近场地震作用下单自由度结构强度折减系数谱  

The spectrum of strength reduction factor for SDOF systems under near-field ground motions

作　　者：张海明[1] 易伟建[1] 

机构地区：[1]湖南大学,湖南长沙410082

出　　处：《土木工程学报》2011年第10期53-59,共7页China Civil Engineering Journal

基　　金：国家自然科学基金(90815002)

摘　　要：在考虑位移延性和屈服强度比对单自由度结构强度折减系数影响的基础上,针对近场地震记录提出一个完备的强度折减系数模型。收集了近年来几次较大的近场地震动(震中距:0～30km)中的记录共计212条,并且依据场地土类别对所选记录进行分类。脉冲信号广泛存在于近场记录中,并由此产生前倾性、急冲等效应,使得近场记录具有不一样的频谱特性。已有的模型虽然也涉及到近场记录,但并没有明显突出这些特点,因而,采用已有的模型来计算结构在遭受近场记录时的强度需求,可能会导致不安全的结果。通过计算单自由度系统的强度需求和对结果进行回归分析,在满足一定位移延性以及屈服强度比下,建立适用于近场地震动记录的强度折减系数谱;并提出满足一定超越概率的模型来考虑结果的离散性。Considering the effect of displacement ductility and over-strength ratio, the spectrums of strength reduction factor for a single degree of freedom system （SDOF） under near-field ground motions are comprehensively studied. The 212 records derived from several recent near-field ground motions are categorized with respect to three types of soils. As the near-field records （NFR） contain pulse signals and inherent forward effects, so the spectrum is different from the normal records. Although, several current models also take the near-field effect into consideration, but none of them can clearly reflect these characteristics, thus when used to estimate the strength demand of the NFR, it may lead to unsafe results. Analysis of the dispersion of error is also carried out, and the probability spectrum function is also presented.

关 键 词：近场地震动 位移延性 强度折减系数 

分 类 号：P315.9[天文地球—地震学]