This paper aims to examine the effect of seismic isolation on an important building which is located in a high seismic zone of India. Firstly, the building designed as a fixed base (FB) building as per the requirements of Indian codes and its seismically isolated (SI) version were compared using the non-linear static and dynamic analysis results. The damage states and the response parameters were compared. Secondly, the same building was designed as a fixed base building in the lowest seismic risk zone in India and seismically isolated to check if it can be used in the highest seismic zone or not. The results were positive which suggests that the member sizes can be reduced if seismic isolation is adopted, and hence the initial cost can be offset. To check for the design of elements, the vertical distribution of shear force coefficient was studied for the effect of higher modes and compared with Japanese code equation. In conclusion, it was seen that seismic isolation could be effectively used, particularly in important public buildings which need to be protected against earthquake damage as they serve important functions after an earthquake. Higher modal response using amplified shear coefficients can be applicable for Indian structures with unreinforced masonry infill (URM) walls.
Keywords: Seismic isolation, shear coefficient, higher modal response.