The Dornoch Firth Bridge is a road bridge over the

Dornoch Firth The Dornoch Firth ( gd, Caolas Dhòrnaich, ) is a firth on the east coast of Highland, in northern Scotland. It forms part of the boundary between Ross and Cromarty, to the south, and Sutherland, to the north. The firth is designated as a nationa ...

, carrying traffic between

Tain Tain ( Gaelic: ''Baile Dhubhthaich'') is a royal burgh and parish in the County of Ross, in the Highlands of Scotland. Etymology The name derives from the nearby River Tain, the name of which comes from an Indo-European root meaning 'flow'. The ...

and

Dornoch Dornoch (; gd, Dòrnach ; sco, Dornach) is a town, seaside resort, parish and former royal burgh in the county of Sutherland in the Highlands of Scotland. It lies on the north shore of the Dornoch Firth, near to where it opens into the Moray ...

History

It was built for the

Scottish Office The Scottish Office was a department of the Government of the United Kingdom from 1885 until 1999, exercising a wide range of government functions in relation to Scotland under the control of the Secretary of State for Scotland. Following the e ...

. There had been recent substantial improvements of the A9 between Inverness and Tain, including the cable-stayed

Kessock Bridge The Kessock Bridge ( gd, Drochaid Cheasaig) carries the A9 road (Great Britain), A9 trunk road across the Beauly Firth at Inverness, Scotland. Description The Kessock Bridge is a cable-stayed bridge across the Beauly Firth, an inlet of the Mor ...

at Inverness in 1982. The Dornoch Bridge was to be the final link in the chain. Tenders were open to bid from 1986, and 40 companies showed an interest in the contract.

Ove Arup Sir Ove Nyquist Arup, CBE, MICE, MIStructE, FCIOB (16 April 1895 – 5 February 1988) was an English engineer who founded Arup Group Limited, a multinational corporation that offers engineering, design, planning, project management, and ...

and Crouch Hogg Waterman of Glasgow produced a set of initial design parameters for companies to build. The joint-venture chosen to build the bridge put in a quote for £9.5 million, and won the contract in early 1988. There were proposals that the bridge should be constructed so as to allow the Far North railway line to benefit from the shorter route as well, with the potential for up to 45 minutes to be saved on the journey between

Inverness Inverness (; from the gd, Inbhir Nis , meaning "Mouth of the River Ness"; sco, Innerness) is a city in the Scottish Highlands. It is the administrative centre for The Highland Council and is regarded as the capital of the Highlands. Histori ...

and

Thurso Thurso (pronounced ; sco, Thursa, gd, Inbhir Theòrsa ) is a town and former burgh on the north coast of the Highland council area of Scotland. Situated in the historical County of Caithness, it is the northernmost town on the island of Great ...

Wick Wick most often refers to: * Capillary action ("wicking") ** Candle wick, the cord used in a candle or oil lamp ** Solder wick, a copper-braided wire used to desolder electronic contacts Wick or WICK may also refer to: Places and placenames ...

. However this part of the scheme failed to secure government funding, and so only a road bridge was built.

Design

Each of the 21 spans is about long. The Project Manager was Nigel Beaney of Christiani & Nielsen.

Prestressed concrete Prestressed concrete is a form of concrete used in construction. It is substantially "prestressed" ( compressed) during production, in a manner that strengthens it against tensile forces which will exist when in service. Post-tensioned concreted i ...

rather than steel was chosen as the material to improve the life of the bridge. The design had to be approved by the

Royal Fine Art Commission for Scotland The Royal Fine Art Commission for Scotland was a Scottish public body. It was appointed in 1927 "to enquire into such questions of public amenity or of artistic importance relating to Scotland as may be referred to them by any of our Department ...

Construction

Plaque on the Dornoch Firth Bridge - geograph

It was built by a joint venture of

Christiani & Nielsen Christiani & Nielsen (Thai) Public Company Limited is a construction contractor with major operations in Thailand and Southeast Asia. Originally a Danish company, it is today a listed company majority owned by the GP Group. The company provides ...

. It cost £13.5 million (£ million current value). At the time it was one of the longest bridges in Europe built with the cast-and-push method, or

incremental launch Incremental launch is a method in civil engineering of building a complete Deck (bridge), bridge deck from one abutment of the bridge only, manufacturing the Superstructure#Bridges, superstructure of the bridge by sections to the other side. In c ...

. The bridge deck was built in a temporary factory 20 metres south of the southern end of the bridge. Each section of the bridge was pushed with of hydraulic force over

PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...

bearings on the top of the bridge supports. The launch nose sectionLaunch nose front view
/ref> had a light steel composition to reduce the

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

moment as it was inched over an open span. Each deck section was constructed as around in length – half a span. The concrete used welded mat reinforcement. The pre-stressing of each section had 38

Macalloy McCalls Special Products Ltd is a British manufacturer of steel bar and cable components for tensioned concrete, ground anchors, curtain walling, and steel structures. It operates under the Macalloy brand and claims to be a world leader in th ...

bar tendons of 40 mm thickness. The sections would be cast on a Monday morning and pushed on a Friday, this later being on a Thursday. Each deck section weighed around .

Opening

Aerial view of Tarlogie and the Dornoch Bridge behind - geograph

The bridge was opened by

The Queen Mother ''The'' () is a grammatical Article (grammar), article in English language, English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite ...

on Tuesday, 27 August 1991. It replaced, via a roundabout with the A836 to the south and a road junction with the A949 to the north, the round trip over

Bonar Bridge Bonar Bridge ( gd, Drochaid a' Bhanna, ) is a village on the north bank of the Kyle of Sutherland to the west and the Dornoch Firth to the east in the Parish of Creich in the Highland council area of Scotland. The Kyle of Sutherland ("the Kyle" ...

References

External links

SABRE Roads

Construction
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Video clips

Sailing under the bridge
1991 establishments in Scotland Box girder bridges in the United Kingdom Bridges completed in 1991 Bridges in Highland (council area) Buildings and structures in Sutherland Concrete bridges in the United Kingdom Road bridges in Scotland