Plans for the A303 Amesbury to Berwick Down scheme would see a 3.2km tunnel built under the National Heritage Site, 50m away from the current route of the A303.
National Highways has now awarded its £60M Delivery Assurance Partner contract to Costain and Mott MacDonald. The two engineering giants will provide technical and construction management expertise by helping mobilise the main works contractor, oversee construction, assist the discharge of consent requirements and assure the design.
It comes after National Highways selected a joint venture comprising Spain’s FCC Construcción, Italian firm WeBuild and BeMo Tunnelling from Austria to deliver the £1.25bn contract for the tunnel, along with the main construction work for the A303 Amesbury to Berwick Down scheme past Stonehenge.
The contract is subject to final sign-off on the scheme by transport secretary Anne-Marie Trevelyan, with its planning application still pending redetermination after the decision to grant the Development Consent Order (DCO) was originally quashed.
National Highways project director for the A303 Stonehenge scheme Derek Parody said: “We’re pleased to have brought in a team of expert contractors. The main works contract will only become live once the secretary of state has concluded the planning process.
“The announcement in no way pre-empts any decision, and once that is finalised, and should the DCO be granted, having these contractors in place puts us in the strongest possible position to deliver this transformational scheme and deliver the benefits we know it can.
“The scheme will not only unlock congestion along this vital A303 route, but also conserve and enhance the Outstanding Universal Value of the World Heritage Site.
“Our Delivery Assurance Partner will help us to successfully coordinate and oversee the development of the scheme moving forward. This collaborative team will continue to work with local stakeholders, heritage bodies and local communities to deliver a successful and exceptional project for the area.”
Costain managing director of transportation Sue Kershaw also emphasised the benefits of the scheme.
“This scheme will bring enormous benefits to people using the A303 and those living in the local area, unlocking the regional economy and safeguarding the much-loved Stonehenge World Heritage site and surrounding environment," she said.
“This award recognises our ability to apply our construction expertise to the delivery assurance partner role and we’re delighted that together we are creating connected, sustainable infrastructure that helps people and the planet to thrive.”
Mott MacDonald transportation managing director Ken Norbury added: “We have assembled a world class multi-disciplinary team to support this vital upgrade project.
“We’re proud to be chosen alongside Costain and look forward to working collaboratively with the project team on an outstanding scheme that will improve peoples’ lives, enhance the World Heritage Site and its surrounding environment, and one which the country will be proud of.”
The main works contract covers the construction of the proposed tunnel’s civil, structural, mechanical, electrical and technology components. This includes the tunnel boring machine, along with the approach roadworks and structures and the environmental components of the five-year construction phase.
Opponents of the scheme have suggested that a longer tunnel would help avoid damaging the historic site.
However in documents submitted to the Planning Inspectorate January, National Highways said its position regarding a bored tunnel extension "remains unchanged" and "this option should be excluded from further development".
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