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The Manhattan Bridge is a suspension bridge that crosses the East River in New York City, connecting Lower Manhattan at Canal Street with Downtown Brooklyn at the Flatbush Avenue Extension. The main span is long, with the suspension cables being long. The bridge's total length is . This is one of four toll-free bridges spanning the East River; the other three are the Queensboro, Brooklyn, and Williamsburg Bridges. The bridge opened to traffic on December 31, 1909. It was designed by Leon Moisseiff,〔 and is noted for its innovative design. As the first suspension bridge to employ Josef Melan's deflection theory for the stiffening of its deck, it is considered to be the forerunner of modern suspension bridges and this design served as the model for many of the long-span suspension bridges built in the first half of the twentieth century. The Manhattan Bridge was also the first suspension bridge to utilize a Warren truss in its design. ==History and description== The Manhattan Bridge was the last of the three suspension bridges built across the lower East River, following the Brooklyn and Williamsburg bridges. It has four vehicle lanes on the upper level, split between two roadways. The lower level has three lanes, four subway tracks, a walkway and a bikeway. The upper level, originally used for streetcars, has two lanes in each direction, and the lower level is one-way and has three lanes in peak direction. The bridge once carried New York State Route 27 and later was planned to carry Interstate 478. The original pedestrian walkway on the south side of the bridge was reopened after forty years in June 2001. It was also used by bicycles until late summer 2004, when a dedicated bicycle path was opened on the north side of the bridge, again in 2007 while the bike lane was used for truck access during repairs to the lower motor roadway, and for a third time in 2011, when ongoing construction on the north side of the bridge necessitated narrow shelters, narrowing the path to make it unsafe for cycling. To celebrate the bridge's centennial anniversary, a series of events and exhibits were organized by the New York City Bridge Centennial Commission in October 2009. These included a ceremonial parade across the Manhattan Bridge on the morning of October 4 and a fireworks display in the evening.〔(【引用サイトリンク】title=Manhattan Bridge Centennial Celebration Events and Exhibits )〕 In 2009, the bridge was also designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers.〔(【引用サイトリンク】title=Manhattan Bridge )〕 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「Manhattan Bridge」の詳細全文を読む スポンサード リンク
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