This five-story apartment complex constructed on Lake Jonathan Flats in Chaska (MN) required a design that reduced the lateral soil load against the east side of the building’s 20-foot-tall pre-cast-concrete foundation wall.

The north side underground parking garage is under extra stress because 270 feet away is highway 41, which runs parallel to the building and which is 45 feet above the building’s grade.

Engineers designed for a total depth of 14 feet of TDA (Tire Derived Aggregate) to be backfilled against the 12-inch-thick wall. TDA reduces the lateral load and helps control drainage and moisture running from Highway 41 to the nearby lake.

Additional benefits of TDA include the following:

• Reduced Lateral Load: 1/2 the lateral load of soil, which can reduce retaining wall costs.

• Lightweight: 1/3 weight of soils (600 spare pounds per loose volume cubic yard).

• Interlocking: Creates a foundation for overlying structures.

• Permeability: Up to 50% better drainage than gravel.