Thursday, 11 April 2013
Friday, 23 September 2011
The exhibition describes the early development of chain suspension bridges, with particular focus on the innovations of Scotsman Thomas Telford and the London-born engineer Captain Sir Samuel Brown RN.
Capt Samuel Brown was the designer of the Union Chain Bridge which is located just 250 metres from the honey farm and after which the honey farm is named. Today it survives as the oldest chain suspension bridge in the world. But, as this fascinating exhibition describes, there were many other bridges designed and constructed during the nineteenth century which were to rival Brown’s creation.
On reading the exhibition and examining the etchings and photographs, one gets the impression of a fervour for suspension bridge building during the 1800s. We are told that this came about because of innovations in the production of chains, pioneered by Samuel Brown as an alternative for hempen rigging for ships. It is interesting to learn how many bridges and piers were built, but then failed, and how some were proposed but never happened. We are told that Brunel never saw the completion of his Clifton suspension bridge and that at one time a chain bridge was proposed over the Firth of Forth.
What comes across most compellingly is how chain suspension bridges and piers provided beauty in the landscape, so much so that they were depicted by the Victorian artists Naysmith, Tuner and Constable. For the engineers who designed them, the emphasis on grace and beauty seemed to equal the need for strength and durability.
The honey farm is grateful to Steve Jones for producing the exhibition and for bringing it here to the honey farm. We are also grateful to the sponsors of the exhibition which are The Institution of Civil Engineers North East, Berwick History Society, Horncliffe Parish Council and Berwick Rotary Club.
Admission to the exhibition is free, and once you have learnt about chain bridges you can then walk or drive over one!
Wednesday, 19 May 2010
Wednesday, 22 July 2009
Saturday, 21 March 2009
It will be great once the hole is fixed as attention can turn back to the bridge, which at the moment is covered in weeds and has worsening rust. Visit it today if you can!
Thursday, 8 January 2009
Wednesday, 10 December 2008
The Union Chain Bridge spans the River Tweed between Horncliffe, Northumberland, England and Fishwick, Borders, Scotland. When it opened in 1820 it was the longest wrought iron suspension bridge in the world with a span of 137 metres (449 ft), and the first vehicular bridge of its type in the United Kingdom.
Although work started on the Menai Suspension Bridge first, Union Bridge was completed earlier. Today it is the oldest suspension bridge still carrying road traffic. It lies on Sustrans Route 1 and the Pennine Cycleway.
The bridge has been maintained by the Tweed Bridges Trust, since the abolition of turnpike tolls in 1883. It is a Grade I listed building and Scheduled Ancient Monument.
Before the opening of the Union Bridge, crossing the river at this point involved an eleven-mile round trip via Berwick-upon-Tweed downstream or a twenty mile trip via Coldstream upstream. (Ladykirk and Norham Bridge did not open until 1888.)
In addition to the 1902 addition of cables, the bridge has been strengthened and refurbishment on many occasions. The bridge deck was substantially renewed in 1871, and again in 1974, with the chains reinforced at intervals throughout its life.
The bridge was closed to motor vehicles for several months during 2007. A newspaper report available online indicates that the closure happened shortly before 12th April 2007 and was due to one of the bridge hangers breaking. The affected hanger has temporarily been replaced with threaded bar to allow the bridge to reopen to motor vehicles. This losure led to the formation of the Project 2020 group.
In December 2008 the bridge was closed to traffic as a result of a landslide.
The bridge's longevity may owe something to the fact that it was designed by a Royal Navy officer, Captain Samuel Brown. Brown's first design for the bridge was prepared in 1817, and reviewed by the eminent civil engineer John Rennie. Brown had built an experimental suspension bridge with a span of 110 ft, which impressed Rennie. Nonetheless, Rennie asked for changes to the design of the stone abutments and towers.
Brown would have been familiar with the fact that a wooden sailing ship is not totally rigid and designed the bridge on the same basis. Originally the deck was supported by three chains of iron bar links on each side. In 1902 a pair of wire rope cables was added. The decking is of timber and the whole structure is designed to flex slightly under load. Standing on it when a vehicle crosses is reminiscent of being on a ship. For this reason, traffic is now limited to one vehicle on the bridge at any one time.
The bridge proposal, received consent in July 1819 using an Act of Parliament that had been passed in 1802, and construction began 2 August 1819. It opened on 26 July the following year, with an opening ceremony attended by Robert Stephenson among others. Captain Brown tested the bridge in a curricle towing twelve carts, before a crowd of about 700 spectators crossed. The final cost was GB£6,449.