PSI - Issue 84

1028 Federica Di Criscio et al. / Procedia Structural Integrity 84 (2026) 1023–1030 To select the values of  % and max for the different scenarios, the corrosion process is modelled following the approach described in §2.2. This approach provides the evolution of  % over time based on the model proposed by Val & Melchers, (1997), identifying the onset of corrosion, the initiation of cracking, and the spalling of the concrete cover (Figure 4a), as well as the expected maximum pitting depth over time (Figure 4b). Based on the combination of the defect forms and the predicted corrosion process, consistent values of  % and max can be assigned to the various DS. In the present case, for the piers,  % was assumed equal to 5%, 10%, and 15%, while max was set to 0.2, 1.3, and 2.5, corresponding respectively to the low, medium, and high damage scenarios.

(a) (b) Fig. 4. Time-dependent evolution of: (a) μ% , showing the onset of corrosion, cracking, and cover spalling; (b) maximum pitting depth max 3.2. Results and discussion For the pier, Fig. 5(a) and Fig. 5(b) illustrate, respectively, the global force-displacement relationships obtained for a fixed hinge location at the base under varying corrosion levels, and the corresponding curves for a fixed corrosion level of 10% as the position of the degraded section varies. As expected, the advancement of the corrosion process leads to a progressive reduction in flexural strength and ductility capacity, accompanied by a slight decrease in initial stiffness (Fig. 5a). This trend underscores the significant influence of corrosion-induced cross-sectional loss on the nonlinear flexural response. Yet, the minimum flexural capacity occurs when corrosion affects the base section (Fig. 5b). As the corroded section is shifted to higher elevations, the flexural capacity increases; however, this improvement is offset by a reduction in global displacement ductility due to a reduction of the effective cantilever length. Within a cantilever length range of 7–10 m (measured from the pier top), the plastic hinge tends to form at the most deteriorated section, consistent with a mechanism governed by the corrosion-induced reduction in flexural capacity. When the corroded section is located above this range, it no longer governs the plastic hinge formation: even considering the maximum corrosion level, the plastic hinge develops at the base. In this case, the nonlinear behaviour does not differ from the intact configuration.

(a) (b) Fig. 5. Force–displacement capacity curves considering: (a) fixed plastic-hinge location at the base and varying corrosion level μ%; and (b) fixed corrosion level and varying position of the corroded section.