PSI - Issue 84

Davide Caliò et al. / Procedia Structural Integrity 84 (2026) 513–520

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Figure 3) UAV-based analysis of the slope at the viaduct abutment in the direction of Syracuse, affected by instability conditions. (a) UAV aerial image with a close-up of the linear anomaly.(b) RGB 3D model of the slope. (c) Detailed structural and kinematic analysis of the exposed rock face: stereographic projection showing the main discontinuity sets and the results of the kinematic assessment.

5. Discussion and Conclusions The results demonstrate the effectiveness of a multisensor UAV-based workflow for the integrated inspection of viaducts located in geologically and geomorphologically complex environments. The integration of RGB photogrammetry and infrared thermography enabled a high-resolution three-dimensional characterization of both structural elements and adjacent slopes, allowing the identification of critical features that are not easily detectable through conventional ground-based inspections. From a structural perspective, the IRT analysis provided significant added value compared to RGB imagery alone, enabling the identification of different stages of concrete degradation and the detection of potential early-stage corrosion processes that were not yet visually evident. At the same time, the geological and geomorphological analysis highlighted the role of slope structure and gravitational instability processes as relevant controlling factors for infrastructure safety, particularly in fluvial settings. The study confirms that an integrated three-dimensional approach, combining structural, geological, and thermal data, enables a more reliable assessment of viaduct vulnerability, providing a non-invasive and transferable workflow to support infrastructure management and risk mitigation. Figure 4 (a) RGB view of the slope adjacent to the viaduct abutment showing a linear surface anomaly (white arrows). (b) Night-time and daytime thermograms highlighting the same feature,