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The Frisco Bridge, previously known as the Memphis Bridge, is a cantilevered through truss bridge〔(Bridge Hunter Historic Bridge Page )〕 carrying a rail line across the Mississippi River between West Memphis, Arkansas and Memphis, Tennessee. ==Construction== At the time of the Memphis bridge construction, it was a significant technological challenge and is considered to be chief engineer George S. Morison's crowning achievement. No other bridges had ever been attempted on the Lower Mississippi River. The bridge is built entirely of open-hearth steel, a newly developed material at the time of construction. The structure features a 790-foot main span and two additional 600-foot spans. Its 65-foot height above the water was the highest clearance of any U.S. bridge of that era. The construction of the piers went nearly 100 feet below the water's surface. Though some sources claim two cantilevered roadways were added to the bridge in the 1930s, one on each side,〔(American Society of Civil Engineers: Morison's Memphis Bridge )〕 they probably confuse this bridge with the neighboring Harahan Bridge, which had two cantilevered roadways from 1917 until the Memphis & Arkansas Bridge opened in 1949. Today, the Harahan Bridge still has the metal remains of its cantilevered roadways; the Frisco Bridge does not. However, pedestrians, buggies, and some automobiles used the main deck of the Frisco Bridge before the Harahan Bridge opened (the bridge was closed to such traffic while a train was crossing).〔(Frisco Bridge, Memphis, TN (John A. Weeks III: Highways & Bridges) )〕 Construction for the Kansas City, Fort Scott and Memphis Railway, later acquired by the "Frisco," began in 1888 and was completed May 12, 1892. In the end the project created a bridge that was the farthest south on the Mississippi River, featured the longest span in the United States and cost nearly 3 million dollars.〔Historic American Engineering Record (Library of Congress). (Survey number HAER NE-2 ). p315-380. 1986.〕 A testament to its design and construction, as of 2014 the bridge is still used by BNSF Railway. The bridge is listed as a Historic Civil Engineering Landmark.〔 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「Frisco Bridge」の詳細全文を読む スポンサード リンク
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