PSI - Issue 62

Alessandro Lipari et al. / Procedia Structural Integrity 62 (2024) 24–31 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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overall CA. This is often the case, as the structural CA bears the highest influence on the overall CA and the other risks do not vary the overall CA as much (Santarsiero et al., 2021). Moreover, when the structural CA is H, the overall CA is H, regardless of the other risk classes. The overall CA determines which further actions to take, according to Fig. 1.

Level 0

Geolocation / Census

Level 1

Visual Inspections / Defect Forms

Post-tensioned cable bridges and/or flood, erosion, landslides or high hydrogeological risk

Special Inspections

Yes

OK

Required a safety assessment according to NTC and / or high intrinsic "fragility"

Yes

Level 4

No

Simplified Assessment of Risks (Structural-Foundation, Seismic, Landslides, Hydraulic)

Level 2

CA Medium - High

CA Low

CA High

CA Medium

CA Medium - Low

Periodic Inspections

Period./Addit. Inspections and Monitoring

Periodic or Additional Inspections and Monitoring

Period./Addit. Inspections

Preliminary assessment

Preliminary assessment

Level 3

Accurate Assessment

Level 4

OK

• Operation • Transitability: restrict. use • Transitability: limit. loads

Maintenance Interventions

Update Class of Attention

Retrofit Intervention

Fig. 1. Multi-level approach according to Italian guidelines.

As can be seen, for CA’s L or ML it is sufficient to continue with the periodic inspections. For higher CA’s, an assessment L3 (CA M or MH) or L4 (CA H) must be carried out; besides periodic inspections, additional inspections and/or monitoring should be carried out if appropriate. Special inspections are required for post tensioned PSC bridges or landslide/flooding-prone bridges. The parameters required for determining the structural CA are reported in Table 1, highlighting the values used in the two case studies presented in Section 3. Information is collected from visual inspections (L1) and census (L0). Note that the L0 content is mostly retrieved from record information or needs to be provided by the road managers, e.g., traffic data, alternative routes; however, such information may not be comprehensive enough.

Table 1. Input parameters for determining the structural risk. Class Parameter Number of entry option

Entries

Class A to E (current design load; restriction to 44, 26, 8 or 3.5 t)

Hazard

Permitted load

5 3 5 7

≤ 300 (L) , 301-699 (M) , ≥ 700 (H) HGV/day/lane

Average Daily Truck Traffic

L, ML, M, MH, H

Vulnerability

Level of deterioration

Structural scheme

Simply-supported girders, continuous girders/frame, solid spandrel arch, open-spandrel arch, cantilevered bridge with suspended beams , simply-supported slab, clamped slab.

≤ 5, 5 -15, 15-25, ≥ 25 m

Maximum span length

4 7 2

RC, PSC , Steel, Iron, Timber, Masonry, Composite

Material

≤ 3, > 3

Number of spans