in the construction scheme with tensioning twice and the closing state was good.The completed bridge geometric shape and cable forces obtained in the installation process were considered to be consistent with the ideal completed bridge state.