BACKGROUND
1. Field of the Invention
Embodiments of the present invention are generally directed to insulated concrete composite wall panels. More specifically, embodiments of the present invention are directed to shear connectors for connecting inner and outer concrete layers of insulated concrete composite wall panels.
2. Description of the Related Art
Insulated concrete wall panels are well known in the construction industry. In general, such insulated panels are comprised of two layers of concrete, including an inner layer and an outer layer, with a layer of insulation sandwiched between the concrete layers. In certain instances, to facilitate the connection of the inner concrete layer and the outer concrete layer, the concrete layers may be tied together with one or more shear connectors to form an insulated concrete composite wall panel (“composite panel”). The building loads typically resolved by a composite insulated wall panel are wind loads, dead loads, live loads, and seismic loads. The shear connectors are, thus, configured to provide a mechanism to transfer such loads, which are resolved by the shear connectors as shear loads, tension/compression loads, and/or bending moments. These loads act can alone, or in combination. Tension loads are known to cause delamination of the concrete layers from the insulation layer. The use of shear connectors in concrete wall panels, thus, transfer shear and tension/compression loads so as to provide for composite action of the concrete wall panels, whereby both layers of concrete work together as tension and compression members.
Previously, shear connectors have been designed in a variety of structures and formed from various materials. For instance, previously-used shear connectors were often made from steel. More recently, shear connectors have been made from glass or carbon fiber and epoxy resins. The use of these newer materials increases the overall thermal efficiency of the composite panel by allowing less thermal transfer between the inner and outer concrete layers.
The continuing evolution of building energy codes has required buildings to be more efficient, including thermally efficient. To meet new thermal efficiency requirements in concrete wall panels, the construction industry has begun using thicker layers of insulation (and thinner layers of concrete) and/or more thermally efficient insulation within the panels. However, reducing the amount of concrete used in the panels will generally educe the strength of the panels. As such, there is a need for a shear connector for composite panels that provides increased thermal efficiency, while simultaneously providing increased strength and durability of the composite panels. There is also a need for lighter-weight composite panels that can be easily transported, oriented, and installed.
SUMMARY
One or more embodiments of the present invention concern a shear connector for use with insulated concrete panels. The shear connector comprises an elongated core member that includes a first end and a second end, and a flanged end-piece removably secured to one of the first end or the second end of the core member. At least a portion of the flanged end-piece includes a maximum diameter that is larger than a maximum diameter of the core member. The shear connector is configured to transfer shear forces.
Additional embodiments of the present invention include an insulated concrete panel. The panel comprises an insulation layer having one or more openings extending therethrough, a first concrete layer adjacent to a first surface of the insulation layer, a second concrete layer adjacent to a second surface of the insulation layer, and a shear connecter received within one or more of the openings in the insulation layer. The shear connector includes an elongated core member comprising a first end and a second end, and a flanged end-piece removably secured to one of the first end or the second end of the core member. The flanged end-piece is embedded within the first concrete layer. The shear connector is configured to transfer shear forces between the first concrete layer and the second concrete layer, and to prevent delamination of the first concrete layer and the second concrete layer.
Additional embodiments of the present invention include a method of making an insulated concrete panel. The method comprises the initial step of forming one or more openings through an insulation layer, with the insulation layer including a first surface and a second surface. The method additionally includes the step of inserting at least one cylindrical core member of a shear connector into one of the openings in the insulation layer, with the core member comprising a first end and a second end. The method additionally includes the step of securing a flanged end-piece on the second end of the core member. At least a portion of the flanged end-piece is spaced from the insulation layer. The method includes the additional step of pouring a first layer of concrete. The method includes the additional step of placing the insulation layer on the first layer of concrete, such that a portion of the insulation layer is in contact with the first layer of concrete. The method includes the further step of pouring a second layer of concrete over the second surface of the insulation layer. Upon the pouring of the second layer, the flanged end-piece connected to the second end of the core member is at least partially embedded within the second layer of concrete. The core member of the shear connector is configured to transfer shear forces between the first and second layers of concrete and to resist delamination of the first and second layers of concrete.
Embodiments of the present invention further include a shear connector for use with insulated concrete panels. The shear connector comprises an elongated core member including a first end and a second end, with at least a portion of the core member being cylindrical. The shear connector comprises a first flanged section extending from the first end of the core member, with at least a portion of the first flanged section extending beyond a maximum circumference of the core member. The shear connector additionally comprises a support element extending from the first flanged section or from an exterior surface of the core member, with at least a portion of the support element being positioned between the first flanged section and the second end of the core member, and with at least a portion of the support element extending beyond the maximum circumference of the core member. The shear connector further includes a second flanged section extending from the second end of the core member, with the second flanged section not extending beyond the maximum circumference of the core member. The shear connector is configured to transfer shear forces.
BRIEF DESCRIPTION OF THE FIGURES
Embodiments of the present invention are described herein with reference to the following figures, wherein:
FIG. 1 is a partial perspective view of an insulated concrete composite wall panel formed according to embodiments of the present invention, with the wall panel including a plurality of shear connectors extending therethrough;
FIG. 2 is a perspective view of a shear connector according to embodiments of the present invention;
FIG. 3 is an exploded view of the shear connector from FIG. 2;
FIG. 4 is a cross-sectional view of the shear connector from FIGS. 2 and 3;
FIG. 5 is a top plan view of a shear connector with a reinforcing web;
FIG. 6 is a top plan view of another embodiment of a shear connector with a reinforcing web;
FIG. 7 is a top plan view of a shear connector, particularly illustrating a portion of the shear connector being filled within concrete;
FIG. 8 is a partial cross-sectional view of a concrete wall panel with the shear connector from FIG. 7 extending therethrough, with a right side of the view being shown with concrete layers sandwiching an insulation layer, and with a left side of the view shown with the concrete layers in phantom;
FIG. 9 is a partial view of a section of insulation with a shear connector received therein;
FIG. 10 is a top plan view of a shear connector with a handle rod extending through a chamber of the shear connector, with the view particularly illustrating a portion of the chamber of the shear connector being filled within concrete;
11 is a partial cross-sectional view of a concrete wall panel with the shear connector from FIG. 10 extending therethrough, with a right side of the view being shown with concrete layers sandwiching an insulation layer, and with a left side of the view shown with the concrete layers in phantom;
FIG. 12 is a partial perspective view of an insulated concrete composite wall panel formed according to embodiments of the present invention, particularly illustrating a lifting device formed adjacent to an edge of the wall panel;
FIG. 13 is an enlarged, right-side, cross-sectional view of the wall panel and lifting device from FIG. 12;
FIG. 14 is an elevation view of the lifting device from FIGS. 12-13, particularly shown in reference to a cross-section of a shear connector;
FIG. 15 is a partial left-side cross-sectional view the wall panel from FIG. 12, particularly illustrating the lifting device in relation to a shear connector;
FIG. 16 is perspective partial view of another embodiment of a shear connector formed according to embodiments of the parent invention, with the shear connector being embedded in an insulation layer, and with the insulation layer shown in cross section;
FIG. 17 is an additional perspective view of the shear connector from FIG. 16;
FIG. 18 is a perspective partial view of yet another embodiment of a shear connector formed according to embodiments of the parent invention, with the shear connector being embedded in an insulation layer, and with the insulation layer shown in cross section;
FIG. 19 is an additional perspective view of the shear connector from FIG. 19;
FIG. 20 is a perspective partial view of yet another embodiment of a shear connector formed according to embodiments of the parent invention, with the shear connector being embedded in an insulation layer, and with the insulation layer shown in cross section;
FIG. 21 is an additional perspective view of the shear connector from FIG. 20; and
FIG. 22 is another perspective view of a shear connector according to embodiments of the present invention, particularly illustrating a single flanged end-piece threadedly secured to one end of a core member, with another flanged end-piece integrally formed with the other end of the core member.
The drawing figures do not limit the present invention to the specific embodiments disclosed and described herein. The drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the invention.
DETAILED DESCRIPTION
The following detailed description of the invention references the accompanying drawings that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense. The scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
In this description, references to “one embodiment,” “an embodiment,” or “embodiments” mean that the feature or features being referred to are included in at least one embodiment of the technology. Separate references to “one embodiment,” “an embodiment,” or “embodiments” in this description do not necessarily refer to the same embodiment and are also not mutually exclusive unless so stated and/or except as will be readily apparent to those skilled in the art from the description. For example, a feature, structure, act, etc. described in one embodiment may also be included in other embodiments, but is not necessarily included. Thus, the present technology can include a variety of combinations and/or integrations of the embodiments described herein.
As illustrated in FIG. 1, embodiments of the present invention are broadly directed to composite panels, such as composite panel 10 that comprises an inner concrete layer 12 separated from an outer concrete layer 14 by an insulation layer 16. The composite panel 10 is a “composite” panel because it includes one or more shear connectors 20 extending through the insulation layer 16 and engaged within each of the inner and outer concrete layers 12, 14. Specifically, the shear connectors 20 are configured to transfer shear loads between the inner and outer concrete layers 12, 14, thus, providing composite action of the composite panel 10 without delaminating the inner and/or outer concrete layers 12, 14 from the insulation layer 16.
The inner and outer concrete layers 12, 14 may comprise a composite material of aggregate bonded together with fluid cement. Once the cement hardens, the inner and outer concrete layers 12, 14 form rigid wall panels. The inner and outer concrete layers 12, 14 may be formed in various thicknesses, as may be required to satisfy strength and thermal efficiency requirements. For example, the thickness of each of the inner and outer concrete layers 12, 14 may be between 0.25 and 6 inches, between 0.5 and 5 inches, between 2 and 4 inches, or about 3 inches. In some specific embodiments, the inner and outer concrete layers 12, 14 may each be approximately 2 inches, approximately 3 inches, or approximately 4 inches thick.
The insulation layer 16 may comprise a large, rectangular sheet of rigid insulative material. For example, in some embodiments, the insulation layer 16 may comprise expanded or extruded polystyrene board, positioned between the concrete layers. In other embodiments, insulation layers can be formed from expanded polystyrene, phenolic foam, polyisocyanurate, expanded polyethylene, extruded polyethylene, or expanded polypropylene. In even further embodiments, the insulation layer 16 may comprise an open cell foam held within a vacuum bag having the air removed from the bag. In such a vacuum bag embodiment, the insulation layer 16 may be configured to achieve an R value of 48, even with the insulation layer 16 only being two inches thick. Regardless, the insulation layer 16 may be provided in various thicknesses, as may be required to satisfy strength and thermal efficiency requirements. For example, the thickness of the insulation layer 16 may be between 1 and 10 inches, between 2 and 8 inches, or between 5 and 7 inches. In some specific embodiments, the insulation layer 16 may be approximately 2 inches, approximately 3 inches, approximately 4 inches, approximately 5 inches, approximately 6 inches, approximately 7 thick, or approximately 8 inches thick.
As will be discussed in more detail below, the composite panel 10 of the present invention may formed with the shear connectors 20 by forming holes in the insulation layer 16 and inserting shear connectors 20 within such holes such that the shear connectors 20 can engage with and interconnect the inner and outer concrete layers 12, 14. As illustrated in FIGS. 2-4, the shear connector 20 according to embodiments of the present invention may comprise a generally hollow, cylindrical-shaped core member 22. In other embodiments, the core member 22 may be formed in other shapes, such as cone-shaped, taper-shaped, or the like. The core member 22 may be compression molded, injection molded, extruded, 3D-printed, or the like. The core member 22 may be formed from various thermally insulative materials with sufficient strength and durability to transfer loads between the inner and outer concrete layer 12, 14. For example, in some embodiments, the core member 22 may be formed from polymers, plastics, synthetic resins, epoxies, or the like. In certain embodiments, the core member 22 may be formed to include certain reinforcing elements, such as formed from synthetic resin reinforced with glass or carbon fibers. Nevertheless, in some embodiments, such as when thermal efficiency is not a priority, the core member 22 may be formed from other materials. For example, in such instances, it may be preferable to use a metal (e.g., steel) core member 22 to manufacture lightweight wall panels that are strong/durable and/or that meet a particular fire rating.
The core member 22 may be formed in various sizes so as to be useable with various sizes of insulation layers 16 and/or composite panels 10. For example, the core member 22 may have a length of between 1 and 8 inches, between 2 and 6 inches, or between 3 and 4 inches. In some specific embodiments, the core member 22 may have a length of approximately 2 inches, approximately 3 inches, approximately 4 inches, approximately 5 inches, approximately 6 inches, approximately 7 inches, or approximately 8 inches. As illustrated in FIGS. 2-4, the core member 22 may comprise a substantially hollow cylinder such that the core member 22 presents an outer diameter and an inner diameter. In such embodiments, the outer diameter (or the maximum diameter) of the core member 22 may be between 1 to 10 inches, between 2 to 8 inches, between 3 to 6 inches, or between 3 to 4 inches. As such, a ratio of the length of the core member 22 to the maximum diameter of the core member 22 may be between 1:1 to 3:1, between 1.5:1 to 2.5:1, or about 2:1. The core member 22 may have a thickness (as measured from the outer diameter to the inner diameter) of between 0.1 to 0.75 inches, between 0.25 to 0.5 inches, or about 0.33 inches. The inner diameter of the core member 22 may extend approximately the same dimension as the outer diameter less the thickness of the core member 22. For example, the inner diameter of the core member 22 may be between 1 to 10 inches, between 2 to 8 inches, between 3 to 6 inches, or between 3 to 4 inches, or about 3.5 inches.
In certain embodiments, as illustrated in FIG. 4, the core member 22 may include a separation plate 24 that extends across an interior space of the core member 22. Specifically, the separation plate 24 may be orientated generally perpendicularly with respect to a longitudinal extension direction of the core member 22 and may extend across the entire inner diameter of the core member 22. The separation plate 24 may be formed as a solid, circular piece of material, which may be the same material from which the core member 22 is formed. The separation plate 24 may, in some embodiments, be positioned generally midway about the length of the core member 22 (i.e., near a center of the core member 22), so as to separate the interior space of the core member 22 into an inner chamber 26 and an outer chamber 28. Nevertheless, in other embodiments, the separation plate 24 may be offset from the center of the core member's 22 length.
In certain embodiments, as illustrated in FIGS. 5 and 6, one or both sides of the separation plate 24 may be formed with a reinforcing section of material, such as a reinforcing web 29 that extends (1) upward and/or downward from the separation plate 24 into the inner chamber 26 and/or outer chamber 28, and/or (2) outward from the interior surface of the core member 22 through a portion of the inner chamber 26 and/or outer chamber 28. As shown in FIG. 5, the reinforcing web 29 may be in the form of a honeycomb-shaped structure that extends across the interior space of the core member 22 (e.g., contacting the interior surface of the core member 22 at multiple locations). In other embodiments, such as shown in FIG. 6, the reinforcing web 29 may be in the form of multiple interconnected, arcuate-shaped structures that extend across the interior space of the core member 22 (e.g., contacting the interior surface of the core member 22 at multiple locations). The reinforcing web 29 may be formed form the same material as the core member 22 and may be configured to increase the structural integrity of the shear connector 20 by enhancing the load-carrying capacity of the shear connector 20. Specifically, for instance, the honeycomb-shaped reinforcing web 29 may be configured to reinforce the shear connector 20 in multiple directions, so as to provide for the shear connector 20 to have consistent load-carrying properties in multiple directions (e.g., −x, −y, and/or −z directions). In certain embodiments, thermal properties of the shear connector 20 may also be enhanced by the use of an expansive foam or other insulating material used on the inside of the shear connector 20 (e.g., within the inner the inner chamber 26 and/or outer chamber 28) or between the elements of the reinforcing web 29, as applicable. As noted above, in certain embodiments, only one of the inner chamber 26 or outer chamber 28 may include the reinforcing web 29. For example, in some embodiments, as will be described in more detail below, the inner chamber 26 may be filled within concrete when forming the inner concrete layer 12. As such, it may be preferable for the inner chamber 26 to not include the reinforcing web 29 to permit the concrete to flow freely within the inner chamber 26, and for the outer chamber 28 to include the reinforcing web 29 to provide additional support and integrity for the shear connector 20.
Returning to FIG. 2-4, in certain embodiments, the shear connector 20 may also include flanged end-pieces 30 connected to each end of the core member 22. In some embodiments, the flanged end-pieces 30 may be formed (e.g., compression molded, injection molded, extruded, 3D-printed) from the same material from which the core member 22 is formed (e.g., thermally insulative resins). In other embodiments, the flanged end-pieces 30 may be formed from metals, such as stainless steel, or other materials with sufficient strength to pass loads to the core member 22 when the flanged end-pieces are connected with the core member 22.
Certain embodiments of the present invention provide for the ends of the core member 22 to be threaded, and for the flanged end-pieces 30 to be correspondingly threaded. As such, a flanged end-piece 30 may be threadedly secured to each end of the core member 22. In some embodiments, as shown in FIG. 3, the threaded portion of the core member 22 may be on an exterior surface of the core member 22 and the threaded portion of the flanged end-pieces 30 may be on an interior surface of the flanged end-pieces 30, such that the flanged end-pieces 30 may be threadedly secured to the exterior surface of the core member 22. In some alternative embodiments, the threaded portion of the core member 22 may be on an interior surface of the core member 22 and the threaded portion of the flanged end-pieces 30 may be on an exterior surface of the flanged end-pieces 30, such that the flanged end-pieces 30 may be threadedly secured to the interior surface of the core member 22. In addition to the threaded components, other embodiments of the present invention may provide for the flanged end-pieces 30 to be secured to the core member 22 via other methods of attachment, such as by adhesives (e.g., glue, concrete from the composite panel 10, etc.), fasteners (e.g., screws), or the like.
Other embodiments of the shear connector 20 may provide for one or both of the flanged end-pieces 30 to be permanently secured to the core member 22. For example, in some embodiments, one of the flanged end-pieces 30 of a shear connector 20 may be permanently attached to one end of the core member 22, such that only the other, opposite flanged end-piece 30 is configured to be removably connected (e.g., via threaded connections) to the other end of the core member 22. In still other embodiments, both of the flanged end-pieces 30 of the shear connector 20 may be permanently secured to the ends of the shear connector 20.
Turning to the structure of the flanged end-pieces 30 in more detail, as perhaps best illustrated by FIG. 3, the flanged end-pieces 30 may each comprise a cylindrical base section 32. In some embodiments, the base section 32 may be a hollow cylinder with an outer diameter and an inner diameter that presents a central opening 33. When the flanged end-pieces 30 are threaded on the core members 22, the flanged end-pieces 30 may be axially aligned with the core member 22 such that the central openings 33 of the base section 32 are in fluid communication with either the inner chamber 26 or the outer chamber 28. In embodiments in which the exterior surface of the core member 22 includes the threaded portions, the inner diameter of the base section 32 may correspond with the exterior diameter of the core member 22 so as to facilitate the threaded connection of the flanged end-pieces 30 with the core member 22. In embodiments in which the interior surface of the core member 22 includes the threaded portions, the outer diameter of the base section 32 may correspond with the interior diameter of the core member 22 so as to facilitate the threaded connection of the flanged end-pieces 30 with the core member 22. In some specific embodiments, the base section 32 may have a height between 0.5 to 5 inches, between 1 and 4 inches, between 2 and 3 inches, or about 2.5 inches.
Remaining with FIG. 3, the flanged end-pieces 30 may also include a flange section 34 that extends radially from the base section 32. In some embodiments, the flange section 34 may extend generally perpendicularly with respect to the base section 32. The flanged end-pieces 30 may have maximum diameters (extending across the flange section 34) of between 3 to 12 inches, between 4 to 16 inches, between 5 to 8 inches, or about 6.75 inches. Regardless, as illustrated in the drawings, a maximum diameter of the flanged end-pieces 30 will be greater than a maximum diameter of the core member 22 and/or of the holes formed in the insulation layer 16. For example, a ratio of the maximum diameter of the flanged-end pieces 30 to the maximum diameter of the core member 22 may be between 1.5:1 to 3:1, between 1.75:1 to 2.75:1, between 2.0:1 to 2.5:1, between 2.0:1 to 2.25:1, or about 2:1. As will be discussed in more detail blow, such maximum diameter permits the shear connector to be maintained in an appropriate position within an opening formed in the insulation layer 16.
In certain embodiments, the flange section 34 may be generally circular. However, in some embodiments, the flange section 34 may include a plurality of radially-extending projections 36 positioned circumferentially about the flange section 34. In addition, as shown in FIGS. 7 and 8, the flanged end-pieces 30 may include a plurality of tabs 38 that extend from below the flange section 34. In certain embodiments, the tabs 38 may extend from below each of the projections 36. The tabs may extend downward from the projections 36 between 0.25 and 3 inches, between 0.5 and 2 inches, or about 1 inches. In certain embodiments, the tabs 38 may be punched out from the projections 36. In such embodiments, that the tabs 38 originally formed part of the projections 36. Specifically, a tab-shaped section can be cut into the projection 36 (while a portion of the tab-shaped section remains secured to the projection 36), such that the tab 38 can be punched out, in a downward direction, away from the projection 36.
Given the shear connector 20 described above, a composite panel 10 can be manufactured. In particular, with reference to FIG. 1, manufacture of a composite panel 10 can begin by starting with a section of insulation that will form the insulation layer 16. Generally, the insulation layer 16 will be rectangular, although it may be formed in other required shapes. A plurality of substantially-circular connector openings 40 may be formed through the insulation layer 16. Such connector openings 40 may be formed using a hand/electric/pneumatic drill with a core bit. The connector openings 40 may be formed having a diameter that corresponds with the outer diameter of the core member 22 of the shear connector 20, such that core members 22 can be inserted into the connector openings 40.
Turning to FIGS. 7 and 9, upon a core member 22 being inserted into a connector opening 40, a flanged end-piece 30 can be secured to each end of each of the core members 22. In some embodiments, one of the flanged end-pieces may be secured to an end of the core member 22 prior to the core member 22 being inserted within an opening 40 of the insulation layer 16. Nevertheless, once the core member 22 has been inserted within the insulation layer 16, the flanged end-pieces 30 should each be threaded onto the end of a core member 22 until the tabs 38 (tabs 38 not shown in FIG. 9) contact an exterior surface of the insulation layer 16, as shown in FIG. 8. As such, the flange sections 34 of the flanged end-pieces 30 are spaced apart from the exterior surface of the insulation layer 16. Beneficially, the threaded portions of the core members 22 and/or the flanged end-pieces 30 permit the flanged end-pieces 30 to be secured at different extension levels onto the core members 22 (i.e., closer to or farther from a center of the core member 22). As such, the shear connector 20 can be made shorter or longer, so as to be usable with insulation layers 16 of various thicknesses by threadedly adjusting the position of the flanged end-pieces 30 with respect to the core member 22. For example, for a thinner insulation layer 16, a flanged end-piece 30 can be threaded significantly downward onto the core member 22 until the tabs 38 contact the exterior surface of the insulation layer 16. In contrast, for a thicker insulation layer, a flanged end-piece 30 may be threaded downward a relatively lesser amount onto the core member 22 until the tabs 38 contact the exterior surface of the insulation layer 16.
Turning back to FIG. 1, with a shear connector 20 inserted within one or more (or each) connector openings 40 of the insulation layer 16 the composite panel 10 can be created by forming the inner and outer concrete layers 12, 14. To begin, the outer concrete layer 14 can be formed by pouring concrete into a concrete form. Immediately following pouring the outer concrete layer 14, the insulation layer 16 with the shear connectors 20 inserted therein can be lowered into engagement with the outer concrete layer 14. As illustrated in FIG. 8, the flange sections 34 of the flanged end-pieces 30 that extend down from a outer exterior surface of the insulation layer 16 become inserted into and embedded in the outer concrete layer 14. Beneficially, the shape of the flanged end-pieces 30 (e.g., the space between the exterior surface of the insulation layer 16 and the flange section 34, the projections 36, and the central opening 33) is configured to securely engage the outer concrete layer 14 so as to facilitate transfer of loads from/to the outer concrete layer 14 to/from the shear connector 20. Reinforcement in the form of rebar (e.g., iron, steel, etc.), steel mesh, or prestress strand may also be inserted into the outer concrete layer 14. Furthermore, the concrete used in the formation of the outer concrete layer 14 may, in some embodiments, incorporate the use of high performance or ultra-high performance concrete that includes reinforcing fibers of glass, carbon, steel, stainless steel, polypropylene, or the like, so as to provide additional tensile and compressive strength to the composite panel 10. For example, a plurality of glass fiber rebars (e.g., 20-40 fiber rebars) may be bundled and held together by epoxy. Such bundles of glass fiber rebar may be added to the concrete to provide strength to the concrete.
Subsequent to placing the insulation layer 16 and the shear connectors 20 on and/or into the outer concrete layer 14, the inner concrete layer 12 can be poured onto an inner exterior surface of the insulation layer 16. As illustrated in FIG. 8, when the inner concrete layer 12 is poured, flange sections 34 of the flanged end-pieces 30 that extend up from the exterior surface of the insulation layer 16 become embedded within the inner concrete layer 12. Beneficially, the shape of the flanged end-pieces 30 (e.g., the space between the exterior surface of the insulation layer 16 and the flange section 34, the projections 36, and the central opening 33) is configured to securely engage the inner concrete layer 12 so as to facilitate transfer of loads from/to the inner concrete layer 12 to/from the shear connector 20. Reinforcement in the form of rebar, steel mesh, or prestress strand may also be inserted into the inner concrete layer 12. Furthermore, the concrete used in the formation of the inner concrete layer 12 may, in some embodiments, incorporate the use of high performance or ultra-high performance concrete that includes reinforcing fibers of glass, carbon, steel, stainless steel, polypropylene, or the like, so as to provide additional tensile and compressive strength to the composite panel 10. For example, a plurality of glass fiber rebars (e.g., 20-40 fiber rebars) may be bundled and held together by epoxy. Such bundles of glass fiber rebar may be added to the concrete to provide strength to the concrete.
Furthermore, during the pouring of the inner concrete layer 12, as illustrated in FIG. 8, concrete may flow through the central opening 33 of the flanged end-piece 30 and into the inner chamber 26 of the core member 22. However, the separation plate 24 prevents the concrete from flowing down into the outer chamber 28 of the core member 22. As such, an air pocket may be created within the outer chamber 28, with such air pocket facilitating thermal insulation between the inner and outer concrete layers 12, 14. As an additional benefit, partially filling the shear connector 20 with concrete may enhance the load-carrying capacity of the shear connector 20. In some embodiments, the concrete-filled inner chamber 26 may include one or more protruding elements 42 that extend from the interior surface of the core member 22 so as to facilitate engagement of the shear connector 20 with the concrete. It should be understood that in some embodiments, concrete from the outer concrete layer 14 may flow into the outer chamber 28, such that it may be beneficial for the outer chamber 28 to also include protruding elements 42 that facilitate the shear connector's 20 engagement with the concrete. Similarly, in some embodiments of the shear connectors 20 that include the reinforcing web 29, the components of the reinforcing web 29 may be used to facilitate engagement of the shear connector 20 with the concrete. Furthermore, as described above, the concrete used in the formation of the inner and outer concrete layers 12, 14 may, in some embodiments, incorporate the use of high performance or ultra-high performance concrete that include reinforcing fibers of glass, steel, stainless steel, polypropylene, or the like, so as to provide additional tensile and compressive strength to the composite panel 10.
As described above, the composite panel 10 may be formed in a generally horizontal orientation. To be used as wall for a building structure, the composite panel 10 is generally tilted upward to a vertical orientation. To facilitate such movement of the composite panel 10, embodiments of the present invention may incorporate the use of a lifting device to assist in the tilting of the composite panel 10. In some embodiments, as shown in FIGS. 10 and 11 the lifting device may be in the form of a handle rod 50 (otherwise known as a “dog bone”). The handle rod 50 may comprise a generally elongated rod of iron, stainless steel, or other sufficiently-strong metal. As shown in FIG. 11, the handle rod 50 may include a flared bottom end 52 and a flared top end 54. Upon the pouring of the inner concrete layer 12, the handle rod 50 may be inserted within the inner concrete layer 12 near an edge of the composite panel 10. The handle rod 50 may be inserted within the inner concrete layer 12 that is poured in an opening formed through a portion of the insulation layer 16, or may, as illustrated in FIGS. 10 and 11 (and as described in more detail below), be inserted within concrete from the inner concrete layer 12 that is filled within that inner chamber 26 of the shear connector 20. Regardless, the inner concrete layer 12 can harden or cure with the handle rod 50 embedded therein. In some specific embodiments, the handle rod 50 will be embedded within the inner concrete layer 12 to an extent that permits the top end 54 to extend out from the inner concrete layer 12. For instance, the bottom end 52 and a significant portion of a body of the handle rod 50 may be embedded within the inner concrete layer 12, while the top end 54 extends from the concrete. Beneficially, the flared shape of the bottom end 52 enhances the ability of the handle rod 50 to be engaged with the inner concrete 12. However, as noted above, the top end 54 of the handle rod 50 may be exposed so that it can be grasped to lift the composite panel 10, as will be discussed in more detail below.
As illustrated in FIGS. 10 and 11, the top end 54 of the handle rod 50 may be positioned below an outer surface of the inner concrete layer 12; however, in some embodiments, a recess 56 may be formed within a portion of the inner concrete layer 12 around the top end 54 of the handle rod 50, so as to expose the top end 54. With the top end 54 of the handle rod 50 exposed, a grasping hook (not shown) or a “dog bone brace connector” can be engaged with the top end 54 of the handle rod 50 and can be used to lift or tilt the composite panel 10 (i.e., by picking the composite panel 10 up from the edge in which the handle rod 50 is embedded) from a horizontal position to a vertical position. The grasping hook may be used by a heavy equipment machine (e.g., fork-lift, back-hoe, crane, etc.) or a hydraulic actuator for purposes of lifting the composite panel 10. To assist with the distribution of loads imparted by the handle rod 50 into the composite panel 10 during lifting, certain embodiments of the present invention provide for the handle rod 50 to be inserted within the inner chamber 26 of a shear connector 20, as shown in FIGS. 10 and 11. In some embodiments, it may be beneficial for the handle rod 50 to be inserted within one of the shear connectors 20 positioned adjacent to an edge of the composite panel 10, and particularly, within the portion of the inner concrete layer 12 that has filled in the inner chamber 26. In such a configuration, the loads imparted by the handle rod 50 to the inner concrete layer 12 may be distributed by the shear connector 20 through to the outer concrete layer 14. In some embodiments, multiple handle rods 50 may be inserted near and/or within multiple shear connectors 20 that are positioned adjacent to an edge of the composite panel 10.
In other embodiments, as shown in FIGS. 12-15, a lifting device in the form of a handle rod 60 and a hairpin support 62 may be used. The handle rod 60 may be similar to the handle rod 50 previously described, except that in place of the flared bottom end 52, the handle rod 60 may include a bottom end 64 in the form of a through-hole, as perhaps best shown in FIG. 15. As shown in FIG. 14, the hairpin support 62 may be in the form of a V-shaped piece of iron, steel, or other sufficiently strong metal. An angled corner of the hairpin support 62 may be received within the throughole of the bottom end 64 of the handle rod 60, such that legs of the hairpin support 62 may extend away from the handle rod 60. Instead of the handle rod 60 and hairpin support 62 being inserted within the inner chamber 26 of a shear connector, embodiments of the present invention may provide for the legs of the hairpin support 62 to extend on either side of a shear connector 20, as shown in FIGS. 12, 13, and 15. To accomplish such positioning of the handle rod 60 and hairpin support 62, the inner concrete layer 12 may be required to be thicker (and the insulation layer 16 thinner) over part of an edge portion of the composite panel 10, as is shown in FIG. 15.
In more detail, as shown in FIG. 12, the handle rod 60 and hairpin support 62 assembly may be used in conjunction with a shear connector 20 over a 2 foot by 2 foot square portion of the composite panel 10 near an edge of the composite panel 10 that is to be lifted (the “lifting portion” of the composite panel 10). As shown in FIG. 15, the insulation layer 16 at the lifting portion of the composite panel 10 is thinner than the remaining portions of the insulation layer 16 used in the composite panel 10. For example, the insulation layer 16 used at the lifting portion may be between 1.5 and 3.5 inches thick, between 2 and 3 inches thick, or about 2.5 inches thick. As such, the inner concrete layer 12 can be thicker at the lifting portion of the composite panel 10 so as to permit the handle rod 60 and hairpin support 62 to extend therethrough and to be sufficiently embedded therein.
With respect to the embodiments shown in FIGS. 12, 13, and 15, the inner concrete layer 12, and particularly the portion of the inner concrete layer 12 located at the lifting portion of the composite panel 10, is sufficiently thick so as to absorb the loads imparted by the handle rod 60 and hairpin support 62 when the composite panel 10 is lifted. As described previously, a top end 66 of the handle rod 60 may extend from the edge of the composite panel 10 or, alternatively, the composite panel 10 may include a recess 56 (See FIG. 13) formed in the inner concrete layer 12 around the top end 66 of the handle rod 60, so as to expose the top end 66. With the top end 66 of the handle rod 60 exposed, a grasping hook (not shown) can be engaged with the top end 66 of the handle rod 60 and can be used to lift or tilt the composite panel 10 (i.e., by picking the composite panel 10 up from the edge in which the handle rod 60 is embedded) from a horizontal position to a vertical position.
Beneficially, with the handle rod 60 and hairpin support 62 positioned close the shear connector 20, the shear connector 20 can act to distribute lifting loads imparted by the handle rod 60 and hairpin support 62 from the inner concrete layer 12 to the outer concrete layer 14. In some embodiments, as shown in FIG. 15, the flanged end-piece 30 of the shear connector 20 engaged within the inner concrete layer 12 may be threadedly shifted down further on the core member 22 such that the flanged end-piece 30 is positioned adjacent to the hairpin support 62. As such, the flanged end-piece 30 can act to further receive and distribute loads imparted by the handle rod 60 and hairpin support 62 through the shear connector 20 and to the outer concrete layer 14. Finally, as perhaps best illustrated in FIGS. 12 and 13, in some embodiments, one or more sections of shear bar 69, which may be in the form of iron or steel rods, may extend along the edge of inner concrete layer 12 through the lifting portion of the composite panel 10. Such shear bars 69 may act to distribute loads imparted by the handle rod 60 and hairpin support 62 through the inner concrete layer 12 such that the handle rod 60 and hairpin support 62 are not inadvertently extracted from the inner concrete layer 12 when the composite panel 10 is being lifted.
Although the shear connector 20 described above includes two flanged end-pieces 30 removably secured to the core member 71, embodiments of the present invention include other shear connector designs. For example, as shown in FIGS. 16-17, embodiments of the present invention may include a shear connector 70 that includes only a single flanged end-piece 30 removably secured (e.g., via threaded portions) to a first end of the core member 71 of the shear connector 70. A second end of the shear connector 70 does not include a flanged end-piece 30. Instead, one or more projection elements 72 extend down from the second end of the core member 22. The projection elements 72 are configured to be engaged within the outer concrete layer 14, such that the shear connector 70 can distribute loads between the inner and outer concrete layers 12, 14 of the composite panel 10. Beneficially, the projection elements 72 extend generally longitudinally downward from the core member 71 and do not extend laterally beyond an outer circumference of the core member 71 (i.e., a diameter extending across opposing projection elements 72 is less than or equal to the maximum diameter of the core member 71). As such, the shear connector 70 can be inserted within an opening formed in the insulation layer 16 by inserting the shear connector 70 into the opening by the second end (i.e., with the projection elements 72 entering the opening first).
FIGS. 18-19 and 20-21, illustrate additional embodiments of a shear connector, with such shear connectors having a unitary design. Specifically, shear connectors 80 (FIGS. 18-19) and 82 (FIGS. 20-21) includes a core member 84, 85, respectively, which are each generally formed as a hollow cylinder. However, as shown in the figures, at least a portion of the core member 84, 85 may be tapered from a maximum exterior diameter at a first end to a minimum exterior diameter at a second end. The shear connectors 80, 82 may have a first flanged end-piece 86, 87, respectively, which are integrally formed with the first ends of the core members 84, 85. As with the flanged end-pieces 30 previously described, the flanged end-pieces 86, 87 may have an outer diameter that is greater than the maximum outer diameter of the core members 84, 85, respectively. In addition, the shear connectors 80, 82 may include flanged end-pieces 88, 89, respectively, which are integrally formed with the second end of the core members 84, 85. In contrast to the flanged end-pieces 86, 87 on the first end of the core members 84, 84, the flanged end-pieces 88, 89 may be formed with an outer diameter that is equal to or less than the maximum outer diameters of their respective core members 84, 85. As such, the shear connectors 80, 82 can be inserted within an opening formed in the insulation layer 16 by inserting the shear connectors 80, 82 into the opening by the second end (i.e., with the flanged end-pieces 88, 89 entering the opening first).
As with the shear connector 20, it may be beneficial if the flanged end-pieces 86, 87 and 88, 89 of the shear connectors 80, 82 are spaced apart from the insulation layer 16 so as to permit the flanged end-pieces 86, 87, and 88, 89 to be embedded within and engaged with the inner and outer concrete layers 12, 14. To insure such positioning, the shear connectors 80, 82 may include one or more support elements that extending from the flanged end-pieces 86, 87 and/or from an exterior surface of the core members 84, 85. For example, as shown in FIG. 20-21, the support elements may be in the form of tabs 90 (similar to tabs 38 of the shear connector 20), which extend downward from the flange-engaging surface 87 to engage with the exterior surface of the insulation layer 16 (See FIG. 20). As shown in FIGS. 20-21, the tabs 90 may be ends of the radially-extending projections, which have been bent downward. Alternatively, as shown in FIG. 18-19, the support elements may in the form of an annular element 92 that extends from an exterior surface of the core member 84 and engages the exterior surface of the insulation layer 16 (See FIG. 18). Regardless, least a portion of the support elements is positioned between the flanged end-pieces 86, 87 on the first ends of the core members 84, 85 and the second end of the core members 84, 85. Additionally, at least a portion of the support elements extends outside the maximum outer circumference of the core members 84, 85. As such, the support elements are configured to support the shear connectors 80, 82 in a position that permits the flanged end-pieces 86, 87 and 88, 89 to be spaced from the insulation layer 16 for being sufficiently embedded in the inner and outer concrete layers 12, 14.
Although the invention has been described with reference to the exemplary embodiments illustrated in the attached drawings, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims. For example, as described above, some embodiments of the shear connector of the present invention may be formed with only a single flanged end-piece being removably connected (e.g., threadedly connected) to the core member. For instance, FIG. 22 illustrates a shear connector 100 in which only a first flanged end-piece is threadedly connected to a first end of the core member. However, the core member includes a second flanged end-piece, which is integrally formed with a second end of the core member (e.g., compression molded along with the core member). In such an embodiment, when manufacturing a composite panel 10, the first end of the core member may be initially inserted within an opening formed in an insulation layer. The shear connector may be inserted until the second flanged end-piece (i.e., the integral flanged end-piece) on the second end of the core member contacts the insulation layer (alternatively, however, it should be understood that the shear connector may include tabs that extend down from the flanged end-pieces, in which case the shear connector would be inserted until the tabs on the second flanged end-piece on the second end of the core member contact the insulation layer). With the shear connector properly inserted within the insulation layer, the first flanged end-piece can be threadedly secured onto the first end of the core member until the first flanged end-piece (or the tabs extending down from the first flanged end-piece) contact the insulation layer. Thereafter, a composite panel 10 can be manufactured by forming the concrete layers on either side of the insulation layer, as was previously described.
Patent Grant
10844600
