基于影响矩阵的矮塔斜拉桥索力二次优化方法的研究

Research on Secondary Optimization Method of Cable Force for Extradosed Cable-stayed Bridges Based on Influence Matrix

目的针对矮塔斜拉桥索力优化问题,提出一种实用索力优化方法,为同类型桥梁优化设计提供参考依据。方法采用索力二次优化的方法,根据影响矩阵的原理,以结构整体弯曲能量最小为目标,弯矩和位移为约束条件,求得初步优化索力,再以理想成桥索力为控制目标,采用直线内插法进行正装迭代计算求得第2次优化索力。以某客专特大桥为例,利用有限元软件进行索力二次优化计算。结果对索力优化前后矮塔斜拉桥的挠度、内力以及应力结果对比可以看出,优化后无论在恒载作用下还是在主力+附加力作用下,矮塔斜拉桥整体的挠度、内力以及应力都有一定量的减少;同时主梁整体受力和线形相对比较均匀,桥梁整体结构更接近理想成桥状态。结论采用影响矩阵和直线内插法结合的二次索力优化法计算后的索力更均匀,结构状态更加满足设计和施工要求。

In order to solve the problem of cable force optimization for extradosed cable-stayed bridges,a practical cable force optimization method was proposed to provide reference for the optimization design of the same type of bridges.In this paper,the method of secondary optimization of cable force was adopted according to the principle of influence matrix,the minimum bending energy of the whole structure was taken as the goal,and the bending moment and displacement were taken as the constraint condition to obtain the initial optimization cable force.And,the method of secondary optimization of cable force was adopted according to the principle of influence matrix,the minimum bending energy of the whole structure was taken as the goal,and the bending moment and displacement were taken as the constraint condition to obtain the initial optimization cable force.Subsequently,the ideal finished bridges was taken as the control target and the linear interpolation method was used to carry out the forward iteration calculation to obtain the second optimization cable force.Finally,a passenger special bridge was taken as the example and the secondary optimization calculation of cable force was carried out by using Finife element soft.It can be seen that the overall deflection,internal force and stress of extradosed cable-stayed bridges under the constant load or main+additional force all have a certain amount of reduction after optimization.At the same time,the overall structure of bridges is closer to the ideal bridge state.The cable force calculated by the method combined with the influence matrix method and the linear interpolation method is more uniform,and the structure state more satisfies the design and construction requirements.