Excavation of Temporary Bridge Cofferdams

The Mersey Gateway

Efficient Excavation at one of the ‘Top 100 Global Infrastructure Projects’


Merseylink JV


nr Liverpool, UK

BulkX Mersey Gateway Project
BulkX Mersey Gateway Project
BulkX Mersey Gateway Project
BulkX Mersey Gateway Project


The Mersey Gateway is one of the largest initiatives in the UK, identified as one of the UK governments Top 40 Priority projects in the National Infrastructure Plan. In addition, it has been recognised as one of the ‘Top 100 infrastructure projects around the globe’.

It connects a six lane toll bridge over the River Mersey to the existing motorway network. Stretching over 2km the new bridge provides a much needed link between the towns of Runcorn and Widnes, relieving congestion from the ageing Silver Jubilee Bridge.

The Mersey Gateway Bridge includes a steel cable-stayed structure with a reinforced concrete bridge deck, supported by three towers. The supporting towers have been designed to rise between 80-125m above the river bed, spanning a distance of 1km.


The concrete foundations for the supporting bridge towers therefore, had to be built below water level. In order to maintain a completely dry environment during construction, temporary cofferdams were formed providing watertight enclosures. In order to then complete the foundations, Merseylink JV then required a method to excavate the inner circle to enable the subsequent pouring of concrete.

Excavation: 34,000m³ per cofferdam (total across the project 102,000m³) Material: Sand Challenges:

  • High risk
  • Limited operating space
  • Expensive
  • Time consuming
BulkX Mersey Gateway Project
BulkX Mersey Gateway Project
BulkX Mersey Gateway Project
BulkX Mersey Gateway Project


Conquip discussed the challenges with the planning team at Merseylink JV and identified the Bulk-X™ System as the primary solution.


  • Reduce risk – the use of the Bulk-X™ meant that operatives could work at an increased distance from the machinery and discharge.
  • Allow efficient ‘one-step’ muck away – directly from the cofferdam excavation to the muck away lorries.
  • Reduce costs – quicker and safer excavation than traditional methods.

Our specialist consultancy team then worked with Merseylink JV to establish their project-specific requirements, in order to develop a bespoke BulkX™ solution:

  • A 5000ltr Bulk-X™ Skip with a direct-to-truck discharge gantry
  • Bespoke discharge gantry which was designed to ensure the frame didn’t put too much pressure on the temporary bridge platform


"It’s a very effective system, very clean, well-controlled, overall a very good system."

Kieran Roe, General Foreman, Merseylink