下承式尼尔森钢管混凝土提篮拱拱脚定位施工研究

Positioning Research of the Arch Foot About the Through Nelson Concrete-filled Steel Tube X-arch Bridge

下承式尼尔森钢管混凝土提篮拱造型优美,跨度大,在铁路、公路桥梁中得到广泛应用,比平行拱横向稳定性好,可是拱肋施工定位难度大。针对下承式尼尔森钢管混凝土提篮拱所具有的以上特点,结合包河大道特大桥拱脚安装工程实例,介绍了拱脚定位的关键技术,包括悬链线方程、拱肋控制点坐标的空间变换方法,得出拱脚控制点定位坐标与悬链线方程和内倾角度之间的关系式和施工注意事项,并给出评估钢管拱肋对接安装时错边量的计算公式。

The through Nelson concrete-filled steel tube basket bowstring arch bridge with elegant shape and large span is widely used in the railway and road bridges,of which lateral stability is better than the parallel arch,but it is very difficult for arch rib position.According to the characteristics of the through Nelson concrete-filled steel tube X-arch bridge,based on the installation example of the arch foot,the author introduces the key technology of arch foot location,including catenary equation,space transformation method of the control point coordinate.Thus the relation is obtained among the control points coordinates of the arch foot and the catenary equation and leaning angle,as well as construction cautions.The formula is showed to evaluate edge offset during abutting joint with steel tube arch rib.