PSI - Issue 84

Mirza Adeel Zeb et al. / Procedia Structural Integrity 84 (2026) 248–255

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Landslide activity ( P a ) has been mapped considering documented states within the Italian Landslide Inventory (IFFI). Only landslides classified as active, inactive, and stabilized were included in the analysis. Landslide magnitude ( P m ) was estimated to use the empirical relationship between landslide volume ( V L in m 3 ) and area (A L in hectares)proposed by Guzzetti et al. (2009). Landslide velocity ( P v ) has been quantified by means of satellite-based ground motion data provided by the European Ground Motion Service EGMS. Ground deformation velocities along the satellite line-of-sight were obtained via Persistent Scatterer Interferometry ( PS-InSAR ) using Sentinel-1 radar data collected between 2019 and 2023. For each landslide, the maximum deformation velocity was calculated within a 300-meter buffer zone surrounding the bridge structure. Subsequently, each bridge was assigned a velocity based on the threshold values defined in the national guidelines. Geospatial analysis of the study area was conducted using the QGIS platform, incorporating spatial data layers including the location of bridges, landslide polygons, and the broader study area. The three hazard parameters were integrated within the procedural framework outlined by the guidelines, following the prescribed steps and classification system for determining the appropriate attention classes. This classification supports the prioritization of monitoring and maintenance interventions for each bridge. 3. Estimation of landslide susceptibility of the Caserta Province 3.1. Geomorphological context This study analyses 250 existing bridges located in the province of Caserta, southern Italy, a region with varied geomorphological features. A previous and comprehensive study of all the bridges has already been conducted, including their classification according to typology, geometry, and construction materials. Visual inspections were performed on a large subset of the bridges to assess the state of conservation and identify the most recurrent defects. Additionally, a Level 2 assessment of structural and seismic performance was carried out in accordance with Italian guideline s, with details of the surveys, inspections, and structural assessments reported in Bencivenga et al. (2021, 2023) and Zizi et al. (2023). Building on this foundation, the current study examines the geomorphological context and assesses landslide susceptibility as an external hazard to bridge infrastructure at the territorial scale.

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Fig. 1. (a) Digital elevation model (DEM); (b) Slope gradient map derived from the DEM.

This research focuses on geomorphological and landslide susceptibility aspects. The first step of the analysis involved describing the geomorphological context of the study area. Caserta, located in the Campania region, encompasses mountainous, hilly, and alluvial areas, making it a suitable case study for investigating the interaction between bridge infrastructure and landslide-prone terrain, as previously addressed by the authors. The Digital Elevation Model ( DEM ) of Caserta territory, depicted in Fig. 1, was used as a topographical base to derive the critical