PSI - Issue 84

Matteo Vozzi et al. / Procedia Structural Integrity 84 (2026) 425–432

429

The APT method was developed as a decision-making tool to prioritize interventions across the entire bridge portfolio managed by the authority. The stock includes a large number of structures with variable characteristics and conditions. In this situation, the calculation of the bridge reliability index must be performed based on knowledge - namely the ∙ parameters - derived from simplified analyses and visual inspection of the structure that require relatively limited effort and can therefore be applied on a large scale. Conversely, the SINA method was conceived as an in-depth assessment tool to be used once the overall maintenance strategy for each bridge has been defined. In this case the quantification of an and of their variability is possible based on the results of a detailed structural analysis. This approach can be therefore applied to a much more limited and homogeneous set of structures, for which a higher level of knowledge is available, compared to the entire bridge inventory. Another difference lies in the fact that the method based on postponement costs estimates the probability of failure of the most highly stressed element, i.e., the one characterized by the lowest resistance-to-effect ratio ⁄ . The second approach, on the other hand, evaluates the probability of failure based on the predictive analysis of the future status of all defects detected on the structure and therefore considers, other than the actual state of conservation of the bridge, also its evolution over time. Finally, another element that differentiates the two methods concerns the damage resulting from structural collapse. The second method focuses on the protection of human life, which is certainly the most important type of damage, whereas the first also considers economic losses, which become significant when a structure is of limited size and the probability that a collapse could cause casualties is very remote. 5. Case studies The intervention prioritization methods described in the previous sections were applied to a bridge network consisting of 13 structures, whose main characteristics are reported in Errore. L'origine riferimento non è stata trovata.. In particular, the bridges with codes from P3 to P10 and P13 belong to a motorway, while the remaining ones are located on extra-urban provincial roads. Table 1 Main characteristics of the analyzed structures Code Type Number of spans Maximum span [m] Structural scheme Material Design code Damage Index D

1 1 1 1 1 1 1 1 1

P1 P2 P3 P4 P5 P6 P7 P8 P9

Overpass Overpass Underpass Underpass Underpass Underpass Underpass Underpass Overpass Overpass

3 3 1 1 1 1 1 1 1 1 5 3 7

27 27

Simply supported Simply supported

PSC PSC

1962 1962 1962 1962 1962 1962 1962 1962 1962 1962 1933 1962 1952

6 6 4 6 6 5

Fixed slab Fixed slab Fixed slab Fixed slab Fixed slab Fixed slab

RC RC RC RC RC RC

0,99

15 15 31 31 34

Simply supported Simply supported Continuous girder Simply supported Half joint beams

PSC PSC

P10 P11 P12 P13

0,8

Viaduct Viaduct Viaduct

RC

0,92 0,92

PSC

RC

6. Analysis Figure 1 reports the results of the application of the SINA approach based on the cost of postponing interventions by one year. These one-year deferral costs reported in the figure values do not represent the actual costs of postponing the intervention, but rather conventional values, used exclusively for comparison among the different structures. A high deferral cost is indicative of a greater priority of intervention. From the analysis, it emerges that the structures for which a greater priority of intervention is identified are those belonging to the motorway network, with the sole