Stress Distribution and all of its mysteries

I. The Bulb of Pressure Force

I. The Bulb of Pressure Force “what are the stresses at this point?”

(boo-sinn-esk) II. The Boussinesq Equation A. Goal: to determine the vertical and horizontal stresses under a point load in a homogeneous, isotropic medium. Allows us to determine vertical and horizontal stresses at any point in space Examine the transmission and distribution of stresses in large, extensive masses of soil. Culvert?

II. The Boussinesq Equation B. The Equation:

II. The Boussinesq Equation B. The Equation: Where v = Poisson’s Ratio (0.48) Also an equation for σy

6.71

If Poisson’s ratio is ~0.5, equations simplify to: σx = 3Px2z 2π R5 σy = 3Py2z 2π R5

Your turn: Vertical load of 2500 lb/ft2 Determine horizontal (x) and vertical (z) stresses at X= 5, Y= 2, Z = 6