基于演变谱和正交化HHT法的类谐和长周期地震动合成

Simulation of Harmonic-like Long-period Ground Motion Based on Evolutionary Spectra and Orthogonal HHT Method

结合演变谱理论和正交化HHT法的优点,建立了一种能同时反映强度和频率非平稳特性的地震动人工合成方法.选取1999年台湾集集地震中的2条类谐和长周期地震动记录作为原始地震动进行了人工合成,并进行了局部功率谱密度分析和反应谱分析.分析结果表明,本文建立的地震动合成方法能实现对地震动频率非平稳性的模拟,合成的类谐和长周期地震动时程与原始地震动时程在能量时频分布上具有较好的一致性,且弹性反应谱及弹塑性反应谱的拟合精度较高,可供工程结构地震反应分析使用.

Combining with the advantages of evolutionary spectra theory and orthogonal HHT method,a method for the simulation of ground motions was established,which could simulate both non-stationary strength and frequency.Two harmonic-like long-period seismic records from Chi-chi Earthquake in Taiwan 1999 were selected as the original sample to simulate the long-period ground motions.The orthogonal HHT method was adopted to study the local spectral density and energy distribution of the artificial harmonic-like long-period ground motion samples.It was shown that the artificial ground motion samples obtained in the proposed method had an agreement in energy-time-frequency distribution with the original ground motions.It also has a good performance in the compatibility of elastic and elastic-plastic response spectra.The artificial harmonic-like long-period ground motions obtained in the proposed method can be used in the seismic response analysis of engineering structures.