PSI - Issue 78

Fausto Alimenti et al. / Procedia Structural Integrity 78 (2026) 1326–1333

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and archive their results. In cases of negative static control outcomes, the managing entity is mandated to limit traffic on bridges through appropriate signage or physical access restrictions. Crucially, within its maintenance activities, the managing entity can directly undertake durability improvements and even static repairs without requiring a new static test, provided these interventions are for improving the durability or for repairs as specified in the relevant article of the decree. This established procedure has, over the years, enabled the elimination of many load restrictions on state roads that were previously imposed solely on numerical calculations without considering the actual behavior of the structure. This has significantly increased the economic efficiency of transport and provided a more objective orientation for investments in structural safety and durability. Since the static test has unlimited validity as long as correct maintenance is carried out over time, the maintenance plan for each structure becomes fundamentally important. The Province of Bolzano has implemented a standard maintenance plan provided to all designers, ensuring a uniform document for each bridge containing essential maintenance information. This document is also co-signed by the structural certifier, underscoring the close correlation between the structure's useful life, achieved through proper maintenance (a condition for certification renewal), and the validity of the certification. This systematic approach provides a proactive and well-documented framework for ensuring the long-term safety and usability of critical infrastructure assets. 5. Controlled demolition of bridges Controlled demolition of decommissioned bridges can be seen as an "autopsy" for structural elements, providing a unique opportunity to investigate structural defects and bring elements to failure under controlled conditions. Unlike traditional demolition, which often involves uncontrolled collapse, controlled demolition allows engineers and researchers to observe, measure, and analyze the behavior of structural components as they are subjected to extreme loads (see Fig.3). This important data can then be used to validate existing degradation models, compare numerical predictions with real-world performance, and gain a deeper understanding of how structures behave under various failure mechanisms (Tonelli et al., 2023). The evaluation of mechanical characteristics and degradation levels of existing bridges is a highly relevant topic today, particularly for aged structures. The controlled demolition of existing bridges represents an invaluable opportunity to deepen comprehension of their behavior, especially when degradation analysis is concerned. Full-scale experimental testing on reinforced concrete bridge beams, prior to their decommissioning, offers a unique opportunity to gather comprehensive data, including static and dynamic responses, and validate advanced numerical models (Darò et al., 2023). These full-scale tests involve both on-site investigations and subsequent laboratory experiments on elements extracted directly from the bridge. Such tests are complemented by Finite Element analyses conducted at various levels of detail, providing a robust integrated experimental-numerical research approach (Talledo et al., 2025). A critical aspect of aging bridges, particularly those constructed with prestressed concrete, is the condition of their prestressing systems. The rise in prestressed reinforced concrete bridges surpassing their projected lifespan has spurred increased attention from infrastructure managers and authorities toward monitoring and maintenance (Zorzi et al., 2024). Accurate understanding of bridge degradation, particularly concerning the prestressing system, is pivotal for efficient planning and prioritizing maintenance (Zorzi et al., 2024). Destructive and non-destructive testing (NDT) campaigns during controlled demolition provide essential information about the real condition of these systems. This includes assessing the mechanical properties of concrete and steel, the extent of corrosion, and the effectiveness of any previous repair interventions. NDTs are widely used in various engineering fields to provide reliable information with a relatively low impact on existing infrastructure (Kashif Ur Rehman et al., 2016; Mazzatura et al., 2023). Methods such as Digital Radiography, Ground Penetration Radar (GPR), and the Reflectometric Impulse Measurement Test are validated for the assessment of prestressing systems. Acoustic Emission (AE) is another effective NDT technique for detecting the initiation and propagation of cracks in concrete and the failure of steel wires (Tonelli et al., 2020).