【摘要】 利用谐小波变换对实际强震记录的时变谱进行估计,并统计分析了与抗震规范相容的3类不同场地上地震波的时变谱特征,利用均匀调制非平稳随机模型和时变修正Kanai-Tajimi非平稳随机模型模拟地震波的时变谱,把非线性函数的参数识别问题转化成求解无约束优化问题,利用拟牛顿迭代法求得最优解,得到3类不同场地上这两种模型的参数的具体取值以及参数函数集的具体表达式;研究了以谱强度因子的平方根为强度参数的双向地震动作用下隔震结构概率地震需求分析的步骤,对比了不同的地震动随机模型对隔震结构概率地震需求分析的影响,研究发现在小震作用下,地震动随机模型对隔震结构的地震响应影响不大,但在大震作用下,地震动随机模型对结构响应有较大影响,而且,对于不同场地类别,地震动随机模型对隔震结构概率地震需求分析的影响也不相同。更多还原

【Abstract】 The time variable spectrums of strong earthquake records are estimated based on the harmonic wavelet transform.The average time variable spectrums of earthquake records are simulated by uniform non-stationary stochastic model and time variable modified Kanai-Tajimi non-stationary stochastic model.The empirical formulas for the time variable spectrums of the earthquake records on three classes of sites soil are established by using nonlinear function fitting method.The step is presented to analyze probabilistic seismic demand of base isolated structures subjected to two-direction horizontal ground motions,and regard S0(S0 is spectrum intensity parameter) as the intensity measure(IM) of ground motions.The effect of nonstationary stochastic model of earthquake records on the probabilistic seismic demand analysis(PSDA) of base isolated structures is studied.It is showed that the effect is insignificant when the IM is small,but increasing the IM,the effect becomes significant.In addition,the effect is variant for different class of sites soil.更多还原