PILE COUPLING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/843,015, filed September 8, 2006, which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates to a coupling for piles, such as those used to support a boardwalk or a building foundation.

BACKGROUND OF THE INVENTION

[0003] Conventionally, piles are metal tubes having either a circular or a rectangular cross-section. The piles are provided in sections, such as 7-foot sections, that are driven into the ground or, in the case that at least one pile is a helical pile, screwed into the ground. The sections of a rectangular pile are conventionally coupled together as shown in Fig. IA wherein slotted ends of the sections fit together and one or more through-bolts secure the coupling. Fig. IB shows the coupling of circular pile sections wherein an enlarged collar on an end of one section receives the end of the other section and a through-bolt secures the coupling. Fig. 1C shows the coupling of pile sections wherein the end of one pile is swaged to fit over the upper end of a lower pile. Again, the bolts are transverse to the longitudinal axis of the pile.

[0004] In either case, the bolts that secure the coupling are oriented transverse to the axis of the pile. This results in vertical and horizontal slop due to the tolerances required for the clearance holes that the bolts pass through. The horizontal slop or lateral deflection is due to the couplings acting like hinges with each side of each coupling being allowed to take up the slop independently. The slop may be small for each coupling, but adds up to a significant amount when several sections are connected in series. For example, if each coupling of five pile sections connected in series includes about 1/16-

inch of slop, the foundation or platform supported by the pile sections may travel upward as much as 1 /4-inch in a high wind condition or an earthquake event. The horizontal slop in the same situation could be much more. Further, vertical forces on the pile sections apply a shear stress to the transversely oriented fasteners, which tend to be weaker under shear stresses. Also, the through-bolts block the axial bore of the pile thereby preventing the addition of concrete to the center of the pile as well as preventing drilling through the center of the pile.

SUMMARY OF THE INVENTION

[0005] The invention comprises, in one form thereof, a pile assembly including a first pile section and a second pile section, each of the first and second pile sections having a longitudinal axis; a first flange associated with the first pile section and extending in a direction substantially transverse to the longitudinal axis of the first pile section; a second flange associated with the second pile section and extending in a direction substantially transverse to the longitudinal axis of the second pile section; and the first flange being fastened to the second flange to thereby couple the first pile section to the second pile section.

[0006] In another form, the invention includes a method of forming a pile assembly. The method comprises the steps of providing a first pile section and a second pile section, each of the first and second pile sections having a longitudinal axis, a first flange associated with the first pile section and extending in a direction substantially transverse to the longitudinal axis of the first pile section, and a second flange associated with the second pile section and extending in a direction substantially transverse to the longitudinal axis of the second pile section; and fastening the first flange to the second flange to thereby couple the first pile section to the second pile section.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The present invention is disclosed with reference to the accompanying drawings, wherein:

[0008] Figs. 1 A-IC are side views of conventional pile couplings according to the prior art;

[0009] Fig. 2 is a cross-sectional side view of a pile assembly having a pile coupling according to the present invention;

[0010] Fig. 3 is an isometric view of the end of a pile section and flange of Fig. 2;

[0011] Figs. 4A and 4B are end views of pile sections and flanges according to the present invention;

[0012] Fig. 5 is a cross-sectional side view of a pile coupling with internal grout and an inserted rebar cage according to an embodiment of the present invention;

[0013] Fig. 6 is a cross-sectional side view of a pile coupling with a rock socket according to an embodiment of the present invention;

[0014] Fig. 7-9 are cross-sectional side views of pile assemblies having alternative pile couplings according to the present invention; and

[0015] Figs. 10 and 11 are side views of pile assemblies having alternative pile couplings with improved torsion transfer according to the present invention.

[0016] Corresponding reference characters indicate corresponding parts throughout the several views. The examples set out herein illustrate several embodiments of the invention but should not be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION

[0017] Referring to Figs. 2, 3, 4A, and 4B, there is shown a pile assembly with the pile coupling of the present invention. The assembly 10 includes two pile sections 12a and 12b, each of which is affixed to or integral with a respective flange 14a and 14b. Although only portions of pile sections 12a and 12b and one coupling are shown, the assembly 10 may include any number of pile sections connected in series with the coupling of the present invention.

[0018] The flanges 14a and 14b each include a number of clearance holes 16 spaced apart on the flanges such that the holes 16 line up when the flange 14a is abutted against flange 14b. The abutting flanges 14a and 14b are secured by fasteners 18, such as the bolts shown in Fig. 2, or any other suitable fastener. The fasteners 18 pass through the holes 16 such that they are oriented in a direction substantially parallel to the axis of the pile. In one embodiment, shown in Fig. 4A, the flange 14 includes six spaced holes 16. In another embodiment, shown in Fig. 4B, the flange 14 includes eight spaced holes 16. The eight-hole embodiment allows more fasteners 18 to be used for applications requiring a stronger coupling while the six-hole embodiment is economically advantageous allowing for fewer, yet evenly- spaced, fasteners 18.

[0019] In a preferred embodiment, the flanges 14a, 14b are in each in a plane that is substantially transverse to the longitudinal axis of the pile sections 12a, 12b. Particularly, at least one surface, such as the interface surface 15 (Fig. 3) extends in the substantially transverse plane. Further, the flanges 14a, 14b are slender and project a short distance from the pile sections 12a, 12b in the preferred embodiment. This minimizes the interaction of the flanges with the soil.

[0020] The vertical orientation of the fasteners allows the pile sections to be assembled without vertical slop or lateral deflection. Thus the assembled pile sections support the weight of a structure as well as upward and horizontal forces, such as those caused by the structure moving in the wind or due to an earthquake. Further, because the fasteners are vertically oriented, an upward force is applied along the axis of the fastener. Fasteners tend to be stronger along the axis than under shear stress. ^"

[0021] In a particular embodiment, the pile sections 12a and 12b are about 3 inches in diameter or greater such that the piles support themselves without the need for grout reinforcement, though grout or another material may be used for added support as desired. Since the flanges 14a, 14b may cause a gap to form between the walls of the pile sections 12a, 12b and the soil as the pile sections are driven into the soil, one may want to increase the skin friction between the pile sections and the soil for additional support capacity for the pile assembly 10 by adding a filler material 20 to fill the voids between the piles and the soil. The material 20 may also prevent corrosion. The material 20 may

be any grout, a polymer coating, a flowable fill, or the like. Alternatively, the assembly 10 may be used with smaller piles, such as 1.5 inch diameter pile sections, which may be reinforced with grout. The pile sections 12a, 12b may be any substantially rigid material, such as steel or aluminum. One or more of the pile sections in the assembly 10 may be helical piles.

[0022] In a particular embodiment, the pile sections 12a, 12b are tubes having a circular cross-section, though any cross-sectional shape may be used, such as rectangles and other polygons. A particular advantage of the present invention over conventional pile couplings is that the couplings in the assembly 10 do not pass fasteners 18 through the interior of the pile tube. This leaves the interior of the assembled pile sections open so that grout or concrete may be easily introduced to the pile tube along the length of all the assembled pile sections. Further, a reinforcing structure, such as a rebar cage that may be dropped into the pile tube, may be used with the internal concrete. Fig. 5 shows such a cage 40 with internal grout 42 providing a particularly robust pile assembly 10.

[0023] In a further particular embodiment, the invention is used in conjunction with a rock socket. As shown in Fig. 6, the rock socket 50 is formed by driving the pile sections into the ground and assembling them according to the invention until the first pile section hits the bedrock 52. A drill is passed through the pile tube to drill into the bedrock 52, forming hole 53, and then concrete 54 is introduced into the pile tube to fill the hole in the bedrock and at least a portion of the pile tube. This provides a strong connection between the assembled pile sections and the bedrock 52.

[0024] In an alternative configuration of the pile assembly 10, the flanges 14a, 14b are welded to the outer surface of the respective pile sections 12a, 12b as shown in Fig. 7 as opposed to the ends of the pile sections as shown in Fig. 2. This allows the pile sections 12a, 12b to abut one another and thus provide a direct transfer of the load between the pile sections. In a further alternative configuration, an alignment sleeve 30 is included at the interface of the pile sections 12a, 12b as shown in Fig. 8. The alignment sleeve 30 is installed with an interference fit, adhesive, equivalents thereof, or combinations thereof. The alignment sleeve 30 may be used with any of the embodiments described herein.

[0025] A pile assembly 1 10 having an alternative coupling is shown in Fig. 9. The assembly 110 includes pile sections 112a and 112b having integral filleted flanges 114a and 114b. The fillets 115a, 115b provide a stronger coupling and potentially ease the motion of the pile sections through soil. Similarly to the previous embodiments, the flanges 114a, 114b include several clearance holes for fasteners 18, and the assembly 110 may be coated with or reinforced by a grout or other material 20.

[0026] In a further alternative embodiment shown in Figs. 10 and 11, the pile assembly 210 includes a coupling between the pile sections 212a, 212b with torsion resistance. In Fig. 10, the flanges are omitted for simplicity. The pile sections 212a, 212b include respective teeth 260a and 260b that interlock to provide adjacent surfaces between the pile sections 212a, 212b that are not perpendicular to the longitudinal axis of the pile sections. (While teeth having vertical walls are shown, teeth with slanted or curved walls may be used.) The teeth 260a, 260b may be integrally formed with the respective pile sections 212a, 212b. Alternatively, the teeth may be affixed to the respective pile sections. In Fig. 11, the flanges 214a, 214b are shown with respective interlocking teeth 262a, 262b. The teeth 260a, 260b may be integrally formed with the respective flanges 214a, 214b. Alternatively, the teeth may be affixed to the respective flanges. The flanges 214a, 214b may be used with pile sections 12a, 12b according to the first embodiment, pile sections 212a, 212b having teeth 260a, 260b, or other pile sections. In the previous embodiments, any twisting forces on the pile sections, which would be expected especially when one or more of the pile sections is a helical pile, are transferred from one pile to the next through the fasteners 18. This places undesirable shear stresses on the fasteners 18. The interlocking teeth of the present embodiment provide adjacent surfaces between the pile sections that transfer torsion between the pile sections to thereby reduce the shear stresses on the fasteners 18.

[0027] It should be noted that the manifold connections in the above-described embodiments each provide a continuous plane along the length of the assembled pile sections allowing for neither lateral deflection nor vertical compression or lift. It should be further noted that features of the above-described embodiments may be combined in part or in total to form additional configurations and embodiments within the scope of the invention.

[0028] While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims.