This application claims the benefit of U.S. patent application Ser. No. 09/958,369, filed Oct. 6, 2001, and entitled “RETAINING WALL SYSTEM WITH INTERLOCKED WALL-BUILDING UNITS,” now abandoned, which is incorporated herein by reference.
The invention pertains to retaining walls and to methods of constructing retaining walls. In particular, it pertains to retaining walls built of units such as sand/soil bags or hardenable units such as fresh clay bricks, wherein the units in adjacent courses are connected together.
Retaining walls are used in a wide variety of civil engineering and landscaping applications, for example to support slopes and embankments for highways and railways, support noise barriers, etc. Retaining walls are commonly made having a supporting face structure made of interconnecting blocks with soil or other fill placed and compacted in back of the wall, and with sheets of geogrid laid in the fill at various levels, extending back from the wall. The geogrid sheets, which stabilize the backfill, are often attached to the interlocking blocks.
It is known to build retaining walls of sandbags instead of interlocking blocks to hold the backfill. In the prior art, sandbags in retaining walls are not attached to each other, relying essentially on their mass to stabilize the wall. This limits the steepness and the height of retaining walls that can be build with sandbags. Sandbag retaining walls, in the prior art, are normally temporary, rather than permanent, structures.
Also, it is known to build retaining walls with blocks of various kinds. Such blocks, in the prior art, generally need to be made with interfitting parts or be affixed by concrete or the like in order to make a secure stable retaining wall.
Japanese Abstract JP-A06-322730 published Nov. 22, 1994 shows the use of a disc-like solid with a projection on both sides to prevent slippage between bags of ready-mix concrete in a retaining wall. However, such device can prevent slippage only between two vertically-adjacent bags. Japanese abstract JP-A-59-048525 published Mar. 19, 1984 shows the use of sand and soil bags provided integrally on the ends of water-permeable sheets which extend into fill in back of a vertical bank.
The invention provides a permanent retaining wall structure in which the wail-building units, such as sand/soil bags, used to make the face of the structure are attached to wall-building units in adjacent courses, and preferably to geogrid sheets. The attachment is done by means of a plate having projections on both sides thereof which protrude into the wall-building units in adjacent courses, and which also protrude through the holes in the geogrid sheets, stabilizing the retaining wall structure and backfill.
In one embodiment of the invention, the wall-building units are bags of sand, soil or similar fill material. In this specification, “sand/soil bag” means a bag filled with any suitable fill material, including sand, soil, mixtures thereof and including fill mixed with seeds for grass or other plants. In another embodiment, the wall-building units are units that harden, or that can be made to harden, after they are placed in the wall and interconnected together by means of the attachment devices of the invention. Examples are freshly formed bricks of clay or similar material prior to their hardening; or bags of cement or a mixture of cement and aggregate that can be made to harden by wetting them and allowing them to cure after they are set in place. Such wall-building units are collectively referred to as “hardenable building units” in this specification. Thus “wall-building units” can be either “sand/soil bags” or “hardenable building units,” the distinction being that the former have fill that remains friable after the wall is made and the latter harden or cure after the wall is constructed, forming rigid units.
The invention provides a retaining wall structure comprising a first plurality of wall-building units positioned adjacent to one another forming a first, horizontally-extending course; a second plurality of wall-building units positioned adjacent to one another above the first course forming a second course; and interconnecting members placed between the first and second courses attaching them together. The interconnecting members comprise a plate having an upper side and a lower side, a first set of projections on the lower side and a second set of projections on the upper side, the projections being capable of protruding into a wall-building unit. The interconnecting members are positioned between the wall-building units of the first and second courses so that the first set of projections protrudes into a unit in the lower course and the second set of projections protrudes into a unit in the upper course. The interconnecting members may also be placed on the ground or on a footing, under the base course of wall-building units.
The retaining wall structure can optionally comprise a sheet of geogrid extending from between adjacent courses into backfill behind the retaining wall. The geogrid sheet is positioned so that projections of the interconnecting member protrude through holes in the sheet.
The invention also provides an interconnecting member for attaching a first horizontally extending course of wall-building units to a second horizontally-extending course positioned vertically adjacent to the first course. The member comprises a plate having an upper and lower side with a set of projections on each side capable of protruding into a wall-building unit. The projections can also serve the function of providing attachment means for a sheet of geogrid, but preferably, the interconnecting member includes a set of geogrid-holding members on the upper side of the plate that are shaped and adapted specifically to protrude through holes in a sheet of geogrid. There may be retaining caps affixed to the geogrid-holding members for retaining a sheet of geogrid thereon. The interconnecting member may also have a flange around the base of each projection on the upper side of the plate, having a lip for sealing against a wall-building unit.
The retaining wall structure can also optionally include cover plates to improve the durability and appearance of the wall.
The invention also provides a method of constructing a retaining wall structure having a plurality of courses of wall-building units. The method comprises the steps of placing a first plurality of wall-building units adjacent to one another to form a first, horizontally-extending course; placing interconnecting members on the first course, the interconnecting members having a first set of projections on their lower side and a second set of projections on their upper side, such that the projections in the first set protrude into wall-building units in the first course of wall-building units; and placing a plurality of wall-building units adjacent to one another to form a second course above the first course, such that the projections of the second set protrude into wall-building units of the second course. The method of constructing a retaining wall can include the step of placing a sheet of geogrid extending from between the courses of wall-building units into the backfill, with projections of the interconnecting member protruding through holes in the geogrid to anchor it in place.
a) to (e) illustrate steps in a method of constructing a retaining wall structure;
a) to (c) are perspective views of the cover plate assembly and the parts thereof;
Referring to
Backfill 16 is compacted behind and supported by sand/soil bags 14. Geogrid sheets 18 extend horizontally back into the backfill from between courses of sand/soil bags 14, affixed thereto as described hereunder. Interconnecting members 26 are placed between the adjacent courses of sand/soil bags 14.
Referring to
Referring to
The interconnecting members 26 are also used to anchor geogrid sheets to the sandbags. Geogrid sheets 18 are known and commercially available plastic mesh products commonly used for soil reinforcement Referring to
Instead of being placed over an interconnecting member 26, the geogrid sheet can be placed directly on top of a course of sand/soil bags and the interconnecting members placed over it, with the projections 24 on the lower side of the member 26 protruding down through holes 28 in the geogrid sheet and into the bags. In other words, the geogrid can be placed under the interconnecting member instead of over it.
Geogrid sheets are installed at selected levels during the construction of the wall, for example on top of every third course of bags, or as required for a particular application.
Then, a row of interconnecting members 26 is placed along the uppermost course of bags 14 and a sheet of geogrid 18 is placed on it, extending back along the surface of the backfill 16 (
In some applications, it is desirable to place interconnecting members 26 on the ground under the base course of bags 14. Here, a row of interconnecting members 26 is placed on the leveling pad or concrete footing and the first or base course of bags 14 is placed on it. The wall is then further constructed as described above. This reduces movement or slippage of the base course of bags and assists in their being properly positioned.
According to one embodiment of the invention, bags 14 include seeds of grass or other ground covers mixed in their fill. After the retaining wall is built, the bags are watered, naturally or artificially, and the ground cover plants grow out of the bags, providing a green foliage face on the retaining wall.
According to another embodiment of the invention, the bags do not include seeds but are instead made in shapes which, in a completed wall,) will form an attractive wall face. For example, the face side of the bags can be rectangular, square or hexagonal, to permit the construction of a wall face with any of various interlocking patterns. The bags can also be of transparent material, such as plastic, and in such case the fill can be decoratively colored. For example, the fill can be green-colored gravel.
Two further alternate configurations are shown in
In another embodiment of the invention, the wall-building units are hardenable building units. For example, the hardenable building units can be freshly-formed bricks of clay, concrete or similar material used prior to their hardening; or they can be bags of cement or a mixture of cement and aggregate that can be made to harden by wetting them and allowing them to cure after they are set in place; or any similar material that is sufficiently soft to be penetrated by the projections of the interconnecting members but which hardens (for example by drying out, as in the case of a clay or concrete brick) or that can be made to harden (for example by wetting and then allowing to cure, as in the case of a bag of cement or cement and aggregate) after it is set in place. The hardenable building units must be firm enough at the time of use to retain their form and to be stackable, i.e. capable of being stacked without collapsing or breaking. In the case of freshly-formed clay or concrete blocks, such blocks should be semi-hardened. A retaining wall made in accordance with this embodiment of the invention, using hardenable building units, is made in the same manner as described above for retaining walls where the wall-building units are sand/soil bags. Here, the method of making a retaining wall includes the additional step of allowing, or causing, the hardenable building units to harden. For example, where the hardenable building unit is a clay brick, it is used in the construction of the retaining wall when it is still soft enough to be easily penetrated by the projections 24 of plate 122. As the wall is built, the clay bricks gradually cure and harden. Where the hardenable building unit is a bag of cement, or cement and aggregate, it is used in the same manner as the sand/soil bags as described above to construct the retaining wall; then, the bags are wetted and allowed to cure, causing the cement or cement and aggregate in each bag to harden. As described above in respect of the construction of walls made from sand/soil bags, a row of interconnecting members 26 can also be used under the base course of hardenable building units.
Projections 64 are preferably formed in plate 62 by pressing and molding the plate, resulting in a corresponding depression 68 in the opposite side of the plate. However, the projections can also be solid, as in the embodiment of
As shown in
The interconnecting member 60 can be configured so that, in use, the geogrid-holding members 66 are covered by the sand/soil bags that are above them. In this case, the distance between the row of members 66 and the row of projections 64 that is nearest to it is relatively small, so that the sand/soil bag on top of the interconnecting member 60 covers both the projections 64 and the geogrid-holding members 66. Alternatively, the interconnecting member 60 can be configured so that, in use, the geogrid-holding members 66 are not covered by the sand/soil bags that are above them. In this case the distance between the row of members 66 and the row of projections 64 that is closest to it is relatively large, so the section of the plate 62 bearing members 66 extends beyond sand/soil bags and is not covered by them. In this case, holes (not illustrated in the drawings) can be provided in plate 62 in the region between the row of geogrid-holding members 66 and the nearest row of projections 64 to facilitate water drainage through the retaining wall, and also to economize on material, i.e. to permit cheaper fabrication of the interconnecting members. It will be understood that these features, though described in relation to the embodiment of
It will be apparent that the geogrid-holding members 66 of the interconnecting member 60, 80 is a feature that can also be incorporated into the structure of the embodiments of the interconnecting member shown in
Referring first to
Referring next to
Interconnecting members according to the invention are also used in applications which do not include the use of geogrid, or in which geogrid is used but is not attached to the retaining wall. For such applications, the interconnecting member does not include geogrid-holding members as described above.
Retaining walls of the invention can optionally include cover plates which attach to the face of the wall. Referring to
Cover plate assembly 30 has particular application to retaining walls of the invention when made of sand/soil bags, or of hardenable building materials such as bags of cement and aggregate (rather than to walls made of freshly-formed molded blocks) to improve the durability and appearance of such walls. A cover plate assembly is attached to the wall by pressing the pointed ends of rods 44 through the bags until the inner side of the cover plate 32 abuts the wall. The sinuous portions 46 of the rods 44 enhance the engagement of the rods in the fill material of the sand/soil bags or in the material of the hardenable building units. Additional cover plate assemblies are affixed to the wall, abutting each other, to form a substantially complete cover. As shown in
Rods 44 can optionally have different means for engagement in the fill material of the sand/soil bags or in the hardenable building units instead of sinuous portion 46. For example rods 44 can have threads, ridges or other structures for engagement.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. For example, the interconnecting member can be made flexible to conform to the shape of the wall-building units. The projections on it can be barbed, to enhance their attachment to the wall-building units, and they can project at angles other than the vertical from the plate. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
Number | Date | Country | Kind |
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2268509 | Apr 1999 | CA | national |
2000-0002413 | Jan 2000 | KR | national |
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Number | Date | Country | |
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20050005566 A1 | Jan 2005 | US |