The Mersey Gateway Project

Mersey Gateway: fascinating facts

October 13, 2017adminNews

“As one of the largest infrastructure projects in the UK the numbers behind Mersey Gateway are staggering. The scale and complexity of the engineering and construction activity is phenomenal.

Some of the figures involved show that delivering this project on schedule and under budget is an incredible achievement. I’d like to say well done to everyone involved – the construction team, the council team and the tolling teams and very importantly – the Merseylink volunteers – for making such a vital contribution.”

Cllr. Rob Polhill, Leader, Halton Borough Council

Headline facts:

The main cable stayed bridge is 1km long and made predominantly of concrete and reinforced steel.

The deck of the bridge is roughly 25m above the river bed and is around 2.2km long when you include the north and south approach viaducts.

The stunning new bridge is the centrepiece of the project, but Mersey Gateway is about much more than just a bridge. The project includes or will have used: 

  • 2km of bridge and road with 7 new or upgraded junctions
  • 12 new bridges across Halton
  • 810 miles of cables – almost enough to stretch from Lands End to John O’Groats
  • bridge has a weight bearing capacity of 53,500 tonnes – equivalent of the QE2 cruise ship
  • 239 massive beams – each one up to 40m in length and weighing up to 106 tonnes
  • 127,415 m3 of concrete.

It will have taken 1200 days (42 months) to build from start to finish.

The key background statistics:

  • 60mph speed limit across the bridge
  • 3 lanes in each direction across the river
  • 20million vehicles a year are expected to use the new bridge
  • 90,000 vehicles have registered for discounts or free crossings
  • it has taken three and a half years to build
  • £1.86 billion throughout project duration through to 2044, includes design, build, finance, operation and maintenance.
  • £250million saved on the budget 

A bridge to prosperity:

The new bridge and the improvements along the route are all about delivering benefits for Halton and the surrounding area.

  • Almost 5,000,000 man hours / days spent on construction
  • More than 25,000 people from at least nine countries across the globe have worked on the project
  • more than £129million of work put into regional economy across hundreds of different suppliers and sub-contractors

Economic and transport benefits:

  • Estimated 4,640 permanent jobs created,
  • £61.9 million per year in gross value added from new jobs by 2030.
  • Reduction in traffic times during peak hours.

Environmental benefits:

  • 1,423,250 tonnes of contaminated soil made acceptable for re-use
  • 2,341,450 litres of liquid materials removed from the site and disposed of safely
  • 36,785,000 litres of liquid cleaned up by passing through our water treatment plants

Community engagement benefits:

  • over 20,000 hours of support to local projects delivered through the Merseylink TimeBank scheme
  • £121,000 worth of community benefits delivered locally across 18 separate projects in Runcorn and Widnes through the Merseylink TimeBank scheme and regeneration fund. Initiatives ranged from creating nursing home peace gardens to nursery school play areas
  • 30,000 people visited Visitor Centres locally
  • 73 weeks of work experience delivered for local students from a variety of schools and colleges within Halton and the immediate surrounding areas.
  • 92 local volunteers making a massive contribution to sharing the Mersey Gateway story with young people and the local community
  • Delivered presentations and Lego sessions to over 2,200 children in 71 primary and secondary schools

The major pieces of machinery used to construct the main bridge: 

“It is the skill and ingenuity of our team that has made delivering this project possible but to achieve it in three and a half years we’ve constructed and used some incredible machinery to help us along the way.”

Hugh O’Connor, General Manager, Mersey link

Tower Cranes

The three giant tower cranes dominated the Halton skyline for months as the three bridge pylons that give the bridge its unique design were constructed upwards from the river bed.

There are three rather than two pylons because of height restrictions caused by planes flying into the nearby Liverpool John Lennon Airport.

Their heights were:

  • north pylon 110m high with a final crane height of 129m
  • central pylon 80m high with a final crane height of 100m
  • south pylon 125m high with a final crane height of 146m

Trinity and Webster – our Moveable Scaffold Systems (SMSs)

Trinity and Webster each weighed 1700 tonnes, were 157 meters in length, 8m high and 22m wide.

Trinity cast 750 metres of road deck along the north approach viaduct with 11 enormous concrete pours. Approximately 1,100m3 of concrete was poured for each section, and each one took around 26 hours to complete.

Webster cast 720 metres of road deck along the south approach viaduct including one section across the Manchester Ship Canal. She spent much of her time working 40 feet above the ground on Astmoor Viaduct.

Approximately 1170m3 of concrete was poured for each section – making each one the equivalent of 200 cement trucks.

Both MSSs have been recycled and sent to Bratislava in Slovakia to build a new bridge over the Danube.

Six Form Travellers

Each weighing 270 tonnes, these were lifted up to bridge deck height using hydraulic ramps. Three pairs acted as cantilevered form work to construct the one kilometre long bridge deck in 6m long and 33m wide sections.

There are 154 deck segments in total. 

Two Wing Travellers

Each weighing 280 tonnes, these 48m wide and 20m high machines were used to cast the additional lanes onto north and south approach viaducts.

They cast 12m sections along each side of the viaduct.

Striking features:

Temporary cofferdams

The team constructed three temporary cofferdams – which you can still see in the river today – to create dry working areas to lay the concrete base for the pylon foundations. The three foundations sit below the riverbed and each measure 4.5m (h) and up to 22m in diameter. Each cofferdam is approx. 40m in diameter and about 25m deep.

They will be removed over the coming 12 months along with the 1,000metre long temporary trestle bridge.

Stay cables

There are 146 cables in total and they are spread across the 3 different pylons to reflect the heights of the pylons i.e. 62 on the south, 30 on the central and 54 on the north pylon.

They range in size between 41m and 226m from top to bottom and there are between 41 and 91 individual strands within each cable from bottom to top.

Each strand has a load bearing capacity of about 27.9 tonnes.