Patent Application
20050025576
The present invention relates generally to an apparatus and method for supporting above-ground structures and/or repairing structural foundations. More particularly, the invention relates to an apparatus and system that includes a foundation pile segment, or a plurality of corresponding foundation pile segments, having enhanced supporting or underpinning capacity. The invention further relates to a method of support installation or underpinning utilizing such a pile or piles, whereby the pile is driven vertically into the earth.
Foundation pile segments, or simply, foundation piles, are driven into and installed in the earth to transfer thereto, the loads applied to or resulting from above-ground structures such as buildings, slabs, walls and columns. An installed foundation pile obtains its load bearing capacity primarily from two surface areas: the bottom surface and the sidewall surfaces. The bottom surface provides the primary, direct end load bearing capacity. The sidewall surfaces, on the other hand, frictionally engages the adjacent soil to provide frictional surface areas that resist the downwardly directed load.
A foundation pile apparatus according to the present invention is utilized to support an above-ground structure such as buildings, walls, slabs, and columns. The inventive foundation pile includes a generally solid body (e.g., rounded, square or rectangular shaped, cylindrical, etc.) having a top end wall, a bottom end wall and all around sidewalls extending therebetween. In several embodiments, the body of the pile apparatus is precast concrete and further, has a generally rounded shape (i.e., a generally circular cross section). The sidewalls extend between the top end wall and the bottom end wall and has at least one (but, preferably two or more) spiral ridge that extends generally about, the surface of the sidewall. Further, this spiral ridge extends in a generally spiral direction from the top end wall to the bottom end wall. The spiral ridge provides an offset surface that extends generally outward from the surface of the sidewalls. The surface area of this offset surface significantly enhances the load bearing capacity of the pile.
For purposes of the present Description, the term “spiral” or “spirally” is used to refer to a direction in which the ridge traverses both circumferentially and downwardly about the sidewalls of the pile body. In various embodiments of the invention, the spiral ridge may traverse up to or less than one-quarter of the circumference, and even the full circumference or beyond. The spiral ridge may also traverse the full height of the pile body, a distance less than the full height, and/or a distance less than the full height and in between the end walls
In another aspect of the present invention, a method of installing foundation piles for supporting an above-ground structure is provided. The inventive method includes the step of providing a foundation pile apparatus such as that described above. The foundation pile apparatus is driven into unexcavated earth a desired distance and set a desired depth, whereby said offset surface and said end wall support a load on said pile apparatus. Preferably, a downward force is applied upon the foundation pile (e.g., upon a top end wall), whereby the pile apparatus moves downwardly and rotatably into the unexcavated earth. In this driving step, the pile may rotate about ¼ turn for every given downward distance into the earth (wherein the given downward distance corresponds to about the height of the pile). Moreover, in rotating the pile, the spiral ridge preferably loosens the soils adjacent the pile as the pile is driven downwardly into the earth, thereby facilitating and making more efficient the driving step.
These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed descriptions and the drawings.
Each of
Referring to
The foundation pile 101 of
In other embodiments of the invention, the foundation pile may be constructed of materials such as wood, metal, epoxy, or other materials generally known and used for foundation pile construction. In further embodiments, the foundation pile may take on other shapes including a generally square or rectangular configuration or a generally tapered or bell-shaped form. The shape of the concrete pile 101 in
In one unique aspect of the invention, the preferred concrete pile 101 is precast in a special-shaped mold. As illustrated by
With reference to
Because of the 45° angle of the spiral ridge 109, the round shaped pile 101 may be driven vertically downward into the unexcavated earth in a manner that produces a quarter turn (or 90° turn) with each distance equaling the height of the pile. In this way, a concrete pile 101 having a height of 12″ and a diameter of 6″ rotates about ¼ turn or 90° or for every 11-12″ penetration into the soil. Moreover, the spiral ridge 109 provides a facilitating function during installation of the pile 101. Specifically, as the pile 101 is impacted by a generally vertical downward force (i.e., from a hammer or hydraulic ram) on the top end wall 105, the spiral ridge 109 causes the soil immediately in front of the offset surface 111, and adjacent the sidewall 113 and bottom end wall 107, to loosen. In this way, the resistance of the soil to downward movement of the pile 101 into the earth is reduced. It has been observed by the Applicant that a concrete pile 101, such as the embodiment depicted in
In addition to the benefit of driving a pile deeper and faster into the earth, the inventive pile also allows for more segmental piles to be installed in one location. Accordingly, a system of such piles provides even greater support to the above-ground structure.
It will be apparent to one skilled in the art that other dimensions of the pile apparatus, of concrete or other material, may be obtained as required. For example, concrete piles may be made shorter and smaller than the 12″ high and 6″ diameter piles depicted in the Figures. It will also be apparent to those skilled in the art that there may be certain practical limitations, i.e., strength, to the size and dimensions of the pile design.
Now also referring to
A system of corresponding or segmental piles further illustrates the advantage provided by the inventive foundation pile. In such systems and installations, it is not uncommon to drive fifteen foundation piles into the earth. Thus, in accordance with the inventive method, fifteen piles may be driven to provide an additional end bearing surface capacity of 180 square inches (12 square inches×15 piles). As a result, in a method according to the invention, the series of piles may be driven deeper into the earth and provide greater end bearing capabilities. Moreover, with the greater depth, greater stability may be achieved because the concrete piles or at least more of the concrete piles may be driven into non-weather affected zones of the earth. Still further, with piles driven into the earth, the system of piles provides greater frictional surface wear (because of the additional piles). These are just some of the important advantages and benefits afforded to one employing the method according to the invention and the pile apparatus according to the invention.
The systems, apparatus, and methods described herein are particularly adapted for installation of a pile segment in a system of piles, e.g., segmental piles, and preferably, concrete or wooden piles. However, it would be apparent to one skilled in the relevant mechanical or structural art upon reading the Description and viewing the accompanying Drawings, that the various aspects of the invention are also applicable to other structural or foundation support systems. For example, the foundation pile and method of installing same, may be adapted for single pile installations or multiple installation (e.g., segmental piles). Moreover, the foundation pile segment may be constructed of materials other than concrete or wood, may take on other shapes such as square, rectangular, or bell-shaped. Further yet, the piles may have more than two spiral ridges or a single spiral ridge that traverses the entire circumference of side wall one or more times.
Thus, the foregoing description is presented for purposes of illustration and description, and is not intended to limit the invention to the forms disclosed herein. Consequently, variations and modifications commensurate with the above teachings and the teaching of the relevant art are within the spirit of the invention. Such variations will readily suggest themselves to those skilled in the relevant structural or mechanical art. Further, the embodiments described are also intended to explain the best mode for practicing the invention, and to enable others skilled in the art to utilize the invention and such or other embodiments and with various modifications required by the particular applications or uses of the invention. It is intended in the appended claims be construed to include alternative embodiments to the extent that is permitted by prior art.
