大跨度钢管混凝土拱桥安装线形控制方法研究

Study of Alignment Control Method for Installation of Arch Ribs of Long Span CFST Arch Bridge

为解决大跨度钢管混凝土拱桥钢管拱架设过程中存在的索力偏差大、线形调整难、索力与标高不匹配等问题,提出"宁高勿低、宁静勿动"的线形控制原则和一种新的扣索索力计算方法。以某主跨360m铁路钢管混凝土提篮拱桥为例,对比新方法的计算索力与实际张拉索力的差异,研究各节段在架设过程中的线形变化及预抬高对节间焊缝宽度的影响。研究结果及实际工程表明,该线形控制原则和索力计算方法具有较高的索力计算精度,能够保证节段重量由缆索吊承载向扣索受力的顺利转换,满足成拱线形光滑的要求,且可实现扣索一次性张拉达到线形控制目的。

To resolve the problems that the fastening stay force deviations are great, the a lignment adjustment of the arch ribs is difficult and the stay forces and elevation do not match in the installation process of the steel tube arch ribs of long span concretefilled steel tube （CFST） arch bridge, the alignment control principle of ＂keeping the installed blocks of the arch ribs high rather than low and keeping the blocks stationary rather than movable＂ and a kind of the new cal culation method for the stay forces were developed. A railway CFST basket handle arch bridge with a main span 360 m was taken as an example, the differences between the stay forces calculat ed according to the developed new method and the actual tensioned stay forces in the installation were compared and the changes of the alignment of the arch ribs and the influences of preraising of the arch rib blocks on the welding seam width of the blocks in the installation of the different blocks were studied. The results of the study and the actual installation indicate that the align ment control principle and the new calculation method have high calculation precision of the stay forces, can ensure the favorable transformation of the block weight carried by the cable crane to the weight to be carried by the fastening stays, can satisfy the requirement for the smooth align ment of the completed arch ribs and moreover, can achieve the alignment control goal of tensio ning the stays in one time.