Pile bearing capacity from SPT data

What the tool calculates

• Comparison of Aoki-Velloso, Décourt-Quaresma, Teixeira and other semi-empirical methods
• Manually entered or imported SPT profiles, with N-values capped at the refusal threshold
• Global factor of safety from NBR 6122:2019: 2.0 for semi-empirical methods; 1.6 with load testing at the design stage
• Caution for lateritic soils, where conventional methods may underestimate the capacity of continuous flight auger piles

What you enter

• Borehole profile with SPT N-values by depth and the recorded groundwater level
• Pile type and geometry (diameter and length)
• Methods to compare

What you receive

• Allowable load calculated by each selected method
• Separate base and shaft resistance components
• Calculation report identifying the source of each correlation

References and limits of applicability

• ABNT NBR 6122:2019 + Emenda 1:2022 — Foundation design and construction (global factor of safety, Table 1)

Checks and considerations

• Continuous flight auger pile capacity may be underestimated in lateritic soil; assess whether load testing is needed
• SPT N-values above the refusal threshold are capped in the calculation

How it works

Semi-empirical methods estimate base resistance and resistance along the shaft separately, using the borehole data and pile type. The allowable load takes the applicable safety criteria into account. Selecting a method requires an assessment of the soil, construction conditions and limitations stated in the report.

Example of use

To compare foundation options for a building, load the SPT profile and enter a pile configuration. Select the available methods and examine how base and shaft resistance vary before agreeing on a solution with the engineer responsible for the design.

Frequently asked questions

Does the tool replace an engineer's design?

No. The tool supports preliminary design and calculation review. Method selection, data validation, design and the Brazilian registration of technical responsibility (ART) remain the responsibility of the engineer in charge.

Where do the soil parameters come from?

The parameters are derived from the borehole data entered and the correlations used by the selected method. Review their sources, assumptions and limits of applicability in the calculation report.

Generated documents

These documents are assembled within your project using data from the corresponding tools.

• Foundation calculation report — Combine the project's SPT logs, bearing capacity calculations and structural designs for piles, pile caps, footings and belled caissons in one PDF. The document consolidates selected items; technical checks remain within each tool.