Seismic Analysis of Fixed Based and Base Isolated Building StructuresDownload PDF
Non-structural components are sensitive to large ground motion which produces floor accelerations, velocities, and displacements. During an earthquake, the building produces this motion, resulting in peak floor accelerations higher than the peak ground acceleration. Thus earthquake ground motion can cause significant or severe structural damages. The use of base isolation is the best method to reduce interstorey drift and floor accelerations. A new type of base-isolation system is developed here for a multi-storey reinforced concrete building. This work deals with modeling and analysis of 13-storey rigid jointed plane frame for two cases. First case is fixed base and second case is base isolated. Modeling and analysis is done using E-TABS software for Bhuj earthquake ground motion records. Maximum vertical reaction is obtained from analysis in E-TABS software. Using this vertical reaction and total mass of structure lead rubber bearings are designed manually. Time-history analysis is carried out in order to evaluate floor response, accelerations and displacements during a ground motion. This paper intends to demonstrate how an isolation system can be efficient, evaluating its effectiveness for the building in terms of maximum shear force, maximum bending moment, base shear, storey drift and storey displacement reductions.
Keywords: Base isolation, lead-rubber bearing, time-history analysis, reinforced concrete building, storey acceleration, floor displacement, storey drift, base shear.