斜拉桥索力优化的强次可行SQP法及地震分析

Cable tension optimization based on strongly feasible sequential quadratic programming method and seismic analysis of cable-stayed bridge

为研究复杂大跨度斜拉桥索力优化问题及探讨拉索索力对斜拉桥地震响应的影响,提出采用新型强次可行序列二次规划算法(SQP),建立非线性数学规划模型,进行自动搜索求解合理成桥索力,并以不同索力工况进行地震动力数值模拟分析.结论表明:新型强次可行SQP法适用于复杂的大型斜拉桥索力优化问题,计算结果与设计索力吻合良好,成桥状态主梁弯矩分布均匀,主塔接近轴压受力,结构变形远小于规范限制.地震作用下,优化的拉索索力可有效改善主梁弯矩分布不均匀现象,限制主梁跨中纵向变形和主塔横向变形,使整个结构在地震中更加安全.

In order to study the cable tension optimization problem of complex and long span cable stayed bridges and to study the influence of cable tension on seismic response of cable stayed bridges, a new strongly sub feasible SQP（Sequential Quadratic Programming） algorithm is proposed to establish a nonlinear mathematical programming model for automatic searching optimal cable forces, and the seismic dynamic analysis is carried out under different conditions. The results show that the new method is suitable for the optimization of cable tensions. The optimal cable tensions are in good agreement with the designed cable forces, and the bending moment distribution of the main girder is uniform. The main tower is mainly subjected to axial pressure, the bottom moment of the tower is small, and the deformations of the structure are much smaller than the standard limit values. The optimal cable tensions can effectively change the uneven distribution of the bending moments of the main beam, and reduce the longitudinal deformations of the main girder and the transverse deformations of the main tower so that the whole structure will be more secure under earthquake action.