广元嘉陵江双线特大桥拱肋安装技术

Arch Rib Installation Technology in Guangyuan-Jialing River Bridge

在新建兰渝铁路广元嘉陵江双线特大桥设计施工图中,哑铃形钢管拱肋安装采用缆索吊装和竖向转体相结合的施工方法。考虑经济性及现场施工条件,在实际施工中拟采用梁上搭设支墩的方式安装拱肋。在国内的大跨度拱辅梁桥的拱肋安装过程中,为防止梁体跨中挠度及支座处应力过大,通常于梁体跨中位置,在桥下搭设临时墩支撑梁体。本桥连续梁体竖向刚度很大,通过计算分析得出,拱肋安装过程中主梁下不设置临时墩,仅在梁上采用临时钢管支墩支撑拱肋,便能满足施工过程中主梁、拱肋、临时钢管支墩在力学特性方面的要求。

In the construction drawing of the New Lanzhou-Chongqing Railway Guangyuan-Jialing River Double-line Bridge, installation of the dumbbell-shaped steel tube arch rib adopted a method of cableway lift with vertical swivel. Considering the economical efficiency and site conditions, the arch rib was installed with buttress set up on the girders. In domestic construction of arch rib for large-span arch- auxiliary girder bridges, it is a general practice to set up temporary pier at the mid-span of the girder to prevent the mid-span displacement and bearing stresses from becoming too big. In this project, due to the large vertical rigidity of the continuous girder, calculation shows that there is no need to set up temporary pier under the girder. The use of temporary steel tube as buttress is enough to support the arch rib.