公安长江大桥主塔上横梁施工技术

Construction Techniques for Upper Cross Girder of Pylons of the Gong’an Yangtze River Bridge

公安长江大桥主塔为H型塔,主塔塔柱采用爬模施工,上横梁采用支架塔梁异步现浇施工,横梁支架为桁架式结构,桁架两端支承于主塔内侧面预装的钢牛腿上,主塔上横梁体积大。由于支架位于高空,支架安装、预压难度大、风险高,采用地面自平衡加载模拟预压,然后塔吊单片整体吊装桁架安装,变高空作业为地面作业,既能实测支架承载后变形量,又能检验支架的实际承载能力,安全性好,是一种非常规情况下支架预压和横梁施工较为经济、合理的方案。

The pylons of the Gong’an Yangtse River Bridge with "H" shape pylons were constructed by the climbing shuttering. The structure of the cross girder support is truss and the two ends of the truss are supported on the steel bracket which is pre-installed on the side of the py-lons. Because the volume of upper cross girder is huge and the support is heavy, it is difficult and risky to install and preloading. Self-balancing method is used to simulate preloading on the ground. Then installing the truss one by one by the tower crane turns install construction in the high into on ground. It not only can measure the deformation of the support after bearing, but also can verify the actual carrying capacity of the bracket because it's an economic and reasonable scheme under unconventional conditions.