独塔单索面斜拉桥空间应力状态分析

Analysis of Spatial Stress of Cable-stayed Bridge with Single Tower and Cable Plane

现代斜拉桥多采用密索体系,属高次超静定结构,且箱 形的主梁结构空间效应明显,单纯地由平面分析很难反应桥梁 的实际受力状况。以一独塔单索面斜拉桥为背景,采用新型空 间单元———实体退化单元,考虑三向预应力效应,对其成桥状 态下的纵、横、竖向的正应力状况进行了分析。分析结果表明, 该桥在恒载下,主梁顺桥向正应力沿横向分布相当不均匀,翼 板上的顺桥向正应力明显小于主梁中间部分的正应力;塔梁相 交处主梁的横桥向拉应力偏大。空间分析结果为完善设计提 供了依据,确保了桥梁在设计上的安全。

For dense cable system, the modern cable-stayed bridge is an indeterminate structure with high degrees. And the spatial effect of the box gird is obvious. So the result of plane analysis can hardly illustrate the bridge’s real stress state. A new-type element——the degenerated solid element was used to analyze the spatial stress state of the cable-stayed bridge under permanent loads. During analyzing, the three-dimensional effect of prestress force was analyzed. The result of analysis shows that under the permanent loads, the transverse distribution of longitudinal direct stress is very asymmetry, the longitudinal stress in limb of girder is obviously smaller than that in middle part, and that the transversal stress in intercross of pylon and girder goes beyond the limit of material intension. It offers the warranty for consummating the design of Linhai Bridge, and helps to assure the structure’s safety in design.