Aggregate Piers (Stone Column) is a ground improvement technology that uses stiff aggregate piers to reinforce or densify soils. They can be utilized in most soil types and design applications. An element is pre-drilled at the aggregate pier location to design depth. The vibrator is lowered down the drill hole and aggregate is added to the hole and densified in lifts for the top feed method. In collapsible soils, the bottom feed method is utilized. Aggregate is added through the bottom feed rock tube and the aggregate is densified in lifts.