宽主梁中间索面斜拉桥空间效应分析

Spacial Effect Analysis of Wide Deck and Middle Cable-plane Cable-stayed Bridge

针对宽主梁中间索面斜拉桥受力特点,以某拟建桥梁项目为背景,建立了全桥板壳有限元模型。对主梁剪力滞、扭转效应、横向支座反力分配等空间效应进行了计算。结果表明:主梁剪力滞效应明显;扭转刚度主要由外框板件提供,且可按自由扭转公式估算;边支座在对称荷载作用下反力较小,仅在偏载作用下提供抗扭支撑。根据上述分析结果,对该类型桥梁提出了若干设计建议。

To study the structural behavior of cable-stayed bridge with wide deck and middle cable plane(s), a shell FE model is established based on a scheduled bridge project. The spacial effects including shear lag, torsion, distribution of bearing reactions, etc. are studied in detail. The results show that the shear lag effect of main beam is remarkable;the torsional stiffness is mainly provided by outer plate member thus free torsional equation is applicable for estimation; the side bearings have minor reactions under symmetric loading but provide torsional supporting under unsymmetric loading. On basis of the aforementioned fingdings, several designing suggestions are promoted for similar structures.