Meadows of Aurora Phase 3

The wish of anyone constructing a building, is to have good soil on their site. When site soils are of good quality, it allows for conventional and cost-effective shallow foundations. Shallow foundations are the favourite, being quick and easy to construct. Unfortunately, the conditions for shallow foundations aren’t always readily available, and then the site can easily become a “bad soil” site. As good developable land becomes rarer, these bad sites are increasingly the only targeted sites for development. Ground improvement, however, can make the difference between an unusable site and a usable one for developers to build on when encountering these bad soil sites.

But as we all know, life isn’t black and white, and neither are site soils. What if your site is only half bad? That was the story of a developer we worked with in Aurora, Ontario, that was looking to construct the third phase of a senior living community. After completing a geotechnical investigation, it was revealed that the six-story structure had a soft clay challenge on a portion of the building. Dropping footings by 3-4 m below conventional depths, and caissons were being seriously considered for use on the half of the building that presented the soil challenge.

Anytime a building, or any structure for that matter, is built, that structure is going to bear down on multiple soil types or foundation types; it is critical to evaluate differential settlement. How will the variable portions of the site ultimately react under load? Buildings are very heavy, and this mass always causes some settlement, but it is crucial that this settlement happens as evenly as possible to allow the structure to settle uniformly and avoid structural damage.

Deep foundations and dropping footings well below conventional depths were expensive alternates, so, ultimately, Geopier Rammed Aggregate Pier® (RAPs) elements were selected as the best solution that could still easily control critical differential settlement between the good and bad portions of the site soils. The Geopier GP3® RAP system was used on the poor soil portion of the site with elements installed up to 8 m below foundations to improve the ground to provide 300 kPa SLS bearing for foundations.  

The ground improvement systems used by GeoSolv on challenging soil sites, like those under Meadows of Aurora Phase 3, help to reduce overall project costs, help to mitigate risk, cut timelines, and keep more of the soil on-site, reducing environmental concerns. By avoiding the traditional methods of dig- and-replace or deep foundations, the carbon footprint and environmental impact of any project are significantly reduced. GeoSolv techniques can be as little as 1/20th the carbon footprint of a deep foundation system. Furthermore, these advantages can still be realized even if only a portion of the site consists of poor soils, and this has the potential to make ground improvement even more cost-effective.

Alex Szot is a Pre-Construction Engineer at GeoSolv. He holds a Bachelor of Applied Science degree in Civil Engineering from the University of Toronto and is a practicing member of the Association of Professional Engineers of Ontario. Prior to joining GeoSolv, Alex worked in Geotechnical consulting and construction. If you have any questions for Alex, he can be reached anytime at alex@geosolv.ca