PSI - Issue 62

Stefano Grimaz et al. / Procedia Structural Integrity 62 (2024) 161–168 S. Grimaz et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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• Secondary EC – Supported elements transmitting/transferring forces to primary elements. May provide protection/cover for primary EC or constitute the structure of apparatus/systems. For bridges, common examples are secondary beams, elements of water disposal systems, and road furniture elements (curbstones, sidewalks, guardrails, lighting poles, barriers, etc.). Once ECs are inspected, identified, and classified, the warning color codes are assigned to various districts following the VISIT algorithms, to generate the asset’s characterization chart. Next, technical triage criteria are applied to assign a surveillance protocol code to the overall bridge. Surveillance protocols differ based on the nature and magnitude of the identified deficits, as defined in Grimaz et al. (2023). Bridge characterization charts take a “diamond” form, as illustrated in Fig. 1. These charts provide an overview of the inspection evaluations and visually characterize deviation levels for each district. This serves as a technical triage record to summarize asset situation for treatment purposes.

Fig. 1. Left: bridge characterization diamond chart. The chart permits to summarize the safety deficits identified in the various districts through a warning color code. Right: example of “ Constitutive Elements ” for the various core and completion districts. 3. The visual inspection of bridges According to the VISIT methodology, ANSFISA surveillance inspections of bridges require analyzing the core and completion districts through finalized visual inspection of structural and non-structural elements and context. Prior to an on-site inspection, whenever possible, inspectors should quickly review the technical documentation available for the asset to form an initial understanding for the subsequent inspection (Phares, 2004). On-site, inspectors should initially focus on the core districts, starting with critical ECs, followed by primary and secondary ECs. Next, ECs of the completion districts should be assessed. However, inspectors may encounter varying reachability/visibility limitations for different parts of the asset. Notably, direct vision is often limited to areas above the road platform, while inspection of other areas may require support equipment or devices typically provided by the managing entity. This frequently introduces considerable inspector risks. For these reasons, Unmanned Aerial Vehicles (UAVs), also known as drones or Unmanned Aerial System (UAS), have been increasingly used for bridge inspection and could greatly assist safe and effective investigation of non-directly visible components (Metni N & Hamel T, 2007; Hallermann and Morgenthal, 2014; Reagan et al., 2017a,b; Khaloo et al., 2018; Zhang et al., 2022). Drones enable remote visual inspections, providing effective support for routine surveillance activities. First and foremost, drone deployment significantly reduces safety risks for operators and inspectors (Cunningham et al., 2015; Otero et al., 2015; Zink and Lovelace, 2015; Seo et al. 2018a,b,c; Duque et al. 2018a,b). This is especially beneficial in cases where the terrain morphology or structural geometry necessitate specialized equipment such as aerial platforms or