Civil Engineering heritage: Scotland - Lowlands and Borders
Date 2007
Event ID 588944
Category Descriptive Accounts
Type Publication Account
Permalink http://canmore.org.uk/event/588944
This is a rare operational example of an early wrought-iron chain-bar suspension bridge. It was made and erected over the Teviot in ca.1835 by chain manufacturer Capt. S. Brown, RN. The span is 186 ft and the timber deck almost 9 ft wide at the suspension pillars. The bridge has double chains at each side of the deck consisting of 10 ft by 2 in. diameter rods with hand-forged eyes and short interconnecting links. The chains are suspended from pairs of ashlar pylons at each end of the bridge. With a sag–span ratio of about 1:14 the chains have amore efficient curvature in terms of their load bearing capacity than Brown adopted at Union Bridge in 1820. A comparison between Union and Kalemouth bridges demonstrates the evolution of Brown’s practice. Other improvements on Union Bridge at Kalemouth were the cross bolting of each pair of chains and the provision against oscillation by means of robust timber lattice parapets. The masonry of the bridge was the work of William Mather, Kalemouth. In 1845 the toll for a pedestrian was a halfpenny, for a horse and cart three pence, and for a chaise one shilling.
In 1987 the bridge was tastefully reconditioned by Borders Regional Council. The timber was renewed, the pylons were refurbished and the pins and short interconnecting main chain links were replaced using spheroidal graphite iron. In 1990 new cable anchorages were installed.
R Paxton and J Shipway 2007
Reproduced from 'Civil Engineering Heritage: Scotland - Lowlands and Borders' with kind permission from Thoomas Telford Publishers.
