Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

116 Molesworth’s pocket-book Pile Driving. D = Set of pile by the last blow in inches. H = Height the ram has fallen in inches. L = Safe load for the pile in cwts. L = WH J 8 D approximately. (Sanders.) W = Weight of ram in cwts. W - 10 to 14 cwt. in ordinary pile engines. Rankine s rule for Lis 1000 lbs. per square inch of section when the pile is driven home to firm ground, and 200 when it is not another rule. (Rankine.) W = Weight of ram. A = Height of fall. d = Depth driven by last blow. s = Sectional area of pile. I = Length of pile. E = Modulus of elasticity. L = Greatest dead load the pile will bear without sinking lower. I _ //4EsWÄ 4E3s^2\ 2EsJ L-v (—<—+—--------------------- DUTCH RULE. . L = Load the pile is to bear. W = Weight of ram; h = fall of ditto. M = Weight of pile; k = coefficient of safety. k = 10 for ordinary = 6 for steam pile drivers. e = Average penetration of the last blows. r - W~A k e(W + M) Limit of driving in sand = 15 feet.