The 60-year-old Clifton bridge runs over the M6 and forms part of the West Coast Main Line in Cumbria. It has reached the end of its life and needs to be replaced.
Skanska is working as main contractor for Network Rail, with the new 4,200 tonne steel bridge currently being constructed adjacent to the M6. During the design phase, Skanska worked closely with Network Rail and the design team to find ways to reduce materials waste, cost and programme timescales.
This led to a solution where the existing bridge abutments, which the bridge sits on either side of the motorway, are being carefully retained and strengthened to accommodate a new, wider bridge design that supports higher loads.
Cementation Skanska completed temporary works, on and around the abutments, which includes the installation of reinforced walls and working platforms. On the west side, this has involved the use of Legato blocks, an efficient and cost-effective solution. In total, Cementation is installing 130 piles and 89 ground anchors.
Cementation Skanska’s Managing Director Andy Entwistle said: “Key to the ground engineering works has been the management of risk. We have self-delivered the temporary work Legato block walls on the west abutment as well as the piling platform and installation of mechanical anchors and wailing beams on the east abutment. This has significantly reduced the number of package interfaces, which has resulted in safer site delivery while maintaining the project programme.”
Subcontractor Kilnbridge is carrying out strengthening works, including on the central pier support, which is located between the safety barriers in the middle of the motorway.
Given the close proximity of the pier and abutments to the busy M6 motorway, the work has involved careful planning and preparation. Structural monitoring throughout ensured that all work was completed to design specifications.
Compared to installing new abutments and piers, this engineering solution led to a range of benefits. The modifications to existing elements ensured that both rail and highway networks could remain fully operational, minimising disruption to transport services. By reusing structural elements that are still fit for purpose reduced material usage and waste, enhancing sustainability.
Will Brandon, Network Rail project manager, said: “The fact that these works have caused minimal disruption to both local and motorway traffic and reduced site waste during the last 11 months is testament to Skanska’s considerate and environmentally conscious approach.
“Getting the ground engineering works right is setting up the project in good stead for keeping to programme, especially during our 15-day closure of the West Coast Main Line which is fast approaching at the end of December.”
Skanska’s Rail Programme Director Rosario Barcena added: “Time spent on the early design and constructability phase is now really paying dividends during delivery.
“The thoughtful planning of the work has minimised the impact on local communities and travelling public. We’ve also found ways to reduce cost and material waste, which is the right thing to do for society.
“The team is making great progress and we’re fully focused on preparations for the blockade, when the current bridge will be removed and the new one installed, which starts on 31 December. “
The ground engineering works have created the space needed for the self-propelled modular transport system (SPMTs) which will be used to manoeuvre the new bridge from its current location into position during the 15-day blockade from 31 December.