某钢管混凝土拱桥斜拉扣挂系统拆扣方案研究

A Study on Cable-Removing Scheme for Cable-Stay System of CFST Arch Bridge

针对某大跨径钢管混凝土(简称CFST)拱桥的斜拉扣挂系统扣索多、部分扣索角度小,调索可操作性差的实际情况,将扣索一次张拉到位、通过预拱度实现线形控制的迭代优化算法应用于拱肋吊装的线形控制和索力计算。为克服这种方法难以调整主拱肋内力和预抬高量可能偏大的缺陷,并注意到合龙前后拆除扣索的时间、顺序和方法的差异会对拱肋的线形、内力产生影响,提出修正拆扣方案,将部分扣索调整到合龙之前拆除,并对几种可行方案进行了分析和优化比选,确定了一个最佳的,更利于施工控制的方案。

Aiming at the cable-stay system of one long span CFST arch bridge that contains more cables,some of whose angles are very small,and force refinement gets bad maneuverability,the iterative optimization method with once-tension principle and alignment controlled by precambers is introduced into alignment control and cable-force calculation of erection stage.In order to overcome the limitations of the method that hard to refine the internal force of the arch rib as well as possibly too large precambers,taking notice of the influence by the time, order and method of cable-removing before and after the closure to alignment and internal force of the rib, the modified cable-removing schemes are brought forward. The new schemes assume part of the cables removed before closure, and they are analyzed and compared to each other, and then a best scheme with easier control is determined.