Seismic Performance of a Base-Isolated Demonstration Building

This paper presents the dynamic analyses and seismic performance of a base-isolated demonstration building (BIDB). This building was designed and built in Indonesia in accordance with the Indonesian Seismic Code (ISC) and the Uniform Building Code (UBC) provisions for isolated buildings. The building is a four-story reinforced concrete frame with masonry infill walls supported on 16 high damping natural rubber (HDNR) isolators attached to the superstructure using recessed connections. The building superstructure was modeled using both three-dimensional (3-D) and two-dimensional (2-D) frame models. The isolators were modeled as a combination of linear springs and viscous dampers, whose properties were determined from testing. Time-history (TH) and response-spectra (RS) analyses performed on this building demonstrated that this newly developed isolation system, designed specially for low axial pressure applications, was effective in protecting the building superstructure from earthquake forces for all seismic risk levels being considered. The total isolator displacement obtained using the TH and RS approaches is also compared and discussed.