Geogrid pullout capacity calculator.
Pullout resistance F = 2 × Lₑ × Cᵢ × σᵥ × tan φ', per BS 8006 and FHWA-NHI-10-024. Factor 2 accounts for top and bottom surfaces of the geogrid sheet engaging with soil. Calculator returns pullout capacity per metre width and a factor of safety against design tension. Use to verify each reinforcement layer in an MSE wall or RSS design.
Interaction coefficient by geogrid-soil pair.
| Geogrid type | Fill type | Typical Cᵢ |
|---|---|---|
| StrataGrid uniaxial PET (PVC coated) | Well-graded crushed aggregate | 0.85-0.95 |
| StrataGrid uniaxial PET | Granular sand-gravel mix | 0.75-0.85 |
| StrataGrid uniaxial PET | Silty sand (Malaysian residual soil) | 0.65-0.80 |
| StrataGrid biaxial PP (SGB) | Crushed aggregate base | 0.80-0.90 |
| StrataGrid biaxial PP | Granular sand | 0.65-0.80 |
| Generic woven PET | Granular fill | 0.50-0.70 |
For project-specific Cᵢ, request the STRATA datasheet pullout test result against your fill grading; we hold these for Malaysian fills under the distributor appointment.
Top layers vs bottom.
In MSE walls, pullout usually governs design at the top reinforcement layers because σᵥ is small there (low embedment depth), while design tension T may still be substantial because of surcharge. At the bottom layers, σᵥ is high and pullout is rarely critical; rupture governs there instead. Always verify pullout at every layer, not just the bottom. Use the table below as a starting point:
| Layer position | Likely governing mode |
|---|---|
| Top 1-3 layers | Pullout (low σᵥ) |
| Middle layers | Mixed pullout / rupture |
| Bottom 2-3 layers | Rupture (high T, high σᵥ) |
Other tools.
Need pullout test data for a specific fill?
WhatsApp the gradation curve; we'll send the matched STRATA datasheet.