曲线箱梁桥空间预应力效应分析

Effect of spatial prestressing for curved box girder bridges

曲线箱形梁桥是空间复杂受力的结构体系,预应力效应一方面能提高构件的承载能力,另一方面也可能对结构带来一些不利的影响。采用三维实体单元和杆单元相结合的空间组合有限元方法,对一座两跨曲线预应力混凝土箱形连续梁桥进行空间受力分析。针对曲线箱形梁的力学特点,对空间曲线钢束摩阻损失的计算方法进行分析。采用组合有限元法和简化方法分析预应力径向力对箱梁腹板的作用效应,比较两者的计算结果差异。采用两种计算模型,分析了预应力对支座受力的影响,对径向支座间距设置和改善支座受力的方法进行了研究。根据预应力效应的分析结果,得到了一些有益的结论,为进一步完善曲线预应力混凝土箱梁桥的设计提供了依据。

Curved box girder bridge is a complicated spatial structural system. The effect of prestressing may improve the bearing capacity of the members, but may also adversely affect the structure. Using a spatial composite finite element method, combining three-dimensional solid element and bar element, the mechanical analysis of a two-span curved PC continuous box girder bridge is conducted. According to the mechanical characteristics of the bridge, the calculation method for prestress friction loss of the spatial curved prestressed wires is studied. The impact of prestressing radial force on the web plate is analyzed, and the composite finite element method and a simplified method are compared. Two computational models are established to study the influence of prestressing on the bearings, the spatial arrangement between the radial bearings and the approach to promote the performance of the bearings.