Tallest iron structure

The tallest iron structure is the Eiffel Tower, in Paris, France, which is 300 m (984 ft 3 in) high. At the time of its inauguration on 31 March 1889, a few weeks ahead of the opening of the Paris Exposition Universelle, the tower was the tallest man-made structure in the world, a title it would hold until the completion of the 318-m (1,046-ft) steel-and-brick Chrysler Building in New York City, USA, on 27 May 1931.

The tower was designed at the Compagnie des Etablissements Eiffel by structural engineers Maurice Koechlin and Émile Nouguier, with assistance from architect Stephen Sauvestre (all France). It was submitted to the planning committee for the 1889 Exposition Universelle – a world’s fair that was being planned to mark the centennial of the French Revolution – as a potential centrepiece for the exhibition site.

Surprisingly, for a structure that is now such an iconic part of the Paris skyline, it was strongly opposed by many influential Parisians and represented a radical design for its time, with little in the way of decorative embellishments to cover its bare structure. It was planned to only remain on the site for a few years, but by the time it was scheduled to come down the people of Paris campaigned to keep it in place.

The tower was made from 7,000 tonnes (7,716 US-tons) of “puddled iron” – a form of low-carbon wrought iron whose structural use had been pioneered by Gustave Eiffel in the 1870s. This material had around three times the tensile strength of the cast iron used in early metal structures, but only around half the strength of modern structural steel. Wrought iron was already becoming obsolete as a building material by 1889, and by 1900 had been almost completely replaced by rolled steel.