结构-土相互作用体系的地震作用取值——基于规范-非平稳地震动模型的复模态频域法

为了求解结构-土相互作用体系的地震作用,对基于规范-非平稳地震动模型的复模态频域法进行了系统研究.首先,建立了结构-土相互作用体系的运动方程,根据上部结构的地震响应以第一阶振型为主的特点,将其按第一振型展开;然后,针对所得运动方程为非对称质量与非经典阻尼矩阵的情况,用复模态法解耦;最后,采用与抗震规范设计反应谱的地震动参数一致的Clough-Penzien-三段式非平稳地震动随机模型在频域内进行了体系的随机地震响应分析,进而得到了结构的地震作用取值.通过一个例子来说明本文方法在结构-土相互作用体系地震作用取值的应用,同时分别给出了基础固定结构基于地震动模型和规范设计反应谱的地震作用取值来进行比较.

Earthquake action calculation of structure-soil interaction system:A method in frequency domain on the basis of non-stationary seismic random model based on seismic code

In order to calculate the earthquake action of structure-soil interaction system,the complex mode frequency domain method based on seismic code-non-stationary seismic random model is studied systematically.(Firstly,the dynamic equation of structure-soil interaction system is established.According to the fact that the first mode contributes to the main part of the total motion,the structural responses are unfolded by the first mode.Aimed at the situation that the mass matrix is non-symmetric and the damping matrix is non-classical,the complex mode theory is used to decouple the equations.Then the earthquake responses and earthquake action are attained in frequency domain by adopting Clough-Penzien-three-step non-stationary seismic random model which has the same ground motion parameters as the design response spectrum of seismic code.(An example is presented to show the application of this method.And the earthquake actions of base fixed structure based on seismic random model and design response spectrum are given for comparison.