Limitations of Square Shaft Helical Piles

Friday, July 22nd, 2016 By Jaimie Hooker

Solid Square shaft helical piles have been used successfully for decades in tension applications. Helical tieback and soil nail applications further proved the product’s effectiveness to resist even moderate to high tension loads, while being installed efficiently with socket-like drive tools and smaller equipment. Unfortunately, about 30 to 40 years ago, a select few contractors and manufacturers began promoting the use of square bar products for vertical applications where they are not well suited; i.e., to resist compression loads on new construction and retrofit piering projects. With just a little understanding of these products and coupling details, most design professionals can quickly identify the inherent strengths and weaknesses of the square bar system, and then make the correct choice between solid square and hollow round shaft.

As the picture shows the forged and upset square bar couplers, although relatively economical to create, have large gaps, creating a “hinging” about the coupling bolts. Upsetting is also not a well-controlled manufacturing process to guarantee direct bearing between pile sections. In short, solid square shaft helical piers are best suited for tension applications while a hollow round shaft helical should be used to resist compression loads.

Tar Heel Basement Systems recommends using the round shaft helical piles to better suit compression applications. The round helical piers are mechanically screwed into the soil to the appropriate depths and capacities preventing further settlement.

The round Helical Pier System from is able to permanently stabilize your home’s foundation and provide an opportunity to lift your home back to level without the expense and disruption of a full foundation replacement.

About the author
Jaimie Hooker is the Assistant Marketing Director at Tar Heel Basement Systems; authoring case studies, technical papers, creating and captioning photo albums and managing website content. She also oversees the organization of video testimonials, shows and events, Jaimie lives in the small town of Madison, NC with her husband, Paul, and 3 year old son, Franklin.