预应力混凝土连续梁优化设计

An Optimum Design of Prestressed Concrete Continuous Bridge

本文建立了一个预应力混凝土连续梁优化模式。优化设计变量包括梁截面高度和后期预加力;目标函数取混凝土及预应力钢筋造价之和;约束为截面允许应力条件。结构分析采用有限元方法,并考虑结构体系转换混凝土徐变次内力影响。应用单位预加力方法考虑预加力设计变量的次内力影响。文中算例表明,优化结果截面高度和预应力配筋比原设计降低约9％。

An optimal model of P. C. continuous bridge is given with the optimal variables the heights of cross sections and the post stage prestressing forces, the objective function the cost of both concrete and prestress tendons, and the constraints the bending stress conditions of the cross sections. The analysis of the forces due to all kinds of loading and prestressing is completed by means of the finite element method, with the consideration of the secondary forces owing to concrete creep during construction. Using the unit-prestress-force evaluation method, the influence of the secondary forces of the unknown prestress forces can be calculated. An example is given, showing that the optimal heights of sections and prestressing forces obtained are 9% less than those of the original design.