基于无应力状态法的钢箱梁斜拉桥成桥目标线形的实现

Realization of Target Geometric Shapes of Completed Bridge of Steel Box Girder Cable-Stayed Bridge Based on Unstressed State Method

针对钢箱梁斜拉桥成桥目标线形的实现,以厦漳跨海大桥北汊主桥为例,提出基于无应力状态控制法理论的主梁预拱度取值、制造尺寸确定、预拼装线形计算及悬臂拼装控制方法。该桥为多跨连续半飘浮体系钢箱梁斜拉桥,采用桥梁结构设计系统SCDS2011建立桥梁有限元模型,求得钢箱梁设计预拱度;钢箱梁制造尺寸确定时考虑竖曲线和设计预拱度及梁体轴向压缩、弯矩转角的影响;以预拼装线形为基础计算得出每节段前、后控制点的坐标值进行预拼装;在钢箱梁悬臂拼装过程中进行线形控制时,考虑安装阶段的计算挠度及成桥状态与设计预拱线形的高程差。事实证明,采用该方法对钢箱梁斜拉桥进行成桥目标线形的控制取得了良好的施工精度。

In view of realization of the target geometric shapes of the completed bridge of steel box girder cable-stayed bridge, the main bridge of the north bridge of Xiazhang Sea-Crossing Bridge was cited as an example and a method for the value selection of precambering, determination of manufacturing dimensions, calculation of geometric shape of preassembling and control of cantilever assembling of the main girder of the bridge based on the unstressed state method theory was proposed. The cited bridge is a multi-span semi-floating system continuous steel box girder cable-stayed bridge and the bridge structural design software SCD82011 was used to set up the finite element model for the bridge and to acquire the designed precambering of the box girder. In the determination of the manufacturing dimensions, the influences of the vertical curve, designed precambering, axial compression and moment rotation angles of the girder were considered and according to the geometric shape of preassembling, the coordinate values of the front and rear control points of each girder block were calculated and the blocks were then preassembled. The geometric shape of the steel box girder was controlled in the process of cantilever assembling and at the same time, the calculated deflection of the girder at the assembling stage and the elevation differences between the completed bridge status and the designed geometric shape of preeambering were taken into account. Facts prove that the control of the target geometric shapes of the completed bridge of the steel box girder cable-stayed bridge, using the method as described, can achieve good construction precision.