US20090229214A1

US20090229214A1 - Foam-concrete rebar tie

Info

Publication number: US20090229214A1
Application number: US12/047,036
Authority: US
Inventors: Steven J. Nelson
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-03-12
Filing date: 2008-03-12
Publication date: 2009-09-17

Abstract

A fastener is disclosed having a an extension portion configured to be inserted into a first construction material such as foam, and having a stirrup portion configured to retain portion of a second construction material, such as rebar at a distance from the first construction material. A third construction material such as concrete can then be inserted (poured) in contact with the first construction material and surrounding the second construction material such that the second construction material is not directly in contact with the first construction material.

Description

BACKGROUND OF THE DISCLOSURE

Foam concrete structures are utilized in various capacities ranging from concrete stairs, drive ways, ramps, floating docks, precast walls, abutments, retaining walls with lightweight fill load distribution slabs, roadways and applications for concrete foam systems such as Geofoam™ and other applications for concrete foam structures. In general, a foam concrete structure has a central region comprised of foam material which may be expanded polystyrene (EPS) or extruded polystyrene (XEPS) with a perimeter portion of concrete therearound. Oftentimes, a tensile strength member such as rebar is positioned within the concrete. At present time, rebar, which is comprised of steel or other iron-based compositions, is a primary form of enhancing the strength of concrete to reinforce concrete structures. In general, concrete is very poor in tension, and having an insert therein, for example a metallic member such as a longitudinally extending piece of rebar, significantly enhances the strength of the concrete structure.
Now in the case of having a concrete block with a foam center portion, when a bending moment is placed upon the structure, there is a compressive force at its greatest magnitude in one portion of the block structure, whereas the opposing portion has a tensile stress imposed thereon. The concrete is used to encapsulate or provide a protective shell, for example: floatation, geofoam, floor systems, ICF's, poured-in-place and pre-cast concrete systems. The foam portion functions as floatation, lightweight fill, or insulation. Of course, the center portion has a shear force acting as welt pursuant to basic beam theory. Therefore, having a properly spaced tensile member such as rebar positioned in the foam concrete structure is important for properly positioning the rebar in the concrete to absorb the tensile stress placed thereon.
The prior art has failed to present a system, apparatus and method for properly positioning and orienting rebar at a proper depth within the outer concrete perimeter region. In some forms the rebar is positioned during a construction state in vertically and inverted orientated positions as well as a regular horizontal position. Therefore, in one form, having an apparatus to orientate the rebar in various orientations with respect to the flux field of gravity is desirable for constructing and forming a concrete/foam structure.
Further, having a proper anchoring system to attach to the foam material allows for proper positioning of the rebar holding unit. In one form, having a properly sized and dimensioned base portion allows for a sufficient amount of stability, without requiring excessive force to penetrate the foam to be mounted during production. These steps may be carried out in a manufacturing facility, or on a job site.

SUMMARY OF THE DISCLOSURE

The structure in one form described in this disclosure is a holding member having an extension portion, a base portion, and a stirrup portion. The extension portion is configured to be inserted into a rigid construction material such as a block of foam. The extension portion in one form comprises a plurality of base members with barbs which extend radially outward from the longitudinal axis of the extension portion. These barb members are constructed to add rigidity to the structure, and assist in proper positioning within the rigid construction material. These barb members are especially helpful in preventing rotational and longitudinal movement of the holding member in relation to the foam. In one form, a plurality of barb members extend from the barb members to further maintain the position of the extension within the first construction material. The extension portion may be directly coupled to or formed with the stirrup portion, or an intermediate base portion may be provided between the two. This base portion can provide a stop which will limit the depth to which the extension member can be inserted into the foam. All three elements may also be formed as a unitary structure, say of a polymer or metal.
In one form, after inserting the extension portion of the structure into the rigid construction material, a portion of an elongate construction material, such as a length of rebar, is coupled to the stirrup portion of the structure to hold the rebar a specified distance from the rigid construction material. After the rebar is positioned within the stirrup, another construction material such as concrete can be disposed in contact with the first construction material and substantially surrounding the second construction material. This will substantially encapsulate the construction materials and form a protective shell with the rebar adding support to the concrete (second material).
In one form, the barb members previously discussed also have a plurality of barb-like extensions which are configured to keep the structure from pulling out of the rigid construction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view taken along a first transverse axis of the rebar holding member;

FIG. 2 shows another side view taken along a first transverse axis;

FIG. 3 is looking longitudinally rearward along the support portion of the rebar holding member;

FIG. 4 is taken from a longitudinally forward vantage point looking at the extension portion of the rebar holding member;

FIG. 5 is a progressive view of a method of manufacture of a foam concrete block structure;

FIG. 6 shows a rebar positioned in a stirrup region of the rebar holding member which is embedded in the foam;

FIG. 7 shows a completed foam concrete structure with concrete in the outer perimeter region having a foam center region.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 7, there is an environmental view of a foam concrete structure 20. In general, the foam concrete structure 20 comprises a foam material 22 and a concrete perimeter 24. Further comprising the foam concrete structure 20 are tensile stress members such as rebars and rebar holding members 28. Further, in one form of manufacture, an outer mold member 30 can be utilized to hold the concrete 24 in its position while in an uncured state. This outer mold member 30 can either be a part of the veneer of the structure, or be removed from the concrete perimeter 24 once the concrete cures or otherwise is sufficiently rigid to hold its stationary form.
Therefore, it can be appreciated that the tensile stress member 26, which is most commonly rebar at the time of this writing, is positioned at a substantially center region 32 within the concrete perimeter 24. This positioning allows the rebar 26 to engage the surrounding concrete so as to transfer force thereto, so when for example the particular concrete perimeter wall section 34 is in tension, these tensile stresses are transferred to the rebar 26 properly, whereas the concrete aggregate itself is in general very poor at handling tension, and of course very strong in compressing as is well-known pursuant to conventional material science theory.
Therefore, as described in detail herein, the rebar holding member 28 provides utility in properly positioning the rebar during the production and manufacture of the foam concrete structure 20. Various attributes of one form of a rebar holding member will be described herein in detail with the understanding that other forms could be utilized without departing from the spirit and scope of the Applicant's broad concept.
In another embodiment, a section of tubing can be utilized instead of the tensile stress member 26. This would not only add rigidity to the material but would also add a channel for applying fluids, gases, or serve as a conduit for electrical or communication service. For example, once the structure is completed, hot water could be provided through the tubing which would heat the structure adjacent the tubing.
Referring now to FIG. 1, there is shown a side profile view of the rebar holding member 28. To aid in the general description, the axes system 10 is provided where axis 12 indicates the longitudinal forward direction. Referring ahead now to FIG. 4, there is shown a first transverse axis 14 and a second transverse axis 16. In general, the axes 14 and 16 extend radially outward from the longitudinal center axis 12″. In one form these axes are orthogonal to one another, but of course the general directions of the structures related to these axes need not be orthogonal.
Referring now to FIG. 1, it can be appreciated that in general the rebar holding member 28 has an extension portion 36 and a support portion 38. Interposed between the extension portion 36 and the support portion 38 is a base portion 40 which in one form is a transverse extending planar member configured to be positioned adjacent to the outer surface 96 of the foam center 22 described herein with reference to FIG. 5.
In general, the extension portion 36 is configured to be positioned in the foam material 22 in a manner as shown in FIG. 5. The foam material in one form may be expanded polystyrene (EPS) or extruded polystyrene (XEPS). By way of background, one form of a foam concrete structure is a concrete dock where the interior portion is comprised of foam material. The perimeter portion can be between 1 and 3 inches of concrete or more. Rebar being placed in this perimeter region, as shown in FIG. 6 and FIG. 7, greatly enhances the structural integrity of the foam concrete structure 20 (see FIG. 7).
Therefore, it can be appreciated that the extension portion 36 must provide a reasonably stable platform when inserted within the foam. As shown in FIGS. 1 and 2, there are first and second base portions 46 and 48. In one form these base portions are orthogonal to one another as shown in FIG. 4, but of course need not be orthogonal to one another. As shown in FIGS. 1 and 2, each of the first and second base portions 46 and 48 comprise a plurality of barb members. As shown in FIG. 2, the plurality of barb members 50 generally comprise, in one form, three barb members 50 a, 50 b and 50 c. In one form the barb members are of a similar radial width from a center longitudinal axis 12′ as shown at 50 a and 50 b, and in another form the barb members reduce in their radial width extension, such as where the barb 50 c is shorter than the barb 50 b. In general, the barbs provide a transverse extension where in particular the plurality of barbs 50 extend in the first transverse direction 14 as shown in FIG. 4, and provide a locking-like action when extended within the foam material.
Now referring to FIG. 1, it can be appreciated that the plurality of barb members 52 are shown, and more specifically in one form there are three sets of barb members 52 a, 52 b and 52 c. In one form, the plurality of barb members 52 can have (as shown in FIG. 2) a perimeter flange 54 which basically extends slightly outward from the surfaces 56 and 58 of the second base member 48. Present analysis indicates that this perimeter flange extension provides extra gripping of the foam material when inserted therein. Further, it can be appreciated that the barb members have a leading surface 60, which is configured to engage the foam material when thrust therein. As shown in FIG. 1, the trailing surface 62 is provided which is configured to engage the foam material to maintain the extension portion 36 mounted firmly in the core foam structure 22 (see FIG. 7).
With the foregoing description in place with regard to the extension portion 36, there will now be a discussion of the support portion (otherwise referred to as a stirrup portion) 38 with initial reference to FIG. 1. As shown in FIG. 1, in one form the support portion 38 is comprised of a base region 70. The base region 70 in one form can be comprised of base extensions 72 and 74. Positioned in the longitudinally rearward region of the support portion is a support 74 which comprises first and second arms 76 and 78. The first and second arms comprise an interior surface 80, which is configured to hold a tension member, such as a rebar 26 as shown in FIG. 5. In general, the interior surface can have a longitudinally outward region 82 which encompasses the cylindrical rebar member 26 so as to lock it in place therein. Further provided in the support 74 are the radially inward extension/fins 84 as shown in FIG. 1 and FIG. 3 within the stirrup 80. In general, the radially inward extension is configured to have a width 86 which is such that the stresses placed thereon when a rebar member is placed in the radially inward extensions plastically deform and mesh to the rebar to further lock the rebar in place. This deformation is particularly advantageous because it prevents the rebar from repositioning or otherwise slipping along the longitudinal axis of the rebar, such as if the rebar is positioned in a more vertically oriented manner. Therefore, the width 86 would be somewhat less than the width 88 is shown in FIG. 3, depending upon the material used. Using a plastic injected molded unitary piece to construct the rebar holding member 28, a desirable plastic may have a durometer rating between 50 and 100 made from nylon, polyethylene, or other suitable material.
As further shown in FIG. 5, in one form the first and second legs 76 and 78 each comprise an inward slanting surface 90 and 92. The surface of course facilitates positioning the outer surface 27 of the rebar member 26 into the central chamber region 94 of the support portion 38. Still referring to FIG. 5, the base portion 40 generally comprises a base surface 94 positioned in a longitudinally forward direction, which is configured to engage the outer surface 96 of the full material 22.
To further describe one form of the rebar holding member 28, the plurality of barbs 50 and 52 as shown in FIGS. 1 and 2 are arranged such that, for example, the barb 50 a is offset by approximately 90° and interposed between the barbs 52 a and 52 b. Present analysis indicates that this transversely offset and interposed relationship provides greater engagement of the surrounding foam material when the extension portion 36 is embedded within the foam 22 as shown in the lower portion of FIG. 5. Of course other forms of a barb can be employed and the above description is one form of carrying out the applicant's concept.
Analysis upon the overall dimensions of the rebar holding member 20 will now be presented. As shown in FIGS. 1 and 2, these dimensions are in one form substantially to scale, and in one form 95% of an actual prototype. Of course the scope of the concept is not limited to the specified dimensions of the figures; however, for purposes of included subject matter, the figures are to scale of one embodiment (plus or minus 20%) as to the actual dimensions and the relative dimensions between portions of the rebar holding member 28 itself. In other words, it has been found that having a length from the most forward location 96 from the base surface 94 of approximately 3 11/16″ provides a desirable combination of stability of the rebar holding member 28 when fully embedded in the foam 22 (see FIG. 6), and ease of force required to position and force the extension portion 36 in the foam. Further, having the first and second base portions 46 and 48 which extend longitudinally provide a sufficient amount of rigidity to hold the rebar and further provide a sufficiently narrow cross-section (see FIG. 4) to fit within the foam material 22, which as noted above, in one form is EPS. The stirrup can be higher, for example three-six inches (plus or minus say 20% in broader range), such as when utilizing a low distribution slab where the layer of concrete may be a thick layer so the rebar is positioned substantially in a central region thereof. In the broader scope, with a low distribution slab of say twelve inches, the stirrup region can extend vertically six inches or more. Even with the longer stirrup region, it has been found using the EPS foam that having the distance of approximately just under 4 inches (±30% in one form depending on the nature of the foam) provided a desirable combination of stability and ease of force depressing within CPS foam.
Therefore, as shown in FIG. 5, the force vector 100 is applied to the rebar holding member 28. The force 100 can be by way of an impact force such as a mallet-like member, or directly pushed by one who is constructing a foam concrete structure. When the extension portion 36 is fully inserted or at least substantially inserted within the foam 22, in one form the base surface 94 is pressed thereagainst and the rebar 26 can be properly positioned within the central chamber region 94. As shown in FIG. 6, a plurality of rebar members 26 a and 26 b can be positioned within the various rebar holding members 28. The support portion 38 is generally arranged to position the rebar a prescribed distance 102 from the outer surface 96 of the foam 22 (EPS in one form), and further positioned a prescribed distance 104 from the interior wall 108 of the outer mold member 30.
FIG. 6 illustrates one method of manufacture where some form of outer mold member 30 is utilized in a lower wail or a lateral wall as shown in FIG. 6. This outer mold member 30 can be a part of the final structure or removed thereafter. The interior wall 108 positions the un-cured concrete and maintains the desired form of the concrete until the concrete cures. The upper region 110 can additionally be poured and have concrete filled therein as shown FIG. 7. Therefore, it can be appreciated that a foam concrete structure 20 can be more readily constructed with a higher degree of confidence of the orientation in position of the rebar contained therein. The rebar may be specified to be positioned in a central region of the overall width of the concrete layer, such as the region indicated at 32 in FIG. 7.
In general, the device can be utilized in various forms, such as concrete sandwich panels, which in one form are poured in place, or alternatively can be pre-cast. Further, the device can be utilized in other forms, such as insulated heated floors, or further, precast concrete joists, decking, floors, or roofs and various compositions thereof. For example, the device could be utilized similar to decking for insulated reinforced concrete floor such as Decklite™ from Benchmark Foam, Inc. and other similar products from other manufactures.
While the present invention is illustrated by description of several embodiments and while the illustrative embodiments are described in detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications within the scope of the appended claims will readily appear to those sufficed in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of Applicants' general concept.

Claims

1. A rebar holding member configured to be positioned in a foam material having an outer surface, the rebar holding member comprising:

a. an extension portion having a longitudinal axis, the extension portion having a plurality of barb members extended radially outward from the longitudinal axis;

b. a base portion having a base surface located in a forward longitudinal direction;

c. a stirrup portion having a base region and a rebar holding region, the rebar holding region comprising first and second arms comprising an interior surface configured to hold a rebar member therein;

d. whereas the base region maintains a minimum prescribed distance from the base surface which is configured to be placed adjacent to the foam material.

2. The rebar holding member as recited in claim 1 where the plurality of barb members are arranged such that a longitudinally rearward barb member extends radially further outward than a longitudinally forward barb member.

3. The rebar holding member as recited in claim 1 where the plurality of barb members comprise a first transverse axis and a second transverse axis where a first set of barbs are aligned substantially in the direction of the first transverse axis and a second set of barbs are aligned substantially in the second transverse axis direction.

4. The rebar holding member as recited in claim 3 where the first set of barbs are spaced so as to be longitudinally offset and interposed between the second set of barbs.

5. The rebar holding member as recited in claim 4 where the second set of barbs substantially extend in the second transverse direction and comprise a perimeter flange portion which extends in the first transverse direction.

6. The rebar holding member as recited in claim 1 where the interior surface of the rebar holding region has a plurality of radially inward extensions having a width sufficiently narrow so the extensions undergo plastic deformation when the rebar is placed between the first and second arms of the rebar holding region.

7. The rebar holding member as recited in claim 6 where the width of the radially inward extensions are less than one half the width of the first and second arms.

8. The rebar holding member as recited in claim 7 where the rebar holding member is configured to hold the rebar in an inverted manner.

9. The rebar holding member as recited in claim 1 where the first and second arms each provide an inward slanting surface defining a central open region configured to have a portion of rebar pass therethrough.

10. The rebar holding member as recited in claim 9 where the rebar is operatively configured to be held within the interior surface of the rebar holding region when the rebar holding region is positioned beneath the extension portion.

11. The rebar holding member as recited in claim 1 where the extension portion, base portion, and stirrup portion are formed a s a unitary structure.

12. The rebar holding member as recited in claim 11 where the unitary structure is substantially formed as a polymer.

13. A device comprising:

a. an extension portion operatively configured to be inserted into a portion of resilient material wherein the extension portion further comprises;

i. a plurality of orthogonally extending base members; and

ii. a plurality of barb members;

b. a base portion having a first side and a second side, the first side coupled to the extension portion;

c. a stirrup portion coupled to the second side of the base portion, the stirrup portion operatively configured to hold a portion of construction material.

14. The device of claim 13 wherein the extension portion, base portion, and stirrup portion are formed as a unitary structure.

15. The device of claim 14 wherein the unitary structure is formed of a polymer.

16. The device of claim 13 wherein the resilient material is substantially a foam material.

17. The device of claim 13 wherein the portion of construction material is a length of rebar.

18. The device of claim 13 wherein the portion of construction material is a length of tubing.