Insights into Landslide Interaction with Bridges and Viaducts: Lessons from Italian Case Studies and Database Analysis

The study of landslides and their impacts on infrastructure has assumed an increasingly significant importance in recent years. Landslides, along with floods and earthquakes, are natural disasters responsible for severe socioeconomic and human losses. Italy, with its complex geological and geomorphological structure, has historically experienced a high occurrence of landslides caused by both natural and human factors. Notably, viaducts and bridges are frequently affected by landslides that may produce damage to their structural components or, in the most severe cases, complete collapse. To analyze the complex mechanisms of interaction between a bridge and a landslide, a comprehensive database of case studies concerning bridges located in Italian territory, which have been inspected by various Universities participating in the FABRE Consortium, has been implemented. Such database records detailed information related to the examined structures, in compliance with the "Guidelines for the classification and management of risk, safety assessment, and monitoring of existing bridges"(provided by the Italian Ministry of Infrastructure and Transport). First, the database contains information regarding the presence or absence of landslides that may partially or fully interact with the structures under analysis. Secondly, it provides specific kinematic details about the type of landslide movement, its activity status, volume, and velocity. Finally, information about landslides and interacting bridges are used to evaluate susceptibility, vulnerability, and exposure classes associated with landslide risk. This assessment helps define the corresponding Attention Class (AC), as per the definition in the Guidelines. Most importantly, a thorough analysis of the case studies collected in the database has led to the development of significant statistical insights, revealing the relevance of different recurrent landslide features in the assignment of the landslide AC to viaducts. This contribution aims at enhancing the comprehension and the effective management of landslides within Italy's road infrastructure