Cost-saving tunnelling innovations are being sought for the A303 Stonehenge scheme, which is already reaching its affordability limit.
Highways England project director for the A303 Stonehenge scheme Derek Parody has said that the scheme is already straining against its £1.6bn affordability limit set by government.
“We’re already reaching as much as government is prepared to spend on the scheme, and the only way we can create headroom from here on in is to actually value engineer some of the components out of it, but as you can see from the nature of the scheme it’s really quite difficult to value engineer anything because the bulk of the cost of the scheme is the tunnel,” he said.
“So we’re looking from some good innovation from some good tunnelling people to come up with good solutions.”
A procurement strategy for the scheme is currently being prepared with government leaning towards a private funding model, according to Parody. If that happens, the contract will likely be a design, build, finance and maintain contract without operating responsibilities.
“There is a long discussion taking place about risk transfer and what’s appropriate and what’s not appropriate, given the sensitivities of the scheme and everything that goes with it,” said Parody.
In September government announced the preferred route for the scheme. A 2.9km long twin-bore, dual carriageway tunnel will carry traffic past Stonehenge. At the moment a single carriageway road passes within 165m of the World Heritage Site, leading to congestion as motorists slow to look.
A new junction will be built between the A303 and the A345, as well as a bypass to the north of Winterbourne Stoke. Next September a development consent order (DCO) will be applied for and if successful, construction is due to start in 2021.
More than 60 proposals for road alterations at Stonehenge have been put forward in the past but stumbled due to affordability concerns, among other reasons.
A spokesperson for the DfT said: “The government is committed to upgrading the A303 at Stonehenge as part of its Road Investment Strategy. The financing arrangements for the project are currently under review, including assessing whether private finance can play a role.”