Project
Sector – Parking Structure
Location – Chicagoland / Orland Park, Illinois
Application(s) – Aggregate Piers / Vibratory Stone Columns (VSCs) for Ground Improvement

Description
A 5 story mixed-use building (parking garage and restaurant) constructed in Orland Park. The building will be used for parking and a future restaurant.

Requirements & Challenges
Existing uncontrolled fill extended 15 to 18 feet below existing grade, the cohesive fill was variable in consistency, containing concrete, brick, and asphalt pieces and layers. An additional 2 to 3 feet of buried topsoil and/or marginal strength soils were often found underlying the fill materials. These materials were deemed unsuitable for foundation support.
The soils would need to be improved to 7,000 psf and only allowing for 1 inch total and ½ inch differential settlement.

Solution
The geotechnical engineer of record offered three different solutions;
Drilled Piers found to be cost prohibitive
Remove and replace the existing fill found to be cost prohibitive
Install Vibratory Stone Columns to improve the uncontrolled fill.
Helitech was hired to design and install their Vibratory Stone Column system.

Results
Helitech’s design and methods of constructing Vibratory Stone Columns allowed for a cost-effective solution and allowed the general contractor to meet their schedule. Testing on a sacrificial and production piles confirmed the design and soil parameters used in the design.

Related Case Studies