Abstract:
A composite form for stabilizing an earthen embankment includes a floor section and a face section and is couplable to other like forms. The floor section includes integrally formed anchoring members for securing a geogrid with at least one anchoring rod. Advantageously, the face section of the form may included integrally formed hydroseeding screens. Also disclosed is a structure for stabilizing an earthen embankment, the structure comprising such a support form together with a geogrid anchored to the floor section of the form advantageously by a pair anchoring rods, an end portion of the geogrid being wrapped back and forth around the anchoring rods.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is related to U.S. provisional application No. 60/490,282 filed Jul. 28, 2003, entitled “COMPOSITE FORM FOR STABILIZING EARTHEN EMBANKMENTS”, naming Michael Charles Kallen as the inventor. The contents of the provisional application are incorporated herein by reference in their entirety, and the benefit of the filing date of the provisional application is hereby claimed for all purposes that are legally served by such claim for the benefit of the filing date. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to support forms and structures for stabilizing earthen embankments.  
       BACKGROUND OF THE INVENTION  
       [0003]     It is well known in the prior art to stabilize an earthen embankment with support forms and associated geogrids extending rearwardly from the support forms into the embankment. In many cases, the support forms are wire cage structures which have a simple geometry but which are not necessarily well adapted for ease of manufacture or ease of use. Further they are not necessarily well adapted to enable one support form to be coupled above and below with other like support forms, and they are not necessarily well adapted to enable a soft geogrid to be easily anchored to the support form in a manner which enables a secure connection with minimal detrimental stress on the geogrid. Moreover, existing designs generally do not contemplate support forms which are designed to facilitate hydroseeding not only at a construction site but also at a remote site prior to installation at a construction site.  
       SUMMARY OF THE INVENTION  
       [0004]     In accordance with the present invention, there is provided a composite form for stabilizing an earthen embankment, the form comprising a floor section, a face section, a first coupling means integral with the form for coupling the form with a like form extending above the form, and a second coupling means integral with the form for coupling the form with a second like form extending below the form.  
         [0005]     The floor section extends longitudinally rearwardly from a forward end of the floor section to a rearward end of the floor section, and includes a plurality of horizontally spaced anchoring members formed integrally with the floor section. The anchoring members are located proximate to the rearward end of the floor section and their purpose is to holdingly engage at least one geogrid anchoring rod. The floor section also includes a plurality of drainage openings extending through the floor section to permit the drainage of moisture.  
         [0006]     The face section is formed integrally with and extends longitudinally at an angle upwardly from the forward end of the floor section to a top end of said face section. It includes a first plurality of supporting ribs and a second plurality of supporting ribs, the second plurality of supporting ribs intersecting the first plurality of supporting ribs to define a plurality of regions bounded by the ribs. The upward angle of the face section will generally correspond with the slope of the embankment to be stabilized but may be up to substantially 90 degrees.  
         [0007]     Preferably, each anchoring member comprises a boss, each boss including a hole extending through the boss, the holes in all bosses being axially aligned. A linearly extending geogrid anchoring rod may then be longitudinally inserted through all of such holes.  
         [0008]     In one embodiment of the present invention, the first coupling means comprises a plurality of horizontally spaced hooking members extending upwardly from the face section. The second coupling means comprises a plurality of horizontally spaced slots extending through the floor section, the slots are preferably T-shaped and are sized to receive and couple with cooperating hooking members extending upwardly from the second like form.  
         [0009]     In another embodiment of the present invention, the form further comprises a flange extending forwardly from the top end of the face section. The first coupling means comprises a plurality of horizontally spaced hooking members extending forwardly from the forward end of said floor section, and the second coupling means comprises a plurality of horizontally spaced slots extending through the flange. The slots are again preferably T-shaped and are sized to receive and couple with cooperating hooking members extending forwardly from the second like form.  
         [0010]     Advantageously, forms in accordance with the present invention include hydroseeding screens formed integrally with the form, each one of the screens being formed within a unique one of the regions bounded by the supporting ribs.  
         [0011]     In another aspect of the present invention, there is provided a structure for stabilizing an earthen embankment, the structure comprising a support form as described above in combination with a geogrid anchored to the floor section of the form by at least one and preferably a pair of geogrid anchoring rods. In cases where a pair of anchoring rods are used, one of the rods extends through the anchoring members. The other rod abuts against the anchoring members. An end portion of the geogrid is advantageously wrapped back and forth around the anchor rods so as to tighten thereon when the geogrid is pulled in longitudinal tension away from said floor section.  
         [0012]     Using a pair of anchor rods in the foregoing manner enables a geogrid to be anchored quickly efficiently without imposing undesirable stresses on the geogrid when the geogrid is tensioned. Another point to note is that the strength of the anchoring connection (viz. the “pull-out” factor) will proportionately increase as the tension applied to the geogrid is increased. Further, the anchoring connection is not dependent on placing backfill on the connection to provide resistance and is hence necessarily independent of the quality of such backfill. The frictional resistance which backfill may have to offer is immaterial to the connection strength.  
         [0013]     The invention will now be described in more detail with reference to following drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a partially cut-away isometric view from the rear of a composite form in accordance with the present invention.  
         [0015]      FIGS. 3 and 4  are partially cut-away isometric views showing the connection of two forms like the form shown in  FIG. 1 .  
         [0016]      FIG. 5  is a section elevation view showing the connection of two forms like the form shown in  FIG. 1 .  
         [0017]      FIG. 6  is a partially cut-away rear elevation of the form shown in  FIG. 1 .  
         [0018]      FIG. 7  is a rear elevation view as in  FIG. 6 , but with some fine mesh screen areas broken away to produce voids.  
         [0019]      FIG. 8  is a partially cut-away rear elevation view of a composite form in accordance with the present invention, but which does not include any fine mesh screen areas as in the case of the form shown in  FIG. 1 .  
         [0020]      FIG. 9  is a side elevation view showing the connection of a geogrid to the form shown in  FIG. 1 .  
         [0021]      FIG. 10  is a perspective view from the front of another composite form in accordance with the present invention.  
         [0022]      FIG. 11  is a perspective view from the rear showing the connection of the form shown in  FIG. 10  with two like forms.  
         [0023]      FIG. 12  is a section elevation view showing the connection of two forms like the form shown in  FIG. 10 . 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0024]     Referring now to  FIGS. 1-6 , there is shown a composite form generally designated  15  for stabilizing an earthen embankment (not shown). Form  15  comprises a vertically extending rectangular face section generally designated  20  integrally formed with a horizontally extending floor section generally designated  40  extending horizontally rearwardly therefrom.  
         [0025]     Face section  20  includes a grid formed by a plurality of vertically extending supporting ribs  22  and a plurality of horizontally extending supporting ribs  24  which intersect ribs  22 . A fine mesh screen  26  (herein referred to as a hydroseeding screen) is integrally formed within each intervening region between ribs  22 ,  24 . As best seen in  FIG. 2 , each hydroseeding screen  26  comprises a plurality of vertically extending ribs  28  and a plurality of horizontally extending ribs  30  which intersect ribs  28  in a manner which defines a plurality of square apertures  31  extending through face section  20 .  
         [0026]     The purpose of ribs  22 ,  24  is to provide structural strength to face section  20 . The purpose of hydroseeding screens  26  is to facilitate hydroseeding. More particularly, screens  26  provide a foundation integral with form  15  against which a desired plant growth medium (not shown) can be hydrosprayed from the rear of the form. When seeds contained in the medium subsequently sprout, apertures  31  provide paths through which the resulting plants can grow. While such hydrospraying may be performed at a construction site, screens  26  advantageously enable forms to be hydrosprayed at a remote site where the process may be controlled and managed more efficiently. The hydrosprayed forms are then transported from the remote site for installation at a construction site.  
         [0027]     Horizontally spaced T-shaped slots  32  extend through face section  20  for engaging diagonal reinforcing struts  60 . A plurality of horizontally spaced hooking members  34  extend upwardly from face section  20  for engaging another form like form  15  (e.g. form  15   a  as shown in  FIGS. 3-5 ) that may be positioned directly above form  15 .  
         [0028]     Floor section  40  includes openings in the form of a plurality of horizontally spaced elongated drainage slots  42  extending between ribs  44 . Further, floor section  40  includes a plurality of horizontally spaced T-shaped slots  46 . The purpose of slots  42  is to enable moisture to pass through floor section  40  when required. The purpose of slots  46  is to enable form  15  to be coupled with another like form when it is considered desirable to do so.  
         [0029]     Floor section  40  also includes a plurality of horizontally spaced, integrally formed bosses or anchoring members  47  for anchoring a soft geogrid (not shown in  FIGS. 1-6  but which is described below in more detail in relation to  FIG. 9 ). Each anchoring member  47  includes a hole  48  axially aligned with corresponding holes  48  in the other anchoring members  47  for longitudinally receiving an anchoring rod (again not shown in  FIGS. 1-6 , but see  FIG. 9  and the related description below).  
         [0030]     Horizontally spaced rectangular slots  50  extend through floor section  40  for engaging reinforcing struts  60  in cooperation with the engagement provided by slots  32  in face section  20 . For each slot  32  in face section  20 , there is an aligned slot  50  in floor section  40 . As best seen in  FIG. 1 , each reinforcing strut  60  includes at each of its ends an arrowhead-shaped hooking member  62  which can be fitted either through one of slots  32  or through one of slots  50 . When fitted through a slot  32 , base  63  is engaged by the front surface of face section  20 . When fitted through a slot  50 , base  63  is engaged by the bottom surface of floor section  40 . Preferably, struts  60  includes ball or otherwise suitably shaped stops  64  set back on the shaft of the struts to limit the distance that the struts can be pushed through slots  32 ,  50 .  
         [0031]     It should be noted that the number of aligned pairs of slots  32 ,  50  may exceed the number of struts  60  that are actually used in any given situation. Further, it should be noted that the inclusion of stops  64  is considered desirable to assist workmen during the process of installing a strut  60 , but is not considered to be essential.  
         [0032]     Apart from reinforcing struts  60  which are manufactured separately, a significant feature of form  15  is that it can be manufactured from polyurethane as an integral unit using well known pultrusion, die cutting and related processes. Alternately, it can be manufactured by known molding processes using polyolefins.  
         [0033]     The coupling of one form  15  to another like form  15   a  is indicated in  FIGS. 3-5 . In  FIG. 3 , form  15  has already been installed and backfill (not shown) will have been added rearwardly from face section  20  and on top of floor section  40 . Form  15   a  is being lowered into position with it slots  46  aligned with hooking members  34  of form  15 . In  FIG. 4 , initial coupling has been achieved with hooking members  34  of form  15  extending through slots  46  of form  15   a .  FIG. 5  also shows coupling between forms  15  and  15   a  but with form  15   a  now pulled rearwardly in the direction of arrow “T” such that front  16  of form  15   a  vertically aligns with front  16  of form  15 . In this position, hooking members  34  of form  15  are bent rearwardly.  
         [0034]     In a exemplary case, the height of face section  20  and the rearward extension of floor section  40  are each about 18 inches. The vertical and horizontal spacing between ribs  22 ,  24  is about 4 inches, and the horizontal and vertical spacing between ribs  28 ,  30  of screens  26  is about ¼ to ⅜ inches. The hole diameter of holes  48  is preferably about 1 inch or larger.  
         [0035]     With reference to screens  26 , it will be understood by those skilled in the art that a screen suitable for hydroseeding need not have square apertures  31  as illustrated. Other geometries such as round or hexagonal geometries which have a relatively fine hole spacing also will suffice. However, regardless of the geometry which is adopted, a desirable screen feature is that workers should be able to easily produce voids in selected screens with relative ease.  
         [0036]     In  FIG. 7 , a form  115  originally like form  15  has been modified by breaking away a part of selected ones of the screens  26  in the original form to produce screens  126  with voids  131 . A number of the original screens  26  remain intact. Voids  131  can be irregular in size. Their purpose is to facilitate major plantings such as ivy. Typically, the step of producing such voids may be taken in a rudimentary but efficient manner on site after the form has been initially set in position (for example, by a hammer blow or with a cordless drill.).  
         [0037]     In some cases, it may be decided not to include hydroseeding screens. For example, such a decision may occur if the aggregate size in the earthen embankment to be stabilized is relatively large. Composite form  215  illustrated in  FIG. 8  does not include any screens to facilitate hydroseeding. However, apart from the absence of such screens, the structure of form  215  may be considered substantially the same as that of form  15 . Note that form  215  is not a case where screens  26  have been broken away. It is a case where such screens were excluded from the manufacturing process.  
         [0038]     Referring now to  FIG. 9 , anchoring members  47  enable a conventional geogrid generally designated  500  to be anchored to form  15  in a very secure manner. Geogrid  500  comprises a plurality of spaced elongated tension webs  505  extending from a forward end  510  of the geogrid to a rearward end  515 , and a plurality of spaced webs  520  horizontally intersecting tension members  505 . The anchoring technique employs two elongated anchoring rods  550 ,  560 . Each rod  550 ,  560  extends transverse to the form. Rod  550  is positioned rearward of rod  560  immediately rearward of anchoring members  47 . Rod  560  extends parallel to rod  550  and longitudinally through holes  48  in anchoring members  47 . Geogrid  500  extends from its forward end  510 :  
         [0039]     first forwardly above rods  550  and  560  to a position above rod  560 ;  
         [0040]     then wrapping around rod  560  to a position below rod  560 ;  
         [0041]     then rearwardly to a position above rod  550 ;  
         [0042]     then wrapping around rod  550  to a position below rod  550 ;  
         [0043]     then forwardly to a position below rod  560 ;  
         [0044]     then wrapping around rod  560  to a position above rod  560 ;  
         [0045]     then rearwardly above rod  550  and distantly away from form  15  to its rearward end  515 .  
         [0046]     When longitudinal tension is applied to geogrid  500  in the direction of arrow T, rod  550  is pulled by the geogrid forwardly against the rearward side of anchoring member s 47 .  
         [0047]     After the geogrid is installed and tensioned, backfill (not shown) is then added in the usual manner.  
         [0048]     It will be understood by those skilled in the art that a geogrid could be anchored to form  15  using a conventional bodkin connection. However, when the geogrid is longitudinally tensioned, the transverse webs  520  of the geogrid then may be pulled against anchoring members  47 . With sufficient tension, the members may tear through the webs. The anchoring technique shown in  FIG. 9  avoids this disadvantage because geogrid  500  does not draw against the anchoring members. Rather, it draws against anchoring rods  550 ,  560  which do not stressfully engage the transverse webs of the geogrid.  
         [0049]     The embodiments described above are all ones where it is contemplated that the earthen embankment to be stabilized is a substantially vertical embankment. Face section  20  of form  15  accordingly thus extends upwardly at a 90 degree angle with respect to floor section  40 . For the purpose of stabilizing embankments having a slope of less than 90 degrees, it will be understood by those skilled in the art that the angle between the face and floor sections of form  15  may be correspondingly reduced.  
         [0050]     Referring now to  FIGS. 10-12 , there is shown another composite form generally designated  315  for stabilizing an earthen embankment (not shown). Form  315  embodies many features which are generally the same as or similar to those of form  15 .  
         [0051]     More particularly, form  315  comprises a vertically extending rectangular face section generally designated  320  integrally formed with a horizontally extending floor section generally designated  340  extending horizontally rearwardly therefrom. Face section  320  includes a grid formed by a plurality of vertically extending supporting ribs  322  and a plurality of horizontally extending supporting ribs  324  which intersect ribs  322 . As depicted in  FIGS. 10-11 , there are rows and columns of generally rectangular voids or openings  401  in the intervening regions between ribs  322 ,  324 . However, it is to be understood that hydroseeding screens like hydroseeding screens  26  of form  15  may be integrally formed within each of such openings  401  at the time form  315  is manufactured.  
         [0052]     Horizontally spaced T-shaped slots  332  extend through face section  320  for engaging diagonal reinforcing struts  260 . An integrally formed flange  380  extends forwardly from the top end of face section  320  and includes a plurality of horizontally spaced T-shaped slots  382  which partially extend into face section  320 .  
         [0053]     Floor section  340  includes openings in the form of a plurality of spaced elongated drainage slots  342 , the purpose of which slots is to enable moisture to pass through floor section  340  when required. A plurality of horizontally spaced T-shaped hooking members  334  extend forwardly from the forward end of floor section  340 —this end being integrally coincident with the bottom of face section  320 . Hooking members  334  are sized to engage and couple with slots like slots  382  mentioned above thereby permitting form  315  to be engaged from above or below with other like forms.  
         [0054]     As shown in  FIG. 11 , form  315  is coupled with two like forms  315   a ,  315   b  which horizontally abut one another. The coupling is staggered thereby allowing form  215  to hold forms  315   a ,  315   b  in abutment. In a completed installation which may comprise several tiers of abutting forms, each tier comprising several forms, the staggered coupling of forms between adjacent tiers advantageously provides enhanced overall stability because undesirable movement of any one form is directly or indirectly restrained by the other forms.  
         [0055]     A primary difference between form  315  and form  15  is the manner of coupling between like forms. In the case of form  15 , there can be some stress of hooking members  34  when like forms are coupled, tension T is applied, and hooking members  34  are bent rearwardly as shown in  FIG. 5 . In the case of form  315 , there is no comparable stress because hooking members  334  are not subject to such bending. When tension T is applied as shown in  FIG. 12 , hooking members  334  will draw against the face of the form to which they are hooked.  
         [0056]     It will be noted (best seen in  FIG. 12 ) that when like forms are coupled from above or below then there is an offset from true vertical front between one tier and the next. In an exemplary case where the length “L” of the floor sections and face sections is about 18 inches, then the angular offset Δ from true vertical may be about 3 degrees. For practical purposes, this normally will be considered insignificant.  
         [0057]     Otherwise, it is to noted that form  315  includes horizontally spaced bosses or anchoring members  347  similar to anchoring members  47  of form  15 . A geogrid like geogrid  500  can be anchored to form  315  utilizing anchoring rods like anchoring rods  550 ,  560  in essentially the same manner as geogrid  500  is anchored to form  15 .  
         [0058]     A variety of modifications, changes and variations to the invention are possible within the spirit and scope of the following claims, and will undoubtedly occur to those skilled in the art. The invention should not be considered as restricted to the specific embodiments that have been described and illustrated with reference to the drawings. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.