基于粒子群算法的异形斜拉桥成桥索力优化

Cable Force Optimization of Special-shaped Cable-stayed Bridge Based on Particle Swarm Algorithm

异形斜拉桥的结构比较复杂,受力特点与常规斜拉桥不同,传统的索力优化方法存在不适用或优化过程烦琐的问题。粒子群算法可高效、便捷地得到合理的成桥状态,实现索力优化的自动化和智能化操作。为验证结合粒子群算法的索力优化方法的可行性,以某异形斜拉桥项目为依托,利用Midas Civil软件建立三维有限元模型,以最小势能为目标函数,结合粒子群算法自主编写MATLAB程序,对桥梁成桥阶段状态的索力进行优化,并将该方法与传统索力优化方法进行对比。结果表明:传统的索力优化方法不适用于异形斜拉桥,传统的最小弯曲能量法只减小主梁和桥塔的刚度,无法得到可行性结果,虽然添加约束条件后可得到斜拉桥的合理成桥状态,但操作过程烦琐;基于粒子群算法的索力优化方法可更大程度利用斜拉索,获得合理的成桥状态,同时优化过程也更加简便、高效。

The structure of special-shaped cable-stayed bridge is complex,and the stress feature is different from that of conventional cable-stayed bridge,so the traditional method of cable force optimization is not applicable or the optimization process is tedious.Particle swarm algorithm can obtain reasonable bridge state efficiently and conveniently,realizing the automation and intelligence of cable force optimization.In order to verify the feasibility of the cable force optimization method combined with particle swarm algorithm,a three-dimensional finite element model was established on the background of a special-shaped cable-stayed bridge project with the target of minimum potential energy.A MATLAB program was written with particle swarm algorithm to optimize the cable force at the completion stage of the bridge,and compared with the traditional cable force optimization method.The results show that the traditional cable force optimization method is not applicable to the special-shaped cable-stayed bridge.The traditional minimum bending energy method which only reduces the stiffness of the main beam and bridge tower cannot get the feasible result.Although adding constrains can get a reasonable state of bridge formation,the operation process is complicated.The cable-force optimization method based on particle swarm optimization can obtain the reasonable bridge state by using the cable to a greater extent,and the optimization process is simpler and more efficient.