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Chain Bridge at Falls of Schuylkill was an 1808 iron-chain suspension bridge built across the Schuylkill River, north of Philadelphia, Pennsylvania. Designed by inventor James Finley, it became the model for his later chain suspension bridges. It collapsed in 1816 under a heavy load of snow. ==History== The Chain Bridge had two spans: an eastern one of 200 feet (60.96 m), and a western one of about 100 feet (30.48 m). The bridge's chain cables were carried over paired A-frame wooden towers on its east and west abutments, and a third pair of towers atop a stone pier built in the river. Its chains were made of 1.5-inch-square (3.8 cm) iron bar wrought into links of between 8 and 12 feet (2.44 and 3.66 m) in length. These were used for both the cables and the vertical suspenders. The suspenders were attached to 10-by-5-inch (25.4 cm x 12.7 cm) wooden joists spaced 10 feet (3 m) apart, and covered by a 2.5-inch-thick (6.4 cm) wooden deck that was 18 feet (5.5 m) wide and 306 feet (93.26 m) long.〔''The Portfolio'', p. 449.〕 Although Finley patented his Falls of Schuylkill bridge and publicized it widely, it was not a success. "''Part of the superstructure broke down in September, 1810, while a drove of cattle was crossing it, and in January, 1816, the bridge fell down, occasioned by the great weight of snow which remained on it, and a decayed piece of timber.''"〔Jackson, p. 412.〕 A wooden covered bridge was built upon the Chain Bridge's abutments in 1818, but washed away in 1822.〔Jackson, p. 411-12.〕 The Reading Railroad Bridge (1853-56, still in use) crosses the Schuylkill at the approximate location of the Chain 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「Chain Bridge at Falls of Schuylkill」の詳細全文を読む スポンサード リンク
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