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Tunnelling solutions sought as A303 plans reach cash limit

A303 stonehenge

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.

Aecom is developing initial designs with partners Mouchel and Mace. Around 450 scheduled monuments sit within 25km of the route, which passes underneath the Stonehenge World Heritage Site.

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.”

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Readers' comments (1)

  • Philip Alexander

    It's a wonderful "Yes Minister" ploy to announce that you are going ahead with a really popularly supported scheme knowing full well that you're going to pull the plug down the line due to "affordability issues". I'd laugh if it wasn't so tragic. Halcrow took the scheme through Public Inquiry in 2002 and it was approved with minor modifications to the tunnel length and orders could have been produced then and it would have been built and open for the last 10 years by now. Instead, DfT decided that it was too expensive at about £700, which was a vastly inflated figure by the ECI contractors BB/Costain JV in order to cover contingencies. How the cost estimate has now got to £1.6billion is a mystery, but just goes to show how wrong (low) the cost estimate for HS2 is.

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