Foundations · Pile capacity

Helical (screw) pile capacity calculator

Compression capacity as the sum of helix bearing (c Nc + q′ Nq) plus torque-correlated capacity for comparison.

Standard: Individual plate bearing method · torque correlation (Perko)

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Diagram for the worked example

Helix area = PI()*(450/1000)^2/4 = 0.15904 m²
Nq = EXP(PI()*TAN(RADIANS(32)))*TAN(RADIANS(45+32/2))^2 = 23.177
Mean helix depth = 6-(2-1)*1.35/2 = 5.325 m
Σ Ah (9c + γ z Nq) = 2*0.15904*(9*0+10*5.325*23.177) = 392.57 kN
Torque capacity Kt T = 23*15 = 345 kN
Allowable min(Qh, Qt)/FS = MIN(392.57,345)/2 = 172.5 kN

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For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.