Fair Oaks West Apartments Piering

The Challenge

Stabilizing 16 apartment buildings built over partially submerged parking garages.

The client faced a significant challenge with sixteen apartment buildings built over partially submerged parking garages from the 1970s. These buildings were experiencing minor settlement due to the underlying unstable soils. In addition to the settlement issue, the project site had a low head clearance of just 6.6 feet, severely limiting the type of equipment that could be used for foundation repair. The soil profile was another complication, as it consisted of variable layers of sand, dense clayey sand, silt, and gravel, making it difficult to predict the load-bearing capacity in certain areas. These combined factors required a specialized approach to stabilize the buildings while working within tight spatial constraints.

Key Facts

The Solution

Customized helical pile installation to meet load and clearance requirements.

To address these complex challenges, engineers deployed a tailored solution using helical piles and small footprint installation equipment. The low ceiling height required specialized machinery capable of fitting within the restricted space, which allowed the team to efficiently carry out the installation. A total of eight vertical piles and four battered piles were installed per bay, ensuring that each structure would be supported adequately across varying soil conditions.

The vertical piles used 8″, 10″, and 12″ helix bearing plates, designed to handle loads of 40 Kips. For the battered piles, two configurations were used: 10″, 12″, and 14″ helix plates for the first and 16″, 14″ helix plates for the second, each designed to bear a required load of 70 Kips.

Additionally, a tension load test was conducted on one of the battered piles to ensure the stability and effectiveness of the installation. This multi-faceted approach provided both the strength and precision required to stabilize the buildings.

The Impact

16 weeks to stabilize 16 buildings with precise pile installation.

The project’s impact was significant, with all sixteen buildings successfully stabilized within a structured timeline. For the larger buildings, which had four bays each, 48 piles were installed per structure, while the smaller buildings, which had two bays, required 24 piles each. Despite the complex conditions, the team completed one building per week, ensuring that the entire project was finished in just 16 weeks. The timely and precise installation of the piles not only stabilized the buildings but also minimized disruptions, ensuring that the client’s needs were met without extended downtime or additional costs.