地震总输入能量谱峰值估计

摘要

In order to improve the accuracy and computation efficiency of the establishment of the formulaic seismic input energy spectrum, the main factors that impact the peak value of the equivalent velocity spectrum ( VI spec-trum) and its relativity were investigated based on the input energy of 69 earthquake records with site category I ( shear wave velocity is greater than 750 m/s) in the strong earthquake database for the western region of America. The relationship between the peak value of the VI spectrum and frequency components of seismic acceleration was investigated using the Fourier transform and linear fit technique. A parameterαon the basis of the Fourier spectrum was proposed to predict peak value of the VI spectrum, and the simplified formula was established. The results show that seismic waves with similar site conditions, peak ground acceleration and duration might lead to a larger differ-ence in the peak values of the VI spectrum. The peak value of the single degree of freedom VI spectrum has a strong relationship with the concentration in low frequency and peak value of the Fourier amplitude spectrum, and espe-cially in the frequency range of 0 ~10 Hz, the correlation coefficient is at the maximum.%为了改善地震总输入能谱建立过程中峰值计算精度和计算效率，根据美国西部强震数据库中I类场地（剪切波速大于750 m/s）的69条地震记录的能量谱峰值，研究了等效速度谱（ V I谱）峰值的主要影响因素以及相关性。采用傅里叶变换和线性拟合方法，研究了VI谱峰值和地震波频率成分之间的关系。进而提出了基于傅里叶谱的VI谱峰值参数α，建立了简化的谱峰值计算公式。研究结果表明：具有相近场地条件、地震动峰值和持时的地震波可能导致较大的VI谱峰值差异；地震动傅里叶幅值谱的低频集中度、幅值谱峰值与单自由度体系的VI谱峰值有较大的关联度，其中0～10 Hz频率段的关联度最大。