Perronet, Jean

▪ French engineer

born Oct. 8, 1708, Suresnes, Fr.

died Feb. 27, 1794, Paris

      French civil engineer renowned for his stone- arch bridges, especially the Pont de la Concorde (Concorde, Pont de la), Paris.

      The son of an army officer, Perronet entered the newly formed Corps des Ponts et Chaussées (Bridges and Highways Corps) and so distinguished himself that on the founding, in 1747, of the École des Ponts et Chaussées, the world's first engineering school, he was appointed director.

      During construction of a bridge at Mantes in 1763, Perronet made the discovery that the horizontal thrust of a series of elliptical arches was passed along to the abutments at the ends of the bridge. Armed with this knowledge, he carried the stone-arch bridge to its ultimate design form with extremely flat arches that were supported during construction by timbering (falsework) and mounted on very slender piers, which widened the waterway for navigation and reduced scour from the current.

      The result was also aesthetically pleasing; Perronet's Pont de Neuilly has been called the most graceful stone bridge ever built. He was 80 years old when he began the Pont de la Concorde, originally called the Pont Louis XV, in 1787. Despite the outbreak of the French Revolution, he kept the work going, completing it in 1791. His memoirs, published in 1782, give a complete account of his career to that date.

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