装配式空心板斜交桥梁横向预应力的抗裂性能研究

Cracking Resistance Performance of Precast Hollow Slab Skew Bridge under Transverse Prestressing

与普通直桥相比,装配式空心板斜交桥梁的特殊之处在于其带有一定角度的端部。在斜桥两直边施加横向预应力时,端部达不到预压的效果。针对这一问题,提出了斜交桥梁横向预应力施加的方案,并利用ABAQUS有限元软件建立装配式空心板桥梁实体模型,计算并分析了斜交桥梁横向预应力的抗裂性能。结果表明:当车辆荷载和负梯度温度场共同作用时,极易导致桥面板开裂;忽略端部影响仅在直线部位施加预应力时,其在端部区域各铰缝均未取得较好的预压效果;在斜边各1/3处施加一道横向预应力可使得绝大部分的铰缝处于受压状态,大大提高铰缝的抗裂性能。研究所得结论能为装配式空心板斜交桥梁施加横向预应力的设计提供参考和借鉴。

In comparison with ordinary straight bridge,the precast hollow slab skew bridge is special for its end with a certain angle. The preloading of the end may not be as effective as expected when the transverse prestressing is applied to the two straight edges of the skew bridge. Focusing on this issue,the scheme about applying transverse prestressing into the skew bridge is presented. Also,the solid model of precast hollow slab bridge is developed by ABAQUS finite element software and the crack resistance of skew bridge with transverse prestressing is calculated and analyzed. The results show that it is easy to result in crack when the vehicle load and negative gradient temperature field work together. Second,ignoring the influence of the end area,when the prestressing force is only applied to the straight edge,no better preloading effect is achieved in the hinge joints of the end area. Last but not the least,a transverse prestressing force is applied at each 1/3 position of the bevel edge,so that most of the hinge joints are in pressured state and the crack resistance of the joints is greatly improved. The research conclusion can provide references for the design in applying the transverse prestressing of the precast hollow slab skew bridge.