Abstract:
A connection apparatus for securing a facing to a soil reinforcing element wherein the soil reinforcing element has a pair of adjacent longitudinal wires with horizontally extended converging portions, a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards and terminating at a head, a facing anchor having a pair of vertically disposed loops adjacently extending from the facing and having an opening for receiving a vertical portion of the stud, and a device configured to secure the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions.

Description:
BACKGROUND OF THE DISCLOSURE 
     Retaining wall structures that use horizontally positioned soil inclusions to reinforce an earth mass in combination with a facing element are referred to as Mechanically Stabilized Earth (MSE) structures. MSE structures can be used for various applications including retaining walls, bridge abutments, dams, seawalls, and dikes. 
     The basic MSE technology is a repetitive process where layers of backfill and horizontally placed soil reinforcing elements are positioned one atop the other until a desired height of the earthen structure is achieved. Typically, grid-like steel mats or welded wire mesh are used as earthen reinforcement elements. In most applications, the reinforcing mats consist of parallel transversely extending wires welded to parallel longitudinally extending wires, thus forming a grid-like mat or structure. Backfill material and the soil reinforcing mats are combined and compacted in series to form a solid earthen structure, taking the form of a standing earthen wall. 
     In some instances, a substantially vertical concrete wall may then be constructed a short distance from the standing earthen wall. The concrete wall not only serves as decorative architecture, but also prevents erosion at the face of the earthen wall. The soil reinforcing mats extending from the compacted backfill may then be attached directly to the back face of the vertical concrete wall. To facilitate the connection to the earthen formation, the concrete wall will frequently include a plurality of “facing anchors” either cast into or attached somehow to the back face of the concrete at predetermined and spaced-apart locations. Each facing anchor is typically positioned so as to correspond with and couple directly to an end of a soil reinforcing mat. 
     Via this attachment, outward movement and shifting of the concrete wall is significantly reduced. However, in cases were substantial shifting of the concrete facing occurs, facing anchors may be subject to shear stresses that result in anchor failure. Although there are several methods of attaching the soil reinforcing elements to the facing anchors, it remains desirable to find improved apparatus and methods offering less expensive alternatives and greater resistance to shear forces inherent in such structures. 
     SUMMARY OF THE DISCLOSURE 
     Embodiments of the disclosure may provide a connection apparatus for securing a facing to a soil reinforcing element. The connection apparatus may include a soil reinforcing element having a pair of adjacent longitudinal wires with horizontally extended converging portions, a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards and terminating at a head, a facing anchor having a pair of vertically disposed loops adjacently extending from the facing and having an opening for receiving a vertical portion of the stud, and a device configured to secure the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions. 
     Another exemplary embodiment of the present disclosure may provide a method of securing a facing to a soil reinforcing element. The method may include providing a soil reinforcing member having a pair of adjacent longitudinal wires having horizontally extended converging portions, providing a stud having a first end attached to the horizontally extended converging portions, and a second end bent upwards forming a vertical portion, wherein the vertical portion terminates at a head, inserting the vertical portion of the stud into an opening defined by a pair of vertically disposed loops adjacently extending from the facing and configured to receive the vertical portion of the stud, and securing the vertical portion of the stud against separation from the opening between the vertically disposed loops, wherein the stud and the attached soil reinforcing member are capable of swiveling in the horizontal and vertical directions. 
     Another exemplary embodiment of the present disclosure may provide a facing anchor for securing a soil reinforcing element to a facing. The facing anchor may include an unbroken length of continuous wire originating with a pair of lateral extensions and forming at least one pair of vertically disposed U-shaped segments, each having a first end and a second end, wherein the first end includes the U-shaped segments and the second end forming a horizontally disposed loop. 
     Another exemplary embodiment of the present disclosure may provide a connection apparatus to secure a facing to an earth structure. The connection apparatus may include a stud having a first end attached to a soil reinforcing element, and a second end bent upwards and terminating at a head, a pair of U-shaped wires defining a pair of corresponding apertures and extending from the facing and configured to receive the second end of the stud therebetween, whereby the head rests on the U-shaped wires, and a rod extensible through the pair of apertures and configured to secure the second end of the stud against separation from the U-shaped wires, wherein the stud and the attached soil reinforcing element are capable of swiveling in the horizontal and vertical directions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a top view of a system according to one or more aspects of the present disclosure. 
         FIG. 1B  is a side view of the system shown in  FIG. 1A . 
         FIG. 2  is side view of a connection stud according to one or more aspects of the present disclosure. 
         FIG. 3A  is a side view of an exemplary facing anchor configuration according to one or more aspects of the present disclosure. 
         FIG. 3B  is a perspective view of an exemplary facing anchor according to one or more aspects of the present disclosure. 
         FIG. 3C  is a top view of an exemplary facing anchor according to one or more aspects of the present disclosure. 
         FIG. 4A  is an exploded perspective view of a system according to one or more aspects of the present disclosure. 
         FIG. 4B  is a perspective view of a system according to one or more aspects of the present disclosure. 
         FIG. 4C  is a side view of an exemplary system according to one or more aspects of the present disclosure. 
         FIG. 5A  is a top view of a series of a system according to one or more aspects of the present disclosure. 
         FIG. 5B  is a side view of a series of a system according to one or more aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It is understood that the following disclosure provides several different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     The present disclosure may be embodied as an improved apparatus and method of connecting an earthen formation to a concrete facing of a mechanically stabilized earth (MSE) structure. In particular, one improvement of the present disclosure is a low-cost one-piece MSE connector that allows soil reinforcing mats to shift and swivel in reaction to the settling and thermal expansion/contraction of a MSE structure. Another improvement of the present disclosure is that the connector does not require its lead end to be threadably engageable with the connector. A further improvement includes a soil reinforcing element that is easier to fabricate and ship and thus has less chances for damage during shipping. Besides these improvements resulting in the advantages described below, other advantages of the improved connector and facing anchor combination include its ease of manufacture and installation. 
     Referring to  FIGS. 1A and 1B , illustrated is a system  100  according to one or more aspects of the present disclosure. In an exemplary embodiment, the system  100  may be used to secure a concrete facing  102  to an earthen formation  104 . The facing  102  may include an individual precast concrete panel or, alternatively, a plurality of interlocking precast concrete modules or wall members that are assembled into interlocking relationship. In another embodiment, the precast concrete panels may be replaced with a uniform, unbroken expanse of concrete or the like which may be poured on site. The facing  102  may generally define an exposed face  106  and a back face  108 ; the exposed face  106  typically comprising a decorative architecture facing and the back face  108  located adjacent to the earthen formation  104 . Cast into the facing  102 , or attached thereto, and protruding generally from the back face  108 , is at least one facing anchor  110 . 
     The earthen formation  104  may encompass an MSE structure including a plurality of soil reinforcing elements  112  that extend horizontally into the earthen formation  104  to add tensile capacity thereto. In an exemplary embodiment, the soil reinforcing elements  112  may include tensile resisting elements positioned in the soil in a substantially horizontal alignment at spaced-apart relationships to one another against the compacted soil. Depending on the application, grid-like steel mats or welded wire mesh may be used as reinforcement elements, but it is not uncommon to employ “geogrids” made of plastic or other materials. 
     In an exemplary application, as illustrated in  FIGS. 1A and 1B , a reinforcing element  112  may include a welded wire grid having a pair of longitudinal wires  114  that are substantially parallel to each other. Transverse wires  116  are joined to the longitudinal wires  114  in a generally perpendicular fashion by welds at their intersections, thus forming a welded wire gridworks. However, in alternative exemplary embodiments any angle will suffice, thus, the transverse wires  116  need not be perpendicular to the longitudinal wires as long as the welded wire grid nonetheless serves its tensile resisting purpose. In an exemplary embodiment, spacing between each longitudinal wire  114  may be about 4 in., while spacing between each transverse wire  116  may be about 6 in. As can be appreciated, however, the spacing and configuration may vary depending on the mixture of force requirements that the reinforcing element  112  must resist. The lead ends  118  of the longitudinal wires  114  generally converge toward one another and are welded to a connection stud  120 . 
     Referring to the illustrated exemplary embodiment in  FIG. 2 , the connection stud  120  may include a cylindrical body  200  bent at the distal end to an angle that may be about 90° relative to the body  200  thus forming a vertical portion  202 . In alternative exemplary embodiments, the angle may be less or even more than 90° and still remain within the workable scope of the disclosure. The vertical portion  202  terminates at a head  204  that is considerably larger than the diameter or cross section of the vertical portion  202 . The tail end  206  of the body  200  may include indentations or thread markings capable of providing stronger resistance welding to the leading ends  118  of the longitudinal wires  114 . 
     In an exemplary embodiment, the connection stud  120  may include a bolt with a hexagonal or square head, but may also include any material or configuration that encompasses substantially the same design intent. For example, in an alternative embodiment, the connection stud  120  may include a bent segment of bar stock or rebar including a thick washer welded to the top that acts as the head. 
     Referring to  FIGS. 3A and 3C , illustrated are side and top views, respectively, of an exemplary facing anchor  110  according to one embodiment of the present disclosure. As illustrated, the facing anchor  110  may include a pair of exposed vertically disposed loops  302  extending substantially perpendicularly from the back face  108  of the concrete facing  102 . In alternative embodiments, the facing anchor  110  may extend from the concrete facing  108  at various angles to fit any particular application and remain within the scope of the disclosure without departing from the spirit of the disclosure. The loops  302  may be fabricated from a pair of wire segments bent to form a 180° arcuate turn, thus forming a pair of U-shaped segments. The loops  302  may be welded to each other via at least one horizontal wire  304  which forms part of the anchor  110  that is embedded in the concrete panel  102 . 
     In one embodiment, as illustrated in  FIG. 3A , multiple horizontal wires  304  may be employed to render further stability and rigidity to the loops  302 . Wires  304  may be welded to the top and bottom horizontally extending ends of the anchors  110 . In alternative embodiments to fit various applications, the wires  304  may be attached at any suitable surface of the horizontally extending ends of the anchors  110 . Furthermore, as illustrated in  FIG. 5A , a pair of panel anchors  110  may be strategically coupled together by welding at least one connecting horizontal wire  304  to each anchor  110  in series. Moreover, a pair of anchors  110  may also be coupled via multiple horizontal wires  304 . As such, stabilized and rigid panel anchors  110  may be strategically placed in the concrete facing  102  at predetermined spaced-apart locations to match up directly with corresponding reinforcing elements  112 . As can be appreciated, any number of panel anchors  110  may be strategically coupled together by welding any number of horizontal wires  304  thereon. 
     In an alternative embodiment, as illustrated in  FIG. 3B , the facing anchor  110  may consist of an unbroken length of continuous wire originating with a pair of lateral extensions  312 . Similar to the embodiment in  FIG. 3A , the facing anchor  110  may include a pair of exposed vertically disposed loops  302 , formed by making a pair of 180° arcuate turns, thus forming a pair of U-shaped segments. However, the exemplary facing anchor  110  may also include a horizontally disposed loop  314  formed by making a single 180° arcuate turn to form a singular U-shaped segment. While the vertically disposed loops  302  may be configured to extend substantially perpendicularly from the back face  108  of the concrete facing  102 , the lateral extensions  312  and horizontally disposed loop  314  may be embedded within the facing  102  to provide stability and rigidity to the connection system  100 . 
     Also contemplated in the present disclosure, but not herein illustrated, is a continuous-wire facing anchor  110 , similar to the embodiment shown in  FIG. 3B , but having more than one pair of U-shaped segments  302  configured to extend substantially perpendicularly from the back face  108  of the concrete facing  102 . Thus, an exemplary continuous wire anchor  110  may include a series of U-shaped segment pairs  302  and terminating in a pair of lateral extensions  312  configured to be embedded within the facing  102  to provide stability and rigidity to the connection system  100 . As can be appreciated, the series of U-shaped segment pairs  302  may be spaced apart at predetermined distances, or randomly spaced to accommodate any number or design of soil reinforcing elements  112 . 
     Referring now to  FIG. 3C , which illustrates a top-view of the exemplary system  100 , a reinforcing grid  306  including a plurality of transverse members  308  and horizontal members  310  may also be cast into the concrete facing  102 . In operation, the reinforcing grid  306  may serve to reinforce the concrete facing  102  by providing added tensile strength. Moreover, the grid  306  may be cast into the facing  102  in front of the horizontal wires  304  of the panel anchor  110  so as to provide additional lateral strength for the facing anchors  110  by adding supplementary resistance to being pulled out of the concrete. 
     Referring to  FIGS. 4A and 4B , the soil reinforcing elements  112  are connected to the panel anchors  110  by inserting the vertical portion  202  of the connection stud  120  between the pair of vertically disposed loops  302  of the panel anchor  110 . Since the head  204  of the connection stud  120  is enlarged, the connection stud  120  and reinforcing element  112  combination may rest on the top portion of the loops  302 . Alternatively, as illustrated in  FIG. 4C , the soil reinforcing element  112  may be placed on the backfill  104  in a manner so that the head  204  of the connection stud  120  extends above the top portion of the loops  302  a distance Y, instead of resting directly on the loops  302 . Distance Y may be configured to provide a distance wherein the soil reinforcing element  112  may settle as the backfill  104  is compressed over time, thus avoiding potential stress on the connection. 
     The connection is made secure by extending a rod, such as a threaded bolt  402 , through the dual apertures now defined between the loops  302 , as shown in  FIG. 4B . In one embodiment, a nut and washer assembly  404  may be attached to the threaded end of the bolt  402  to prevent its removal. In an alternative embodiment, the threaded bolt  402  may be replaced with any type of connecting pin having the effect of keeping the soil reinforcing element from being removed from the anchor  110 . For example, a segment of wire, metal round stock, or rebar may be effectively utilized by passing said segment through the apertures defined by the vertical loops  302  and manually bending the respective ends of the segment so as to prevent its removal. In alternative embodiments, a pre-fabricated connector pin including prongs on each end may be provided that can be inserted into the apertures defined by the vertical loops  302  and serve to prohibit separation of the anchor  110  from the reinforcing element  112 . 
     The connection stud  120  allows for movement in certain paths of both the horizontal and vertical planes thus compensating for a wide range of shifting that typically occurs in an MSE structure. For example, it is not uncommon for concrete facings  102  to shift and swivel in reaction to MSE settling or thermal expansion and contraction. Embodiments of the present disclosure may allow shifting and swiveling in the directions and paths indicated by arrows  406  &amp;  408  in  FIG. 4A . Therefore, in instances where movement occurs, the soil reinforcements  112  are capable of shifting and swiveling correspondingly thereby preventing damage or misalignment to the concrete facing  102 . Moreover, because the connection stud  120  may swivel, during system  100  construction the soil reinforcing element  112  need not be situated perpendicular to the back face  108  of the facing panel  102 . Instead, the soil reinforcing element  112  may be attached at any angle relative to the back face  108 . In practice, this may prove advantageous since it allows the system  100  to be employed in areas where a vertical obstruction, such as a drainage pipe, catch basin, bridge pile, or bridge pier may be required. 
     Referring to  FIGS. 5A and 5B , illustrated are top and side views, respectively, of an exemplary embodiment of the system  100  of the present disclosure. As can be seen, the system  100  may be employed in series, both vertically and horizontally. 
     The foregoing disclosure and description of the disclosure is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the disclosure. While the preceding description shows and describes one or more embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure. For example, various steps of the described methods may be executed repetitively, combined, further divided, replaced with alternate steps, or removed entirely. In addition, different shapes and sizes of elements may be combined in different configurations to achieve the desired earth retaining structures. Therefore, the claims should be interpreted in a broad manner, consistent with the present disclosure.