Patent Application
20090110488
The present invention relates generally to foundation piles and more particularly to methods for joining the adjacent ends of two or more coaxially disposed foundation piles.
A foundation pile (also referred to herein simply as a pile or piling) is an elongated beam that is driven deeply into the ground, often under water, in a substantially vertical manner. In this capacity, a foundation pile is commonly used as a support member (i.e., a load carrying element) for various types of structures, such as buildings, piers, docks and bridges.
Pilings are traditionally constructed out of wood, concrete or steel. However, it has been found that wood pilings tend to rot and steel pilings tend to rust when utilized in a marine environment. The rotting and rusting of such pilings not only detracts from their natural aesthetic value but also compromises their structural integrity. As a consequence, wood and steel pilings that are habitually exposed to moisture often require significant maintenance and/or replacement, which is highly undesirable.
Accordingly, composite pilings are well known and widely used in the art as support members in marine environments. For example, in U.S. patent application Ser. No. 11/184,722 to Everett A. Pearson et al., which is hereby incorporated by reference, there is disclosed a tubular composite pile which includes a fiberglass laminate comprising a plurality of fiberglass type layers and an impervious tube array. The tubular composite pile additionally includes plastic inner and outer skins and a resin injected into the laminate. As can be appreciated, this type of composite pile is characterized as having (i) exceptional shear, stiffness, and strength properties, (ii) an outstanding damage tolerance, and (iii) a relatively light overall weight, all of which are highly desirable.
Tubular composite pilings of the type as described above are typically manufactured in a wide variety of different diameters (e.g., 10, 12, 14 and/or 24 inches in outer diameter), thicknesses and lengths. In this manner, the properties of each piling (e.g., strength, stiffness) can be customized to meet the particular need of the customer which, in turn, serves to minimize costs, which is highly desirable.
In certain applications, the upper portion of the ground into which a piling is driven is relatively loose and unstable. As a result, in these circumstances, a piling of considerable length (e.g., an 60 foot piling) is required to ensure proper foundational support. Although a longer composite piling can be readily constructed by a piling manufacturer, it has been found that the transport of such a piling is rather difficult in nature.
As a result, it is well known in the art for pilings of considerable length (e.g., pilings greater than 40 feet in length) to be constructed and shipped as a plurality of shorter individual piles which have identical dimensions in lateral cross-section. Once received at or near its intended place of use, the plurality of individual piles are coaxially joined together in an end-to-end relationship through a multi-stepped splicing process.
One splicing process which is well known in the art involves the creation of a rigid tubular splice which is used to join the ends of a pair of piles. The splice is typically machined as a shortened, unitary piece which has a fixed outer diameter that is approximately equal to the inner diameter of the pair of piles. As part of the splicing process, an adhesive (e.g., glue) is applied to the inner surface of each pile at one of its ends. Each end of the splice is then forceably urged into the adhesive coated end of a corresponding pile. As can be appreciated, the frictional and adhesive-based engagement of the outer surface of the splice with the inner surface of each pile serves to permanently join the pair of piles together in an end-to-end relationship.
Although well known in the art, the above-described pile splicing process suffers from a couple notable shortcomings.
As a first shortcoming, the above-described pile splicing process is relatively labor intensive and time-consuming. Specifically, it has been found that the step of driving each end of the rigid splice into the adhesive coated end of a corresponding pile requires a considerable amount of force.
As a second shortcoming, the above-described pile splicing process does not suitably allow for manufacturing tolerances. Specifically, if the splice is not properly dimensioned in such a manner so as to make uniform contact against the inner surface of the pair of joined piles, the adhesive layer may be inadequately applied between the splice and the pair of piles, thereby compromising the structural integrity of the spliced piles.
It is an object of the present invention to provide a novel method of splicing a pair of foundation piles.
It is another object of the present invention to provide a method of the type as described above which is neither labor intensive nor unduly burdensome.
It is yet another object of the present invention to provide a method of the type as described above which yields a pile assembly with exceptional axial stiffness and strength.
Accordingly, there is provided a method of splicing first and second tubular foundation piles, the first and second foundation piles having equal inner and outer diameters, each of the first and second foundation piles including an inner surface, an outer surface, a first end and a second end, the method comprising the steps of (a) providing a tubular splice that is constructed of a resilient material, the tubular splice including an inner surface, an outer surface, a first end and a second end, the outer diameter of the tubular splice being approximately equal to the outer diameter of each of the first and second foundation piles, the tubular splice being shaped to define a longitudinal slit which extends the entirety of the length of the splice, (b) applying a radially inward compressive force to the splice which renders the outer diameter of the splice less than the inner diameter of each of the first and second foundation piles, (c) coating an adhesive to the inner surface of the first foundation pile at its first end and to the inner surface of the second foundation pile at its first end, (d) inserting the first end of the compressed splice into the first end of the first foundation pile, (e) displacing the second foundation pile such that the second end of the compressed splice inserts into the first end of the second foundation pile, and (f) withdrawing the radially inward compressive force from the splice.
Various other features and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings which form a part thereof, and in which is shown by way of illustration, an embodiment for practicing the invention. The embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.
In the drawings wherein like reference numerals represent like parts:
a)-(h) are a series of fragmentary, front perspective views which are useful in understanding the method of the present invention of joining a pair of foundation piles using a splice, a removable cinch strap and an adhesive; and
Referring now to
For purposes of simplicity only, the splicing process of the present invention is described in detail herein in connection with a pair of uninstalled foundation piles. However, it is to be understood that the splicing process of the present invention could be similarly implemented when one of the pair of foundation piles is at least partially installed (i.e., vertically driven into ground) without departing from the spirit of the present invention.
Foundation pile 11 is represented herein as being in the form of an elongated, tubular member which includes an inner surface 11-1, an outer surface 11-2, a first end 11-3 and a second end (not shown). Similarly, foundation pile 13 is represented herein as being in the form of an elongated, tubular member which includes an inner surface 13-1, an outer surface 13-2, a first end 13-3 and a second end (not shown).
Each of foundation piles 11 and 13 is preferably constructed out of a rigid, durable and lightweight composite material. For example, each of foundation piles 11 and 13 may be constructed out of the fiberglass-based composite material described in U.S. patent application Ser. No. 11/184,722 to Everett A. Pearson, et al. However, it is to be understood that the method of the present invention could be utilized to splice together foundation piles which include alternative types of materials, such as carbon-fibers and/or steel, without departing from the spirit of the present invention.
As defined herein, use of the term “foundation pile” relates to any elongated, hollowed, load carrying element which is vertically driven into ground, such as a dock piling, utility pole, flagpole, mast or the like.
Foundation piles 11 and 13 are preferably identical in lateral cross-section (i.e., have equal inner and outer diameters). Accordingly, when joined end to end in the manner set forth below, foundation piles 11 and 13 together create a single pile assembly which has a constant outer diameter along the entirety of its length, which is highly desirable.
To facilitate the splicing process, the separate foundation piles 11 and 13 are preferably held horizontally, end-to-end, in coaxial alignment with one another, as shown in
As can be seen in
As will be described in detail below, slit 16 enables the outer diameter DO of rigid splice 15 to be substantially reduced upon the application of a significant compressive force. Furthermore, upon the removal of said compressive force, splice 15 is constructed to resiliently expand back to its original dimensions in lateral cross-section (most notably, to its original outer diameter DO).
Splice 15 is preferably formed by cutting a length of either of foundation piles 11 and 13 (or, in the alternative, a pile identical in lateral cross-section with piles 11 and 13). With the length of tubing separated from the pile, slit 16 is formed into the length of tubing using any suitable cutting instrument.
It should be noted that the foundation pile from which splice 15 is formed may include an outer protective coating (e.g., polyethylene terephthalate (PET), polypropylene, polypropylene terephthalate (PTT) or the like). In this case, it is preferred that any outer protective coating present on splice 15 be removed.
It is preferred that the length L of splice 15 be approximately three times the outer diameter DO of the foundation piles 11 and 13 to be joined together. Accordingly, in order to effectively splice a pair of foundation piles 11 and 13 each of which has an outer diameter DO of approximately 10 inches, it is recommended that the splice 15 used to join said piles has a length of approximately 30 inches. Similarly, in order to effectively splice a pair of foundation piles 11 and 13 each of which has an outer diameter DO of approximately 12 inches, it is recommended that the splice 15 used to join said piles has a length of approximately 36 inches. Further, in order to effectively splice a pair of foundation piles 11 and 13 each of which has an outer diameter DO of approximately 14 inches, it is recommended that the splice 15 used to join said piles has a length of approximately 42 inches.
Having formed splice 15 in the manner set forth above, splice 15 is compressed radially inward until its outer diameter DO is slightly less (e.g., approximately 0.25 inches) than the inner diameter DI of each of foundation piles 11 and 13, as shown in
As mentioned briefly above, the particular width W of slit 16 is calculated based upon the degree of radial inward compression required so that splice 15 can be telescopingly inserted into piles 11 and 13. For example, to compress splice 15 to the degree necessary that its outer diameter DO is approximately 0.25 inches less than the inner diameter D1 of each of foundation piles 11 and 13, the width W of slit 16 is preferably approximately 4 inches.
After splice 15 is radially compressed in the manner set forth above, inner surface 11-1 of foundation pile 11 is uniformly coated with an adhesive 19 at first end 11-3, as seen most clearly in
It should be noted that inner surfaces 11-1 and 13-1 are preferably cleaned prior to the application of adhesive 19 to maximize bonding properties.
It should also be noted that adhesive 19 is not limited to any particular composition. Rather, it is to be understood that adhesive 19 represents any bonding agent which is well known in the art, such as epoxy, thermosetting resin, synthetic foam, acrylic adhesive, and thickened vinyl ester. Preferably, the particular composition of adhesive 19 is dependent upon the type of materials which are used to form foundation piles 11 and 13 (i.e., an adhesive with optimal adhesive properties in relation to piles 11 and 13).
With adhesive 19 applied to foundation piles 11 and 13, first end 15-3 of compressed splice 15 is inserted into first end 13-3 of pile 13, as shown in
With splice 15 positioned within foundation piles 11 and 13 in the manner set forth above, cinching strap 17 is removed. Due to its resilient construction, splice 15 expands radially outward upon the removal of strap 17, as shown in
Having removed strap 17, foundation piles 11 and 13 are preferably pushed together by any suitable machine to minimize any gaps present therebetween, as shown in
At this time, adhesive 19 is allowed to cure (e.g., by waiting a pre-determined period of time). Once adhesive 19 cures, the splicing process is completed. As a result, foundation piles 11 and 13 are permanently coaxially joined together in an end-to-end relationship so as to yield a single, elongated foundation pile assembly 23 which has a constant outer diameter DO along the entirety of its length, as seen most clearly in
As can be appreciated, the above-described method of splicing a pair of foundation piles 11 and 13 introduces a number of notable benefits.
As an example, because splice 15 expands radially outward upon the release of band 17, adhesive 19 is spread out in a thin, even and broad manner between splice 15 and foundation piles 11 and 13. As a result, the strength of the foundation pile assembly 23 at the juncture of piles 11 and 13 is maximized, which is highly desirable.
As another example, splice 15 ensures that foundation piles 11 and 13 are permanently joined in coaxial alignment with one another which, in turn, serves to maximize the strength of the resultant foundation pile assembly 23, which is highly desirable.
The embodiment shown of the present invention is intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to them without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined in the appended claims.
