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Dunkeld Bridge
River Tay, Dunkeld, Perth and Kinross, Scotland, UK
Dunkeld Bridge
associated engineer
Thomas Telford
date  1804/5 - 7th November 1808, opened 29th March 1809
era  Georgian  |  category  Bridge  |  reference  NO025424
ICE reference number  HEW 149
photo  © Derek Menzies and licensed for reuse under this Creative Commons Licence
Dunkeld Bridge over the River Tay is the largest Scottish bridge by engineer Thomas Telford (1757-1834). For more than 160 years the seven-arch masonry structure carried the main road between Perth and Inverness, and it's still in use for local traffic. It one of the early bridges in Telford's Great Glen scheme.
Timber bridges were constructed over the River Tay at Dunkeld from at least the 16th century onwards, but were usually demolished by the river in spate. Until the 19th century, and Telford’s extensive network of Highland roads and bridges, the only other means of crossing here was by ferry.
Dunkeld Bridge is Gothic in style, with modest embellishments. It follows Telford's design philosophy that the spans of multi-arch bridges should increase slightly towards the centre, and that the roadway parapet between abutments should be an arc of a great circle.
Construction began in 1804 or 1805. A site was chosen where the width and shallowness of the river allowed the bridge to be erected in two halves. Each half was built in a dry channel, with the river diverted to the other side. Sandstone for the dressed masonry was quarried at Gellyburn (NO093389), about 10km south east of Dunkeld.
The bridge is about 209m long, and its seven segmental arches span 6.1m, 22.6m, 25.6m, 27.4m, 25.6m, 22.6m and 6.1m. The two flanking arches are on the banks. Inside the superstructure, the space between the arch spandrels is mostly hollow, and given rigidity by longitudinal walls constructed on timber rafts. Telford used this technique for large masonry spans as it reduces loading on the foundations and enables inspection of the internal workmanship.
The masonry piers feature triangular cutwaters surmounted by semicircular masonry towers rising to parapet level where they form pedestrian refuges along the roadway. The carriageway — roadway and footpaths — is 8.7m wide and around 16.5m above water level at the centre span.
The government provided a grant of £7,500, though the majority of the construction cost was met by the landowner, John Murray (1755-1830, 4th Duke of Atholl). The total expenditure is quoted variously as £29,361, "above £30,000" and around £40,000. The contractor and stonemason was John Simpson (1755-1815), who worked regularly with Telford and was described by him as "a treasure of talents and integrity".
Dunkeld Bridge was completed on 7th November 1808, and opened on 29th March 1809. Like the ferries, you had to pay to use it. Tolls to recoup the construction cost were collected from a toll house (NO026423) at the southern abutment. The citizens of Dunkeld resented the toll and their objections led to riots in 1868. The toll was abolished in 1879, when the bridge was taken over by the then county roads authority (Perthshire County Council).
In October 1971, the bridge was Category A listed in and its toll house Category B listed.
Up until 1977, the bridge carried the A9 Perth to Inverness road. In 1976-7, north of the town, a new bridge (NO004438) was constructed, 225m long with three spans supported on twin steel girders. Telford's bridge now carries the A923 and serves mainly local traffic.
On 21st May 2009, John Murray (1929-2012, 11th Duke of Atholl) unveiled a plaque on Dunkeld Bridge to commemorate its bicentenary.
Contractor: John Simpson
Research: ECPK
bibliography
http://portal.historicenvironment.scot
https://canmore.org.uk
www.ice.org
reference sources   CEH SLBBDCE1Smiles2
Location

Dunkeld Bridge