基于时-频包线函数的多点地震动合成

Simulation of multi-supported earthquake ground motion based on frequency-dependent amplitude envelope function

地震动频率非平稳特性对结构响应有重要影响。本文通过引入随频率变化的包线函数,近似模拟地震动频率的非平稳特性,建立了能够考虑地震动频率非平稳特性的空间相关多点地震动的合成方法。实例分析表明,本文给出的拟合方法能够较好地反映地震动频率的非平稳特性,强调地震动时程在下降段的低频成分。由于在本文给出的模拟方法中,可以采用不同的时-频分析工具构建随频率变化的强度包线函数,所以非常适合于工程应用。

There is important effect of non-stationarity of frequency in earthquake ground motion on structural responses. Therefore,the non-stationarity of earthquake ground motion is simulated by introducing the frequency-dependent amplitude envelope function. Based on this,a simulation method for spatial correlated multi-supported ground motion is developed,which can consider the non-statioarity of frequency in ground motion. An example is used to analyze the effect of amplitude envelope function,and the results show that simulation method derived in this paper can consider the non-stationarity of frequency,and emphasizes the effect of low-frequency component in later seismic actions. In addition,because frequency-dependent amplitude envelope function can be established by many time-frequency analysis tools,the simulation formula developed in this paper is suitable for application in engineering.