Study Of Complex Site-Buildings Seismic Dynamic Interaction Simulation By Spectral Element Method

With the continuous advancement of urbanization in China,buildings and population in large cities are gradually densely concentrated,which greatly increases the risk of casualties and property losses caused by earthquake disasters.In order to meet the requirements of building resilient cities and strengthening risk prevention and control in the governance of megalopolis,it is necessary to accurately simulate and evaluate the earthquake damage of urban buildings.Theoretical studies and seismic observations show that local topography,seismic input and site-building dynamic interaction have important effects on the dynamic responses of sites and buildings.In this paper,based on the spectral element method,the simulation of dynamic response of buildings with complex accurate seismic wave input and consideration of sitebuilding complex interaction is realized,and the seismic response of complex sitebuilding system is simulated.The main work is as follows:1.Based on the spectral element method program SPECFEM3 D,this paper carried out secondary development,and developed the input module of dynamic stiffness matrix method for calculating wave field and the nonlinear dynamic time history analyze module of multi-degrees of freedom system into the original program.An accurate program for simulating the seismic response of complex site-buildings system under the excitation of precise seismic input is obtained.By comparing the calculated results with the previous numerical simulation results and experimental results,the correctness of the method is verified.2.The dynamic response of basin-buildings theoretical model was simulated by using the secondary development spectrum element method program,and the sitebuildings interaction effect was analyzed.The results show that the basin effect of the site has a decisive influence on the global dynamic response.While the site-buildings interaction changes the spatial distribution of ground motion and the buildings’ dynamic response amplitude in a certain extent.Generally,the increase ratios of the ground surface and the top floor of the building peak acceleration is between-26.6%and 20.5% after considering the interaction.When the fundamental frequencies of the buildings close to the main frequency of ground motion,the peak accelerations of the site and the top floor of the buildings would decrease significantly under the interaction,and the reduction rate can reach 30.1% and 45.5%.3.The dynamic response of site-building system of Tianjin University Beiyangyuan Campus was simulated by using the secondary development spectrum unit program,and the site-buildings interaction effect was analyzed.The damage of buildings under the action of frequent and rare earthquakes was evaluated.The results show that the site-buildings interaction may have a significant impact on the dynamic response of individual buildings.In the case of most earthquakes,the increase ratios of the peak displacement of the top floor of buildings after considered the interaction float in the range of-17.6%～17.8%,and the damage condition of buildings is intact.In the rare earthquake case,the peak displacement increase ratios of the top floor of the buildings float in the range of-4.4%～35.2%,and the damage degree of the buildings is moderate.Seismic simulation and earthquake damage assessment provide effective reference and reasonable suggestions for buildings seismic defenses.