Tuesday, September 8th, 2015
What exactly is a Push Pier?
A Push Pier, or resistance pier, should be made of hollow round steel and is driven by hydraulic pressure deep into the soil to an engineer designed pressure. These piers act as “legs” to add more load bearing capacity for structures which have settled due to unstable soil conditions. The weight of the structure to be supported provides the resistance needed to drive the piers to competent load bearing soil or to bedrock. Push piers require much less intrusive equipment than helical piles and can be installed on the exterior or interior of the structure. Push piers also provide the opportunity to stabilize your home and/or lift it back towards its original position, often closing cracks and improving the operation of doors and windows.
How does a Push Pier work?
First, soil is removed from the area where the pier will be driven to expose the concrete footing that supports the weight of the structure. Next, the footing is shaped so that a steel bracket will fit tightly under the footing. Then the first section of the pier is driven hydraulically through a hole in the bracket with subsequent pier sections being added until the design pressure is reached or the structure reacts to the drive pressure by lifting. The weight of the home is now transferred through the pier to competent load bearing soil below and a lift can be attempted to bring the home back towards its original position.
When to use Push Piers
Because the piers are load tested as they are driven, which means they can be driven until the structure reacts to the pressure, this option is better if soil conditions are unknown. Additionally, less intrusive equipment may be required resulting in less disruption to the area surrounding the structure.
When NOT to use Push Piers
If the weight of the structure to be supported is not heavy enough to provide enough resistance to push the piers to competent load bearing soil or bedrock, then helical piles are a better choice.