产生时程分析用的高质量地面运动时程的新方法

研究了调整地震加速度时程历史记录以逼近目标反应谱的方法,得到了满足工程结构非弹性分析所需的高质量的地震地面运动加速度时程.一方面,利用短时傅立叶变换对实际地震记录进行时频分析,把修改的傅立叶谱逆变换到时间域可以得到新的地震加速度时程.另一方面,通过叠加单位脉冲响应函数,直接调整实际地震记录,也可以使其反应谱逼近规范的目标反应谱.结合整体调整法,上述两种方法都可以快速地由实际地震地面运动时程历史记录形成与目标反应谱高度一致的新加速度时程,并且保持原地震地面运动时程历史记录的非平稳性和持续时间.还开发了相应的程序ACOTAS.作为对比,又用传统的频域法进行了地震地面加速度时程历史的调整.相比之下,两种方法产生的时程历史的质量好、效率高.

NEW METHODS FOR GENERATING HIGH QUALITY ACCELERATION TIME HISTORIES

To generate high quality acceleration time histories for nonlinear seismic response analysis, two methods for adjusting accelerograms to be compatible with target response spectra are investigated. Short-time Fourier transform is used for time-frequency analysis of recorded accelerograms, and the inverse transform on adjusted Fourier spectra yields the adjusted time histories; the recorded accelerograms can also be adjusted by adding unit impulse response functions to be compatible with target response spectra. The two methods generate response-spectrum-compatible acceleration time histories quickly while maintaining the non-stationarity and durations of the original recorded accelerograms. Implementation of the proposed methods is discussed and a computer program ACOTAS was developed. Results of an example show that the methods give better acceleration time histories quickly.