Paul Séjourné

Paul Séjourné (21 December 1851; Orléans – 19 January 1939; Paris) was a French engineer who specialized in the construction of large bridges from masonry, a domain in which he made some important innovations.

In 1896 he left the civil service and joined the Chemins de fer de Paris à Lyon et à la Méditerranée (PLM) as chief engineer based in Dijon, all the while continuing to lead other important projects such as the Adolphe Bridge in Luxembourg.

Between 1901 and 1922, Séjourné taught the construction of large masonry bridges at the ENPC and published a 6 volume manual Grandes Voûtes ('Great Arches) which brought together all his knowledge on the subject.

[3] Paul Séjourné developed some technical innovations : Design and calculation of Centring : Séjourné demonstrated the value of constructing arches by parallel sections, so that the centering only had to support the weight of the section under construction.

Séjourné showed that the older technique was perfectly viable and could lower the weight and cost of the centering by up to 70%.

While his contemporaries such as Gustav Eiffel resorted systematically to metalwork, Séjourné continued to design and build large span arch bridges in masonry until the end of the 1920s.

The line was never completed and the viaduct is now submerged in the Serre-Ponçon reservoir, but visible when the water level falls.

1912 : Morez viaducts in the Jura on the Andelot-en-Montagne - La Cluse line and the Pont Sidi Rached, Constantine (Algeria).

1908 : Bort-les-Orgues to Neussargues railway line in the Massif Central, 1920 to 1934 : in Morocco, the building of the Casablanca - Oued-Zem lines, at Rabat and Marrakech, and the Fez - Oujda junction completing the "imperial way" between Marrakesh and Tunis.