Does Helix Diameter Affect Uplift Resistance in Sandy Soils?

Yes, helix diameter significantly affects uplift resistance capacity. According to the provided technical guide, the dimensions and configuration of the helix plates are critical factors in determining how much upward force a pile can support.

Key ways helix diameter influences performance include:

• Plate Bearing: Uplift resistance is determined by the helix plate bearing and the shear strength of the surrounding soil. Larger-diameter plates or multi-helix configurations are specifically recommended for applications like solar panel foundations to resist high uplift and overturning forces.
• Soil Type Considerations: While larger diameters are often recommended for cohesive soils (clays), granular soils (sands) may require specific helix spacing and sizing to optimize the soil-helix interaction.
• Force Distribution: Using multiple helix plates of increasing diameter on a single shaft allows the system to distribute uplift forces more effectively than a single helix.
• Standard Sizing: Typical helix diameters range from 6 to 12 inches. The selection of the specific diameter should follow established soil-helix interaction tables and be verified using proprietary design software like HeliCAP® to ensure it meets site-specific soil conditions.

• Uplift Resistance Capacity: Essential Guide for Engineers