PSI - Issue 84

Federica Di Criscio et al. / Procedia Structural Integrity 84 (2026) 1023–1030

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associated with the predicted exposure time obtained from the corrosion model. In this way, time-dependent degradation profiles are generated. These profiles offer an outlook on the expected performance decay and can be continuously updated: should future inspections indicate a corrosion rate that differs from the initial estimate, the curves can be adjusted accordingly, following an adaptive digital-twin-like approach. 3. Illustrative application 3.1. Description of the case-study bridge The case study consists of an archetypal bridge proposed by Gentile et al. (2021), derived from a statistical analysis of representative Italian bridges. The overall geometry of the bridge is illustrated in Fig. 2. The structure comprises four simply supported spans, each 30 m long, with a deck formed by precast prestressed concrete I-girders equipped with 7-wire tendons. The RC piers are 10 m high and are characterized by a hollow polygonal cross-section (Fig. 2b). Material properties are assigned according to nationwide distributions of mechanical parameters for existing bridge stock. A concrete compressive strength equal to 26.8 MPa is adopted, while a steel tensile strength equal to 370 MPa is considered. The bridge is assumed to be located in L’Aquila (high-seismicity zone). The seismic demand is derived considering a 100-year service life, soil class B, and “use category” IV (i.e., strategic infrastructure), returning a peak ground acceleration PGA = 0.45 g.

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Fig. 2. Italian Archetype bridge: geometrical details of (a) the whole structure and (b) the RC pier (after Gentile et al., 2021)

Since the bridge is archetypal and no real inspection records are available, deterioration is modelled by defining three alternative hypothetical degradation scenarios (i.e., low, medium, and high; Fig.3a), each accompanied by a corresponding defect form. Each scenario is associated with a specific Defect Score (DS), subsequently converted into a quantitative defect index. For the RC piers, the three DS levels are linked to corresponding percentages of cross sectional area loss  %. Moreover, different possible locations for the corroded section are considered along the pier height, as shown in Fig.3(b). For the prestressed concrete girders, the qualitative defect index is mapped into three distinct levels of maximum pitting depth in the prestressing tendons, max . Low High Medium

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Fig. 3. Degradation scenarios: (a) alternative levels of damage intensity (after Gentile et al., 2021); (b) locations of the corroded cross-section.