Client
Southampton City Council
Value
£2.2M
Sectors & Services
Highway Structures Concrete Repair Coatings Membranes Grouting & Injection Bearing Replacement Projects Projects
The Redbridge and Millbrook Roundabout Flyovers are key reinforced concrete highway structures carrying the A33 dual carriageway, the principal route into Southampton city centre. Owned and maintained by Southampton City Council, the flyovers are critical to daily commuter, commercial and port-related traffic.
Over time, increased loading, general wear and inadequate abutment drainage led to deterioration and failure of the existing pot bearings. A major bearing replacement scheme was therefore required to maintain structural integrity, ensure safe operation and extend the service life of these strategic assets. The works were carefully planned to minimise disruption while addressing essential long-term asset management requirements.
Replacement of 64 pot bearings on highway flyover structures
Excavation around piers to foundation level
Installation of extensive temporary propping systems
Hydro-demolition for concrete removal and bearing extraction
Re-profiling of abutment bearing shelves
Precision installation of new bearings weighing up to 250 kg
Recasting of concrete and grouting of bearing plates
Replacement of bridge expansion joints
CRL was appointed to deliver a complex bearing replacement scheme involving the removal and replacement of 64 pot bearings across the Redbridge and Millbrook Roundabout Flyovers. All pier bearings, with the exception of the central fixed pier bearings, were replaced. The retained fixed bearings were prepared and painted as part of the overall durability works. Replacement activities required excavation around the piers down to the top of the foundations, followed by the installation of extensive temporary propping to safely redistribute loads during the works.
Given the importance of the A33, traffic disruption was kept to an absolute minimum. The carriageway remained open throughout the project, with only limited night-time closures during critical jacking operations. Temporary works were designed to allow the bridges to be lifted in a fully controlled manner, supported by precise, computer-controlled 24-hour monitoring to ensure structural movements remained within strict tolerances.
At the abutments, bearing shelves were re-profiled to facilitate access for jacking and bearing removal. The fill behind the abutment walls was stabilised using permeation grouting to prevent movement and loss of support. Hydro-demolition was then used to remove concrete in a controlled manner, minimising vibration and protecting adjacent structural elements. The bearing shelves and abutment walls were subsequently recast to provide permanent access and reinstated structural capacity.
With the jacks locked off, the existing bearings were removed using hydro-demolition techniques. New pot bearings, weighing up to 450 kg, were installed using a specialist positioning method developed by CRL, enabling precise placement within confined working conditions. Following installation, concrete was recast and bearing plates were accurately grouted. In parallel, expansion joints on both flyovers were replaced and a new drainage system installed. This integrated approach highlights CRL’s expertise in complex concrete repairs and structural repairs UK projects, delivering technically robust solutions while preserving network operation.
“A pleasure to work with – good focus on getting the job done!”
John Simpkins | Senior Engineer | Southampton City Council
The scheme incorporated measures to enhance long-term durability and protect the flyovers against future deterioration. Improved abutment drainage addressed one of the original causes of bearing failure, reducing the risk of water ingress and associated damage. Controlled hydro-demolition ensured high-quality surface preparation, promoting strong bonding of new concrete and long-term performance. Preparation and painting of the retained central fixed pier bearings provided additional corrosion protection.
Accurate grouting of bearing plates ensured effective load transfer and reduced the potential for differential movement. Combined with new expansion joints and improved drainage, these measures significantly reduce future maintenance requirements and improve structural resilience. Through careful planning and technical execution, CRL helped Southampton City Council extend the service life of these vital structures and protect a key transport corridor through effective asset management.
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