PSI - Issue 84

Vittorio Palma et al. / Procedia Structural Integrity 84 (2026) 630–637

631

Keywords: Management of existing infrastructure, Prioritisation methodology, Safety assessment, Special Inspection, Repair interventions Main text

1. Introduction The management of existing bridge networks requires the programming of inspections, safety assessments, and maintenance interventions under economic and operational constraints, often in the presence of heterogeneous and incomplete information. Within this context, prioritisation represents the key decision-making mechanism that allows limited resources to be systematically directed toward the most critical assets, while preserving acceptable safety levels and continuity of service at the network scale. In Italy, the regulatory and methodological reference framework is provided by the Guidelines for the classification and management of risk, safety assessment, and monitoring of existing bridges (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020). The Guidelines define a multi-level assessment process and conceptualise risk through the interaction of vulnerability, hazard, and exposure. However, their application at a large-network scale requires operational procedures capable of explicitly and reproducibly translating inspection outcomes and classification results into actionable priorities for different phases of the management process, namely: special inspections, detailed safety assessments (Level 4), and local interventions. Several approaches have been proposed in the literature to address prioritisation at the network level. Bridge Management Systems (BMS) provide integrated frameworks for data management and decision support, often oriented toward long-term optimisation and budget allocation (Yang 2013; Penadés-Plà et al. 2016; Salvatore e others 2024). In parallel, Multi-Criteria Decision Making (MCDM) methods, such as AHP and TOPSIS, are widely adopted to combine condition indicators with traffic and exposure factors, particularly when information is qualitative or incomplete (Penadés-Plà et al. 2016; Yang 2013). Risk-based and optimisation-oriented models further extend this perspective by incorporating probabilities of damage or failure and their consequences, including impacts on network functionality and resilience (Salvatore e others 2024; Casas e Matos 2019; Capacci e Biondini 2021). Despite the maturity of these approaches, an operational gap remains when the objective is to adopt a prioritisation tool fully aligned with the workflow prescribed by the Guidelines and applicable consistently at a large scale. Many MCDM formulations are compensative and strongly dependent on weight calibration, while fully probabilistic approaches require levels of information and modelling effort that are rarely available during the early stages of network-level asset management (Verzobio et al. 2022; Capacci e Biondini 2021). In addition, for specific bridge typologies, such as post-tensioned prestressed concrete bridges, the Guidelines prescribe dedicated special inspections prior to detailed safety assessments, requiring the definition of specific and coherent programming criteria (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020). The present work addresses this need by formalising a set of prioritisation methodologies developed within operational applications by the FABRE University Consortium, ASTM S.p.A., and SINA S.p.A. The proposed framework supports the network-level programming of: (i) special inspections for post-tensioned prestressed concrete bridges (Mazzatura, Caprili, et al. 2023; Mazzatura, Natali, et al. 2023; Mazzatura, Salvatore, et al. 2023), (ii) safety assessments (Level 4) (Celati et al. 2025), and (iii) local interventions aimed at restoring or improving durability. Consistently with the Guidelines, the procedures are formulated as rule-based and predominantly non-compensative approaches, relying on ordinal variables, discrete priority classes, and within-class rankings to ensure transparency, traceability, and replicability of the decision-making process. The paper is organised as follows: Section 2 presents the common decision framework adopted for the three modules; Sections 3–5 describe the methodologies for special inspections, safety assessments, and local interventions, respectively; Section 6 discusses implications, limitations, and applicability; and Section 7 summarises the main conclusions and outlines future developments. 2. Problem formulation and decision framework The methodologies presented in this work are conceived as a decision-support framework for the network-level programming of activities prescribed by the Guidelines for existing bridges, under conditions of limited resources and heterogeneous information. Consistently with the Guidelines, the available knowledge is synthesised through