钢箱梁斜拉桥成桥索力优化分析

Optimization Analysis of Cable Tensions of Dead Load State for Cable-stayed Bridge with Steel Box Girder

基于最优化理论,建立了斜拉桥索力约束优化数学模型。以斜拉桥空间有限元模型为基础,以成桥线形为目标函数,通过转化次要目标函数为约束条件等措施,采用无约束的共轭梯度法,对成桥索力进行了优化计算,并应用该法对红岛航道桥这一独塔双索面钢箱梁斜拉桥进行了索力调整计算。通过设置不同的目标函数,比较了索力调整方法的差异和适用性。计算结果表明:不同类型的斜拉桥,其索力调整的主要目标也不尽相同,钢箱梁斜拉桥的索力调整主要以成桥线形为首要目标;该优化计算方法简便有效,计算精度高,成桥线形拟合好,具有较高的实用价值。

Based on optimization theory, a mathematical model for constrained optimization of cable tensions was established. Based on spatial finite element model of cable-stayed bridge, the shape of dead load state was the objective function in this method. Unconstrained conjugate gradient optimization algorithms were applied. Through means such as modifying the minor objective function to constraint conditions, authors solved the optimization calculation of cable tensions of dead load state. The method was applied to optimization calculation of cable tensions of Hongdao Waterway Bridge which is a single pylon cable-stayed bridge with steel box girder and two cable planes. The difference and practicability of some methods about adjustment of cable tensions were compared by setting various objectives function. The results show that the primary objectives in adjustment of cable tensions are different for various types of cable-stayed bridge. The shape of dead load state is the primary objective in adjustment of cable tensions for cable stayed bridge with steel box girder. The optimization calculation method is simple, effective and precise for computing shape of dead load state and it has high practical values.