About Chance® Helical Piers

The helical pile or anchor is a deep foundation system used to support or resist loads in tension or compression, whichever is desired. The piles are installed utilizing equipment ranging from large excavators to lightweight handheld equipment.

The initial “screw pile” was developed in England in 1833 and it worked adequately for its limited uses. Little progress was made on the design concept until the 20th century. In the 1950’s, the A.B Chance Company introduced the Power Installed Screw Anchor for resisting tension loads. This anchor consisted of a shaft, a plate and was installed utilizing torque supplied by a motor. As this product was widely accepted, research and development began around utilizing the pier in compression as well as tension. Research found that this was a very acceptable means to resist compression loads and was quickly adopted for many applications.

With the development of higher torque capacities on installation equipment, higher bearing capacities per pier through larger helices, multi helix piers, different shaft sizes, and stronger (larger) shafts, the Chance Helical Pier has been utilized for higher load applications.

Further research was completed on helical piers in compression. Slenderness of the shaft and local buckling was a large concern for engineers in soft upper soils (SPT values 4 or less). The patented Helical Pulldown® Micropile was developed which involves placing a soil displacement plate around the shaft as the pier is installed. This displacement plate creates an open space around the helical pier shaft which is filled with grout. In field testing has shown the Helical Pulldown Micropile can achieve very high capacities as a result of both end bearing capabilities and friction along the grouted shaft.  For more information on the Helical Pulldown Micropile, click here.

How Chance® Helical Piers Work?

Helical piers and anchors are end bearing foundation elements, meaning the load is transferred down the solid square steel shaft into the helical bearing plates and into the load bearing soil.  By applying torque to the shaft, the helices penetrate the soil by minimally displacing the soil on either side of the helices. The friction that is created between the helical plates and the soil during installation requires torque to install it into the soil. The torque that it takes to install the screw anchor is measured and correlates directly back to the capacity of the pier. For more information on the theory of how helical piers work, see Foundation Anchor Design Theory.

Why Use Chance® Helical Piers?

• Making deep foundation products for over 100 years
• ISO 9001 Registered facility utilizing the best quality steel products
• Products are hot dip galvanized
• Technical Support and years of expertise of AB Chance and EBS Engineering and Construction Limited
• Accessibility to limited access sites
• No vibration, spoils or excavation required
• Immediate loading of helical piers and anchors
• Torque to capacity relationship for quality assurance on every pier installed
• Environmentally friendly
• Made from recycled steel (LEED Credits available)

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