远场长周期地震动反应谱拐点特征周期研究  

Characteristic periods of response spectrum for far-field long-period seismic ground motions

作　　者：周靖[1,2] 方小丹[1,3] 江毅[3] 

机构地区：[1]华南理工大学亚热带建筑科学国家重点实验室,广东广州510640 [2]华南理工大学土木与交通学院,广东广州510640 [3]华南理工大学建筑设计研究院,广东广州510640

出　　处：《建筑结构学报》2015年第6期1-12,共12页Journal of Building Structures

基　　金：华南理工大学亚热带建筑科学国家重点实验室项目(2014ZA06;2015ZB26)

摘　　要：研究远场长周期地震动反应谱两个拐点周期的统计特征以及主要因素的影响规律。考虑震中距、震级和场地类型不同,筛选长周期成分丰富的破坏性浅源强震数字化记录,通过反应谱分析,基于Newmark-Hall模型计算加速度反应谱第一下降段特征点周期和第二下降段特征点周期,分析特征周期的变化规律。结果表明:第一下降段特征点周期和第二下降段特征点周期随震中距和震级的增大而增大,场地类型对第一下降段特征点周期有显著影响,而对第二下降段特征点周期的影响不显著;震中距和震级与第一和第二下降段特征点周期的秩相关性处于中等偏弱水平,表明该两个特征点周期随震中距和震级而变化,采用单一的震中距和震级估算设计反应谱的特征点周期,并非可靠;第一和第二下降段特征点周期的线性相关性为中等偏弱水平,现有规范以第一下降段特征点周期估算第二下降段特征点周期的线性模型并不适用于长周期地震动反应谱。考虑震中距、震级和场地类型的综合影响,给出了长周期地震动反应谱第一和第二下降段特征点周期的计算模型;依据四类场地上的统计平均值,给出第一和第二下降段特征点周期建议取值,可供规范修订时参考。The effect of primary factors and the statistical characteristics of two corner periods for far-field long-period seismic response spectrum were studied. Considering the difference of epicentral distance,earthquake magnitude and site condition,the digital ground motion records with rich long-period component from destructive shallow earthquake were selected. Based on the response spectrum analysis,Newmark-Hall type models were employed to calculate the first corner period( Tg) and the second corner period( TD) of acceleration response spectrum,and the variation rule of two characteristic periods were analyzed. The results show that two characteristic periods,the Tgand TD,increase with the increase of epicentral distance and earthquake magnitude. The site conditions have significant effects on the Tg,but have minor effect on the TD. The rank correlations between the Tgand epicentral distance and earthquake magnitude,the TDand epicentral distance and earthquake magnitude,are in medium-weak level,which indicates that it is not reliable to estimate the Tg,TDthrough a single epicentral distance and earthquake magnitude,though the Tg,TDrely popularly on epicentral distance and earthquake magnitude. The linear correlation between the Tgand the TDis in medium-weak level,which indicates that the existing linear model,estimating the TDfrom the Tgin seismic design spectrum in Chinese code,is not very suitable for long-period seismic response spectrum. Considering the combined effect of epicentral distance,earthquake magnitude and site condition,the calculation model of two characteristic periods,the Tg,TD,for long-period seismic response spectrum are proposed,which can provide a reference to specification revision. According to the statistical average value for four types of sites,the characteristic period values are proposed.

关 键 词：长周期地震动 反应谱 特征周期 动力放大系数 相关性 

分 类 号：TU311.3[建筑科学—结构工程]