Observed damage and simplified risk assessment of Italian masonry bell towers struck by past seismic events

This study provides a discussion using a database of historic masonry bell towers struck by past Italian earthquakes, which is the result of an extensive literature review on post-earthquake reconnaissance reports and scientific publications. The observed damage is analysed to give an insight into the seismic behaviour and vulnerability of this peculiar building typology. To this end, a macro-scale approach is adopted, two distinct damage mechanisms are identified and evaluated, and a damage index for each tower is computed. This enables to develop the damage probability matrices, providing the frequency of damage occurrence. Moreover, vulnerability and fragility curves are derived to help the prediction of future possible damage scenarios. The developed vulnerability and fragility curves are compared with the mean damage observed in the samples included in the database. This comparison allowed to check the robustness of rapid procedures today available in the field of seismic risk assessment for the specific case of historic masonry towers.