川滇甘陕地区反应谱阻尼折减系数研究

Study on damping coefficient of response spectrum in Sichuan, Yunnan, Gansu and Shaanxi Provinces

阻尼折减系数是建筑抗震中校正阻尼比不是5%的弹性反应谱。本文根据我国近20年来川滇甘陕地区大震时获得的强震记录的长周期特性,利用差分进化算法标定了每条强震记录并给出了不同场地上的设计谱的特征参数;最后研究了阻尼折减系数与衰减指数随震级、震中距和场地类别的影响。结果表明,建筑抗震规范中的反应谱平台值与特征周期值明显偏小;阻尼折减系数与衰减指数不随这震级、震中距与场地这三个主要地震参数的变化而变化;最后根据统计分析给出了川滇甘陕地区的阻尼折减系数与衰减指数建议公式。本文的研究将为我国抗震规范的相关修订提供了一定的参考。

The damping reduction factor is an elastic response spectrum with a damping ratio of 5%for building aseismic correction.Based on the long period characteristics of strong motion records obtained in the past 20 years in Sichuan,Yunnan and Gansu,Shaanxi Province,each strong earthquake record is calibrated by differential evolution algorithm and the characteristic parameters of design spectrum on different sites are given.Finally,the influence of damping reduction factor and attenuation index on magnitude,epicentral distance and site type are studied.The results show that the response spectrum platform value and the characteristic cycle value of the building seismic code are obviously smaller.The damping reduction coefficient and attenuation index do not change with the magnitude,epicenter distance and site.Finally,according to the statistical analysis,the damping reduction coefficient and damping index formula in Sichuan-Yunnan-Gansu-Shanxi region are proposed.The research in this paper will provide some references for the revision of seismic codes of China.