Abstract Past destructive earthquakes have highlighted the vulnerability of substandard reinforced concrete (RC) buildings that do not comply with seismic design codes. To ensure safety of the occupants and mitigate the losses, these buildings should be urgently retrofitted or rebuilt. This study evaluates conventional retrofitting techniques (integration of new shear walls, and RC jacketing of existing columns), and innovative techniques (fiber-reinforced polymer confinement, and RC thin jacketing with FRP confinement of existing RC columns) in enhancing seismic performance and reducing potential losses. For this purpose, an existing RC moment frame building representing the common characteristics of substandard RC frame buildings in Türkiye was considered. After performing seismic assessment of the building and demonstrating its unsatisfactory performance, retrofit designs were made to satisfy the target seismic performance limit (life safety). A series of nonlinear structural analyses were performed in accordance with the incremental dynamic analysis technique for both the as-built and the retrofitted states. The typical characteristics of substandard buildings (i.e., low strength concrete, lack of confinement, tendency of longitudinal bars to buckle, etc.) were considered during the numerical modelling. Fragilities were generated for immediate occupancy , life safety , and collapse prevention limit states. As the ground motion intensity measure, the Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) were utilized. Furthermore, cost-benefit analyses were conducted to assess the relative effectiveness of alternative retrofitting techniques in terms of mitigating potential losses. All retrofitting strategies were found to become economically beneficial within a short time horizon, ranging between 3 and 7 years.
Unal et al. (Wed,) studied this question.