PONTI STORICI TRA SICUREZZA E CONSERVAZIONE. STRATEGIE DIAGNOSTICHE PER UN USO COMPATIBILE.

Bridges and transportation infrastructures of the past represent an important part of the historical heritage, bearing witness to the distinctive characteristics of construction methods — mainly related to masonry and iron structures, but also to the early developments of reinforced concrete. This paper proposes thoughts on the challenges and possible conservation strategies for historic bridges, balancing the needs for safety of users and the protection of the heritage values. Codes and regulations concerning infrastructures do not consider differentiated safety requirements for historical and new bridges; additional challenges include the increase in demands both in terms of traffic and in the weight and speed of vehicles. Significant issues are triggered by climate change, with sudden changes in water regimes and disastrous floods. In addition, the lack of targeted investigation and analysis procedures for the systematic monitoring of these important heritage structures leads to widespread distrust in their actual effectiveness and loadbearing possibility. In this context, long-term dynamic monitoring can be an effective tool to understand and control the performance of historic bridges over time under operational conditions and to detect the onset of damage. The aim of the research is to explore the challenges and suggest cultural and methodological guidelines to ensure the continued use of historic bridges in full compatibility with the capacity of the structures.