本文採用將強度包絡曲線視為地表震動之相位差的機率密度函數之方法，產生符合設計譜之人工地震，因此藉著改變強度包絡曲線之參數值和產生相對應的做為相位差之亂數的種數數值，可以求得符合同一設計譜之許多具不同相位的人工地震。 本研究利用五層樓之剪力構造探討具不同相位的人工地震對樓板反應譜的影響，而所考慮的參數為種數、強度包絡曲線所圍成面積的切割數目、強度包絡曲線之上升與下降時間。由研究結果得知，改變此四個參數所產生具不同相位角之人工地震，對樓板反應譜和人工地震自身之FFT內涵有相當的影響，故僅取單一符合設計譜之人工地震作為地震力輸入，以評估結構的耐震性並不具有代表性。 In this study the spectrum-compatible artificial earthquakes are generated by treating the envelope function of earthquakes as the probability density function of phase differences. By varying the values of the parameter describing the envelope function and seed number for generating random number representing phase differences, a number of different spectrum-compatible earthquakes with different phase characteristics can be obtained. A five-story shear type building is then adopted to investigate the phase characteristics on the floor response spectra, and the parameters considered are the seed number and the number of discrete interval, rise time and decay time of envelope function. It is found that the phase characteristics has significant effect on the floor response spectra and the FFT content of the earthquake itself. Therefore, using only one spectrum-compatible artificial earthquake as the input for seismic resistant analysis may not be adequate.
