PSI - Issue 84

Lorenzo Brezzi et al. / Procedia Structural Integrity 84 (2026) 505–512

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and impulsive landslide phenomena, such as rockfalls and debris flows. In these scenarios, risk management cannot rely solely on the absence of current damage, but requires a detailed understanding of terrain morphology, potential detachment zones, runout paths, and residual hazard thresholds derived from past events. Special inspections therefore play a crucial role in structuring advanced geomorphological analyses and supporting the modelling of residual risk, which is essential for ensuring an adequate level of safety under highly uncertain and potentially catastrophic conditions. Finally, Case A demonstrates the relevance of SIs in the long-term management of bridges historically affected by landslides and subsequently stabilized through mitigation measures. In these cases, the inspection effort is primarily focused on verifying the continued effectiveness of the adopted interventions and monitoring systems, allowing potentially stabilized situations to be managed with a limited but technically adequate effort, while maintaining a high level of safety control. Overall, the three case studies confirm that special inspections are a key tool for uncertainty reduction and proportional decision-making within large bridge networks. By enabling the calibration of investigation depth and monitoring strategies to the actual landslide–bridge interaction scenario, the proposed approach supports the development of operational Guidelines for Special Inspections for Landslide Risk Assessment (LLGGIS), contributing to more efficient, sustainable, and safety-oriented infrastructure management at the network scale. Acknowledgements Part of the work was made possible through funding for the PhD scholarship of Fabiola Gibin provided by the European Union – NextGenerationEU (National Recovery and Resilience Plan – NRRP, Mission 4, Component 1, Investment 4.1 – D. M. 118/2023, CUP C96E23000880001). The authors would like to thank Tecne S.p.A. for the financial support provided for the PhD scholarship of Alessandro Scala. References Bazzucchi, F., Restuccia, L., Ferro, G. A., 2018. Considerations over the Italian road bridge infrastructure safety after the Polcevera viaduct collapse: past errors and future perspectives. Fracture & Structural Integrity 12. https://doi.org/10.3221/IGF-ESIS.46.37 Burlando, M., Romanic, D., Boni, G., Lagasio, M., Parodi, A., 2020. Investigation of the weather conditions during the collapse of the Morandi Bridge in Genoa on 14 August 2018 using field observations and WRF model. Atmosphere 11(7), 724. https://doi.org/10.3390/atmos11070724 Cruden, D.M., Varnes, D.J., 1996. 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