近断层区桥梁组合使用板式橡胶支座和黏滞阻尼器方法探讨

Study on Application of Viscous Dampers Installed in Continuous Bridges on Elastomeric Pad Bearings in Near-Fault Regions

选择具有脉冲性质的近断层区地震动记录和无脉冲地震动记录作为地震输入,考察了近场脉冲型地震动对我国常见的板式橡胶支座类型桥梁地震反应的影响。针对国内外抗震规范及学者提出的橡胶支座与黏滞阻尼器组合使用方法,研究了近场脉冲型地震动作用下板式橡胶支座桥梁组合使用黏滞阻尼器的减震效果,探讨了橡胶支座与黏滞阻尼器组合使用时可能存在的问题。结果表明,近场脉冲型地震动对桥梁结构地震反应影响明显,显著增大了板式橡胶支座桥梁的墩柱地震力、梁体地震位移及梁体残余位移;组合使用黏滞阻尼器方法虽能一定程度上控制梁体地震位移及残余位移,但同时以增大墩柱地震反应为代价;近场脉冲型地震动作用下,板式橡胶支座桥梁支座滑动后整桥体系缺乏自恢复力、震后存在梁体残余位移,组合使用黏滞阻尼器无法根本解决,可在支座与墩、梁间设置连接措施加以改善。

Based on ground motion records with or without pulse effect recorded in near or far-fault regions, the influence of near-fauh pulse-like ground motions on seismic responses of continuous bridges on elastomeric pad bearings which are commonly used in China are analyzed in this paper. As recommended by some scholars and guide specifications for seismic design at home and abroad, the damping effect of the method in which vis- cous dampers are used in combination with elastomeric pad bearings in continuous bridges is studied, and the possible defect of the method is discussed. The results show that the influence of the near-fault pulse-like ground motions on bridge structures is apparent, which significantly increases the seismic forces of piers and girder maximum and residual displacement. Adopting viscous dampers in combination in bridges on elastomeric pad bearings can reduce maximum and residual displacement of the girder to some certain extent, while the seismic forces of piers will increase. And the problem of bridges on elastomeric pad bearings, in which large girder residual displacement exists after earthquakes due to a lack of restoring force in superstructure after bearing sliding under near-fauh pulse-like ground motions, can not be fundamentally solved. That may be settled by installing connecting device between elastomeric pad bearings and piers or girder.