预应力钢管混凝土组合桁架优化分析与方案研究

Optimization analysis and scheme research of the prestressed concrete filled steel tubular combinatorial truss

以大跨度输煤栈桥上部通廊为研究对象,提出等效挠度比作为目标函数,采用改进满应力法,以腹杆形式和撑杆布置方式作为优化变量,综合考虑结构布置方案对挠跨比和用钢量的影响,对70m和80m跨度预应力钢管混凝土组合桁架栈桥进行优化分析和方案比较。结果表明,大跨度预应力钢管混凝土组合桁架采用人字式腹杆的经济性效益最好,采用多撑点廓外布索的跨中挠度和等效挠度比较小,经济性明显提高。本文提出采用等效挠度比作为目标函数的优化方法计算简单、操作方便,可适用于其他预应力钢结构优化分析与方案比较。

The study subject in this paper is the propylaea the top of long span coal transporting trestle. Adopting modified full stress method to make optimization analysis and scheme comparison for the pre - stressed encased con- crete circular steel - pipe truss bridges, whose span is 70m - 80m. Equivalent deflection ratio is setting as the ob- jective function, and web member system and cables arrangement form are setting as optimization variables, consid- ering the influence of the structure arrangement scheme on deflection - span ratio and the amount of steel. The re- sults show that the herringbone type web member system is the most economic method for large -span prestressed steel tubular truss which is filled with concrete. The mid - span deflection and equivalent deflection ratio of more point support contour outside layout cable are smaller, so the economy has improved significantly. In addition, the optimization method which set equivalent deflection ratio as the objective function is simple to calculate and easy to operate. This method can be used to make optimization analysis and scheme comparison for other pre - stressed steel structure.