PSI - Issue 84

L. Zoccolini et al. / Procedia Structural Integrity 84 (2026) 167–174

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Table 2. Summary of the mean hazard risk level scoring approach

Hazard Score 6

Hazards

Hazard risk level

Isostatic Spans

Continuous Beam spans

Very High

- -

- -

High

5 4 3 2 1

Medium

33

33

Low

6

6

Very low Negligible

- -

- -

Mean hazard risk level score H

3.85

3.85

Since the set of hazards is assumed to be identical for all types of spans in the analyzed set, the mean hazard risk level score is the same for all spans considered. Across the entire study sample, the mean hazard risk level score is 3.85, regardless of span structural type. 5. Conclusions This study analyzed and compared the two prioritization methods provided by CS465, the risk rating and the mean hazard risk level scoring approach, applying them to a representative case study of an extensive, recently constructed infrastructure. The analysis of the risk rating method showed that the year of construction has a particularly significant influence on the final score. Indeed, in a set of spans built in the same period, as in the case study analyzed, the prioritization capacity of the approach is reduced because the year-of-construction component does not contribute. Furthermore, the process has an intrinsic saturation effect, linked to the upper limit of the condition factor and the vulnerable details and materials factor, which prevents distinguishing between different levels of degradation once the maximum allowed value has been reached. A further limitation of the risk rating approach is its binary treatment of hazards: it only allows the presence or absence of a hazard to be identified. It does not provide tools to describe its extent or severity. As a result, localized defects and widespread degradation phenomena are considered equally, potentially leading to a loss of information relevant to prioritization. The approach based on mean hazard risk level scoring, on the other hand, has conceptually different characteristics. By combining hazard likelihood and consequences, this formulation enables a more direct integration of hazard severity. Because of this feature, the approach is more sensitive to the kind and severity of individual hazards. However, the applicability of this method is closely linked to the availability and quality of inspection data. In the absence of accurate information at the individual span level, as in the case study considered, the set of hazards is necessarily uniform across the entire infrastructure, resulting in a loss of prioritization capacity between different spans. Furthermore, it has been observed that the presence of hazards classified as negligible can have a counterintuitive effect on prioritization. Although these hazards are of little relevance, they still contribute to the average score by assigning a hazard score of 1, lowering the final value compared to the case where the risk is not considered at all. This suggests the need for critical reflection on the inclusion of negligible risks in the calculation of the synthetic indicator. Overall, the results confirm the complementary nature of the two methods proposed by CS 465. The risk rating approach lends itself to preliminary assessment and network management, providing an overview of the risk profile. In contrast, the mean hazard risk level scoring approach is more suitable for supporting operational decisions when detailed inspection data is available. However, both approaches have limitations that must be carefully considered in practical application. The study, therefore, highlights the need for a careful, informed selection of the prioritization method, considering the specific management objectives and the availability and quality of the data. Furthermore, it underscores the importance of complementing regulatory-based tools with detailed inspection information and engineering judgment to achieve an effective, reliable, and robust management of existing infrastructure.