A drill rig, backhoe, and excavator all work at the same spot on a foundation

Warehouse/Distribution Center Ground Improvement

Michels Construction, Inc. built 6,000 vibrated aggregate piers to construct a shallow foundation system supporting an 850,000-square-foot warehouse and distribution center. The aggregate piers were 30 inches in diameter and installed underneath column spread footings and exterior wall footings on a 121-acre site.

First, Michels Construction pre-drilled the entire depth of columns using an auger drill rig. Then a vibrating probe was inserted in each pier as stone was poured into the pier. The probe imparts vibratory energy to the stone backfill and locks it into place into its tightest configuration, creating a column of highly compacted aggregate that acts as a very stiff spring.

The aggregate piers were designed to increase the soil’s load-bearing capacity and reduce the settlement to an inch or less. The soil conditions onsite ranged from stiff to very stiff lean clay over limestone bedrock, which we encountered 30-40 feet below ground surface. The soils onsite were competent but, under building loads, would not have met settlement and bearing capacity without ground improvement.