CHANCE® Helical Pulldown® Micropiles
What is a Micropile?
Micropiles are a type of small-diameter pile, usually between 5-12 inches, used for sites with especially weak surface soil.
Developed in 1997, this patented innovative application of the helical minipile integrates portland cement-based grout to increase the section properties of the shaft. The Helical Pulldown Micropile (HPM) brings the advantages of the pre-engineered helical micropile design to higher load applications, providing compression loads of 20,000 lbs. to 400,000 lbs. per pile. By “pulling down” a special flowable grout as the micropile foundation is screwed into the soil, these helical micropiles create a deep foundation with both a friction-bearing central shaft and end-bearing helical plates in competent substrata.
Benefits of the CHANCE® Helical Pulldown® micropile system include:
- Resistance to buckling in weak surface soils
- Higher load capacity
- Stiffer pile (deflects less at a particular load)
- Additional corrosion protection in aggressive soils
How the Helical Pulldown® Micropile Works:
The Helical Pulldown® Micropile design is a system for constructing a grout column around the shaft of a standard helical minipile system. To begin the process, a helical pile is placed into the soil by applying torque to the shaft. The helical shape of the bearing plates creates a tremendous pulling force that keeps the anchor advancing downward into the soil. After the lead section with the helical plates penetrates the soil, a lead displacement plate and extension are bolted onto the shaft.
Resuming torque on the assembled shaft advances the helical plates and pulls the displacement plate downward, forcing soil outward to create a cylindrical void around the shaft. From a reservoir at the surface, a flowable grout immediately fills this void, surrounding and encapsulating the shaft. Additional extensions and displacement plates are added until the helical bearing plates reach competent load-bearing soil. The Helical Pulldown® Micropile displaced the soil around the shaft, eliminating the need to remove spoils from the site.
Working on a design project using helical piles and anchors? HeliCAP™ is a free civil engineering software platform that helps calculate capacity requirements for CHANCE® helical products. Control for soil parameters, environmental variables, and other essential criteria to select the appropriate pile/anchor size needed for your individual project requirements.
Helical Pulldown® Case Studies:
- Dry Tortugas National Park
- Rumfish Aquarium
- Historic Jefferson High School Restoration
- YMCA of Northwest Florida
Request a Quote
Have questions about any of our foundation CHANCE® Helical Pulldown® Micropile products? Ready to get started on your next project? Looking for expert advice? Request a quote now to speak with our professional team of experts about specifications, pricing, and any additional questions you may have. We’ll get back to you within one business day.