基于随机Fourier谱的地震动合成研究.pdf

29 2 Vo.l 29 No. 2 20094 JOURNAL OF EARTHQUAKE ENGINEER ING AND ENG INEERING V IBRATION Apr. 2009 : 000- 30 ( 2009) 02- 0007- 06 Fourier 艾晓秋, 李 杰2 ( . , 200092; 2. , 200092) : Fourier, , , , , , Fourier, FFT , : Fourier; ; ; ; : P3 5; TU3 . 3 : A Synthesis m ethod of non-stationary ground motion based on random Fourier spectra 2 A IX iaoqiu , LI Jie ( . Shangha i Institute ofD isaster Prevention and Relief, Tongj iU niversity, Shanghai 200092, China; 2. D epartment ofBuilding Eng ineering, TongjiUniversity, Shanghai 200092, China) Abs tract: Based on the random Fourier spectra corresponding to the physical random earthquakemodel and consid- ering the character of seism ic non-stationarity and the influencingmechanism, th ispaper proposes a new approach to synthesize the earthquake motion presenting non-stationarity. The basic phase angle d ifference spectrum is led in and the in itial phase angle is regarded as a random variable. The d istribution characteristics of the phase angle difference spectrum, the statistical characteristics of random ground motion and the effects on structural stochastic response are the judgm ent strategy. U tilizing the computation procedure to produce the phase angle difference spec- tra, a syntheticmethod is proposed on the basis of the random Fourier spectra. Smi u ltaneously, the fast FFT tech- n ique is applied to mi prove the synthetic accuracy. The proposed method is capable of ach ieving non-stationary earthquake motion, wh ich would provide reasonable seism ic acceleration for succeeding