PSI - Issue 84

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

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1. Introduction Bridges play a fundamental role both in the ordinary management of territory and during emergencies (Nale et al., 2019). In particular, following catastrophic events, such as earthquakes and floods, these structures contribute to enhancing the resilience of surrounding areas. Alongside these infrastructures, hydraulic structures are also widespread in the Po Valley (Nale et al., 2025) and exhibit considerable typological heterogeneity, including weirs, spillways, retention basins, navigation channels, and lock-dams. Their primary purposes are flood attenuation and water supply for the agricultural sector, and inland navigation. In this area, flood risk is particularly significant, especially in light of recent flood events that have caused substantial economic losses and human casualties, within a context of increasing pressure due to climate change. As reported by Brath et al. (2023), between 2023 and 2024, four events with return periods exceeding 100–200 years were recorded. The global increase in flood-related damages observed over recent decades reinforces the common perception of a drastic rise in flood risk, often primarily attributed to climate change. However, the scientific community increasingly recognizes the role of anthropogenic pressures as well, such as the continuous expansion of urban and industrial areas within floodplains protected by levees, which can significantly increase potential damages, contributing to the so-called “levee effect” (Domeneghetti et al., 2015). At the international level, numerous studies indicate that aging hydraulic infrastructure and the non-stationarity of extreme hydrological events raise concerns regarding the ability of existing structures to ensure adequate safety levels (Fluixá-Sanmartín et al., 2018). For instance, an analysis of 33 dams in the United States (Cho et al., 2025), based on ultra-long historical series of uncontrolled water levels exceeding fifty years, revealed an increase in the probability of exceeding annual maximum levels and a growing number of dams at risk of critical overtopping. The study also identified six high-risk dams located near densely populated areas, highlighting the need for non-stationary approaches and proactive risk management measures. The hydraulic infrastructure in the Po Valley is also susceptible to seismic events, as the area is characterized by moderate seismic hazard. These systems are complex infrastructures, being composed of multiple structural and non structural components; the latter are essential for the proper operation of the infrastructure and include, among others, sluice gates, movable gates, emergency generators, control systems, and valves. Another distinguishing feature is the presence of bridges of various types (pre-stressed reinforced concrete, steel, truss, bascule), integrated into the hydraulic infrastructures. Beyond enabling vehicle transit, these bridges serve operational purposes, ensuring access to and functionality of the infrastructure itself. Their accessibility is therefore critically important. Bridges are subject to vulnerabilities related to limited maintenance, degradation phenomena such as corrosion, and extreme events. Under such conditions, partial or total collapse can have significant repercussions on the hydraulic infrastructure, potentially obstructing or damaging the movable devices (e.g., sluice gates) and compromising overall hydraulic functionality. This may result in a reduced flood attenuation capacity and, consequently, increase hydraulic risk during flood events. This study aims to analyze access and service bridges associated with hydraulic infrastructure, focusing on their potential failure mechanisms triggered by seismic and flood events and the resulting impacts on the functionality of hydraulic systems, with particular emphasis on movable gates. Partial or total collapse of bridges connected to these infrastructures may significantly impair hydraulic performance due to the accumulation of debris, which can damage and/or obstruct sluice gates, thereby preventing the proper conveyance of flow. This process leads to an increased hydraulic risk at these critical hydraulic nodes. Therefore, assessing the interdependence between bridges and hydraulic infrastructures is essential for a comprehensive evaluation of risk under multiple hazard scenarios, including floods, earthquakes, and degradation-related risks arising from material aging and inadequate maintenance. The infrastructures investigated in this case study are hydraulic infrastructures located within the territory of Ferrara, Italy. These systems exhibit a wide range of typologies and functions, as well as diverse configurations of the associated bridges. The territory of Ferrara provides a particularly suitable study area due to the significant variability of its infrastructure network and its combined exposure to seismic, flood, and degradation hazards.