The Stresses in Masonry Dams

Abstract

IF Prof. E. Brown will refer again to my letter published in NATURE of January 2, he will see that I specifically stated that I did not question that in so far as the dam acted as a horizontal beam, the stresses and will be different in an actual dam and a slab dam. The real point is that Prof. Karl Pearson has said that, apart from any action of this kind, the stresses and in a slab dam and in an actual dam are widely different. Thus, on p. 11 of Pearson and Pollard's paper, he says Messrs. Wilson and Gore put the stress zero, and “hence the vertical and horizontal pressures they calculated have no direct application to real dams.” He has since explained in Engineering, September 20, 1907, that he did not here refer to any action of the kind mentioned by Prof. Brown and by myself in my original letter to you, but that, apart from any action of this kind, the stresses and are entirely different in a slab dam and a long dam. Messrs. Wilson and Gore deduced the stresses for their slab by the equations where E is Young's modulus, e₁ and e₂ the measured strains, and m Poisson's ratio. So far as I can see, these equations give correctly the stresses and for the slab, and if my reasoning in my previous letter to you is correct, these stresses will be unaltered when the slab forms part of a complete dam and is then exposed to stresses at right angles to the plane of the other two.