Effects of phase characteristics of simulated earthquake ground motions on the response spectra

The effects of phase characteristics of the simulated earthquake ground motions on the response spectra are examined by use of the phase difference distribution concept and the random theory. The simulated motions which have the power spectra of the recorded earthquake motions are generated for three cases of the breadth of the phase difference distributions. It is found that when the standard deviation of the phase difference distribution of the simulated motions is 0.75 of the recorded one, the response spectra of the simulated motions are almost at the same level of the recorded ones. The equivalent duration time and the equivalent r.m.s. values are also close to the recorded ones. (orig.)