Dryburgh Suspension Bridge

Dryburgh Bridge is a pedestrian bridge over the Tweed in Scotland, which connects the town of St. Boswells in the Scottish Borders with the village of Dryburgh near Dryburgh Abbey. The current bridge, the third bridge at this location.

First Bridge ( 1817)

The first Dryburgh Bridge was built in 1817 by the brothers John and William Smith on behalf of the Earl of Buchan as a replacement for the long standing ferry. She had a wingspan of 79 m (260 ft) and was 1.22 (4 ft) wide. She was authorized by its owners for pedestrians and horses run.

The built in less than five months bridge was a chain bridge in the nature of the subsequent cable-stayed bridges with inclined of the four pylons for the bridge deck poles tensioned chain that led from the start in the use to severe vibrations. This amused three young people who managed to step up the vibrations until one of the longest bars in her eye burst. In a violent storm in January 1818, the vibrations were so strong that the longest chain link broke again, puts the bridge deck in heavy horizontal and vertical vibrations and blown down, and the bridge was destroyed. Investigations showed that the forged eyes had held, but the only curved and provided with a thimble eye on the other end of the rods were broken.

The collapse of the bridge attracted considerable stir among professionals. They took it for a long time interval of further experiments with oblique chains.

Second Bridge ( 1818)

A little later a new building was constructed over a period of less than three months, now as a chain suspension bridge with vertical hangers. This time, all eyes of the chain stays were forged. The more than 5 m above the river leading bridge deck was stiffened by a strong truss railing and provided with inclined tension string to the opposite bank, which should prevent the movement of the roadway support in strong winds. Robert Stevenson said after their visit, that this bracing would have had no great effect. The two- arranged in the longitudinal direction girder bridge deck was supported on either side by two chains, which consisted of 3 m long rods. The pylons had a height of 8.5 m above the bridge deck. They were stiffened by transverse webs at the tips.

1838 also this bridge was destroyed by a severe storm.

Third Bridge ( 1872)

1872 Construction of the Dryburgh Bridge was built in the form of a slightly wider, wrought iron suspension bridge with dual carrying cables and an iron bridge deck, which is reinforced by lateral iron truss railing and is occupied by a wooden walkway.