Patent Publication Number: US-10309073-B1

Title: System and method for enhancing structural performance of deep foundation pile members

Description:
RELATED APPLICATION 
     The application claims priority to provisional patent application U.S. Ser. No. 62/419,560 filed on Nov. 9, 2016, the entire contents of which is herein incorporated by reference. 
    
    
     BACKGROUND 
     The embodiments herein relate generally to deep foundation pile members. More specifically, the invention relates to cast-in-drilled hole reinforced concrete piles. 
     Cast-in-drilled hole reinforced concrete piles with enlarged bases are commonly used foundations to support houses, buildings, piers, and other structures above the ground. These reinforced concrete piles are formed by digging a hole within the ground to create an upper shaft cavity connected to a larger lower bell-shaped base cavity. These types of piles, also known as Bell-Bottomed Pier Deep Foundations are formed by inserting a cage into the hole comprising a plurality of rebars connected together and disposing concrete into the hole to secure the cage in place. 
     Current Bell-Bottomed Pier Deep Foundation Piles are structurally inefficient, which results in the need for more pile constructions, concrete, reinforcement members and ultimately labor. This greatly increases the overall construction and/or maintenance costs of the piles. Further, the structural performance of these piles is deficient because the reinforcement members including the rebars are not properly oriented throughout the bottom bell-shaped cavity. As a result, this problematic design results in a greater incidence of shear cone stresses throughout the bottom bell-shaped cavity, which causes premature failure of the pile. 
     As such, there is a need in the industry for a system and method for enhancing the structural performance of cast-in-drilled hole reinforced concrete piles formed from an upper shaft cavity connected to a lower bell-shaped cavity within the ground. More specifically, there is a need for the concrete pile to have rebars better distributed throughout the upper shaft cavity and lower bell-shaped cavity to enhance the load-bearing capacity of the pile and reduce failure rates. 
     SUMMARY 
     A deep foundation reinforced concrete pile with enhanced structural performance for use in a hole in a ground surface is provided. The hole comprises an upper shaft cavity connected to a lower generally bell-shaped cavity. The deep foundation concrete pile comprises a cage assembly disposed within the hole in the ground surface and comprises a plurality of rebars coupled together by a plurality of fixtures and extending through the upper shaft cavity and the lower bell-shaped cavity, each fixture comprising a generally hexagonal sheet comprising a plurality of fingers extending from an outer edge of the sheet, each finger in the plurality of fingers connected to the hexagonal sheet at a corner junction comprising a concave edge formed by the finger and outer edge of the sheet, the plurality of fixtures oriented so the plurality of fingers of each fixture are aligned with the plurality of fingers in an adjacent fixture in the plurality of fixtures, each rebar in the plurality of rebars configured to be secured within the concave edges of the corner junctions of the plurality of fixtures, and concrete disposed within the hole in the ground to secure the cage assembly therein, thereby enhancing the structural performance of the reinforced concrete pile by minimizing shear stress failure and enhancing load-bearing capacity of the pile. 
     In certain embodiments, each fixture in the plurality of fixtures comprises a central opening, the central opening comprising an edge with a plurality of inner hooks, each rebar in the plurality of rebars configured to be secured within the inner hooks of the plurality of fixtures. 
     In certain embodiments of the invention, a method to enhance structural performance of a deep foundation reinforced concrete pile in a hole in a ground surface is provided. The method comprises providing a cage assembly, disposing the cage assembly into the hole so the upper handle sections of the rebars remain above the ground surface, the neck sections of the rebars extend within the upper shaft cavity of the hole, and the lower bent sections of the rebars extend within the lower bell-shaped cavity, rotating the upper handle sections of the rebars to permit the lower bent sections of the rebars to extend outward into space within the bell-shaped cavity of the hole, and disposing concrete into the upper shaft cavity and lower bell-shaped cavity of the hole. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The detailed description of some embodiments of the invention will be made below with reference to the accompanying figures, wherein the figures disclose one or more embodiments of the present invention. 
         FIG. 1  depicts a section view of a reinforced concrete deep foundation pile in the prior art; 
         FIG. 2  depicts a perspective view of certain embodiments of the deep foundation pile illustrating a cage fixture; 
         FIG. 3  depicts a perspective view of certain embodiments of the deep foundation pile; 
         FIG. 4  depicts a section view of certain embodiments of the deep foundation pile taken along line  4 - 4  in  FIG. 3 ; 
         FIG. 5  depicts a section view of certain embodiments of the deep foundation pile; 
         FIG. 6  depicts a section view of certain embodiments of the deep foundation pile; 
         FIG. 7  depicts a top view of certain embodiments of the deep foundation pile illustrating a first exemplary rebar; 
         FIG. 8  depicts a side view of certain embodiments of the deep foundation pile illustrating the first exemplary rebar; 
         FIG. 9  depicts a perspective view of certain embodiments of the deep foundation pile illustrating a cage assembly; 
         FIG. 10  depicts a bottom perspective view of certain embodiments of the deep foundation pile illustrating the cage assembly; 
         FIG. 11  depicts a bottom view of certain embodiments of the deep foundation pile illustrating the cage assembly; 
         FIG. 12  depicts an exploded view of certain embodiments of the deep foundation pile; 
         FIG. 13  depicts a perspective view of certain embodiments of the deep foundation pile shown in use; 
         FIG. 14  depicts a perspective view of certain embodiments of the deep foundation pile shown in use illustrating the rotation of the upper handle sections of the rebars; 
         FIG. 15  depicts a bottom perspective view of certain embodiments of the deep foundation pile illustrating the corresponding rotation of the lower bent sections of the rebars; 
         FIG. 16  depicts a perspective view of certain embodiments of the deep foundation pile shown in use; 
         FIG. 17  depicts a section view of certain embodiments of the deep foundation pile shown in use; 
         FIG. 18  depicts a section view of certain embodiments of the deep foundation pile taken along line  18 - 18  in  FIG. 17 ; 
         FIG. 19  depicts a perspective view of certain embodiments of the deep foundation pile in an alternative configuration; 
         FIG. 20  depicts a perspective view of certain embodiments of the deep foundation pile illustrating the alternative configuration in use; 
         FIG. 21  depicts a section view of certain embodiments of the deep foundation pile illustrating the alternative configuration in use; 
         FIG. 22  depicts a section view of certain embodiments of the deep foundation pile taken along line  22 - 22  in  FIG. 21 ; 
         FIG. 23  depicts a perspective view of certain embodiments of the deep foundation pile illustrating the cage fixture in an alternative configuration; 
         FIG. 24  depicts a section view of certain embodiments of the deep foundation pile shown in use in an alternative configuration; 
         FIG. 25  depicts a section view of certain embodiments of the deep foundation pile taken along line  25 - 25  in  FIG. 24 ; 
         FIG. 26  depicts a top view of certain embodiments of the deep foundation pile illustrating a second exemplary rebar; 
         FIG. 27  depicts a side view of certain embodiments of the deep foundation pile illustrating the second exemplary rebar; 
         FIG. 28  depicts a perspective view of certain embodiments of the deep foundation pile; 
         FIG. 29  depicts a perspective view of certain embodiments of the deep foundation pile; and 
         FIG. 30  depicts a section view of certain embodiments of the deep foundation pile. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
     As depicted in  FIG. 1 , a cast-in-drilled hole reinforced concrete pile in the prior art is shown, which is configured to support a structure (not shown) above the ground such as a pier, house or other building. The prior art pile is formed within ground  42  of the earth in a hole comprising upper shaft cavity  44  connected to a lower bell-shaped cavity  48 . In one exemplary configuration, upper shaft cavity  44  comprises a diameter of approximately 12″ and lower bell-shaped cavity  48  comprises a diameter of approximately 36″. However, the dimensions of the cavity may vary. The pile is constructed by disposing prior art cage assembly  62  into the cavity in ground  42 . 
     Cage assembly  62  comprises a plurality of non-formed rebars  30  coupled together by horizontal cages  38 . Concrete  52  is disposed into upper shaft cavity  44  and lower bell-shaped cavity  48  via a pump to secure cage assembly  62  within the cavity. Structural performance of the prior art reinforced concrete pile is deficient due to potential misalignments of the non-formed rebars  30  within upper shaft cavity  44  and the failure of non-formed rebars  30  to extend outward into space within lower bell-shaped cavity  48 . This design can be problematic due to the increased potential for shear cone stress failures  54  in the pile when in use. 
       FIGS. 1-13 and 17  depict certain embodiments of a reinforced concrete pile with enhanced structural performance. The reinforced concrete pile is formed with cage assembly  40 , which comprises a plurality of first exemplary rebars  26  coupled together by horizontal cages  38  and cage fixtures  10  as depicted in  FIG. 9 . It shall be appreciated that at least two cage fixtures  10  and any number of horizontal cages  38  may be used. Depending on the application, the spacing between horizontal cages  38  and spacing between cage fixtures  10  may vary. It shall be appreciated that embodiments of the invention are advantageous because first exemplary rebars  26  comprising a generally higher quantity of smaller rebars are used than is typically applied in the prior art piles. 
     As depicted in  FIGS. 2-4 , each cage fixture  10  comprises a generally hexagonal-shaped sheet with a central opening, outer fingers  14  and inner hooks  18 . The hexagonal-shaped sheet may be made from any materials including, but not limited to, steels such as carbon steel or stainless steel, fiberglass, plastic, and the like. In a preferred embodiment, each outer finger  14  is connected to the hexagonal-shaped sheet at a corner junction and comprises foldable tab  12 . The corner junction creates an outer hook along a concave edge formed by outer finger  14  and the outer edge of the hexagonal-shaped sheet. Inner hooks  18  are formed along the inner edge along the central opening in the hexagonal-shaped sheet. In one embodiment, each cage fixture  10  comprises visual alignment holes  20 . 
     Cage fixtures  10  are configured to secure the plurality of first exemplary rebars  26  together. In one embodiment, first exemplary rebar  26  is made from #4 rebar  22  as depicted in the top view in  FIG. 7  and side view in  FIG. 8 . Each #4 rebar  22  comprises formed upper handle section  32  continuously connected to formed neck section  34  continuously connected to formed lower bent section  36 . As depicted in  FIGS. 3-4 , formed neck sections  34  of #4 rebars  22  are secured within the outer hooks formed by the concave edges extending from outer fingers  14  to the hexagonal-shaped sheets. In alternative embodiments, it shall be appreciated that each cage fixture  10  may comprise different outer shapes to accommodate a different number of rebars. 
     In a preferred embodiment, a pair of retaining protrusions  16  extend from the concave edge of each outer finger  14  of cage fixture  10  as depicted in  FIG. 5 . Retaining protrusions  16  contact the rebar to help secure the member within outer finger  14  of caged fixture  10 .  FIG. 6  depicts first exemplary rebar  26  using #3 rebar  24  in an alternative placement within outer finger  14  of caged fixture  10 . It shall be appreciated that first exemplary rebars  26  can be made from various materials including, but not limited to, steel, reinforced plastic or fiberglass, and may have variable specifications. 
     As depicted in  FIGS. 9-11 , the assembled cage assembly  40  comprises a plurality of first exemplary rebars  26  coupled together by cage fixtures  10  and horizontal cages  38 . Each horizontal cage  38  comprises a ring tied to first exemplary rebars  26  by a plurality of wires. As depicted in  FIGS. 12-13 , cage assembly  40  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48  within ground  42 . One or more support blocks  46  may be used to stabilize cage assembly  40  during the assembly. In one embodiment, support block  46  is a wooden 2″×4″ or 2″×6″ block disposed on the ground and in contact with a portion of cage assembly  40  such as an upper horizontal cage  38  to support formed upper handle sections  32  of first exemplary rebars  26  above ground  42 . In this configuration, formed lower bent sections  36  of first exemplary rebars  26  are clumped together and bent inward within lower bell-shaped cavity  48  in ground  42 . 
     As depicted in  FIGS. 14-16 , the one or more support blocks  46  can be manually turned to its side face to lift cage assembly  40  further up above ground  42 . This lifts the ends of formed lower bent sections  36  of first exemplary rebars  26  off the bottom of lower bell-shaped cavity  48 , thereby permitting the rotation of the rebars with greater ease. Formed upper handle sections  32  of first exemplary rebars  26  are rotated as shown by the arrows in the figures to permit a corresponding rotation of the formed lower bent sections  36 . The rotation of the rebars are performed until lower bent sections  36  of first exemplary rebars  26  extend outward away from each other and into space within lower bell-shaped cavity  48  that was previously unreinforced. Cage fixtures  10  are beneficial because they effectively secure first exemplary rebars  26  in an aligned configuration and permit the rotation of the rebars during the installation of cage assembly  40  in ground  42 . 
     As depicted in  FIGS. 17-18 , concrete  52  is disposed within both upper shaft cavity  44  and lower bell-shaped cavity  48  to secure cage assembly  40  in place within ground  42 . In this configuration, the reinforced concrete pile is configured to support a structure disposed thereon above the ground. The structural performance of the reinforced concrete pile is enhanced because formed neck sections  34  of first exemplary rebars  26  are properly aligned throughout upper shaft cavity  44  and formed lower bent sections  36  extend outward and away from each other through the space within lower bell-shaped cavity  48 . As a result, the incidence of sheer cone stress failures throughout the pile when in use is greatly reduced. 
     In an alternative embodiment, first exemplary rebars  26  are coupled within inner hooks  18  of cage assembly  40  as depicted in  FIGS. 19-22 . In this alternative embodiment, cage assembly  40  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48 , maneuvered and assembled in the same manner as previously described. First exemplary rebars  26  may be secured to inner hooks  18  or outer fingers  14  of cage fixtures  10  to satisfy the particular strength requirements and/or comply with any applicable codes. 
       FIGS. 23-25  depict an alternative embodiment of the reinforced concrete pile. In this alternative configuration, foldable tabs  12  of each cage fixture  10  are folded up as depicted in  FIG. 23 . Cage assembly  40  is assembled together using first exemplary rebars  26 , cage fixtures  10  and horizontal cages  38  as previously described. Tube  56  is disposed within upper shaft cavity  44  in ground  42  to create air gap  58  as depicted in  FIGS. 24-25 . In one embodiment, tube  56  comprises an approximate diameter of 10″ and is made from any materials such as cardboard. Cage assembly  40  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48 , maneuvered and assembled in the same manner as previously described. In this configuration, foldable tabs  12  may contact tube  56 . Concrete  52  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48  to complete the assembly of the reinforced concrete pile. The primary purpose of tube  56  is to separate concrete  52  from the earth in ground  42 . 
     Foldable tabs  12  of cage fixtures  10  reduce the diameter of cage assembly  40 . This reduces the concrete volume when cage assembly  40  is used with tube  56 . Tube  56  creates a smoother shaft surface that will have a lower surface friction coefficient. This smooth surface of the pile will better resist soil adhesion that occurs within clayey soil due to soil moisture changes. A soil depth zone called a ‘moisture effected zone’ is typically estimated to extend nominally 6 to 8 feet below the surface. Expanding soil in this zone can grab and lift a typical rough walled augured pile causing damage and/or foundation distress. By improving the isolation of the reinforced concrete pile from the soil, the pile can be designed to be shorter than a non-isolated pile. In addition, a smaller diameter reinforced concrete pile will provide equal or better structural performance due to a more accurate location of reinforcement rebar closer to the pile shaft wall. 
       FIGS. 26-30  depict an alternative embodiment of the reinforced concrete pile with cage assembly  40  formed by second exemplary rebars  28 . Second exemplary rebars  28  are coupled together by horizontal cages  38  and cage fixtures  10  as previously discussed.  FIG. 26  depicts a top view of second exemplary rebar  28  and  FIG. 27  depicts a side view of second exemplary rebar  28 . Each second exemplary rebar  28  comprises formed upper handle section  32  continuously connected to formed neck section  34  continuously connected to formed lower bent section  36 , which comprises a curvature. As depicted in  FIGS. 28-30 , cage assembly  40  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48 , maneuvered and assembled in the same manner as previously described. Concrete  52  is disposed within upper shaft cavity  44  and lower bell-shaped cavity  48  to complete the assembly of the reinforced concrete pile. In this alternative embodiment, the curvature of formed lower bent sections  36  extend outward and away from each other through the space within lower bell-shaped cavity  48 . 
     In certain embodiments of the invention, a method to enhance structural performance of a cast-in-drilled hole reinforced concrete pile is provided. The method comprises one or more of the following steps. 
     First, any cage assembly  40  described in embodiments of the invention is constructed and provided. This is assembled above ground  42  and typically comprises connecting a plurality of first exemplary rebars  26  or second exemplary rebars  28  together using cage fixtures  10  and horizontal cages  38 . An individual may use visual alignment holes  20  of cage fixtures  10  to ensure a proper alignment of the fixtures when securing them to first or second exemplary rebars  26 ,  28 . Once assembled, formed bent sections  36  of the rebars are pointed inward and in a closed position as depicted in  FIGS. 9, 19 and 28 . 
     Cage assembly  40  is disposed into upper shaft cavity  44  and lower bell-shaped cavity  48  in ground  42  so that formed upper handle sections  32  of the rebars remain above ground  42 , formed neck sections  34  of the rebars extend within upper shaft cavity  44  and formed lower bent sections  36  extend within lower bell-shaped cavity  48 . This may be performed manually by one or more individuals or by a machine such as a crane. One or more support blocks  46  may be used to stabilize cage assembly  40  during the installation as shown in  FIGS. 13-14 . In one embodiment, the one or more support blocks  46  are turned on their side faces to lift cage assembly  40  further up above ground  42 . This lifts the ends of formed lower bent sections  36  of the rebars off the bottom of lower bell-shaped cavity  48  in ground  42 . 
     Formed upper handle sections  32  of the rebars are rotated either manually by hand or via a tool such as a wrench to permit a corresponding rotation of the formed lower bent sections  36 . The rotation of the rebars are performed until lower bent sections  36  of first exemplary rebars  26  or second exemplary rebars  28  extend outward away from each other and into space within lower bell-shaped cavity  48  that was previously unreinforced. Concrete  52  is disposed into upper shaft cavity  44  and lower bell-shaped cavity  48  in ground  42  either manually or via a tool such as a pump. This completes the assembly of the reinforced concrete pile. 
     In an alternative embodiment, foldable tabs  12  of cage fixtures  10  are folded up during the assembly of cage assembly  40  as depicted in  FIGS. 23-25 . In this embodiment, tube  56  is disposed within upper shaft cavity  44  in ground  42  to create air gap  58  as depicted in  FIGS. 24-25 . In this configuration, foldable tabs  12  of cage fixtures  10  may contact tube  56 . Air gap  58  can be left open or be back-filled with concrete, cement-sand, other sand mixture, expanding urethane foam, or other filler. 
     It shall be appreciated that the components of the reinforced concrete pile described in several embodiments herein may comprise any alternative known materials in the field and be of any color, size and/or dimensions. It shall be appreciated that the components of the reinforced concrete pile described herein may be manufactured and assembled using any known techniques in the field. 
     Persons of ordinary skill in the art may appreciate that numerous design configurations may be possible to enjoy the functional benefits of the inventive systems. Thus, given the wide variety of configurations and arrangements of embodiments of the present invention, the scope of the invention is reflected by the breadth of the claims below rather than narrowed by the embodiments described above.