Geopier GP3® System

The Geopier GP3 System uses replacement Rammed Aggregate Pier® (RAP) elements to reinforce good to poor soils, including soft to stiff clay and silt, loose to dense sand, organic silt and peat and variable, uncontrolled fill. It's the ground improvement method that started a revolution! The unique installation process utilizes pre-augering and vertical impact ramming energy to construct RAP elements, which exhibit unsurpassed strength and stiffness. RAP solutions are designed to provide superior total and differential settlement control and increased bearing support to meet project requirements.


  1. The process first involves drilling a cavity. Drill depths normally range from about 7 to 30 feet, depending on design requirements. Pre-drilling allows you to see the soil between the borings, ensuring that the piers are engineered to reinforce the right soils.    
  2. Layers of aggregate are then introduced into the drilled cavity in thin lifts of one-foot compacted thickness. A patented beveled tamper rams each layer of aggregate using vertical impact ramming energy, resulting in superior strength and stiffness. The tamper densifies aggregate vertically and forces aggregate laterally into cavity sidewalls. This results in excellent coupling with surrounding soils and reliable settlement control.
  3. Following installation, RAP elements reinforce slopes and embankments, support shallow foundations, floor slabs and tank pads. The footing stresses are attracted to the stiff RAPs, resulting in engineered settlement control.

Construction Advantages

  • Better quality control through visual inspection of drill spoils and modulus tests with telltales
  • Environmentally safe and sustainable offering LEED® point enhancement
  • Clean and rapid installation process
  • Accelerated schedules
  • Versatile system allows for use in a wider range of structures
  • Reliable and cost effective

Design/Performance Advantages

  • Stronger and stiffer elements
  • Excellent settlement control
  • Superior support capacity
  • Increased bearing pressure up to 10,000 psf
  • Designed for structural support of buildings
  • Often results in 20% to 50% savings
  • Engineered to meet specific soil conditions and loads
  • Wind and seismic uplift resistance
  • More than two decades of proven foundation support

Geopier GP3 support (you can see the aggregate piers) for Mayo Clinic, Northfield, MN


  • Foundations
  • Floor Slabs
  • Biofuel Facilities
  • Industrial Tanks
  • Wind Turbines
  • Transportation
  • MSE Walls
  • Embankments
  • Railroad
  • Liquefaction/Seismic Uplift and Lateral Load Resistance
  • Slope Stabilization