PSI - Issue 64

Anna Sanseverino et al. / Procedia Structural Integrity 64 (2024) 1271–1278 A. Sanseverino et al. / Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction To date, most of Italy's infrastructure is often neglected and lacks regular maintenance. Thus, it seems that only catastrophic events draw attention and prompt legislative changes. Most of the bridges and viaducts in Italy were built after the Second World War; indeed, according to a 2019 survey (Gabanelli and Pasqualetto, 2019) and, no less than 52% of these were built before 1980, and only 15% were less than 18 years old. The issue of securing ageing infrastructure in Italy is usually addressed using a case-by-case scan-to-BIM approach (Banfi et al., 2017). This involves collecting primary data, typically through advanced 3D digital survey techniques like “Terrestrial Laser Scanning” and “Unmanned Aerial Systems”, which facilitate in-situ inspections, reducing time, cost, and risk for the operators. However, even if using these digital models for structural health monitoring (SHM) offers significant advantages over traditional methods, there are still challenges in adopting the proper tools for managing complex infrastructure efficiently (Previtali et al., 2022). 1.1. Italian applications on bridge digitisation and LG20 implementation The benchmarks within the Italian regulation framework form maintenance and inspection of road artwork are: “Guidelines for the Risk Classification and Management, Safety Assessment and Monitoring of Existing Bridges – LG20” (DM 578/2020) – which defined the modalities for the implementation, on an experimental basis, for a period not exceeding 24 months, of a monitoring system for road and highway infrastructures managed by ANAS S.p.A or by highway contractors – and the development of the “Information Archive of Public Structures - AINOP” (DM 430/2019; DM 578/2020 - All.A). Namely, the AINOP database, introduced by the Italian Ministry of Transport (MIT) in the aftermath of the collapse of the Polcevera viaduct in Genoa (DL 109/2018), upon “feeding”, generates a unique identification code of the individual structure “IOP” (“Identificativo Opera Pubblica”) (see Fig. 3). According to the LG20 (DM 578/2020), Public Administrations (PAs) must define a Bridge Management System (BMS) for the census and risk classification, safety verification, surveillance, and monitoring of existing bridges and viaducts. Additionally, the LG20 propose a risk-based procedure for risk management of existing bridges, with six progressive levels of in-depth knowledge of the artwork and the infrastructure network according to the criticality level of the artwork itself (Salvatore, 2019) listed as follows: • Level 0 (L0 – Census of the infrastructures) 1 • Level 1 (L1 – Visual inspections and defect forms) 2 • Level 2 (L2 – Analysis of detected risks and classification on a territorial scale) 3 • Level 3 (L3 – Preliminary assessment of the structure) • Level 4 (L4 – Accurate safety assessment) • Level 5 (L5 – Infrastructure network resilience) Afterwards, the DM 204/2022 provided for the extension of the adoption of the same Guidelines also to the "local roads", and the extension of the trial period from 24 to 48 months 4 . The regulation requirements for the definition of an effective BMS, capable of assuring the cooperation between different stakeholder and work teams, can be achieved via BrIM modelling (Costin et al., 2018), i.e., the application of the Building Information Modelling (BIM) approach to bridges (Xu and Turkan, 2020). Following the introduction of LG20 guidelines, discussions have highlighted the need to use Structural Health Monitoring (SHM) with harmonized standards based on the latest research (De Matteis et al., 2022; Ormando et al., 2022; Polania et al., 2022). Furthermore, LG20 applications have focused exclusively on a case-by-case implementation and manual recording of defectiveness parameters within Historic Building Information Modelling (HBIM) in order to 1 “Level 0 Bridge Census Form – Annex A of the LG20” (DM 578/2020 - All.A) provides essential information for subsequent levels and aligns with Ministerial Decree No. 430/2019 for the setting up of the AINOP. 2 For Level 1, surveys include comprehensive photographic, geometric, and preservation state assessments of the structure that are documented in specific forms found in “Annex B of the LG20” (DM 578/2020 - All.B) and “defect forms”(DM 578/2020 - All.C). These forms are tailored to different bridge elements and materials. 3 Level 2 involves defining the "Attention Class" (CdA) to estimate the risk for existing bridges through three steps: identifying structural characteristics, combining Hazard, Vulnerability, and Exposure factors, and determining a unit parameter from a multi-hazard analysis. This results in an overall CdA ranging from High to Low, indicating the need for monitoring or periodic inspections. 4 Deadlines for completing these levels are: ANAS S.p.A. – Census (L0) by December 2022, Attention Classes (L2) by December 2023; highway contractors – L2 by June 2023; regions, provinces, and metropolitan cities – L0 by December 2023, L2 by June 2025; municipalities: L0 by June 2024, L2 by 2026.