A Simplified Procedure to Select a Suitable Retrofit Strategy for Existing RC Buildings Using Pushover Analysis

Over the past ten years, the development of analytical procedures to accurately evaluate the seismic performance of existing buildings has gathered the attention of researchers. This has resulted in the publication of several standards, which, however, inadequately cover the issue of retrofit strategy selection. In the present article, a procedure that allows a comparison of available strategies in order to select the optimum solution for an existing deficient building is proposed. The procedure is based on calculating the pushover curve for the unstrengthened structure. A capacity spectrum is then estimated assuming different retrofit scenarios, which is then used for the evaluation of the strategies. The latter is based on criteria that assess the main structural system characteristics and how each solution benefits them. The final step of the procedure introduces simplified rules that allow the approximate design of each retrofit solution, which allows the evaluation of their applicability. The proposed procedure was applied to two idealized buildings with different structural systems. Results obtained indicate that less effective or inapplicable rehabilitation strategies were properly detected. Thus, the results were considered acceptable in terms of identifying the possible optimum strategy, which, however, should be verified with a detailed design of the retrofit system.