The Mersey Gateway Project

Mersey Gateway’s North Approach Viaduct contains enough concrete to fill seven Olympic swimming pools

April 13, 2017Chris SealeyNews

Work on the giant North Approach Viaduct, which will help carry 60,000 vehicles a day across the new Mersey Gateway bridge, has finished.

In total, 18,400 cubic metres of concrete was used to build the viaduct, enough to fill more than seven Olympic-sized swimming pools.

Engineers and construction teams have worked on the viaduct around the clock for the past three years.

They conducted a total of 63 concrete pours, totaling 4,200 cubic metres, to create the outer deck ‘wings’ of the viaduct, 20 pours totaling 1,900 cubic metres to infill the rib and deck of the bridge, and 11 pours totaling 12,300 cubic metres for the main deck of the viaduct.

An additional 103 pours, totaling an extra 8,000 cubic metres of concrete, were achieved to create the piers that support the viaduct.

Such volumes of concrete pours require a massive amount of planning, timing and co-ordination, with each pour a highly technical process to ensure the concrete sets evenly.

While the main viaduct has been completed, a programme of extensive finishing work is ongoing.

This involves water-proofing the deck, installing fascias along its sides, and laying a road surface.

Hugh O’Connor, General Manager for Merseylink Construction Joint Venture said: “This is another big achievement for the project.

“While the main viaduct is built, it has to be properly finished before it can carry traffic,” he said.

“When complete we expect 60,000 vehicles to use the bridge every day, or nearly 22 million vehicles every year.

“This volume of traffic puts a huge demand on the road surface and structure of the viaduct, so it’s important finishing works are completed to the absolute highest standards.

“We’re working hard to complete these elements, and remain on target to open the bridge this autumn.

“The work required in conducting concrete pours is highly technical, and I would like to thank everyone involved for their contribution. Each of them is playing a vital part in bringing Halton’s iconic new bridge to life.”

A range of specialist equipment has been used to build the North Approach Viaduct, including the 280-tonne wing traveller machine, which was used to build the outer road lanes on either side of the North Approach Viaduct in Widnes.

It followed Trinity, the 1,700-tonne, 157-metre long, movable scaffold system (MSS), which built the central part of the carriageway.

Completion of the North Approach Viaduct is another significant milestone for the project.

The viaduct runs across the Widnes saltmarsh and will incorporate the slip roads for the entry and exit approaches to the Widnes side of the Mersey Gateway bridge.

Last month, construction of the bridge deck and stay cables also passed the halfway point, with construction moving forward at speed, ahead of the bridge opening this autumn.

Structural work continues on the South Approach Viaduct, which is expected to be finished in the summer of 2017.

Once complete, the two elevated approach viaducts will stretch across the saltmarsh on either side of the River Mersey, connecting the new bridge to the main road networks in Runcorn and Widnes.