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The Union Bridge (also Union Chain Suspension Bridge and Union Chain Bridge) is a suspension bridge that spans the River Tweed between Horncliffe, Northumberland, England and Fishwick, Berwickshire, Scotland. It forms one route crossing the Anglo-Scottish border. When it opened in 1820 it was the longest wrought iron suspension bridge in the world with a span of , 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. With the abolition of turnpike tolls in 1883, maintenance of the bridge passed to the Tweed Bridges Trust. When the Trust was wound up, the bridge became the responsibility of Scottish Borders Council and Northumberland County Council and it is now maintained by the County Council.〔(Friends of the Union Chain Bridge website - History )〕 The bridge is a Category A listed building in Scotland and a Grade I listed building in England. It is a Scheduled Ancient Monument in both countries. Before the opening of the Union Bridge, crossing the river at this point involved an round trip via Berwick-upon-Tweed downstream or a trip via Coldstream upstream. (Ladykirk and Norham Bridge did not open until 1888.) == Design and construction== The bridge 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 , 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. Traffic is now limited to one vehicle on the bridge at a time. The bridge proposal received consent in July 1819, using an Act of Parliament that had been passed in 1802, and construction began on 2 August 1819. It opened on 26 July the following year, with an opening ceremony attended by the celebrated civil engineer Robert Stevenson 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 £6,449. Until 1885, tolls were charged for crossing the bridge; the toll cottage, being at the English end, was demolished in 1955. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Union Bridge (Tweed)」の詳細全文を読む スポンサード リンク
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