斜拉桥合理成桥状态确定的一阶分析法

First Order Optimization Method for Reasonable Finished Dead Stateof Cable-stayed Bridge

本文建立了斜拉桥索力优化的非线性规划模型,其中以斜拉桥主梁和索塔的弯曲应变能为目标函数,以各斜拉索的索力为设计变量,结构的应力及索力为约束条件,采用一阶分析法进行求解,用以确定成桥合理状态的索力。在计算中,考虑大跨度斜拉桥各种几何非线性因素的影响,并列出了优化模型的具体表达式及优化过程中的关键求解策略。应用该法和空间非线性有限元分析程序分析了某千米级斜拉桥方案的合理成桥状态,计算结果表明:该方法简单、有效。

A model for nonlinear optimization programming to obtain the prestressing force of cables in cable-stayed bridge was established, in which the bending strain energy of the beams and the cable tower of the bridge is the objective function, and the cable forces are design variable, the stress of structure or the cable force is the constraint condition. In order to determine the prestressing force of the cables, the first order optimization method was used to solve the program. At the same time, the influence of various geometrical nonlinearities which are characteristics of longspan cable-stayed bridge was adopted, the idio-graphic expression of optimization model and key strategy to solve the problem were listed. This method is used to obtain set of optimal cable tensions of a thousand-meter scale cable-stayed bridge under permanent loads while the spatial nonlinear finite element program is employed, the result of analysis shows that the method is easy to apply and effective.