The Gerber bridges in Italy: retracing history to safeguarding existing infrastructures

The static scheme of the Gerber beam was formalized in 1886 when the Bavarian engineer Heinrich Gerber (1832-1912) filed the patent "Balkentrager mit freigenden Stuntzpunkten," introducing the concept of internal hinges within the continuous girder static model. By the 1890s, large metal viaducts constructed applying the Gerber scheme became widely adopted. Subsequently, from around 1930 onwards, the Gerber scheme was extended to reinforced concrete bridges. In Italy, the Gerber scheme was widely applied to reinforced concrete bridges from the 1930s to the 1970s. In this context, the Gerber scheme evolved with the technological advancements in reinforced concrete construction, adapting to the gradual integration of prefabrication techniques, prestressing methods, and the industrialization of castings. The present paper retraces the evolution of the reinforced concrete Gerber bridge in Italy, proving the knowledge base framework for the actual assessment and maintenance intervention on existing bridges.