At the A1 Birtley to Coalhouse Improvement Scheme, Cementation Skanska brought together integrity, collaboration and technical expertise to deliver complex geotechnical works for National Highways.

Working as a trusted partner to Costain and Jacobs, the team navigated challenging ground conditions and constrained rail-side operations through early engagement, shared risk models and coordinated delivery. Drawing on specialist expertise and innovative solutions — such as on-site batching and optimised sequencing — the project achieved significant carbon savings, improved efficiency and early completion, providing certainty on cost, programme and quality for this critical infrastructure upgrade.

The project

Cementation Skanska delivered multiple phases of geotechnical works on the A1 Birtley to Coalhouse Improvement Scheme in northeast England. Part of the National Highways programme, the scheme improves capacity, reliability and connectivity, including A1 realignment over the East Coast Main Line, Kingsway viaduct widening and corridor upgrades.

Appointed by Costain, alongside Jacobs, our scope covered mine treatment, rotary bored piling and rigid inclusions.

The challenge

The project combined complex ground conditions with constrained operations. Historic coal mining created variable and unpredictable geology, with depths up to 60m and significant rock drilling, alongside soft soils requiring specialist techniques.

Working adjacent to live rail under ‘any line open’ conditions and within tight sites, including Kingsway viaduct, demanded precise sequencing and logistics planning. High material demand, with peak concrete volumes of 580m³ per day, added further pressure on resources and carbon reduction.

The solution

Early Contractor Involvement enabled a collaborative approach to design, risk and delivery. Test piling validated ground conditions, while tailored commercial models aligned risk across packages.

A cost-reimbursable approach for rigid inclusions supported
close integration with Costain, optimising sequencing and constructability.

Resource resilience was secured through coordinated plant and labour, including a dedicated on-site batching plant supplying 40,000m³ of concrete.

The outcome

Over 6,500 rigid inclusions were delivered, supported by more than 35,000m³ of concrete. The on-site batching plant reduced 5,861 lorry movements and cut carbon by 62%, alongside programme and cost efficiencies.

The collaborative model drove aruond 15% cost savings and completion 55 days early, achieving a safe, high-quality outcome and supporting timely delivery of this critical infrastructure upgrade.

A1, Birtley to Coalhouse

A1 Birtley to Coalhouse Improvement Scheme

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