Seismic Performance Research Of Base Isolation Frame Structure

Earthquake damage to the structure is caused by the forced vibration due to ground motion. The basic principle is that by setting a base isolation system to make the base layer and the upper structure can do limited flexibility slide,Thereby reducing the level of stiffness of the structure, to extend the vibration period of the structure, effectively reduce the structural acceleration response in the earthquake. Most of the seismic energy is consumed by the isolation layer, the upper structure only slightly translation. This article use the finite element software SAP2000 creating multiple layers of reinforced concrete structure, to discussion on the seismic performance and damping effect of the base isolation structure through nonlinear static analysis and nonlinear history analysis.Firstly, elaborated the basic principle and the motion characteristics of the Isolation Technology, describes the common seismic isolation’s device classification, structure and mechanical properties. Thereby establishing base isolation mechanical model and dynamic equilibrium equation, deduced the isolation system dynamic equilibrium equation. Provide a reference for the subsequent nonlinear history analysis.Secondly, Using the nonlinear analysis software SAP2000 to establish a three-dimensional nonlinear model in taking the non-linear property of the base isolation layer and the upper structure into account, History analysis was carried out on base isolation model under the 8 degree rare earthquake seismic waves of EL-Centro, TAFT and Artificial wave. Make comparison with theresults of the corresponding non-isolated structure, to judge the effect of damping and seismic performance of isolated structure. The results show that under the seismic force, the acceleration, displacement and an interlayer shear layer of the base isolation structure has a very large reduction in compared to the non-seismic isolation structure, greatly reduced the effect of horizontal seismic forces on the structure, improved the overall seismic performance of the structure.Finally, carry out static nonlinear analysis of the isolated structure by pushover based on sap2000. Give way to lateral load applied to the base isolated structure, verify the reliability of the lateral loading by contrast with the non-linear time history analysis results. In addition, study the law of plastic hinges’ appear, distribution and development of the isolation frame structure by analysis the Pushover results. Identify the structure’s weaknesses that may exist, to provide the basis for the design of isolated and isolated structures seismic performance evaluation.