Modernising a monument: The challenges of strengthening and widening a structurally deficient road bridge under live traffic

Abstract The historic Port Weir Bridge over the Nidau‐Büren Canal in Canton of Bern, Switzerland, was inaugurated 1938. This multi‐purpose structure serves as an important road bridge, a mechanised weir, lock for canal boats, well hydroelectric power station. During inspections 2018, severe concrete damage and reinforcement corrosion were observed on this protected structure. Immediate temporary measures required conformity factors structural safety at numerous locations significantly below minimum requirements. A project specific traffic load model allowed strengthening works to be limited few critical elements, thereby allowing bridge reopened heavy 2019 then fully rehabilitated between 2020 2022. renovation involved innovative reinforced UHPFRC existing T‐beam superstructure widening deck bring lane widths up modern standards. paper outlines concepts applied, some key construction challenges associated with maintaining during works. Additionally, concept is demonstrated by means design example.