Wizard Waveform Analysis Of Strong Motion Records

For nearly ten years,the domestic and foreign strong motion network construction has been on an unprecedented scale,and the occurrence of destructive earthquakes has enriched strong motion records,which has accumulated a lot of valuable information for the further study of earthquake engineering and engineering seismology.However,with high-quality strong motion records captured,some abnormal strong motion data also appeared.So,we have to identify and process the strong motion records with wizard waveform so as to prevent the adverse impact on the related research.Strong motion records with singular asymmetric waveforms and spike phenomenon have been summarized in the paper,its causes has been analyzed,and recognition and processing methods have been given.In the meanwhile,we have studied the effect of the time history,response spectrum and Fourier amplitude spectrum before and after correction.The details of some understanding and achievement of main research are as follows:1.Generally,the area average method,modified moving average method and centroid method can be applied to identify acceleration records with the characteristics of asymmetric waveform.Then OPENSEES is used to study strong motion records from the station coded by IWTH25 after establishing the site soil layer model with physical parameters,which has explained the mechanism of asymmetric waveform to a certain extent in accordance with actual records.At the same time,the asymmetric waveform correction for the strong motion records from Yibin Gaochang in Wenchuan earthquake is obtained.The response spectra were significantly different in high frequency and long period,but it had little effect on the middle period before and after correction.2.We can directly recognize spikes in pre-event and post-event of strong motion records.And PGA ratio,PGA/PGV ratio method,with PGA ratio method of the same station can be applied to identify complex spikes.A single point can be corrected by a single point adjustment method.However,the average adjustment method is more reliable.Trend line alternative correction can be used to adjust Multi points.Then the acceleration,velocity and displacement time history,absolute acceleration response spectrum,relative velocity spectra and relative displacement response spectra,Fourier amplitude spectrum have been analyzed before and after correction,we find that higher frequency part for response spectra and higher and lower frequency part for Fourier spectrum will be affected.