PSI - Issue 78

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

985

Keywords: School buildings; Reinforced concrete (RC); Archetype classification; Seismic assessment; Fragility analysis.

1. Introduction School buildings represent a fundamental component of community resilience, providing not only educational services but also acting as shelters and emergency facilities in the aftermath of seismic events (Di Ludovico et al. 2023). Observations coming from recent seismic events occurred in Italy and other countries have consistently highlighted the vulnerability of school infrastructures, affected by damage patterns often comparable to those recorded in residential buildings (Dolce et al. 2021). A tragic emblematic case is represented by the collapse of the school building of San Giuliano di Puglia during the 2002 Molise earthquake, which resulted in the death of 28 people, and which underscored the pressing necessity to assess and retrofit the aging school building stock (Borzi et al. 2013). This structural fragility has far-reaching social and economic consequences, since damage to school facilities disrupts educational continuity and deprives communities of safe, accessible spaces during emergencies. In the Italian context, a large share of school buildings was constructed during the economic expansion that followed World War II, particularly between the 1950s and the 1970s. This is especially evident in the western metropolitan area of Naples, including districts like Pozzuoli, Bagnoli, and Fuorigrotta which experienced significant urban growth in that period. The majority of reinforced concrete (RC) school buildings erected during this timeframe were designed in accordance with early seismic codes, namely the Regio Decreto 2229/1939 and subsequent Ministerial Recommendations issued between 1957 and 1978. These provisions did not incorporate key principles of modern seismic design, such as ductility design, confinement detailing, and appropriate reinforcement anchorage (Del Gaudio et al. 2020) As a consequence, many of these RC school structures are characterized by regular moment-resisting frames, shallow foundations and unreinforced masonry infill walls, with limited capacity to withstand lateral seismic forces due to inadequate (or missing) considerations of horizontal forces in the design process. Despite a growing body of research on the seismic vulnerability of RC residential buildings based on national databases such as Da.D.O. (Dolce et al. 2019) comparable investigations focused on school buildings remain relatively limited (Di Ludovico et al. 2023, Giordano et al. 2021). Given the unique functional and structural characteristics of school facilities, the development of school-specific fragility models is of paramount importance (Di Ludovico et al. 2022, Ruggieri et al. 2021). This study presents an expert-judgment approach inherent the definition of the structural typological attributes of RC school buildings typical of the Italian school building stock, with particular emphasis on those present in the western suburbs of Naples (Italy) considered as representative archetypes of the National territory. Starting from analysing architectural features, the aim is to establish correlations between structural-typological features, age of construction and expected seismic performance (Sandoli et al. 2021). Particular attention is paid to typical characteristics of school buildings – i.e., number of storeys, construction age, plan configuration, diaphragm type, structural system, material properties, presence of irregularities in plan or elevation, etc. – which significantly influence their structural behaviour. Taking inspiration from National and International scientific studies on structural typological classification, as well as on seismic assessment and fragility modelling, this study identifies representative archetypes of Italian RC school buildings of mid-20th-century. These archetypes are critically examined pointing out their strengths and weaknesses aimed at developing fragility analysis able to support prioritization strategies for seismic risk mitigation. 2. RC Italian school buildings (1950-1980): an overview In the aftermath of the World War II, Italy experienced a substantial increase in student population which generated an urgent demand for new school facilities throughout the 1950s to 1980s; thus, about thousands of buildings were rapidly constructed often based on standardized or experimental design solutions (Giannetti 2016). RC construction gradually became the prevalent solution for school buildings starting from the 1960s, whereas earlier schools were predominantly masonry-based (Cattari et al. 2024). Until 2003, over two-thirds of Italian territory was not formally classified as seismically hazardous, implying that a substantial number of schools were originally designed for gravity loads only and subsequently reclassified as located in seismic-prone areas due to codes updating over the years. Approximately, the 67% of the Italian school building stock were built before 1975, before the introduction of modern