Patent Publication Number: US-2006010819-A1

Title: Retaining wall with plastic coated wooden panels

Description:
CROSS REFERENCE  
      This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/891,930, filed Jul. 15, 2004 in the U.S. Patent and Trademark Office. 
    
    
     FIELD OF THE INVENTION  
      This invention concerns retaining walls of the type used for retaining the earth at the water&#39;s edge of a body of water, particularly where the wall is to be exposed to harsh environmental conditions, such as extreme heat and cold, moisture, insects, abrasion, etc.  
     BACKGROUND OF THE INVENTION  
      Barrier walls can be formed of a plurality of elongated vertically oriented piles having their lower extremities driven into the earth to a depth sufficient to support the piles and their associated structural elements. Horizontally extending wales are mounted to the piles, and vertically oriented structural panels are partially driven into the earth adjacent the wales. Usually, the panels have interlocking male and female opposed edges that are used to connect to the edges of the panels together. Also, the male and female edges of the panels are used for guiding the next panel into position in the wall structure by engaging the male and female edges of the adjacent panels as the oncoming panel is driven into the earth. This causes the connected panels to form a continuous barrier wall.  
      Because of the strength required for the panels when being driven into the earth and the strength required under the load conditions, the panels have to be strong. In the past, panels have been made of wood, and the wood can be cut to specific sizes for providing proper strength characteristics to the wall structure. However, wooden panels are subject to deterioration from marine borers and other insects, and rot and deterioration from impact by other objects. In order to avoid deterioration from rot and marine borers, wooden panels can be chemically treated. This slows the deterioration process of the panels from marine borers but provides the potential hazard of leaching of hazardous chemicals from the panels into the water and adjacent surroundings, possibly causing an environmental hazard. Also, wooden panels tend to shrink and/or swell in response to their environmental conditions. This tends to cause gaps between the panels in the wall structure, allowing water, silt and other undesirable elements to pass with water through the wall structure. In order to avoid the passage of material through the panels, wooden panels have been formed with tongue and groove edges that mate together in an attempt to reduce the ease of passage of the materials between adjacent panels. Another preventive measure is to use additional sheet material that is spread across the panels so as to retard movement of particles through the gaps between panels.  
      More recently, retaining walls have been formed with metal panels, such as steel or aluminum that are stronger than wood. The metal panels have been formed in cross sectional shapes such as V-shapes, Z-shapes, etc. that provide lateral strength and stability to the panels. This enables the thicknesses of the panels to be reduced substantially so as to conserve on the weight and expense in forming and handling the panels. However, the shaped panels are sometimes considered undesirable because they do not present a flat surface that is more visually and structurally pleasing.  
      At the present time, the most popular panels for the construction of retaining walls are extruded plastic panels. The panels formed of plastic have good compression strength properties so that they can be driven into the earth, but their lateral strength properties are weaker than the metal panels. In order to provide lateral strength to the panels, the V-shaped and Z-shaped profiles of the panels have been increased and the thickness of the panels has been increased.  
      While the metal and plastic panels have been successful in avoiding deterioration by marine borers and other insects, the profiles of the panels are still objected to by many since they do not provide a pleasing, less industrial look like the flat panels.  
      Recently, structural panels have been formed of wooden boards with plastic surfaces that form envelopes about the boards and protect the interior wood from marine borers, abrasion, moisture, etc. In some instances, the plastic material has been applied by spraying it onto the surface of wooden boards, as shown by U.S. Pat. No. 6,135,675, or by vacuum extrusion of plastic material onto the surface of the wooden boards, as disclosed in co-pending U.S. patent application Ser. No. 10/891,930. By providing the protective plastic surfaces to the wooden boards, there has been a beneficial result of reduction in deterioration of the panels from marine borers, better moisture control of the interior wooden boards of the panels, and reduced deterioration from impact, abrasion, and other external sources.  
      However, the known panels made of wooden boards with plastic exteriors have not been successful in forming panels that are connected edge-to-edge to form a strong and continuous barrier that retards the movement of water and water-borne particles through the wall structure. U.S. Pat. No. 5,360,295 discloses the use of plastic tongue and groove edge attachments that are mechanically attached to the opposed edges of wooden boards, requiring attachments to both edges of the boards. This requires the manufacture of the two plastic edge attachments and the additional separate functions of attaching both of the edge attachments to the boards. Also, the tongues and grooves are formed with voids between the wood and the plastic material that forms the tongues and grooves, thereby forming spaces that can receive and hold water. The retention of water between the boards and their tongues at one edge of the panels and/or between the boards and their grooves at the other edge of the panels introduces the hazard of freezing of the retained water in the panels in cold weather and deterioration of the adjacent surfaces of the plastic and the wood of the panels. Also, PVC plastic, for example, is about one third as strong as wood and the connection of a plastic a tongue protruding from a board into a plastic groove also protruding from the adjacent board is a connection of the weakest portions of the boards that is more likely to fail under lateral stress than with board-to-board connection or with only one connector between adjacent boards.  
      Thus, it would be desirable to provide an improved retaining wall assembly for use in harsh environmental conditions that utilizes wooden boards that are resistant to marine borers and that have edges that fit together for ease in aligning and connecting the panels in edge-to-edge relationship when being installed and which reduce the likelihood of movement of water and water borne material between the panels.  
      It would be desirable to produce structural panels for use in retaining walls and the like that are formed of wood and covered in an air tight plastic envelope with a groove formed at only one edge and no matching tongue at the other edge, with the groove sized and shaped to mate with the rectangular end of the panel.  
      Another object of this invention is to provide an improved panel for use in retaining walls and the like that are formed of wood and coated with plastic and have an improved connection feature at its edges that is strong, reliable and inexpensive to form and maintain.  
      Another object of this invention is to provide wooden panels covered with plastic and that include a groove formed at one edge that fits the conventional rectangular edge of the adjacent panel with a strong fit and that does not require the presence of a tongue at the edge of the adjacent panel.  
      Other objects, features and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a section of a retaining wall, showing a vertical pile, a horizontal wale, and a series of panels supported by the wale, with a section of the plastic envelope of the pile removed to illustrate that the core of the pile is formed of wood, and with a portion of the anchor rod removed.  
       FIG. 2  is an end cross sectional view of adjacent panels of  FIG. 1 , showing on one side of the figure how the panels are attached to each other, and showing on the other side of the figure the panels expanded from each other to indicate how the panels fit in edge-to-edge relationship.  
       FIG. 3  is a side elevational view of adjacent panels showing the last of the panels being moved vertically into position and guided by the lips of the previously positioned panel.  
       FIG. 4  is a perspective view of an edge portion of a panel that has been installed in the earth, showing in dash lines how the next adjacent panel will be installed.  
       FIG. 5  is a schematic illustration of how the connector lips are formed on the structural panels.  
       FIG. 6  is a perspective view of a wall formed with the structural panels of the preceding figures, but with the panels oriented horizontally in the wall structure. 
    
    
     DETAILED DESCRIPTION  
      Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views,  FIG. 1  illustrates a retaining wall  10  that has been assembled for placement between a body of water  11  and a land mass  12 , for separating the water from the land. While only a portion of the retaining wall is illustrated, it will be seen that it includes a plurality of vertical piles  14 , horizontally extending wales  16 , and a plurality of elongated, vertically oriented structural panels  18  placed in edge-to-edge relationship. The piles  14  are oriented vertically so that they can be driven downwardly through the water  11  and into the earth below so that the lower end portions of the piles are embedded in the earth and remain stabilized by the earth. Wales  16  are arranged in end-to-end relationship and extend horizontally between the piles  14  and the land mass  12 . The structural panels are elongated and extend vertically. The structural panels are driven downwardly so that their lower extremities are driven through the water into the earth below. The wales are used as a guide to orient the structural panels as they are being driven and the wales support the panels when the retaining wall structure is completed.  
      The piles, wales and structural panels preferably are made of wood that is treated with chemicals for reducing the rate of deterioration of the wood due to harsh environmental conditions, and due to marine borers and other insects. Additionally, the piles and wales and panels are coated with plastic, such as polyethylene, polyvinyl chloride, or wood flour composites, by extrusion, spraying, or other application methods. The plastic coatings may cover the entire exterior surface of the work products, including sides, edges and the end surfaces thereof. An example of a method of extruding plastic envelopes about piles, wales and panels is disclosed in co-pending U.S. patent application Ser. No. 10/891,1150.  
      Wale  16  includes a wooden core  20  that is covered with the plastic envelope. Pile  14  is wooden, as illustrated at  22  and the plastic envelope  24  is applied to the wooden core. The panels  18  are wood boards  40  with plastic coating forming the envelope  42 .  
      A tie rod  26  extends through the piles  14 , its wale  16 , and the adjacent structural panel  18 . Tie rod  26  includes an enlarged head  27  and a washer  28  on the outside surface of the pile to spread the forces applied by the tie rod to the pile. Helical threads  29  are formed on the tie rod at its distal end. An anchor rod  30  includes helical threads  31  at one end and its other end is connected to an anchor, such as poured concrete  32 . A turnbuckle  34  connects the helical threads  29  and  31  together, thereby adjustably connecting the anchor  32  by the anchor rod  30 , turnbuckle  34 , tie rod  26 , to the pile  14  of the wall structure  10 , thereby stabilizing the wall structure in its upright orientation.  
       FIGS. 2-4  show the structural panels  18 . Each structural panel is formed of a wooden board or plank  40  that is optionally treated with chemicals that tend to reduce the rate of deterioration of the boards. The boards  40  are rectangular in cross-section and are elongated. For example, a typical board used as a structural panel may be from one to four inches in thickness and from four to twelve inches in width. Other dimensions are available, depending on conditions such as the size of the boards needed at the job site, the supply of stock available to the manufacturer of the panels, and the price of the product. The example illustrated in  FIG. 2  is a board that is two inches in thickness and eight inches in width, and is rectangular in cross-section and would be of a length as may be desired at the site where it is to be constructed, for example ten feet in length.  
      The board  40  of the structural panel  18  is clad in a plastic envelope  42 , with the cladding being in abutment with the surfaces of the board. For example, opposed side surfaces  44  and  45  of the board are covered by side sheets  46  and  47  of the plastic envelope, whereas opposed edge surfaces  48  and  49  are clad by edge sheets  50  and  51 . The plastic envelope  42  will conform in shape to the exterior surfaces of the board  40 , which will be rectangular. The thickness of the plastic may vary, depending upon the type of plastic that is to be used. An example of an acceptable thickness of a polyvinyl chloride envelope is 0.070 inches, with a variance of plus or minus 0.015 inches.  
      Edge connector means  54  are applied to a first edge surface  55  of the structural panel  18 , with the opposed second edge  56  not requiring edge connector means. As shown in  FIG. 2 , the edge connector means  54  includes a pair of lips  58  and  59  that overhang the first edge  55 . The lips  58  and  59  are formed by the application of strips  60  and  61  to the opposing side sheets  46  and  47 , with a first longitudinal segment  62  of each strip adhered to the side sheets  46  and  47 , and a second longitudinal segment  63  protruding on laterally beyond the side sheets to form the lips  58  and  59 . The lips  58  and  59 , together with the first edge  55  of the structural panel, form a U-shaped recess  65 , with the lips being spaced apart a distance substantially equal to the thickness of the board  40  and the thicknesses of its side sheets  46  and  47 .  
      The second edge  56  of the structural panel does not have a tongue or groove, but remains with the conventional double right angle edge or “right angle edge.” When the second or right angle edge  56  of a structural panel  18  is placed adjacent the first edge  55  of a panel that includes the edge connector means  54 , the second edge  56  fits snugly within the U-shaped recess  65 , and the lips  58  and  59  extend about a portion of the adjacent side sheets  46  and  47  of the plastic envelope  42 . The lips  58  and  59  cover the crack between the adjacent panels.  
      As shown in  FIGS. 3 and 4 , when a series of panels have been driven into the earth  67  below the water  11 , the new panel  18 B will have its second edge  56  received in the U-shaped recess  65  formed by the lips  58  and  59  of the previous panel. The lips guide the new panel  18 B as it is being driven in the direction indicated by arrow  68 , so that the lips  58  and  59 , as well as the first edge  55  of the previously installed structural panel guide the new panel  18 B as it is being driven downwardly. This tends to guide the panels so that they will be connected together in a straight wall.  
      After the panels have been installed as indicated in  FIG. 1 , the strips  60  and  61  at the first edge  55  of each panel overlie the adjacent edges of the adjacent panels, thereby tending to block the passage of water and water-borne materials between the adjacent panels.  
      Typically, the process of forming the structural panels  18  involves the cladding of the panels with the plastic envelopes. As stated previously, this can be performed by a vacuum extrusion process described in co-pending U.S. patent application Ser. No. 10/891,930, which is incorporated herein by reference in its entirety. Generally, the process may include vacuum extrusion of the plastic about the boards so that the boards are enveloped by the plastic and the vacuum draws the plastic into direct contact with the boards, thereby substantially eliminating air from between the plastic and the boards.  
      Once the panels have been clad with plastic, the strips  60  and  61  can be extruded into position on and adhered to the panels. For example,  FIG. 5  shows in schematic form an extruder  70  that includes die openings  71  and  72  that are arranged in spaced relationship in accordance with the anticipated thickness of the structural panel  18  that includes the board  40  and its plastic envelope  42  with its side sheets  46  and  47  and its edge sheets  50  and  51  previously applied thereto. The extruder  70  is shaped so that it lays down the strips  60  and  61  that overlap the first edge  55  of the structural panel  18 . The strips are formed of a material that is compatible with the material of the plastic envelope of the board, such as polyvinyl chloride, and the temperature and consistency of the strips  60  and  61  is such that the strips become adhered to the plastic material of the side sheets  46  and  47  of the structural panel. The strips  60  and  61  are cooled so that they are cured in place and are firmly adhered to the side sheets  47  and  48  at the edge sheets  50  and  51  of the plastic envelope  42 . The over hanging segments of the strips form the lips  58  and  59  as previously described.  
      While the inventors have disclosed the strips  60  and  61  being attached by extrusion onto the panels  18 , it is anticipated that other connection methods may be used.  
      With the strips  60  and  61  being positioned on the panels the overlying portions of the strips form the lips  58  and  59  of the structural panels, and the lips function to guide the new panel, such as new panel  18 B of  FIG. 3 , as it is being moved downwardly as indicated by arrow  68  into edge abutment with respect to previously installed structural panel  18 A. In addition, the strips  60  and  61  retard the movement of water and water borne items through the panels. Moreover, the panels, being in edge-to-edge juxtaposition, with the edge of one panel supported by the U-shaped recess  65  between the lips of an adjacent panel, form a stable wall structure.  
      It will be noted that the structural panels  18  have only one pair of edge connector lips  58  and  59  formed on one edge structure  51 . The opposing edge structure  50  is free of any reconfiguration and keeps its original rectangular shape with the pair of right angle corners. This reduces the manufacturing expense and reduces the likelihood of error in the manufacturing process.  
       FIG. 6  shows another wall structure  75  formed of the structural panels  18 . The panels are oriented horizontally, stacked upon one another, with their first edges that have the protruding lips facing vertically and in registration with the rectangular second edge of the adjacent panel. The panels may be formed of equal length and their ends aligned. A series of piers such as upright I-beams  77  are driven into the earth and/or supported by poured concrete  78  in lateral alignment with each other with their oppositely facing grooves  80  facing the next adjacent I-beams. The structural panels are assembled with their opposed ends  81  received in the grooves  80  of adjacent I-beams. Other types of piers may be used if desired.  
      The overlapping lips  58  and  59  of the structural panels function to keep the panels  18  in a wall structure aligned and tend to minimize effects of lateral displacement of the panels due to warping of the panels or engagement of lateral forces against the panels, both when the panels are oriented vertically or horizontally.  
      While the piles  14  and panels  18  of  FIGS. 1-5  are disclosed as being vertically oriented, and the wales and panels horizontally oriented, and the piles of  FIG. 6  are disclosed as being vertically oriented and the panels horizontally oriented, it will be understood that these and other structural components may not be precisely installed and the terms such as “vertically”, “horizontally” and “upright” are to generally describe the orientation of the components of the wall structure with respect to one another.  
      Although a preferred embodiment of the invention has been disclosed in detail herein, it will be obvious to those skilled in the art that variations and modifications of the disclosed embodiment can be made without departing from the spirit and scope of the invention as set forth in the following claims.