Power Spectrum Model Of Ground Motion Based On Finite Fault And Its Appliction

The study shows that the non-stationary seismic characteristics of the ground motion can not be neglected in the seismic response of the nonlinear structure.The modeling of non steady and steady vibration is a hot spot in earthquake research.Based on this paper,a seismic evolution power spectrum model with clear physical meaning is proposed and applied to the random seismic response analysis of the latticed shell structure.The research includes the following:Firstly,considering the fracture process of the earthquake,a new power spectrum model for the parameterized evolution of non steady vibration is established.Among them,the faulting along the diagonal rectangular fault propagation;time domain seismic wave propagation medium is homogeneous and isotropic,envelope motion formula;the frequency domain,using seismic spectrum model parameter model and the transfer function of media model to describe the spectral characteristics of ground motion.The expression of the power spectrum model of the non flat ground motion is determined by combining the ground motion envelope and the spectrum model.The parameters of the model have a clear physical meaning,which can be identified by seismic source geometric analysis and ground motion spectrum recognition.The artificial ground motion samples can be easily obtained by using the spectral representation method.Later,in order to verify the validity of the model for the 1994 north ridge earthquake measured ground motions are modeled,the evolution of power spectrum of measured north ridge earthquake ground motion model,simulation of ground motion samples and measured time history comparison showed that the evolution of power spectrum proposed this research model can accurately reflect the real vibration non-stationary.Finally,by using the characteristic model of the random seismic response analysis of space truss structure.The finite element model of a three-dimensional network frame structure is established by using SAP2000 software and Its characteristics are analyzed100 seismic time history samples which are obtained by using the spectral representation method and The corresponding structural responses of the 100 seismic samples are calculated.By statistical analysis of the response,the random seismic response of the gridstructure is obtained in the mean and variance sense.This study is an attempt and discussion of the time history method,and also provides a basis and reference for seismic response analysis and seismic design of civil engineering structures.