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Metal Bridge (1820), site of
River Esk, Cumbria
Metal Bridge (1820), site of
associated engineer
Thomas Telford
date  1820
era  Georgian  |  category  Bridge  |  reference  NY354649
ICE reference number  HEW 970
photo  ICE Library
Near the mouth of the River Esk, where the A74 crosses on its way to Gretna, is the site of a significant cast iron bridge by Thomas Telford. It was replaced in 1916 by a ferro-concrete bridge, possibly by L. G. Mouchel, but in any case also now gone.
Telford's bridge, also known as Esk Bridge, was built as part of the Glasgow to Carlisle road (1815-1823) — or West Coast Great North Road. This project was one of a series of Scottish road projects he undertook for the Highland Roads Commissioners.
The bridge had three cast iron spans. The southern-most span measured 45.7m and the other two 32m each. The cast iron arch ribs for the longer span were 914mm deep, and those for the shorter spans 762mm.
The spandrel panels were cast in the form of crosses. Their lower ends were located in sockets in the arch ribs and upper ends fixed to cast iron beams. Resting on the spandrels were the 25mm-thick deck plates. A cast plate on the bridge carried the inscription, “Thos. Telford Engr” and the date “1820”. The abutments and two river piers were constructed in local stone.
The castings were made in Ruabon in Denbighshire. They may originally have been intended for a site in Wales because the River Esk bridge had an undulating appearance, indicating possibly that the spans had been transposed. Gradients across the bridge varied from 1 in 14 to 1 in 40.
The bridge nearly made it to its centenary year but not quite, as an inspection in 1911 found it to be badly corroded. It was closed to traffic, and its ferro-concrete replacement was approved for construction on 7th May 1913. It's not clear whether the second bridge was designed by the Cumberland County Surveyor & Bridgemaster or by Mouchel himself, but the Mouchel Hennebique ferro-concrete system was used.
Both the concrete bridge and the remains of Telford's abutments were removed in 1970 for the construction of the A74. The casting shown in the photo is preserved at Tullie House Museum, Carlisle. The name ‘Metal Bridge’ is preserved in the name of an inn near the bridge site.
Telford's cast iron bridge stood for 95 years, admirably coping with a river at this point as wide as the Thames at London, and with a tidal range of 5m.
Research: PD and AJD
bibliography
“The Story of Telford: The Rise of Civil Engineering”
by Sir Alexander Gibb, Alexander MacIehose & Co, 1935
“Esk Bridge” by Cumbria County Council Highways & Bridges Department
commemorative pamphlet ,1916
Minutes of the Highways Committee, Cumberland County Council, 1913
“Mouchel-Hennebique Ferro-Concrete”, Mouchel, London, 1921
reference sources   BDCE1Smiles2
Location

Metal Bridge (1820), site of