Thrasher Foundation Repair uses resistance piers to stabilize and/or lift foundations that have settled and/or moved. The cause of this movement primarily stems from the structure being built over poor or unstable soils. Resistance piers are one of the most commonly used types of piers in and around Kansas City due to the type of soil and structures found in the area. Homes in the Midwest are typically constructed with basements—a heavier type of construction than homes that are found in other areas of the country. Because the resistance pier requires a certain amount of weight to push the pier into the ground, this heavier construction is conducive to the use of resistance piers.
Resistance piers are hydraulically driven, high-strength steel, tubular, end-bearing piles. The pile sizes vary in diameter from 2-2/8” to 4-1/2”, as well as in steel thickness and transfer brackets to accommodate a wide range of load and support conditions.
The steel piles (piers) are driven in connected sections, using the weight and structural integrity of the building to advance the piles to a stable load-bearing stratum. There is a direct correlation between drive force and pile capacity. Drive force is continuously measured during installation to a pre-determined ultimate capacity with a factor of safety from 1.5 to 2X. The drive force measures the end-bearing capacity of the soil, rock and pile. The stiffer the soil, the more drive force required. The predetermined capacity is derived from analyzing and estimating the building’s weight (live loads, dead load and soil loads) and structural strength of the building support components. Pier spacing is determined by a number of influences: weight of structure, capacity of selected pile, soil type, and structural strength of the foundation to determine span limits. By measuring drive force, the capacity of the soil is measured and the pier is continuously tested.