The inherent seismic vulnerability of existing masonry buildings is well-known; within these assets, school masonry structures may exhibit even higher levels of vulnerability than ordinary buildings, due to function-related architectural peculiarities such as greater inter-storey heights, larger spacing between walls, more elongated or irregular floor plans, main façades with more and wider openings, internal walls with very limited openings.

As part of the National DPC-ReLUIS project 2022-2024 (WP4 - MARS-2), the authors have already analyzed the seismic fragility of a stock of 101 school buildings located in the Friuli - Venezia Giulia region, in their current, unreinforced masonry (URM) configuration (Giusto et al., 2025). The analysis was based on a simplified mechanical-analytical procedure, to determine the seismic fragility curves, and accounted for key structural features, such as the geometry, the masonry characteristics, the gravity loads and the restraints.

This paper presents preliminary results of ongoing research (DPC-ReLUIS 2024-2026) aimed at assessing the impact of retrofitting interventions based on the Composite Reinforced Mortar (CRM) technique on the seismic fragility curves of the same building stock. In particular, the main features of the CRM reinforcement technique, the methodology developed to adapt the analysis procedure to these interventions, and the comparison between the fragility curves in the as-is and retrofitted conditions are discussed.

These results could be very useful in decision-making during the implementation of large-scale mitigation policies, as they can help predict the impact of the analyzed intervention at a territorial scale, as well as in comparison with other types of interventions, for which similar evaluations could be developed.

Giusto, S., Boem, I., Alfano, S. et al. Derivation of seismic fragility curves through mechanical-analytical approaches: the case study of the URM school buildings in Friuli-Venezia Giulia region (Italy). Bull Earthquake Eng 23, 2611–2646 (2025). https://doi.org/10.1007/s10518-025-02137-6