Bridges are vital components of any existing infrastructure, enabling essential links for transportation and commerce. In Italy, a nation renowned for its historical bridges, the importance of proper risk classification, safety assessment and monitoring of existing structures is of paramount importance. Risk classification involves categorizing bridges into different classes based on their potential risks and deterioration levels. The fundamental purpose of risk classification is consistent across guidelines: to prioritize bridge inspections and maintenance efforts based on risk levels. Once bridges are classified according to risk, safety assessments and continuous monitoring are performed to evaluate their structural integrity and overall long-term safety. The methodologies for safety assessment can differ significantly among guidelines, highlighting the influence of regional factors, such as construction materials, design practices, and environmental conditions. However, the common goal is to ensure the safe operation of existing bridges by identifying deficiencies and prescribing necessary interventions. Monitoring techniques can range from visual inspections to advanced sensor networks and non-destructive testing methods. In Italy various guidelines and standards have been developed to address these concerns, to ensure the safety and longevity of its bridges. The actual guidelines inspections for existing bridges include those by the Italian Ministry of Infrastructure and Transport (MIT), which plays a central role in setting the national guidelines and regulations for bridge safety in Italy. MIT is responsible for overseeing the safety and maintenance of publicly-owned bridges in Italy, providing a comprehensive framework for risk classification, considering factors such traffic loads, material degradation and level of defectiveness. On the other hand, other manual exist, such those provided by Autostrade per l’Italia S.p.A. (ASPI), a private company responsible for the management and maintenance of Italy’s motorway network. Both MIT and ASPI follow a risk-based approach to prioritize inspections and maintenance efforts on bridges, however, some differences and variations characterised the approaches. While the specifics may differ, the overarching goal of ensuring bridge safety and preventing catastrophic failures remains consistent. This paper aims to provide a comparative analysis of different guidelines for the risk classification, safety assessment, and monitoring of existing bridges, considering several A16 viaducts as case-studies, made of prestressed concrete, highlighting the key similarities and differences among them. The comparative analysis reveals important insight aimed to continue refining and adapting these guidelines and manuals to best serve the safety of existing bridges and the communities they support.
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