WO2003093597A2

WO2003093597A2 - Precast concrete retaining wall and method

Info

Publication number: WO2003093597A2
Application number: PCT/US2003/013534
Authority: WO
Inventors: Kenneth L. Shaw
Original assignee: Shaw Kenneth L
Priority date: 2002-05-01
Filing date: 2003-04-30
Publication date: 2003-11-13
Also published as: WO2003093597A3; AU2003243182A1; AU2003243182A8

Abstract

A retaining wall system and method for constructing same using a combination of anchoring elements connected to retaining wall panels (12) and extending into fill (14) behind the wall to counteract overturning forces. Flat, or sheet-like elements (19) are used, and also strips or other narrow elements (16) where a vertical or other obstruction (24) in the fill hinders placement of the flat elements. Both types of anchoring elements may be connected to a single panel, or to various panels of the retaining wall system.

Description

PRECAST CONCRETE RETAINING WALL AND METHOD

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention relates to methods of and an apparatus and system for retaining wall construction and, more particularly, but not by way of limitation, to a system and method for constructing retaining walls around vertical obstructions.

HISTORY OF RELATED ART

Retaining walls require support in order to remain erect as originally positioned. Such walls typically stand on a ground region and retain behind it an earthen section or other fill material, which earthen section would otherwise form a natural slope in place of the retaining wall. Such retaining walls are typically vertical, or may be slightly inclined to add additional support to retain the earth behind the retaining wall and maintain its structural integrity.

A generally vertical retaining wall may begin to pivot about its underlying foundation as the mass of the earth retained behind it presses against it, tending to force it to pivot, deform or slip. Some stabilization techniques to resist this force, and assemblies and methods therefor, are shown in patents addressing reinforced earth stabilization, retaining wall assemblies, embankment systems and related anchoring techniques for backfilled wall structures. These patents include U.S. Patent Nos. 5,820,305, 5,797,706, 5,791,826, 5,531,547, 5,178,492, 5,144,779, 5,033,912, 4,983,076, 4,710,062, 4,653,962 and 4,564,867. It may be seen from these teachings that structural backfilling is an integral part of contemporary retaining wall construction. Membranes, wire mesh, elongate members, anchor rods or the like are known to secure a retaining wall system.

Many of the above-referenced patents address the types of backfill assemblies and techniques for securing wire mesh and other anchoring elements to the retaining wall section. With the mesh or other anchoring elements secured by the backfilled embankment, they permit the retaining wall section to resist the force of the fill retained behind it, maintaining its original vertical or inclined orientation and position of the wall panel. Mesh and the like are critical in meeting this design goal.

Wire mesh is much more economical than many forms of anchoring members which extend rearwardly of retaining wall panels, such as struts and the like. However, one or more vertical obstacles often interfere with the placement of the anchoring elements, such as wire mesh, creating cost and efficiency problems. For example, in the construction of a bridge abutment, it is typical to have concrete pillars with concrete piers buried within the earth supporting the bridge abutment above. U.S. Patent No. 4,564,967 illustrates such pillars supporting a beam seat, which itself supports bridge beams. Such piers may be adjacent, or near, to the retaining wall section. There may be limited or no free area in the fill behind the wall for the placement of wire mesh and the like for a retaining wall constructed adjacent to such piers and/or columns. It is known but not convenient to cut or deform wire mesh sections to permit placing a section around such vertical obstructions.

Other anchoring elements are also known, including a tensioning element attached to a deadman placed in the filled region, fabric strips, struts, metal strips, including such strips with ribbing in various arrangements, such as transverse, helical, angled, or in a chevron pattern, or ribbing joined to an elongated metal portion. Linear anchoring elements, such as strips or struts, to structurally secure retaining walls are often more expensive to fabricate, install and utilize in backfill configurations. Thus, wire mesh is used in those areas where it may be.

It would be an advantage, therefore, to provide a retaining wall system where wire mesh could be primarily utilized without the need to trim and/or modify it in the area of vertical obstructions such as pillars, posts, plumbing, underground structures and the like, which interfere with retaining wall assemblies. The present invention provides such an improved method and apparatus for a retaining wall construction by utilizing a wire mesh or another planar anchoring element in conjunction with pivotal struts or strips or other linear anchoring elements extending rearwardly from a retaining wall section. In this manner, a particular retaining wall panel will receive wire mesh or another planar anchoring element and/or a strip to secure the panel. The strip may be pivoted to form an angle from a directly rearward-facing position, around the vertical obstruction, in an efficient and cost-effective manner for a retaining wall assembly.

SUMMARY OF THE INVENTION

The present invention relates to methods of and an apparatus for retaining wall construction. More particularly, one aspect of the present invention includes a retaining wall system comprising a retaining wall, for use in retaining a filled region in which there is one or more vertical obstructions. The retaining wall system includes at least one panel including a front face and a rear face and at least one of a first type of anchoring element for connecting to the at least one panel. The system also includes at least one of a second type of anchoring element for connecting to the at least one panel. The second type of anchoring element for anchors the at least one panel if an obstruction prevents utilization of the first type of anchoring element.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and apparatus of the present invention may be obtained by reference to the following detailed description when taken in conjunction with the accompanying Drawings wherein:

FIGURE 1 is a top plan view of one embodiment of a retaining wall system and method in accordance with the principles of the present invention;

FIGURE 2 is a partial perspective cutaway view of the retaining wall system of various sections of FIGURE 1 with the earthen areas removed for purposes of demonstration and visibility of the embodiment of the present invention;

FIGURE 3 is a perspective view of another aspect of the retaining wall system with the earthen areas removed for purposes of demonstration and visibility of an embodiment of the present invention;

FIGURE 4A is a side elevation view depicting a step in carrying out a method of the present invention;

FIGURE 4B is a top plan view depicting the step in FIGURE 4A; FIGURES 4C and-4D are side elevation views depicting steps in carrying out a method of the present invention;

FIGURE 4E is a top plan view depicting the step in FIGURE 4E; and

FIGURE 4F is a side elevation view depicting steps in carrying out a method of the present invention.

DETAILED DESCRIPTION

Referring first to FIG. 1, this top plan view depicts one embodiment of a retaining wall system constructed in accordance with the principles of the present invention. The retaining wall system 10 comprises a plurality of panels 12a-12i (referred to generically as panel 12) retaining an earthen region 14. The panels 12 are secured in place by a plurality of linear anchoring elements 16 and mesh anchoring elements 19, with individual panels 12a-12i secured by one or a combination of the linear anchoring elements 16 and the mesh anchoring elements 19. Piers 24 and conduit 22, both examples of vertical obstructions, are shown in the region behind the retaining wall panels and within earthen region 14. Piers 24, necessary for support of an adjoining structure, such as a bridge, and conduit 22, hinder placement of mesh anchoring elements 19, and require specific placement of at least some of the linear anchoring elements 16,

Still referring to FIG. 1, panels 12a-12i have anchoring elements 16, 19 attached thereto and extending generally rearwardly into the earthen region 14. Typically, a plurality of the anchoring elements 16, 19 are attached to the retaining wall panels 12. In this embodiment, each panel 12 uses four anchoring elements 16, 19, one each in the upper left, upper right, lower left and lower right quadrants, as perspective view FIG. 2 depicts. However, the panels 12 may use other numbers of, and arrangements of anchoring elements such as two-by-three or three-by-three array. FIG. 2 depicts upper 33 and lower tiers 31 of the panels 12, but, for clarity, omits detail for all but the second tier 33.

Returning to FIG. 1, mesh anchoring elements 19 may be a welded wire gridwork panel, formed from wires and rods joined at generally right angles for a rectangular cross- hatched pattern. The mesh anchoring elements 19 may also comprise some other form of metal mesh, or a geo-synthetic material, such as geogrid. The mesh anchoring elements 19 typically comprise a perforated, or perforate, material, but could also comprise a geo- synthetic material such as a fabric, or other broad, flat soil reinforcement mechanism. This aids in forming a mechanical interlock of the fill material in or through the relatively flat mesh surface, transferring tension in the mesh to the fill. The mesh anchoring elements 19 are typically in the form of a substantially rectangular panel. The mesh anchoring elements 19 are connected to the panels 12 using means known within the art. Several connecting structures for doing so include those disclosed in U.S. Patent Nos. 4,324,508, 4,449,857, 4,725,170, 4,929,125 and 6,186,703 Bl. One structure includes vertically-oriented loops formed into the panels 12, through which a rod is placed, connecting the panel 12 to the mesh anchoring elements 19 by corresponding loops in the mesh. Another includes horizontally-oriented loops extending from the panels 12, through which longitudinally-extending wires forming the mesh pass, joining the mesh anchoring elements 19 to the panel 12. Another uses a threaded connection between a fitting on the mesh and a fitting formed into the panel 12. Yet others use hook-and-eye combinations, or a clevis and pin arrangement with a loop formed into the end of the wire mesh for the pin. Connectors 20 transmit tension provided by the mesh anchoring elements 19 to counteract outward force applied by the earthen region 14 to the panels 12.

As shown in FIG. 1, mesh anchoring elements 19 are used for those panels 12, or portions of those panels 12, not obstructed by piers 24 or conduit 22. Thus, panels 12a, 12b, 12e, 12i and part of 12h use mesh anchoring elements 19. As shown in FIGS. 1 and 2, the mesh anchoring elements 19 extend substantially directly rearwardly from a panel 12, and are fastened together via the connector 20. The mesh anchoring elements 19 are shown as directly rearward of the panel 12 in a substantially horizontal direction. However, the mesh anchoring elements 19 may also be placed at an incline to the vertical (as shown in FIG. 3). In this embodiment, as best shown in FIG. 2, the panel 12e is connected via connectors 20 to four mesh anchoring elements 19, one each in the upper right and lower right, and upper left and lower left quadrant connection points. Connection and placement of the mesh anchoring element 19 for the panel 12e is typical for panels 12a, 12b and 12i (not shown). As mesh anchoring elements 19 are fixed in a direction substantially normal to the panel face (e.g. normal N from panel 12b in FIG. 1), it is apparent that obstructions such as piers 24 and conduit 22 would prevent their proper placement, without cutting, bending or otherwise reconfiguring the mesh anchoring elements 19. This is typically undesirable because of the increased time and cost involved. The linear anchoring elements 16 are used when vertical or horizontal obstructions are present because they may be placed where an obstruction would hinder or prevent placement of a mesh anchoring element 19, or would require time-consuming trimming or bending of such mesh element.

Linear anchoring elements 16 may take several forms, such as a tensioning element attached to a deadman placed in the filled region, fabric strips, metal or plastic struts, metal or plastic strips, including such strips with ribbing in various arrangements, such as transverse, helical, angled, or in a chevron pattern, or ribbing joined to an elongated metal portion, and include those disclosed in U.S. Patent Nos. 6,079,907, 5,890,843, 5,797,706, 5,033,912, 4,710,062, 4,116,010. Linear anchoring elements 16 typically form a mechanical interlock between the fill material of the earthen region 14 and surface irregularities, or surface configuration, of the linear anchoring elements 16. This is in addition to the frictional resistance formed between the fill and the surface of the linear anchoring element 16. Linear anchoring elements 16 may also have a non-circular flat or flattened cross-section, providing a relatively larger frictional surface area that faces upward or downward. This presents a larger normal area to the interlocking and frictional effects. Linear anchoring elements 16 are connected to the panels 12 which permit the panel to transmit outward force from the earthen region 14 to the linear anchoring elements 16. Connectors 17 also permit the linear anchoring elements 16 to extend into the earthen region 14 from the panel 12 at an angle to the normal N (non-perpendicular to the panels 12), as shown in FIG. 1 (panel 12g). Such connectors 17 are well known in the art, and include those disclosed in U.S. Patent Nos. 4,116,010, 4,710,062, 5,890,843. The connectors 17 include a hook-and-loop arrangement, with one fixed to the panel 12, a clevis and pin combination, with a hole formed into the linear anchoring element 16 to retain the pin. Linear anchpring elements 16 are connected to the panels 12c, 12d, 12f, 12g and, in part, 12h. As shown in FIGS. 1 and 2, in this embodiment, four linear anchoring elements 16 are connected to panel 12f, one each in the upper right and lower right, and upper left and lower left quadrant connection points. As with the mesh anchoring elements 19, however, other arrangements such as two-by-three or three-by-three are possible. The linear anchoring elements 16 are connected to the panel 12f using connectors 17. As shown in FIGS. 1 and 2, the linear anchoring elements 16 extend into the earthen region 14 from the panel 12g so as to avoid the pier 24 which would prevent placement of the mesh anchoring elements 19 on the panel 12g. Note that the linear anchoring element 16 in the upper right quadrant of panel 12g is placed at angle to normal N to avoid the pier 24, as are other linear anchoring elements 16 on other panels 12, as depicted. Some linear anchoring elements 16 may be placed facing directly rearward while still avoiding any obstruction, because they are not as wide as mesh anchoring elements 19. Connection and placement of the linear anchoring elements 16 described for the panel 12g is typical for the panels 12c, 12d and 12f.

An obstruction may prevent placement of the mesh anchoring elements 19 on only part of a panel 12. Remaining with FIGS. 1 and 2, conduit 22 prevents placement of upper left and lower left elements for the panel 12h, but does not prevent the use of the mesh anchoring elements 19 on the right quadrants. As shown in FIG. 1, the mesh anchoring elements 19 and connectors 20 are connected on the right, where they are not obstructed, while linear anchoring elements 16 and connectors 17 are connected on left quadrants. Thus, a mix of anchoring element types 16, 19 may be utilized for a given panel 12. Connection and placement of the mesh anchoring elements 19, connectors 20, linear anchoring elements 16 and connectors 17 are otherwise as described above.

In addition, the present invention may also be employed where a vertical or horizontal obstruction obstructs only some panels 12 in a vertical grouping. Turning to FIG. 3, retaining panels 12k and 121 are shown as a vertical grouping in a substantially vertical array of panels 12 forming a retaining wall system 10'. Faces 13 of the panels 12 of the retaining wall system 10' form angle with vertical V, Partial obstruction 23 extends behind the lower panel 121, preventing placement of the mesh anchoring elements 19. But as the obstruction .23 does not extend behind the upper panel 12k, mesh anchoring elements 19 may be fastened to the upper panel 12k. Thus, the lower panel 121 has six linear anchoring elements 16 in a two-by-three array generally rearwardly into the earthen region 14. The linear anchoring elements 16 are attached using connectors 17 as described above. If the obstruction 23 partially obstructs the placement of the linear anchoring elements 16, the linear anchoring elements 16 may be pivoted at an angle to face 13 of the lower panel 121, as shown in FIG. 1. Connection and placement of the mesh anchoring elements 19, connectors 20, linear anchoring elements 16 and connectors 17 are otherwise as described above.

Turning to FIGS. 4A-4F, a retaining wall system using both linear anchoring elements 16 and mesh anchoring elements 19 in the same structure may be constructed according to the following process. A plurality of stackable panels 12 are shown in FIGS 2 and 3. Next, a lower tier 31 of the array of panels 12 is disposed as shown in FIGS. 4A and 4B. This may be done at the bottom of an existing embankment 15 in front of which the earthen region 14 will be formed within retaining wall system 10. A footing may optionally be constructed for the array of panels 12 to be placed thereon. This is well known in the art. Next, as shown in FIG. 4C, the earthen region 14 is backfilled to create a layer 14' of soil or other fill behind lower tier panels 31 to a level on panel face 13 that is substantially as high as the lowest row of connection points. Connectors may be connectors 17 for the linear anchoring elements 16 or connectors 20 for the mesh anchoring elements 19. As shown in FIGS. 4D and 4E, linear anchoring elements 16 are used for panel 12' because of obstruction pier 24. Linear anchoring elements 16 are placed on top of the first layer of fill 14', preferably at a substantially horizontal angle and connected using connectors 17 to the panel 12'. If necessary, the linear anchoring element 16 is pivoted at an angle to the normal of face 13, as is shown in FIG. 4E. The mesh anchoring elements 19 are used for the panel 12" because it is unobstructed. Mesh anchoring elements 19 are placed on top of the first layer of fill 14', preferably at a substantially horizontal angle and connected to panel 12" using connectors 20. Optionally, for either mesh anchoring elements 19 or linear anchoring elements 16, the anchoring element 16, 19 may be attached to the panel 12' or 12" via its appropriate connector prior to backfilling the soil. In that case, the anchoring elements are 16, 19 retained in a substantially vertical position to permit backfilling substantially up to the level of the connector, or another position permitting backfilling, such as draping a flexible planar or linear anchoring element up and over the panel. Once the backfilling step is completed, anchoring elements 16, 19 are rotated or moved downwardly to a preferably horizontal position on the top of the backfill layer.

If further backfill height is desired, these steps are repeated for any higher rows of connectors in the array of connectors for the lower tier 31 of panels. As shown in FIG. 4F, this step is repeated once for the lower tier 31, thus creating two layers of soil and two rows of anchoring elements. Then, a second tier 33 of panels 12 is stacked on top of lower tier 31. Once the upper tier 33 is in place, the backfilling, connecting and anchoring steps are repeated with further layers of fill 14" and 14'", until the embankment and retaining wall reach the desired height. Of course, further tiers may be placed above the lower and second tier 31, 33 as necessary. In addition, it is well known in the art how to construct a corner in a retaining wall structure. Two adjacent panels 12, on a front and side of a structure, 12c, 12d and 12f, 12g, as shown in FIGS. 1 and 2, are butted together to form a corner. Alternatively, a monolithic corner-piece may be used to form a corner, with the adjacent panels 12 butted up against the corner-piece (not shown).

Claims

WHAT IS CLAIMED IS:

1. A retaining wall, for use in retaining a filled region encompassing one or more vertical obstructions, comprising: at least one panel including a front face and a rear face; at least one of a first type of anchoring element for connecting to said at least one panel; and at least one of a second type of anchoring element for connecting to said at least one panel, said second type of anchoring element for anchoring said at least one panel if an obstruction prevents utilization of said first type of anchoring element.

2. The retaining wall of claim 1, wherein said first type of anchoring element comprises at least one of mesh and geogrid material.

3. The retaining wall of claim 1, wherein said second type of anchoring element comprises at least one of fabric strips, metal strips, plastic strips, ribbed strips, metal struts, and plastic struts.

4. The retaining wall of claim 1, wherein said rear face of said panel is operable to receive at least one of said first type of anchoring element and said second type of anchoring element.

5. The retaining wall of claim 1, wherein said panel is operable to receive said first type of anchoring element and said second type of anchoring element.

6. The retaining wall of claim 1, further comprising: connectors integrally formed on the rear face of said at least one panel, said connectors for fastening to at least one of said first type and said second type of anchoring element.

7. The retaining wall of claim 5, wherein at least one of said first type and said second type of anchoring element are pivotably connected to said at least one panel to pivot about a substantially vertical axis.

8. A method of constructing a retaining wall for retaining a filled region encompassing one or more obstructions therein, comprising the steps of: providing a first tier of panels for retaining a filled region including at least one obstruction; providing at least one of a first type of anchoring element for connecting to at least one panel of said first tier of panels; providing at least one of a second type of anchoring element for connecting to at least one panel of said first tier of panels; and anchoring said at least one panel by said second type of anchoring element if said at least one obstruction prevents utilization of said first type of anchoring element.

9. The method of claim 8, further comprising the step of filling the area behind the first tier panels with a fill material substantially to the level of a lowest connecting point of said at least one panel.

10. The method of claim 8, wherein said step of providing at least one of a first type of anchoring element comprises the step of providing at least one of a mesh and a geogrid material.

11. The .method of claim 8, wherein said step of providing at least one of a second type of anchoring element comprises the step of providing at least one of fabric strips, metal strips, plastic strips, ribbed strips, metal struts, and plastic struts.