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Structure Steel Design's Handbook 2009 part 18

Tham khảo tài liệu 'structure steel design's handbook 2009 part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | SECTION 14 ARCH BRIDGES Arthur W. Hedgren Jr. P.E. Senior Vice President HDR Engineering Inc. Pittsburgh Pennsylvania Basic principles of arch construction have been known and used successfully for centuries. Magnificent stone arches constructed under the direction of engineers of the ancient Roman Empire are still in service after 2000 years as supports for aqueducts or highways. One of the finest examples is the Pont du Gard built as part of the water-supply system for the city of Nĩmes France. Stone was the principal material for arches until about two centuries ago. In 1779 the first metal arch bridge was built. Constructed of cast iron it carried vehicles over the valley of the Severn River at Coalbrookedale England. The bridge is still in service but now is restricted to pedestrian traffic. Subsequently many notable iron or steel arches were built. Included was Eads Bridge with three tubular steel arch spans 502 520 and 502 ft over the Mississippi River at St. Louis. Though completed in 1874 it now carries large daily volumes of heavy highway traffic. Until 1900 stone continued as a strong competitor of iron and steel. After 1900 concrete became the principal competitor of steel for shorter-span arch bridges. Development of structural steels made it feasible to construct long-span arches economically. The 1675-ft Bayonne Bridge between Bayonne N.J. and Staten Island N.Y. was completed in 1931. The 1000-ft Lewiston-Queenston Bridge over the Niagara River on the United States-Canadian border was put into service in 1962. Availability of more high-strength steels and improved fabrication techniques expanded the feasibility of steel arches for long spans. Examples include the 1255-ft-span Fremont Bridge in Portland Ore. finished in 1973 and the 1700-ft-span New River Gorge Bridge near Fayetteville W. Va. opened in 1977. Nearly all the steel arches that have been built lie in vertical planes. Accordingly this section discusses design principles for such arches. A