自锚式悬索桥施工过程模拟分析

基于UL列式的虚功增量方程,推导出了适用于悬索桥缆索几何非线性分析的两节点悬链线索单元,并在此基础上,提出了一套模拟自锚式悬索桥施工全过程的精细迭代算法.以佛山市平胜大桥独塔自锚式悬索桥(主跨350 m)为例,对加劲梁的施工拟采用2种模拟方法,方法1为“等效集中力法”,即把加劲梁的重量等化为集中力作用在主缆上,而方法2则是考虑加劲梁的重量由主缆和加劲梁共同承担.应用自编程序,分别对其进行了施工过程的模拟计算,得到了各自的鞍座及索夹偏位、主缆初始线形等架设参数以及一期恒载、二期恒载状态下的结构几何形状及内力.通过对2种施工模拟方法的比较分析得出,方法1具有较好的可行性.

An Analysis of Construction Stages Simulation for Self-Anchored Suspension Bridges

Based on the virtual work increment equation of updated Lagrangian formulation,a two-node catenary cable element for the geometrical non-linear analysis of suspension bridge's main cable was developed.Furthermore a fine iterative method of simulating construction stages of self-anchored suspension bridge was investigated.Two methods were put forward to simulate the construction of the main girder of Pingsheng Bridge in Foshan,a single-tower self-anchored suspension bridge with a main span of 350 m,one of which is "equivalent-concentrate-force method",that is,the weight of the main girder is simplified with concentrate forces to act on the main cable,and the other of which supposes that the weight of the main girder acts on both the main cable and the main girder.The construction stage simulations were completed in the author's program.Erection-parameters such as the offsets of the saddle and the cable clips,the initial geometry of the main cable were calculated.Also,the geometry and the inner force of suspension bridges under the first dead load and the second dead load were found.By comparison,the construction feasibilities of the two methods were demonstrated and the first method was of better feasibility than the second method.