PSI - Issue 78

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

987

When seismic shaking occurs in the “weak” direction, early infill cracking and possible collapse can lead to rapid stiffness loss and damage concentration. Frames in one direction is noted as a typical trait of older Italian RC buildings that makes them highly vulnerable (Clementi et al. 2015). Italian classroom designs of the 1960s often used spans 5 6.5 m long to accommodate standard classroom widths. Corridors might add about 1.5-2.5 m large span if internal columns are used. This can cause the issue of adjacent “short beam” exposed to shear failure mechanism. Large atriums create discontinuity: the absence of a mid-floor in that zone leads to a flexible bay adjacent to regular bays, can induce soft-storey-like behaviour or amplify drift demands in perimeter frames around the atrium during seismic excitation. Looking at the in-elevation irregularity, educational buildings can have an open-plan ground level with fewer infill walls or long stripe windows, while upper floors have numerous masonry infilled classroom partitions. The absence of infills at ground level combined with the presence of infill masonry at upper storey significantly raises the probability of activating soft-storey collapse mechanisms. Moreover, architectural layouts induce the design of short columns due to the presence of infill masonry built with partial heigh with respect to the total column length, making them prone to brittle shear failures under seismic lateral loads. Tall window bands (to increase daylight in classrooms) are often used in this educational building-type, leading to this short column issue. Particular attention must be paid to the staircase and its placement within the building layout. A summary of these aspects is reported in the section “Results and Discussion”. 3. RC school building stock: collection and elaboration of the data The sample group of school buildings investigated in this study is located in the West side of the metropolitan area of Naples (Italy), predominantly in the densely populated districts of Pozzuoli, Bagnoli and Fuorigrotta. These areas, situated along the northern shore of the Bay of Pozzuoli, represent a critical portion of the urban fabric due to their high population density, rapid urbanization, and exposure to both tectonic and bradyseism – i.e., slow ground movements and gradual uplift associated to superficial earthquakes (Licata et al. 2019, Sandoli et al. 2023b). The building stock is composed of 57 RC school buildings erected during the 20 th century (specifically between 1950 and 1980). Structures are distributed across the coastal neighbourhoods inland toward the Campi Flegrei caldera. In Table 1, 30 of the schools composing the stock are listed.

Table 1. List of the 30 reinforced concrete school buildings composing the building stock studied.

School name

Andress

Number of floors [-]

Floor area [m 2 ] 1,150

School name

Andress

Number of floors [-]

Floor area [m 2 ]

I.C S. M. Paolo di Tarso Circolo Didattico di Monte di Procida I.C.S. M.D.P. Capoluogo-Vespucci

Via Lucullo, 10

2

I.C. Pergolesi

Via Giuseppe Marotta, 1 Via Severini, 2

1

1,245

Via Corricella 1

720

I.C De Amicis - Diaz

2

5,200

Via Torrione, 6 Via Cuma, 224 Via Torregaveta 68 Via Bellavista, 6 Viale Olimpico, 1 Via Formisano Via Fusaro, 150

2

460

I.C. V Comprensivo Artiaco

Via Artiaco, 98

3

1,990

IC Plinio

2

1700

Scuola Secondaria Statale Giacinto Diano

Via Solfatara, 35 2

4.500

Liceo Lucio Anneo Seneca

2

1,900

Plesso Trincone

Via Coste di Agnano, 1

2

755

Bacoli IC Plinio (via Bellavista) Scuola media Statale A. Gramsci Infanzia plesso Parco Sereno Bacoli IC Plinio (via Fusaro)

2

1,570

I.S.I.S. Guido Tassinari

Via Nicola Fasano, 13 Via Parini, 1

2

1,835

2

1,900

Scuola Andersen

1

130

1

1,000

Scuola Primaria Lucrino Via Turno

1

2,130

2

3,100

I.S.I.S. G. Falcone

Viale dell’Europa Unita

2

1,950