J. Augustine DeSazilly

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J. Augustine DeSazilly (fl. mid-19th century) was a French engineer.

In the early 1850s, DeSazilly published a paper postulating the "profile of equal resistance," a major theoretical advance in the technology of masonry gravity dams, based on the hydrostatic force exerted by a given height of water in relation to the weight of masonry used in the dam's construction (estimated at 150 pounds per cubic foot). DeSazilly considered two extreme conditions, a filled reservoir and an empty reservoir, and created a model for equalizing stresses on the masonry across every horizontal cross section. He developed a vertical cross section in which the stresses at the upstream face of a masonry gravity dam with the reservoir empty are equal to those at the downstream face with the reservoir filled. His hypothesis provided a means of calculating the minimum amount of material that could be used while assuring stability. Although he himself never carried out the construction of a dam on this "profile of equal resistance," it was used in 1858 to build the Furens Dam across the Loire River.[1]

DeSazilly also developed a process of surface drainage for building on a slope,[2] and contributed to the building of railways,[3] roads, and bridges.[4]


  1. ^ Donald C. Jackson, Building the Ultimate Dam: John S. Eastwood and the Control of Water in the West (University of Oklahome Press, 2005), pp. 22–23 online.
  2. ^ Charles Couche, Permanent Way Rolling Stock and Technical Working of Railways (London, 1877, translation of French edition) vol. 1, p. 471 online.
  3. ^ Annales des ponts et chaussées (Paris, 1852), pp. 93–93 online; Annales des mines 5 (1854), pp. 411–412 online; Auguste Perdonnet, Traité élémentaire des chemins de fer (Paris, 1865),vol. 1, p. 458 online.
  4. ^ French Ministry of Agriculture, Commerce, and Public Works, Notices sur les modèles, cartes et dessins relatifs aux travaux publics (Paris, 1867), p. 27 online; Annales des ponts et chaussées 13 (1887), p. 675 online.

External links[edit]

  • A diagram of DeSazilly's "profile of equal resistance" may be viewed in The History of Large Federal Dams: Planning, Design, and Construction (Government Printing Office, 2005), p. 52 online.