小剪跨比钢管混凝土组合桥墩抗震性能试验研究

通过6个剪跨比λ=1.5桥墩试件的拟静力加载试验，研究了内置核心钢管对小剪跨比钢筋混凝土桥墩抗震性能的改善作用，并讨论了轴压比、纵筋率、配箍率和钢管率对小剪跨比钢管混凝土组合桥墩抗剪强度、变形能力、强度衰减以及累积耗能的影响.试验结果表明：钢筋混凝土桥墩试件在水平往复作用下呈脆性的剪切斜拉破坏，组合桥墩试件则表现为具有一定延性的剪切斜压破坏；内置核心钢管可延缓墩身的损伤发展并改变其脆性失效模式，从而使组合桥墩试件的抗震性能较普通桥墩对比试件有着明显提升；随着钢管率和配箍率的增加，组合桥墩试件的抗剪强度、位移延性和耗能能力均得到改善；组合桥墩试件的抗剪强度随轴压比和纵筋率的增加而提高，但位移延性和耗能能力变差.试验结果可为小剪跨比组合桥墩的理论研究和工程应用提供试验基础.
Six bridge column specimens with shear span ratio of λ=1.5 were tested under combined constant axial load and lateral reverse loads. The effectiveness of built-in steel tube in enhancing the seismic behavior of RC stub bridge column was evaluated. Besides, the influence of axial load ratio, longitudinal rebar ratio, stirrup ratio, and steel tube ratio on the shear strength, deformation capacity, strength attenuation, and energy dissipation of STRC stub bridge columns was also discussed. Test results indicate that the failure patterns of RC and STRC stub bridge columns were shear diagonal-tension failure and ductile shear diagonal-compression failure, respectively. The existence of core steel tube alleviated the damage of RC stub bridge column and changed the brittle failure into a ductile fashion, which significantly enhanced the seismic behavior of STRC stub bridge column specimen over the RC counterpart. The shear strength, ductility and energy dissipation of STRC stub bridge column were improved with the increase of steel tube ratio or stirrup ratio. With the increase of the longitudinal rebar ratio or axial load ratio, the shear strength of STRC stub bridge column gained a noticeable increment, while the ductility and energy dissipation tended to deteriorate. Test results in this paper could provide reference for theoretical research and practical application of STRC stub bridge columns.