摘要
本文旨在分析脉冲型地震动中不同频率的地震动分量对于原始地震动幅值及其非弹性反应谱的影响.首先以近期12次大地震的53条典型脉冲型地震动为数据基础,基于多尺度分解方法获取脉冲型地震动中的高频分量和低频分量.为与传统方法对比,本文获取了能够表征地震动脉冲特性的卓越分量及滤除卓越分量的剩余分量.然后对比分析原始地震动和4种地震动分量的幅值特征和非弹性反应谱的特性,以讨论地震动分量对原始地震动幅值参数及其非弹性反应谱的影响.最后结合简谐地震动模型和地震动分量的性质,讨论脉冲型地震动非弹性反应谱诸多特征的产生原因.分析发现,低频分量不仅是控制脉冲型地震动速度和位移幅值的主要因素,其对原始地震动的加速度幅值也具有不可忽略的影响.低频分量也是导致脉冲型地震动非弹性位移比谱偏大以及强度折减系数谱偏小的直接原因,从而造成结构在脉冲型地震动作用下需要具有更大的非弹性位移以及更高的强度需求.
The inelastic displacement ratio spectra of pulse-type ground motions always have higher spectral values than ordinary ground motions.And the inelastic strength reduction factor spectra of this type motions are usually less than those of ordinary ground motions.That will result in higher displacement and strength demands for building structure when the structure is subjected to pulse-type ground motions.This article attempts to investigate the influence of different frequency components on the amplitude parameters and inelastic response spectral characterizations of pulse-type ground motions.In total,53pulse-type ground motions selected from 12 large earthquakes are utilized in this study.And multi-scale decomposed method is adopted to obtain different frequency ground motion components.The frequency content of the ground motion component obtained by the multi-scale decomposed method is very simple.So this type of ground motion component is termed as simple component.To investigate the influence of the ground motion components in different frequency ranges on the original ground motion（OGM）,high frequency component（HFC）and low frequency component（LFC）are defined.The HFC is the linear summation of the simple components with the period less than 1s,and the LFC is the linear summation of the simple components with the period no less than 1s.To compare with the results obtained by traditional methods,the predominant component（PC）which can be used as the representation of the dominant velocity pulse and the residual component（RC）which is obtained by removing the PC from original ground motion are analyzed. To explore the reasons for the special characterizations of the inelastic response spectra for pulse-type ground motions,a harmonic ground motion model is used in this study.This article first studies the relationship of the three kinds of amplitude（PGA,PGV and PGD）between original ground motion and the four kinds of ground motion components（LFC,HFC,PC,and RC）.Analyses show that the velocity amplitude of PC is less than that of LFC and RC,but the correlation coefficient of the PGV between PC and OGM is more significant.There is a weak relationship of the displacement amplitude between HFC and OGM.Both of the correlation coefficients for PGV and PGD between LFC and OGM are larger than 0.9,but the correlation coefficient of PGA between LFC and OGM is still very large.And then the comparison of the inelastic response spectra between original ground motions and four kinds of ground motion components（HFC,LFC,PC,and RC）is performed.Analyses indicate that the inelastic displacement ratio spectra（IDRS）of HFC and RC are less than those of OGM which is consistent with previous analysis results.The IDRS of LFC and RC is significantly larger than that of OGM.The inelastic strength reduction-factor spectra（ISRS）of PC and LFC are less than those of OGM,and the difference between PC and LFC is not significant.The ISRS of RC and HFC is larger than that of OGM in short-period regions,and the ISRS of LFC is more approximate to that of OGM in long-period regions.The results show that low-frequency component is the major factor that influences the velocity and displacement amplitude of pulse-type ground motion. And it can also cause considerable influence on the acceleration amplitude of original ground motion.Besides,lowfrequency component is the immediate causes of the larger inelastic displacement ratio and the smaller inelastic strength reduction factor for pulse-type ground motions.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第8期2962-2974,共13页
Chinese Journal of Geophysics
基金
国家自然科学基金重大研究计划集成项目(91215301)
国家自然科学基金重点项目(51238012)和面上项目(51178152)
山东省科技发展计划(2014GSF122001)
山东省蓝色经济区工程建设与安全协同创新中心资助
关键词
脉冲型地震动
多尺度分解方法
等延性反应谱
非弹性位移比
强度折减系数
Pulse-type ground motion
Multi-scale decomposed method
Constant ductility response spectra
Inelastic displacement ratio
Strength reduction factor
作者简介
赵国臣，男，1990年生，博士研究生，主要从事防灾减灾工程研究．E-mail：zgc011@126．com
通讯作者 徐龙军，男，1976年生，博士，教授，博导，主要从事防灾减灾工程研究．E-mail：xulongjun80@163．com
