Soil Bearing Capacity Calculator
Calculate the bearing capacity of soil using Terzaghi’s theory with transparent inputs for foundation width, depth, soil unit weight, cohesion, and friction angle.
Inputs & Soil Parameters
All inputs must be positive. Defaults illustrate a typical small foundation.
Actions
Reset returns to the example values. Calculations use Terzaghi’s classical factors.
How to Use This Calculator
Enter the foundation width, depth, soil unit weight, cohesion, and friction angle to mirror your project conditions. Click Calculate to see the ultimate bearing capacity and the contribution from each Terzaghi term. The reset button restores the example values.
Methodology
This tool relies on Terzaghi’s bearing capacity formula with fixed bearing capacity factors. Each component (cohesion, depth, width) is calculated before summing them to arrive at the theoretical ultimate capacity. The friction angle appears in the interface for transparency, even though the factor estimates remain constant for compatibility with legacy outputs.
- Required inputs: foundation width, depth, soil unit weight, cohesion, and friction angle.
- The calculator multiplies each input by Terzaghi’s factors (Nc=5.14, Nq=1, Nγ=0.5) before adding them.
- Results are displayed in kilonewtons per square meter and rounded to two decimal places.
Glossary
- B: Width of the foundation (m)
- Df: Depth of the foundation (m)
- γ: Unit weight of soil (kN/m³)
- c: Cohesion (kPa)
- φ: Angle of internal friction (°)
- Nc, Nq, Nγ: Terzaghi bearing capacity factors
Example
For a 2 m wide foundation at 1 m depth with γ=18 kN/m³, cohesion=25 kPa, and φ=30°, the calculator reflects the Stephanic values and returns the ultimate bearing capacity found by summing the three components.
Frequently Asked Questions (FAQ)
What is bearing capacity?
It is the capacity of soil to support the loads applied to the ground.
How is bearing capacity calculated?
The calculation uses geotechnical principles considering soil properties, foundation geometry, and depth.
Why is soil bearing capacity important in construction?
Understanding it ensures safety and stability of buildings and foundations.
What factors affect bearing capacity?
Soil type, moisture content, density, foundation depth, and width are key factors.
How can I improve soil bearing capacity?
Techniques include compaction, improving drainage, and soil stabilization.