大跨度三塔结合梁斜拉桥边跨强制合龙施工技术

Construction Technology for Compulsory Side Span Closure in Large-span Triple-pylon Steel-concrete Composite Girder Cable-stayed Bridge

武汉二七长江大桥主桥为三塔结合梁斜拉桥,主跨主梁由工字钢组合梁及预制桥面板结合,辅助墩与过渡墩间边跨为预应力混凝土主梁。全桥共有两个边跨合龙段,采用了顶推强制边跨合龙施工方案,通过顶撑系统将合龙口增大,吊装合龙段主梁后再缩小合龙口,实现主梁合龙。与常规工艺相比,成桥状态更符合设计理念,施工不受环境条件限制。

The Wuhan Erqi Yangtze River Bridge is a triple-pylon steel-concrete composite girder cable-stayed bridge. Its primary girder in its main span was constructed using steel-concrete composite Girder made with I beams and precast concrete deck while the pre-stressed concrete primary girder was utilized in the side spans between the auxiliary piers and transition piers. There are two side span closures in the entire bridge section and forced closure by incremental launching was adopted during the construction. First, the closure was expanded using the incremental launching system, and then it was contracted once the primary girder for the closure was installed. This method accords more with the design philosophy than any other meth- ods and is free from interferences generated by the construction environment.