douro

SUBJECT AREA: Civil engineering

[br]

[br]

[br]

During his long life Eiffel, together with a number of architects, was responsible for the design and construction of a wide variety of bridges, viaducts, harbour installations, exhibition halls, galleries and department stores; he set up his own firm in 1867 to handle such construction. Of particular note were his great arched bridges, such as the 530 ft (162 m) span arch over the River Douro at Oporto in Portugal (1877–9) and the 550 ft (168 m) span of the Pont de Garabit over the Truyère in France (1880–4). He was responsible in 1884 for the protective iron-work for the Statue of Liberty in New York and, a year later, for the great dome over the Nice Observatory. In 1876 he had collaborated with Boileau to build the Bon Marché department store in Paris. The predominant material for all these structures was iron, and, in some cases glass was important. The famous Eiffel Tower in Paris is entirely of wrought iron, and the legs are supported on masonry piers that are each set into concrete beneath the ground. The idea of the tower was first conceived in 1884 by Maurice Koechlin and Emile Nougier, and Eiffel won a competition for the commission to built the structure. His imaginative and practical scheme was for a strong lightweight construction 984 ft (300 m) high, with its 12,000 sections to be prefabricated and riveted together largely before erection; the open, perforated design reduced the problems of wind resistance. The tower was constructed on schedule by 1889 to commemorate the centenary of the outbreak of the French Revolution and was the tallest structure in the world until the erection of the Empire State Building in New York in 1930–2.

[br]