PSI - Issue 84

Rosario Montuori et al. / Procedia Structural Integrity 84 (2026) 967–974

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The following figure provides a synthetic representation of the methodology described above, which is better explained in Fig. 1. 3.1. Phase 1: Inventory and census In this phase, a database of all bridges and viaducts belonging to the road network managed by the Road Authority is created. In this context, it is essential to collect all the information that will constitute the “identity card” of each bridge structure, including any available design documentation, approval documents, or records related to subsequent interventions or investigations. This allows the Road Authority not only to maintain an up-to-date database of the structures under management, but also to facilitate the subsequent evaluation phases of the methodology. In conjunction with this phase, a specific Inventory Form must be compiled, collecting all the relevant information. In particular: • Location : road name, kilometre reference, municipality or municipalities (in the case where the structure is located at the boundary between two different administrative jurisdictions), structure name, crossed obstacle; • Year/period of construction (to be estimated if reliable data are not available); • Traffic data : Average Daily Traffic (ADT) – Public Transport Traffic; • Alternative routes ; • Geometric characteristics : total length, total width, carriageway width, number of lanes, vertical clearance over the crossed obstacle; • Structural characteristics : structural scheme, construction materials, number of spans, span lengths, identification and numbering of structural elements (abutments, piers, girders, cross-beams, deck slabs, arches, expansion joints, arch piers, bearings); • Any other relevant information . 3.2. Phase 2: Inspection In this phase, visual inspections of all structural elements of the bridge structure are carried out by compiling specific Inspection Forms, while also collecting photographs and objective data on the detected damage. A first crucial step, especially during the initial inspection, is the inventory and numbering of structural elements. Each bridge is subdivided into specific elements (such as girders, piers, abutments, expansion joints, deck slabs, arch piers), each of which is associated with a dedicated Inspection Form, which varies depending on the material of the element. These forms constitute a systematic list of the defects that may occur in the element, each of which is associated with a weight G (also referred to as damage gravity), ranging from 1 to 5 (1 = low damage gravity, 5 = high damage gravity). Each defect is also associated with a Defect Form, which supports the inspector in evaluating the severity of the defect through a score (0, 0.25, 0.5, 0.75, 1), also referred to as damage severity (S). The Defect Form also provides indications regarding potential causes and the corrective interventions required for that specific defect. The inspector must also determine whether the listed defects are applicable to the inspected element and whether they are actually inspectable. For example, the defect “Unsealed anchorage heads” can only be assessed if the considered element is a prestressed reinforced concrete (PRC) girder; otherwise, the defect is classified as Not Applicable. If the girder is indeed prestressed reinforced concrete but the anchorage heads are not visible, the defect is classified as Not Observable. Furthermore, the inspector must assess defects exclusively on the visible portion of the element, corresponding to the part that can actually be inspected. This parameter, reported in the Inspection Form, is referred to as the Observable Percentage. Visual inspection is an operation that must be performed rigorously and at regular intervals on all elements of each bridge structure. It allows the identification, and subsequently the elimination, of the causes of deterioration and their related consequences, as well as the definition of ordinary and extraordinary maintenance operations. It represents both the starting point and the most important activity for those responsible for infrastructure management, whose objectives are the safety of structures, the safety of traffic, and the efficient use of financial resources.