Helical piers, also known as screw piles, are segmental foundation products that are used to reinforce and stabilize structures of all types and sizes. They work similarly to driven piles but in a much faster and more cost-effective manner.
What is the difference between piers and pilings?
The helix shape of the bearing plates on the end of the shaft transfers the load into the soil in a way that doesn’t puncture or disrupt it like a typical pile. This means that helix piles can be installed in difficult to reach locations, including in areas of poor ground conditions where other pile designs may not be able to penetrate or achieve the desired load capacity.
Helical piles are a reliable product and, when properly designed by an engineer, can reliably satisfy design loads. This is possible due to the empirical relationship between installation torque and axial capacity which is established during testing. However, this method of designing a helix pile is not a replacement for a full geotechnical investigation.
During installation, a pile’s capacity can be tested with a hydraulic jack and beams which is typically called a static load test. During this process, one or more piles are loaded until they demonstrate a consistent and predictable response which is then confirmed with a data log of shaft measurements and torque values. This relationship can then be utilized to monitor pile performance during production and avoid the expense of load tests at each pile location.
In many cases, piles are also tested during construction as part of a pile monitoring program to confirm that they are performing according to the original design specifications. This is especially important for large projects where a geotechnical investigation would be costly and/or impractical to implement.