Helical piers have a round, steel shaft with screw like (helical) plates that can support many types of structures and are used for foundation leveling. Using a high capacity torque motor, the helical pier is screwed into the ground like a screw into wood. Once the helical pier reaches load bearing strata and achieves it’s engineered capacity, a steel bracket is used to join the foundation wall and the pier together. Next, hydraulic rams are used inside the steel bracket to push down against the top of the pier. This downward force causes the structure to lift. Imagine a jack under a car. As you pump the lever the jack pushes against the ground to lift the car.
Helical piers are primarily used to transfer the weight of a structure through inadequate soils to a deeper load bearing strata. They can also be used to keep a structure from heaving if it is placed on expansive soils. In both situations, a helical pier can be installed before or after construction. Installing helical piers before construction is less expensive so it’s important to have a pre-construction soil test done by a licenced geotechnical engineer. They can tell you if foundation piers will be right for your building site.
Did you know that helical piers have as much capacity in tension as they do in compression? This means that you can pull up on them as hard as you can push down on them.
Helical piers have many other applications:
Energy Industry – Because of the helical pier’s ability to provide tension strength they are used in the energy industry for anchoring telephone & electrical poles and have come in handy for the solar industry as well.Helicals anchor the solar field arrays when wind passes under them creating a sail like effect and causing uplift. The petroleum industry also benefits from the use of helical piers by using them to hold gas lines in the air. A helical pier can lock the large gas lines to the ground which is crucial in cold climates when the soil freezes and causes the ground to heave. Too much ground heave would cause the pipe to bend and break. For this same reason oil fields have begun using helical piers to stabilize oil pumps as they draw crude oil from the earth.
Soil Stabilization – Large retaining walls can have immense soil pressure that, over time, can cause them to lean in, crack and break, or fail entirely. Helical piers can be installed through the wall and into the soil behind it. Like an anchor on a boat, the piers will hold the wall back.
Boardwalks – Boardwalks are installed to allow us to enjoy nature without disturbing fragile ecosystems. Helical piers can be installed with very low impact to these fragile zones.
Helicals have even been used to create unbelievable amounts of soil capacity in Cape Canaveral for NASA space launch pads.
It’s fair to say that there are many applications for helical piers that will still be discovered.
Considering helical piers? Take a look at some of their benefits and advantages!
Can be used in fragile areas.
No overburden or spoils from soil
Environment friendly installation.
Minimal weather delays.
No cure time needed for cement.
Easy removal if necessary
Weight transfer of structure to pier is immediate after installation.
Zero vibrations creates a safe installation next to existing structure.
Access holes are excavated or dug at helical placement points to gain access to the foundation.
Concrete will be notched out on the footing to allow for close placement of the pier to the foundation wall.
Helical Piers are driven to the previously engineered torque capacity. Depth will vary based on the soil under the structure.
Brackets are then placed on top of the pier and will be used to lift the structure.
If possible, the structure will be carefully lifted to it’s maximum practical elevation. Every effort is made during thefoundationleveling process to lift the structure back to its original elevation.
Lastly, access holes are then backfilled and compacted.