Geotechnical Engineering
Bearing Capacity Calculator
Screen shallow foundation bearing capacity using a Terzaghi-style calculation.
Parameter sketch
Shallow footing bearing model
Labels update with the current input values so the formula symbols stay tied to the geometry.
Result
Allowable bearing pressure: 4000.33 psf or kPa in consistent input units
Nc
30.14
Nq
18.4
N gamma
22.4
Ultimate bearing capacity
12001
Allowable bearing capacity
4000.33
Step-by-step calculation
- Compute surcharge at footing base: gamma x Df = 120 x 3 = 360.
- Bearing factors for phi = 30 deg: Nc=30.14, Nq=18.4, Ngamma=22.4.
- Cohesion term = 0; surcharge term = 6624.4; width term = 5376.6.
- Ultimate capacity = 12001; allowable = 12001 / 3 = 4000.33.
What this means
This is a preliminary Terzaghi-style estimate. Settlement, groundwater, load inclination, and local code checks may govern design.
Formula Used
qu = cNcsc + gamma Df Nq + 0.5 gamma B Ngamma sgamma
Step-by-Step Example
For c=0, gamma=120 pcf, B=4 ft, Df=3 ft, phi=30 deg, FS=3, allowable pressure is about 2,992 psf.
Engineering Notes
Check units, assumptions, boundary conditions, groundwater, drainage, and whether the simplified method is appropriate before using a result in any project decision.
FAQ
Does the calculator include settlement?
No. Bearing and settlement are separate checks; settlement often controls.
Can I use metric units?
Yes, if all stress and length inputs are internally consistent.