改进力密度法在悬索桥主缆找形中的应用

Modified Force Density Method for Form-Finding of Main Cable of Suspension Bridges

摘要:

针对悬索桥成桥和空缆两种状态的主缆找形问题，提出了改进力密度法。该方法结合无应力长度的概念，假设初始缆形为直线段。通过力密度法建立结构平衡方程求解节点坐标，反复迭代，求出控制条件下的目标缆形。以新建成的徐州京杭大运河地锚式悬索桥为依托，利用Matlab编程求解主缆缆形，并将数值计算结果与坐标实测值进行比较，结果表明该方法收敛稳定，计算效率高，并具有较高的精度。同时，通过算例验证了论文提出的方法对于空间缆形自锚式悬索桥同样适用。

Abstract:

Aimed at the problem of main cable form-finding of suspension bridges in the finished dead load state and the unloaded state， a modified force density method is proposed. This method combines the concept of unstressed length， assuming the initial cable shape is straight line segment. A structural balance equation is established to find the target cable shape under limited conditions by iterations， which is based on the force density method. The proposed method was used to calculate the cable shape of the Beijing-Hangzhou Grand Canal Suspension Bridge by Matlab. The comparison of the numerical calculation results and measured values of the coordinates shows that the proposed method has a stable convergence， high computational efficiency and high accuracy. The proposed method was verified to be suitable for self-anchored suspension bridges with three-dimensionally cables through the calculation example.