When you need foundation repair in Charlotte, North Carolina, you look for a trusted name – Tar Heel Foundation Solutions. We take pride in using the latest and most up to date products on the market, which allows us to stay at the top of our game and keep your home on top of its stable foundation. We are a preferred installer of ECP, Earth Contact Products. The most commonly used item is the Model 300 steel pier for underpinning repairs. It allows your home to rest on a stable footing and hold up to its proper load-bearing standards. The pier is designed to drive deep into the soil to support structures from the interior and exterior of the foundation. It bypasses all of the active soils to do so. It is the leader of steel piering systems and is quickly becoming well-known for being the strongest and deepest driving pier system around.
This pier is an end-bearing pier, which means that it does not rely on any type of friction to produce the support that it is installed on. All piers are load tested before being installed to assure that they meet all standards and will produce the type of support needed for the repair. The design of the pier ensures maximum weight will be supported during and after restoration and load transfer.
The piers are individually driven while the entire structure is restored as a reaction. The friction reduction collar that is attached to the lead section of the pier pipe will allow for an opening in the soil to be created, which in turn reduces the friction and allows for the installer to load test the pier and verify when a firm rock or stratum is reached for maximum stability. High-pressure jacks are attached in many locations around the foundation of the home and maneuvered by a hydraulic manifold. This reduces the load on the individual piers and only allows for the designed working load to be transferred to each pier.
Foundation Push Pier Installation, Step by Step:
1. Site survey: Pier placements are located and the location of underground utilities verified.
2. Excavation: Small excavations are dug for access at each placement location. The space required at the foundation is usually about 3 feet square. (fig 1)
3. Preparation of the foundation: This includes notching the footing (if required) to place the pier bracket under the stem wall, preparing the bearing area under the footing to a smooth and level condition, and adjusting the face of the stem wall to vertical (plumb) at the point of bracket attachment. (fig 1)
4. Utility Bracket Attachment: The utility bracket is secured to the footing using anchor bolts. Attachment of the drive stand and the hydraulic cylinder that is used to force the pier pipe into the soil is mounted on the drive stand. (fig 2)
5. Pier Pipe Installation: The pier pipe is advanced into the soil using the structure as the reaction force with a 10,000 psi hydraulic pump and cylinder combination. The piers may be installed from outside or inside the structure. Pier installation continues until rock or suitable bearing-strata is encountered below the unstable soil near the surface. (fig 2)
6. Load Test: Every pier is load tested by increasing the force on the pier to ensure the rock or bearing-strata will support a load greater than needed to guarantee a factor of safety. Typically an engineer will determine the load of the structure and the desired factor of safety before the load tests are performed. (fig 3)
7. Preparations for Restoration: Once all piers have been installed, load tested, and the installation data at each placement recorded; lifting head assemblies and hydraulic lifting rams are placed on the piers. The lifting cylinders are connected with one or more manifolds and operated using a hydraulic pump. (fig 3)
8. Restoration: Under careful supervision, the load is transferred from the existing failing strata under the foundation, to the load tested piers. The structure can be transferred gently and evenly lifted to as close to the original elevation or to the recommendation of the engineer. The nuts at the pier caps are secured at each placement and the lifting equipment is removed. (fig 4)
9. Clean Up: The soil that was excavated at each pier placement is now replaced and compacted. The site is left clean and neat.