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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bridges, having chosen to avoid inspections on the highway bridge (top right bridge in Fig. 2). Tab. 1 summarizes the substantial characteristics of the three inspected bridges. The activities took place from July 18th to July 21st, 2022. For performing the tests, the special unit of Remote Piloted Aircraft Systems (RPAS) of the Italian National Fire Department was involved with their drone equipment and pilots.

Fig. 2. (a) aerial view of the test area; (b) teams in the command post to discuss the survey modality; (c) view of the collaborative work among university researchers, ANSFISA experts and firefighters; (d) inspection developed through the TG modality: the ANSFISA inspector works alongside with drone-pilot to guide the drone towards the areas to inspect. Photos copyright: ANSFISA, SPRINT-Lab and CNVVF.

Table 1. Summary characteristics of the three bridges assessed during the tests.

Name

Serviced road

Structural type / material Steel lattice structure

Length ( m )

Bicycle bridge

188

Alpe-Adria Cycle Path (former railway bridge)

Viaduct

State Road SS13

Concrete elements Masonry arches

190 120

Former road bridge

Disused road

The conception and design of the experimentation were carried out by SPRINT-Lab researchers, taking into account their previous experiences of collaboration with firefighters in emergency scenarios within the Short Term Countermeasure System (Grimaz et al., 2016). ANSFISA experts were involved during all the experimentation phases, playing the active role of inspectors with the possibility of having the support of drones piloted by firefighter specialists. Different strategies were tested to obtain overviews and details, involving the systematic survey of bridges using both TG and TC approaches. The aim was to compare timing, data quality and quantity, and overall effectiveness in relation to the VISIT-bridge requirements. The drone operators were experienced RPAS firefighters, who have rotary-wing drones (model Matrice 300 RTK, see DJI, 2023a). While this drone requires limited takeoff and landing space, it has less flight autonomy compared to fixed-wing drones, but better tolerates windy conditions. Drone was equipped with a LiDAR and a photogrammetry camera (see DJI, 2023b,c for specs). The 3D reconstruction software also allows users to pre-plan and load flight information, including flight plan characteristics and considerations like wind, sun exposure, and designated areas. The TC methodology was developed autonomously by RPAS pilots and provided to ANSFISA experts after the completion of survey and elaboration activities. In average, for the comprehensive reconstruction of the 3D model of