Simulation Of Non-Stationary Ground Motion Processes Compatible With Prescribed Response Spectrum

Simulation methods for generating earthquake with target spectra compatible with prescribed response spectra are investigated in this paper. To get more realistic results, a new method is proposed based on Hilbert-Huang transform(HHT).Compared to present research situation, the research work in this paper supplies a comparatively accurate method for the simulation of non-stationary ground motion processes. Firstly, after a quick review of the research on non-stational ground motion with equivalent Stochastic characteristics, the weaknesses of traditional methods which are able to consider the non-stationarity of ground motion amplitudes only are illustrated. This new simulation method is introduced in this paper next. According to it,those simulated sample processes reflect the earthquake ground Motion's non-stationary both in amplitude and frequency content related closely to the time-dependent object Power spectra which is one theory basis for the research work herein. The HHT method is also summarized briefly in this paper and compared with Fourier transform and wavelet analysis. The HHT method is developed through integrating empirical mode decomposition (EMD) and classical Hilbert transform. The Hilbert spectra resulted from HHT can provide more significant description of time-varying frequency composition and thus represent the non-stationarity of earthquake ground motion more accurately. On basis of the theory discussed above, an effective method for simulation of non-stationary ground motion processes is illustrated in more detail subsequently. This innovative method, based on the technique of amplitudes correction, integrating with the HHT method and introducing the Hilbert spectra, enables it possible to maintain the non-stationarity both in amplitudes and frequency content of the original earthquake record. Finally, with El Centro strong ground motion recording being the original recording and response spectra of first kind ground the target spectra, the accuracy of this proposed method is verified.The conclution reached is that it is able to represent the non-stationarity of earthquake ground motion more veritably and thus...