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}} The Waldo–Hancock Bridge was the first long-span suspension bridge erected in Maine, as well as the first permanent bridge across the Penobscot River below Bangor. The name comes from connecting Waldo and Hancock counties. The bridge was retired in 2006, when the new Penobscot Narrows Bridge was opened just a few yards away, and it was demolished in 2013. The bridge was long with a clear center span of between towers. It had two side spans and carries a wide roadway with two sidewalks. It used stiffening trusses that are deep. Each of the main suspender cables were in diameter, and consisted of 37 strands of 37 wires. The deck was above water level to allow passage of large ships. The total cost of the span was less than $850,000 in 1931 dollars (about $12 million in 2010 dollars), significantly under its allocated budget. ==Construction== David B. Steinman, of Robinson and Steinman, was the designer. The bridge was fabricated by American Bridge Company (superstructure) and Merritt-Chapman & Scott (substructure). Technologically, the Waldo–Hancock Bridge represented a number of firsts. It was one of the first two bridges in the U.S. (along with the St. Johns Bridge in Portland, Oregon, completed in June, 1931) to employ Robinson and Steinman’s prestressed twisted wire strand cables, which were first used on the 1929 Grand Mère Suspension Bridge over the Saint-Maurice River in Quebec. The prefabrication and prestressing of the cables decreased the number of field adjustments required, saving considerable time, effort, and money. As an additional experiment in efficiency, the Waldo–Hancock cables were marked prior to construction, ensuring proper setting. This method had never been used before and proved successful in this instance. These innovations, invented and pioneered by Steinman, were a significant step forward for builders of suspension bridges. The Waldo–Hancock was also the first bridge to make use of the Vierendeel truss in its two towers, giving it an effect that Steinman called “artistic, emphasizing horizontal and vertical lines.” This attractive and effective truss design was later used in a number of important bridges, including the Triborough Bridge and Golden Gate Bridge. The Waldo–Hancock Bridge was noted at the time for its economy of design and construction. It cost far less than had been appropriated by the State Highway Commission, which enabled the construction of a second bridge between Verona Island and Bucksport. When opened in 1931 the bridge collected tolls used to retire the bonds issued to finance its construction. All tolls were lifted twenty-two years later on October 31, 1953, however, when those original construction bonds were paid off. 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「Waldo–Hancock Bridge」の詳細全文を読む スポンサード リンク
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