Seismic Response of Hill Buildings with Base Isolation and URM Infills

RC frame structures resting on a hill slope exhibit diverse seismic responses in comparison with conventional buildings built on plain ground. Due to asymmetric structural configuration at different floor levels, the hill buildings attract additional lateral shear force and torsional moments in the structural members. Further, unreinforced masonry infills play a critical role in the energy dissipation during seismic excitements and are often neglected in the seismic analysis of buildings. Moreover, base isolation systems have also been shown to reduce the seismic vibrations in the buildings. Thus, in the present study, the effect of unreinforced masonry infill panels as well as a commonly used base isolation system, i.e. Laminated Lead Rubber Bearing (LLRB) on the seismic performance of two hill building configurations, viz. stepback and setback-stepback, was studied. All the configurations have been modelled using finite element software, and analysed by Response Spectrum and Non-linear Static Pushover method. The seismic parameters obtained from the numerical study were discussed in terms of base shear, fundamental time period, maximum top storey displacement and plastic hinge formation pattern in the building structure. Finally, the vulnerability and suitability of the different configurations against earthquake were compared in along and across slope directions.