大跨度悬索桥施工过程加劲梁临时连接的有限元模拟研究

Finite element simulation of temporary connection between stiffening girder segments during erection for long-span suspension bridges

在悬索桥施工过程中,加劲梁段之间的临时连接在一定程度上削弱主梁的刚度,准确模拟临时连接是进行悬索桥施工阶段分析的关键。基于修正倒拆法确定不同施工阶段结构的线型和内力,采用梁单元模拟法、平均刚度法、临时铰接法来模拟施工过程中的加劲梁临时连接。通过有限元计算,对比研究大跨度悬索桥施工阶段中动力特性的变化规律,讨论不同模拟方法对施工阶段中扭弯频率比及颤振临界风速的影响。研究结果表明,采用临时铰接法计算出的扭弯频率比及颤振临界风速偏低,采用其他2种方法计算出的扭弯频率比和颤振临界风速比较接近。

To some extent,temporary connections between stiffening girder segments reduce the stiffness of stiffening girder. It is necessary to simulate the temporary connections precisely for analysis of long-span suspension bridges during erection. Based on a modified backward analysis method,the structure shape and internal force at each erection phase are determined. Three methods are used to simulate the temporary connection,including beam simulating method,average stiffness method and temporary hinge method. Some comparative study is performed for the variation of dynamic characteristics with erection percentage. The effect on the ratio of torsional to vertical frequency and the flutter critical wind speed,resulting from different simulation methods in the construction period,are also discussed. It is shown that the ratio of torsional to vertical frequency and flutter critical wind speed are lower,the calculation results by other two methods are close.