PERFORMANCE BASED SEISMIC DESIGN OF REINFORCED CONCRETE BUILDING FRAMES

Abstract

Buildings and other structures must be designed to perform satisfactorily to withstand earthquake, provide safety to human lives, and to minimize the economic losses from the damages, if any. Current code-prescriptive forcebased design intends to provide strength and ductility to structures for life safety, but actual performance is never assessed. Structures designed with a code-based approach experienced extensive damage leading to enormous economic loss and high repairing costs in the past earthquakes (e.g., 1994 Northridge and 1995 Kobe earthquake). With a view to enhancing safety and reducing damage, i.e., emphasizing the performance of structures accelerated the development of performance-based seismic design. This study aims at designing reinforced concrete building frames following performance-based earthquake engineering approach. An archetype eight storied RC building has been selected and a frame has been analyzed and designed following the seismic design approach of the BNBC 2020. Nonlinear time history analyses using suitable earthquake ground motion records have been performed to assess the performance of the code designed building frame. The selected ground motions have been matched with acceleration response spectra of required earthquake hazard levels to check the selected performance objectives. Story drift, an indicator of damage, has been selected as an engineering demand parameter to quantify performance. Then, the frame has been designed using the performance based seismic design approach meeting the selected performance objectives. Finally, the effects of base flexibility on the responses of the building in force-based and performance-based design approaches have also been assessed. The present study will help designers, owners, and stakeholders to make intelligent decisions in designing new or strengthening existing buildings to achieve the required performance of the structures.