Sugli impatti della correlazione struttura a struttura dei danni per la valutazione del rischio sismico regionale

One of the main challenges in implementing the performance-based earthquake engineering framework and computing risk and associated consequences on a regional scale is incorporating the structure-to-structure damage correlation in the analysis. This study investigates the impact of considering such correlation through a case study involving the assessment of mid-rise concrete frame buildings in the province of Caserta in Southern Italy. An analytical method is proposed to estimate the correlation, using the results of Incremental Dynamic Analysis (IDA) on equivalent Single-Degree-of-Freedom (SDOF) oscillators. This approach is applicable to various earthquake scenarios and is less computationally demanding than using the results of Multiple-Stripe Analysis (MSA) on full 3D models of the buildings, which were also considered as the benchmark case. The study compares the results of both approaches, finding that while the proposed method tends to overestimate the correlation, it still yields more accurate damage estimates than cases where this correlation is neglected entirely. Additionally, the study confirms that including the damage correlation in the analysis significantly impacts the probability distribution of the number of damaged buildings, particularly by increasing the risk of large-scale damage. Incorporating this aspect in the analysis can lead to more accurate damage and loss estimates, allowing to plan improved strategies for risk preparedness and mitigation.