全非平稳地震动过程的概率模型及反应谱拟合

在强度调制函数基础上,发展了一类全非平稳地震动过程的时-频调制函数。结合平稳地震动过程的功率谱密度函数,建立了全非平稳地震动过程的演变功率谱模型,并根据建筑抗震设计规范确定了模型参数的取值。应用非平稳过程模拟的谱表示-随机函数方法,生成具有完备概率的非平稳地震动加速度过程的代表性时程集合,进而计算代表性时程的平均反应谱。为保证计算平均反应谱与建筑抗震设计规范反应谱的一致性,建议了反应谱容许误差的双重控制准则,即平均相对误差和最大相对误差。研究表明,通过对演变功率谱的3次迭代修正,即可实现计算平均反应谱与规范反应谱拟合的目的,为应用结构随机动力学进行实际工程结构抗震设计提供了依据。

Probability model of fully non-stationary ground motion with the target response spectrum compatible

Based on the intensity modulation function,a class of extended time-frequency modulation function for non-stationary ground motion was developed. In conjunction with the power spectral density function of stationary earthquake processes,an evolutionary power spectra model of fully non-stationary ground motion was established. The values of the model parameters were determined according to the Chinese code for seismic design of buildings. Applying the simulation method of hybrid spectral representation and random function for non-stationary stochastic processes,a complete set of representative seismic time-histories with assigned probabilities was obtained,and the average response spectrum of representative seismic time-histories was determined accordingly. In order to ensure the calculated average response spectrum to be in agreement with the design response spectrum,the average relative error and the maximum relative error were suggested to control the tolerance between the two response spectrums. The agreement was realized through three times iterative corrections for the evolutionary power spectra. The study provides a basis for the application of stochastic dynamics of structures in engineering practices.