Reconstruction policies: explicitating the link of decisions thresholds to safety level and costs for RC buildings

In (FEMA 308 in Repair of earthquake damaged concrete and masonry wall buildings, Prepared by ATC for the Federal Emergency Management Agency, Washington DC, 1998) a general framework facilitating decisions on appropriate course of action (accept damage, restore, or upgrade) for damaged buildings after an earthquake was presented. Such Performance-Based Policy Framework relies on performance index of the building in its intact and damaged state and on the relative performance loss as significant indicators for repair and/or upgrade decisions; however, no specific guidance for the establishment of PL and IP thresholds governing damage acceptability was given. This paper proposes an improvement of the PBPF introduced in FEMA 308 by providing it with a set of performance thresholds that can be established based on a clear quantitative approach and presents a set of tools for its practical implementation with reference to Reinforced Concrete frame buildings. In addition to the Repair and Repair and Retrofit options, also the Demolish one is introduced, because it corresponds to a not infrequent decision in case of severely damaged buildings in European-Mediterranean regions. Criteria to establish decision thresholds IP and PL are proposed that allow to clearly connect them to reconstruction costs and probability of failure of the building in the intact and damaged state. Finally, a case study demonstrates the application of the hypothesized policy framework for a Municipality in southern Italy and investigates on the effects of varying decision thresholds on the total reconstruction costs and mean safety level for the considered building stock.