Forth Bridge: £4.2bn cable-stayed structure approved

A new structure is to be built as the old bridge struggles to cope with number of vehicles.

11:00 20 Dec 2007
By James Atkinson

Scottish ministers yesterday approved a decision to build a replacement Forth road bridge, which will take the form a cable-stayed bridge costing up to £4.2bn.

The new bridge will run from the northern shore from just west of the existing road bridge to a point west of South Queensferry on the Edinburgh side of the Forth.

The bridge will consist of a dual two-lane carriageway with hard shoulders to provide an area for breakdowns to pull over. Provision will be made for pedestrians and cyclists. The bridge deck may be widened to accommodate two lane multi-modal systems for public transport.

The announcement was made by finance and sustainable growth secretary John Swinney, who said that because of the deteriorating state of the existing bridge, “doing nothing is not an option”. The existing bridge, built in 1964, faces closure to heavy vehicles in 2013 and all vehicles by 2019.

The Scottish government will now move forward with the legislative and procurement options for delivery of the scheme. Further announcements are expected in 2008.

Work is continuing on the procurement options, including consideration of the appropriate transfer of risk to the private sector. The government is against tolling.

The outline programme envisages a submission for authorisation in 2009, a procurement competition in 2010 and the appointment of a contractor in 2011.

The Scottish government looked at four options: a suspension bridge; a cable-stayed bridge; a bored tunnel; and an immersed tunnel.

In appraising each option consideration was given to: impact on the environment; operating restrictions; operational risk; cost; cost risk; and time to construct.

While the bored tunnel option performed best on environmental grounds, the bridge options performed better against the operating restrictions and operating risk criteria. The ability to add multi-modal public transport options also favoured the bridges.

The cable-stayed bridge performed best against the cost criteria.
Cable-stayed bridge: £3.25bn-£4.22bn
Suspension bridge: £3.62bn-£4.70bn
Bored tunnel: £5.12bn-£6.60bn
Immersed tube tunnel: £4.77bn-£6.19bn

The scheme is controversial with Friends of the Earth and some Edinburgh councillors claiming that the new bridge will double traffic levels in an already congested area.