Fitting And Bridge Seismic Response Analysis, Based On The Phase Difference Spectrum Of The Artificial Ground Vibration

As the traveling wave effect, local site and partial coherent effects etc., the input seismic waves of the different supporting points is varied in the seismic analysis of the large-span structure. So, the consistent seismic seismic input or only consider the wave propagation of traveling wave input method is significantly different from the actual situation. Therefore, the structural seismic response analysis of multi-point is necessary. And the quantity of limited seismic records can not meet the requirements of antiseismic analysis, which is also unsuitable to complex and different site situations. Therefore, the engineering growing concern the study of ground motion for the spatial and temporal variability of artificial wave technology and the related the input mode.ground motion record is a significant non-stationary process, which not only in the time-amplitude intensity distribution, but also in terms of frequency composition. Currently, the traditional wave fitting processes makes the frequency of non-stationary greatly weaken, which oriented towards the goal of of response spectra for the intensity non-stationary fitting. The simulation of ground motion base on phase difference spectrum and the seismic analysis of long span arch bridge have been researched.Accordingly, this paper studies the following:Firstly, the coherence function theory and empirical model was introduced. Then, the bedrock coherency model was discussed in detail, with which a new coherency model established which suitable to various site characterization combined with the results of Hao.Secondly, with the Response spectrum-Power spectrum conversion formula the power spectrum of rock has been fitting. And then based on the transfer function, the power spectrum matrix has been derived at the bridge site. Then the fitting acceleration time history based on phase difference spectrum been tested, the results reflect that it has property of partial coherence effects as the real seismic waves and the traveling wave effect and non-stationarity characteristics in time-frequency domain. Thirdly, the input mode in structure seismic analysis in wave input or multi-support excitations was discussed, in which the application of the input of the acceleration (large mass method) mainly researched.Fourthly, the bridge model of Ji'an was analysed with the input of fitting acceleration time history in this thesis and time-traveling wave effect. The results show that when the span is large and the site soil properties are different greatly, it is unsafe that considering the effect of wave only and the seismic response analysis of multi-point excitation is needed.