Carillion / Morgan Sindall’s A1 Leeming to Barton dual carriageway upgrade has benefited from a raft of clever techniques.
As part of a £380m Highways England scheme, 20 km of the A1 between Leeming and Barton (A1L2B) in North Yorkshire is being upgraded to replace the existing dual carriageway with a dual three-lane motorway.
Once completed, the A1 Leeming to Barton project will unlock growth and boost the economy by creating a continuous motorway-standard route between London and Newcastle (including the M1 and A1M). It will also improve journey times by approximately 20 per cent and increase safety.
The Carillion / Morgan Sindall joint venture, supported by designers Aecom and Sweco, has pioneered a culture change in the highways sector through an early engagement approach and by embracing digital innovation and collaboration.
The project has taken on BIM principles, resulting in a cost-efficient construction process.
The use of BIM increased programme surety and measurable savings in excess of £3m, enabling programme to be optimised and shaving four weeks off the contract’s critical path. The team decided at an early stage to construct the project without the use of setting-out pins and to use digital machine control.
Sweco A1 Leeming to Barton Catterick Central BIM image
A pioneering design-based BIM approach allowed the use of machine control for the earthworks, slipform concrete works and the pavement. This benefited the project in terms of programme, quality, cost and health and safety.
Many benefits gained from the use of BIM are difficult to assess in monetary terms; however, the value derived from helping non-technical stakeholders visualise the project is immeasurable.
Total roads and bridges
BIM allowed adjacent landowners to understand how the scheme affects their properties, assisted non-motorised users’ groups to engage in discussions regarding provision of footpaths and bridleways, and mitigated objections to acquisition of land and property.
Additionally, the design team developed parametric milling templates allowing detailed planning and programming of the online road-widening works. This maximised the use of the existing asset by profile planning the existing carriageway, allowing the pavement layers to be milled to a level consistent with the adjacent widened carriageway.
Sweco A1 Leeming to Barton Low Street aerial 2
The templates were driven by design rules to define the depth of milling and linked to the pavement analysis.
This minimised the longitudinal pavement joints required by enabling the pavement upper layers to be laid as wide as possible, allowing for a more uniform pavement construction that ensured good productivity, quality and ease of working, ultimately providing a better ride quality. These measures in turn minimised the stresses upon the pavement, thereby improving durability and the whole-life cost of the scheme.
Validation rules were defined early in the programme by every discipline involved in the process. This included more than 250 design and construction clearance checks and more than 330 information models continually reviewed to help reduce the number of new and active clashes.
Sweco A1 Leeming to Barton Low Street BIM image
Such early engagement has greatly increased co-ordination and communication between all disciplines to generate better decisions for design, construction and maintenance.
The team introduced sustainable design and solutions, ensuring the re-use of 300,000 cu m of surplus fill material from earthworks operations, which would have previously been taken to landfill.
All excess material is used to fill a former quarry at Leeming Bar, with the aim to return the land to agricultural use and provide suitable habitat for local species. This re-use equates to 5,500 tonnes of CO2 and resulted in a cost saving of £5m – a perfect example of waste avoidance and carbon reduction.
Steven Ogbuagu is A1L2B assistant design project manager at engineering consultant Sweco