自锚式悬索桥的主缆线形计算与误差分析

Calculation and Error Analysis of Configuration of Main Cable for Self-Anchored Suspension Bridge

介绍了基于分段悬链线法和抛物线法的自锚式悬索桥主缆线形计算的原理和步骤,考虑弯矩对加劲梁轴向刚度的影响,提出采用非线性规划方法进行迭代计算,所得计算结果与传统的影响矩阵法结果吻合.典型跨度自锚式悬索桥主缆线形的计算结果表明,抛物线法对成桥恒载状态的计算误差很小,一般可满足工程设计和施工的精度要求,但空缆吊点坐标和索鞍预偏量的计算误差很大.文中还针对不同矢跨比、跨度、边中跨比和主缆应力安全系数的自锚式悬索桥,采用抛物线法进行了主缆线形的误差分析.

This paper introduces the theory and process of the configuration calculation of main cable for self-anchored suspension bridge based on the methods of segmental catenary and parabola, put forwards a nonlinear programming method for the iterative calculation by considering the flexural effect on the axial rigidity of the beam, and verifies the accordance of the proposed method with the traditional influence matrix method. It is demonstrated by the calculated results of self-anchored suspension bridge with typical span that, by using the parabola method, the calculation error of cable configuration of a completed bridge under constant loads is small enough for the general engineering design and construction, but the errors arising from the calculation of free cable coordinate and saddle pre-displacement are both significant. An error analysis of the configuration of the main cable for a self-anchored suspension bridge is finally performed by means of parabola method with respect to the rise-to-span ratio, the main span, the side span-to-middle span ratio and the stress safety coefficient of main cable.