成贵铁路宜宾金沙江公铁两用桥总体设计

Overall Design of Yibin Jinshajiang River Rail-cum-Road Bridge on Chengdu-Guiyang Railway

成贵铁路宜宾金沙江公铁两用桥主桥跨径布置为(116+120+336+120+116)m,其中336 m主跨为钢箱系杆拱桥,120 m和116 m边跨为混凝土简支系杆拱桥。为解决大桥公铁合建、两岸地形高差大等技术难题,采用铁路在上、公路在下的双层桥面钢箱拱桥新结构,上、下2层桥面高差32 m,上层设4线铁路,下层设6车道城市快速路和两侧人行道。336 m主拱拱肋采用钢箱结构,在主拱上采用将公路柔性吊索内穿于铁路刚性吊杆并独立锚固于拱肋的新技术;系杆采用高强度可换型镀锌钢绞线索。

The main bridge of Yibin Jinshajiang River Rail-cum-Road Bridge on Chengdu-Guiyang Railway contains five spans of 116,120,336,120 and 116 m.Of which,the 336 m-long main span takes the form of steel box tied arch bridge,and the 120 m-and 160 m-long side spans are the concrete simply-supported tied arch bridges.To overcome the technical challenges of building rail-road bridge in the place with great elevation difference between the two river banks,the steel box arch bridge accommodating two layers of decks was recommended,with the upper deck carrying 4-track railway and the lower deck bearing the urban corridor of 6 vehicle lanes and 2 footways,and the upper and lower decks vertically distancing 32 m.The steel arch ribs of the 336 m span is of box cross-section,on which the flexible hangers of the road deck are threaded through the rigid hangers of the rail deck and independently anchored to the arch ribs,a novel hanger anchoring method.The ties comprise the replaceable high-strength galvanized steel strands.