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 may be used for various applications including retaining walls, bridge abutments, dams, seawalls, and dikes.
The basic MSE implementation 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, the soil reinforcing elements may be attached or otherwise coupled to a substantially vertical wall either forming part of the MSE structure or offset a short distance therefrom. The vertical wall is typically made either of concrete or a steel wire facing. The soil reinforcing elements extending from the compacted backfill may be attached directly to the vertical wall in a variety of configurations. The vertical wall not only serves to provide tensile resistance to the soil reinforcing elements but also prevents erosion of the MSE.
Although there are several methods of attaching soil reinforcing elements to facing structures, it nonetheless remains desirable to find improved attachment methods and systems that provide greater resistance to shear forces inherent in such structures.
Example embodiments may provide a system for constructing a mechanically stabilized earth structure. The system may include a soil reinforcing element having a plurality of transverse wires coupled with a pair of longitudinal wires and a wire facing having a bend formed therein to form a horizontal element and a vertical facing. The pair of longitudinal wires may have lead ends that may converge and may be coupled with a connection stud having a first end and a second end. The first end may be coupled with the lead ends and the second end may comprise a connector bent with respect to the first end. At least the connection stud and the pair of longitudinal wires of the soil reinforcing element may be coplanar. The vertical facing may have a plurality of vertical wires coupled with a plurality of facing cross wires and the connector may be coupled with at least one vertical wire of the plurality of vertical wires such that the soil reinforcing element may be configured to swivel in a horizontal plane about the at least one vertical wire.
Example embodiments may provide a method of constructing a mechanically stabilized earth structure. The method may include providing a first lift comprising a first wire facing being bent to form a first horizontal element and a first vertical facing. The first vertical facing may have a plurality of vertical wires coupled with a plurality of facing cross wires. The method may further include coupling a soil reinforcing element to at least one vertical wire of the first vertical facing using a connection stud such that the soil reinforcing element swivels in a horizontal plane about the at least one vertical wire, placing a screen on the first wire facing whereby the screen covers at least a portion of the first vertical facing and the first horizontal element, and placing backfill on the first lift to a height of the first vertical facing. The soil reinforcing element may comprise a plurality of transverse wires coupled with a pair of longitudinal wires. The pair of longitudinal wires may have lead ends coupled with the connection stud having a first end and a second end. The first end is coupled with the lead ends and the second end comprises a connector bent with respect to the first end, and at least the connection stud and the pair of longitudinal wires of the soil reinforcing element are coplanar.
Example embodiments may provide a system for constructing a mechanically stabilized earth structure. The system may include a wire facing bent to form a horizontal element and a vertical facing, a soil reinforcing element having a pair of longitudinal wires and a plurality of transverse wires coupled together, and a screen disposed on the wire facing. The vertical facing may have a plurality of vertical wires coupled with a plurality of facing cross wires. The plurality of vertical wires may include a plurality of connector leads and each connector lead may comprise a pair of vertical wires laterally offset from each other by a short distance. The pair of longitudinal wires may have lead ends coupled with a connection stud having a first end and a second end. The first end may be coupled with the lead ends and the second end may comprise a connector bent with respect to the first end. At least the connection stud and the pair of longitudinal wires of the soil reinforcing element may be coplanar. The soil reinforcing element may be coupled with a connector lead of the plurality of connector leads such that the soil reinforcing element may swivel in a horizontal plane about the connector lead.
The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
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. Additionally, 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.
In one or more exemplary embodiments, the lead ends 110 of the longitudinal wires 106 may generally converge and be welded or otherwise attached to a connection stud 112. The connection stud 112 may include a first end or stem 114 and a second end or connector 116. As illustrated, the stem 114 may include a plurality of indentations or grooves 118 defined along its axial length. The grooves 118 may be cast or otherwise machined into the stem 114 thereby providing a more suitable welding surface for attaching the lead ends 110 of the longitudinal wires 106 thereto. In an exemplary embodiment, the grooves 118 may include standard thread markings. As may be appreciated, this may result in a stronger resistance weld. In an exemplary embodiment, the connector 116 may be hook-shaped and bent or otherwise turned about 180° from the axial direction of the stem 114 resulting in the connection stud having a hook-shape configured to couple or otherwise attach to the wire facing 104, as will be described below. In another exemplary embodiment, the connector 116 may be bent such that at least the longitudinal wires 106 of the soil reinforcing element 102 and the connector 116 are coplanar.
As illustrated in
The vertical facing 122 may include a plurality of vertical wires 128 extending vertically with reference to the horizontal element 120 and equidistantly spaced from each other. In an exemplary embodiment, the vertical wires 128 may be vertical extensions of the horizontal wires 124 of the horizontal element 120. Furthermore, the horizontal connector leads 124a-h from the horizontal element 120 may also extend vertically into the vertical facing 122, referred to as vertical connector leads 124a-h and including a pair of vertical wires 128 laterally offset from each other by a short distance, such as about 1 inch. The vertical connector leads 124a-h may be configured to provide a visual indicator to an installer as to where a soil reinforcing element 102 may be properly attached, as will be described in greater detail below. The vertical facing 122 may also include a plurality of facing cross wires 130 vertically offset from each other and welded or otherwise attached to both the vertical wires 128 and vertical connector leads 124a-h. In at least one exemplary embodiment, the vertical wires 128 may be equidistantly separated by a distance of about 4 inches and the facing cross wires 130 may be equidistantly separated from each other by a distance of about 4 inches, thereby generating a grid-like facing composed of a plurality of square voids having a 4″×4″ dimension. As may be appreciated, however, the spacing between adjacent wires 128, 130 may be varied to more or less than 4 inches to suit varying applications.
As illustrated in
The wire facing 104 may further include one or more struts 304 operatively coupled to the wire facing 104. As illustrated, the struts 304 may be coupled to both the vertical facing 122 and the horizontal element 120. In an exemplary embodiment, the struts 304 may be coupled to the wire facing 104 before backfill is added thereto. Once in position, the struts 304 may allow backfill to be positioned on both the horizontal elements 120 and vertical facings 122 until reaching the top or vertical height of the vertical facing 122. The struts 304 may allow installers to walk on the MSE structure, tamp the MSE structure, and compact the MSE structure fully before adding a new lift or layer, as will be described below.
During the placement of backfill, and during the life of the wire facing 104, the struts 304 may prevent the vertical facing 122 from bending past a predetermined vertical angle. For example, as illustrated in
In an exemplary embodiment, the struts 304 may be coupled to the top-most cross wire 130a of the vertical facing 122 at a first end 306a of the strut 304 and to the terminal wire 126b of the horizontal element 120 at a second end 306b of the strut 304. As illustrated in
Each strut 304 may be prefabricated with a connection device (not shown) at each end 306a,b configured to fastened or otherwise attach the struts 304 to both the horizontal element 120 and the vertical facing 122. In an exemplary embodiment, the connection device may include a hook that is bent about 180° back upon itself and coupled to the ends 306a,b of the struts 304. In another exemplary embodiment, the connection device may include a wire loop disposed at each end 306a,b of the struts 304 that may be manipulated, clipped, or tied to the both the horizontal element 120 and the vertical facing 122. As may be appreciated, however, the struts 304 may be coupled to the horizontal element 120 and the vertical facing 122 by any practicable method or device known in the art.
In an exemplary embodiment, the vertical facings 122 of each lift 308, 310 may be substantially parallel and continuous, thereby constituting an unbroken vertical ascent. In another exemplary embodiment, however, the vertical facings 122 of each lift 308, 310 may be laterally offset from each other. For example, the disclosure also contemplates exemplary embodiments where the vertical facing 122 of the second lift 310 may be disposed behind or in front of the vertical facing 122 of the first lift 308, and so on until the MSE wall is built to its full height.
Because of the added strength derived from the struts 304, each lift 308, 310 may be free from contact with any adjacent lift 308, 310. Thus, in an exemplary embodiment, the first lift 308 may have backfill placed thereon up to or near the vertical height of the vertical panel 122 and compacted so that the second lift 310 may be placed completely on the compacted backfill of the first lift 308 therebelow. In prior art, the vertical face 122 of the first lift 308 is tied into the vertical face 122 of the second lift 310 to prevent an outward displacement of the first lift 308; however, exemplary embodiments may allow each lift 308, 310 to be relatively free from physical engagement with each other. This may prove advantageous during settling of the MSE structure. For instance, where adjacent lifts 308, 310 are not in contact with each other, the wire facings 104 may settle without causing the adjacent lifts 308, 310 to bind on each other, which may potentially diminish the structural integrity of the MSE structure. This may not, however, mean that the lifts may not be coupled together. Instead, exemplary embodiments contemplated herein also include configurations where the distal ends of the vertical wires 128 of the first lift 308 include hooks or other elements that may be attached to the succeeding lift 310, without departing from the scope of the disclosure.
The soil reinforcing element 102 having the connection stud 112, according to exemplary embodiments disclosed above, may offer numerous advantages over prior art soil reinforcing elements. For instance, the soil reinforcing element may pivot or swivel in the horizontal plane to avoid obstructions. The connector 116 may settle with the backfill by attaching the connector 116 to a vertical wire 128 at a location below a facing cross wire 130 of the vertical facing. Also, the connector 116 may be attached to a “high” load vertical J-bar. The orientation of the connector 116 may allow the wire facing 104 to lay “flat” when stacked in a bundle to aid in shipping.
The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.