Abstract:
A helical pier with a spiral tip is disclosed. The helical pier is comprised of an elongated hollow shaft, one or more helical plates attached to and extending outward from the shaft, and the spiral tip. The spiral tip acts as an attack bit that contacts and penetrates the ground and subsurface soil layers prior to other parts of the helical pier. The spiral tip provides initial breakup of the ground where the helical pier is being driven. The spiral tip is comprised of a longitudinal edge and a spiral rim between a penetrating lead end and a terminating spiral end on the longitudinal edge.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to a steel pier. The disclosure particularly relates to a steel pier having one or more helical plates and a spiral tip formed on the periphery of the steel pier. 
       BACKGROUND 
       [0002]    Helical piers are deep foundation elements used to support compression, tension and/or lateral loads from buildings and structures. Helical piers of hollow tubular sections may have varying lengths and diameters. The shaft of a pier transfers the supported load from the structure to deep competent soil via helical (or helix) bearing plates. Piers include helical plates welded to the shaft, where the number of helices, their diameter, position on the shaft, and their thickness affect the efficacy of receiving and transferring the structure&#39;s load based on surrounding ground conditions. 
         [0003]    Piers are rotated (or screwed) into the ground by the application of torque using a rotary drive head mounted to a machine or hand-held equipment. Machines applying the torque may vary; for example, machine may be a small walk-behind excavator, rubber-tired backhoe, or large track excavator. When advancing a pier into the ground, operators try to limit disturbance to the soil where the pier penetrates because soil disturbance may adversely affect the soil bearing capacity and the capacity of the pier when it is put in service. Therefore, the tip of a pier section may be designed to improve the process of breaking through the ground and subsequent subsurface soil layers to the depth necessary to provide the structure with adequate support and stability. 
         [0004]    The ability to advance a pier into soil is affected by many factors, some of which include the drive head capacity and the size and weight of the installation equipment. The soil or bedrock type, strength, and nature of deposition may also prove to hinder pier installation. Soil and rock mechanics will change depending on geography and soil characteristics, such as soil types and soil layers. For instance, in Nebraska, Iowa, Kansas, and Missouri, there are distributions of loess sediments. Loess is a clastic and mostly silt-sized sediment formed by the accumulation of wind-blown dust. Calcium carbonate lightly cements the composition of clay, sand and silt. The sediment is highly porous with vertical capillaries that permit fracturing. In contrast to loess, bentonite and montmorillonite clays in places like Denver, Colo. are absorbent clays that swell and shrink, respectively, from water absorption and evaporation of rainfall and melting of snowfall. These expansive clays, which can be found in Colorado, Wyoming, and South Dakota, can fluctuate in resistance to pier penetration when the clay is saturated with water compared to when it is fissured (or dried). Differences in soil types affect installation factors such as the torque needed to advance a helical pier or the ability to advance the pier at the proper penetration rate. 
         [0005]    Therefore, completing foundation repairs and new construction support solutions requires careful selection of helical piers (shaft size, helical plate configuration, specialty lead details, etc.) based on knowledge of the soil conditions of the project site. What is needed is a helical pier for drier, compact soils, thin layers of dense soils, and lightly to moderately-cemented soils with a lead tip that improves pier installation by maintaining consistent penetration rate and avoiding excess disturbance of the soil as the pier advances into and through the ground. 
       SUMMARY OF THE INVENTION 
       [0006]    The present disclosure provides a helical pier with a spiral tip. The helical pier is comprised of an elongated hollow shaft, one or more helical blades (or plates) attached to and extending outward from the shaft, and the spiral tip. The spiral tip acts as an attack bit that contacts and penetrates the ground and subsurface soil layers prior to other parts of the helical pier. The spiral tip provides initial breakup of the ground where the helical pier is being driven. Using a helical pier with a spiral tip more easily penetrates cemented soils and thin layers of dense soil, helps seat piers into weathered bedrock, hard clay and dense sand, and allows for a more consistent penetration rate. A helical pier with a spiral tip may be installed, for example, with a rotary drive head. 
         [0007]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The Detailed Description is described with reference to the accompanying figures. 
           [0009]      FIG. 1  is an angled profile view of a spiral tip on a helical pier held in a lateral position. 
           [0010]      FIG. 2  is a front profile view of a spiral tip on a helical pier held in a lateral position. 
           [0011]      FIG. 3  is a side profile view of a spiral tip on a helical pier held in a vertical position. 
           [0012]      FIG. 4  is a transparent profile view of a spiral tip and helical blade. 
           [0013]      FIG. 5  is a cross-sectional view of a helical pier with a spiral tip in the process of being driven into soil. 
           [0014]      FIG. 6  is a cross-sectional view of a helical pier with a spiral tip in its final resting place driven into soil. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Referring generally to  FIGS. 1 through 6  ( FIGS. 1-6 ), a helical pier with a spiral tip is illustrated and described herein. For purposes of this disclosure, the term “helical pier” is interchangeable with and may mean a pier, pile, anchor, helical pile, or helical anchor and applies in the field of helical foundation supports. 
         [0016]      FIGS. 1 through 3  ( FIGS. 1-3 ) show multiple perspective views of a helical pier  100  with a spiral tip  101 .  FIG. 4  ( FIG. 4 ) shows a transparent profile view of a spiral tip  101  and helical blade  201  that may comprise a helical pier  100 .  FIGS. 5 and 6  ( FIGS. 4 and 5 ) exemplify embodiments of the helical pier  100  with a spiral tip  101  connected to a one or more additional helical piers  501 , where the helical pier  100  includes a plurality of helical blades  201  between the spiral tip  101  and a trailing end  301 . 
         [0017]    As seen in  FIG. 1 , the helical pier  100  comprises an elongated hollow shaft  302  with a longitudinal axis  401 , a spiral tip  101 , a helical blade  201 , and a peripheral surface  303 . The longitudinal axis  401  is intangible and at the center of the elongated hollow shaft  302 , about which the helical pier  100  rotates when driven into the ground by a rotary steel pipe driver. The peripheral surface  303  is between the spiral tip  101  and the trailing end  301  of the helical pier  100 . The peripheral surface  303  spans the length of the helical pier  100 . 
         [0018]    The spiral tip  101  is formed by cutting out a spiral portion of the helical pier  100  at a penetrating end opposite the helical pier&#39;s  100  trailing end  301 . The spiral cutout is made starting along an edge of the penetrating end of the helical pier  100  and cutting in a spiral direction. The spiral cutout may be made using equipment such as a tube laser at a manufacturing facility; however, the spiral cutout may also be made as a field modification using portable equipment such as a band saw. 
         [0019]    The result of the spiral cutting process is a spiral tip  101  which includes a longitudinal edge  102  that is substantially parallel to the longitudinal axis  401  of the helical pier  100 . The longitudinal edge  102  has a penetrating lead end  104  and a spiral terminating end  105 . The spiral tip  101  also includes a spiral rim  103  defined by a spiral rim portion of the helical pier  100  between the penetrating lead end  104  and the spiral terminating end  105 . The spiral tip  101  may be a variety of sizes based on the size of the helical pier  100  (e.g., the diameter of the helical pier  100 ). The length of the longitudinal edge  102  may also vary based factors such as the desired pitch of the spiral rim  103  and the diameter of the helical pier  100 . The pitch of the spiral rim  103  is a rim pitch. The length of the longitudinal edge  102  may affect the rate with which the helical pier  100  penetrates a particular ground site. Measurements of the rim pitch correspond with measurements of the longitudinal edge  102 —an increase in the degree of the rim pitch corresponds to a longer longitudinal edge  102  measurement. 
         [0020]    In addition to the spiral tip  101 , the helical pier  100  may also have a helical blade  201 . The helical blade  201  attaches to the peripheral surface  303  of the helical pier  100 , preferably by welding. A helical blade  201  may have a single turn that traverses a spiral (or arc) path about the peripheral surface  303  of a helical pier  100  (i.e., welding the helical blade  201  along the peripheral surface  303  approximately three-hundred sixty degrees). Even with only one turn, the helical blade  201  may have a blade pitch that is substantially constant (i.e., does not vary significantly in slope from one end (or edge) of the helical blade  201  to the other end). The helical blade  201  has a diameter from the peripheral surface  303  to its outward edge, where the diameter is a defining size feature of the helical blade  201 . The thickness of the helical blade  201  is another defining size feature of the helical blade  201 , which may vary. The size features of a helical blade  201  affect the load capacity of the helical pier  100 , as well as the level of disturbance of soil during the application of torque advancing the helical pier  100  into soil. The blade pitch of the helical blade  201  helps advance the helical pier  100  into the soil. 
         [0021]    The blade pitch of the helical blade  201  may correspond with the rim pitch of the spiral tip  101 . For example, the blade pitch of the helical blade  201  may be three inches, and the rim pitch of the spiral tip  101  may also be three inches. In other helical piers  100 , though, the blade pitch of the helical blade  201  may be different from the rim pitch of the spiral tip  101 . For example, the blade pitch of the helical blade  201  may be four inches, and the rim pitch of the spiral tip  101  may be two inches. 
         [0022]    A helical blade  201  may also have a plurality of (or multiple) turns that follow a spiral path about the peripheral surface  303  of a helical pier  100 . A helical blade  201  with a plurality of turns may spiral greater than three-hundred sixty degrees (e.g., five-hundred forty degrees or seven-hundred twenty degrees). A helical blade  201  with multiple turns may have a substantially constant pitch (or slope), as the material comprising the helical blade  201  (e.g., steel) spirals about the peripheral surface  303  of the elongated hollow shaft  302 . 
         [0023]    In other embodiments of the helical pier  100 , it may have a plurality of helical blades  201 . That is, the helical pier  100  may have two or more helical blades  201  spaced along the elongated hollow shaft  302 , each helical blade  201  spiraling about the peripheral surface  303  for one or more turns. A plurality of helical blades  201  may have positions along the elongated hollow shaft  302  such that spacing between each consecutive pair of blades is approximately equal. Each helical blade  201  may have a substantially constant pitch (or slope) in embodiments of the helical pier  100  with a plurality of helical blades  201 . Furthermore, in embodiments, each helical blade  201  from the plurality of helical blades  201  may each have substantially equal blade pitches. 
         [0024]    A helical blade  201  includes a first radial edge  202  and a second radial edge  203 . The second radial edge  203  is distal to the first radial edge  202  due to the spiraling of the helical blade  201  about the peripheral surface  303  of the elongated hollow shaft  302 . As seen in  FIG. 4 , a helical blade  201  may be attached to the helical pier  100  such that the blade&#39;s first radial edge  202  and second radial edge  203  are aligned with each other along the peripheral surface  303  to the elongated hollow shaft  302 . The first radial edge  202  in  FIG. 4  demonstrates an ability to shape the edge to include a slanted face (or surface) corresponding to the rotational direction for driving the helical pier  100  into soil. Such a slant to the first radial edge  202  may improve advancement of the helical pier  100  into the soil compared to an edge with a flat vertical face. In contrast, the second radial edge  203  in  FIG. 4  is shaped to have a slanted face at a substantially parallel angle to the first radial edge  202 . Such a second radial edge  203  may improve load bearing resistance compared to an edge with a flat vertical face. 
         [0025]    Further, in one embodiment of the present disclosure where there is only one helical blade  201  attached to the helical pier  100 , the first radial edge  202  of the helical blade  201  may be proximal to the spiral terminating end  105  of the spiral tip  101 . In another embodiment of the present disclosure where the helical pier  100  is comprised of a plurality of helical blades  201 , one helical blade of the plurality may have a first radial edge  202  proximal to the spiral terminating end  105  of the spiral tip  101 . 
         [0026]    As seen in  FIGS. 5 and 6 , by similar means known in the art for other helical pier types, the helical pier  100  with a spiral tip  101  may be fastened to another helical pier  501 . The helical pier  100  may be the lead pier in a series of helical piers  501  fastened together to reach the desired depth for load transference from the building or other structure in need of foundation support to more solid soil deeper in the ground.  FIG. 5  demonstrates a second helical pier  501  being attached to the helical pier  100  that has been driven into the soil.  FIG. 6  illustrates a final resting condition for a series of helical piers  501  fastened together with the lead helical pier being a helical pier  100  with a spiral tip  101 , as described in this disclosure. 
         [0027]    Although the subject matter has been described in language specific to structural features, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features described above. Rather, the specific features described above are disclosed as example forms of implementing the claims.