基于差异谱的完全非平稳地震波与目标谱一致的调整方法

Adjusting method of fully nonstationary earthquakes compatible with target response spectrum based on difference spectrum

提出了一种使地震波拟合目标反应谱的随机方法,该地震波同时具有完全非平稳特性。首先以实际地震记录为基础,对比其反应谱与目标反应谱得到差异谱,以差异谱为目标利用谱表现方法生成与差异谱吻合的差异地震波,并用对数正态分布的概率密度函数来表征地震动的强度非平稳特性,再叠加实际地震记录和生成的差异地震波得到与目标反应谱一致的完全非平稳地震波。由此得到的地震波频率非平稳特性比较接近实际地震记录,且其反应谱与目标反应谱吻合较好,可将其用于工程结构的抗震分析中。

A stochastic method for making earthquakes compatible with target response spectrum was proposed. In the mean time, the earthquakes had fully nonstationary characteristics. First, the difference spectrum was gotten by comparing the response spectra of a recorded ground motion and the design response spectrum, then generated difference earthquakes compatible with difference spectrum through spectral representation method; second, the probability density function of lognormal distribution was adopted to express intensity nonstationary characteristics ; finally, obtained spectral compatible fully nonstationary earthquakes by adding different earthquakes to the recorded earthquake. The frequency nonstationary characteristics of simulated earthquakes were close to ground motion records, and the response spectrum of generated earthquakes fitted the target response spectrum well. Hence, the method can be used in structural seismic analysis.