某连续梁拱组合桥铅芯橡胶支座减隔震研究

Study of Using Lead Rubber Bearing for Seismic Mitigation and Isolation of a Combined Continuous Girder and Arch Bridge

连续梁拱组合桥结构受力复杂,为了保证地震作用下该组合结构桥梁的安全,需要采取减隔震措施。以某大跨度连续梁拱组合桥为背景,进行桥梁动力特性分析,选取铅芯橡胶支座作为减隔震措施;采用控制变量法,对铅芯橡胶支座的铅芯直径、支座尺寸进行组合,研究铅芯橡胶支座的减隔震效果。结果表明:铅芯橡胶支座可延长桥梁的自振周期,减轻或规避共振危害;铅芯橡胶支座的铅芯直径与支座尺寸的合理设置可大幅减小结构的内力;铅芯橡胶支座型号设置不合理时,容易增大拱顶位移,在抗震设计中需要慎重考虑铅芯橡胶支座的型号,以达到最优减隔震效果。

The mechanical property of the combined continuous girder and arch bridge is complex,and seismic mitigation and isolation measures should be taken to guarantee the safety of the combined structure during seismic events.A long-span combined continuous girder and arch bridge is cited as a case to analyze the dynamic property of the bridge of such type.Lead rubber bearings are employed as seismic isolation devices.The control variable method was used to match the diameter of the lead core with the dimension of the bearing,and the seismic isolation effect of the lead rubber bearing was studied.The results indicate that the lead rubber bearing can extend the vibration period of the bridge,mitigate or prevent resonant vibration.If the diameter of lead core and the dimension of bearing are properly fitted,the internal forces of the structure can be significantly reduced.On the contrary,if lead rubber bearings of improper specification are used,the displacement of arch crown would be intensified.In the seismic design,the selection of proper specification of lead rubber bearings should be given great concern,so as to achieve the optimal seismic mitigation and isolation effect.