大跨预应力钢桁架优化设计和最优造价曲线研究

以钢桁架结构的造价为目标函数 ,采用罚函数的方法 ,对几种高度的 42m跨平行弦平面桁架、平行弦预应力平面桁架、倒三角形立体桁架、倒三角形预应力立体桁架进行优化设计。通过对计算模型的大量优化结果研究 ,提出了最优造价曲线的概念 ,描绘出几种高度的 42m跨平行弦预应力平面桁架和倒三角形预应力立体桁架在不同预拉力值下的最优造价曲线、几种高度的 42m跨平行弦平面桁架及倒三角形立体桁架的最优造价曲线 ,并对这些曲线的特性作了分析。最后通过示例说明这些曲线可以帮助建筑或工艺专业进行建筑结构选型 ,也可作为建筑经济专业报价和审计之用

OPTIMAL DESIGN AND COST-CURVE STUDY FOR LARGE-SPAN PRESTRESSED STEEL TRUSSES

By using a sequential uncontrained minimization technique with the costs of steel trusses as the objective functions,Optimal design of a 42 metre long steel truss is conducted,considering several heights and verions forms,suchas plane steel trusses with parallel cords, plane prestressed steel trusses with parallel cords, nabla-shaped space steel trusses and nabla-shaped space prestressed steel trusses. By studying a large amount of results of computational models, a new concept of optimal cost curve is proposed. The optimal cost curves of all computational models are drafted and the characteristics of these curves are analyzed.Examples are prorided to help explain the usage of these curves, especially for architecture and technology specialty to select structure types and architecture economics specialty to quote and audit.