PSI - Issue 78

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

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To quantify the impact of corrosion on the mechanical properties of steel, a well-established experimentally derived relation between the mass loss due to corrosion and the reduction in yield stress was followed: ∗ =(1− ∙ [%]) (2) where ∗ is the yield stress of the corroded reinforcement, is the yield stress of the uncorroded reinforcement, is an empirical coefficient, and [%] is the percentage of corroded mass. Empirical values derived from various studies have been proposed for the coefficient. In particular, in the model, a of 0.0151 was employed, as proposed by (Imperatore et al., 2017) for uniform corrosion. To investigate the effect of corrosion, three scenarios were considered: a reference, non-corroded scenario (NC), and two different degraded scenarios, named Corrosion 1 (C1) and Corrosion 2 (C2). In the reference model, the constitutive curves “Confined Concrete” and “Unconfined Concrete” (Figure 4a) were adopted.

(a)

(b)

(c)

Fig. 4. (a) Constitutive laws for concrete; (b) Fiber element with corrosion 1; (c) fiber element with corrosion 2. In the first deterioration scenario, namely C1, the mechanical parameters were reduced by assuming a corrosion penetration depth, X , of 0.5 mm. The degraded material properties ∗ and ∗ were then calculated according to Equations (1) and (2), respectively, and the nonlinear model was updated accordingly. The “Degraded Unconfined Concrete 1” curve was used for both the concrete cover layer and the ineffective confined concrete (Figure 4b). In the second scenario, namely C2, based on photographic evidence of the structure, a higher corrosion penetration depth of 1 mm was assumed. Additionally, portions of the concrete cover that have spalled off were removed, and a reduced confinement effec t was considered. Therefore, the “Reduced Confined Concrete 2” curve was employed for the confined core and the “Degraded Unconfined Concrete 2” curve for the external layers (Figure 4c).