Retrofitting through the loss-Based Earthquake engineering

Abstract The novelty of the research is the development of closed-form equations to assess the effective capacity of retrofitting interventions to reduce the seismic risk of existing buildings. The goal of the proposed procedure is to provide decision-making in the context of the Loss-Based Earthquake Engineering, whose purpose is the reduction of the seismic risk, which is herein computed through a monetary loss. The procedure consists of specifying performance targets (e.g. acceptable monetary losses, capital to invest, reduction of expected annual loss) and deriving engineering parameters, specifically the target fragility curves to achieve the established performance target. The identification of required fragility curves, in turn, allows to identify proper retrofitting interventions to mitigate the expected seismic loss. The method allows for estimating the maximum reduction of the annual average loss and the recommended capital to invest, accounting for the actual cost of the retrofitting alternatives and the nominal life of the building. In addition, it can be used to identify the payback period. With the aim of promoting the design procedure in the common practice, an existing reinforced concrete moment-resisting frame, retrofitted with three strengthening methods, is explored as case-study.