Probabilistic Seismic Performance Assessment of RC Frames Retrofitted with External SC-PBSPC BRBF Sub-structures

A new external retrofitting sub-structure is proposed, namely, self-centering precast bolt-connected steel-plate reinforced concrete buckling-restrained-brace-frame (SC-PBSPC BRBF). Based on the 3D numerical model and stiffness-based design method, five retrofitting scenarios are performed on a deficient frame building to compare the upgrading effects. Probabilistic seismic performance assessments are carried out for different scenarios, and the whole evaluation process is divided into four parts (i.e., hazard, demand, capacity, and risk). The analyses illustrate that using the external retrofitting sub-structure, the structural demands are obviously reduced with lesser annual exceedance probability, the structural capacities are significantly improved with lower damage state probability, and the structural losses are sharply lessened with more controllable probability. The external SC-PBSPC BRBF is a promising retrofitting sub-structure and the research provides references for practical applications in the earthquake-prone regions.