Assessment of Seismic Response Analysis of Base Isolated RC Building frame

The main purpose of this study is to reduce the story accelerations and story drifts due to earthquake ground excitation, applied to the superstructure of the building by installing base isolation devices (base isolators) at the foundation level and then to compare the different performances between the fixed base condition and base-isolated condition by using SAP-2000 software. In this study, the 4-storey and 12- Storey R. C. building which is located in seismic zone V is used as test model. The R. C. shear wall is provided to the superstructure of the building to get stiffer frame. Lead rubber bearing (LRB) is used in this study. For the second portion, response spectrum analysis and time history analysis are used on both of fixed base and base isolated buildings. All of analyses used in this study are done by using SAP-2000 software. In fixed base condition, all of structures are considered in elastic stage and in base-isolated condition, the superstructure of the building is considered in In this study, the static period of the building is 1.0 sec and it is lengthened to 2.0 sec, 2.5 sec and 3.0 sec at maximum earthquake level for comparative study. It is found that the more the period is lengthened, the lesser the story accelerations and story drifts of the superstructure above the base isolators and the displacement is increased with period of the building. The base shears in each direction are decreased significantly especially in 3.0 sec base-isolated building compared to the original building.