大跨连续梁桥局部顶升工艺有限元分析

The finite element analysis of Local jack-up processfor a Long-span continuous beam

局部顶升修复梁底缺陷、更换支座时,主梁的内力、线形均会发生改变,因此以一大跨连续梁桥为例,介绍了顶升时梁体内力的有限元分析方法,以确保施工过程安全。首先,建立全桥平面有限元模型获取成桥内力,并以梁体不出现拉应力为控制条件施加强迫位移,分析各墩顶升量的上限值;然后分别建立墩顶梁段、桥墩局部空间有限元模型,并施加顶升时相应的支座反力,计算、校核顶升、落梁时的安全性。

With local jacking-up to repair the defect at the bottom of the beam and replace the bearing, the internal force and line of main girder were changed, so taken a long-span continuous girder bridge as an example, the finite element analytical method of internal force when jacking-up were introduced to ensure the safety of the construction process. First of all, the plane finite element model for whole bridge is established to get the bridge internal force,and the force displacement were exerted to analyze the jacking upper limit of the pier on the control condition that the tensile stress in the beam body was zero; After that, the local space finite element model of the beam section on top of pier and the bridge pier were also established ,and the corresponding support reaction were exerted to calculate and check the safety of the jacking-up and fall.