PSI - Issue 62

Elena Elettore et al. / Procedia Structural Integrity 62 (2024) 113–120 Elettore et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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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. © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of Scientific Board Members Keywords: Existing bridges, Comparative analysis, Italian guidelines, Monitoring, Inspections, A16 viaducts 1. Introduction The functionality and safety of crucial transportation infrastructures like bridges are essential for contemporary societies. Aggressive environmental conditions and increasing traffic volume can cause significant deterioration to many bridges (Pregnolato et al. 2019). Therefore, timely maintenance measures and adequate frequent maintenance interventions are of paramount importance to ensure a satisfactory performance of transportation networks over their life spans (Santarsiero et al. 2021). The methodologies for safety assessment of bridges 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 regular visual inspections to advanced sensor networks, structural health monitoring and non-destructive testing methods. The combination of these methodologies allows a comprehensive assessment of the safety of existing bridges and avoids invasive and expensive rehabilitation works (Avossa et al. 2018), inducing high impact on traffic management and safety. Italy is a nation renowned for its intricate network of waterways, featuring historic viaducts, bridges, and tunnels that are vital components for transportation. The deterioration of bridges due to corrosion, age, lack of maintenance or environmental factors can cause significant risks to the safety, welfare, and economy of contemporary societies (Santarsiero et al. 2021, Crutone et al. 2023). The failure of the Polcevera Viaduct (Calvi et al. 2019) is an iconic example, which killed 43 people the 14 th of August 2018 in Genova (Northern Italy) and forced motorway traffic to take an urban diversion with consequent congestions. After this event, the Superior Council of Public Works, as part of the Italian Ministry of Infrastructure and Transport (MIT) developed specific Guidelines on risk classification and management, safety assessment and the monitoring of existing bridges (LG20). The Guidelines were approved as a technical code through the Ministry of Infrastructure Decree n. 578 (17 December 2020). These guidelines aimed to define and standardize the criteria for monitoring, assessing structural safety, and classifying the risk of existing bridges through a multi-risk approach. The Guidelines LG20 can be considered a specialized standard, in agreement with the provisions of the Standards for Construction (NTC 2018) and Application Circular (Circolare 2019), conceived to consider the bridge vulnerability, the environmental hazards ( e.g., seismic, landslide, flooding), and the exposure ( e.g., traffic loads, etc.) to evaluate the infrastructural risk. The guidelines aim at a quick identification of the road infrastructure to prioritize for intervention to be performed, thus ensuring savings in terms of human, economic, and time resources. On the other hand, Italian bridges are owned and managed by various local and national bodies that use in-house management systems with different levels of complexity. Amongst others, Autostrade per l'Italia S.p.A. (ASPI) is the Italian highway main management corporation, responsible for most of the management and maintenance of Italy's motorway network. In 2020 ASPI released the Surveillance Manual for Major Assets, Visual Inspection (ASPI,2020), a multidisciplinary inspection manual for the inspection, identification of the defects and the state of deterioration recognition with a quantified analysis of the deterioration effects. Both MIT guideline and ASPI manual 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 © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Scientific Board Members