Curved beams raise Mersey bridge pylons

Four hundred tonnes of curved heavy steel sections have been supplied by Barnshaw Section Benders for the construction of the Mersey Gateway Bridge.

The steelwork is being used to form cofferdams that create a safe working environment for the construction of the bridge’s three main pylons.

The work to create the cofferdams involved driving steel sheet piles into the riverbed to form an outer circle with a diameter of 40m and a second inner circle with a 20m diameter.

The steel piles needed to have some reinforcement fitted so that they can cope with the pressure. This came in the form of huge steel sections that have to be strong enough to support the piles and curved to match the radius of the inner circle.

The steel sections measure up to 356mm x 406mm, weigh 467kg/m and are formed to a radius of 9.7m so as to fit on the inside of the steel pile structure.

Barnshaws Commercial Director Greg North said: “We often work on large structural steel sections, bending them to add strength to a structure, improve the aesthetic qualities of a project, or, in this case to fit a precise curved profile.

“In all, we have formed nearly 400t of this heavy duty steel section to the exact requirements of the client. They will provide the strength necessary to hold the shape of the cofferdams while the foundations of this new river crossing are constructed.”

The cable-stayed bridge will have a total length of 1,000m spanning the river Mersey and the Manchester Ship Canal to provide three lanes in each direction, linking the Central Expressway in Runcorn with the main routes to the M62 and towards Liverpool.