Nonlinear structural analysis and design of reinforced concrete building with base isolation system

In the recent years, the base-isolation systems are gaining great attention as a solution to protect the structures against the seismic risk. The main role of such system is to separate the structure from its foundation and then eliminate the adverse effect of the earthquake motions. In this study, an existing 9-storey reinforced concrete (RC) building having three bays on the x-direction and five bays on the y-direction direction were considered as a case study model. As a base isolation, friction pendulum type system was used. The seismic performance of the base isolated structure was investigated and compared with the existing one. In this regard, the effectiveness of using base isolation in protecting the building against the seismic actions was examined under different earthquake accelerations. The structures were modeled by means of a finite element method and evaluated by nonlinear time history analysis. The performance characteristics of the fix-based and base isolated RC structures were determined in terms of the storey displacement, interstorey drift ratio, base shear, and columns bending moment. Based on the results of the nonlinear analysis, a substantial improvement in the seismic response of the based isolated structure in comparison to the existing one was observed.