Caroline Street Residences

Waterloo, Ontario

Geopier Rammed Aggregate Pier® Elements Used to Support 22-Story Residence

  • Owner: Mady Developments Corp.
  • General Contractor: Van Mar Contractors
  • Geotechnical Engineer: SOLA Engineering
  • Structural Engineer: Stephenson Engineering
Client's Challenge

The challenge on this project was addressing the differential settlement between a 22-story tower-supported mat foundation and a 3-story podium supported on spread footings. Based on the geotechnical information, as much as 4 – 6 inches (15 to 10 cm) of unreinforced settlement was predicted for the tower’s mat, while 0.5 to 1 inches (1.3 to 2.5 cm) of settlements were expected for the lightly loaded podium.

Subsurface Conditions

Soil conditions consisted of a layer of loose to medium dense silty sand followed by dense to very dense sand and gravel.

Geopier® Solution

In addition to decreasing the expected total settlements from 4 – 6 inches (15 to 10 cm) down to less than 2 inches (5.1 cm) and controlling differential settlement between the two structures, we were able to decrease the planned mat thickness from about 10ft (3 meters) thick to about 5 feet (1.5 meters). This was accomplished through an iterative design process that involved adjusting the pier stiffness values (springs) to match the applied contact stresses, thereby reducing the shear and bending moments in the mat.

Client Testimonial

Geopier worked closely with our design team to improve our soil bearing capacity resulting in significant cost savings to this 22-story building.


Art Van Maren

President VanMar Constructors ON Inc