铁路隔震连续梁桥地震碰撞响应研究

在地震作用下隔震桥梁的梁体位移比非隔震桥梁明显增加,使得相邻梁发生碰撞的概率增大。以1联3跨铁路隔震连续梁桥为例,选用3条人工地震波,采用非线性时程分析方法进行该桥的碰撞响应分析,研究梁间伸缩缝宽度和隔震支座刚度对梁间碰撞响应的影响。结果表明:随着伸缩缝宽度的增大和隔震支座刚度的增大,相邻梁碰撞的发生次数和碰撞力均有明显减小;地震作用下隔震固定墩墩底最大弯矩和最大剪力均随着隔震支座刚度的增加而增加。因此,在进行隔震桥梁设计时,应综合考虑隔震支座的隔震效果和碰撞响应,从而得到既经济又安全的隔震桥梁设计参数。

Study on the Seismic Pounding Responses of Seismically Isolated Railway Continuous Beam Bridge

The beam displacement of seismically isolated bridge is much larger than that of non-isolated bridge under earthquakes,which increases the possibility of pounding between adjacent beams.The pounding responses of a 3-span seismically isolated railway continuous beam bridge were calculated and analyzed subjected to three artificial earthquake waves using nonlinear time history method.The influences of expansion joint widths between beams and the stiffness of isolation bearings on pounding responses were studied.The results show that both the pounding times and pounding forces are reduced obviously with the increase of expansion joint widths and the stiffness of isolation bearings.The peak bending moment and peak shear force at the bottom of the seismic isolation fixed pier are enhanced with the increase of the stiffness of isolation bearings.Thus,in the design of seismically isolated bridge,the isolation efficiency and pounding responses between beams should be considered comprehensively to achieve the safe and economic design parameters for seismically isolated bridges.