Vulnerability analysis and seismic retrofit proposals for a RC school building: the case study of the "Minervini-Sisti" complex in Rieti

Protecting existing school buildings is a strategic priority in Italy, especially in high-seismicity regions like Rieti (Zone 2B). This paper analyzes the seismic vulnerability and the subsequent retrofitting proposal for the Minervini-Sisti school complex, a reinforced concrete frame structure built in 1974. The assessment was conducted through non-linear static analyses (pushover) using the N2 Method to compare structural capacity with site-specific seismic demand. The as-built study revealed critical deficiencies typical of 1970s construction: lack of strength hierarchy, absence of stirrups in beam-column joints, and brittle short column effects caused by infill walls. While the ductile safety index (IS-V) reached 0.87, the structure showed severe shear vulnerability and premature failures in vertical elements. The proposed retrofitting strategy employs steel jacketing for beams and columns, combined with specific reinforcements for unconfined joints. Post-intervention modeling shows that the solution is highly effective: increased confinement and ductility raised the brittle safety index to 81% and significantly lowered the seismic risk (PAM). These results demonstrate that targeted local reinforcements can successfully bring older school buildings up to modern safety standards.