Stress Below a Foundation - Approximate Method

More Cases

60 degree Through Soil Method

Notation and Units

Metric and Imperial Units

The above formulas may be used with both imperial and metric units. As with all calculations care must be taken to keep consistent units throughout with examples of units which should be adopted listed below:


  • B = width of foundation, ft or m
  • L = length of loaded area, ft or m
  • q0 = load per unit area, kip/ft2 or kN/m2
  • z = vertical distance from load to point of interest, ft or m
  • ∆σ = stress increase at point of interest, kip/ft2 or kPa