PSI - Issue 78

Lorenzo Ciccarelli et al. / Procedia Structural Integrity 78 (2026) 1428–1435

1429

worldwide have highlighted the vulnerability of these structures (Gara et al., 2025). In order to overcome this critical issue, exacerbated by the lack of a unified and comprehensive European regulation, the Italian government has introduced specific guidelines for the multi-risk assessment of existing bridges and viaducts. These guidelines, initially published by the Italian Superior Council of Public Works in 2020 and updated in 2022, once that the operational instructions from “Agenzia Nazionale per la Sicurezza delle Ferrovie e delle Infrastrutture Stradali e Autostradali” (ANSFISA) were included, aim to standardise risk classification, safety assessment, and structural health monitoring (Salvatore et al., 2024). To this end, the guidelines propose a multi-level approach that integrates surveys, inspections, preliminary assessments, detailed structural analyses, and safety checks, addressing a wide range of potential hazards. This paper presents a significant case study described in Section 2, which was assigned a "HIGH" attention class, according to (MIT, 2020) following census and inspection activities. This classification is due to its considerable seismic hazard and vulnerability, in addition to the presence of significant defects. Under this classification, the asset necessitates comprehensive safety assessments and in-depth investigations into its geotechnical and/or structural characteristics, alongside the execution of routine and extraordinary periodic inspections, and the deployment of monitoring systems. In accordance with the guidelines, the bridge was therefore subjected directly to Level 4, namely detailed safety verifications, upon the generation of a Finite Element Model (FEM), which are detailed in Section 3 of this paper. Section 4 discusses the performed analyses, exploring the progression of structural damage under seismic actions. Particular emphasis is addressed to the impact of ongoing degradation phenomena and their influence on the bridge’s behaviour across various deterioration scenarios. Finally, the main conclusions are presented in Section 5. 2. The studied bridge The study evaluates the structural safety of the bridge (Figure 1a), which forms part of the A2 highway and is located in the province of Cosenza, Calabria region, in the south of Italy. The structure is estimated to have been designed in 1965 and subsequently built-up in 1968. No original design documents were available. A design drawing dated 1990 was found, concerning an intervention at the deck ends and the planned inclusion of anti-seismic restraints. However, these restraints were not observed during the inspection, leading to the assumption that the proposed works were not executed.

(a)

(b)

(c)

Fig. 1. (a) overview; (b) defect caused by oxidized and corroded reinforcement in the pier; (c) schematic longitudinal profile.

The bridge features an isostatic structural scheme, comprising decks composed of four pre-tensioned reinforced concrete (RC) beams simply supported on the piers. The total span is 243 meters, consisting of seven spans, each 9.60 meters wide, with an average span length of 32.50 meters. The deck slab is made of prestressed concrete.