基于拉索-摩擦摆式支座的高速铁路连续梁桥减隔震研究

Research on Seismic Isolation Performance of a High⁃speed Railway Continuous Girder Bridges Using Cable Friction Pendulum Bearings

为提高高速铁路大跨度连续梁桥的抗震能力,防止梁体碰撞和落梁等震害,提出了一种新型拉索-摩擦摆式支座,研究其应用于某高速铁路(60+100+60)m预应力混凝土连续箱梁桥减隔震的效果。分析了支座拉索刚度、自由行程、布置方式和抗剪螺栓设置等设计参数对桥梁地震响应的影响。结果表明:拉索-摩擦摆式支座对高速铁路连续梁桥具有良好的减隔震效果,且可通过限制墩、梁间的相对位移从而有效防止梁体碰撞和落梁等震害;增大支座的拉索刚度,墩、梁间相对位移将减小,墩底弯矩增大,墩底剪力先减小然后趋于稳定;支座自由行程的变化对墩、梁间相对位移、固定墩的墩底弯矩和剪力的影响较小;支座布置方式对桥梁地震响应具有较大影响;考虑抗剪螺栓时,墩、梁间相对位移减小,墩底弯矩和剪力增大,抗剪螺栓对固定墩的地震响应的影响大于其他桥墩。

To improve the seismic capacity of a long-span continuous girder bridge of a high-speed railway and prevent earthquake damage such as beam collision and beam falling,a new type of cable-friction pendulum bearing is proposed,and its effect on the seismic isolation of a(60+100+60)m prestressed concrete continuous box girder bridge of a high-speed railway is studied.The influence of design parameters such as bearing cable stiffness,free running,arrangement mode,and shear bolt setting on the seismic response of the bridge is analyzed.The results show that the cable-friction pendulum bearing has a good seismic isolation effect on the continuous beam bridge of a high-speed railway and can effectively prevent seismic damage such as beam collision and beam falling by limiting the relative displacement between pier and beam.By increasing the cable stiffness of the bearing,the relative displacement between the pier and the beam will decrease,the bending moment at the bottom of the pier will increase,and the shear force at the bottom of the pier will decrease first and then tend to be stable.The change in the free running of the bearing has little effect on the relative displacement between the pier and the beam,the bending moment,and the shear force of the pier bottom of the fixed pier.The bearing arrangement has a great influence on the seismic response of the bridge.Considering the shear bolt,the relative displacement between the pier and the beam decreases,and the bending moment and shear force at the bottom of the pier increase.The influence of the shear bolt on the seismic response of the fixed pier is greater than that of other piers.