结合面底部带门式钢筋的铰接空心板桥受力性能参数分析

Parameter Analysis on Mechanical Property of Hinged Hollow Slab Bridge with Gate-type Steel Bars at Bottom of Junction Surface

为研究结合面底部带门式钢筋的铰接空心板桥铰缝受力性能,以带深铰缝构造的铰接空心板桥为研究对象,总结了我国铰接空心板桥铰缝构造的演变过程,进行了一跨8 m跨径的空心板桥非线性有限元参数分析,分析了不同铰缝构造参数下空心板桥铰缝构造的开裂荷载、裂缝分布等破坏模式,讨论了现有铰缝构造的改进措施。结果表明:在结合面底部增设门式钢筋,不能明显地提高铰缝构造的开裂荷载,但可以提高铰缝构造的通缝荷载,延缓空心板与铰缝结合面竖向通缝和纵桥向通缝的形成;增大门式构造钢筋直径对结合面开裂荷载、通缝荷载和最终的裂缝分布没有明显改善;增大混凝土强度对空心板与铰缝结合面的改善作用有限;提高空心板与铰缝结合面黏结力可以提高结合面通缝荷载,并能减小裂缝分布范围;现有文献提及的3种铰缝钢筋布置形式和增大钢筋直径的方法较难从根本上改善结合面受力性能。

In order to study the mechanical performance of gate-type steel rebar, taking the hinged hollow slab bridge hinged joint in hinged with full-depth hinged object, the evolution of hinged joint structure in Chinese hinged hollow slab bridges hollow slab bridge with joint structure as study is summarized, and the parameter analysis for a hollow slab bridge with a span of 8 m is conducted by nonlinear finite element method. The failure mode of the hinged joint structure with different parameters, including crack load and distribution of cracks, is studied, and the improving countermeasures of existing hinged joint structures are also discussed. The result shows that （1） adopting gate-type steel rebar at the bottom cannot obviously improve the crack load of hinged joint, but it can delay the occurring of th of junction surface between hollow slab and hinged joint as mell as the longitudinal full-1 of junction surface e full-length cracks ength cracks ; （2） increasing the diameter of gate-type steel rebar cannot obviously improve the crack load of junction surface and the load of full-length crack and the final distribution of cracks; （3） enhancement of concrete strength cannot obviously improve the mechanical property of the junction surface; （4） the enhancement of the bound strength of the junction surface can improve the full-length crack load of the junction surface and reduce the distribution of cracks; （5） 3 layouts of the reinforcement in hinged joint and increasing diameter of steel rebar proposed inthe existing references would not fundamentally improve the mechanical property of junction surface.