A CNC Foundations aggregate pier drilling rig and a front loader coordinate to place crushed aggregate into a borehole. The jobsite is visibly marked by spread-out white gravel, compacted dirt, and active heavy machinery working to stabilize the ground for residential development in Indianapolis.
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Aerial wide shot of the construction site at The Row Housing Development in Indianapolis. Multiple pieces of CNC Foundations equipment, including drill rigs and loaders, are positioned across a long, cleared dirt site. White gravel marks aggregate pier locations, and vehicles line the perimeter, showing an active
Overhead view of CNC Foundations equipment at work: a yellow front loader is seen delivering crushed stone into a borehole while a large drilling rig installs aggregate piers on a dirt construction site. White crushed rock surrounds the area, indicating active ground improvement in progress for The Row Housing Development in Indianapolis.

AGGREGATE PIER INSTALLATION FOR THE ROW HOUSING DEVELOPMENT IN INDIANAPOLIS

  • INDIANAPOLIS, INDIANA

CNC Foundations (CNC) delivered ground improvement services using aggregate piers also known as Vibratory Stone Columns(VSCs) to support the construction of The Row, a 111-unit workforce housing development located just north of Monument Circle in Indianapolis’s Herron-Morton Place neighborhood.

Spanning 32,700 SF and situated on a tight urban site, the project includes 54 market-rate units and 57 workforce housing units. CNC’s fast solution stabilized variable fill soils and enabled the project team to maintain schedule continuity and minimize neighborhood disruption.

  • Owner: Monon Multifamily Partners, LLC
  • General Contractor: Grand Contracting
  • Structural Engineer: CE Solutions
  • Project Timeline: 8 Production Days
  • Project Size: 32,700 sq ft
  • Design Bearing Capacity: 4,000 psf
  • Service: Vibratory Stone Columns – Aggregate Piers
  • Install Numbers: 574 piers at 6,310 linear feet
  • Market Sector: Multi-Family Housing

The developer required a cost-effective foundation system to support multi-family residential loads on a constrained urban site with poor subsurface conditions.
 Coal ash and variable fill soils posed a high risk of differential settlement and construction delays. Traditional deep foundations were not economically viable, and the project demanded a rapid ground improvement method that could meet strict performance requirements.

CNC Foundations delivered a tailored solution while navigating the complexities of a dense downtown setting. With limited laydown space and multiple trades operating simultaneously, precise planning and agile execution were critical. CNC minimized disruption and helped keep the project on schedule.

Subsurface investigations revealed a challenging fill profile unsuitable for direct foundation support. The upper layers included 4–5 inches of asphalt over black sand (coal ash), underlain by sandy silty clay and silty clay fill with variable sand and gravel content. These materials exhibited low shear strength and high compressibility – posing a significant risk for differential settlement.

To address these conditions, CNC Foundations implemented an aggregate pier installation solution. This approach densified the existing fill and transferred structural loads into deeper, more competent bearing soils, delivering improved stability without the need for deep foundations.

CNC Foundations installed over 570 vibratory stone columns totaling over 6,300 linear feet across the site. Using a vibratory flot, stone was placed and compacted in controlled vertical layers from the target depth to the surface, forming high-density aggregate columns that:

  • Improved load-bearing capacity to 4,000 psf
  • Maintained settlement within engineering limits
  • Allowed for fast, low-disruption installation
  • Eliminated the need for costly deep foundations or mass excavation

The project was completed in just eight production days, and post-installation load testing confirmed performance well within engineering limits. CNC’s precision execution helped the general contractor maintain critical path continuity and move seamlessly into vertical construction.