考虑几何非线性的斜拉桥成桥索力计算

Research on Bridge-completing Cable Force of Cable-stayed Bridges Considering Geometrical Non-linearity

基于非线性有限元法,采用分步迭代算法计算斜拉桥成桥索力。首先,考虑塔柱和主梁因柔度效应对弯曲能量吸收的权的分配,按最小能量法计算出索力的初值;然后,以结构线型变化最小为目标函数进行索力迭代计算,并确定出合理成桥索力。在迭代计算中考虑垂度效应等几何非线性的影响。比较了分别采用线性和几何非线性方法计算出的某大跨径斜拉桥的成桥索力,算例表明几何非线性对成桥索力的影响较小。

A nonlinear finite dement computation procedure was presented, which considered the effects of component flexibility on the bending strain energy distribution. A reasonable adjustment value of the cable forces was obtained according to judgment criterion of the maximum and minimum bending moment of girders and cable towers. A fundamental procedure, considering the effect of geometrical nonlinearity, to determine initial cable forces in cable-stayed bridges under dead loads is presented and applied in a long-span cable-stayed bridge. The result showed that this method was reliable, convenient and effective. Based on comparative study, the geometric nonlinearity of structure has little influence on the bridge-completing cable force of cable-stayed bridges.