基线漂移对长周期反应谱的影响

The effect of baseline offset to response spectra in long period

采用Hilbert-Huang变换,对数字强震仪记录进行了分析,得到了几个典型记录的最低频固有模态函数(IMF),比较了常规处理记录和去除最低频IMF的记录加速度反应谱的差别,这种差别很小。据此得出了记录基线漂移对长周期反应谱的影响很有限的结论,指出数字化强地震动记录在长周期段是可靠的,设计反应谱可向长周期扩展。

Hilbert - Huang Transform is adopted to deal with strong motion records, the lowest frequency inherent mode function（IMF） of some representative records are drawn out. The difference is very small between general records and those without the lowest frequency IMF. The result are drawn that the effect of baseline setoff is finite to response spectra in long period, the digital strong motion records are credible in long period, the design response spectra can be extended to longer period.