钢管混凝土拱桥吊装过程的最优化计算分析

Calculation method for optimizing the installation process of concrete-filled steel tube arch bridge

以在建的主跨460 m的中承式钢管混凝土拱桥———巫峡长江大桥为例,在综合考虑拉索的垂度效应与结构几何非线性影响的基础上,采用一阶最优化计算方法来确定拱桥的合理施工状态。以成桥后拱肋的线形为目标函数,施工中拱肋节段的预转折角为设计变量,利用施工优化的原理,直接建立施工期结构状态可测变量与成桥状态目标函数之间的关系。通过对目标函数的最优化处理,求出各施工阶段的扣索索力和拱肋吊装高度,模拟了钢管拱肋的拼装过程。计算结果表明:将最优化计算理论引入拱桥的施工过程计算中是可行的,结果也是合理的。

Authors introduce the optimization theory and method into the calculation of erecting arch ribs. The first order optimization method is used to determine the rational construction state of a concrete-filled steel tube arch bridge which is a 460 m span bridge in Wu Gorge of Yangtze River under construction in China. Nonlinear influences caused by cable sag and structure are included in this method. Using the construction optimization theory, the relationship of structural measurable variable in construction state and objective function in the finished dead state is theorized where the arch rib elevation error is the objective function and the prearranged angles of ribs are the design variable. By the optimization calculation, the cables force and the prearranged height of arch ribs during construction are obtained, and the actual construction process of arch ribs installation is simulated. The result shows that this method is effective and feasible.