PSI - Issue 62

Manuel D’Angelo et al. / Procedia Structural Integrity 62 (2024) 9–15 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

10 2

1. Introduction Bridges play a crucial role in modern infrastructure and society, since they guarantee the connectivity of people, goods, and services across communities, regions, and even countries. In the last years, a renovate concern for bridge management and safety has risen from bridge owners, stakeholders, and authorities. In fact, the majority of existing infrastructures worldwide are experiencing deterioration caused by factors such as aging, environmental stressors, human-made hazards, and natural events like floods, earthquakes and hurricanes (Frangopol 2017, Deng 2016). As a result, many countries have developed procedures to evaluate bridge risk within the infrastructural network (Biondini 2022, Cerema 2019). In Italy, in 2020, the Italian Ministry of Sustainable Infrastructures and Mobility published the guidelines for the classification, risk management, safety evaluation and monitoring of existing bridges, from here-on called the Guidelines. The primary objective was to establish a comprehensive and well-organized management system for Italian bridges, ensuring equal adoption by all road operators. Some recent works in the literature analysed and discussed the first results obtained by the implementation of the Guidelines on some case studies (Natali 2023, Bencivenga 2023, Buttarazzi 2023). Specifically, the focus in this earlier phase has been towards bridges managed by major owners (highways, state roads, etc.). Besides the highways, the Italian management road system is rather hierarchical, in which the small local and urban roads are managed by Municipalities, and the country roads by Provinces, Regions, and the State, depending on their extension. The infrastructural system at the local level can be quite complex, or, in turn, quite simple, depending on the geographic location, the hydrogeological context, and the urban development. Thus, the characteristic and even the number of bridges at the local level is unknown in this early phase. Within this context the present paper shows and discusses the application of the Guidelines to a sample of bridges owned by municipalities at the local level and investigated by the authors. Paragraph 2 shortly resumes the methodology proposed by the Guidelines. Paragraph 3 shows the main characteristics of the sample from a structural point of view, while Paragraph 4 discussed the state of conservation of the sample according to the parameters defined in the Guidelines. Finally, Paragraph 5 shows and discussed the result in terms of Warning Class, the risk indicator parameter defined in the Guidelines. 2. Multi-level and mutli-risk approach of the Italian Guidelines The comprehensive approach outlined in the Italian Guidelines involves establishing “Warning Classes” (WC) for various risk sources (such as structural-foundational, seismic, hydraulic, and landslide) through predefined logical sequences. The WC is defined on five levels: high, medium-high, medium, medium-low, and low. Specifically, the four Warning Class, identified in the Level 2 of the procedure, generate together the Overall Warning Class (OWC), a global indicator of the risk connected to the structure. For each risk source, this class is calculated as the convolution of three risk components: hazard, vulnerability, and exposure. The determination of each WC relies on the information gathered through the census activity (level 0) and acquired during on-site inspections (level 1), encompassing both typological and detailed data. For a detailed dissertation of the Italian Guidelines (GL), the reader may refer to Natali et. Al. 3. Description of the sample For the Level 0 activities, 342 bridges were censed, managed by 45 owners (43 Municipalities, 1 Province, and 1 Region). The sample of bridges covers the central-northern part of Italy, not homogenously distributed in the territory (Fig. 1). The bridges locate in various hydrological contexts, from flat plains to mountain environment. Therefore, hydraulic and landslides risk is relevant for a portion of the sample.