悬索桥索塔稳定性全过程分析

Research on Stability of Pylon of Suspension Bridge

作为悬索桥受力体系中的重要承重构件,索塔的受力性能也成为悬索桥设计中至关重要的一环.为了分析悬索桥主塔的稳定性问题,采用有限元法,建立了索塔及全桥的有限元模型,并对裸塔和成桥阶段索塔工况下的两类稳定性进行对比分析,主要考虑非线性因素、初始缺陷、索塔刚度、约束条件和静风荷载五种因素进行分析计算.研究结果表明,初始缺陷、索塔刚度及静风荷载对索塔的稳定性影响较小;约束条件对索塔稳定性的影响十分明显,塔顶主缆的弹性约束刚度越大,稳定安全系数的变幅越小,最后趋于一个定值.

As the core component for load-bearing, the mechanical property of the pylon therefore becomes one of the most crucial factors in bridge design. In order to analyze the stability of main towers of the suspension bridges, finite element model of a suspension bridge including its tower and the whole bridge has been created by the software ANSYS to do some contrastive analysis of stability under 2 cases （free standing tower and tower on finished stage）. 5 major stability-influential factors： nonlinear factors, initial imperfections, constraint conditions, pylon rigidity and static wind load are chosen for the simulation. The researching results indicate that the influences of initial imperfections, pylon rigidity and static wind load to stability of the towers are relatively small while the influence of constraint conditions is quite significant. Furthermore, the varying amplitude of the stability-safety factor keeps decreasing with increase of the elastic restrained stiffness of main cables on the tower top and finally becomes stable at a constant value.