成贵铁路鸭池河特大桥拱肋架设二次横移技术

成贵铁路鸭池河特大桥主桥为主跨436m的中承式钢桁-混凝土结合拱桥,其钢拱肋采用斜拉扣挂法进行节段悬臂拼装施工。1～4号钢拱肋节段在拼装平台组拼后,直接利用缆索吊机吊装到位;因作业空间限制,5～13号钢拱肋节段吊装时采用二次横移技术施工。在组装及起吊平台同岸侧的两拱脚中间设置二次横移平台,平台顶面高于该处拱肋,并在平台顶面设置横移系统。施工时,首先利用缆索吊机从上、下游拱肋之间起吊拱肋节段至已架设拱肋上方,再利用缆索吊机将其运至二次横移平台上方,通过横移系统将拱肋节段横移至与待安装部位等边距位置,并同步移动缆索吊机索鞍及主索,最后利用缆索吊机将拱肋节段纵移至待安装位置后安装。

Techniques for Secondary Transverse Movement in Erecting Arch Rib of Main Bridge of Guizhou Yachi River Bridge on Chengdu-Guiyang Railway

The main bridge of Guizhou Yachi River Bridge on Chengdu-Guiyang Railway, having a main span of 436 m, is an arch bridge with a composite structure of half-through steel truss and concrete. The steel arch ribs are constructed with assembling cantilevered segments by using a cable-stayed buckle method. Segments of No.1- No.4 steel arch ribs assembled on assembling platform are directly hoisted to the design position by using cable crane. Segments of No.5- No.13 are constructed by the secondary transverse movement technique due to the constraints of operational space. A secondary transverse platform is set between the two arch feet on the same bank of the assembling and lifting platform. The top of the platform is higher than the arch rib, and a transverse system is installed on the top of the platform. During the construction, the segments of arch ribs are lifted between upper and lower arch ribs by a cable crane to the top of the erected arch ribs, then are transported to the upper part of the secondary transverse platform by the cable crane, and are transversely moved to the position at an equilateral distance from the position to be installed by the transverse movement system. Thereafter, the cable saddle and main cable of cable crane are synchronously moved;finally, the segments of arch ribs are longitudinally moved to the position to be installed by cable crane.