PSI - Issue 78

Andrea Nettis et al. / Procedia Structural Integrity 78 (2026) 1404–1411

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function with the seismic hazard curve, the expected loss function is obtained. Finally, the expected annual losses (EAL) are computed by integrating the area under the expected loss function. 4. Case-study application 4.1. Description The analysis focuses on a single-column pier with a circular cross-section. To account for modeling and analysis uncertainty, geometric properties were treated as deterministic, whereas the key mechanical properties previously described were modeled as random variables. The analysis focuses on a single-column pier with a circular cross section. Geometric dimensions were assumed to be deterministic, reflecting the typically low variability in these parameters when original design documents are available and accurate on-site measurements are conducted. In terms of defect localization, this study focuses on the presence or absence of corrosion in the lower portion of the pier. The reference pier considered in the study features a circular cross-section with a diameter of 2 meters and a total height of 8 meters. The reinforcement layout includes 55 longitudinal bars with a diameter of 20 mm and transverse stirrups of 16 mm diameter spaced at 100 mm intervals. A lumped seismic mass, representing the tributary mass of the superstructure and pier cap, is applied at the pier top. This mass, assumed to be 500 tons and treated as deterministic, does not influence the pushover response but plays a key role in defining the axial load acting on the pier cross-section. 4.2. Results This section presents the results of the fragility analysis and loss assessment for the case study, illustrating how the output from the CV-based corrosion detection and classification framework can support the evaluation of corrosion induced degradation in RC piers and its impact on seismic performance. It is worth noting that two scenarios have been analyzed: Pristine condition and Corroded condition with high corrosion localized at the base. The fragility curves in Fig. 3 clearly highlight a significant increase in seismic vulnerability across all damage states under corrosion conditions. Specifically, at a 50% probability of exceedance, the IM values decrease by approximately 11% for the slight damage state, and by 65–70% for higher damage states. This indicates that localized corrosion at the pier base more than doubles the fragility compared to the pristine condition.

Fig. 3. Fragility Curves derived for each DS for Pristine (left) and Corroded (right) conditions.