Case Study: Helical Piers Installed by USS Support Apple Store’s New Construction

New businesses open every day across Illinois.

Before they can build new offices, stores, or factories, the owners need to order a study of the ground soil to determine whether it’s strong enough to support their planned structure. In some cases, the soil is found to be “unsuitable” and these businesses call us for help.

In this helical piers case study, we’re going to share how we helped the Apple Store move into its new location in Northbrook Court.

Apple Store Background

The Apple Store in Northbrook, Illinois announced in 2017 that it was changing its location to the Northbrook Court. This famous 130-acre mall serves the North Shore suburbs of Chicago and is a popular destination for shoppers.

If you’ve ever shopped in an Apple Store, you probably remember their unique design. The store was going to feature large columns, grade beams, and reinforced footings to support the structure.

Apple said their new store was being designed to showcase current products and support the future unveiling of items not yet on the market.

The existing floor was removed once the renovation started. A geotechnical engineering company tested the soil and determined that it didn’t have the capability to hold the loads required for new footing pads (which would support the columns).

How Helical Piers Secured the New Apple Store

Shortly after it was discovered that the soil under the store couldn’t support the new structural plans, the Apple Store contacted us to install helical piers around its foundation.

United Structural Systems of Illinois, Inc. has been helping clients with residential and commercial buildings since 1995. We’re a certified foundation repair company and we’re proven experts in helical pier installation.

Helical piers are a quick and effective way to secure a foundation over “unsuitable” soil.

They support or resist loads transferred into the pile by any structure. This load can be tension, compression, lateral, or a combination of all three. The pier works like a self-tapping screw or auger.

Helical piles are installed into the ground by a hydraulic-powered drive head typically attached to a mini-excavator or skid steer on a residential scale, or a full-size excavator on larger commercial projects requiring larger helical piles.

Project Results

At Northbrook Court, we excavated each footing pad approximately three feet below the ground. For each new pad location, a series of five helical piles were installed. Overall, we used 51 helical piles to support the Apple Store.

Each helical pile had a 3.5-inch diameter and was galvanized to protect against corrosion and rust. The helical flight pattern used was 10-inch, 12-inch, and 14-inch.

We installed these piles 28 feet deep to secure the Apple Store’s foundation, which required a compression load of 41 kips for the piles. One kip is equal to 1,000 pounds of force.

In the end, our team installed each pile to 83 kips, which doubled the client’s safety factor.

With the helical piers in place and secure, the final step was to pour concrete to encase the helical pile caps. The columns were later installed on each location.

Commercial Helical Piles Installation

Today, thousands of shoppers visit the Northbrook Apple Store each day. Apple doesn’t need to worry about the soil underneath their store because the helical piers are a permanent solution.

USS works with many companies across Illinois looking to construct new facilities or renovate existing structures. Helical piers can also be used on additions to an existing building.

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