Abstract:
A connection for securing the longitudinal wires of a soil reinforcing mat to a face element for an earthen formation is provided by converging the lead ends of the wires toward one another and forming aligned coils distally on the lead ends. A pin extending through the coils secures the soil-reinforcing mat to the face element for pivotal movement relative thereto in a horizontal plane. A variety of means are provided to secure the coils against unwinding in response to tension force applied to the wires.

Description:
RELATED APPLICATION  
       [0001]    This application is based upon and claims the benefit of Provisional Application 60/240,198, filed Oct. 13, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a new and improved way of attaching a welded wire soil-reinforcing grid to a facing system for use in mechanically stabilized earth (MSE) retaining structures. The invention is an improvement over the prior art in that it places even stress on the tension elements, defined herein as the longitudinal wires of the soil-reinforcing grid. Further, the present invention allows a welded wire grid to translate in a horizontal plane with respect to the facing panel.  
           [0003]    One form of prior art relies on attaching welded wire reinforcing grid by forming a loop or special crimp in individual longitudinal wires of the grid. The loops are formed by bending the wire 180° and welding the bent end to the longitudinal wire. This forms an integrated loop. This apparatus appears in U.S. Pat. No. 4,725,170-Davis. The loop of the welded wire grid is then placed through a coiled anchor that is cast into the back of a concrete face panel. The loop of the soil reinforcing grid and anchor are in a vertical plane which is perpendicular to the back face of the panel.  
           [0004]    In another prior art MSE system the longitudinal wire is bent 90° and attached with a plate and bolt to the back of the facing unit. In another system the longitudinal wire is crimped and joined to an anchor with a connection pin. These can be seen in U.S. Pat. No. 5,749,680-Hilfiker and U.S. Pat. No. 4,324,508-Hilfiker, respectively. The arrangement of patent U.S. Pat. No. 5,749,680 allows the reinforcing grids to translate in a horizontal plane with respect to the facing panel.  
           [0005]    Other prior art places the transverse wire of the welded wire grid work behind a loop that is formed in a panel anchor. The welded wire grid is attached to the panel anchor with a connection pin. This appears in U.S. Pat. No. 5,259,704-Orgorchock.  
           [0006]    Still other prior art bends a single longitudinal wire 180° to form a paired longitudinal wire hairpin configuration. Welded to the paired longitudinal wires are transverse wires, which form a welded wire grid work. This combination forms an integral loop at the lead end of the soil-reinforcing element. The anchoring element protruding from the back of a panel is a formed loop. The soil-reinforcing element and loop are joined with the aid of a snap together mechanism. This can be seen in the prior art Alviterra connection shown in FIG. 1.  
           [0007]    One block system utilizes a reinforcing element having parallel longitudinal wires with loops formed in each end. Each longitudinal wire is placed in counter bores formed in the top surface of a block. Rods are inserted through the counter bores and loops to secure the reinforcing element in the block. This arrangement can be found in U.S. Pat. No. 5,487,623-Anderson.  
           [0008]    A second block system utilizes a flat polymeric soil reinforcing mat that is placed between blocks. The soil reinforcing mat is sandwiched between the blocks. The blocks are secured together by a pin that anchors the grid. This can be seen in U.S. Pat. No. 4,914,876-Forsberg.  
           [0009]    U.S. Pat. No. 6,050,748 -Anderson, discloses a variety of loop connectors on the ends of the longitudinal wires of soil reinforcing mats to secure these mats to face elements. Of particular interest are the connections seen in FIGS.  47  to  52  of this patent which include overlapping loops which are engaged between or over connecting elements embedded in the face panels.  
         SUMMARY OF THE INVENTION  
         [0010]    A principal object of the present invention is to provide an apparatus and method for attaching the face of an earthen retaining structure to a soil-reinforcing element through means of loops formed by parallel longitudinal wires of the element. The loops are overlapped on top of one another. The loops can be formed in numerous fashions. The use of separate wires makes manufacturing of the loops easier. The loops are attached to the face so that the soil-reinforcing element is free to rotate about the axis of the loops. This allows the soil-reinforcing element to be skewed at an angle to the back face of the structure. An advantage of the overlapping loops is that when a force is applied to the longitudinal wires each loop tightens upon itself. This tightening increases the connection capacity. In addition, the connection is mechanical and does not rely on the weld shear of a transverse wire. Further, the soil-reinforcing element can be rotated to pass obstructions. Additionally, since two longitudinal wires are utilized in lieu of one there is twice the strength available.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a plan view showing the prior art Alviterra mat;  
         [0012]    [0012]FIG. 2 is a top plan view of a first embodiment of the connection of the present invention;  
         [0013]    [0013]FIG. 3 is a side elevational view of the first embodiment connection;  
         [0014]    [0014]FIG. 4 is an end elevational view of the first embodiment connection, shown connected to an anchor element;  
         [0015]    [0015]FIG. 5 is a side elevational view of the first embodiment connection, shown connected to a generally U-shaped anchor element embedded in a concrete face panel;  
         [0016]    [0016]FIG. 6 is an elevational cross-sectional view of first modification of the first embodiment connection wherein a flanged sleeve is inserted through the coils of the connection;  
         [0017]    [0017]FIG. 7 is a top plan of a second modification of the first embodiment connection, wherein the looped wires of the connection are bent 180° about themselves and welded together at their lead ends;  
         [0018]    [0018]FIG. 8 is a side elevational view of the connection of FIG. 7;  
         [0019]    [0019]FIG. 9 is a top plan view of a third modification of the first embodiment connection wherein the looped wires of the connection are bent 180° about themselves and twisted together;  
         [0020]    [0020]FIG. 10 is a top plan view of a second embodiment of the connection of the present invention;  
         [0021]    [0021]FIG. 11 is a top plan view of a third embodiment of the connection of the present invention;  
         [0022]    [0022]FIG. 12 is an end elevational view of the third embodiment connection;  
         [0023]    [0023]FIG. 13 is a side elevational view of the third embodiment connection;  
         [0024]    [0024]FIG. 14 is a first modified version of the third embodiment connection wherein the loops are kinked;  
         [0025]    [0025]FIG. 15 is a side elevational view of the first embodiment connection, shown connected to concrete block face elements;  
         [0026]    [0026]FIG. 16 is a side elevational view of the first embodiment connection, shown attached to a cast concrete face element having a bifurcated shelf for receiving the connection;  
         [0027]    [0027]FIG. 17 is a side elevational view of the first embodiment connection, shown attached to a cast concrete face element having an open shelf for receiving the connection;  
         [0028]    [0028]FIG. 18 is a side elevational view of the first embodiment connection, shown attached to a welded wire face element;  
         [0029]    [0029]FIG. 19 is a side elevational view of the first embodiment connection, shown secured between two concrete facing elements;  
         [0030]    [0030]FIG. 20 is a top plan view of the FIG. 19 arrangement, showing the connection to the lower face panel shown in FIG. 19, with the upper panel removed;  
         [0031]    [0031]FIG. 21 is a top plan view showing a modified version of the arrangement wherein the connection is held between segmental concrete panels, and the panels are made up of block-like elements;  
         [0032]    FIGS.  22  is a side elevational view of the arrangement shown in FIG. 21;  
         [0033]    [0033]FIG. 23 is a top plan view of an arrangement wherein the connection is between block elements and the pin securing the connection to the elements does not tie successive rows of block elements together; and  
         [0034]    FIGS.  24  to  26  are top plan views illustrating how the connection of the present invention allows the soil reinforcing grids attached to various forms of face elements to translate in a horizontal plane relative to the face elements.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     First Embodiment  
       [0035]    The first embodiment of the present invention consists of a welded wire grid  1  containing paired longitudinal wires  2 A,  2 B that are substantially parallel to one another. Cross members  3  are joined to the longitudinal wires in a perpendicular fashion by welds at their intersections  4 . The lead ends of the longitudinal wires are manufactured into a coil-loop  5  by wrapping the longitudinal wire around a pin. This forms a through-hole  6  in the end of the wire. The paired longitudinal wires are deflected inward toward one another so the through-holes overlap. The welded wire grid is attached to the back of a concrete element C by placing the coiled-loop between the legs of anchor elements  8  (see FIG. 5). The anchor elements  8  are C-shaped and each consist of a top leg  9  and a bottom leg  10 , each leg having a hole  11  extending therethrough of approximately the same diameter as the opening in the coil-loop. A rebar  7  extends within the concrete element C and through the bight portion of the anchor element  8 . Through the intersecting holes in the anchor and the coil-loop, a bolt or a pin  12  is placed. This ties the grid to the concrete panel  13  (see FIG. 5).  
         [0036]    To prevent the longitudinal wires from separating, until such time that a pin is passed through the anchor and the coil, the coils can be welded together or a hollow tube  14  can be placed through the coil-loop opening and the ends  15  flared outward as shown in the modification of FIG. 6. This tube will keep the holes from each coiled longitudinal  2 A,  2 B wire in line. The coiled assembly is then fastened to the anchor.  
         [0037]    The modification of the first embodiment connection shown in FIGS. 7 and 8 embodies a welded wire grid  1  having paired longitudinal wires  2 A,  2 B that are substantially parallel to one another and cross members  3  welded to the longitudinal wires at the intersections  4 . The lead ends of the longitudinal wires are laid over one another, with their ends bent 180° upon themselves, as may best be seen from FIG. 7. The loops are resistance welded to one another by “W” at their lead ends and where the distal portions of the loops cross (see FIG. 7).  
         [0038]    The third modified version of the first embodiment shown in FIG. 9 is similar to the second modification of FIGS. 7 and 8, except that in the FIG. 9 modification no welds are provided between the loops and the distal portions of the loops are twisted about themselves at “T.” This twisted connection prevents the loops from straightening and releasing under the application of tension forces to the wires  2 A and  2 B.  
       Second Embodiment  
       [0039]    The second embodiment of the present invention is shown in FIG. 10 and comprises welded wire grid  16  having paired longitudinal wires  2 A,  2 B that are substantially parallel to one another. Cross members  3  are joined to the longitudinal wires in a perpendicular fashion by a welds at their intersections  4 . The lead longitudinal wires are manufactured into a loop by bending the longitudinal wire 180° around a pin and welding the ends  17  of the wires to the longitudinal wires. This forms a loop  18  in the end of each longitudinal wire. The looped longitudinal wires are deflected inward toward one another so the through-holes  19  formed therein intersect. The wires are connected with a weld  20 , or a flared tube as previously described. The welded wire grid is then attached to the back of a concrete element by placing the loops between the legs of an anchor element. The anchor element corresponds to previously described element  8  and comprises a top leg and a bottom leg, each leg having a through-hole of approximately the same diameter as the opening in the coil loop. Through the intersecting holes in the anchor and the loops, a bolt or a pin is placed, similarly to what is seen in FIG. 5. This ties the grid to the concrete panel.  
       Third Embodiment  
       [0040]    A third embodiment of the present invention, as shown in FIGS.  11  to  13 , comprises a welded wire grid  1  having paired longitudinal wires  2 A,  2 B that are substantially parallel to one another. Cross members  3  are joined to the longitudinal wires in perpendicular fashion by welds at their intersections  4 . The lead longitudinal wires are deflected toward one another. The ends of the longitudinal wires are bent around one another in an over-lapping fashion and welded together, forming a closed loop  7 .  
         [0041]    The wires are placed in anchor as previously described (see FIG. 4). In order to make movement of the closed loop more restrictive, it can be formed with a kink, as shown in the modified version of the third embodiment shown in the modification of FIG. 14.  
       Use of the Connection  
       [0042]    Each of the embodiments can be attached to concrete panels as shown in FIGS. 16, 17,  19  and  20 , blocks as shown in FIG. 15, or a welded wire-facing element as shown in FIG. 18. Attachment can be made with an anchor  8  that is attached to the facing and captures the loops between the protruding top and bottom portions  9 ,  10 . In the block arrangement of FIG. 15, the element  8  is connected to the blocks B with a bolt or pin  22  that is “L” shaped.  
         [0043]    The panel arrangements can be made of cast concrete that is manufactured into a face panel D (FIG. 16) to provide bifurcated shelf having a slot  22  providing an opening that the loops are placed through, or as a simple shelf  24  (FIG. 17) upon which the loops rest. The soil-reinforcing elements are joined to the panels P with a pin  25 .  
         [0044]    The wire face arrangement (FIG. 18) employs a C-shaped anchor element  8 A similar to the element  8  previously described. The C-shaped element is placed to the front of the facing element, designated  26 , and captures two transverse wires of the facing element. The soil-reinforcing element is attached by placing a bolt or pin  12  through the opening in the anchor and the coil loops.  
         [0045]    The coil loops can also be attached by capturing the loops between two concrete facing elements  29 A, segmental concrete panels or segmental concrete blocks  29 B, as shown in FIGS.  19  to  22 . In these arrangements, the loops are placed in a void that is cast into the top surface of the concrete element. A segmental concrete element is placed on the soil-reinforcing element. Cast into the void is a hole  30  that will allow a pin  32  to be set in the panel and passed through the soil-reinforcing loop opening securing it from removal. The pin can pass into the segmental element above.  
         [0046]    [0046]FIG. 23 shows a connection to a block arrangement in which the pin  34  for connecting the loop of the invention does not tie into the block  29 C row above, but is between successive paired blocks of above. The block  29 C is shaped in such a manner that the pin does not tie the second row of blocks together. It would be possible to pass the pin into the third row of blocks. This would tie every other row of blocks together.  
         [0047]    FIGS.  24 - 26  illustrates how the connection of the present invention allows a welded wire soil reinforcing grid to translate in a horizontal plane with respect to the facing member to which it is attached.  
         [0048]    While specific embodiments of the invention have been illustrated and described, it should be understood that the invention is not intended to be limited to these embodiments, but rather as defined by the claims.