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SPT & Bearing Capacity
Correct field SPT N to N60 and (N1)60 and get the allowable bearing pressure for a footing (Meyerhof, 25 mm settlement) in kN/m² and ton/ft².
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About this test
Enter the SPT blow count, depth and hammer details to get corrected N values, sand density and the allowable bearing pressure for your footing width.
How it's calculated
- N60 = N × (Er/60) × Cb × Cs × Cr
- (N1)60 = N60 × √(100/σ′v) ≤ 1.7 N60
- qa = N60/0.05·Kd (B ≤ 1.2 m) or N60/0.08·((B+0.3)/B)²·Kd
Results are calculated from the values you enter using standard formulas. Download the PDF to keep a record. For certified testing, design or construction, talk to our engineers.
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