斜拉人行桥拉索承载力非线性有限元分析

Nonlinear Analysis on Force-bearing Capacity of Stayed Cables of a Large Scale Footbridge

采用多节点索单元研究了斜拉人行桥拉索承载力问题。首先基于多节点索单元建立了坐标系及非线性应变表达式,形成了索单元的应力应变关系。进一步建立了索单元的弹性刚度矩阵、初位移刚度矩阵和初应力刚度矩阵的表达式,建立了斜拉索承载力的非线性迭代方法,利用Newton-Raphson迭代实现计算求解。以某大跨度斜拉人行桥为工程背景,系统研究了其斜拉索的承载力问题。结果表明,弹性模量和自重荷载强度对斜拉索的承载力性能均有一定程度的影响。弹性模量的增加将导致拉索的刚度增加和跨中的竖向位移减小,而自重荷载的增加则导致跨中位移的增加。对比分析结果可知,对拉索承载力影响较大的参数是自重荷载的强度,相对而言弹性模量的影响较小。

The force bearing capacity of stayed cables of a large scale footbridge is investigated in this study by using multinode cable elements. The coordinate system and nonlinear strain expression are firstly established to construct the stress-strain relationship. Then,the elastic stiffness matrix,initial displacement stiffness matrix and initial stress stiffness matrix are developed and the nonlinear solving approach is constructed based on the Newton-Raphson iteration algorithm. A large scale cable-stayed footbridge is taken as an example to examine the force-bearing capacity of stayed cables. The made observations indicate that Young＇s modulus and self-weight have some effects on the cable performance. The increase of Young＇s modulus may induce the strength of the cables and the displacement decrease in the main span. However,the increase of self-weight may induce the displacement increase in the main span of cables. To compare the effects of the two physical parameters,one can find that the selfweight has relatively large influence on the force-bearing capacity of the cables than the Young＇s modulus.