近断层脉冲地震动对基础隔震结构放大效应的量化分析

为量化分析近断层脉冲地震动对基础隔震结构的地震放大效应，建立多层和高层两个基础隔震结构模型，根据隔震结构基本周期，采用基于能量的脉冲量化识别方法，得到40条脉冲地震动，并剔除其中的主脉冲，产生40条非脉冲地震动。将这80条地震动分别输入两个隔震结构，量化分析脉冲地震动对其层间位移角、楼层剪力、楼层加速度和隔震层位移的放大效应。结果表明：脉冲地震动作用下基础隔震结构的反应明显大于非脉冲地震动，脉冲地震动对隔震层位移放大系数最大，而楼层加速度放大系数对脉冲地震动比较敏感，呈现出波浪形的变化特征。两个隔震结构所得到的隔震层位移的放大系数平均值约为2.0，层间位移角、楼层剪力、楼层加速度的放大系数平均值约为1.5。

Quantitative study on amplification effect of base-isolated structuressubjected to near-fault pulse-like ground motions

Two structural models representative of low- and high-rise base-isolated buildings were constructed and used to quantify the amplification effects resulting from near-fault pulse-like ground motions. Forty ground motions with typical pulses are selected with respect to the fundamental periods of the two structural models. And then the primary pulses inherent in the pulse-like ground motions are subtracted to secure the non-pulse-like ground motions. With eighty ground motions as the inputs for non-linear dynamic analysis, the inter-story drift ratio, story shear, story acceleration and the displacement in the isolated story are quantitatively analyzed. It is concluded that the seismic responses from the pulse motions are significantly larger than those from non-pulse ones. The amplification coefficients for the displacements in base-isolated story are the largest, while the coefficients for the story acceleration are more sensitive to the characteristics of the pulses. The mean value of the amplification coefficient for the displacement in the isolated story is close to 2.0. And the mean value of the amplification coefficients for the inter-story drift ratio, story shear and the story acceleration is around 1.5.