Risk–driven fragility evaluation of reinforced concrete block walls subjected to blast hazard

The steady recurrence of blast events involving civilian buildings constitutes an ever present challenge for structural engineers worldwide. Current design methodologies addressing the blast resistance of masonry buildings are mostly grounded in deterministic approaches, which neglect several sources of uncertainty affecting the structural response––including variability in material properties, geometry, and accuracy of predictive numerical models. To capture these uncertainties, fragility analysis is routinely practiced in the field of seismic design, while it is often set aside when explosion–induced loads are considered, in favour of simpler, empirically based techniques. The present study is aimed at quantifying the fragility of reinforced concrete block walls subjected to blast overpressure from live ammunition, as a way to objectively gauge their safety conditional on the occurrence of a specified threat. The results of such analysis are expected to foster the future development of blast resistant design guidelines that align with limit states philosophy.