坝陵河大桥钢桁梁牵引控制技术研究

Research of Hauling Scheme for Steel Truss Girder of Baling River Bridge

坝陵河大桥为主跨1 088 m的单跨双铰钢桁梁悬索桥,钢桁梁采用桥面吊机由桥塔向跨中进行有铰逐次刚结架设。在有铰逐次刚结法施工过程中,由于主缆的变形较大,需将钢桁梁竖向牵引提升一定高度安装吊索,钢桁梁前端牵引量及牵引力变化较大。为确定合理的牵引方案,采用MIDAS软件计算各方案钢桁梁牵引至预定位置所需的吊索牵引力,并对钢桁梁牵引力进行优化分析。结果表明,关键节段双点牵引、一般节段单点牵引方案可较好地保证施工安全及施工进度;考虑各因素影响,按将钢桁梁牵引至对应吊索无应力长度1.05倍距离处计算的牵引量及牵引力与实测结果吻合较好,实际施工牵引力可按当前施工阶段钢桁梁前端吊索索力的1.16～1.20倍确定。

The Baling River Bridge is a single span two-hinged steel truss girder bridge with a main span 1 088 m.The truss girder of the bridge is erected by deck crane by the hinged step-by-step rigid connection method from the towers towards the midspan.In consideration that both the deformation of the main cables and variation of hauling amount and hauling forces at the front end of the girder will be great in the construction process,the steel truss girder should be vertically hauled to a certain height for the installation of suspenders.To establish a rational hauling scheme,the MIDAS software was adopted to calculate the suspender hauling force that could haul the steel truss girder to its designated location in each scheme,and also to make optimization analysis for the hauling force of steel truss girder.The results of the analysis indicate that the scheme of the two-point hauling for the critical truss blocks and the one-point hauling for the common blocks can well satisfy the construction safety and construction progress and the actual hauling forces can be determined in terms of 1.16～1.20 times of the cable forces in the suspenders at the front end of the girder at that construction stage.