A major 6-month contract has been completed at Walton New Bridge, Warrington. The refurbishment project was carried out for Warrington Borough Council after the Council investigations had identified the concrete deterioration and required a durable long-term remedy to minimise future maintenance costs on this strategic structure.

Scope of Works:

• Repair of 6.5 cubic metres of concrete
• Design and installation a full impressed current cathodic protection (ICCP) system
• Application of fairing coats and anti-carbonation treatments
• Improvements to the drainage in the cantilevers.

Built in the late 1930s, Walton New Bridge carries the A56 over the Bridgewater canal. The structure is very distinctive due to its unusual three long-span bowstring beams, which rise to form a bow shape above the two carriageways below. The design of the ICCP system proved complicated because of the high steel densities in each beam, as well as the bridge’s 30-metre span and 45 degree skew. The problem was exacerbated by the additional discontinuous steel, such as crash barriers and pedestrian walkway plates, which had to be connected into the system to avoid stray current corrosion. The final design comprised of 31 separate anode zones, using 1000 square metres of titanium mesh anode with a sprayed overlay. The power and computer control systems were provided by Electro-tech CP, with a modem link to enable remote management of the system.

All refurbishment work was undertaken while the road above remained fully open and the canal and its towpath also continued in operation. To comply with Environment Agency standards for working over water, dust and debris was contained within an enclosed work area for safe off-site disposal and water used in the cleaning process was filtered before discharge. All environmental procedures were agreed with the Agency before the work began and were carefully monitored throughout the course of the complex project.

Phil Townend of Warrington Borough Council commented “Walton New Bridge has been returned to a structurally sound condition thanks to CRL’s efforts. The company’s work is first rate and very neat, especially the extensive arrangements of wiring and half-cells hidden within the sprayed overlay”.

Client: Warrington Borough Council

Value: £500,000.00