What is a Helical Pile?

If you’re involved in commercial construction, you’re likely familiar with the process of structures rising from the ground. However, what happens below ground, at the foundational level, might be less clear. That’s where helical piles come into play. They are an essential component of underground construction technology, invisibly holding buildings and bridges in place. But what exactly is a helical pile?

Helical piles literally do all the heavy lifting.

Before we delve into the details, let’s cover some basic facts about helical piles. Once you understand what they do, what they’re made of, and how they work, you’ll gain a whole new appreciation for these invisible champions of deep foundations.

What Do Helical Piles Do?

The primary purpose of a helical pile is to provide foundational support for structures of all types and sizes. Similar to traditional pile foundations, helical piles are embedded deep underground to disperse the weight of the structure above them. Multiple piles are installed to create a platform on which a building, bridge, or any large structure can rest.

You may be wondering, what is a helical pile used for? To learn more about the applications and uses of helical piles, visit our deep foundations page.

What Are Helical Piles Made Of?

Most helical piles are made of steel and come in a variety of diameters and gauges to suit different project requirements. They can be round hollow shafts or square solid shafts.

The defining characteristic of a helical pile is the presence of one or more steel screw threads, also known as helical bearing plates, welded onto the shaft. These plates provide downward force as the pile is twisted into the soil. The angle and size of the screw can vary based on the application and soil specifications.

At the head of the pile, there is a shear lug designed to fit machine-driven, rotary hydraulic attachments. The power to rotate the pile comes from small or large excavators, depending on the size of the pile.

For grouted pile applications, a lead displacement plate is fitted onto shaft extensions. This plate pushes the soil aside as the pile is screwed in, creating space for the concrete that follows.*

How Do Helical Piles Work?

The installation process for helical piles involves twisting them into the soil, much like how a corkscrew is twisted into a bottle of wine. As the shaft of each pile disappears below the surface, additional extension segments are connected using bolted couplers and screwed into the soil. This process can result in a single pile that extends hundreds of feet below the ground.

In many cases, the steel pile itself is sufficient to meet the load requirements of the project. However, for more robust deep foundation systems, concrete (grout) can be incorporated. In a grouted column, concrete is continuously poured down the sides of the column, following the displacement plate and encasing the steel shaft. This technique creates a reinforced pillar capable of withstanding extreme compressive, uplift, and lateral forces.

Conte Company has also been involved in the development of the DRIVECAST™ Grouted Soil Displacement Pile, manufactured by HUBBELL-CHANCE®, which incorporates displacement functionality directly into the screw bearing plate.

So, to answer the question, what is a helical pile? We’re happy to answer any other questions you may have. Contact the helical pile experts at Conte Company today to set up a phone call or a meeting.