PSI - Issue 84

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P.A. Maglietta et al. / Structural Integrity Procedia 00 (2026) 000–000

1112 © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Paolo Andrea Miglietta et al. / Procedia Structural Integrity 84 (2026) 1111–1118

Peer-review under responsibility of the scientific committee of the Conference Keywords: Bridge pier; Reinforcement corrosion; Functionality curves; Seismic analysis.

1. Introduction Bridges and viaducts are essential components in transportation networks, playing a pivotal role in both social and economic development. In recent decades, several bridge collapses occurred, primarily due to structural deficiencies associated with inadequate maintenance and building material deterioration (Alonso Medina et al., 2022). These episodes may result in economic and human life losses; therefore, stakeholders are interested in spending resources to enhance the resilience and reliability of infrastructure. Furthermore, as infrastructural assets play a fundamental role in the case of seismic emergencies, structural assessment, service-life prediction and performance monitoring have become essential to ensuring an adequate safety level in case of accidental or extreme events (Blasi et al., 2025). In Italy, the infrastructural heritage mainly consists in reinforced concrete (RC) bridge built more than 50 years ago, according to outdated design codes. Several phenomena regarding long-term mechanical response and seismic performance were not considered during design, leading to urgent need of monitoring and structural retrofit. Regarding RC facilities, creep, reinforcement corrosion, concrete cracking may result in a sharp reduction of the load-bearing capacity and ductility of the entire structure. It is well recognized that degradation phenomena are governed by both construction detailing (e.g. material properties, concrete cover thickness) and weather parameters, including the relative humidity (RH), environmental temperature and the frequency of rainfall events. As such parameters are deeply affected by inherent uncertainties, the structural assessment carried out according to a deterministic approach may lead to unrealistic, too conservative or unconservative evaluation of the structural safety level (Miglietta et al., 2025). Herein, a predictive analysis was conducted on an archetype pier, representative of elements in RC bridges with simply supported girders. The aleatory uncertainties associated with input parameters were also addressed in the study. The seismic capacity of the pier was evaluated in terms of dissipated energy capacity under lateral loads, predicting its evolution over a 100-year service life. The effects of deterioration phenomena, including rebar corrosion, concrete cracking and creep, were considered by modifying both the bending moment-curvature relationship and shear force shear strain at each time step as function of the degraded mechanical properties of the materials. A Push-over seismic analysis of the pier was also conducted to compute the evolution of the load bearing capacity over time. 2. Literature review Concrete matrices create an alkaline environment with a pH of approximately 11.5. Under such conditions, steel reinforcement is surrounded by a thin protective layer. However, when carbon dioxide (CO 2 ) penetrates the concrete pores, the alkalinity is neutralized through a process known as carbonation, resulting in the destruction of the protective film and the onset of steel corrosion, as reported in (Pedeferri and Bertolini, 2000). Hence, the service life of RC elements and structures may be divided into two distinct stages: the initiation phase and the propagation phase, as suggested by Tuutti’s model (Tuutti, 1982). The former is primarily governed by the concrete cover thickness and the carbonation rate, while the latter is mainly influenced by the steel corrosion rate. 2.1. Degradation models The carbonation reaction is governed by several factors, including RH, number of rainfall days per year, cement type, time of curing and CO 2 content. A comprehensive formulation to describe carbonation penetration over time is provided by the Model Code (CEB-FIP, 2010), as expressed in Equation (1):