铁路连续梁顶升法更换支座技术方案研究

Research on Technical Scheme of Railway Continuous Girder Bearing Replacement by Jacking Method

以一座在建(48+80+48)m铁路连续梁桥3#墩的球型支座为例,分析支座变形原因,提出单墩顶升梁体更换支座的整治方案。采用数值模拟方法分析了不同顶升高度时的梁体应力,根据计算结果确定支座更换时梁体的安全顶升高度。结果表明:支座下座板异常变形是由砂浆垫层局部区域支承强度不足引起;在3#墩处顶升梁体对相邻两侧梁体应力影响较大;施加二期恒载前后在3#墩处顶升5~30 mm时梁体顶底板应力均满足规范要求,建议梁体顶升高度取20 mm。

Taking the spherical bearing of a(48+80+48)m railway continuous girder bridge 3#pier under construction as an example,the causes of bearing deformation were analyzed,the treatment scheme of jacking girder of single pier and replacing the bearing was put forward.The girder stresses at different jacking heights were analyzed by numerical simulation method,and the safe jacking height of the girder was determined according to the calculation results.The results show that the abnormal deformation of the bottom slab under the bearing is caused by the insufficient support strength in the local area of the mortar cushion.Jacking girder at 3#pier has a great influence on the stress of adjacent girders on both sides.Before and after applying secondary dead load,when the 3#pier is jacked for 5~30 mm,the stresses of the top and bottom slabs of the girder meet the specification requirements.It is recommended that the jacking height of the girder be 20 mm.