Bridges.
The most notable ones in United States history are:
Arch bridges.
St. Louis Bridge across the Mississippi at St. Louis, Mo.; three arches formed of tubes of cast-steel, and built out from the piers without scaffolding: the centre span, 520 feet; the others. 502 feet each; 2,200 tons of steel and 3,400 tons of iron were used in its construction. Built by Col. James B. Eads at a cost of $10,000,000. Begun 1867, and completed July 4. 1874.High Bridge, across the Harlem River, in New York City; built to carry the Croton aqueduct across the river. It consists of thirteen arches, and is 1,460 feet long.
Washington Bridge, across the Harlem River. just north of High Bridge; consists of nine arches, three of granite on the east side, four of granite on the west, and two steel arches spanning the river. This bridge is 2,400 feet long and 80 feet wide; completed in 1888.
Suspension bridges.
Niagara Falls Suspension Bridge, across the gorge, 2 miles below the falls; built by John A. Roebling; length of span between towers, 800 feet; supported by four wire cables, each containing 3,640 No. 9 wires; height of track above the water, 245 feet: carriage-way beneath the track: cost of bridge, $400,000; work begun 1852; first locomotives crossed March 8, 1855.Cincinnati and Covington Suspension Bridge, over the Ohio River. at an elevation of 91 feet above low-water, and with a span of 1,057 feet; built by Roebling, and completed in 1867.
Clifton Suspension Bridge, at Niagara Falls, a short distance below the falls: built for carriages and foot-passengers; has a span of 1,260 feet; begun 1867; completed in 1869; blown down Jan. 10, 1889, and a new structure of iron, hung on steel cables, opened May 7, 1889.
Brooklyn Bridge, a wire cable suspension bridge connecting New York City with Brooklyn; designed by John A. Roebling, and built by his son, W. A. Roebling; carriage-way, 5,989 feet, and including extensions, 6,537 feet; a central span of 1,595 feet, and two side spans of 930 feet each, with a clear headway under the centre of the bridge of 135 feet above high-water; total height of towers above high-water, 278 feet. There are four suspension cables. composed of 5,296 galvanized steel wires, bound together, but not twisted; width of bridge. 85 feet; cost, $15,000,000; bridge begun 1870; opened May 24. 1883.
New East River Bridge (under construction), connecting New York City with Brooklyn: north of the Brooklyn Bridge. The roadway of this bridge is supported by six steel cables passing over steel towers on each side of the river.
North River Bridge (under construction), across the Hudson, between New York City and Hoboken, N. J. In this bridge the towers are to be of steel, 557 feet high. The central span will be 3,110 feet long, and the lowest point of the bridge 150 feet above high-water.
Cantilever bridges.
Niagara Falls Cantilever, over the gorge, a short distance above the old suspension bridge; the first true metal cantilever bridge erected, comprising two cantilevers, 385 feet each in length, extending from the shores to piers, and reaching out over the river, supporting a central girder 120 feet in length; distance between piers. 495 feet; height of bridge, 180 feet above the water; opened Dec. 20, 1883.Kentucky and Indiana Bridge. over the Ohio River, at Louisville; has two cantilever spans of 480 and 483 feet; begun in 1883; completed in 1888.
Poughkeepsie Bridge, crossing the Hudson River at Poughkeepsie; is composed of two cantilever spans on each shore of 523 feet, and a central cantilever span of 521 feet, joined by two ordinary girders of 500 feet span with projecting cantilever ends; work begun 1886; opened in 1888. [403]
Blackwell's Island Bride (under construction), across the East River north of the Brooklyn Bridge. It has four channel piers, 135 feet above high-water. The bridge will be 2 miles in length, with two channel spans of 846 feet each, and one across Blackwell's Island of 613 feet.
Girder and miscellaneous bridges.
Arthur Kill Bridge, between Staten Island and New Jersey, consists of two shore-spans of 150 feet each, covered by fixed trusses, and a draw 500 feet in length; can be opened and closed in two minutes; bridge authorized by act of Congress June 16, 1886; completed at a cost of $450,000, June 13, 1888.Wooden bridge, over the Connecticut at Hanover, with a single arch of 236 feet; erected in 1796.
Potomac Run Bridge, a famous trestle-work 400 feet long and 80 feet high; built in nine days by soldiers of the Army of the Potomac under the supervision of Gen. Herman Haupt. It contained more than 2,000,000 feet of lumber, chiefly round sticks, fresh cut from the neighboring woods; erected May, 1862.
Portage Bridge, over the Genesee River, on the line of the Erie Railroad at Portage, N. Y. An iron truss bridge on iron trestles, built in 1875, to replace the original wooden trestle bridge; completed Aug. 14, 1852, and burned down, May 6, 1875; total length, 800 feet, comprising one span of 180 feet, two of 100 feet, and seven of 50 feet; height, 130 feet above the river; contract let. May 10, 1875; opened for traffic July 31, 1875.
Wrought-iron girder bridge, at Cincinnati, over the Ohio River, with a span of 519 feet; 105 feet above low-water; built in 1877.
Kentucky River Bridge, a trussed girder bridge of iron, on the line of the Cincinnati Southern Railroad; three spans of 375 feet; built without false work; begun Oct. 16, 1876, and completed at a cost of $404,230, Feb. 20, 1877.
