site condition

• According to the structural dynamic behaviors under different site conditions and seismic waves with different platforms , the relationships between the structural response and site predominant period , as well as platform of seismic wave were built up , by which the most unfavorable earthquake excitations of single - layer spherical shell were obtained
  通过对场地卓越周期及地震波平台段持时的研究，建立结构动力响应与场地卓越周期及地震波平台段持时之间的关系，明确了何种条件下的荷载为结构最不利外荷载。
• All records are classified into three site conditions . for the two components of a record , two energy equivalent spectra are calculated , and the geometric mean of the two spectra are adopted to analysis by two - stage regression method using an attenuation model . then the attenuation law is attained
  对每一条记录，取了两个分量所计算的能量谱的几何平均值，选择了衰减模型，利用两步回归法，对这些能量等效速度谱做了统计拟合分析，得出了地震动四种能量反应谱随震级、距离等参数的衰减规律。
• Using the methods of summation by giving a mark and main component analysis , the result indicates that the methods of main component analysis is identical better with reality than the methods of summation by giving a mark , the differentiation trend of types of site conditions of cornus officinalis chiefly receives the accuse in soil fertility factor and the general configuration of the earth ' s surface factor
  结果表明：主分量分析法与打分求和法相比，以主分量分析法划分的类型与实际吻合更好；山茱萸立地条件类型的分化趋势主要受控于土壤肥力因子和地貌因子。
• In addition , effects of several factors such as local site conditions , focal mechanism , epicentral distance and seismic magnitude on these parameters are discussed , and several significative results and conclusions are obtained . in all records there are about 1 / 3 vertical ground motion ’ s peak acceleration bigger than 2 / 3 of the corresponding horizontal one , so the action of vertical ground motion should not to be underestimated . vertical design response spectrum equals that the horizontal design response spectra times 65 % is probably unsafe when period is short , and suggest adopting different coefficients when at different periods
  本文基于对大量欧洲强震记录的研究,分析了地震动竖向与水平向分量在峰值加速度、反应谱值、频谱周期等参数方面的差异,以及这些参数与场地、震源机制、震级和震中距的关系,得到了以下有意义的结果和结论:在本文分析的地震记录中大约1 / 3的记录加速度峰值比大于2 / 3 ,竖向地震动分量的作用不可低估;在短周期,竖向地震动影响系数的最大值仅取为水平向地震动影响系数最大值的65 %是偏于不安全的,可以考虑按周期分段采用不同的折减系数;我国现行抗震规范中设计反应谱特征周期的取值偏低,可能是偏于不安全的;竖向与水平向地震动分量卓越周期的比值在0 . 7 - 0 . 9之间,竖向设计反应谱的特征周期应有单独规定。