摘要
采用反映地震动能量的功率谱的特征来筛选长周期地震动.定义地震动功率谱密度在0.1～0.5Hz内的面积与总面积之比大于30%的地震动为长周期地震动.与其他界定方法对比发现,用本文的方法较简单,所选的长周期地震动记录更符合长周期地震动的规律.采用本文方法分析全球不同国家和地区的约2万条地震记录,确定长周期地震动的发生概率为3%～5.5%;软弱场地的长周期地震动发生概率要大于坚硬场地;Ⅰ、Ⅱ类场地的长周期地震动发生概率为3%,而Ⅲ、Ⅳ类场地的长周期地震动发生概率为6.3%～8.3%.据此分析YJK自带天然波库中各类场地的地震记录,发现其中长周期地震动所占的比例均小于3%,特别是软弱场地的长周期地震动远低于实际发生概率.在编的建筑隔震设计标准给出的Ⅱ类场地的特殊校核波,可以较好地反映近断层效应或长周期分量等不利影响.
The characteristic of earthquake wave power spectrum was used to choose long-period ground motion.The long-period ground motion was defined as such a ground motion that the ratio of its area on ground motion power spectrum with density within the range from0.1to0.5Hz to the total spectrum area should be more than30%.Compared with other defining methods,it is found that the method presented in this article will be simple and the long-period ground motion records selected will be more consistent with the rule of long-term ground motion.Analyzing about20000earthquake records of different nations and regions in the world with such method,the defined occurrence probability of long-period ground motion is from3%to5.5%and the occurrence probability of long-period ground motion on soft ground site is more than that on hard ground site;the occurrence probability of long-period ground motion onⅠ-andⅡ-class site is3%and onⅢ-andⅣ-class site is from6.3%to8.3%.Analyzing on this basis the earthquake records of various sites in YJK’s auto-carried natural wave database,it is found that among them the proportion of long-period ground motion will be less than3%and especially,that proportion on soft ground site will be much less than the actual occurrence probability.The special verification waves for class-Ⅱsite given by the provisional code for vibro-isolation design of buildings will be able to reflect well the unfavorable influence of near-fault effect or long-period component.
作者
党育
李连峰
DANG Yu;LI Lian-feng(College of Civil Engineering,Lanzhou Univ. of Tech.,Lanzhou 730050,China)
出处
《兰州理工大学学报》
CAS
北大核心
2018年第6期112-117,共6页
Journal of Lanzhou University of Technology
基金
国家自然科学基金(51668043)
甘肃省建设厅攻关项目(JK2015-11)
甘肃省自然科学基金(148RJZA002)
关键词
长周期地震动
功率谱密度
场地类别
发生概率
长周期结构
long-period ground motion
power spectral density
site class
occurrence probability
long-period structure
