How It Works

A helical pier is a deep foundation. Its purpose is to transfer a structural load to deeper, stronger, and less compressible materials bypassing any weaker and more compressible materials that would be unsuitable for the support of a conventional shallow foundation. As a deep foundation, a helical pier should be considered for most applications that would call for a driven pile, drilled pier, or mini pile.

The unit is called a helical pier if it resists compressive loads, which are usually downward. It is called a helical anchor if it resists tensile loads, which are usually upward or inclined. Many helical units function as both piers and anchors.

A helical unit is installed by simply screwing it into the ground. The central shaft may be round or square and it may be hollow or solid. Hollow (pipe shafts) are often preferred, because they provide a greater section modulus for the same cross-sectional area of steel. Pipe shafts, as compared to solid shafts, generally provide greater resistance to installation torques and buckling under compressive loads.

Simply put, the helical unit transfers tension or compression load to competent soil strata below incompetent soils.

Tension Load	Compression Load