Energy-based seismic strengthening design of non-ductile reinforced concrete frames using buckling-restrained braces

This paper presents the application of an energy-based seismic design procedure to strengthen non-ductile reinforced concrete frames using buckling-restrained braces. An experimental study was conducted to examine the seismic behavior of a large-scale non-ductile RC specimen strengthened with BRBs. For the analytical study, a large number of dynamic analyses of non-ductile systems that were strengthened using ductile elements with varying strength were conducted to investigate the overall response behavior. Finally, a practical strengthening design method was presented. The method was based on the modified performance-based plastic design approach. A design example was presented. Nonlinear pushover and nonlinear time history analyses were conducted to evaluate the performance of a non-ductile RC frame strengthened with BRBs. Both the test and analysis results indicated that BRBs significantly increased the stiffness, lateral force capacity and energy dissipation. The analysis results of the strengthened frame exhibited significant response improvement in terms of structural performance and story drifts. The results were used to verify the effectiveness of the presented design approach.