Probabilistic seismic performance assessment of tall RC buildings equipped with energy dissipator devices

Recent research has demonstrated the effectiveness of seismic isolators in high-rise structures, while studies on bracing reinforced concrete frames with buckling-restrained braces (BRBs) have also shown promising results. Combining these two techniques offers a potential solution to the challenges associated with isolating high-rise buildings. Bracing RC frames enhances key seismic characteristics, including reducing the structural period, increasing lateral stiffness and damping, and improving the seismic response at higher modes. This study conducts a probabilistic seismic performance assessment of isolated structures equipped with BRBs. Three-dimensional structural models with 15, 25, and 35 stories, incorporating special RC moment-resisting frames with BRBs, were developed. The design process was carried out in ETABS, and nonlinear dynamic analyses were performed in OpenSEES. The incremental dynamic analysis (IDA) curves were generated using nonlinear time-history analysis. This approach allowed for a comprehensive evaluation of both individual elements and the overall structural response under seismic loading . Seismic fragility curves were then developed based on the performance level drift thresholds recommended by HAZUS, covering four damage states. The results confirmed the superior performance and lower fragility of isolated structures equipped with BRBs compared to those without BRBs and isolation systems. The improvement in performance across the four damage states ranged from approximately 8–36 %. Furthermore, the seismic behavior of both structural elements and the overall system was significantly enhanced, demonstrating reduced strength and stiffness degradation in load-displacement diagrams and improved seismic performance in the IDA curves.