1. Field of the Invention
The present invention relates to wire facing units for reinforced earthen retaining walls wherein the face of the retaining wall is formed by a vertically extending section of the wire facing unit and which includes an integral horizontally extending floor that extends rearwardly for securing a polymer geogrid thereto. More particularly, the present invention relates to a combined, unitary connector strut which interconnects and supports the face and floor of the wire facing unit, while at the same time securing a geogrid to the floor, as well as the assembly of retaining walls with the wire facing unit and connector strut, and methods of constructing a retaining wall with such elements.
2. Description of the Related Art
The use of welded wire facing units in the construction of retaining walls is well known as is the use of polymer geogrids to reinforce such earthen formations. See, for example, U.S. Pat. Nos. 4,856,939 and 6,595,726, each of which discloses the construction of a geogrid-reinforced earthen retaining wall incorporating welded wire facing units. Polymer geogrids, particularly uniaxially stretched integral polymer geogrids of the type preferred for use in the construction of such retaining walls, may be made by the process disclosed in U.S. Pat. No. 4,374,798.
The above-referenced '726 patent discloses a wire facing unit having a face section and a floor section, with the floor section including protuberances defining aligned openings adjacent a rear edge of the floor section. The protuberances provide an effective arrangement for receiving the polymer geogrid by the placement of selected geogrid apertures over the protuberances and then inserting a relatively lengthy connecting rod through the aligned openings of the protuberances to retain the geogrid to the floor section. The connecting rod overlies the geogrid and is captured by the protuberances to retain the geogrid from disengagement with the wire facing unit under high stress conditions. In addition, a separate strut element is provided to interconnect the top of the face section with the rearward portion of the floor section, essentially defining a hypotenuse of a triangle, to support the face section with respect to the floor section and to provide strength to the overall wire facing unit. Thus, two separate and distinct elements were required to support the facing unit, as well as to connect or secure the geogrid to the floor of the facing unit.
The retaining wall system of the '726 patent has been commercialized. Although cost effective and successful, multiple steps are required to install the system. One of the first steps is to connect the geogrid to the wire facing unit through the insertion of the connector rod. A separate distinct step requires installation of the separate support struts. In the commercial system, support struts are typically required to be spaced apart no more than 16 inches to maintain proper face alignment in accordance with design guidelines of the American Association of State Highway and Transportation Officials (“AASHTO”). Specifically, such guidelines require that the face structure bulge not exceed two inches.
In addition to requiring separate and distinct connecting rods and strengthening struts, each of which perform different functions, the insertion of the elongated connecting rods is difficult to achieve where the connecting rod has to extend through several aligned openings, particularly where separate and distinct wire facing units lie in a horizontal side-by-side relationship. The connecting rod has to be lengthy, approximately the width of the facing unit because insertion is from an end region and needs to extend to or near the opposite end region. Further, for facing units intermediate the two end units, it is often required that the facing units be tilted for insertion of the connecting rod and frequently requires the connecting rod to be relatively flexible for ease of insertion. This is time consuming and labor intensive.
An initial object of the present invention is to provide a retaining wall system comprising, in combination, an assembly of elements, including a wire facing unit and a geogrid, with a unique interconnection between these elements which overcomes the foregoing and other disadvantages of prior art systems.
A further object of this invention is to provide a combined connector strut formed from a unitary or one-piece rigid rod. Specifically, it is an object of the present invention to provide a connector strut that includes an elongated support strut portion that strengthens and supports the wire facing unit and an orthogonally directed connector rod, or link, portion having a length substantially less than the width of the wire facing unit to connect and secure the geogrid to the floor of the wire facing unit quickly and easily.
Yet another object of this invention is the utilization of the connector strut with a known wire facing unit wherein the wire elements forming the rear end portions of the floor section are bent into generally inverted U-shaped protuberances which define aligned openings extending generally transversely of the floor section of the wire facing unit. The wire elements forming the protuberances are preferably spaced apart by a distance equal to, or a multiple of, the spacing between the apertures defined in the forward end portion of the geogrid so that the geogrid can be laid over the rear end of the floor section of the wire facing unit with the upstanding floor section protuberances extending through the geogrid apertures. (In the event the spacing between the geogrid apertures does not align with the spacing of the protuberances, the transverse bar of the geogrid can be cut or slit to enable the geogrid to fit over the protuberances.) The connector rod portion of the unitary connector strut can then be inserted through the aligned openings formed by the protuberances to secure the geogrid directly to the rear end of the floor section of the wire facing unit and the elongated strut portion of the unitary connector strut can then be secured to a top edge of the face section.
A still further object of this invention is to provide an assembly of elements, and a method of using the elements to easily and inexpensively form a reinforced retaining wall section, requiring the use of no extraneous materials or tools, and providing a secure engagement between the wire facing unit forming the face section of the wall and the geogrid reinforcing the fill material behind the wall.
Other and further objects of this invention will be readily understood by those with ordinary skill in the art with particular reference to the following detailed description of the preferred embodiments in combination with the accompanying drawings.
Like reference characters refer to like parts throughout the several views of the drawings.
In describing a preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
A retaining wall constructed using the system of the instant invention is designated generally by the reference numeral 10 in
Each of the layers 20, 20′ of the retaining wall 10 are formed from an assembly of elements including a wire facing unit 40, 40′ one or more sections of geogrid 50, 50′, a connecting strut 60, 60′, and a body of fill material 80, 80′, such as aggregate, including soil, or the like.
The wire facing unit 40, 40′ commonly formed of metal with a face section 42, 42′, and a floor section 44, 44′, formed by continuous, longitudinally extending wire elements 46, 46′, bent generally at an angle, preferably a right angle and interconnected by a plurality of spaced, transversely extending, welded cross-wires 48, 48′. Specifically, the face section 42, 42′ includes a plurality of parallel wire elements 46, 46′ extending from a free top edge 43, 43′ to a bottom edge 45, 45′ wherein the parallel wire elements 46, 46′ are interconnected by at least one transverse cross-wire element 48b, 48b′ at the top edge 43, 43′. The floor section 44, 44′ extends angularly from the face section 42, 42′ from the face section bottom edge 45,45′. The floor section 44, 44′ has a free rear edge 49, 49′ and is similarly formed from plural parallel wire elements 46, 46′ extending from the bottom edge 45, 45′, to the rear edge 49, 49′. The parallel wire elements 46, 46′ of the floor section 44, 44′ are interconnected by at least one transverse cross-wire element 48a, 48a′ the rear edge 49, 49′. Protuberances 55, 55′ are formed adjacent the rear edge 49, 49′ and define aligned openings 47, 47′. The wire facing unit 40, 40′ is depicted in
The geogrid section 50 can have any width and any length, and can be formed using any well-known prior art technology, including weaving, knitting, or other techniques for securing strands or straps to each other to form a grid-like construction. Preferably, however, the geogrid sections are formed as integral, uniaxially-stretched, polymer geogrids in accordance with the teachings of the '798 patent referenced above. Regardless of the method of forming the geogrid, it will include a plurality of spaced, generally parallel, strand elements such as shown at 52, 52′, interconnected by generally transversely extending cross-bars 54, 54′ or other strands which together define a multiplicity of through-apertures 56. Moreover, according to a preferred embodiment of this invention, the width of a geogrid section 50 is equal to, or an even fraction of, the width of a wire facing unit 40 so as to facilitate construction of a retaining wall according to this invention. However, geogrid sections smaller or larger than the width of a facing unit or a non-even fraction of the width of a facing unit can be used without departing from the instant inventive concepts.
At the rear end portions of the floor section 44 of the wire facing unit 40 of this invention, the longitudinally extending wire elements 46 are bent to form upstanding, generally U-shaped, protuberances 55 extending from the upper face of the floor section 44 to define generally aligned openings 47 extending generally transversely of the floor section 44 of the wire facing unit 40. The portions of the wire elements 46 forming the protuberances may be tilted forwardly to form an inclined shoulder or pocket 51 to more securely engage a geogrid section 50 as described below.
In constructing a geogrid-reinforced retaining wall section according to this invention, a wire facing unit 40 is positioned as seen, for example, in
If desired, an erosion blanket 30 of conventional construction, such as a geotextile, may be placed inside the wire facing unit 40, and aggregate 80, such as soil or the like, is then filled behind the rear face of the face section 42, on top of the upper face of the floor section 44 of the wire facing unit 40, and over the geogrid section 50.
A further tier or layer of geogrid-reinforced retaining wall, such as 20′ shown in
Obviously, if desired, the superior sections can be positioned directly above the inferior sections to form a retaining wall with a continuous, generally vertical, face (not shown), rather than a stepped-back face (as shown), but the stepped-back arrangement enhances the stability of the face of the retaining wall and enables the incorporation of plantings such as illustrated at 90 in front of upper face sections for erosion control and improved aesthetics.
The connector strut 60 of the present invention is depicted in
As shown in
The distance between the free first end 64 of the connector strut rod 62 to the bend 68 is substantially equal to the distance between the transverse cross-wire element 48b at the top edge 43 of the face section 42 and the protuberances 55 on the floor section 44. See, for example, the fully assembled structure of
The interconnection between the geogrid 50, the wire facing unit 40, and the connector strut 60, and the method for interconnecting the three items is depicted in
After positioning of the uniaxial geogrid apertures over the corresponding protuberances 55 of the floor section (keeping in mind that a one-to-one correspondence is not required—as shown in
After all of the connector rod portions 69 of the connector struts 60 are threaded through the aligned openings 47 of the floor section protuberances 55 and the connector struts lie upon the geogrid 50, the connector struts 60 are then rotated upward by the installer so as to hook the curved first end 64 to the transverse cross-wire element 48b at the top edge 43 of the face section 42. The rotation is shown schematically in
The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. As noted, the invention may be configured in a variety of shapes and sizes and is not limited by the dimensions of the preferred embodiment. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the preferred embodiments or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
This application is entitled to and hereby claims the priority of U.S. provisional application Ser. No. 61/272,669 filed Oct. 19, 2009.
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Number | Date | Country | |
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Number | Date | Country | |
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61272669 | Oct 2009 | US |