Bridge Resilience in Landslide-Prone Areas: National Guidelines and Prioritization Indices for Strategic and Insightful Risk Assessment

In a nation like Italy, where a significant amount of the national bridge network was created decades ago and is currently vulnerable to aging, increased traffic loads, and environmental hazards, the safety and longevity of existing bridges are essential to guaranteeing the dependability of transportation infrastructure. In response to growing safety concerns and high-profile structural failures, such as the Morandi bridge collapse, Italian institutions have introduced new regulatory tools to standardize the evaluation and management of bridge risks. The application and analysis of the "Linee guida per la classificazione e gestione del rischio, la valutazione della sicurezza ed il monitoraggio dei ponti esistenti" (Guidelines for the Classification and Risk Management, Safety Assessment, and Monitoring of Existing Bridges) are the primary focus of this thesis. Of particular importance is the methodology used to assign a Class of Attention to each bridge, based on different types of risk. The research employs the whole four-level evaluation technique provided by the Guidelines ranging from data collection and preliminary classification to detailed technical assessments on a selection of case studies. Every bridge undergoes a methodical evaluation to ascertain the most important risk factors be they environmental, geotechnical, or structural, and to rank them in order of importance. The objective is to give a thorough summary of how the Guidelines aid in infrastructure management decision-making and to show how they may be used practically to categorize risks and schedule maintenance procedures. Finally, the thesis extends the analysis through the calculation of a Priority Index, offering a two-phase ranking tool. The census-based index first highlights structures that require closer scrutiny, while the total index integrates direct inspection evidence to refine the prioritization and identify cases demanding urgent intervention. The combined use of these tools illustrates how the Guidelines enable a rational, transparent, and multi-hazard approach to infrastructure risk management, enhancing both the efficiency and effectiveness of maintenance planning. This integrated framework ultimately ensures that limited resources are directed where they are most needed, strengthening both the safety and resilience of Italy’s bridge network.