Civil Engineering heritage: Scotland - Lowlands and Borders
Date 2007
Event ID 588984
Category Descriptive Accounts
Type Publication Account
Permalink http://canmore.org.uk/event/588984
Drygrange, or ‘Fly Boat’ Bridge as it used to be known referring to an earlier ferry, is a masonry arch bridge
constructed as a turnpike road improvement in 1779–80 with a central span of 105 ft and two side spans of 55 ft. The rise of the main arch is 34 ft and its arch ring is only 212 ft thick at the crown. The bridge was designed and constructed by Stevens, who applied state-of-the-art practice, including three longitudinal cavities in each spandrel to reduce weight. Its pier foundations are of large hewn stones joined by iron cramps and laid on rock. The cutwaters are of the curved and pointed shape preferred by French engineers but very new to Britain in 1780. The bridge is believed to have been Stevens’ most daring design. For many years, until bypassed in 1974, it carried the A68 trunk road.
R Paxton and J Shipway 2007
Reproduced from 'Civil Engineering Scotland: Scotland - Lowlands and Borders' with kind permission from Thomas Telford Publishers.
