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The Patterson Viaduct was built by the Baltimore and Ohio Railroad (B&O) as part of its Old Main Line during May to December 1829. The viaduct spanned the Patapsco River at Ilchester, Maryland. It was heavily damaged by a flood in 1866 and subsequently replaced with other structures. ==History and design== The viaduct was constructed during the first building phase of the railroad, which extended from Baltimore, Maryland, to Ellicott's Mills. The Patterson, the third bridge built for the B&O, was similar in construction to the company's first bridge, the nearby Carrollton Viaduct and was named for B&O director William Patterson. It was designed by Caspar Wever and built under the supervision of John McCartney, one of Wever's assistants. (McCartney's good work on the Patterson Viaduct was later rewarded with the contract to build the 1833-35 Thomas Viaduct.) The bridge was constructed of granite blocks and was about long, rising about above its foundations. It had four graduated arches: two of chord length each and two of chord length each. The smaller arches allowed the passage of two county roadways, one on each side of the river. The exterior surfaces of the granite blocks were undressed, or rusticated. Patterson ceremonially opened the viaduct on December 4, 1829. In 1830, The viaduct was part of the route used by the B&O's first horse-drawn carriage train to Ellicott's Mills. The viaduct was almost totally destroyed in an 1868 flood. A single-span Bollman Truss built into the west abutment in 1869 incorporated the original roadway arch and upstream wing wall. The Bollman design was supplanted by another bridge before the railroad was realigned about upstream in 1902–03 with the opening of the Ilchester Tunnel. Today, all that remains at the original crossing is the single masonry roadway arch of the 1829 construction on the west bank and the stone abutment on the east bank, just south of the present railroad bridge. In 2006, a cable-stayed footbridge, with a design that echoes a Bollman Bridge, was added atop the abutments. The Patterson Viaduct Ruins were listed on the National Register of Historic Places on June 3, 1976. 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「Patterson Viaduct」の詳細全文を読む スポンサード リンク
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