PSI - Issue 78

Marco Postiglione et al. / Procedia Structural Integrity 78 (2026) 984–991

986

seismic provisions (Perrone et al. 2020). Figure 1 presents an extract and adaptation of the data reported in the same work Perrone et al. (2020). It illustrates that the majority of school buildings in Italy have less than three storeys and are predominantly composed by RC frames with infills masonry or URM structures. Specifically, panel (a) provides a subdivision of the Italian school building stock, based on a database developed by the Eucentre Foundation (www.eucentre.it) within the framework of the “Progetto Scuole”. Panel (b) displays the distribution of RC and URM structures as a function of the number of storeys. Two-storey buildings are the most common among both URM and RC schools, followed by single-storey structures (i.e., about one-third of the RC stock) and a smaller fraction of three storey buildings (about 17%). Structures with four or more storeys are rare, representing fewer than 14% of RC schools nationwide.

10 15 20 25 30 35 40 45 50

RC URM

47.5

41.9

39.7%

32.4

20.4%

24.6

21.3

39.9%

17.4

12.1

0 5

5.5

5.7

1.7

1

URM RC Mixed/Other

one-storey two-storey three-storeyfour-storey five-storey >= six storey

Percentage of Italian schools [%]

(a)

(b)

Number of storey [-]

Fig. 1. Structural typology and number of storeys in Italian school buildings. Panel (a): distribution by structural type based on th e “Progetto Scuole” database [1 4]. Panel (b): percentage of RC and URM buildings by number of storeys. Data adapted from Perrone et al. (2020).

The Campania region of Italy experienced a surge in school construction during the 1960s, at a time when much of the area had not yet been classified as seismically active. The first national seismic design regulations applicable to ordinary buildings were introduced in 1974-1975 and subsequently strengthened after the 1980 Irpinia ’s earthquake (Sandoli et al. 2023a). As a result, RC schools constructed before 1980 generally lack seismic detailing, whereas those built in the post-1980 period incorporated, at least nominally, seismic design provisions (Ruggieri et al. 2021): this led to the creation of a wide stock of RC educational buildings that are now acknowledged to be structurally deficient. For this reason, the construction age emerges as a primary indicator of seismic vulnerability (Carofilis et al. 2020, Sandoli et al. 2021]. To address this, national programs (e.g., the Italian Education Ministry’s Anagrafe Edilizia Scolastica database) are actively classifying and assessing the existing school inventory to support prioritization of mitigation interventions. The architectural layout of mid-century Italian school buildings typically follows standard educational schemes that standardized the structures. Many of them have rectangular plans with classrooms aligned along one or both sides of a corridor. This often yields elongated, near-rectangular plans (aspect ratio about 3:1 or more). When a single corridor is present on one side of classrooms, asymmetric condition emerged. Buildings with L, T or U plan shapes experience stress concentrations in some areas of the building, causes plan irregularity induce to torsional response during earthquakes unless seismic joints were provided (rarely provided). Another recurrent feature is the presence of wide entrance atriums or double-height halls. Usually, primary RC frames were oriented in one direction only, with the transverse direction relying on masonry walls or small linking beams. Such one-directional frame layouts is symptom of vulnerability : the “weak” direction may have significantly less ductility due to the absence of frame. 2.1. Structural-typological features affecting seismic performance