考虑天然地震特征的长周期人工地震动合成

The synthetic method of seismic waves for the long period ground motion considering the characteristics of real earthquake records

长周期地震动会对自振周期较长的工程结构造成严重影响,北京市朝阳区建有大量的高层和超高层建筑,无疑会受到未来可能的长周期地震动的考验,但由于具有长周期分量的天然地震记录缺乏,而我国抗震规范设计反应谱仅限于6s以内,因此人工模拟长周期地震动对于长周期工程结构抗震安全性具有重要意义。在三角级数合成法的基础上,提出一种具有天然地震特征的长周期人工地震动合成方法,该方法可有效地延长反应谱的周期,并且采用天然地震动的相位信息和时域包线。最后,以2011年东日本大地震中的长周期地震动记录作为原始地震动进行人工合成和对比研究。建议的人工合成地震动的方法包含了规范反应谱中的统计信息,并在一定程度上体现了天然地震的非平稳特性,对于工程结构地震反应分析具有一定意义和实用价值。

The long period ground motion is a risk for high-rise building structures. For example, such a lot of large number of high-rise buildings and super high-rise buildings in Chaoyang District of Beijing will be undoubtedly influenced by long period ground motion in the future. However, lack of the real earthquake records including the long period component has been a restriction hampering the proper design of such structures mentioned. The response spectrum used in Chinese specification design is only applicable for the structures with the period less than 6 seconds. Hence the research of the synthetic seismic wave using the artificial method is significant for the seismic safety of high- rise buildings and large-span structures. In this paper, through the introduction of the synthetic method based on the trigonometric series, the method for extending the period of response spectrum in the synthetic seismic wave is proposed. In the proposed method, the real earthquake records are adopted for the phase information and the time domain envelop. It gives simulations and comparisons by using the 2011 Great East Earthquake in Japan. This method considers the response spectrum of statistical information used in Chinese specification design and reflects the non-stationary natural seismic characteristics to a certain extent. The proposed method if of significance and application value for the research of getting long period earthquake strong ground motion through the artificial composed method.