PSI - Issue 78

Emanuele Maiorana et al. / Procedia Structural Integrity 78 (2026) 57–64

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1. Introduction

Existing masonry structures typically exhibit high seismic vulnerability due to several factors: low material stiffness (Young’s modulus), inadequate connections between floors and load-bearing walls, the heavy mass of masonry walls, and flexible floor diaphragms. Numerical studies confirm that floor stiffness plays a critical role in determining both resistance capacity and collapse mechanisms (Mendes & Lourenço, 2015). This vulnerability has prompted extensive research and regulatory attention worldwide, particularly for culturally significant buildings (Alam et al., 2012; Hassan et al., 2022; Lang, 2002; Thermou & Pantazopoulou, 2011), with Italy establishing specific legislative frameworks (D.P.C.M. 09.02.2011; Decreto 456) and methodological guidelines (Lagomarsino & Cattari, 2015). In recent decades—though recent relative to the age of Italy’s building stock—a succession of regulations has emerged to define and assess seismic capacity (e.g., O.P.C.M. 3274, 3362, 3519; DD.MM. 58-65; D.P.C.M. 09.02.2011; D.M. 29.12.2017; D.M. 17.01.2018). Notably, O.P.C.M. 3274 mandated seismic safety evaluations for all schools, while D.M. 29.12.2017 required public entities to quantify the seismic safety index of school buildings as a prerequisite for state funding, whether for seismic retrofits or energy upgrades. Complementary guidelines (Circ. C.S.LL.PP. 7; Decreto 456; Linee Guida al D.M. 14.01.2008) and research (Lagomarsino et al., 2002; D’Ayala et al., 1999) provide operational frameworks for compliance. A persistent challenge lies in historic buildings, where stratifications and modifications—often protected for conservation—frequently preclude achieving modern safety standards. Consequently, even rigorous assessments may yield overly conservative results. To address this, current standards and literature emphasize simplified approaches for rapid vulnerability screening, combining field inspections, experimental tests, and nonlinear analyses (Domaneschi et al., 2021; Marasco et al., 2021). Such methods prove invaluable for large-scale evaluations, particularly for school infrastructure. Equally critical are studies systematizing substructures or macroelements to enable probabilistic collapse assessments (Augusti et al., 2001), offering a pathway for statistical analysis of seismic risk. The assessment procedure comprises five key phases: 1) Acquisition of geotechnical and seismological data, including subsoil classification and seismic hazard parameters; 2) Geometric surveying and in-situ investigations to determine structural properties required for numerical modeling of the building complex; 3) Structural analysis using computational methods to evaluate both global and local safety for each considered limit state; 4) Seismic safety verification and risk assessment, quantified through the seismic classification indicator; 5) Preliminary identification of localized interventions for seismic improvement. The methodology employs a comprehensive 3D model encompassing all structural units within their physical boundaries. This approach is particularly suited for high-density urban contexts with interconnected structures, as it accurately captures seismic action redistribution and quantifies the seismic mass fraction supported by each macro element (Lagomarsino & Cattari, 2015). Such detailed behavioral understanding is essential for optimizing conservation efforts while ensuring seismic safety. The building under seismic assessment represents a typical historical construction complex (Boschi et al., 2018), featuring multiple construction phases. The structure comprises three above-ground levels with partial basement areas. Its architectural evolution began with the central cloister's construction in 1480, followed by successive expansions continuing into the early 20th century. Currently owned by the Municipality of Vicenza, the building houses the Dame Inglesi Paritaria school (established 1837) under the management of the Mary Ward Foundation. The superstructure consists of masonry walls, while floor systems predominantly feature traditional wooden "river beam" construction. These floor assemblies lack sufficient rigidity for diaphragm action and cannot effectively couple opposing wall facades. The wooden roof structure covers the entire top floor with characteristic sloping profiles. Although foundation documentation is unavailable, on-site investigations and the vertical structural typology suggest continuous masonry 2. Intervention methodology 3. Building survey