Helical Anchoring Systems

Pulldown Micropiles

A.B. Chance Helical Pull Down Micro Pile is a system for constructing a grout column around the shaft of a standard A.B. Chance Helical Pier foundation system.

The micropile system is installed by screwing a helical pier into the ground by applying torque to the shaft. The helical shape of the bearing plates creates a tremendous pulling force enabling the anchor to dig into to soil. Once the helical has reached its optimal depth, a container filled with grout is placed around the pier. Lead displacement plates and extension plates are placed around the shaft of the pier. As the helical pier advances in the soil, the plates push the soil outward from the pier shaft thus forming an annulus (void) area around the shaft. The grout, as a result of gravity, will flow downward to fill the voids as the pier advances into the soil.

The pulldown micropiles may be used for commercial and industrial construction. Typically, micropiles are specified for new construction applications, building additions, and retrofit applications. The pulldown micropiles provide an end bearing/friction composite pile in which capacities have been tested up to 300 kips. The system transfers load through weak soils to high bearing capacity helical plates. The column sizes range from 4"-10" in diameter.

Advantages of the pulldown micropiles are they may be installed in limited access areas, no excavation or spoils, and are a cost-effective proven process.

Installing Pull-Down Micropiles - Lewis and Clark Boathouse, St Charles, MO: