大跨拱桥吊装施工线形控制计算方法研究

针对大跨度拱桥缆索吊装施工线形控制计算中有关模型建立、确定目标控制线形和吊装过程模拟计算等问题进行了研究.分别考虑吊装系统中各构件之间相互作用的复杂关系及其对结构的影响程度,根据最终成桥线形,采用倒拆法确定目标控制线形;根据设计线形和所有恒载、活载变形,确定预制时的无应力长度.针对拱圈预制节段的两种不同安装方法,提出分别采用正装迭代法和刚性支承-弹性索法计算拱肋安装坐标及扣索索力.通过工程实例分析表明.两种方法计算的扣索索力很接近,但安装坐标相差很大.施工控制结果表明,采用本文方法进行控制的拱肋线形与设计线形吻合良好.

Study on Computation Method of Geometric Configuration Control for Long-span Arch Bridges Constructed by Cable-hoisting

Some problems involved in the geometric configuration controlling calculation of long-span arch bridges erected by cable-hoisting method were studied, such as computational modeling, objective geometric configuration for control and simulating computation of the lifting and installing process. According to the final geometric eonfiguration, with consideration of the complexity of the interaction of each part of the cable-installing system and their influences on the structure, the objective geometric configuration was determined by inversely-disassembling method. According to the preliminary designed geometric configuration and all deflections induced by permanent loads and live loads, the length of each unstressed precast segment was determined. In light of the two installing methods of precast arch segments in construction, the method of iterative forward analysis and the method of rigid support and elastic cable were submitted respectively for the computation of installing coordinates and buckling-cable forces. The analysis result of a practical ease indicates that the buckling-cable forces are very close by nsing the two approaches, while the installing coordinates differ much from each other. The obtained geometric configuration by the proposed method agrees quite well with the designed one.