Italian Seismic Damage Prevention Policies for the Built Heritage: Efficacy and New Perspectives

Earthquakes that occurred in Italy in the last 50 years—in particular the most recent seismic events which affected Northern and Central Italy in 2012 and 2016–17—have shown the high intrinsic vulnerability of existing structures. Many historical structures and old town centers suffered partial or total collapse, even in the presence of seismic improvement interventions. This fact underlines, on the one hand, the wrong definition of the seismic hazard that in most cases largely exceeded the design one, and on the other hand, the limitations of seismic preventive policies prescribed by the Italian building code, especially for listed buildings. Furthermore, sequences of shocks with similar magnitude are typical of Italian earthquakes. In these conditions, namely seismic multi-events conditions, the existing buildings suffered progressive and severe damage, overcoming the life safeguard and collapse limit states defined by the national prescriptions. This condition results in a high level of risk for operators acting in the post-earthquake phase, since aftershocks may cause further collapses of already damaged buildings. Severe damage was observed also in almost all the historical listed buildings. In the seismic multi-event context, especially in Central Italy, the damage evolution brought to the complete loss of historical structures. Italian regulations prescribe very limited seismic retrofitting works for listed buildings, that cannot even cope with the first shock of the seismic sequence. In light of this, new seismic preventive policies should be adopted, at least in areas with moderate-high seismic hazard, to safeguard people’s lives and avoid the loss of cultural heritage. Moreover, strong shock sequences, occur frequently in Central Italy; thus, new preventive policies would be required to limit damage accumulation and, therefore, reconstruction costs.