Enhancing Seismic Resilience of Pre-Code RC Building: A Fragility Assessment

A braced frame significantly enhances structural efficiency and provides essential lateral stiffness. Incorporating retrofitting elements transforms the structure into a proficient system capable of achieving higher elevations. Self-centering energy dissipating braces (SCEDs) are among the most effective seismic resistance frameworks due to their ability to dissipate energy under lateral seismic loads and enhance retrofit designs. This study examines the seismic vulnerability of a pre-code reinforced concrete moment-resisting frame equipped with SCEDs through seismic fragility curves. The structural analysis includes brace implementation and soft story condition assessment at the ground level. Non-linear analyses are conducted to evaluate the seismic performance of an eight-storey and six-storey structure with single diagonal braces. Incremental dynamic analysis is then performed using a set of accelerograms compatible with UAE site conditions. Maximum story drift is used as the demand parameter, and drift ratios for various seismic performance levels—immediate occupancy, life safety, and collapse prevention—are selected based on HAZUS guidelines. The IDA curves are then used to generate seismic fragility curves through structural reliability relations.