Apparatus for Constructing Foundation Pilings

Abstract

Apparatus for making foundation pilings includes a lead section with screw threads, at least one extension section, and a bit carried by the first of the extension sections. The bit slides onto the first, lower end of the extension section and is operable to compress the soil laterally to the extension sections and form a lateral groove in the soil. Grout fills the annular region of the hole bored by the apparatus including the grooves for lateral stability. Each extension section is formed to fit into the next one and to be secured to it by lateral bolts. The bolt heads prevent the bit from moving vertically as the lead section advances into the soil. Bits may be added to increase the size of the opening bored.

Claims

1. A foundation piling, comprising: (a) a lead section having a first end and a second end opposing said first end, said first end being pointed and said second end having a pair of opposing holes formed therein; (b) an extension section having a first end and a second end opposing said first end, said first end of said extension section operable to receive said second end of said lead section and having a first pair of opposing holes formed therein, wherein said first pair of opposing holes in said first end of said extension section is registrable with said pair of opposing holes of said second end of said lead section when said second end of said lead section is received in said first end of said extension section; (c) fasteners extending through said first pair of opposing holes of said first end of said extension section and said pair of opposing holes of said second end of said lead section when said first pair of opposing holes of said first end of said extension section are in registration with said pair of opposing holes of said second end of said lead section; (d) a bit carried by said first end of said extension section and prevented from moving from said first end of said extension section toward said second end of said extension section by said fasteners, said bit including (i) a cylindrical pipe, (ii) a coupler welded to said cylindrical pipe, and (iii) teeth welded to said coupler, said teeth extending laterally and said coupler operable to form an annular space in soil around said bit with grooves formed in said soil by said teeth; and (e) grout in said annular space and said grooves.

2. The foundation piling of claim 1, wherein said lead section has a flight of helical threads on said first end.

3. (canceled)

4. The foundation piling of claim 1, wherein said bit is operable to slide onto said first end of said extension section,

5. (canceled)

6. (canceled)

7. The foundation piling of claim 1, wherein said second end of said extension section has a second pair of holes formed therein,

8. (canceled)

9. The foundation piling of claim 1, wherein said coupler has a leading edge when said bit is rotating, said leading edge operable to compress soil as said bit is being rotated.

10. The foundation piling of claim 1, further comprising a motor operable to rotate said extension section, said bit and said lead section rotating in response to rotation of said extension section.

11.-17. (canceled)

18. A foundation piling, comprising: a lead section having a first end and a second end opposing said first end, said first end being pointed and said second end having a pair of opposing holes formed therein; an extension section having a first end and a second end opposing said first end, said first end of said extension section operable to receive said second end of said lead section and having a first pair of opposing holes formed therein, wherein said first pair of opposing holes in said first end of said extension section are registrable with said pair of opposing holes of said second end of said lead section when said second end of said lead section is received in said first end of said extension section; fasteners extending through said first pair of opposing holes of said first end of said extension section and said pair of opposing holes of said second end of said lead section when said first pair of opposing holes of said first end of said extension section are in registration with said pair of opposing holes of said second end of said lead section; a bit carried by said first end of said extension section and prevented from moving from said first end of said extension section toward said second end of said extension section by said fasteners, said bit including a cylindrical pipe dimensioned to receive said first end of said extension section therein; a coupler welded to said cylindrical pipe wherein said coupler has a leading edge: at least one tooth carried by said bit, said at least one tooth extending laterally with respect to said bit and extending laterally with respect to said leading edge of said coupler, wherein said bit is operable to bore a hole having an annular region with lateral grooves formed therein, said leading edge of said coupler being operable to compress soil when said bit is penetrating said soil and rotating, and said at least one tooth is operable to carve said lateral grooves in the soil adjacent to the annular region formed by coupler of said bit; and grout in the annular region.

19. The foundation piling of claim 18, wherein said lead section has a flight of helical threads on said first end.

20. The foundation piling of claim 18, wherein said bit is operable to slide onto said first end of said extension section.

21. (canceled)

22. The foundation piling of claim 18, wherein said second end of said extension section has a second pair of holes formed therein.

23. (canceled)

24. (canceled)

25. The foundation piling of claim 18, further comprising a motor operable to rotate said extension section, wherein said bit and said lead section rotate in response to rotation of said extension section.

26. (canceled)

27. The foundation piling of claim 18, wherein said at least one tooth is at least two teeth.

28. The foundation piling of claim 18 wherein said coupler is made of steel.

29. The foundation piling of claim 18, wherein said coupler is made of angle steel.

30. The foundation piling of claim 18 wherein said at least one tooth is made of steel plate.

31. the foundation piling of claim 18, wherein said cylindrical pipe is steel pipe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Having thus described variations of the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0023] FIG. 1 is a perspective view of the bit according to an aspect of the disclosure;

[0024] FIG. 2 is a top view of the bit of FIG. 1;

[0025] FIG. 3 is a side view of the bit of FIG.;

[0026] FIG. 4 is an end view of the bit of FIG. 1;

[0027] FIG. 5 is a side, partially cross-sectional view of the apparatus for constructing a pile showing a lead section attached to three extension shafts, the first of which extension shafts having the bit of FIG. 1 installed on its first end, and which are being screwed into the soil using a motor on the end of a construction vehicle hydraulic arm to construct a foundation piling according to an aspect of the disclosure;

[0028] FIG. 6 is a side, partially cross-sectional view of a foundation piling being completed by the addition of grout in the annular region formed by the apparatus shown in FIG. 5, according to an aspect of the disclosure;

[0029] FIG. 7A is an exploded perspective showing an extension shaft, a bit, and a lead section and according to an aspect of the disclosure;

[0030] FIG. 7B is a side perspective view showing the bit installed on an extension section that is secured to a lead section;

[0031] FIG. 7C shows a side view of the apparatus of FIG. 7B rotated a quarter turn as indicated by the arrows; and

[0032] FIG. 8 is a perspective view of a tapered foundation piling made with the bit according to an aspect of the disclosure.

DETAILED DESCRIPTION

[0033] There is herein disclosed apparatus for constructing foundation pilings. Referring now to the figures, an apparatus 10 is best seen in FIG. 5, and may include a lead section 24, a bit 28, one or more extension sections 32, 32, 32, a motor 36 for rotating lead section 24, bit 28, and extension sections 32, 32, 32, and grout 40. Apparatus 10 may be held in position over the designated location for a foundation pile by a hydraulic arm 44 of a construction vehicle 48 such as a backhoe or perhaps a crane.

[0034] Referring specifically to FIGS. 1-4, there is illustrated bit 28 in perspective, and in a top view, side view and end view, respectively. Bit includes a cylindrical pipe 52 dimensioned to receive extension section 32. Attached to cylindrical pipe 52 are couplers 56. Couplers 56 serve two functions. They provide a surface on which to attach teeth 60 and they also provide a leading edge 64 that will press against the soil 68 of the wall 72 of the hole 76 (see FIGS. 5 and 6) to compress it, thereby leaving an annular region between extension section 32 and wall 72 for grout 40.

[0035] Teeth 60 carve a groove in wall 72 that may also be filled with grout 40 and thereby increase lateral strength of the piling to be constructed.

[0036] Bit 28 may be made of steel, and therefore couplers 56 may be welded to cylindrical pipe 52 and teeth 60 welded to couplers 56. An aspect of the disclosure is that cylindrical pipe 52, couplers 56, and teeth 60 may be made of basic steel shapes, namely, steel pipe, angle steel, and steel plate so that they can be made inexpensively and quickly.

[0037] Referring to FIGS. 7A-C, lead section 24 has a first end 80 and a second end 84. For convenience, the term first end will refer to the lowermost end or first end into the hole being bored; likewise, the term second end will refer to the upper most end or the second end into the hole being bored. First end 80 is preferably closed and may be pointed to facilitate boring. At least one flight 88 of helical screw threads will assist in helping to advance lead section 24 into the soil. Lead section has at least one and may have two sets of opposing holes 92, 96, in its second end 84.

[0038] As shown in detail and, before being secured to lead section 24 in FIG. 7A and after, in FIGS. 7B and C, extension sections 32 may also be cylindrical and have a first end 100 and a second end 104. First end 100 is expanded to have a larger diameter than second end 104. Extension sections have at least one first pair of holes 112, 116, at said first end 100 and at least a second pair of holes 120, 124, at said second end 104. Holes 112, 116, may be 13/16 at three inches on center cut in opposing sides of pipe

[0039] Bolts 128, 132 and nuts 136, 140, fasten second end 84 of lead section 24 to first end 100 of extension section 32. As shown in FIG. 7C, nuts 136, 140, like coupler 56, have a secondary function. They serve as stops to prevent bit 28 from moving upward when lead section is boring into the ground. As extension section 32 is screwed into the ground by lead section 24, soil 68 pushes bit 28 up until cylindrical pipe 52 butts up against nuts 136 carried by bolt 128 connecting extension section 32 to lead section 24. Bit 28 is secured in place by the upward pressure exerted by soil 68 surrounding bit 28. Use of nuts 136, 140, and the heads of bolts 128, 132, eliminates the need for any welding of bit 28 to extension section 32, which saves time in construction of the pilings and reduces overhead costs.

[0040] As the hole 76 is bored, it is filled with grout 40 in a liquid state, which, when cured, encases lead section 24, bit 28 and extension sections 32, 32, 32and, once grout 40 is solidified, creates a solid, steel-reinforced, concrete column around them. This solid grout column bears the load of the structure after a cap 144 is applied. Cap 144 is embedded in the footing that supports the foundation slab.

[0041] Prior to practicing the method, an analysis of the soil at the site for construction is performed. Quality of the soil will indicate the number of foundation pilings that will be used to support the load of the structure to be constructed. Load is determined by the type of soil present on the construction site, which is determined by soil analysis. The size of lead section 24 may then be determined based on the calculated load. The size of the pipe shaft of extension sections, typically 3 inches or 4 inches in diameter, depends upon the load to be borne by the foundation piling.

[0042] Grooves 148 created in the wall 72 increase surface area of the soil 68 that will be in contact with grout 40, which increases capacity, in comparison to a prior art piling of the same length having a smooth-sided grout column. Because grooves 148 increase the amount of soil 68 in contact with grout 40, foundation piles made with apparatus 10 have increased compressive and lateral capacity in comparison to prior art helical pier systems having the same dimensions where the grout columns are smooth-sided. Capacity further increases as number of grooves 148 per meter of depth increases. Frequency of grooves 148 is determined by the speed at which extension section 32 is turned and downward pressure exerted by hydraulic arm 44 on motor 36 to drive lead section 24 through soil 68. Quality of soil 68 will determine the range of speed and pressure that can be applied.

[0043] Grooves 148 in wall 72 increase surface area of hole 76 in contact with grout 40. Increasing the surface area of grout 40 to soil 68 increases the skin friction or shear stress along the finished piling. Skin friction or shear stress is the principal source of vertical support for friction piles, which are known support loads in proportion to the length of the shaft of the pile, as opposed to end-bearing piles that are driven through soil to rest on rock or a very firm soil layer.

[0044] Bits 28 of different sizes can be installed onto extension sections 32, 32, 32 to create a tapered grout column in which extension sections 32, 32, 32 of the column increase in diameter toward the surface of the ground. Increases in girth of the column is understood to increase capacity of the piling. Bits 28 having couplers 56 that are wider and welded to cylindrical pipe 52 can be applied to extension sections 32, 32, to increase the diameter of the cavity that will form the grout column.

[0045] A foundation piling during construction according to the method is shown in FIG. 6. As shown in FIG. 5, lead section 24 is secured to extension section 32 carrying bit 28. Additional extension sections as can be accommodated by apparatus 10 are secured together to be screwed into soil 68 by motor 36. As lead section 24 screws into soil 68, bit 28 is pushed onto first end 100 of extension section 32. Bit 28 may be temporarily attached near second end 84 of lead section 24, above flight 88 with tape for convenience, so that it is held above the first end 80 of lead section 24, if several are used on lead section 24. Bit 28 is pushed onto coupler 56 until cylindrical pipe 52 butts up against nuts 136.

[0046] As motor 36 continues driving lead section 24 further into the ground, hole 76 formed around outside of bit 28 is filled with grout 40 pumped from a supply through a hose 148 as hole 76 is created. Grout 40 is added as hole 76 is deepened by lead section 24 advancing downward through soil 68.

[0047] Tapered foundation pilings 152, as shown in FIG. 8 can also be made using the same size of extension section 32. Diameter of hole 76 is increased by applying bits having couplers 56, 56 that are incrementally wider to extension sections 32, 32. When wider, couplers 56, 56 increase the overall width of bit 28, meaning that hole 76 is widened when bit 28 turns in response to rotation of extension section 32. Tapered foundation pilings 152 can be made that incrementally taper up from 8 inches in diameter at the bottom of the grout column to 16 inches in diameter at the top. Grout would be added to hole 76 as suggested by showing hose 148 in dashed lines as hole 76 is created, but was not illustrated for clarity of the drawing.