Redbridge and Millbrook Roundabout Flyover, Southampton, is a joint project CRL is currently carrying out for Southampton City Council. The two flyovers support the A33 which is the principle route into Southampton, and it is crucial that disruption is kept to a minimum.

Scope of Works:

• Re-profiling of the bearing shelf to each abutment
• Permeation grouting to support the fill behind the abutment
• Extensive jacking and propping
• Replacement of bridge bearings
• Installation of replacement Expansion Joints

The re-profiling of the bearing shelf on each abutment involved hydro-demolition followed by permeation grouting to support the fill behind the abutment with additional installation of new reinforcements and re-castings of the bearing shelf and wall. The bearings to each abutment are being moved following the installation of temporary works and jacking and new bearings installed. Any new concrete is to be treated with as silane or waterproof coating.

To all piers other than the central fixed pier (to which the bearings are to be prepared and painted), bearings are to be replaced. This work will involve excavation around the piers down to the top of the foundation.

Extensive temporary works have been installed seeing the bridges jacked in a controlled manner with careful monitoring and the jacks locked off with the existing bearings will being removed using hydro-demolition.

The bearings are being installed with a Telehandler and sliding rollers. After the new bearings are installed the bridge will be de-jacked again under careful monitoring. Expansion joints on both bridges are to be replaced incorporating a drainage system.

Client:             Southampton City Council

Value:             £2 million