PSI - Issue 78

Simone Reale et al. / Procedia Structural Integrity 78 (2026) 1657–1664

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1. Introduction Harsh environmental exposure conditions can lead to severe deterioration phenomena on RC structures, including bridges. Corrosion represents the main deterioration phenomenon in RC members, leading to non-constant performance of structures over time and including a number of facets. Corrosion negatively affects several aspects, such as reinforcement section, steel and concrete mechanical properties, confinement level, cyclic bond capacity, shift of failure mode from ductile to brittle and can lead to concrete cracking and spalling due to the expansion of corrosion products. Given the complexity of the phenomenon, predictive modeling of the long-term performance of RC structures requires carefully considering corrosion-induced deterioration in order to provide realistic and reliable results. Significative research effort has been dedicated to this issue in the past. Alipour et al. (2011) studied the long term performance of deteriorating RC bridges considering corrosion-induced deterioration through a relatively simplified approach including uniform reinforcement section loss and steel yielding strength reduction. Shekhar et al. (2018) provided recommendations for modeling ageing bridges exposed to chlorides, discussing uniform and localized steel area loss, loss of cover and core concrete strength and reduction of steel yielding and ultimate strength. Xu et al. (2020) discussed the numerical modeling of deteriorating shear-critical columns. Dizaj and Kashani (2022) proposed and validated a modeling technique including critical aspects such as Low-Cycle Fatigue (LCF), inelastic buckling and bond-slip. Reale et al. (2025a) proposed a refined and practical corrosion damage modeling strategy, validated it against experimental tests carried out on corroded bridge piers and presented an application discussing the long-term seismic performance assessment of an RC bridge (2025b). Given that the numerical model development represents one of the key modules of the Performance Based Earthquake Engineering (PBEE) framework, the assumptions related to the level of detail of corrosion damage modeling affect the results of seismic assessment. The present contribution investigates the implications of progressively more refined corrosion damage modeling strategies on the long-term seismic performance assessment of RC bridges. The extensive numerical investigation is carried out following state of the art PBEE principles and considering a prototype bridge exposed to chloride attack. Chloride diffusion and corrosion propagation are characterized probabilistically through Monte Carlo simulation, accounting for the inherent uncertainty of the process. The results of the seismic assessment are systematically scrutinized through fragility curves and failure rates related to four damage states. 2. Corrosion Damage Modeling Strategies Four progressively more detailed corrosion damage modeling strategies have been considered for the present research, as summarized in Table 1. Strategy 1 only includes reinforcement section loss to model the effects of corrosion. Steel section loss is modeled according to Ghosh and Sood (2016). Assuming hemispherical pits (Val, 2007), the residual area in presence of pitting A R,P and the pit width a(t) can be estimated as per Equations (1)-(4): ( ) = 2 ( )√1 − ( ( ) 0 ) 2 (1) , = { 02 4 − 1 − 2 ( ) ≤ √ 2 2 0 1 − 2 √ 2 2 0 < ( ) ≤ 0 0 ( ) > 0 (2) 1 = 1 2 [2 ( ( ) 0 )( 0 2 ) 2 − ( ) | 0 2 − ( ) 2 0 |] (3)

2 = 1 2 [2 ( 2 ( ( ) ) ) ∙ ( ) 2 − ( ) ∙ ( ) 2 0 ]

(4)

Where D 0 is the pristine bar diameter and p(t) is the maximum pit depth.