PSI - Issue 78

S. Cattari et al. / Procedia Structural Integrity 78 (2026) 1577–1584 S.Cattari et al. / Structural Integrity Procedia 00 (2025) 000–000

1580

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across Italy – it will be possible to proceed to the modelling phase of the most recurrent interventions identified through data analysis and ultimately quantify the impact of such interventions. a) As-built condition MSN2 FLR TR

Pre-1919

b)

DS1

DS3

DS5

2 storeys

c) Fig. 2. Set of fragility curves in the as-built and retrofitted condition 2-storeys masonry buildings (a), and percentage increase in median PGA for selected damage states (b) (from Follador et. al 2023) 3. Available database A standardized format has been defined for the unified collection of information necessary to investigate the most widespread retrofit techniques at the national scale. At present, the database includes 12 URM structural units and 27 RC structural units (some example in Fig. 3), of which 30 (11 URM + 19 RC) were reprocessed by UniGE based on projects provided by the engineering firm Studio Tecnico Baffo S.r.l (made available by PoliMI), and 9 (1 URM + 8 RC) are available to UniBAS. These buildings are distributed across Italy, primarily located in regions with medium-to-high seismic risk (51% - Lazio and Basilicata), 21% in high seismic risk zones (Umbria and Abruzzo), and the remaining 28% in medium-to low risk area (Lombardia, Liguria, and Toscana). The intervention strategies designed planned for the current sample of school buildings mainly involve complete rehabilitation (62%), while the remaining 38% consists of seismic upgrading only. Seismic performance assessments of the interventions were carried out mainly using nonlinear static analysis for URM, whereas RC structures were evaluated predominantly through linear dynamics analysis. RC buildings were mostly constructed starting from the 1970s, whereas URM buildings date back to periods prior to the 1960s (Fig. 4). URM are predominantly two-storey buildings, while RC structures are generally three-storey. These trends reflect the characteristics of the school building stock at the national level, particularly for URM buildings. In contrast, regarding RC structures, the database includes a higher proportion of taller and older buildings compared to the national sample (Cattari et al. 2024). This may be attributed to the greater seismic vulnerability typically associated with such characteristics, which likely led to these buildings being prioritized for intervention. Most of the buildings exhibit plan irregularities; it is in fact common to find school buildings with “L”-shaped, elongated rectangular, or more complex plan configurations. The load-bearing system of the RC buildings in the sample are predominantly composed of bidirectional frame structures or mixed frame-shear wall systems; only 20%