Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

89 OF ENGINEERING FOBMULÆ. Stability of Walls, &c. H = Height of the wall. A = Height of centre of pressure from base. = H 4- 3 for still water. B = Breadth of wall against which pressure acts. W = Weight of the wall. y = Distance of outer edge of the wall from the line of centre of gravity of the wall. P — Pressure tending to overturn the wall. m = Moment tending to overturn the wall. — PA = 10’4 1I1> for water* in pounds. M = Moment of stability of wall. = W.y. . If M exceeds m, the wall will be stable pro- vided that the materials on which it is constructed or the foundations on which it rests, are suffi- ciently strong to resist crushing, * H being the height of the surface of the water from the base.