PSI - Issue 84

Marco Nale et al. / Procedia Structural Integrity 84 (2026) 329–336

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(d) (f) Fig. 5. Defects detected in bridges associated with hydraulic infrastructure in the Ferrara territory. (e)

3.2. Failure Mode Identification To assess the potential vulnerabilities of bridges interacting with the hydraulic infrastructure of the Ferrara area, a Failure Modes and Effects Analysis (FMEA) was carried out. This methodology enables the identification of critical structural components, potential failure modes, their main causes, and the effects on the functionality of the hydraulic system, thereby providing a robust basis for risk-informed management and maintenance planning. The decision to adopt the FMEA approach, rather than relying solely on the current national guidelines (MIT, 2022), is motivated by the exceptional conditions and strong interdependence between bridge and hydraulic infrastructure in the study area. Indeed, the current guidelines fail to account for hydraulic infrastructure among the entities whose infrastructure is crossed. Consequently, the attention class is determined without considering interactions with the hydraulic infrastructure. Given the critical role that such infrastructures play in flood risk management, it is therefore necessary to calibrate this aspect not only based on the importance of the bridge in terms of traffic flows and serviceability, but also by considering accessibility and the category of the hydraulic infrastructure, as defined by the current regulatory framework (MLLPP, 1904). Existing literature has been extensively documented, categorized, and analyzed bridge-related defects, particularly for prestressed reinforced concrete bridges (D’Amato et al., 2025) and bridge bearings (Masi et al., 2025). Understanding the relationship between the possible failure modes and their effects on hydraulic infrastructure is therefore essential. Inspections allowed the identification of the relevant failure modes and their associated effects or impacts. Failure causes are associated with both natural hazards, such as seismic events, flood occurrences, and scour processes, and factors related to material degradation and inadequate maintenance. The effects on the hydraulic system include partial or total obstruction of channels and gates, reduction of bridge load-bearing capacity, increased flood risk, and impairment of navigability. Observed failure mechanisms include the fall of debris from the bridge deck, piers, and abutments made of reinforced concrete (Figs. 5a,b), primarily due to material degradation, resulting in the partial obstruction of some gate inlets and a consequent reduction in their hydraulic functionality. Additionally, the overturning of masonry parapets in masonry arch bridges (Fig. 5c), triggered by a flood wave, caused the partial obstruction of the bridge associated with the hydraulic structure, leading to an increase in flood risk. This analysis enables the identification of priority criticalities requiring maintenance and monitoring interventions, providing a comprehensive framework for understanding the interactions between bridge failures and the overall hydraulic system performance. In particular, the comparison between well-preserved components and severely degraded elements enables estimation of the potential impact of each failure mode on the overall hydraulic risk.