Civita di Bagnoregio (VT). Applicazione di un metodo speditivo per la valutazione e la riduzione del rischio sismico di aggregati storici

Current Italian law concerning seismic risk assessment and reduction is at an advanced stage regarding cultural heritage but is minimally applied in private buildings. Multidisciplinary studies have continuously remarked how the vulnerability of historic masonry-aggregate constructions increases due to many causes other than degradation and damage, such as their intrinsic characteristics, including, stratified development, continuity of use, state of abandonment or absence of maintenance. Due to their problematic and often unpredictable behaviour during an earthquake, aggregate buildings are not frequently tested and there is a lack of appropriate instruments for their interpretation. There is a need, firstly, to invest more in studies to produce models similar to reality and secondly, to make trustworthy interpretations and predictions on behaviour and damage in the case of an earthquake. The current research focused on the proposal for a simplified method concerning seismic vulnerability assessment of aggregated buildings in historical centres. The final purpose is to support local administrations and/or owners of the buildings in strategic decision making, to define priority lists regarding structures more in need of specific analysis and, potentially, of focused interventions. The experiment was undertaken in Civita di Bagnoregio (Viterbo), a historical centre which was gradually abandoned due to earthquakes and hydrogeological instability.