Fragility assessment of the Italian masonry school building asset for risk evaluation at national scale

Seismic risk and scenario assessments at large-scale provide important science-based tools to support governments and civil protection departments in investment policies and emergency planning. In this framework, school buildings are particularly significant due to the consequences of their damage or collapse and their relevance, as public buildings, in emergency planning. The evaluation of risk requires the definition of its components, i.e., hazard, exposure and vulnerability. To assess the seismic vulnerability of masonry school building assets, this paper presents the fragility curves derived for 265 building types, based on the Italian school building census. Parametric analyses were carried out on 14 representative prototype schools, using a mechanics-based model which considers both in-plane and out-of-plane mechanisms. More than 7500 sample fragilities were calculated and linearly combined to obtain fragility curves representing the Italian taxonomy of masonry school buildings. A macro-seismic heuristic model from the literature was then calibrated to derive a fragility set for each school type, for five damage states, from slight damage to complete collapse. Finally, the paper compares the outcome fragility curves and fragility sets from the literature for residential buildings, highlighting the specificities of school seismic vulnerability. Indeed, masonry school buildings are frequently characterized by intrinsic geometric deficiencies due to significant inter-story height and great distance between transverse walls, both affecting the out-of-plane response and, therefore, the overall seismic fragility.