MECHANICALLY STABILIZED EARTH (MSE) RETAINING WALL EMPLOYING GEOSYNTHETIC STRIP WITH PLASTIC PIPE(S) AROUND STEEL ROD
Disclosed are various embodiments of a mechanically stabilized earth (MSE) retaining wall that employ, for reinforcement, a geosynthetic strip that attaches to the MSE retaining wall and extends into the backfill soil. In one embodiment, the MSE retaining wall has at least one concrete panel. The panel has a cavity extending from the backside into the body for receiving a flexible, generally flat, geosynthetic strip. The panel has a plastic pipe (or first cylindrical body) that is situated within the body of the panel in a position so that the plastic pipe is generally horizontal from a front elevation view vantage point of the panel and is generally parallel with the backside of the panel from a top view vantage point of the panel. The plastic pipe extends through the cavity and its ends reside within the concrete panel. The MSE retaining wall further includes a steel rod situated inside of the plastic pipe. The geosynthetic strip extends from backfill soil adjacent to the backside of the panel, into the cavity of the panel, around the elongated body of the plastic pipe, out of the cavity, and into the backfill soil. In another embodiment of the MSE retaining wall, an end of the geosynthetic strip is bound to the panel with a double compression loop arrangement that utilizes an additional solid second plastic rod (or second cylindrical body).
CLAIM OF PRIORTY
The present application claims priority to and the benefit of provisional application Ser. No. 63/135,086, filed Jan. 8, 2021, which is incorporated herein by reference in its entirety.
RELATED APPLICATIONSThis application is related to pending application no. xx/xxx, xxx, filed on even date herewith, titled “MECHANICALLY STABILIZED EARTH (MSE) RETAINING WALL EMPLOYING ROUND RODS WITH SPACED PULLOUT INHIBITING STRUCTURES,” with attorney docket no. 51813-1220, by the same inventor herein, which is incorporated by reference in its entirety.
FIELD OF THE INVENTIONThe present invention generally relates to modular earth retaining walls, and more particularly, to mechanically stabilized earth (MSE) retaining walls.
BACKGROUND OF THE INVENTIONModular earth retaining walls with concrete panels are commonly used for architectural and site development applications. Such walls are subjected to very high pressures exerted by lateral movements of the soil, temperature and shrinkage effects, and seismic loads.
In many commercial applications, for example, along or supporting highways, etc., each concrete panel can weigh between two and five thousand pounds and have a front elevational size of about eight feet in width by about five feet, four inches in height.
Oftentimes, the earth retaining walls of this type are reinforced. More specifically, a conventional mechanically stabilized earth (MSE) retaining wall with steel reinforcement is typically reinforced with steel strips or welded wire meshes that extends backward, or perpendicular, from the rear of a concrete panel to reinforce the backfill soil.
SUMMARY OF THE INVENTIONThe present disclosure provides various embodiments of a mechanically stabilized earth (MSE) retaining wall that employ, for reinforcement, a geosynthetic strip that attaches to the MSE retaining wall and extends into the backfill soil.
One embodiment of the MSE retaining wall of the present disclosures, among others, can be generally summarized as follows. This embodiment enables a geosynthetic strip loop to be adequately secured to a panel. The MSE retaining wall has at least one concrete panel, the panel having a generally planar body with a frontside, a backside, and a surrounding peripheral edge. The panel has a cavity extending from the backside into the body for receiving the geosynthetic strip. The panel has a plastic pipe having an elongated body extending between first and second ends. The plastic pipe is situated within the body of the panel in a position so that the elongated body of the pipe is generally horizontal from a front elevation view vantage point of the panel and is generally parallel with the backside of the panel from a top view vantage point of the panel. The elongated body extends through the cavity. The first and second ends reside within the concrete panel. The MSE retaining wall further includes a steel rod having an elongated body extending between first and second ends. The rod is situated inside of the pipe. A flexible, generally flat, geosynthetic strip extends from backfill soil adjacent to the backside of the panel, into the cavity of the panel, around the elongated body of the plastic pipe, out of the cavity, and into the backfill soil.
Another embodiment of the MSE retaining wall of the present disclosure, among others, can be summarized as follows. 12. This embodiment enables a single geosynthetic end of a geosynthetic strip to be adequately secured to a panel. The MSE retaining wall has at least one concrete panel, the panel having a generally planar body with a frontside, a backside, and a surrounding peripheral edge. The panel has a cavity extending from the backside into the body. A first cylindrical body, or first plastic pipe, has an elongated body extending between first and second ends. The first plastic pipe is situated within the body of the panel in a position so that the elongated body of the pipe is generally horizontal from a front elevation vantage point of the panel and is generally parallel with the backside of the panel from a top view vantage point of the panel. The elongated body extends through the cavity. The first and second ends reside within the concrete panel. A steel rod having an elongated body extends between first and second ends. The rod is situated inside of the pipe.
A second cylindrical body, which can be for example, a solid plastic pipe, has an elongated body extending between first and second ends. The second cylindrical body is situated within the cavity of the panel in a position so that the elongated body of the second cylindrical body is generally horizontal from the front elevation vantage point of the panel and is generally parallel with the backside of the panel as well as the first plastic pipe from the top view vantage point of the panel. A flexible, generally flat, geosynthetic strip extends from backfill soil adjacent to the backside of the panel. The strip extends into the cavity past the underside of second cylindrical body, then clockwise around the first cylindrical body, then clockwise around second cylindrical body, then counterclockwise around the first cylindrical body thereby being bound under a part of the strip already around the first plastic pipe, and then past the underside of second cylindrical body thereby being bound under a part of the strip already around second cylindrical body.
Other embodiments, apparatus, systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
An innovative soil reinforcement rod has been recently invented by the inventor for the earth retaining wall market. The new reinforcement rod 1 uses a new geometry of reinforcement, shown in
One of the main hinderances of using steel as reinforcement in backfill soils 15 is the anticipated degradation of the actual steel, or steel loss due to corrosion. A flat bar 4 has the degradation across the entire exposed surface area making a rectangular shape not as efficient as a round shape. The surface area of steel is less when comparing a round bar to a flat bar. For instance, a ½ inch round solid bar has 0.2 square inch area and an exposed surface area of 1.57 inches. A comparable rectangular shape that is 1 inch by 2/10 inch has the same steel cross section area of 0.2 square inches but an exposed surface area of 2.4 inches. That equates to the round bar having 1.57/2.40, or 65 percent (%), of the exposed surface area when compared to a conventional rectangular shape. As mentioned previously, retaining wall contractors have also used welded wire mesh of round bars 6 as reinforcement to provide passive pressure by the perpendicular bars 7 to resist pullout or provide reinforcement. The round bars use steel more efficiently as described above but are not very efficient or effective with respect to pullout because of the round shape of the steel perpendicular to the direction of stress 7 being pulled through the soil 15 which does not create as much resistance and passive pressure because the soil 15 tends to move around the rounded edges 8. Using the earth reinforcement rod 1, the passive earth anchoring is created by the flat disks 3 being pulled through the soil 15.
Research and extensive testing by the inventor have been used to realize and confirm the optimum size 9 of disk 3 and spacing 10 along the solid bar length. Testing was performed by running numerous pullout tests in a standard pullout box containing soil by a reputable industry testing laboratory that specializes in testing and evaluating earth reinforcement materials. The results were compared together, as illustrated in
With reference to
In some embodiments, the reinforcement rod 1 can be employed without the ridges 11 so that the outer surface of the bar 5 is uniformly round. . The raised ridges on the rebar rod help resist pullout of the tensile steel rod through the soil. However, the passive resistant disks provide the majority of the pullout resistance. Therefore, a smooth steel bar with no raised ridges but with the disks could be used as well, providing a big increase in pullout resistance. The small ridges are a benefit but not required to achieve substantial increase in pullout resistance in reinforced soil applications due to the disks attached to the rod.
It should also be noted that the pullout inhibiting structures can be implemented with different peripheral shapes (other than circular), for example, square, polygonal, etc. Furthermore, the structure does not necessarily need to be planar, just have a surface region that runs transverse, or at an angle (e.g., ninety degrees, etc.), to the elongated body of the rod 1.
MSE ConnectionThe recent invention of the new earth reinforcement rod 1 has the challenge of how to connect the steel reinforcement rod 1 to the back of the concrete panel face 14 of
The objective of reinforcement connection to the back of a concrete panel 14 for all MSE (mechanically stabilized earth) retaining wall systems is to get the highest strength possible in the connection and as close to the full capacity of the reinforcement, as possible. An anti-shear collar 19, as shown in
The earth reinforcement rod 1 can be connected to the connector loop 17 in ways other than as previously described in connection with the preferred embodiment with the flange nut 18 in combination with the anti-shear collar 19. For example, a threaded insert cast into the rear of the concrete panel to allow a threaded rod end of the rod 1 to be screwed in the back of the panel creating a connection of the round rod to the concrete panel.
As another example embodiment, a double loop of steel rod extending out the back of the concrete panel can be cast into the rear of the concrete panel, which allows a reinforcement rod 1 with a welded perpendicular piece of rod forming a “T” shape to be inserted into and behind the double loop, thereby connecting the reinforcement rod 1 to the back of the panel.
As another example embodiment, the rod 1, in a straight or bent configuration, can be welded to the connector loop 17.
As another example embodiment, the rod 1, in bent and threaded configuration, can be attached to the connector loop 17 using two opposing flange nuts 18 on opposing sides of the connector loop 17 (i.e., in a sandwich-like configuration).
As another example embodiment, the rod 1, in the bent and threaded configuration, could be provided with a metal stop or barrier of some sort that is welded to or otherwise attached to the rod 1 in or near the threads. The flange nut 18 can then be used to bind and secure the connector loop 17 along the rod 1 against the stop or barrier.
Top of Panel Geometry/Illimination of Separate Coping UnitIn an attempt to not require a conventional coping unit, unsightly joints, and exposed lifting inserts, the present disclosure provides a better top of wall condition, as shown in
Most, if not all, of the current MSE retaining wall suppliers on the market use a similar separate coping unit 23 shown in
The top panel 14 of the present disclosure removes not only the unsightly lap or tongue and groove joint at the top or uneven surface, but also eliminates the lifting inserts. As shown in the prior art wall embodiment of
Again, the inventor realized that there was a way to provide a clear and precise rectangular finished top that both pleases aesthetically, but also serves the function of topping out the retaining wall. Also, the top panel cast produces the concrete panels 14 at the exact slope geometry 27 to follow roadway grade behind the wall. In order to remove the required lifting inserts from the top side of the panel 24, a specialized lifting tool 28 shown in
The lifting tool 28 allows the concrete panel 14 to be hoisted and held vertical, but also avoids the unsightly lifting inserts 24 (
Steel reinforcement is not preferred or allowed when using high resistivity backfill soils 15 or high corrosion environments that exist on project sites, like near the saltwater coast or roadways that have de-icing salt spread during winter. Geosynthetic reinforcement using geosynthetic strips 32 is preferred and used to create the MSE retaining wall 2, as illustrated in
All of the foregoing prior art embodiments of a geosynthetic loop connection in
With reference to
The MSE geosynthetic loop connection of the present disclosure provides an economical and easy method to produce the concrete panel 14 with a mechanism for installing the geosynthetic strip 32 in the field. The geosynthetic strip 32 can be any suitable material, but is typically and preferably a polyester that is encased in high-density polyethylene (HDPE). A typical width of the strip 32 is 2 inches. This MSE geosynthetic loop connection is a particular and unique combination of a PVC pipe 33 for protection of the steel (readily available and inexpensive), and a rubber insert to create a void (rubber can be cast to various configurations so the ideal geosynthetic strip wrap geometry can be achieved). A common concrete rebar 34 is placed inside the PVC pipe 33 during the concrete panel casting that provides the strength of the connection. The rebar extends well beyond the ends of the PVC pipe 33. All three components, when used in this configuration and method was the result of numerous trial connections, research, and tensile testing to find the best performing and economical process to connect the geosynthetic strip to the back of a concrete panel 14.
Going a step further, sometimes, an MSE geosynthetic strip loop cannot be achieved in the field, and a single geosynthetic strip end must be secured to the back of a concrete panel 14. Many methods have been presented in the industry using separate clamps and fasteners. However, tools needed to complete the connection with fasteners or clamps can be cumbersome in the field and technically difficult to verify by the inspector that the connection is complete. Looking for a simple-to-install, single strip connection mechanism that is easy to inspect is a big challenge. After much research, trials, and evaluation using full scale tensile tests by the inventor, a unique, effective, economical, and inspectable connection was realized.
As shown in
Testing confirmed that 100% of the geosynthetic strip could be achieved with this connection. Also, the free end 36 of the geosynthetic strip 32 exposed assured enough geosynthetic strip 32 was in the connection allowing inspectors to quickly observe the connection was complete.
Finally, many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.
Claims
1. A mechanically stabilized earth (MSE) retaining wall, comprising:
- at least one concrete panel, the panel having a generally planar body with a frontside, a backside, and a surrounding peripheral edge, the panel having a cavity extending from the backside into the body;
- a plastic pipe having an elongated body extending between first and second ends, the plastic pipe situated within the body of the panel in a position so that the elongated body of the pipe is generally horizontal from a front elevation view vantage point of the panel and is generally parallel with the backside of the panel from a top view vantage point of the panel, the elongated body extending through the cavity, the first and second ends residing within the concrete panel;
- a steel rod having an elongated body extending between first and second ends, the rod situated inside of the pipe;
- a flexible, generally flat, geosynthetic strip extending from backfill soil adjacent to the backside of the panel, into the cavity of the panel, around the elongated body of the plastic pipe, out of the cavity, and into the backfill soil.
2. The wall of claim 1, wherein the steel rod is rebar.
3. The wall of claim 1, wherein the plastic pipe made of PVC.
4. The wall of claim 1, further comprising a plurality of the concrete panels, the plurality including the at least one concrete panel.
5. The wall of claim 1, wherein an end associated with the cavity in the panel is U-shaped from a side view vantage point of the panel, in order to permit easy passage of the geosynthetic strip around the plastic pipe during installation of the geosynthetic strip.
6. The wall of claim 1, further comprising a cylindrical body having an elongated body extending between first and second ends, the second cylindrical body situated within the cavity of the panel in a position so that the elongated body of the cylindrical body is generally horizontal from the front elevation vantage point of the panel and is generally parallel with the backside of the panel as well as the plastic pipe from the top view vantage point of the panel, and wherein the geosynthetic strip extends past the underside of the cylindrical body prior to extending around the elongated body of the plastic pipe, and wherein the strip extends, prior to extending out of the cavity, clockwise around the cylindrical body, then counterclockwise around the plastic pipe thereby being bound under a part of the strip already around the plastic pipe, and then past the underside of the cylindrical body thereby being bound under a part of the strip already around the cylindrical body.
7. A mechanically stabilized earth (MSE) retaining wall, comprising:
- at least one concrete panel, the panel having a generally planar body with a frontside, a backside, and a surrounding peripheral edge, the panel having a cavity extending from the backside into the body;
- a first cylindrical body, the first cylindrical body being a first plastic pipe, the first plastic pipe having an elongated body extending between first and second ends, the pipe situated with the body of the panel in a position so that the elongated body of the pipe is generally horizontal from a front elevation vantage point of the panel and is generally parallel with the backside of the panel from a top view vantage point of the panel, the elongated body extending through the cavity, the first and second ends residing within the concrete panel;
- a steel rod having an elongated body extending between first and second ends, the rod situated inside of the pipe; a second cylindrical body having an elongated body extending between first and second ends, the second cylindrical body situated within the cavity of the panel in a position so that the elongated body of the second cylindrical body is generally horizontal from the front elevation vantage point of the panel and is generally parallel with the backside of the panel as well as the first cylindrical body from the top view vantage point of the panel; and a flexible, generally flat, geosynthetic strip extending from backfill soil adjacent to the backside of the panel, the strip extending into the cavity past the underside of second cylindrical body, then clockwise around the first cylindrical body, then clockwise around second cylindrical body, then counterclockwise around the first cylindrical body thereby being bound under a part of the strip already around the first cylindrical body, and then past the underside of second cylindrical body thereby being bound under a part of the strip already around second cylindrical body.
8. The wall of claim 7, wherein the steel rod is rebar.
9. The wall of claim 7, wherein the plastic pipe made of PVC.
10. The wall of claim 7, further comprising a plurality of the concrete panels, the plurality including the at least one concrete panel.
11. The wall of claim 7, wherein an end associated with the cavity in the panel is U-shaped from a side view vantage point of the panel, in order to permit easy passage of the strip around the plastic pipe during installation of the strip.
12. The wall of claim 7, wherein the second cylindrical body is a solid plastic rod without a throughway.
Type: Application
Filed: Jul 20, 2021
Publication Date: Jul 14, 2022
Inventors: Thomas Leonard Rainey (Marietta, GA), Joseph Wilcox Rainey (Melbourne, FL)
Application Number: 17/380,707