PSI - Issue 84

634 Vittorio Palma et al. / Procedia Structural Integrity 84 (2026) 630–637 Within , the defectiveness level retains a hierarchical role, while hazard and exposure act as subsequent criteria. The comparison between two bridges and is therefore defined through a lexicographic ordering: ≺ ⇔ { < , or = and ≺ lex . (7) where ≺ lex denotes a sequential comparison according to a predefined and monotonic order (e.g. higher , then higher , then higher ). Also in this case, the formalisation makes explicit the non-compensative nature of the procedure, since critical conditions and higher defectiveness levels govern the main priority class, and its monotonicity with respect to the guiding indicators, while preserving a refined and replicable within-class ranking suitable for large stocks of assets. 5. Methodology for the programming of local interventions aimed at restoring or improving durability The methodology developed by SINA S.p.A. for prioritising restoration and durability improvement works proposes a unified classification of structures based on the integration of three fundamental parameters: structural defects, durability and user safety. The latter aspect specifically concerns the risk of detachment or crumbling of concrete cortical elements or prefabricated accessory components which, while not necessarily compromising the primary stability of the structure, represent a danger to the safety of people and property in the areas below. In order to respond to the need for managers to clearly distinguish between preventive maintenance and emergency interventions, the method has recently evolved into a dual classification system. This approach divides priorities into two distinct streams: the first ranks works according to their state of structural deterioration and durability requirements (local repairs and renovations); the second, on the other hand, establishes a hierarchy of urgency based The methodology involves considering only viaducts that have not yet undergone a complete safety assessment and structures already classified as Operativo (Operational) or Adeguato (Adequate) following Level 4 analyses (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020). The following are excluded from the assessment: structures classified as Transitabile (Passable) (intended for complex structural improvement or renovation works), structures requiring specialized analytical investigations (the results of which could necessitate the design of interventions affecting the superstructure), structures where interventions are already underway or planned, structures with High Priority Class for which the final result of the safety verification is not yet available, and prestressed concrete (P.C.) structures for which special inspections of post-tensioned cables have yet to be performed (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020). The assignment of the maximum rating is reserved for structures exhibiting a High (Priority 1) or Medium-High (Priority 2) level of structural defectiveness, consistent with the classifications provided by the prioritization method for safety assessments illustrated in the previous chapter (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020). In the presence of minor defect levels (Medium, Medium Low or Low), where there are no issues compromising the overall structural functioning of the work, prioritisation is refined by considering, in addition to Structural Defectiveness, the following additional risk and degradation factors: • user safety : this parameter, consistent with the definition provided above, assesses the risk arising from cortical degradation and the potential fall of fragments. At this stage, prioritisation is refined through the analytical quantification of reports collected by technical inspectors during on-site inspection campaigns. These operators are responsible for accurately recording any surface defects, including the aforementioned detachments or crumbling, which may pose a danger to the areas below, whether they be roads, squares or private properties (Ministero delle Infrastrutture e dei Trasporti (MIT) 2020); • durability : i.e. malfunctions in the platform water disposal system, which could cause an acceleration of the normal degradation of materials and therefore compromise the durability of the structure. For each project, elements presenting defects such as Scossalina permeabile o assente (permeable or absent flashing), Convogliamento acque assente (absent water conveyance), Pozzetti intasati (clogged drains), Scarichi corti exclusively on critical issues related to user safety and the risk of falling materials. 5.1 Integrated classification of structural defects, durability, and user Safety