Comparative Probability Based Seismic Safety Assessment of Base Isolated Building Frames

Abstract Seismic fragility curves are used to assess the probability of vulnerability of structures at various damage states. This research deals with the effects of different isolation systems on the seismic safety of a two-dimensional reinforced concrete moment-resisting frame. The reference structure was a hotel building in California. A comparative probability-based seismic safety of building components was investigated on the superstructure hypothetically fitted with various isolation systems. In this regard, two categories of isolation systems including, rubber-based and friction‐based were selected here. The High Damping Rubber Bearings and Friction Pendulum Systems were considered here. Incremental Dynamic Analyses were carried out for a suite of earthquake records to develop the fragility curves considering modeling, demand, and capacity uncertainties. Based on the main results, the influence of seismic isolation systems on the reduction of failure probability of building rather than fixed base (un-retrofitted) model was observed. Moreover, the High Damping Rubber Bearings were more reliable than Friction Pendulum Systems in the limit states studied. No significant discrepancy was, however, seen in the performance of building fitted with isolation systems at higher damage states.