一种基于非弹性收缩量的斜拉桥调索混合整数优化模型

A Mixed Integer Optimization Model Based on Inelastic Contraction for Cable Adjustment of Cable-Stayed Bridges

针对斜拉桥成桥索力调整问题,用杆单元模拟拉索,将非弹性收缩量引入拉索的自由度向量中,通过对整体结构平衡方程进行矩阵变换,建立了基于非弹性收缩量改变量的影响矩阵.利用得到的影响矩阵,在全桥调索情况下,理论上可精确达到目标索力.针对实际工程中部分调索的需求,引入0,1变量分别表示不调整、要调整某根拉索,与拉索的调索长度共同组成优化变量,建立了一个混合整数优化模型,可方便地实现部分调索优化分析.用算例演示了优化模型的有效性和可行性.

For the cable force adjustment of cable-stayed bridges,truss elements were used to simulate the cables,and the amount of inelastic contraction was introduced into the degree-of-freedom vector of the cables.Through matrix transformation of the overall structural balance equations,an influence matrix based on the amount of inelastic contraction was established.With the obtained influence matrix,in the case of the full-bridge cable adjustment,the target cable force can be accurately achieved in theory.In response to the needs of some cable adjustments in actual projects,variables 0 and 1 were introduced to indicate that no adjustment is needed,or some cable is to be adjusted.Based on the integer variables and the adjustment length of the cable,a mixed integer optimization model was established to conveniently realize partial cable adjustment and optimization analysis of the cable.The calculation example demonstrates the effectiveness and feasibility of the optimization model.