PSI - Issue 84

Alessandro Pucci et al. / Procedia Structural Integrity 84 (2026) 433–440

436

element, and (iii) its spatial positioning (accounting also for any location within predefined critical zones of the element, if present). Therefore, for each defect category, unique values of the extent and intensity indices (k 1 and k 2 ) are computed at the element scale. Two distinct indices can be computed to characterize the risk associated with a single structural element: • the defectiveness level L d , which— similarly to the approach outlined in the Italian Guidelines for bridge inspection and assessment (DM204/2022) —can be determined based on the highest severity G of the defects found, the corresponding extent (k 1 ) and intensity (k 2 ) overall values, and the number of defect categories identified (relative to the total number of categories expected for that element type in the predefined defect list) during the degradation analysis phase. • the priority score I d , which can generally be calculated as the ratio between the measured damage and the maximum damage that the element could potentially sustain. = _ _ (2) where the maximum damage is defined based on a predefined list of defect categories that can realistically be found on a specific element. The value of the priority index I d may be influenced by the defectiveness level L d through the introduction of a multiplier α, which scales the value of the I d index as a function of L d : = ( ) ⋅ (3) The element level explicitly accounts for defect interaction mechanisms, including spatial distribution, concentration, and localization within critical regions of the element. Consequently, the analysis requires detailed knowledge of defect geometry, element geometry, and their mutual spatial relationships. The element-level assessment therefore represents a transition from isolated defect characterization to a category based evaluation of degradation mechanisms acting on structural components. Then, the workflow proceeds to the overall structural risk analysis, which involves grouping elements (along with their respective assessments) into coherent structural groups in order to determine the bridge's priority score and corresponding defectiveness level. 2.2. Maintenance phase The maintenance phase utilizes the outcomes of the previously described inspection—specifically, the geometric distribution of defects projected onto the three-dimensional structure and assigned to the various BIM elements—to design restoration interventions aimed at addressing the degradation conditions identified during the analysis. With the precise spatial distribution of defects available—that is, their geometry and exact positioning on the structural elements (Fig. 2) —it is possible to perform automatic clustering of defects based on their mutual distances and on the type of repair intervention required for each defect category.