Bearing Capacity Calculator
Calculate a simplified gross ultimate pressure and arithmetic qult/FS comparison for a strip footing.
A QUICK WALKTHROUGH
How to use this tool
- Enter soil strength, unit weight, footing width, embedment depth and factor of safety.
- The model derives the declared simplified strip-footing factors from your friction angle and reports gross ultimate pressure and the arithmetic division by your factor of safety. Keep all lengths and pressures in consistent units.
- Calculate
Model and limits
Terzaghi general-shear strip-footing form: qult = cNc + γDfNq + 0.5γBNγ. Declared model factors, with φ in radians: Nq = exp((1.5π − φ)tanφ)/(1 − sinφ); Nc = (Nq − 1)/tanφ, using its continuous limit 1 + 1.5π at φ = 0. Nγ ≈ 1.5(Nq − 1)tanφ is an approximation, with Nγ = 0 at φ = 0. These are the declared educational coefficients, not strict classical tabulated values. Assumes homogeneous soil, a rigid continuous strip footing, vertical centered loading, general shear and no groundwater correction, inclination, eccentricity, layering, settlement or code-specific resistance factors. The reported qult/FS is only an arithmetic comparison; it is not a design value or recommendation.
Source
The gross ultimate equation follows the Terzaghi-style general-shear strip-footing form. The precise factor equations and Nγ approximation used here are declared above; no classical table agreement is claimed. This educational simplification must not be used to size or approve a foundation.
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GOOD TO KNOW
Common questions
Is this a foundation design?
No. It is a limited educational calculation and omits site investigation, settlement, groundwater, load combinations, local codes and professional review.