Pile Capacity Input Form
The page stays in a single content column, while the calculator fields shift to 3 columns on large screens, 2 on medium screens, and 1 on mobile.
Example Data Table
This sample matches the default values loaded in the form.
| Parameter | Sample Value | Unit |
|---|---|---|
| Pile Shape | Circular | - |
| Pile Diameter | 0.45 | m |
| Pile Length | 12.00 | m |
| End Bearing Stress | 1800.00 | kPa |
| Layer 1 Length / Skin Friction | 3.00 / 40.00 | m / kPa |
| Layer 2 Length / Skin Friction | 5.00 / 55.00 | m / kPa |
| Layer 3 Length / Skin Friction | 4.00 / 70.00 | m / kPa |
| Layer 4 Length / Skin Friction | 0.00 / 0.00 | m / kPa |
| Negative Skin Friction | 40.00 | kN |
| Pile Self Weight | 15.00 | kN |
| Safety Factor | 2.50 | - |
| Pile Count / Group Efficiency | 4 / 0.85 | - |
| Approx. Allowable Single Load | 474.22 | kN |
| Approx. Allowable Group Load | 1612.34 | kN |
Formula Used
Shaft resistance equals the sum of layer skin friction multiplied by pile perimeter and embedded layer length.
Toe resistance equals unit end bearing stress multiplied by toe area.
Gross ultimate capacity combines shaft and toe contributions.
Net ultimate capacity deducts adverse drag load and self weight.
Allowable load is net ultimate capacity divided by the chosen safety factor.
Group allowable load equals single pile allowable load times pile count and group efficiency.
How to Use This Calculator
- Select the unit system and pile shape.
- Enter pile length and pile diameter or width.
- Provide toe bearing stress from your soil report.
- Add a safety factor suitable for your project criteria.
- Enter negative skin friction and pile self weight when applicable.
- Fill in each soil layer length and unit skin friction.
- Enter pile count and group efficiency for group analysis.
- Press the calculate button to show the result above the form.
- Review the summary table, soil layer breakdown, and Plotly chart.
- Use the CSV or PDF buttons to export the output.
8 FAQs
1. What does this calculator estimate?
It estimates pile shaft resistance, toe resistance, gross ultimate capacity, net ultimate capacity, allowable single pile load, and allowable group load from simplified static inputs.
2. Is this suitable for lateral or uplift design?
No. This page is aimed at axial compression capacity checks. Lateral response, uplift, settlement, buckling, and structural reinforcement design need separate analysis.
3. What if my layer lengths do not match pile length?
The calculator still runs, but it shows a warning. For a consistent check, the sum of embedded layer lengths should generally match the embedded pile length.
4. Should I enter characteristic or reduced soil values?
Enter values consistent with your design method. Many engineers use representative geotechnical parameters first, then apply the project safety format separately.
5. What does group efficiency mean?
Group efficiency adjusts total group capacity for pile interaction effects. Closely spaced piles can reduce total group performance, so the factor is often below 1.0.
6. Can I use this for square and circular piles?
Yes. The calculator automatically changes the perimeter and toe area equations based on the selected pile shape.
7. How should I choose the safety factor?
Use the factor required by your code, geotechnical report, owner specification, or internal design standard. Typical values vary by method, reliability, and testing support.
8. Can I treat these results as final design values?
Use them for preliminary and checking purposes only. Final pile design should be reviewed against geotechnical recommendations, settlement limits, load combinations, and local code rules.