基于费用最小原则的矮塔斜拉桥索力优化研究

针对矮塔斜拉桥的特点,提出了基于拉索和预应力钢筋费用最小的索力优化方法。该方法的思路是以设计强度减去活载及其他荷载效应的应力区间,作为主梁上下缘恒载应力可行区域,引入索力和预应力的影响矩阵,利用调值原理,以拉索和预应力筋的综合费用最小为目标,来解决拉索和预应力筋的优化配置问题。用大型有限元软件ANSYS APDL 语言实现了这一功能并进行了实桥验算。研究表明:采用该方法确定的索力和预应力,与原设计相比,其费用约为原设计费用的47.9%。

OPTIMIZATION FOR CABLE-FORCE OF EXTRADOSED CABLE-STAYED BRIDGES BASED ON MINIMAL COST PRINCIPLE

According to the characteristic of extradosed cable-stayed bridges,an optimization method was put forward to minimize the cost of cables and tendons.The method follows the idea that the feasible stress range of a beam under a dead load is firstly determined by design strength subtracting the stress due to the live load and other actions.The method is aimed at minimizing the total cost of cables and tendons,realized by introducing the influence matrix of cable and tendon forces in a line with the modulating principle.The function is materialized with ANSYS APDL and the optimization theory is examined on a real bridge.The results show that the total optimized cost of cables and tendons is only 47.9% of that of the original design.