Resistance Pier Foundation Applications
Resistance Piers are used primarily for underpinning and the repair of residential and commercial buildings, retaining structures, and slabs. They can be installed in either interior or exterior locations. They have been used to repair equipment and machinery foundations, warehouse buildings, tower foundations, and more. Special remedial brackets can be connected to either the bottom or side of an existing foundation for repairs. They can also be connected to the sides of round or flat building columns.
Resistance Piers not only stop settlement but they can also be used to raise the structure. This allows them to close cracks and correct other structural flaws resulting from settlement or ground movement.
The design process should involve professional engineering input. Specific information concerning the structure, soil characteristics, and foundation conditions must be evaluated and incorporated into the final design.
Resistance Piers from Intech Anchoring
For Resistance Pier applications, Intech Anchoring supplies the Atlas Resistance Pier, which is a two-stage manufactured product designed specifically to produce structural support strength. First, the pier pipe is driven to a firm bearing stratum; then the lift equipment is typically combined with a manifold system to lift the structure (if required). This procedure provides measured support strength.
Piers are spaced at adequate centers where each pier is driven to a suitable stratum and then tested to a force greater than required to lift the structure. This procedure effectively load-tests each pier prior to lift and provides a measured factor of safety (FS) on each pier at lift.
Workspace is not normally a problem when using Atlas Resistance Piers. They can be installed using portable equipment in an area that measures approximately 3 feet square. The pier may be installed from the interior or on the exterior of the footing.
Pushed Pier Systems History
Although numerous methods and materials have been used throughout the centuries, modern construction methods and practices have mandated the repair and remediation techniques of today’s structures. The use of excavated foundations, footings, walls, and beams—although providing adequate support in some soil conditions—has proven to be less desirable in a multitude of soil and site profiles.
Fill areas, compressible soils, organics, and expansive soils offer a more significant challenge in the long-term stability of foundations. They are an underlying cause of billions of dollars of structural remedial repairs worldwide. The need for deep foundation underpinning systems increased dramatically in the 20th century with the building booms and growth in metropolitan areas.
A substantial advancement was developed and patented by Lazarus White of New York in 1917. White addressed long-term stability issues encountered in previous similar methods by introducing the practice of pre-loading. He termed it “the first or temporary load” encountered from the reaction when pushing the pipe against the structure load to a pre-determined capacity equal to 150% of the required load. This is consistent with the installation methodology ATLAS Resistance® Piers use today.
White also documented theories of the soil “pressure bulb” created at the pile tip, which assumes compression of the soil beyond the periphery of the pile for contributing to “a load in excess of that attributable to the resistance of the area of the end of the pile.”
One early documented adaptation incorporating the use of a steel eccentrically loaded bracket with pushed piles as a load transfer method was revealed in a 1959 patent application by Guy Henry Revesz and Jack C. Steinsberger of Illinois. The method of 150% pre-loading, which was prevalent in White’s patent of 1917, is also a standard criterion in this 1961 patent methodology. Numerous similar patents for pushed or jacked piers surfaced in the 1960s and 1970s, further extending the work of these early pioneers.
To learn more about resistance piers and their applications, contact Intech Anchoring today.
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