震级、震中距和场地条件对反应谱特性影响的统计分析

选取世界各地的地震记录共324组,研究了竖向与水平反应谱的比值(V/H)、反应谱峰值周期(T^p)、动力放大系数最大值(β_max)、地震影响系数最大值(α_max)和2水平向峰值周期的差值(ΔT_p)等参数,以及这些参数与场地类别、震级和震中距的关系.结果表明:1)现行规范中V/H=2/3基本符合实际情况的;2)竖向T_p略小于相应水平T_p;竖向T_p随震中距和震级增大,场地类别的影响不明显;3)α_max随震中距的增加而减小.当震中距离比较大时,场地条件对α_max值的影响不明显;4)2个水平向反应谱的特征周期存在一定差异,随震级的增大这一差异有增大的趋势.

Statistical Analysis on the Influence of Magnitude, Distance and Site Condition on Response Spectra

In this paper, 324 worldwide acceleration recordings were selected to study response spectral characteristics including vertical-to-horizontal (V/H) spectral ratio, spectral characteristics period which was corresponding to peak period (Tp), maximum dynamic amplification coefficient (βmax), the maximum spectral acceleration or maximum seismic effect coefficient (αmax) and the difference between peak periods of two horizontal components (ΔTp). This article also studied the difference of some of these parameters between vertical and horizontal recordings, as well as relationships between these parameters and site conditions, magnitude and epicentral distance. It is concluded from the statistical results that 1) the commonly used value of V/H= 2/3 in current seismic design code is reasonable and acceptable; 2) vertical Tp is usually smaller than horizontal one, and vertical Tp increases with epicentral distance and magnitude increasing, which is almost independent of site conditions; 3) αmax decreases with epicentral distance increasing. The effect of site condition on αmax is insignificant when the epicentral distance is large; 4) There is a certain difference between peak periods of the response spectrum of two horizontal components, which increases slightly with the magnitude increasing.