PSI - Issue 62

Anna Rosa Tilocca et al. / Procedia Structural Integrity 62 (2024) 1043–1050 A.R. Tilocca et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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5.3. Geotechnical and hydraulic attention class indexes CDA g - CDA h The railway bridge in question is not it affected by landslides, as evident in the IFFI landslide cartography (Figure 10a). The IFFI Project (Inventory of Landslide Phenomena in Italy), created by ISPRA and the Regions and Autonomous Provinces, provides a detailed picture of the distribution of landslide phenomena on Italian territory. To date, the inventory has recorded over 620,000 landslides on the national territory. The inventory represents a basic cognitive tool for the assessment of the landslide hazard of the Hydrogeological Management Plans (PAI), for the programming and preliminary design of soil defense and infrastructure network interventions and finally for the drafting of the emergency plans of civil protection. The probability of a landslide event involving our case study infrastructure can therefore be considered negligible and the CDA g index is low . Concerning also the hydraulic risk, consulting the idroGEO website of ISPRA, it is possible to understand that hazards are not present (also any rivers are under or nearly the railway bridge) and the risk level is low . (see Figure 10b).

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b)

Figure 10. a) IFFI map for railway bridge; b) idroGEO maps for railway bridge.

6. Attention class index for the railway bridge CDA DEF The separate analysis of the structural and foundational CDA sf and seismic CDA s , beyond the CDA h linked to hydraulic risk and the CDA g linked to landslide risk (preliminarily combined between them) must be accompanied by the evaluation of a unitary parameter which allows to arrive at a synthetic definitive index CDA DEF . This last parameter indicates the overall Attention Class of the bridge and is the result of the combination of the different CDAs associated with the four types of risk, conducted, once again, according to an approach based on classes and logical operators. The definitive CDA DEF is classified, similarly to what was seen for the individual CDA, into low , medium-low , medium , medium-high and high . In our case for a railway bridge, considering also all the assumptions described above, the definitive attention class index CDA DEF is medium-high (see Table 3).

Table 3. Definitive attention class index CDA DEF

7. Conclusions In the present paper a bridge case study is treated in order to apply the multi-level multi-risk approach suggested by the Italian Guideline. All passages are descripted in details for check principally the flowcharts method and analyze the principal and secondary parameters that are involved. Considering also the fact that the infrastructure in the present case study is a railway bridge, is necessary to understand how its particular defects listed only in a specific design and maintenance manual (RFI, 31/12/2020) are taken into account from the Italian Guideline here descripted. The multi-level multi-risk method do not represent, in the level 1, so