François Coignet

François Coignet (10 February 1814 – 30 October 1888) was a French industrialist and a pioneer in the development of reinforced concrete as the first person to use iron-reinforced concrete to construct buildings.Day, p. 284

Biography

Coignet, along with his brothers Louis (b. 1819) and Stephane (b. 1820), took over the family business, a chemical plant in Lyon, in 1846. In 1847, he built some concrete houses using poured cement that was not reinforced with iron.

In 1850, Coignet married Clarisse Gauthier (1823-1918) and a year later, he settled in Saint-Denis, a commune near Paris, where in 1852 he opened a second plant and obtained a patent for cement clinker. Coignet then built a cement factory at Saint-Denis using exposed lime walls and followed the pisé de terre system, a rammed-earth method of construction. This was the first time he worked with this method in concrete. Later, he took out a patent in England entitled "''Emploi de Béton''", which gave details of his construction techniques.

Coignet started experimenting with iron-reinforced concrete in 1852 and was the first builder to use it as a building material. He decided, as a publicity stunt and to promote his cement business, to build a house made of ''béton armé'', a type of reinforced concrete. In 1853, he built the world's first iron-reinforced concrete structure, a four-story house at 72 rue Charles Michels in St. Denis. The house was designed by local architect Theodore Lachez.Collins, p. 28

File:72 rue Charles-Michels drawing 1855.jpg, alt= 1855 architectural drawing, 1855 architectural drawing
File:Masion Coignet 1.jpg, alt= Masion Coignet facing east and north, Facing east and north
File:Maison François Coignet 2.jpg, alt= Masion Coignet facing south and east, Facing south and east
File:Saint-Denis - Maison François Coignet -1.JPG, alt=72 rue Charles-Michels in 2010, 72 rue Charles-Michels in 2010

In 1855, a committee of fourteen architects led by Henri Labrouste inspected the house. In Labrouste’s report, he said all of the work for the house was done entirely of cement and artificial stone. It also showed Coignet used different materials of little value and mixed them with lime and water to make decorative moldings and cornice that crowned the building. The railing was also a molded concrete mass. In March of that year, he had taken out a patent entitled ''Béton Économique'' that showed how inexpensive aggregates could be used in concrete. He then built several more concrete houses that were still standing in 2021.

This report showed Coignet made a concrete mixture of wood ash and slag with lime and then used this mixture in the rammed earth method of construction. The report said the committee had doubts about the soundness of Coignet's techniques and that they could be dangerous. As of 2021, the house has been abandoned for many years and squatters have periodically taken over the property. While it has deteriorated, the house is classed as a world patrimony and has been classified as a historical monument since 1998.

Coignet had an exhibit at the 1855 Paris Exposition to show his technique of reinforced concrete. At the exhibit, he forecast the technique would replace stone as a means of construction. In 1856, he patented a technique of reinforced concrete using iron '' tirants''. In 1861 he published his techniques.

Coignet is the inventor of molded concrete, which is known as ''Béton Coignet''. He had much success building with this technique. He became a renowned building contractor and showed his many designs, including the molded concrete church of Le Vésinet near Paris, which, with its spire, is the first modern monumental concrete building.

Construction projects

One of Coignet's largest projects was the of the '' Aqueduct de la Vanne'' (Paris metropolitan water supply) with over of arches of over -high spans. He built the aqueduct between 1867 and 1874. Coignet also helped construct the lighthouse at Port Said, Egypt, the high retaining walls of the Passy Cemetery and Trocadéro Cemetery in Paris.Concrete and constructional engineering, p. 159
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Gallery

File:Egypt-IMG 0960.jpg, alt=Lighthouse of Port Said in Egypt, Lighthouse of Port Said
Port Said, Egypt
File:Cimetiere de Passy walls.jpg, alt= Passy Cemeter walls in Paris, Passy Cemetery walls
Paris, France
File:Trocadero and cemetery.jpg, alt=Trocadéro and cemetery in Paris, Trocadéro and cemetery
Paris, France
File:Saint Jean de Luz 002.jpg, alt=Far view of sea wall at Saint-Jean-de-Luz, France, Far view of sea wall at
Saint-Jean-de-Luz, France
File:Sea wall at Saint Jean de Luz.jpg, alt=Close-up of sea wall at Saint-Jean-de-Luz, France, Close-up of sea wall at
Saint-Jean-de-Luz, France

See also

* Edmond Coignet
* Reinforced concrete
* New York and Long Island Coignet Stone Company Building

Notes

References

* Collins, Peter et al., ''Concrete: the vision of a new architecture'', McGill-Queen's Press - MQUP, 2004,
* Day, Lance, ''Biographical Dictionary of the History of Technology'', Routledge, 2003,
* Encyclopædia Britannica, 1993, ''The New Encyclopædia Britannica: micropaedia: ready reference'', Edition: 15, illustrated,
* Sutherland, R. J. M. et al., ''Historic Concrete: Background to Appraisal'', Thomas Telford, 2001,

{{DEFAULTSORT:Coignet, Francois
1814 births
1888 deaths
Concrete pioneers
Engineers from Lyon
French civil engineers
Structural engineers