Dynamic Elastic-plastic Anaysis Of Isolation Structure Under Rare Earthquake

Isolation structure is a new type against earthquake disasters, which favored by more and more structural engineers, and there exist some problems to be solved, such as how to determine the seismic coefficient rationally. Those problems will be researched to verify the strength and ductility of the isolation structure in the different seismic coefficient under rare earthquake in this paper.In this paper, a seven stories isolated frame structure, including isolation layer, which is designed according to current codes, procedures and standards based on understanding the development and application of isolation technology in domestic and abroad. A reasonable upper structure corresponding to different seismic coefficient is designed by SATWE software. Then ETABS which is a large finite element software, has been used to analyze isolation effects in inter-mediate earthquake, and it shows that it can reach the expecting effect of seismic reduction through changing the parameters of isolation pad and stiffness of the upper structure, at the same time the displacement of isolation layer, tensile and compressive stresses of isolation pad also conform to the requirements of the specification. Then the nonlinear analysis and performance assessment for3D structure software PERFORM-3D has been used to establish nonlinear model and then this model on the basis of nonlinear time history analysis under rare earthquake is analyzed. Quantitative evaluations are given in the entire structure comparing with energy dissipation, the state of the component performance and the maximum demand and capacity ratio D/C in different seismic coefficient. Finally, a lot of conclusions about scale into the nonlinear of the upper structure with the different seismic coefficient are obtained, and a suggestion is that the reduction seismic fortification intensity of upper structures should not be greater than1degree under8degrees (0.30g) has been put forward. Next, this model is analyzed with horizontal ground motions of one-direction, two-direction, three-direction into the nonlinear model, the results show that multi-directional seismic combined effects on structure cannot be ignored.Finally, some suggestions are obtained by the summary of above.