PSI - Issue 84

Chiara Galatà et al. / Procedia Structural Integrity 84 (2026) 1–8

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enable a cross–framework reinterpretation under the US (NBIS/BIRM+MBE; Caltrans), French (CEREMA/ITSEOA F32) and Dutch (RWS RBK) approaches. 3.2. MIT–2020 baseline The MIT–2020 workflow was adopted as the primary reference point. For each bridge, harmonised Level 1 defect sheets fed the Level 2 risk model to obtain Structural and Seismic AC (hazard–vulnerability–exposure). Vulnerability used primary parameters–defectiveness, structural typology/span, materials, configuration incl. PT layout–and secondary ones (degradation rate, design era/code, past works). Defectiveness, derived from mapped distress (cracking, spalling/delamination, joint leakage, tendon/anchor anomalies), was graded on a common ordinal scale and typically dominated vulnerability. Hazard combined traffic and environmental aggressiveness; exposure captured consequences (ADT, detour, socio–economic relevance). PT red flags (grout voids, anchor–zone distress, low–point moisture) triggered special inspections (endoscopy; GPR/IE/UT; electrochemical; selective sampling/strand checks); results updated vulnerability and, when needed, escalated to Level 4 checks. For the seismic AC, hazard came from PGA/site class; exposure mirrored the structural case; vulnerability reflected regularity/redundancy, bearings/restraints, joints/shear keys, substructure/foundations, and known code gaps–significant discontinuities prompted targeted verifications and possible Level 4. In the next section we report a summary table listing all 20 bridges with their Structural and Seismic Attention Classes (AC) (Low/Medium/High), together with the status of any special inspections and Level 4 escalation flags. This table provides the benchmark against which each bridge is then re–interpreted under the other frameworks (USA– NBIS/BIRM/MBE and Caltrans; France–CEREMA F32; Netherlands–RBK), enabling a direct cross–normative comparison. 3.3. MIT–2020 classification results Method notes (ANSFISA, 2022). Structural and Seismic defectiveness is derived from Level 1 sheets and classified into five levels (Tab. 4.14), with explicit critical elements (bearings, pile ends) and critical conditions (e.g., kinematic mechanisms). Elements are grouped into Superstructure (spans) and Substructure (piers/abutments/foundations; bearings tied to the pier). Aggregation rules: (i) at span/substructure–group level use an envelope–if any High/Medium–High element exists, the group takes that level; (ii) otherwise apply a percentage rule to assign Medium / Medium–Low / Low (typical 50% threshold for “Medium”). The bridge–level defectiveness is the maximum across spans and substructure. Definitions of intensity/extent follow the structural–foundational instructions, to which the seismic chapter is aligned. Table 2 reports the primary inputs and the resulting Structural/Seismic AC computed as per the Method note (ANSFISA, 2022; MIT, 2020). Legend. S = structural; E = seismic; N = number of spans; DEF–S/DEF–E = defectiveness level; VUL–S/VUL–E = vulnerability; AC–S/AC–E = Attention Class (L/M/M–H/H). Material is PTPC for the whole cohort. Defectiveness is the only subjective primary; with material fixed, High vulnerability generally implies High or Medium–High AC under MIT–2020.

Table 2. Determination of Structural and Seismic Attention Classes (AC) for the case–study bridges under MIT–2020

Param/Bridge

N

DEF–S

DEF–E

VUL–S

VUL–E

AC–S

AC–E M–H M–H M–H M–H M–H M–H

B01 B02 B03 B04 B05 B06

23

M M

M M

M–H M–H

M–H M–H M–H M–H M–H

H

5 9 6 9 8

M–H

M–L

M–L

M

M

M

M

M–H

M–H

M–L

M–L

M

M M

L

L

M–L

M