Ferdinand Arnodin
Ferdinand Joseph Arnodin (9 October 1845 – 24 April 1924) was a French engineer and industrialist, born in Sainte-Foy-lès-Lyon, Rhône. He died in Châteauneuf-sur-Loire.
1874 Arnodin invented a new type of twisted cable intended for suspension bridges, with each layer twisted in opposite directions. It was first used in 1879 on the Pont de Saint-Ilpize sur l'Allier. Photo of bridge here.
One 1889 source[1] gave the following information about the 'alternately twisted' cables:-
'... all the wires in the same cable, except the central one, have the same length, and when the cable is stretched all the wires are equally elongated. This is a property which belongs only to cables with straight wires, and to those which are alternately twisted. The tensions of the different wires produced by the elongation of cables twisted in the ordinary way, as in American cables have very different values. These cables invented by M. Arnodin may be called alternately twisted cables.
'The alternately twisted cables have a much greater flexibility, which will be easily understood when we consider that the points of contact are fewer, and consequently the adhesion much less. The ratio of the hollow to the full portions is much greater than in the simply twisted cable; it varies from 0.15 to 0.30 according to the number of wires. Before the cable is manufactured the wires are passed through a bath of inoxidisible composition; then as each layer or crown is added, the cable passes anew through this bath, so that all the layers are covered, and the interior spaces between tangent circumferences are filled with this composition.'
Arnodin and Alberto de Palacio designed and oversaw the construction of the world's first transporter bridge Alberto de Palacio, which they first patented in 1887.
Nine of the eighteen known examples of the transporter bridge may be attributed to Arnodibn, and three of the nine still exist. They use the technology of both suspension bridges and cable-stayed bridges. Arnodin built a great number of second generation suspension bridges at the turn of the 20th century, and he also restored and consolidated a number of old first generation suspension bridges (before 1860): the aprons were reinforced and the old wire cables replaced by spirally-wound double torsion steel wire ropes, often with addition of a cable-stayed bridge (known structural modification under the name of “Système Arnodin”). His structural engineering factory was established in Châteauneuf-sur-Loire. [2]
1906 'Two rigid suspension bridges, involving a novel and important detail of construction, have been recently designed to carry the railway from Villefranche to Bourg-Madame over the river Yet at different sites. The scheme of the structures is the conjoint production of M. Gisclard and his collaborator M. Arnodin, the latter gentleman being an engineer well known for his work in connection with the erection of transporter bridges. .....'[3]
See here for a list of Arnodin's structures and projects, with links to further information.
Photo of Arnodin's Pont du Midi over the Saone at Lyon here.
A French book, published in 2010, provides a superbly-illustrated account of the life and work of Arnodin and his Company. It does not focus on technical aspects.[4]
See Also
Sources of Information
- ↑ [1] 'Paris Universal Exposition, 1889: Civil Engineering, Public Works, and Architecture' by William Watson. Washington, Government Printing Office, 1892, p.751
- ↑ [2] Wikipedia - Ferdinand Arnodin
- ↑ The Engineer 26 Jan 1906, p.98
- ↑ Ingénieurs des ponts. L'histoire de la famille Arnodin - Leinekugel Le Cocq de 1872 à 2002 by Didier Leinekugel Le Cocq. Paris, éditions La Vie du rail, 2010