PSI - Issue 78

Giuseppe Santarsiero et al. / Procedia Structural Integrity 78 (2026) 560–567

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The paper also discusses the potential cause-effect relationships among observed defects, such as the impact of inadequate waterproofing systems on reinforcement corrosion, offering practical insights for optimized asset management, for instance, by building priority lists that help in the funds allocation for risk mitigation purposes (Sasmal et al. 2007), including detailed structural assessments according to the current building code (MIT 2018). 2. Methodology To transform qualitative inspection data into actionable insights for asset management, it is essential to adopt a quantitative framework capable of synthesising various types of damage information. Level 1 inspections, although visual in nature, provide a detailed defect registry for each beam. However, translating this information into comparative metrics requires the use of structured indices that integrate severity, extent, and intensity of observed phenomena. For this purpose, a Degradation Index was developed, which enables the objective evaluation of each beam’s condition, allowing comparisons within and between structures. This approach supports a more informed prioritisation of inspection and maintenance activities, aligning with modern principles of infrastructure management (FHWA 2016; Scalbi et al. 2022). A degradation index (IDeg) was defined to quantify the condition of each beam. It is the weighted average of the severity levels of all detected defects. The severity G of each defect is weighted by both its extent and its intensity reported in the inspection form (Fig. 1), according to the following expression: = ∑ ∙ = 1 1 ∙ 2 (1) where G i is the severity level of the i -th defect, k 1i is its extent, and k 2i is its intensity. The degradation index is computed for each beam by summing the contributions of all defects identified in the inspection sheet. The index allows for a quantitative comparison across beams and bridges. Additional synthetic indicators are introduced: • IDeg p,c: sum of all beams’ degradation indices averaged over the bridge span number; • IDeg p,t: sum of all beams’ degradation indices averaged over the total number of beams in the bridge. These indices are used to evaluate the spatial distribution of deterioration and support targeted interventions (Santarsiero and Picciano 2024). Moreover, the two indices are meant for comparison purposes among different bridges and make decisions regarding prioritization of further actions depending on the bridges’ condition. 3. The case-study bridge set The analysed dataset comprises six viaducts located in the Basilicata region (Southern Italy), all constructed across the 1970s, according to the 1962 code (Ministry of Public Works 1962). They are all positioned along the same road and within a limited geographical range — the average distance between bridges is approximately 5 km (exact location, road or bridge name cannot be disclosed to protect sensitive information). Their location at an altitude of about 400 m a.s.l., in a relatively homogeneous environmental context, is of particular interest: all structures are exposed to similar climatic, thermal, and hydrological conditions, which ensures that differences in degradation are not primarily due to environmental variability, but rather to structural and maintenance-related factors. These common environmental conditions — including moderate winter temperatures, frequent rainfall, and occasional freeze-thaw cycles — can significantly affect the durability of reinforced concrete elements, especially when compounded by insufficient drainage. Moreover, the bridges are all affected by the use of de-icing salts during winter. Indeed, all bridges show clear evidence of poor water management: many joints are damaged or ineffective, downpipes are missing or obstructed, and deck waterproofing layers are often incomplete or degraded. As a result, rainwater is not adequately drained, leading to percolation through the deck and direct exposure of the beams — particularly edge beams — to moisture ingress.