J. Augustine DeSazilly

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.

[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.