【摘要】 根据前人对地震动主轴的研究,近似定义了某一点的地震动主轴方向:第一、二主轴方向为该点至震中的径向和切向,第三主轴方向为竖直方向;通过分析集集地震记录在所定义主轴上的相关情况初步验证了主轴方向近似的合理性。在一维地震动合成公式的基础上,根据地震动主轴功率谱密度函数合成三维空间非平稳的地震动时程,回避了地震动各分量相干性难以确定的难题,并考虑了空间各点地震动自谱强度的变化,以便更好地适用于大尺度结构的多点输入分析。更多还原

【Abstract】 Based on the study of principal axes of earthquakes,approximate direction of principal axes is proposed,whose rationality was verified by Chi-Chi earthquake. To simplify the calculation and analysis: the major and intermediate principal axes point in the direction along and perpendicular to the connection between the recording station and the epicenter; the minor principal axis is vertical. According to the power spectral density functions along principal axes,the simulation of spatially correlated earthquake ground motion of three-dimension are carried out on the basis of the simulation of one-dimensional earthquake to avoid considering the seismic spatial coherence that is hard to estimate. In addition,the variation of amplitude of white-noise bedrock acceleration is taken into consideration,which is suitable for the simulation of multi-point ground motions of large scale structures.更多还原