Plastic Panel Erosion Barrier

This invention is a structural ground retaining construction adaptable to use for seawalls, ground erosion barriers and the like incorporating a relatively narrow, light weight extrusion molded structural plastic panel or panel strip having a cross sectional configuration which allows construction of walls in either of two different cross sectional shapes and structural strengths.

The panel strip has a stretched generally broad Z-shaped cross section with opposite male and female interlockable edges for establishing an interlocking association with adjacent similar panels in a wall construction.

Seawalls and like erosion protection walls in the past have usually been made of steel to stand against high waves in the order of 30 feet or more at ocean or large lake shorelines. To utilize such heavy protection in the many hundreds of thousands of miles of shoreline of inland lakes, rivers and streams however is much beyond practical needs and would be exorbitant both in cost of material as well as labor and equipment required for construction and installation of such walls. Accordingly there is considerable, if not extreme, need for a low cost and more readily installable type erosion protection wall within the range of installation by the numerous small business and individual land owners on lakes and rivers who are confronted with erosion problems. Many can only afford small close-to-home construction contractors or do-it-yourself type installations not involving the cost of heavy equipment such as heavy pile drivers and automatic impact hammers and vibrators, let alone the equipment required to lift and handle heavy panels of steel or other metal wall constructions.

It is known in the art to make seawall constructions of corrugated plastic panel strips with interlocking edges which lend themselves to formation of walls of commercially available relatively thin undulating cross section such as are disclosed in U.S. Pat. Nos. 4,674,921 and 4,690,588. Such a system of corrugated panels has limited section modulus or bulk modulus in assembly with various soil and ground conditions with which it is associated. That is, barrier walls of such corrugated panels are relatively thin in depth and provide no selectible accommodation to the needs of special ground conditions requiring strength in the panel construction but relies more heavily if not almost entirely upon anchoring techniques for wall strength.

The invention herein disclosed is a plastic panel strip of stretched Z-shaped cross sectional design with opposed male and female interlock edges for mating association with adjacent panel strips. The panel strip design incorporates a "V" configuration on opposite faces which allows optional interlocked alignment to provide a wall having either a secondary deep V-shaped cross section or a box ribbed cross sectional shape formed of pairs of adjacent panel strips. The panel shape and edge interlock design permits top to top alignment of adjacent panels for the deep V-shaped cross section or alternate top to bottom turnover of adjacent panel strips to provide the thicker box ribbed cross sectional shape to the wall. The deep "V" wall shape made of the panel strip has less depth and less section modulus than the box ribbed construction, but provides greater breadth of coverage for a given number of panels than is provided by the box rib construction. In other words for a given length of wall made with the panel strips more panel strips are required with the box rib construction than with the deep "V" construction.

The top to bottom reversal of the alternate panels of the box rib construction is made possible because of the interlock shape in which the male portion extends outwardly at the edge of the panel in symmetrical form on opposite sides of the edge of the wall while similarly the mating female portion, which is larger to accommodate the male interlock edge, also extends outwardly and symmetrically on both sides of the edge of the wall. This forms a partial circle at the female edge portion within which the male portion of an adjacent strip can be interlocked during installation of a bulkhead wall by insertion of the bottom of the panel therein and then sliding the panel edge downwardly in nested relation within the female portion until force is necessary to push the panel into the ground, frequently under water, in which it is embedded in place.

The cross sectional shape of the panel strip is described as a stretched Z-shaped cross section, in that the side sections extending from opposite sides of the central body section extend from the body with an obtuse angle therebetween, in other words with an angle therebetween greater than 90 degrees. The side sections extending in opposite directions from the central body section extend in directions generally parallel to each other but with an oppositely facing obtuse angle therebetween. In practice the angle between the body and the leg portions is found to be preferably in the order of 120 degrees.

The panel strips because of their shape, individually have a section modulus of fair magnitude across their length, but in assembly with adjacent panel strips have a greater stiffness and section modulus as hereinafter explained. Although, relatively rigid to bending across their length they can be made of thickness providing a degree of springiness which allows a desirable slight degree of lateral flex without reaching a yield strength or appreciably affecting structural properties, thereby facilitating formation of bends in barrier walls formed of the panel strips.

It is an object of the invention to provide a light weight, easy to handle plastic panel strip adaptable to making a ground erosion barrier for seawalls and the like which will withstand soil shifts, weather changes and wave action.

Another object of the invention is to provide a plastic panel strip designed with edge interlocks which permit alternate inversion of panel strips to selectably form wall constructions of different cross sectional shapes and strength with the single shaped panel strip.

Still another object of the invention is to provide a panel strip system of assembly into an erosion resistant wall in which the panel strips can be interlocked to any of a wide range of angular linear orientations including right angular turns without need for specially shaped additional strips or connecting sections.

A feature of the invention is the ease with which the plastic panel in strip widths can be handled because of their relatively light weight.

Another feature of the invention is its ability of the panel strips in multiple assembly to provide bends and corners in wall constructions without need for special fittings, corner adapters or panel strips of different shape.

Still another feature of the invention is the slight lateral bendability or capability of the panel strips to be flexed laterally across their width to further assist in enabling the assembly of panel strips into a barrier capable of meeting a wide range of linear contours to match the numerous irregularities confronted in building, ground and shore line barrier constructions.

Other objects and features which are characteristic of the invention are set forth with particularity in the appended claims. The invention, however, both in organization and construction, together with further objects and features thereof may be best understood by reference to the following description taken in connection with the accompanying drawings.

FIG. 1 shows two panel strips of the invention in side-by-side interlocked relation illustrating a cross section having a deep "V" wall configuration;

FIG. 1A is a schematic illustration showing in top profile the assembly of a series of four panel strips in a deep "V" wall configuration with a whaler such as a wooden or plastic bar extending along one side;

FIG. 2 shows two side-by-side interlocked panel strips of the invention with one upside down relative to the next illustrating a cross sectional shape of box rib construction;

FIG. 2A is a schematic illustration showing in top profile the assembly of a series of four panel strips in a box ribbed wall configuration with a whaler extending along the wall in secured relation to one side thereof;

FIG. 3 illustrates an assemblage of panel strips of the invention forming a seawall with a deep "V" cross sectional shape as in FIG. 1 with a concrete cap at the top and a tie rod connection to an embedded anchor;

FIG. 4 illustrates the arrangement of a deep "V" profile wall made of the panel strips of the present invention showing how a box rib corner can provide a 90 degree turn in the wall;

FIG. 5 is another illustration of a deep "V" wall construction similar to that shown in FIG. 3 illustrating how the panel extends down in anchored relation below the water level of the shoreline on which it is constructed; and

FIG. 6 is an illustration of a seawall having a box rib cross sectional shape for a deeper seawall having a whaler and additional tie rods for greater strength and resistance to erosion.

Referring to the drawings in greater detail, FIG. 1 illustrates an assemblage of panel strips 9 assembled in interlocked relation to form a deep "V" wall configuration wherein the central body section 11 or central web of the strip has two side sections or extensions 12 and 13. The side section 12 connected to the body section 11 provides a male interlocking edge 14, a somewhat semi-circular configuration having a short extension 14a on one side of section 12 and a short extension 14b on the other side of section 12. Similarly the side section 13 at the opposite edge of the panel strip parallel to the side section 12 has a female interlocking portion 15 extending along its edge also symmetrically arranged with an extension 15a on one side of the side section 13 and extension 15b on the other side forming the housing or nest for the female interlock 15 within which the male portion 14 can slide from top to bottom to from the interlocked relation between the two panels. The angle between the body section 11 and the side sections 12 and 13 respectively, is in an obtuse angle range of 90 degrees to less than 180 degrees, but preferably is in the order of 120 degrees as illustrated. To avoid stress creating point contacts by whalers, the outermost corners of the panels 18 and 19 are flat shaped regions from top to the bottom of the strip thereby establishing a flat solid area for contact of the panel strips by the strength imparting whalers 26 extending across the outside of a wall as shown schematically in FIG. 1A.

FIG. 2 illustrates the same panel strip 9 as shown in FIG. 1 assembled with an adjacent like panel 9 inverted so that the top and bottom are interchanged in their interlocked association thereby forming a box rib wall configuration. As will be seen in the right side panel strip 9 the interlock, extensions 15a and 15b are interchanged relative to the position of the similar extensions of the female interlock 15 in the left hand strip. Likewise the male portions 14a and 14b in the right side panel strip 9 are interchanged relative to the similar portions 14a and 14b in the left side panel strip 9. The flattened corners or shoulders 18 and 19 and the right side panel strip are also inverted relative to the shoulders 18 and 19 in the left side strip.

As shown schematically in FIG. 2A, the slight lateral flexibility of the individual strips permit the box ribbed configuration to give slightly at the region of the interlock 15 of interconnected panels when a whaler 26 is extended in secured relation across one side. The slight flex further bends the flattened corner of each strip toward a more flush facing relation with the whaler thereby reducing the tendency toward excessive stress producing point contacts.

The plastic panel strips of the invention are preferably made of a vinyl resin such as that sold by B. F. Goodrich Corporation under the name "GEON", a trademark of B. F. Goodrich. Such resin has been found to be strong and highly weatherable and of properties well adapted to providing coastline protection.

When such panels are assembled in a deep "V" wall construction as illustrated in FIG. 1, it has been determined, by way of example, to have a relative stress to strain section modulus or stiffness index of 1.479 compared to 5.005 for the box ribbed wall assembly of the same panel strips because of the differences in the geometrical designs. Variables, among others, which dictate whether one or the other of such wall constructions is utilized are soil conditions, loads, and wave and weathering action. For heavier loads, or uncertain conditions, the box ribbed design is preferable.

By way of example without intention to be limiting, in an actual construction of panels according to this invention panel strips have been made having a dimension across the top of the configuration in the order of 12". With the deep "V" design and 120 degree angle at the corners 16 and 17, two panels assembled in interlocked relation next to each other as in FIG. 1 will provide a 24" width coverage. The thickness of the deep "V" wall construction is then in the order of 3" whereas the cross section of a box rib design made of the same such panel strips will have a 6" depth and a 21" width coverage, 121/2% less than the "V" configuration wall.

FIG. 3 shows a deep "V" configurated wall 30 having an outer corner 37a and inner corner 37b made of the same panel strips. The seawall is provided with a poured concrete cap 31 into which the top edge of the wall is embedded. Although wood or resin type whalers might be used to hold the top edge of the wall, the poured concrete cap is preferred to provide a holding of each incremental segment of the top of the wall thereby distributing the holding force and minimizing possible stress imparting point contacts.

An adjacent concrete strip 39 is shown extending adjacent and along the length of the cap 31 both to provide a means of mobility along the length of the wall as well as to hold adjacent ground portions in place in the event of wave action over the wall. Gravel such as pea stone gravel which will assist in providing drainage downwardly and to effect distribution of ground stresses is filled in behind the wall 30. The ground 38 extends in an upward inclination in usual form along the seawall and the concrete anchor 32 is provided a distance back from the seawall extending along its length and embedded below the level of ground 38. A tie rod 33 assists in holding the wall in place by being connected to a reinforcing rod embedded in the cement cap 31 when it is formed and extending back to a similarly embedded reinforcing rod 25 embedded in the concrete anchor 32. The tie rod can be connected between the two reinforcing rods 24 and 25 by merely bending the ends about the rods as illustrated in FIG. 3.

The female interlock which in cross section is "C" shaped with the gap or opening between the ends of the "C" being sufficiently wide to accommodate the wall thickness of an adjacent interlocked panel strip. The gap is enough opening to permit a bending alignment of an adjacent panel without flexing the panels but small enough that the male portion is retained and prevented from slipping out from the female gap opening. In other words adjacent panels are provided a degree of bend in their interlocked association to accommodate some incongruities in ground profile contours. For example a gap in the female interlock allowing an adjacent panel bend in a range up to 121/2 degrees in either direction from a straight line association has been found desirable. Such a range of bending adjacent panel strips proves advantageous both in assisting matching of ground incongruities as well as in allowing turns, including 90 degree turns with a series of adjacent selectively inverted side-by-side panels in box ribbed as well as in deep "V" shaped wall assemblies. The additional slight lateral flex or bend possible within each strip itself further assists in permitting formation of wall adjustments to needed nonstraight alignments and bends in a wall assembly.

FIG. 4 illustrates more clearly how a deep "V" wall made of the panel strips 9 can be assembled to provide a 90 degree angle or corner such as at an outside corner 37a or an inside corner 37b in FIG. 3. In this regard the deep "V" wall is ended and a corner is formed by inverting an adjacent panel 9 which results in providing a turn. Where the wall turn thus provided is not completely 90 degrees the amount of bending in alignment allowed at the joint allows progressive incremental bending at interlocking joints to form the 90 degrees turn or slight variation therefrom desired. After the first inversion of an adjacent panel strip 9 the remaining panel strips 9 are maintained in their upright fashion so that a continuance of the deep "V" wall construction is provided after only one inversion of a panel strip 9.

The above points out another aspect of the invention in that as desired a continuous wall might be alternately made with the sawtooth deep "V" configuration or the box ribbed configuration, depending on needs for strength and nonstraight alignments in shorelines. The assembly of a box ribbed wall differs from assembly of the deep "V" wall construction only in that in the box rib arrangement alternate panel strips are inverted top to bottom to produce the box ribbed effect.

FIG. 5 shows a seawall 30 of deep "V" configuration with interlocking edges 35 and a poured concrete cap 31 adjacent a body of water 39. In this arrangement the concrete anchor 32 embedded in the ground 38 has a tie rod 33 extending thereto from the concrete cap 31 in which a reinforcing rod 24 running the length of the cap provides an anchor for the tie rod 33 which has its end 36 bent and clamped around the reinforcing rod 24. Similarly the other end of the tie rod 33 has its end 34 bent and clamped about a reinforced rod 25 running the length of the concrete anchor 32 as well.

FIG. 6 shows how a seawall of greater height than shown in FIG. 5 for a deeper water shoreline can be provided by provision of additional lower level tie rods 53. The wall 40 of ribbed construction with adjacent strips interlocked at joints 45 provide greater strength than the deep "V" wall. Correspondingly a poured concrete cap 41 in which the assembled panel top is embedded is sufficiently wide to accommodate the greater width of the box rib construction. The tie rods 43 extend between a reinforcing rod in the cap 41 about which they are bent and clamped at ends 46 while the opposite 44 of the tie rods 43 are clamped about a reinforcing rod 42 running the length of the concrete anchor 42 embedded below the level of the ground 48. Additional tie rods 53 are provided below the level of the tie rods connected to the cap 41 to impart greater strength to the deeper wall 40. The wall 40 extends down below the ground level under water. It is anchored there to a depth necessary to provide the bottom support for the wall. Where the tie rods 53 extend to ends 54 they are bent and clamped about a reinforcing rod 50 extending along the length of the concrete anchor while the opposite ends are threaded and secured by nuts 57. The tie rods at the water's edge extend through a whaler 58 which runs the length of the wall while the tie rods 53 are provided at space distances along the length of the wall depending upon the strength to be imparted and required to hold the whaler 58 in place.

As pointed out, because of the light weight of the panels in formation of such a wall the euipment necessary to pound them into the soil under water can be relatively simple tool mechanisms such as pneumatic hammers, comparatively light weight automatic hammers which can pound the top of the panels with pounding caps mounted thereon or ground disrupting water jets extending downwardly from longitudinal tubes on opposite sides of the base of each panel during installation to make way for the panel.

In view of the foregoing it will be understood that many variations of the arrangement of our invention can be provided within the broad scope of the principles embodied therein. Thus, while particular preferred embodiments of our invention have been herein shown and described, it is intended by the appended claims to cover all such modifications which fall within the true spirit and scope of the invention.