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}} The Wheeling Suspension Bridge is a suspension bridge spanning the main channel of the Ohio River at Wheeling, West Virginia. It was the largest suspension bridge in the world from 1849 until 1851. It was designed by Charles Ellet Jr., who also worked on the Niagara Falls Suspension Bridge. The Wheeling bridge was the first to span the Ohio River, and was an important link on the National Road. The main span is from tower to tower. The east tower rests on the Wheeling shore, while the west tower is on Wheeling Island. The east tower is above the low-water level of the river, or from the base of the masonry. The west tower is above low water, with of masonry. The Wheeling Suspension Bridge was designated a National Historic Landmark on May 15, 1975.〔 It is located in the Wheeling Island Historic District.〔 ==History== A charter was granted to the Wheeling and Belmont Bridge Company in 1816 to construct a bridge to extend the Cumberland Pike, which was to be completed in 1818, to Ohio. After a number of delays, a new bridge charter was obtained in 1847. Charles Ellet and John A. Roebling were invited to submit designs and estimates for a bridge over the east channel of the river to Wheeling Island.〔 In doing so, the design was set as a suspension bridge, as Ellet and Roebling were the foremost authorities on the topic. Ellet received the contract award in 1847 and began the same year. The bridge was completed in 1849.〔 On May 17, 1854 a strong windstorm destroyed the deck of the bridge through torsional movement and vertical undulations that rose almost as high as the towers.〔 Ellet rebuilt it, followed by improvements in 1859 by Ellett's partner William McComas, and in 1874 by William Hildenbrand. A 1953 report indicates that the suspension cables are either original or the work of the 1860 reconstruction. The deck stiffening truss is believed to be from the same period. Auxiliary stay cables were added in 1871-72 to a design by Washington Roebling and Hildebrand. The deck was completely rebuilt in 1956, when the road was widened from to and the sidewalks were correspondingly narrowed. The road and sidewalk were reconstructed with an open steel grating that reduces wind resistance, and rests on lightened steel floor beams.〔 In the early 1980s, the West Virginia Division of Highways restored the bridge.〔 The bridge remains in active service. The bridge spans a distance of 1,010 feet (308 m) across the Ohio River and allows barges to pass underneath. It remains the oldest vehicular suspension bridge in the United States still in use and is listed as both a National Historic Landmark and Historic Civil Engineering Landmark. On February 17, 2011, a vehicle driving at high speed lost control and crashed into the sidewalk panels on the bridge. The damage to the bridge was enough that it was closed for inspection. The bridge was closed for four to five days so the panels could be fixed, as well as other minor repairs.〔http://wtrf.com/story.cfm?func=viewstory&storyid=94494〕〔http://wtrf.com/story.cfm?func=viewstory&storyid=94563〕 On March 2, 2013, a non-load bearing cable snapped, causing the bridge to be closed until the cable was repaired and detailed inspections were completed 〔http://www.post-gazette.com/stories/local/region/wheeling-suspension-bridge-oldest-of-its-kind-in-use-closed-after-cable-breaks-677855/〕 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「Wheeling Suspension Bridge」の詳細全文を読む スポンサード リンク
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