An improvement over Fourier transform to enhance its performance for frequency content evaluation of seismic signals

摘要

The Fourier analysis is conventional technique for approximating the frequency content of earthquake ground motions. These approaches assume that earthquake excitation is a stationary process. Time frequency analysis techniques such as wavelet transform consider an earthquake to be a non-stationary process that shows a variation in frequency content over time, but these techniques are not easy to apply and most engineers are not familiar with their sophisticated mathematics. This paper introduces a new method for investigating of frequency content of earthquake records which is more accurate than Fourier spectrum but yet easy to apply for structural design and seismological studies. The efficiency of this new approach is investigated by analyzing a variety of single and multiple degree of freedom systems against near, mid and far field earthquake components. The results demonstrate the efficiency of the proposed method for a range of systems having different natural fundamental periods. (C) 2020 Elsevier Ltd. All rights reserved.