Patent Grant
6862856
The invention relates generally to earth retaining walls and masonry blocks that may be used in construction of such retaining walls. More specifically, the invention relates to a corner masonry block for use in forming a corner of a segmental retaining wall system, as well as to a segmental retaining wall utilizing such corner masonry blocks.
Segmental retaining walls commonly comprise courses of modular units (blocks). The blocks are typically made of concrete. The blocks are typically dry-stacked (no mortar or grout is used), and often include one or more features adapted to properly locate adjacent blocks and/or courses with respect to one another, and to provide resistance to shear forces from course to course. The weight of the blocks is typically in the range of ten to one hundred fifty pounds per unit.
Segmental retaining walls commonly are used for architectural and site development applications. Such walls are subjected to high loads exerted by the soil behind the walls. These loads are affected by, among other things, the character of the soil, the presence of water, surcharge, and seismic loads. To handle the loads, segmental retaining wall systems often comprise one or more layers of soil reinforcement material extending from between the courses of blocks back into the soil behind the blocks. The reinforcement material is typically in the form of geosynthetic reinforcement material such as geogrid or geotextile fabric. Geogrids often are configured in a lattice arrangement and are constructed of polymer fibers or processed plastic sheet material (punched and stretched, such as described, for example, in U.S. Pat. No. 4,374,798), while geotextile fabrics are constructed of woven or knitted polymer fibers. These reinforcement members typically extend rearwardly from the wall and into the soil to stabilize the soil against movement and thereby create a more stable soil mass, which results in a more structurally secure retaining wall. In other instances, the reinforcement members comprise tie-back rods that are secured to the wall and which extend back into the soil or into rock.
Although several different forms of reinforcement members have been developed, opportunities for improvement remain with respect to attachment of the reinforcement members to the facing blocks in the retaining wall systems. As a general proposition, the more efficient the block/reinforcement connection, the fewer the layers of reinforcement material that should be required in the wall system. The cost of reinforcing material can be a significant portion of the cost of the wall system, so highly efficient block/reinforcement material connections are desirable.
Many segmental retaining wall system rely primarily upon frictional forces to hold the reinforcement material between adjacent courses of block. The systems may also include locating pins or integral locator/shear resistance features that enhance the block/reinforcement material connection to varying degrees. Examples of such systems include those described in U.S. Pat. Nos. 4,914,876, 5,709,062, and 5,827,015. These systems cannot take advantage of the full tensile strength of the common reinforcement materials, however, because the block/reinforcement material holding forces that can be generated in these systems is typically less than the tensile forces that the reinforcing materials themselves can withstand.
One of the many advantages of segmental retaining wall systems over other types of retaining walls is their flexibility. They do not generally require elaborate foundations, and they can perform well in situations where there is differential settling of the earth, or where frost heaving, for example, occurs. Even so, these types of conditions might result in differentials in the block/reinforcement material connections across the wall in systems that rely primarily on frictional connection of blocks to the reinforcement material.
In an effort to improve the block/reinforcement material connection efficiency, several current retaining wall systems have been developed that mechanically connect the reinforcement members to the blocks. In several such systems, rake shaped connector bars are positioned transversely in the center of the contact area between adjacent stacked blocks with the prongs of the connector bars extending through elongated apertures provided in the reinforcement member to retain it in place. Examples of this type of system are shown in U.S. Pat. Nos. 5,607,262 (FIGS. 1-7), 5,417,523, and 5,540,525.
These systems are only effective if the reinforcement member used is of a construction such that the cross-members that engage the prongs of the connector will resist the tensile forces exerted on the reinforcement member by the soil. There are only a few such reinforcement members currently available and, thus, the wall builder or contractor has to select reinforcement members from a limited number of manufacturers when such an attachment system is used. These systems also rely upon the prongs of the rake connectors being in register with the apertures in the reinforcement member and in contact with cross members of the reinforcement member. If the connector prongs do not line up with the apertures, installation becomes a problem. Variability in the manufacturing process of reinforcement members means that the apertures in this type of reinforcement member frequently are not perfectly regular. A solution to this problem has been to use short connector rakes that only engage several apertures, rather than long connectors that engage all of the apertures in a row across the reinforcement member. This solution eases problems, but would appear to make the connection mechanism less efficient. These devices are subject to the same criticisms as the pure friction connectors.
A third type of connector system uses a channel that, in cross-section, has a relatively large inner portion and a very narrow opening out of that portion. The reinforcement member is provided with a bead or equivalent along its leading edge. The reinforcement member is then threaded into the channel from the side, so that the reinforcement member extends out through the narrow channel opening, but the bead is captured in the larger inner portion. An example of this type of connection is shown in FIGS. 9 and 10 of U.S. Pat. No. 5,607,262. While this system overcomes differential settling concerns, it is very difficult to use in the field, and relies upon special reinforcement member configurations.
A modification of the third type of connector system described above is one in which the channel into which the bead fits is formed by a combination of the lower and adjacent upper block, so that the enlarged/beaded end of the reinforcement member can simply be laid in the partial channel of the lower blocks, and will be captured when the upper blocks are laid. This system simplifies installation, but does not resolve the aforementioned performance concerns. In a variation of this system, the end of a panel of reinforcement material is wrapped around a bar, which is then placed in a hollowed-out portion of the facing unit which is provided with an integral stop to resist pullout of the bar. Rather than being held in place by the next above facing unit, the wrapped bar is then weighted down with earth or gravel fill dumped on top of it in the hollowed out portion of the facing unit. This system is shown in U.S. Pat. No. 5,066,169. Not only is the facing unit of this system extremely complex and difficult to make, but the installation process is difficult and requires the use of very narrow panels of reinforcement material.
A solution to the problems discussed above is disclosed in patent application Ser. Nos. 09/049,627 (filed on May 27, 1998) and 09/487,820 (filed on Jan. 18, 2000), each of which is assigned to Anchor Wall Systems, Inc. The applications disclose retaining wall blocks provided with lock channels and lock flanges that provide a locking mechanism for resisting leaning or toppling of the blocks. A retaining mechanism in the form of a retaining bar interacts with a lock channel formed in the block to retain a geosynthetic reinforcement material within the channel.
A retaining wall constructed with an exterior corner presents unique challenges with respect to the use of geosynthetic reinforcement material. In a generally linear modular retaining wall structure, the forces acting on the wall tend to act in a single direction, i.e. in a direction tending to topple the wall forward. Therefore, geosynthetic reinforcement material connected to the blocks forming the linear wall and extending rearwardly from the wall and into the soil provides acceptable stability. However, with an exterior corner, the pressures resulting from the soil, surcharge, and seismic loads, are exerted on both walls of an exterior corner. Therefore, to achieve the maximum benefits from the geosynthetic reinforcement material and provide adequate stability adjacent an exterior corner, the geosynthetic reinforcement material should be connected to the blocks that form the right and left sides of an exterior corner.
An additional factor to be considered when constructing a segmental retaining wall structure is the need to offset the vertical joints in each course from the vertical joints in the courses located above and below each course. Alignment of the vertical joints in a wall is generally thought to detract from the appearance of the resulting wall structure, and it is typically common in the art to avoid vertical joint alignment.
The need to avoid vertical joint alignment in the courses of the wall structure presents difficulties at an exterior corner. First, uniform-sized corner blocks often cannot be used, due to setback of the blocks in the remaining wall structure. In addition, the blocks that form the exterior corner must also be constructed and positioned to prevent vertical joint alignment.
It can therefore be appreciated that there exists a need for a corner block, for use in a retaining wall having an exterior corner, that is constructed to permit interaction with geosynthetic reinforcement material so as to stabilize both the right and left sides of the corner, and which does not have vertical alignment of joints.
A corner block is provided for use in constructing an exterior corner of a retaining wall. The corner block is useable with geosynthetic reinforcement whereby an exterior corner of a retaining wall that includes the corner blocks described herein can be reinforced. By constructing a retaining wall with an exterior corner using the corner blocks of the invention, geosynthetic reinforcement can be used to reinforce the right side of the corner, and geosynthetic reinforcement can be used to reinforce the left side of the corner. Therefore, the right and left sides of the exterior corner can be stabilized against the forces acting on the exterior corner.
In one aspect of the invention, a corner block is provided that comprises a block body having opposed side surfaces, opposed end surfaces, a top surface and a bottom surface. At least two of the side and end surfaces that are adjacent are textured. The block also includes a channel formed in the top surface, with the channel having a longitudinal axis extending parallel to the side surfaces. The channel further includes an open end that extends through one of the end surfaces, such as the end surface that is not textured, and a closed end that terminates short of the opposite end surface. The channel is defined by at least a front wall, a rear wall opposite the front wall, and a bottom wall, and the channel is sized to receive therein a portion of an elongated retaining member such that the retaining member extends parallel to the longitudinal axis of the channel.
In another aspect of the invention, a retaining wall having an exterior corner is provided. The wall includes a plurality of courses, with each course having a first plurality of blocks forming an exterior corner, a second plurality of blocks forming a right wall portion adjacent the exterior corner, and a third plurality of blocks forming a left wall portion adjacent the exterior corner. A first reinforcement member is retained between the second plurality of blocks of mating courses and extends into soil retained by the wall. In addition, a first retainer secures the first reinforcement member to the second plurality of blocks of one of the mating courses. Moreover, a second reinforcement member is retained between the third plurality of blocks of mating courses and extends into the soil retained by the wall, and a second retainer secures the second reinforcement member to the third plurality of blocks of the mating courses.
In yet another aspect of the invention, a retaining wall includes a plurality of blocks arranged into courses and defining an exterior corner. At least one course at the exterior corner is formed from a plurality of subcourses of blocks.
The features and advantages of the invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings.
Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views,
Each block 10A, 10B comprises first and second opposed side surfaces 12, 14, first and second opposed end surfaces 16, 18, a top surface 20 and a bottom surface 22. The surfaces 12, 16 of each block 10A, 10B form exterior surfaces of the blocks that typically are visible when laid up in a wall. Accordingly, the exterior surfaces 12, 16 are typically provided with an ornamental facing to create what is generally considered to be a visually pleasing facade. The surfaces 12, 16 can be textured as a result of a splitting process used to form the blocks. Other processes that result in ornamental facings on the surfaces 12, 16 could also be used. The surface 14 of each block 10A, 10B forms an interior surface that, in use, faces to the interior of the wall.
In addition, the top and bottom surfaces 20, 22 of each block are preferably, but not necessarily, parallel to each other so that, when stacked on top of one another, an upright wall can be formed. Further, the opposed surfaces 12, 14 and 16, 18 are preferably, but not necessarily, generally parallel to each other.
Each block 10A, 10B further includes a channel 24 formed in the top surface 20. The longitudinal axis of the channel 24 extends generally parallel to the side surfaces 12, 14, with one end of the channel 24 extending through the end surface 18 and the opposite end of the channel terminating short of the end surface 16. The channel 24 is offset on the top surface 20 of the respective block, such that the channel is positioned closer to the side surface 14 than it is to the side surface 12. Alternatively, the channel 24 could be positioned such that it is positioned closer to the side surface 12 than it is to the side surface 14.
The channel 24, in use, is designed to receive an end portion of a retaining bar 90 of the type disclosed in U.S. patent application Ser. No. 09/487,820, as can be seen, for example, in
As disclosed in U.S. patent application Ser. No. 09/487,820, the reinforcement material is positively secured to the blocks by the retaining bar disposed within the channels of the blocks. However, for the corner blocks 10A, 10B, the channel 24 is designed differently from the channels in the blocks of U.S. patent application Ser. No. 09/487,820. The channel 24 simply receives the reinforcement material and the end portion of the retaining bar 90, without the securing or locking action between the retaining bar, the reinforcement material and the block channel found in U.S. patent application Ser. No. 09/487,820. Yet, because the end of the retaining bar extends into the channel 24, the corner blocks 10A, 10B benefit from the reinforcing action of the reinfocement material secured to the other blocks in the same course.
In addition to receiving the retaining bar 90 and reinforcement material 100, the channel 24 provides sufficient space to receive a lock flange 25 from a block in an upper course, as illustrated in
With reference to
As evident from
The size of the blocks 10A, 10B varies depending upon where the block is used, i.e. which course, in forming the corner. An example of the dimensions of a preferred block size are as follows: a length d1 of about 17.5 inches; a width d2 of about 9.0 inches; and a height d3 of about 7.5 inches. In addition, an example of the dimensions for a preferred channel 24 shape and location are as follows: a length d4 of about 14.5 inches; the closed end of the channel 24 being angled at an angle θ of about 5.0 degrees relative to vertical; a distance d5 of about 1.580 inches; a distance d6 of about 1.908 inches; a distance d7 of about 0.745 inches; a distance d8 of about 1.265 inches; a distance d9 of about 0.096 inches; a distance d10 of about 0.5 inches; a distance d11 of about 1.728 inches; a distance d12 of about 1.631 inches; a distance d13 of about 2.810 inches; radii r1 and r2 of about 0.5 inches; a radius r3 of about 2.115 inches; a radius r4 of about 0.5 inches; and a radius r5 of about 0.233 inches. These dimensions are exemplary only. Other dimensions for the blocks and channel are contemplated by and within the scope of the invention, depending upon the intended use of the blocks. The angle at the closed end of the channel 24 facilitates manufacturing by allowing the mold part that forms the channel 24 in the block to release easier.
Although capable of alternative construction, the blocks 10A, 10B are preferably formed of zero slump concrete. As is known in the art, the block material is commonly mixed in a batching plant in a high-speed process. Cement, aggregate, water, and possibly various admixtures are mixed in a hopper to form a concrete mixture which is placed into a mold box to form the blocks. To increase block output of this process and simplify the block forming process, typically a multiple block mold is used. In particular, the mold is configured to form a workpiece from which several blocks will be made. Once the workpiece is formed, the individual blocks are separated from the workpiece with a block splitter that splits through the workpiece. This splitting process also typically gives the exterior surfaces of the blocks a textured split-stone appearance.
As discussed above, the blocks 10A, 10B are preferably used together with the blocks, as well as the retaining bar and geosynthetic reinforcement material, described in U.S. patent application Ser. No. 09/487,820, to form a wall structure that has an exterior corner.
In order to adequately reinforce the wall structure adjacent the exterior corner, geosynthetic reinforcement material is preferably secured to the right-hand portion of the wall structure adjacent to the blocks that form the corner 52, with the reinforcement material extending back into the soil S. Further, geosynthetic reinforcement material is also preferably secured to the left-hand portion of the wall structure adjacent to the blocks that form the corner 52, with the reinforcement material extending back into the soil.
Prior to describing the preferred formation of the wall structure and exterior corner, the terminology that will be used to describe the wall structure will be explained. The right and left-hand portions of the wall structure 50 are preferably constructed from a plurality of blocks of the type disclosed in U.S. patent application Ser. No. 09/487,820. These blocks will be referred to hereinafter for convenience as “standard blocks” and are designated by numeral 60. Standard blocks are also designated “STD” in
The wall structure 50 also preferably includes starter or foundation blocks as described in U.S. patent application Ser. No. 09/487,820, which will be hereinafter referred to for convenience as “foundation blocks” and are designated by numeral 70. Foundation blocks are also designated “FDN” in
Further included are blocks that are referred to herein for convenience as “half high standard blocks” and are designated by numeral 80. Half high standard blocks are also referred to as “HALF HIGH UNIT” or “HALF HIGH”, and designated by “H”, in
The remainder of the blocks are preferably the blocks 10A, 10B, which will be hereinafter referred to as “right corner block” 10A (or similar) and “left corner block” 10B (or similar), respectively. The right and left corner blocks are also referred to as “CORNER UNIT”, and designated “CR” for a right corner block and “CL” for a left corner block, in
The construction of a preferred wall structure will now be described with reference to
Once the leveling pad is constructed, a plurality of the foundation blocks 70 are laid on the leveling pad to form the foundation of the right and left wall portions (see FIG. 5). In addition, a right corner block 10A having a length of, for example, about 14 inches and a foundation block 70 having a length of, for example, about 8 inches, are laid at the right corner. Further, a foundation block 70 having a length of, for example, about 5.0 inches is provided between the right corner block 10A and the remaining foundation blocks on the left-hand wall portion to complete what will be referred to as the foundation course CF (see FIGS. 5 and 9).
The wall structure 50 is formed from a plurality of courses C1, C2, . . . Cn. The construction of the standard blocks 60 is such that they occupy the entire height of each course. However, the blocks that form the exterior corner 52, i.e. the right and left corner blocks 10A and 10B and the half high standard blocks 80, are half the height of the standard blocks 60. Thus, for each course C1, C2, . . . Cn, the blocks at the exterior corner 52 are arranged into two subcourses SCn1 and SCn2 (see FIG. 9).
Referring to
As illustrated in
As
In the second course C2, the corner includes a subcourse SC21 that is formed by a left corner block 10B having a length of, for example, about 12.5 inches, and a half high standard block 80 having a length of, for example, about 3.5 inches. The corner also includes a subcourse SC22 that is formed by a right corner block 10A having a length of, for example, about 12.0 inches, and a half high standard block 80 having a length of, for example, about 3 inches (see
When the second course C2 is complete, the channel in the right corner block 10A of subcourse SC22 is aligned with the channels in the standard blocks 60 as illustrated in
The remaining courses of the wall are constructed in similar fashion to the first two courses C1 and C2, with first and second subcourses SCn1 and SCn2 forming the exterior corner and standard blocks completing each course. The blocks and exemplary block sizes that are used to form the corners of seven additional courses is schematically set forth in
For each course, the lock flange(s) 25 of a standard block or half high standard block of an upper course will extend into the channel 24 of the corner blocks 10A, 10B above the retaining bar 90 that is disposed in the channel to help retain the retaining bar and reinforcing material 100 within the channel 24 (see FIGS. 10 and 11). As shown in
When the blocks and exemplary block sizes set forth in
As seen in
The right-side and left-side wall portions have been illustrated as being generally linear. However, the standard blocks 60 can be constructed to permit the construction of curved wall portions that are provided with an exterior corner as described herein. As will be appreciated by those having skill in the art, when a curved wall portion is constructed, the retaining bar will likewise need to be curved if reinforcing material is to be extended from the blocks of the curved wall portions.
While preferred embodiments of the invention have been disclosed in detail in the foregoing description and drawings, it will be understood by those skilled in the art that variations and modifications thereof can be made without departing from the spirit and scope of the invention which resides in the claims hereinafter appended.
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| Number | Date | Country | |
|---|---|---|---|
| 20030150184 A1 | Aug 2003 | US |
