Eiffel’s masterpiece in bridge building (but with a little help from Léon).
The Garabit viaduct is a French railway viaduct, allowing the crossing of the Truyère gorges. It is located in the Cantal department in the Auvergne-Rhône-Alpes region. The viaduct was designed by the engineer Léon Boyer, who entrusted its completion and construction to Gustave Eiffel and his company.
Construction began in January 1880, and the viaduct was commissioned on 10 December 1888. This ambitious metal structure reaches 122 m above the river and was the highest viaduct in the world of his time.
The Garabit viaduct consists of a 565 m long metal deck resting on five wrought iron pillars of varying heights, 10 spans and 3 decks. The three spans above the lowest part of the valley form the arch with a span of 165 m and a height of 52 m. The steel section is framed by two masonry access viaducts to the north and south, 46 m and 71 m respectively.
For this crossing, it was impossible to use a suspension bridge because of the risk of oscillations, and it was impossible at the time to envisage pillars over 65 m high. Léon Boyer was inspired by the example of the Maria Pia viaduct over the Douro (Porto).
It took approx. 3,250 tons of wrought iron and 678,768 rivets to build the structure. Most of the rivets were already installed at the factory, in Levallois-Perret, to prefabricate large components which were then sent to the final assembly site. This is exactly the same technology that was to be used for the Eiffel Tower.
About the Author:
Bruno Dursin – Managing Director at Believe in Steel. Bruno has more than 30 years of experience in promoting steel & steel solutions. His clients benefit from his extensive network within the building industry.