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 soil reinforcing elements. In most applications, the soil reinforcing elements 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 wall, typically made of concrete or steel facing panels, may be constructed a short distance from the standing earthen wall, or constructed simultaneously as the earthen wall rises upward. The vertical wall not only serves as decorative architecture, but also prevents erosion of the earthen wall. The soil reinforcing mats extending from the compacted backfill may be attached directly to the back face of the vertical wall in a variety of configurations. To facilitate this connection, the vertical wall will frequently include a plurality of facing anchors either cast into or attached somehow to the back face of the wall at predetermined and/or spaced-apart locations. Each facing anchor is typically positioned so as to correspond with and couple directly to the end of a soil reinforcing mat. Via this attachment, outward movement and shifting of the vertical wall is significantly reduced.
Although there are several methods of attaching soil reinforcing elements to facing structures, it nonetheless remains desirable to find improved facing anchors and soil reinforcing mat connectors offering less expensive alternatives and greater resistance to shear forces inherent in such structures.
Embodiments of the disclosure may provide a system for securing a facing to an earthen formation. The system may include a soil reinforcing element having a pair of longitudinal wires welded to a plurality of spaced transverse wires, wherein the pair of longitudinal wires have lead ends that converge toward one another. The system may further include a connection stud having a first end coupled to the lead ends of the longitudinal wires and a second end defining one or more holes centrally-disposed therethrough, and a facing anchor having first and second connection points extending from a back face of the facing and vertically-offset from each other a distance X, each connection point defining a horizontally-disposed perforation. The system may also include a coupling device configured to be coupled simultaneously to the horizontally-disposed perforation of each connection point and the hole of the connection stud to thereby secure the connection stud to the facing anchor. When connected, the soil reinforcing element is capable of swiveling in a horizontal plane and shifting vertically over the distance X.
Another exemplary embodiment of the disclosure may provide a method of securing a facing to a soil reinforcing element. The method may include welding a pair of converging lead ends of the soil reinforcing element to a first end of a connection stud, and inserting a second end of the connection stud into a gap formed between first and second connection points of a facing anchor, the second end and first and second connection points each defining a horizontally-disposed perforation therein, wherein the first and second connection points extend from a back face of the facing and are vertically-offset a distance X. The method may further include securing the connection stud against separation from the facing anchor by inserting a coupling device simultaneously into the horizontally-disposed perforations of each of the second end and first and second connection points. Once connected, the soil reinforcing element is capable of swiveling in a horizontal plane and shifting vertically over the distance X.
Another exemplary embodiment of the disclosure may provide a connection stud for securing a soil reinforcing element to a facing. The connection stud may include a stem having a first end and a second end, the second end of the stem being coupled to a pair of converging longitudinal wires from the soil reinforcing element. The connection stud may also include a tab coupled to the first end of the stem and defining at least one hole within the tab, wherein the tab is configured to be secured via the at least one hole to a facing anchor extending from a back face of the facing. Once connected, the soil reinforcing element may be capable of swiveling about an axis defined through the at least one hole in a horizontal plane and shifting vertically over a distance X.
It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure, however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Further, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Furthermore, as it is used in the claims or specification, the term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein.
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, disclosed is a low-cost, one-piece MSE connector, and variations of the same, that allows soil reinforcing mats to swivel in order to avoid vertically-disposed obstructions, such as drainage pipes, catch basins, bridge piles, or bridge piers, which may be encountered in the backfill field. The MSE connector may also allow soil reinforcing mats to shift vertically in reaction to MSE settling or thermal expansion/contraction of an MSE structure. The ability of the soil reinforcing element to shift and swivel provides a distinct advantage in that the structural integrity of the MSE system is not jeopardized over time, but that it may move in response to natural occurrences.
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The earthen formation or backfill 104 may encompass an MSE structure including a plurality of soil reinforcing elements 110 that extend horizontally into the backfill 104 to add tensile capacity thereto. In an exemplary embodiment, the soil reinforcing elements 110 may serve as tensile resisting elements positioned in the backfill 104 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 soil reinforcement elements 110, but it is not uncommon to employ “geogrids” made of plastic or other materials to accomplish the same end.
In the illustrated exemplary embodiment, the soil reinforcing element 110 may include a welded wire grid having a pair of longitudinal wires 112 that are substantially parallel to each other. The longitudinal wires 112 may be joined to a plurality of transverse wires 114 in a generally perpendicular fashion by welds at their intersections, thus forming a welded wire gridworks. In exemplary embodiments, the spacing between each longitudinal wire 112 may be about 2 in., while spacing between each transverse wire 114 may be about 6 in. As can be appreciated, however, the spacing and configuration may vary depending on the mixture of tensile force requirements that the reinforcing element 110 must resist.
In one or more embodiments, lead ends 116 of the longitudinal wires 112 may generally converge toward one another and be welded or otherwise attached to a connection stud 118. The connection stud 118 may include a first end or a stem 120 coupled or otherwise attached to a second end or a tab 122. As will be described below, several variations of the connection stud 118 may be implemented, without departing from the disclosure. In at least one embodiment, the stem 120 may include a cylindrical body having an axial length L. As illustrated, the lead ends 116 may be coupled or otherwise attached to the stem 120 along at least a portion of the axial length L. In one embodiment, the tab 122 may be a substantially planar plate and define at least one centrally-located perforation or hole 124.
In at least one embodiment, the facing anchor 108 may include a pair of horizontally-disposed connection points or plates 126a, 126b cast into and extending from the back face 106 of the panel 102. As can be appreciated, other embodiments include attaching the facing anchor directly to the back face 106, without departing from the disclosure. Furthermore, as can be appreciated, other embodiments of the disclosure contemplate a facing anchor 108 having a single horizontal plate 126 (not shown), where the tab 122 is coupled only to the single plate 126 via appropriate coupling devices.
Each plate 126a,b may include at least one perforation 128 adapted to align with a corresponding perforation 128 on the opposing plate 126a,b. As illustrated in
In this arrangement, the soil reinforcing element 110 (as coupled to the connection stud 118) may be allowed to swivel or rotate about axis Y in a horizontal plane Z (
Moreover, the gap 132 defined between two vertically-offset plates 126a,b may also prove significantly advantageous. For example, the gap 132 may compensate or allow for the settling of the MSE structure as the soil reinforcing element 110 settles in the backfill 104. During settling, the tab 122 may be able to shift or slide vertically about the nut and bolt assembly 130 the distance X, thereby compensating for a potential vertical drop of the soil reinforcing element 110 and preventing any buckling of the concrete facing 102. As will be appreciated by those skilled in the art, varying designs of anchors 108 may be used that increase or decrease the distance X to compensate for potential settling or other MSE mechanical phenomena.
Furthermore, it is not uncommon for concrete facings 102 to shift in reaction to MSE settling or thermal expansion/contraction. In instances where such movement occurs, the soil reinforcing elements 110 of the disclosure are capable of correspondingly swiveling about axis Y and shifting the vertical distance X to prevent misalignment, buckling, or damage to the concrete facing 102.
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As illustrated, the stem 402 may include a plurality of indentations or grooves 412 defined, cast, or otherwise machined along its axial length L. In at least one embodiment, the grooves 412 can include standard thread markings machined along the axial length L. In other embodiments, the stem 402 may include axial channels (not shown) having grooves 412 similar to the axial channels 204, 308 shown and described in
In other embodiments, the facing anchor 108 may include a single horizontal plate 126 extending from the back face 106, and the tab 406 may be appropriately coupled thereto by positioning the upper and lower prongs 406a,b above and below the single plate 126. In such an embodiment, the distance X may be defined between the two prongs 406a,b, thereby continuing to allow the soil reinforcing element 110 to vertically translate the distance X in response to MSE settling or expansion/contraction. As can be appreciated, alterations to the design of the connection stud 402 may be undertaken to increase the distance X defined between upper and lower prongs 406a,b, and thereby provide the soil reinforcing element 110 more vertical distance to translate.
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As with prior embodiments, a coupling device, such as a nut and bolt assembly 130 or the like, may be inserted through the connection points or loops 602a and 602b of each loop anchor 600a,b and simultaneously through the hole 124 defined in the tab 122. Once secured to the loop anchors 600a,b, the connection stud 118 may be able to swivel or rotate about axis Y in a horizontal plane (not shown), and move vertically up and down the nut and bolt assembly 130 for the predetermined distance X.
While the connection stud 118 generally described with reference to
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.
The present application claims priority to U.S. Utility patent application Ser. No. 12/353,615, entitled “Retaining Wall Soil Reinforcing Connector and Method,” which was filed on Jan. 14, 2009, the contents of which are incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | 12353615 | Jan 2009 | US |
Child | 12756898 | US |