Paul Séjourné facts for kids
Paul Séjourné (born December 21, 1851, in Orléans; died January 19, 1939, in Paris) was a French engineer. He was very skilled at building large bridges made of masonry (which means using stone or brick). He came up with many new and important ideas for these types of bridges.
Contents
About Paul Séjourné
Paul Séjourné finished his studies at a top engineering school called École polytechnique in 1873. He then went to another famous school, École nationale des Ponts et Chaussées, in 1876. After that, he became an engineer for bridges and roads in Mende in 1877, and later in Toulouse in 1890.
In these jobs, Séjourné was in charge of planning and building many railway lines. He became well-known for his clever and new ways of building. In 1886, he received a very important French award called the Légion d'honneur. This award recognized his designs for long-span bridges on railway lines.
From 1890 to 1893, Séjourné took a break from government work to join a company called Fives-Lille in Spain. In 1896, he left government service for good. He joined the Chemins de fer de Paris à Lyon et à la Méditerranée (PLM) railway company as a chief engineer in Dijon. Even then, he kept working on other big projects, like the Adolphe Bridge in Luxembourg.
In 1909, he became the head of the construction department at PLM. Later, in 1916, a famous general named Marshal Lyautey asked him to be the director of Moroccan railways. Séjourné returned to PLM in 1919 as a vice-director. He retired at 76 years old, with the special title of honorary director.
Between 1901 and 1922, Séjourné also taught about building large masonry bridges at his old school, ENPC. He wrote a six-book series called Grandes Voûtes (which means 'Great Arches'). These books shared all his knowledge about bridge building. He won the Caméré prize in 1918 and was chosen to join the French Academy of Sciences in 1924. In 1926, he received an even higher rank in the Légion d'honneur.
Today, a street in Paris is named after Paul Séjourné, where he once lived.
Paul Séjourné's Smart Ideas
Paul Séjourné came up with several clever new ideas for building bridges:
Building Arches with Less Support
Séjourné found a better way to build the arches of bridges. He showed that you could build them in smaller, parallel sections. This meant that the temporary wooden support structure, called "centering," only had to hold up one small section at a time. Once a section was finished, it could support its own weight. Then, the centering could be moved to support the next section.
The ancient Romans used a similar method to save money. But for a long time, engineers had been building centering strong enough to hold the entire arch at once. Séjourné proved that the older method was still very good. It could make the centering much lighter and cheaper, saving up to 70% on costs!
Using Twin Arches for Bridges
He also introduced the idea of using "twin arches" to support a single bridge deck. He first used this on the Adolphe Bridge. By using two thinner arches instead of one thick one, the total weight of the arches was much less. This also reduced the pressure on the bridge's supports. He used this method again on the Pont des Amidonniers in Toulouse. This "Séjourné design" became very popular and was used in many places outside France.
While other engineers of his time, like Gustav Eiffel (who built the Eiffel Tower), started using metal for their big projects, Séjourné kept designing and building large arch bridges out of masonry. He did this until the late 1920s. After that, it became cheaper to build with concrete.
Bridges and Projects by Paul Séjourné
Paul Séjourné worked on many important projects:
As a Designer
- 1884: Pont Antoinette (also called pont de l’Aiguillou) in Sémalens, the Lavaur railway bridge, and pont de Saint-Waast at Couffouleux. These were all on the Montauban-Ville-Bourbon to La Crémade railway line.
- 1884: Pont de Castelet in Ariège, on the Portet-Saint-Simon to Puigcerda line.
- 1904: Pont Adolphe in Luxembourg. This was a road bridge over the Pétrusse river, with a very long main arch of 84 meters.
- 1907: Pont Séjourné carrying the Avenue Séjourné over the canal de Brienne in Toulouse.
- 1908: Pont de Fontpédrouse (also known as the pont Séjourné) and viaduc de la Cabanasse (1910) on the Cerdagne railway line.
- 1909: Viaduc de Chanteloube on the Ubaye line. This railway line was never finished. The viaduct is now underwater in the Serre-Ponçon reservoir, but you can see it when the water level is low.
- 1911: Pont des Amidonniers, also called pont des Catalans, a road bridge over the Garonne river in Toulouse.
- 1912: Morez viaducts in the Jura mountains on the Andelot-en-Montagne - La Cluse line. Also, the Pont Sidi Rached in Constantine, Algeria.
- 1914: Viaduc de la calanque des Eaux salées, viaduc de Corbière, and viaduc de la calanque de la Vesse. These were all on the Côte Bleue railway line.
- 1915: Mont-d'Or tunnel between Frasne and Vallorbe, on the railway line from Lausanne to Paris.
- 1922: Viaduc de Saorge (Alpes-Maritimes), on the Tenda line from Nice to Cunéo. This viaduct was destroyed by the French army in 1940.
- 1925: Viaduc de Laussonne and Viaduc de la Recoumène, on the le Puy - Aubenas line, which was never opened.
- 1926: Viaduc d’Erbosseria in Peille, Viaduc de L'Escarène, Viaduc du Caï (over the Bévéra river), Viaduc du Scarassouï over the Roya river (destroyed by the German army in 1944), and Viaduc de de Saint-Dalmas-de-Tende. These were all on the Tenda railway line. He also designed a road bridge in Compiègne over the Oise river (destroyed by the French army in June 1940).
- 1928: Viaduc de la Roizonne and Viaduc de la Bonne, on the la Mure - Corps railway line. Today, these are used as road bridges.
As an Engineer
- 1888: Worked on the Trans-Caspian railway project in Samarkand, Uzbekistan.
- 1912: Worked on the Andelot-en-Montagne - La Cluse railway line in Jura.
As a Chief Engineer
- 1908: Oversaw the Bort-les-Orgues to Neussargues railway line in the Massif Central mountains.
- 1920 to 1934: In Morocco, he managed the building of the Casablanca - Oued-Zem lines, lines at Rabat and Marrakech, and the Fez - Oujda connection. This completed the "imperial way" between Marrakesh and Tunis.
- 1926: Oversaw the Tenda line (Nice - Cuneo).
Gallery
See also
In Spanish: Paul Séjourné para niños