Terzaghi's Bearing Capacity - Circular Foundation

More Cases

Terzaghi's Circular Foundation

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 strip foundation, ft or m
  • c' = effective cohesion of soil, lb/ft2 or kN/m2
  • Df = depth of ground foundation measured from ground surface, ft or m
  • Kp = passive pressure coefficient
  • Nc, Nq, Nγ = bearing capacity factors
  • q = effective unit weight of soil (refer modification for a water table), lb/ft3 or kN/m3
  • qu = ultimate bearing capacity, lb/ft2 or kN/m2 (kPa)
  • γ = unit weight of soil, lb/ft3 or kN/m3
  • ϕ' = effective angle of internal friction, degrees