Helical Piles Versus Concrete Push Piles
Some additional questions that I get when working with clients with Foundation Issues are the following:
What is the difference in helical piles versus concrete push piers?
The best way I have learned to explain is we are looking at the difference between a nail and a screw. The push piers are like nails that are being pushed into the ground by the weight of the house, and a helical pile is a bid wood screw that is installed by a hydraulic drive head.
Since the push pier system uses the weight of the house, there is a concern for the safety factor that you get with the piles (meaning there is not much extra capacity on the piles). Also, the depth of the piles is very dependent on the condition of the soils where the piles are being installed.
Concrete piles are friction piles, so they use the friction between the soil and the concrete to obtain the strength to support the house. So, if the soils are wet, they can go deeper than if they are dry. Since most settlement occurs during a drought, or when the soils dry out, they are probably not installed as deep as during the wet season. So, the house has potential to move when the soils get wet and loses it friction coefficient.
As far as a helical, again it is a bid wood screw. Just like a screw, the helical piles, once they are started, actually pull themselves down so they can go deeper than the push piers (since we are not dependent on the weight of the house). We also can use the torque (strength of twisting force) to determine the capacity of the helicals. This also allows us to know what capacity the piles are so we get a higher safety factor to properly support the foundation.
They are also not dependent on the condition of the soils, so if it is wet or dry we can install the piles thru the soils into the stabile soils. We typically install the helical piles to a depth of 28’. Since the helicals have the ability to be installed deeper, this allows us to get higher capacity piles so we have more safety factor.
We have installed and tested piles to a depth of 110’ in NOLA and Load Tested Helical Piles in LA for Grain Silos to 245-kip Ult. Capacity (245,000 lbs. or about 5 loaded semi-trucks).
If you have any questions about foundation repairs or concerns for a foundation problem please call us and we will be glad to assist you.