Hayes, John T. (Durham, NC)
Currier, Robert G. (Roxboro, NC)

04/702925

06/20/1972

02/05/1968

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Collins and Aikman Corporation (New York, NY)

405/32

D03D25/00; E02B3/12; E02B3/04

61/3-7,37,38,47 139/20,410 52/2 160/178E

2939467	Inflatable structure	June 1960	Meyer et al.
3008213	Method of making an inflatable fabric	November 1961	Foster et al.
3188813	Article and process for wave damping	June 1965	Foster et al.
3224466	Method for weaving contoured thread connected dual wall inflatable fabric	December 1965	Grover
3299640	Means for influencing the sub-marine migration of material	January 1967	Neilsen
3396545	Method of forming concrete bodies	August 1968	Lamberton
3425228	FABRIC FORMS FOR CONCRETE STRUCTURES	February 1969	Lamberton

Caun, Peter M.

What is claimed is

1. A dual-wall fabric for use in combatting soil erosion, such as in the construction of underwater dams, comprising a pair of opposed woven fabric layers having drop stitches woven integrally with and connecting said layers, said opposed layers being constructed of materials which have dissimilar specific gravity characteristics which are respectively greater and less than that of the water with which the fabric is to be used, such that the fabric, when immersed in water and expanded between the layers, one said layer is disposed buoyantly uppermost in the water and the other said layer is spaced by gravity from the one said layer.

2. The dual-wall fabric of claim 1 wherein the first said fabric layer is constructed of polypropylene material.

3. The dual-wall fabric of claim 1 wherein the other said fabric layer is of nylon construction.

4. A method of making an artificial waterbreak for beach conservation and the like, comprising the steps of

5. providing a dual-wall fabric sheet material having connecting strands and weighted longitudinal edges in immersed relation, with the weighted edges spaced from one another on a below-water surface, a distance less than the width of the sheet material,

6. providing natural fill in the space between the below-water surface and the sheet material to force water from beneath the sheet material and to fully fill the space beneath the sheet material,

BACKGROUND OF THE INVENTION

Dual-wall fabric constructions in themselves, are known in the prior art, even those having integrally woven connecting threads, such as are used for inflatable mattresses and the like. However, the prior art is devoid of any teaching of utilizing a dual-walled fabric construction having integral drop-stitch thread connections, and which is filled with a filler material, preferably of the structural type, such as cast concrete, grout, cement or the like, or even plastics or foams. Furthermore, the prior art is devoid of any teaching of a dual-walled fabric having integral connecting threads, wherein the fabric, in its finished form is porous, to permit the passage therethrough of moisture from a castable, filler material, such as concrete or the like. Still further, the utilization of such dual-walled or even single-walled fabrics having specific gravity less than water to utilize the effect of the buoyancy of such fabrics in water in order to maintain a canopy-like shape of a fabric sheet during the filling of the same with a natural fill, such as sand, for purposes of constructing sand bars, sea walls, groins, coffer dams and the like, is nowhere taught in the prior art.

With particular regard to the construction of sand bars and the like, in many costal areas and the like, soil erosion and beach conservation are continuing problems, with sea currents, tides, etc., continuously sweeping off the natural fill from the beach surfaces. In many instances such erosion is prevented by sinking pilings and the like, or by dropping pilings or tetrapeds into the beach area. However, heretofore, sand mounds formed by prior art techniques have not successfully built up sand mounds such that the sloping mound surfaces have a greater than 25° angle with the sea floor.

Other beach conservation processes have been proposed, but none have been adapted toward quick installation resulting from the use of prefabrication techniques, resulting in economically installed sand bars and the like of a permanent nature.

SUMMARY OF THE INVENTION

The present invention seeks to obviate and overcome the above and other deficiencies in prior art dual-wall fabric constructions for structural purposes and erosion control techniques, in providing a dual-wall fabric having connecting threads integrally woven therewith, which is adapted to receive a concrete or similar fill material therein, and which permits water drainage therethrough of the concrete during setting, with various types of drop-stitch weave constructions for desirably balancing stresses, and with reinforcing rods being optionally provided.

The fabric may be constructed to have one or more walls of a material, such as polypropylene, which has a specific gravity less than that of water, such that the buoyant effect of water would normally tend to float the fabric in water. Accordingly, by desirably anchoring such a fabric, either of single or of dual-wall construction, such that it is sufficiently loose to tend to "float", and assume an arcuate shape or configuration, the fabric may then be filled either by pumping the fabric with sand or other natural fill, or by utilizing a fabric mesh of sufficiently loose construction to permit the passage of sand therethrough, whereby the fabric "dome" or the like may be filled by the natural motion of sand or other natural fill along the sea floor. The anchoring means can comprise concrete-filled fabric tubes which are connected longitudinally to the dome shaped fabric construction, along edges thereof adjacent the sea floor. If the fabric surface is of double-walled construction, the same may be pumped full of concrete or the like, after the dome shaped construction is filled with sand, and after hardening of the concrete, the structure is substantially permanent. If the fabric material of the dome construction is of single-wall thickness, a concrete or the like over-covering may be provided for the dome or sand bar thus formed.

These same principles, such as that of utilizing materials which have a specific gravity less than water to substantially float the same in water, for the purpose of sea-wall construction, are also within the scope of this invention, whereby a vertical wall may be formed by a sheet of loosely woven mesh, which is anchored at one end against the sea floor, whereby sand can gradually accumulate against sides of the sea wall, to form a sand bar or the like, the bar being adapted to be then made permanent by receiving an over-covering of concrete or the like, if desired.

Accordingly, it is a primary object of this invention to provide a novel dual-wall fabric having a pair of opposed woven fabric layers interconnected by integrally woven drop stitches, the dual-walled fabric being adapted to receive concrete or the like materials therein, for facilitating the provision of desirable structures.

It is another object of this invention to accomplish the above object, wherein the drop stitches are disposed at a desirable angular relation with respect to the opposed fabric layers, for distributing stresses and pressures in a desirable fashion, such stresses and pressures resulting from the filling of the dual-wall fabric by a desired filler material.

It is a further object of this invention to accomplish each of the above objects, wherein the fabric layers are of selected porosities and specific gravities, for the respective purposes of facilitating "breathing" of a cast filler material through the fabric walls, and for facilitating a buoyancy of the fabric when immersed in a liquid, such as water.

It is another object of this invention to provide a structural member of dual-walled fabric construction having integrally woven connecting stitches at desirable angular relationships with respect to the opposite walls, wherein reinforcing rods are provided interspersed throughout a filler material disposed between the fabric walls.

It is a further object of this invention to provided beach erosion and control structures which may be substantially prefabricated and which are relatively easy to install underwater, and which utilize, to a substantial degree, the natural fill of the sea floor in their construction, but which when installed, may be readily made permanent.

It is a further object of this invention to provide substantially permanent beach conservation structures and the like, which utilize floatable fabric materials weighted along opposite sides to form a dome construction which, when filled with sand, may be either covered or ; have an outer surface portion thereof pumped full of concrete or the like, to provide an artificial sand bar construction.

It is yet another object of this invention to provide a sea-wall construction for collecting natural fill thereabout, which may, then be covered with a concrete or cement layer, if desired, but which utilizes a buoyancy effect on the material of construction of an anchored sea wall, to maintain the same in a vertical plane underwater, during collection of the natural fill thereabout.

It is a further object of this invention to provide a novel method for the formation of beach erosion-control structures, utilizing constructions which may be substantially prefabricated and readily installed and completed in situ.

Other objects and advantages of the present invention will become readily apparent to one skilled in the art upon a detailed study of the following brief figure descriptions, the detailed descriptions of the preferred embodiment, and the drawings and appended claims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a fragmentary top perspective view of a dual-walled fabric of this invention, wherein integral connecting drop-stitch strands are illustrated disposed at acute angles to the opposed fabric walls.

FIG. 2 is an enlarged fragmentary schematic view of the dual-walled fabric of FIG. 1, as it would appear in view taken along the line II -- II of FIG. 1, looking transverse of the machine direction of weave, with the connecting strands being of repetitive generally X-shaped configuration, with a portion of the view being generally indicative of the appearance of the dual-walled fabric construction when the same is filled with concrete or the like.

FIG. 3 is a schematic end view of the dual-walled fabric of FIG. 1, taken generally in the machine direction along the line III -- III of FIG. 1, wherein the vertical disposition of the angularly disposed connecting strands, as viewed endwise, is clearly illustrated.

FIG. 4 is a view similar to that of FIG. 3, but of a dual-walled fabric construction, wherein a plurality of connecting strands are aligned, transversely of the machine in side-by-side relation, to yield a tape-like connecting stitch or web construction.

FIG. 5 is a view similar to that of FIG. 2, of a drop-stitch construction having connecting strands angularly disposed in repetitive X-shaped configuration, to provide connecting stitches, of web form, sufficient for withstanding to a large degree, pressures which would tend to separate opposed fabric layers resulting from applying a fill between the opposed fabric layers, but wherein there are illustrated reinforcing rods, disposed throughout the connecting strands, between the fabric walls.

In FIG. 6 there is illustrated a side view of a dual-walled fabric construction in schematic form, generally similar to that of FIG. 2, but wherein the individual connecting strands are disposed at right angles to each of the opposed fabric walls.

In FIG. 7 there is illustrated in side view a preliminary stage of formation of the fabric constructions of FIGS. 2 and 5, prior to separation of the opposed fabric layers.

FIG. 8 is a fragmentary top perspective view of an artificially formed sand bar formed of a dual-walled fabric of this invention which is provided with concrete-filled fabric tubes as anchoring means for the fabric during filling of the space between the fabric and ocean floor with sand or the like, the dual-walled fabric being later filled with concrete or the like, between its opposed walls to result in a permanent structure, with an end portion of similar construction also being illustrated.

FIG. 9 is an enlarged fragmentary sectional view taken generally along the line IX -- IX of FIG. 8, wherein the dual-walled fabric of construction of the bar of FIG. 8 is more clearly illustrated.

FIG. 10 is a cross-sectional view, in schematic form, of an underwater artificial sand bar formation, utilizing a floatable fabric of single-walled construction, the bar structure being otherwise similar to that of FIG. 8.

FIG. 11 is a cross-sectional view of an underwater sea-wall construction, in schematic form, wherein the sea-wall is maintained in vertical position due to the buoyant effect of the water thereon, while sand accumulates about the lower anchored end of the sea wall.

Referring now to the drawings in detail, reference is first made to FIG. 1, wherein there is illustrated a dual-wall fabric construction, generally designated by the numeral 15, which comprises spaced upper and lower walls or layers 16 and 17, respectively.

The upper wall 16 of the construction 15, as illustrated is preferably of a loose weave construction the fibrous material being of any suitable material, such as nylon, polyethylene, "foamed" polypropylene, or "foamed" nylon, but preferably of polypropylene fibers, particularly if the fabric 15 is to be used underwater, in applications where it may be desirable to vertically separate the upper layer 16 from the lower layer 17. In the latter instance, the water would have a buoyant effect on the polypropylene layer 16, due to the specific gravity (0.9) of polypropylene, as compared to that of water (1.0).

The lower wall or layer 17 may be of a more tightly woven fibrous construction, as illustrated, if porosity of this lower layer is not desirable, as for example, if the lower layer is to be used for sand containment, as illustrated in FIGS. 8 and 9. The fibrous materials from which the lower layer 17 is constructed may be nylon, or similar materials if desired.

A plurality of connecting strands 18 comprise stitches of the drop-stitch type, the strands 18 being integrally woven into the dual-wall fabric 15, and comprising the same material as that of the upper wall or layer 16. Thus, if the material comprising the strands which form the upper layer 16 is of polypropylene, the connecting strands 18 are also of polypropylene. It will be noted that there is a high density of connecting strands 18 between the walls or layers 16 and 17, for purposes of distributing tensions and pressures, in a manner to be described below.

With particular reference to FIG. 2, it is seen that the strands 18, formed by the drop-stitch method, are disposed at acute angles of substantially 45° between the upper and lower layers 16 and 17 , respectively. With reference to FIG. 3 also, it is seen that the strands 18 lie substantially in common planes, spaced transversely of the machine, or transversely of the direction of fabric travel during manufacture. Thus, each strand comprises a dropped warp strand, and is connected to or woven around transverse strands in each of the upper and lower layers 16 and 17, respectively. With continued reference to FIG. 3, it is seen that the transverse spacing of the drop strands 18, 18', 18", etc. across the machine, during formation of the dual-wall fabric 15 may be altered, as desired, to increase the transverse density of the drop strands, as desired.

As illustrated at the right side of FIG. 2, the dual-wall fabric 15 is filled with concrete 21. It is to be understood that the term "concrete" is to be construed as being sufficiently broad to encompass cement, grout, mortar, and other similar materials. The concrete 21 may be pumped or otherwise placed between the layers 16 and 17 of the dual-walled fabric 15, in wet form, and allowed to set or become "cast" therebetween, such pumping possibly exerting high pressures tending to separate or more greatly space the upper and lower walls or layers 16 and 17, respectively. The greater such pressure from pumping concrete 21 into the fabric 15, the more dense should be the placement of connecting strands 18. As has been set forth above, it may be desirable to have the upper layer 16 to be less dense than a lower layer 17, with respect to the weave construction, in order that the upper layer 16 may be more porous, to permit the passage of moisture or water therethrough as the concrete 21 becomes set or cast. In some applications, it may be desirable to have both upper and lower layers 16 and 17 to be sufficiently porous for this purpose, but in some instances, if the fabric 15 is to be used as an uppermost covering for an artificial sand bar, such as that of the type illustrated in FIG. 8, it is most desirable to have a lower fabric surface 17 of tight weave construction, to retain sand particles therein, but to have an upper fabric layer 16 of loose weave construction, to contain the concrete therein, but to permit the passage of excess water therethrough.

It is to be noted that the fill need not be concrete 21, but in many instances and applications the filling material may desirably be a suitable hardenable plastic, or foam, such as polyurethane foam. However, regardless of the filling material, foam, plastic, concrete or the like, such will have sufficient qualities for immersion of the connecting strands 18 therein.

With particular reference to FIG. 4, it is to be noted that a plurality of strands 22, 23, 24, 25 and 26 may be aligned in side-by-side relation, threaded into a repetitive X-shaped side view configuration as illustrated in FIG. 2, if desired, the end view configuration of FIG. 4 being particularly illustrative of an embodiment whereby several connecting strands 22, 23, 24, 25, 26 are operative, each similar to an individual connecting strand 18, but wherein the several strands cooperate to form a "tape-like" connecting stitch or web between spaced upper and lower fabric walls 27 and 28, respectively.

In FIG. 5, there is illustrated a dual-wall fabric, generally designated by the numeral 30, similar to that 15 of FIG. 2, and having spaced upper and lower walls or layers 31 and 32, respectively, interconnected by drop threads or strands 33, also disposed at acute angles with respect to the upper and lower walls 31 and 32. In the embodiment of FIG. 5, a plurality of reinforcing rods 34, 35, 36 and 37, are illustrated disposed in spaced relation to each of the walls 31 and 32, and retained in such positions by the crossing connecting strands 33. Thus, a structure such as that 30, may be used for other construction purposes, being reinforced with steel or iron rods, cables or the like, if desired, prior to filling the fabric 30 with concrete (not shown) or other filler material. Such rods may be hollow for carrying power and communciation wires and cables, water pipes, steam lines, etc.

In FIG. 6 there is illustrated another alternative embodiment of a dual-wall fabric 40 comprising upper and lower layers 41 and 42, connected by individual or plural strands 43, disposed between the layers 41 and 42, at substantially right angles to the plane of each of the layers 41 and 42, such strands 43 being formed by a straight through drop stitch method, should the same be desirable. The dual-wall fabric 40 may also be filled with concrete or the like, as desired.

In FIG. 7 there is illustrated a basic weave formation 50 used to attain the dual wall fabrics 15 or 30 of FIGS. 2 or 5, respectively, having opposed layers 51 and 52 connected by drop strands 53, illustrated at small acute angles with respect to the layers 51 and 52, prior to separation of the layers 51 and 52 an amount such as those layers 31 and 32 of FIG. 5, for example, and thus prior to the strands 53 taking on the X-shaped configuration of the strands 33 of FIG. 5. The strands 53 may be woven with various heights of gage wires 54, depending upon the number of crossings of the gage wires 54 and the height of the gage. The distance between the fabric layers 50 and 51 can be any desired height, to attain the desired layer spacing of FIG. 5, for example. A normal distance between the layers 31 and 32 would be within the range 0.5 to 24 inches.

With particular reference to FIG. 8, there is illustrated, in final formation, an artificially formed sand bar or the like, generally designated by the numeral 60, disposed substantially entirely beneath the upper surface 61 of water 62, as on a beach or the like, having a floor or lower surface 63, of sand or like natural fill material.

The bar 60 is adapted for channels, beaches, or the like, and may have an uppermost portion protruding out of the water 62, above the surface 61 thereof, as illustrated, if desired. The bar 60 is formed by a canopy 64 being provided, of a plurality of longitudinal portions 65 of a dual-wall fabric 15, (as illustrated in FIG. 1) stitched together along seams 66, and along opposite longitudinal edges 67 and 68 thereof having tubular fabric portions connected thereto as by stitching, or the like. Such tubular fabric portions are designated by the numerals 70 and 71, respectively. At the end of the canopy 64 formed by the plurality of fabrics or sheets 15, is an end cover 72, which also comprises a plurality of fabric portions 73, stitched together along seams 74 and along the arcuate edge 75 at the ends of each of the portions 65, to close the end thereof. At the lowermost end of the end-wall fabric 72, there is provided a tubular fabric construction 76, stitched thereto along a edge 77 thereof, similar to those tubular members 70 and 71 stitched along the sides of the canopy 64. Thus, the entire fabric construction illustrated may be prefabricated, and carried to the area of installation, as on a boat or the like, from which is may be dropped into the water 62, onto the sand surface 63, the tubular portions 70, 71 and 76, being pumped full of concrete or the like, to provide weighted portions, for retaining the canopy 64 in position. Due to the lighter-than-water material of construction of the canopy 65, or at least of the upper surface 16 thereof, the buoyant effect of water thereon will tend to fill out the shape of the canopy 64 into a generally arcuate configuration, as illustrated in FIG. 8, up to the height of the water surface 61, at which level the canopy fabric would remain until the interior of the canopy 64 is pumped full of sand, or is otherwise filled with sand or other similar natural fill material 78. After the fill material 78 "rounds out" the canopy 64, the dual-wall fabric 15, as illustrated in FIG. 9, may then be pumped full of concrete or the like, between the two layers 16 and 17, whereby the connecting strands 18 will be immersed therein, the water 61 which is present between the layers 16 and 17 being forced outwardly through the loosely woven or porous layer 16, as the dual-wall fabric fills with concrete 21. Upon setting of the concrete 21, and setting of the concrete which fills the tubular fabric portions 70, 71 and 76, the sand bar 60 becomes a substantially permanent construction. It will be apparent, that the length of the sand bar 60 may be set as desired, the individual fabric strips 65 being capable of manufacture to the desired length of a particular sand bar 60 to be constructed.

In FIG. 10 there is illustrated a fabric construction 80, generally similar to the canopy 64 of FIG. 8, having tubular portions 82 and 83 stitched or otherwise secured to opposite longitudinal edges thereof, but wherein the fabric material between the tubular portions 82 and 83 comprises a single thickness sheet of polypropylene or other lighter-than-water materials, or even a dual-wall fabric if the same is desired. In the embodiment of FIG. 10, the fabric construction 80 if placed into the water 84, with the tubular portions 82 and 83 on the bottom surface or beach floor 85 thereof, and the tubular portions 82 and 83 are again weighted, as by pumping them full of concrete or like filler. The buoyant effect of the water 84 on the polypropylene or other light sheet 81 then permits the sheet 81 to take on the form illustrated in FIG. 10, to be of arcuate construction. The particular weave of the sheet 81 permits water currents, tidal waters, or the like to carry sand or other natural bottom fill 86 through the loose weave of the sheet 81, such that it will gradually fill the void 87 beneath the arcuate sheet or canopy 81 until the sand takes on an inverted U-shaped configuration. If a temporary bar is desired, the structure may remain as illustrated in FIG. 10, or in the event that a permanent sand bar is desired, the surface 81 may be then covered with concrete-filled dual-wall fabrics such as the type illustrated in FIG. 2.

In FIG. 11 there is illustrated an alternative construction, for forming a sea-wall, wherein a sheet 90 of loosely woven polypropylene or other lighter-than-water material is provided, having secured thereto at a lower end, a tubular fabric construction 91, which when filled with concrete or other suitable material and placed on the beach floor 92, beneath the water 93, tends to anchor the sheet 90 in a vertical position, the water having a buoyant effect on the material of construction of the sheet 90. Additionally, another tubular fabric member 94 may be provided, secured to the uppermost end of the sheet 90, which may be filled with polystyrene or other buoyant pellets 95, or the like, to also facilitate maintaining the sheet 90 in vertical disposition, again utilizing the buoyant effect of the water on the pellets 95 to retain the tubular member 94 directed toward the upper surface 96 of the water. The structure illustrated in FIG. 11 is also operative during natural currents, tides, and the like, whereby sand or other natural fill 97 is conveyed along the beach surface 92, to accumulate the same on opposite sides of the surface 90, around the weighted portion 91, such sand 97 gradually accumulating upwardly, as illustrated, to form a sea wall, which may then be made permanent, as by covering the same with concrete-filled dual-wall fabric constructions, such as the type illustrated in FIG. 2, if desired.

It is to be noted that the various tubular fabric portions 70, 71, 76, 82, 83, and 91 may be of nylon construction or the like, where the specific gravity of the same is not critical.

Also, should it be desired to have vent points in a dual-wall fabric construction, such may be made by inserting a hollow rubber, or polystyrene, or like ball, between the walls of a fabric, such that, after the dual-wall fabric is grouted, or otherwise filled with concrete, the ball may be punctured, thereby providing a hole for securing any desired attachment devices to the concrete, such method of making vent points being substantially less expensive than drilling through concrete.

It is to be particularly pointed out that an advantageous feature of this invention resides in the fact that the restrictive length of the drop threads or connecting strands prevents ballooning of the opposite fabric walls during the filling of the same with concrete, any of the styrenes, foamable materials such as polyurethane, or the like, the strands also being operative for purposes of balancing the stresses which would tend toward expansion of the distance between the opposite fabric layers. Thus, the more dense the drop threads are, the greater will be the ability of the dual-wall fabric to balance stresses during filling thereof.

In those instances where the alkaline content of the concrete, grout, etc. is sufficiently high to have a tendency to react with polypropylene or the like, thus causing a degradation of the layer fibers, and particularly of the connecting strands, those strands or layer fibers or both may be nylon, to eliminate any attendent degradation problem.

It will be apparent to those skilled in the art that various modifications may be made on the various fabric containment constructions, and in the several specific applications of the same which are illustrated, along with changes in their assembly and environmental applications, all within the spirit and scope as defined in the appended claims.