Size helical ground screws for solar PV foundations using torque-to-capacity correlation factor.
Input Parameters
Results
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Ultimate Capacity
lbs
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Allowable Compression
lbs
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Allowable Uplift
lbs
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Capacity Status
Note: Helical ground screws (piles) are installed by torque. The Kt factor depends on soil type and helix configuration. Verify Kt with field load testing.
Reference
Qu = Kt × T (ICC-ES AC358)
Kt = torque correlation factor (7-14 ft⁻¹)
Allowable Compression = Qu / SF
Allowable Uplift = Qu × 0.75 / SF
Typical SF = 2.0 for ASD design