PSI - Issue 78

Valentina Buonocunto et al. / Procedia Structural Integrity 78 (2026) 169–176

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1. Introduction Masonry buildings represent a significant share of the existing building stock in Italy, particularly in small towns and historical city centers. Many of these structures were constructed before seismic design regulations, using traditional materials and construction techniques. As a result, they have been frequently found to have high seismic vulnerability due to poor mechanical properties, insufficient connections between structural elements, and irregular configurations (Lagomarsino & Giovinazzi, 2006; Augenti and Parisi, 2010; Lagomarsino et al., 2013; Parisi and Augenti, 2013). To evaluate seismic risk at regional or national scale, it is essential to classify buildings into consistent typological groups, commonly referred to as taxonomies. A building taxonomy provides a structured description of key features, such as masonry type, floor system, construction period, and structural layout (Brzev et al., 2013). This information is critical for the identification of representative building archetypes and structural models (Ravichandran et al., 2021), derivation of fragility models used in large- scale risk assessments (D’Ayala et al., 2021 ; Buonocunto et al., 2023), and development of appropriate risk mitigation actions based on either traditional or innovative technologies (Losanno et al., 2022). Several studies have proposed classification systems for masonry buildings at the local scale, often based on field surveys or post-earthquake damage data (Vicente et al., 2011; Del Gaudio et al., 2019). In Italy, nationwide databases such as the 2011 ISTAT census (ISTAT, 2011) and technical survey forms from the GNDT project (GNDT, 2000) offer valuable sources of information on building characteristics. However, a unified and statistically sound taxonomy for masonry buildings across the entire country – but relying upon regional data – is still lacking. This paper proposes a new nationwide taxonomy for Italian masonry buildings, based on available census and technical data. The classification incorporates key parameters such as construction period, wall typology, and floor system. Through statistical analysis of the CARTIS database (Zuccaro et al., 2015), the study identifies common structural configurations and regional patterns. The ultimate goal is to support seismic vulnerability assessment and risk mitigation strategies in a more systematic and data-informed manner. The proposed taxonomy is designed to interface with probabilistic seismic risk models, allowing the assignment of appropriate fragility functions to each building class. These functions can be derived from empirical data, analytical models, engineering judgement, or hybrid methods available in the literature (e.g., Lagomarsino et al., 2013; Del Gaudio et al., 2019). In addition, the spatial distribution of the classified masonry stock supports the development of exposure models at regional scale, enabling the analysis of multi-risk scenarios and prioritization of interventions in areas subjected to high seismic The development of a regional taxonomy for Italian masonry buildings should consider both historical construction practices and their evolution through the regulatory and technological transformations of the 20th century. The selected classification criteria aim at reflecting key aspects influencing seismic behaviour and to ensure compatibility with existing national databases such as ISTAT census data, GNDT forms, and CARTIS inventory. The following parameters were identified as essential: • Age of construction : Buildings were grouped into six construction classes: pre-1919, 1919 – 1945, 1946 – 1961, 1962 – 1971, 1972 – 1981 and post-1981. These time periods correspond to significant turning points in Italian building regulations, especially regarding seismic codes ( e.g ., Regio Decreto 431/1927, Legge 64/1974), and mark clear shifts in materials and construction techniques ( e.g ., from stone to brick, from wooden to RC floors) • Wall typology : Based on the CARTIS classification and national guidelines such as Commentary No. 7/2019 (MIT, 2019), masonry assemblages were categorized into six types, ranging from irregular stone masonry (A1 – A2) to cut stone masonry, brick masonry, and ashlar masonry with regular squared units. Each wall type is associated with distinct mechanical properties and failure mechanisms, particularly under seismic loading. • Floor system : Diaphragm behaviour greatly affects the seismic response of masonry buildings. Floor systems were classified into flexible ( e.g ., timber beams), semi-rigid ( e.g ., steel beams), and rigid ( e.g ., RC slabs). A special category was introduced for vaulted floors, frequent in historical masonry buildings (pre-1919), typically limited to ground levels. hazard levels (Buonocunto, 2025). 2. Criteria for taxonomy modelling