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:

Notation

• B = diameter of loaded area, ft or m
• I_C = Boussinesq stress co-efficient
• q = load per unit area, kip/ft² or kN/m²
• r = horizontal distance to point of interest, ft or m
• z = vertical distance from load to point of interest, ft or m
• α & β = angle of interest, degrees
• v = Poisson’s ratio
• ∆σ = stress increase at point of interest, kip/ft² or kPa