Runcorn Viaduct is a Grade II listed structure that crosses the River Mersey and the Manchester Ship Canal from Runcorn to Widnes in Cheshire.
The scope of works included:
- Slung scaffold installed across the River Mersey with a moveable Cradle installed above the Manchester Ship Canal span.
- Canal works were restricted by the continual passage of ships beneath the structure; the cradle would need to be moved to allow the tallest ships to pass.
- Grit Blasting followed by the application of 23,000 litres of protective Glass Flake epoxy
- Steelwork repairs to the soffit area with confined space work inside the structure.
Carrying the two tracks of the Liverpool Branch of the West Coast Mainline 23m above the high water mark; the bridge consists of three wrought iron lattice girder spans of 93m. Taziker Industrial (TI) were awarded the contract to refurbish the soffit areas of the 140 year old structure.
The structure was washed and then blasted with iron silicate abrasive to reveal what was under the generations of grime, then the steelwork was dried and detailed inspections were carried out, leading to an inventory of structural and condition led repairs. Finally, the team coated the structure in a protective treatment that will ensure the soffit area of the structure will be protected for at least another 25 years.
The access system for the river spans was complex slung scaffold. In order to allow tall vessels the continued use of the Manchester Ship Canal, the canal span section was accessed by a travelling cradle, which can be winched along the structure to allow the passage of vessels below.
The environmental issues had to be taken very seriously, for despite the industrial landscape, there were two major designations to consider. The Runcorn Gap which the structure spans is a SSSI (Site of Special Scientific Interest) and is also covered by the RAMSAR convention for wetlands of international importance. By utilising the Envirowrap system, we could ensure that no contaminants generated during the grit blasting or painting process could leave our encapsulated area.
Learning and Innovation
At TI, we always go to great lengths to ensure that our people stay safe. When working on structures that span the water, we always have a rescue boat on hand in the unlikely event that someone should enter the water. In this case, the work was being carried out over the Runcorn sand flats, and a rescue boat would have been useless at low tide. So we bought a rescue hovercraft to give rapid coverage over both the water and the treacherous sand flats.