Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

91 OF ENGINEERING FORMULÆ. INEQUALITY OF PRESSURE ON FOUNDATIONS DUB TO LATERAL FORCE. M = Moment of lateral force about axis of foundation. p = Pressure per unit of surface from fixed load. P — Greatest pressure per unit of surface from fixed load and lateral force together. y — Distance from axis to edge of foundation, I — Moment of inertia of plane of founda- tion about axis. M V P =/> + -/ FOBM OF PIER' TO SUSTAIN EQUAL PRESSURE PER UNIT OF SURFACE AT EVERY HORIZONTAL SEC- TION. H = Height of a column of the material of which the pier is built, corresponding to the given pressure. a — Area of top section of pier. A = Area of horizontal section at depth h. h = Depth measured from the top. r = The number whose hyperbolic log. = — • A -; a x rh, or, in other words, A = a N, where N = that number whose common log. • 43429h is equal to---• The contents of the pier = H (A — a).