The challenge
The ground movement had caused the abutments to be dispatched towards the deck, leaving the bearings at the west end of the deck non-functional. Bridge bearing specialist Ekspan were carrying out the removal and installation of the bearings and they contacted us and consultants Arup at early contractor involvement stage.
Firstly, a hydraulic jacking scheme was needed to control the movement of the bridge during repairs.
To allow engineers to monitor the effect of the repair and deck positioning works, accurate real-time information was essential.
Our solution
We designed and developed a complex hydraulic jacking scheme with Arup to control the movement of the bridge and dispel the existing propping force into the deck to enable the safe execution of the repairs.
Built into the design was controlled live monitoring which was in place throughout the bearing removal and installation process. This monitoring ensured the bridge structure remained within the prescribed tolerances throughout the duration of the works.
32 hydraulic jacks ranging in capacity from 75Te to 300Te were used to lift the bridge vertically in order to replace the bearings. The loads on the jacks were also continually monitored, ensuring that the propping force was controlled.
By working closely with Ekspan to undertake the installation of the temporary works, and the removal and replacement of the bridge bearings, the project was delivered safely and on time.
