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Civil Engineering heritage: Scotland - Lowlands and Borders

Date 2007

Event ID 610162

Category Descriptive Accounts

Type Publication Account

Permalink http://canmore.org.uk/event/610162

Although a high-level road bridge crossing of the Tay was considered as early as 1929, it was not until March 1963 that construction began on the present bridge which was opened to traffic in August 1966. It was then the longest river crossing of any road bridge in Britain, obviating a 50-mile detour.

The 7365 ft long bridge has 42 spans (31 of which are 180 ft span) with a deck rising from 32 ft above sea level at Dundee to 125 ft in Fife – a gradient of 1 in 81. To reduce the cost of construction the line chosen for the bridge had its north landfall at the old tidal harbour in Dundee, which was infilled and the site used as a fabrication yard by the bridge contractors.

Concrete foundations support twin columns of developing parabolic shape. These were founded on bedrock where the water was shallow and, in deeper water, carried on pile groups driven to the bedrock. The columns support steel-plate box girders 12 ft wide by 10 ft deep with a composite top flange of concrete forming the roadway. The girders range from 10 to 20 ft deep over the navigation channel. They were fabricated in the construction yard at Dundee, and then rolled into position along a service bridge at low level before being lifted and positioned on the columns.

These beams, each weighing 200 tons, were fabricated of steel plate and stiffened internally to give them a maintenance- free exterior profile. They act compositely with the concrete deck of the roadway to form T-beams which support, along their inner edge, precast concrete units that form both a central duct for services and a pedestrian footpath. Overall, 140 000 tons of concrete and 12 750 tons of steel were used. Each carriageway is 22 ft wide and the central footway 10 ft.

The cost of the bridge and its approaches, excluding land and interest charges, was £4.8 million. It was designed by W. A. Fairhurst & Partners. The main contractor was Duncan Logan (Contractors) Ltd. The box girders were fabricated by the Caledon Shipbuilding and Engineering Co. Ltd, Dundee, with Sir William Arrol & Co. Ltd, Glasgow. These firms were subcontractors to Dorman Long (Bridge & Engineering) Ltd, who had the contract for the steelwork and were responsible for the steelwork erection.

Paxton and Shipway 2007

Reproduced from 'Civil Engineering heritage: Scotland - Lowlands and Borders' with kind permission from Thomas Telford Publishers.

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