Strengthening of the A52 Clifton Stage 2 bridge in Nottingham

The A52 Clifton bridge is a 6-span post-tensioned concrete bridge, which carries the A52 trunk road in the City of Nottingham (UK). The bridge was built in the early 1970’s and comprises two distinct bridges: the South Approach Viaduct and the Main Bridge over the River Trent. In February 2020, severe corrosion was identified within the external strands inside the South Viaduct. Lane restrictions were implemented while further investigations confirmed additional corrosion in the prestressing strands for both superstructures. The assessments revealed shortfalls in strength and led to the design of a deck strengthening solution using additional prestressing tendons. This paper describes the strengthening solution for both superstructures including the construction sequences and discusses the destressing works of a selected number of external redundant strands within the Main Bridge allowing the new strengthening tendons to be fully jacked to their final specified forces.