PSI - Issue 78

Carla Grandón-Soliz et al. / Procedia Structural Integrity 78 (2026) 1505–1512

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The Italian Guidelines establishes a hierarchical and progressive approach for managing the safety of existing bridges, aiming to ensure functionality, operability, and resilience of transport infrastructure in the context of structural and hydrogeological risk. It identifies a workflow structured into five levels of intervention (Levels 0 to 5), organized according to the required degree of structural attention. Synthetically, the Level 0 includes the geolocation and inventory of structures, followed by basic visual inspections, while Level 1 draft defects of the bridge. Based on this initial information, a n “attention class” is assigned to each structure, categorizing it into five levels: high, medium-high, medium, medium-low, and low. guiding the subsequent actions based on the assessed risk (Level 2). Bridges classified with a high or medium-high attention are subject to a preliminary evaluation (Level 3), which may include extraordinary inspections or continuous monitoring, depending on structural criticality. For cases involving significant vulnerability - due to structural type, materials, or location in areas affected by active hydrogeological phenomena - a detailed structural assessment (Level 4) is necessary. The latter involves in-depth structural analysis, numerical modeling, and verification in accordance with current design standards. Throughout the entire process, the use of a surveillance and monitoring system is foreseen to ensure continuous structural performance tracking. Additionally, the integration of a Bridge Management System (BMS) is encouraged to support efficient planning of maintenance interventions and the continuous update of the assigned class of attention. Finally, for structures of strategic importance, Level 5 is dedicated to the evaluation of network resilience, focusing on the infrastructure’s ability to maintain functionality during extreme events or emergencies. In this study particular attention is paid into the Level 0 (i.e. inspections): with reference to the explanatory case study of the Fisculco bridge inspections were carried out aimed at identifying the main structural and typological characteristics of the building and of the surrounding area. In this first phase – preparatory to detailed on-site inspections which will be conducted on site by the authors - the inspections were conducted remotely, thus testing the potentialities of crowd-based paradigm into supporting data collection and the seismic risk assessment of existing bridges, as discussed in the following. 3. Crowd-Based Inspection of the Fisculco Bridge The Fisculco Bridge stands as a landmark in Bolivian civil infrastructure. Situated along the Jaime Mendoza Diagonal Route between Sucre and Ravelo, it is the tallest bridge in Bolivia, rising 123 meters above the riverbed and spanning a total length of 310 meters. The pile (column) on the Sucre side is 51 meters high and the one on the Ravelo side is 45 meters. According to data provided by the Bolivian Road Administration (ABC), the bridge's superstructure is composed of three continuous spans formed by variable-depth, mono-cellular box girders made of post-tensioned concrete. The individual span lengths are 87 meters, 140 meters, and 73 meters, respectively, complemented by two 5-meter approach spans on either side (Correo del Sur, 2020). Constructed using the successive cantilever method and featuring post-tensioned concrete box girders, the bridge's structural complexity highlights the critical need for dynamic analysis and continuous monitoring — particularly in a national context where bridge design and safety regulations remain underdeveloped. The structure was funded through a mixed public investment (70% CAF and 30% departmental government), with a total budget of approximately Bs 61 million (~USD 9 million). The inspection of the bridge was conducted according to crowd-sourcing paradigm, which is an approach based on collection of data coming from the web, thus exploiting the potentiality of remote-sensing. As it emerges from the literature, such an approach appears effective into supporting typological and structural recognition of structures (Columbro et al. 2022, Sandoli et al. 2023, Sandoli et al. 2024). With reference to Fisculco Bridge, a cross-platform analysis was conducted drawing from social media, news portals, and mapping technologies. Data sources include: social media (X- formerly Twitter, Facebook, Instagram, TikTok), Mapillary, OpenStreetMap, Google Maps, Mapcarta, Bing Maps, Yandex Maps, and Google Earth, as well as Scribd-hosted technical documents and national news media (e.g., Correo del Sur, Infodiez, Eju.tv, La Época, Red Uno Sur), as collected in Table 1 and discussed in the following.