考虑近断层地震的隔震结构增设黏滞阻尼器效果分析

Analysis of an Base-isolated Structure With Viscous Dampers to Near-fault Ground Motions

介绍了新疆近断层地震动特点及其对隔震结构的影响。在太平洋地震工程中心地震记录数据库中选取2条近断层地震记录EL-CENTRO ARRAY#6波和CHY101波,再加上按规范反应谱拟合的人工时程一起作为输入。以喀什地区某医院隔震加固为背景,对采用铅芯叠层橡胶支座的隔震体系和铅芯叠层橡胶支座与黏滞阻尼器组合的隔震体系进行动力时程对比。分析结果表明,采用铅芯叠层橡胶支座与黏滞阻尼器组合的隔震体系在人工地震动和近断层地震动作用下的隔震效果都比较明显,而仅采用铅芯叠层橡胶支座的隔震体系在近断层地震作用下无明显隔震效果,结构安全性无法保证。为保证隔震结构在各种地震动作用下的稳定性及安全性,应在隔震层中增设黏滞阻尼器,以增大结构的附加阻尼,提高隔震效果。

In the present paper, earthquakes in Xinjiang, China, and the near-fault ground motions were discussed. Base-isolated structures were introduced as well at the beginning. Two earthquake records： EL-CENTRO ARRAY #6 and CHY101 from the Pacific earthquake engineering center, and with a synthetic seismic wave, were used as the input of ground motions for seismic analyses of a hospital building in Kashi in Xinjiang province, China. Seismic responses of this building strengthened by two strategies, base isolation through using Lead-Rubber-Bearings （LRB） and LRB base-isolation along with adding viscous dampers, were compared. Through the comparative study, the isolation effect of the isolated structure only with LRB was not effective under near-fauh ground motions, while the LRB isolated structure with additional viscous dampers showed better performances due to the increasing of the damping ratio. To ensure the reliability of the isolated structure in any earthquake situation, the design of the isolated structure need to consider using additional viscous dampers to increase the damping ratio of the isolated structure.