Case Study: How USS Installed Helical Piles & Resistance Piles at College Hill Townhomes

It often takes more than one tool to get the job done.

Here at United Structural Systems of Illinois, Inc., we’re certified foundation repair experts and use whatever equipment or methods are needed.

Read this case study to learn how we helped repair townhome foundations using helical piles, resistance piles, retaining walls, and drainage systems.

Background on College Hill Townhomes

This residential case study will focus on two existing four-unit townhome buildings on College Hill Circle in Schaumburg, Illinois.

USS was contacted by the owners to assist with structural foundation failure. Out of the entire subdivision, the two townhome buildings were closest to the water retention.

The original multi-tiered wooden retaining walls were damaged and failing structurally. They could no longer support the soil load, which caused erosion and settlement toward the retention area.

Over time, the foundations began to sink vertically and the buildings moved. This caused incredible structural damage which we needed to fix before it was too late.

Using Helical Piles & Resistance Piles to Secure the Foundation

When we arrived on the job, we knew the first priority was to stabilize the sinking walls. Our first step was to excavate the east foundation walls.

Then, we installed Titan SP-90 galvanized resistance piers to underpin the buildings. This would prevent the foundations from sinking or settling any further. We drive the resistance or push pier into a firm-bearing stratum and test each load.

Once the buildings were secure, our next step was to remove the damaged wooden retaining walls and cut the soil back. We installed a grid pattern of helical piles into the excavated soil slope. The helical pile installation was done at an angle and driven to the proper soil torque.

Four-inch wire mesh was rolled over the face of the exposed soil slope, and we used steel transition plates to tighten the wire mesh down. The wire was held down by the helical piles.

At that point, we were ready to shotcrete the area to ensure the soil would be permanently held in place. The townhomes were no longer at risk for future settlement and we could rebuild the retaining walls using blocks and installing a proper drainage system. 

Project Results

This project involved repairing the sinking townhome foundations and the retaining walls which caused the damage in the first place.

The USS team installed 1.5-inch square shaft helical piers for the tie-back system. Each of them was galvanized to protect against the elements, and the helical pier installation was in an 8-inch, 10-inch, and 12-inch flight pattern.

We advanced the piles between 14-21 feet from the soil cut line, and they were installed into the ground at an approximate 15-degree banter under the foundation.

The repair was a resounding success and, once completed, it was then safe for people to continue living in the townhomes. Furthermore, the new retaining wall and drainage system would prevent future erosion and foundation sinking.

Helical Pier Foundation Installation

Does the foundation damage we described in this case study sound familiar? Reach out to us for help with repairing failing residential foundations.

Call us today at 847-382-2882 if you have any questions about helical piles or push piers, or if you’d like to schedule a free consultation.