刚性拼接不等高布置空心板桥受力性能研究

Mechanical Properties of Unequal Height Arrangement Widening Hollow Slab Bridge with Rigid Splicing Joint

为了研究刚性拼接不等高布置空心板桥受力特性,以某座采用刚性拼接结构的新旧桥主梁不等高布置的空心板桥为对象,进行全桥足尺模型试验和非线性有限元分析,研究荷载作用下拼接结构的传力路径、受力机理和破坏模式。结果表明:刚性拼接结构能有效地传递荷载,将新板与旧板刚性连接成整体受力,且不改变新旧空心板的承载能力,拼接结构晚于空心板开裂,说明拼接结构设计合理;拼接结构与新桥边板的预埋钢筋和与旧桥边板的植筋,均不会发生破坏。拼接结构的破坏模式是弯曲产生的纵向拉应力引起拼接结构跨中截面底部混凝土开裂,继而端部拼接结构与新板处是拼接结构与空心板发生竖向剪切破坏。

In order to test the mechanical characteristics of rigid jointed hollow slab bridge with unequal height arrangement,the full-scale model test and nonlinear finite element analysis were carried out on a hollow slab bridge with a rigid splicing structure with different height arrangement of the main beams of the old and new bridges to analyze the force transmission path,force mechanism and failure mode of the splicing structure under load.The results show that the rigid splicing structure can effectively transfer the load,and the new plate and the old plate are rigidly connected into the whole force,and the bearing capacity of the old and new hollow plates is not changed.The splicing structure cracks later than the hollow plate,indicating that the splicing structure design is reasonable.Whether it is the embedded steel bars of the splicing structure and the new bridge side plate,or the planting reinforcement of the splicing structure and the old bridge side plate,no damage will occur.The failure mode of the splicing structure is that the longitudinal tensile stress generated by bending causes the concrete cracking at the bottom of the mid-span section of the splicing structure,and then the vertical shear failure occurs at the end splicing structure and the hollow plate.