Wide view of CNC Foundations’ rigs and excavator on-site at the Northpoint Blvd project, installing aggregate piers under a clear blue sky.
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Close-up of gravel being poured into a CNC-branded hopper during the aggregate pier installation process at the Northpoint Blvd site.
Two CNC crew members in safety vests and hard hats reviewing operations on-site, with aggregate pier equipment visible in the background.
Multiple CNC rigs installing aggregate piers simultaneously, supported by loaders and telehandlers feeding stone into the hoppers.

GROUND IMPROVEMENT USING AGGREGATE PIERS AT ILLINOIS DISTRIBUTION CENTER

  • PONTOON BEACH, ILLINOIS

CNC Foundations (CNC) delivered ground improvement services using vibratory stone columns (aggregate piers) to support a 1.07 million-square-foot data warehouse project in Pontoon Beach, Illinois.

The solution offered a preemptive approach to stabilize compressible clay soils, improve load-bearing capacity, and accelerate the construction timeline. By strengthening the soil matrix, CNC helped ensure long-term structural performance and a smoother path to project completion.

  • Owner: NorthPoint Development
  • General Contractor: Contegra Construction
  • Structural Engineer: Shrink & O’Donovan
  • Project Timeline: 42 Production Days
  • Project Size: 1.07 million SF
  • Design Bearing Capacity: 4,000 psf
  • Service: aggregate piers – vibratory stone columns
  • Install Numbers: 3,400+ aggregate piers at over 98,000 linear feet
  • Market Sector: Distribution Center

The proposed structure required a foundation system capable of supporting heavy industrial loads across a broad project footprint. However, the site’s subsurface conditions, dominated by compressible clays, posed a significant risk of excessive settlement and potential delays. Traditional deep foundation methods were cost-prohibitive, and the project demanded a rapid alternative that could meet strict performance criteria.

Complicating matters further, the site remained active throughout construction, with multiple contractors and trades working in parallel. Coordinating installation logistics, maintaining equipment access, and ensuring timely material deliveries in such a dynamic environment required meticulous planning and field agility. CNC Foundations successfully executed the ground improvement scope with minimal disruption, maintaining schedule efficiency while delivering reliable, engineered performance.

Subsurface investigation revealed fat and lean clays extending through the upper soil profile, underlain by a competent sand layer. These clay soils exhibited low shear strength and high compressibility, making them unsuitable for direct foundation support. CNC Foundations’s engineering team selected aggregate piers to densify the clay matrix and transfer structural loads into the underlying sand stratum.

CNC Foundations installed over 3,400 aggregate piers totaling over 98,000 linear feet using a vibratory flot that compacted aggregate in controlled vertical lifFts from design depth to finished grade.

  • Increased the allowable bearing capacity to 4,000 psf
  • Maintained settlement within design tolerances
  • Allowed rapid installation compatible with active site operations
  • Eliminated the need for deep foundations 

The project was completed ahead of schedule in just 42 production days, and post-installation load testing confirmed deflections well below design limits, validating the system’s performance and efficiency.