Composite Panel Assemblies Including Separation Prevention Shear Connectors

FIELD OF INVENTION

Embodiments of the present invention relate broadly to sandwich structures and construction methods. The embodiments assist in preventing the separation of a sandwich face plate from a sandwich core when the sandwich structure is subjected to static loadings, impacts and collisions.

BACKGROUND OF THE INVENTION

Composite constructions include two wide categories in civil engineering applications: sandwich composite and steel-concrete open deck composite. Sandwich composite structures have been adopted mainly in thermal/acoustic insulation and non- load-bearing structures such as cladding walls. Steel-concrete composite structures have been employed widely in civil constructions including composite floorings and composite bridges.

Conventional sandwich composite structures comprise two stiff face plates and a layer of lightweight core material. The core layer divides the two stiff face plates so that the sandwich structure can provide higher stiffness. The face plates of such sandwich structures are prone to separate from the core layer under transverse impact loads or high in-plane compressive loads, thus resulting in premature failure. Conventional core materials of sandwich panels include lightweight honeycombs, solid foam materials, lightweight polymers and structural trusses.

In some applications, a steel-concrete composite structure is used. This structure benefits from both the high tensile strength of steel and the compression resistance of the concrete layer. Conventional SCS composite structures generally include three parts, a pair of steel plates/deck, concrete, and shear studs. The shear

studs are either welded to each of the steel plates or through the steel deck to a steel girder, before the concrete is cast in situ. The shear stud transfers shear forces between the steel section and the concrete section. In addition, for applications in which the steel plate is subjected to compressive forces, the shear studs prevent buckling of the plate.

Certain applications may impose repetitive loadings on steel-concrete composite structures. As concrete is weak and brittle when subjected to tensile forces, and prone to damage when the service environment is hostile, steel-concrete-steel (SCS) sandwich structures are preferable. One prior art application utilizes automated friction welding of the through thickness shear studs to connect the two steel face plates in an SCS sandwich structure. The thickness of the sandwich panel is then determined by the length of the shear studs. One drawback to this system is that it is very difficult, if not impossible, to perform the necessary welding at a construction site. Such processes generally utilize a large size automated friction welding machine that is located in a factory.

One alternate solution to the use of SCS composite structures is to utilize steel- polymer-steel composite structures to withstand the various structural loadings. One suitable polymer that has been identified for this purpose is polyurethane, which provides structural bonding strength and separates the two steel plates in order to achieve a high bending stiffness. However, to provide a sufficiently high bending stiffness, the overall panel must be relatively thick. This can greatly increase the cost of the system, due to the high material cost of polyurethane. Additionally, the expensive polymer infill material is not environmentally friendly to manufacture and difficult to recycle.

An alternate prior art composite structure uses an all steel sandwich construction, where the two steel plates are separated by core webs. This structure employs laser welding to join the steel plates to the core webs. However, such construction also heavily relies on the welding equipment. In addition, there is a limitation on the thickness of weldable steel face plates. The applicable thickness usually ranges from 0.3mm to 6mm. When higher thicknesses of the steel plates are required, especially when a high punching shear resistance requirement leads to high plate thickness, laser welding is not a valid option.

The prior art systems therefore suffer from several disadvantages. The faceplates may separate from the core under both normal surface loadings and impact loadings. Other problems include the high material cost, the high construction cost, the dependency on in-factory welding equipment, and recyclability of the products.

It would therefore be a great improvement in the art if a composite structure could be developed that overcomes one or more of the above disadvantages.

SUMMARY OF THE INVENTION

One aspect of the present invention provides a sandwich composite panel assembly comprising: a first face plate having an inside and an outside surface; two or more first shear connectors coupled to said inside surface of said first face plate; a second face plate having an inside and an outside surface; and two or more second shear connectors coupled to said inside surface of said second face plate; wherein, when said panel is assembled, said first and second face plates define a cavity for receiving a filler material and each of said first shear connectors is coupled to a corresponding one of said second shear connectors within said cavity. In some embodiments, the panel assembly may further comprise a plurality of spacers located within said cavity to separate said first and second face plates for shipment.

In alternate embodiments, said first shear connectors may have a "J" shape having an elongated portion coupled to the inside surface of the first face plate and a hooked portion extending into said cavity; said second shear connectors may have a "J" shape having an elongated portion coupled to the inside surface of the second face plate and a hooked portion extending into said cavity; and said hooked portion of each of said first shear connectors couples to a respective one of said hooked portion of said second shear connectors.

In further embodiments, said first shear connectors may have a "J" shape having an elongated portion coupled to the inside surface of the first face plate and a hooked portion extending into said cavity; said second shear connectors may have a "U" shape having an open end coupled to the inside surface of the second face plate and a closed

end extending into said cavity; and. said hooked portion of each of said first shear connectors couples to a respective one of said closed end of said second shear connectors.

In other embodiments, the panel assemblies may further include a plurality of reinforcing bars, wherein: said first shear connectors may have a "U" shape having an open end coupled to the inside surface of the first face plate and a closed end extending into said cavity; said second shear connectors may have a "U" shape having an open end coupled to the inside surface of the second face plate and a closed end extending into said cavity; and said reinforcing bars extend through a plurality of said closed ends of said first shear connectors and said closed ends of said second shear connectors. In some embodiments, a portion of said reinforcing bars extend in a first direction through a portion of said closed ends, and a remainder of said reinforcing bars extend in a second direction through a remainder of said closed ends. The portion of said reinforcing bars and said remainder of said reinforcing bars may be substantially perpendicular to each other.

In further embodiments of the panel assembly, said first and second face plates may be made from a type of steel, and said first and second shear connectors may be made from metal. The first and second shear connectors may then be welded to said respective face plates.

An alternate aspect of the present invention provides a sandwich composite panel assembly comprising: a first face plate having an inside and an outside surface; a second face plate having an inside and an outside surface wherein, when said panel is assembled, said first and second face plates define a cavity for receiving a filler material; and two or more shear connectors coupled to said inside surface of said first face plate and said second face plate; wherein said shear connectors include: a first shear plate coupled to the inside surface of said first face plate; a second shear plate coupled to the inside surface of said second face plate; and a central element coupled to said first and second shear plates within said cavity.

In alternate embodiments, said central element may be selected from one of a group consisting of a hollow section, a solid section, and a spring. The first and second

shear plates may be coupled to said first and second face plates respectively using an adhesive.

In further embodiments of the panel assemblies discussed above, the filler material may be selected from a group consisting of a lightweight aggregate concrete, an ultra high strength concrete, other cementitious materials and a stiff polymer material.

The panel assemblies may further include a plurality of supporting members coupled to said first and second face plates, said supporting members defining said cavity. The supporting members may further include at least one opening to facilitate the flow of said filler material within said cavity.

An alternate aspect of the present invention provides a sandwich composite panel comprising a plurality of panel assemblies as defined above.

A further aspect of the present invention provides a method for producing a composite modular panel assembly, the method comprising the steps of: providing a first metal face plate; providing a second metal face plate; providing four elongated metal support members; and welding at least a portion of an outside surface of each of said elongated support members to each of said first and second face plates to define a cavity within said panel; wherein said four elongate metal support members provide a formwork within said cavity to contain a filler material.

In alternate embodiments of the method, each of said elongated metal support members may have a "C" shaped cross-section having a web and an upper and a lower flange extending from said web, wherein said web provides said formwork. The welding step may further include: welding an edge of said first face plate to an upper surface of said upper flange such that a portion of said flange extends beyond said edge; and welding an outside surface of said lower flange to an inside surface of said second face plate such that a portion of said second face plate extends beyond said lower flange; wherein said portion of said upper flange provides a backing strip to allow a plurality of composite modular panels to be joined together. Additionally, each of said elongated support members may include at least one opening to facilitate a flow of said filler material.

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In additional embodiments of the method according to the present invention, said composite modular panel assembly may further include a panel assembly as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be better understood and readily apparent to one of ordinary skill in the art from the following written description, by way of example only, and in conjunction with the drawings, in which:

Figure 1 illustrates a perspective view of a modular panel assembly with a portion of a top plate cut away according to an embodiment of the present invention;

Figure 2 illustrates a perspective view of a plurality of modular panel assemblies according to Figure 1 assembled together;

Figure 3 illustrates a perspective view of one embodiment of a supporting member that may be used with the modular panel assembly of Figures 1 and 2;

Figure 4a illustrates a cross-sectional view of one embodiment of a modular panel assembly of Figures 1 and 2 incorporating the supporting member of Figure 3, prior to assembly;

Figure 4b illustrates cross-sectional view of the modular panel assembly of

Figures 1 and 2 in an upside down orientation, incorporating the supporting member of Figure 3, prior to assembly;

Figure 5a illustrates cross-sectional view of an alternate embodiment of the modular panel assembly of Figures 1 and 2 incorporating the supporting member of Figure 3, prior to assembly;

Figure 5b illustrates a cross-sectional view of the modular panel assembly of Figureδa in an upside down orientation, prior to assembly;

Figure 6 illustrates a cross-sectional view of the panels of Figures 4a-5b in an assembled configuration;

Figure 7a illustrates a cross-sectional view of one embodiment of a shear connector that may be used with the modular panels of Figures 1-6;

Figure 7b illustrates a perspective view of the shear connector of Figure 7a;

Figure 8a illustrates a close-up perspective view of the shear connectors of

Figures 7a and 7b in an operational configuration of the modular panel of Figures 1-6;

Figure 8b illustrates a close-up side view of the shear connectors of Figure 8a;

Figure 8c illustrates a close-up side view of the shear connectors of Figure 8b rotated 90 degrees from the view of Figure 8b;

Figure 9a illustrates a perspective shadow view of one embodiment of a modular panel of Figure 1 incorporating the shear connectors of Figures 7a-8c;

Figure 9b illustrates a top view of the modular panel of Figure 9a;

Figure 9c illustrates a section view of the modular panel along the line A-A of Figure 9b;

Figure 9d illustrates a section view of the modular panel along the line B-B of Figure 9b;

Figure 10a illustrates a cross-sectional view of an alternate embodiment of a shear connector that may be used with the modular panels of Figures 1-6;

Figure 10b illustrates a perspective view of the shear connector of Figure 10a;

Figure 11 illustrates a close-up perspective view of the shear connectors of Figures 7a, 7b, 10a and 10b in an operational configuration;

Figure 12a illustrates a perspective shadow view of one embodiment of a modular panel of Figure 1 incorporating the shear connectors of Figures 7a, 7b, 10a and 10b;

Figure 12b illustrates a top view of the modular panel of Figure 12a;

Figure 12c illustrates a section view of the modular panel along the line A-A of

Figure 12b;

Figure 12d illustrates a section view of the modular panel of along the line B-B Figure 12b;

Figure 13 illustrates a close-up perspective view of an alternate embodiment of a modular panel assembly using the shear connector of Figures 10a and 10b;

Figure 14a illustrates a perspective shadow view of one embodiment of a modular panel assembly of Figure 1 incorporating the shear connectors of Figure 13;

Figure 14b illustrates a top view of the modular panel assembly of Figure 14a;

Figure 14c illustrates a section view of the modular panel assembly of Figure 14a along the line A-A of Figure 14b;

Figure 14d illustrates a section view of the modular panel assembly of Figure 14a along the line B-B of Figure 14b;

Figure 15a illustrates a close-up perspective view of an alternate embodiment of modular panel assembly using the shear connector of Figure 10a and 10b;

Figure 15b illustrates a cut away view of one embodiment of a modular panel assembly according to Figure 15a;

Figure 16a illustrates a perspective shadow view of the modular panel assembly of Figures 15a and 15b;

Figure 16b illustrates a top cross-sectional view of the modular panel assembly of Figure 16a;

Figure 16c illustrates a section view of the modular panel assembly of Figure 16a along the line A-A of Figure 16b;

Figure 16d illustrates a section view of the modular panel assembly of Figure 16a along the line B-B of Figure 16b;

Figure 17a illustrates a perspective view of an alternate embodiment of a shear connector that may be used with the modular panel assembly of Figures 1 -6;

Figure 17b illustrates a perspective view of an alternate embodiment of the shear connector of Figure 17a;

Figure 18 illustrates a perspective view of one embodiment of a modular panel assembly of Figures 1-6 incorporating the shear connector of Figure 17a;

Figure 19a illustrates a perspective view of an alternate embodiment of a shear connector of Figure 17a that may be used with the modular panel assembly of Figure 18; Figure 19b illustrates a cross-sectional side view of the shear connector of Figure

19a; and

Figure 20 is a block diagram of one method for producing the modular panel assembly according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figure 1 illustrates a perspective view of one embodiment of a modular panel assembly 100 according to the present invention. Generally, the panel assembly 100 is part of a sandwich structural system that includes three main components: 1) a top and bottom face plate 120, 140 to contribute the majority of stiffness to the sandwich structural system; 2) a sandwich core 160 to support the two face plates 120, 140 and to absorb energy during impact; and 3) a plurality of one or more types of shear connectors (Figures 7, 10, 17 and 19) to transfer the shear force between the face plates 120, 140 and the core layer 160. The shear connectors assist in preventing local buckling/ wrinkling of the face plates 120, 140 and separation of the face plates 120, 140 from the core 160 when subjected to impact loading. Each of the face plates 120, 160 may include a plurality of holes 104 for the purpose of core material pump grouting. If no pressure grouting is required, and the panel can be cast in a vertical manner where face plate 120 and 140 are vertically placed, no pump inlets and ventilation holes 104 are required. The panel assembly 100 may also include a plurality of supporting members 170. These wiirbe describedln more detail below with reference to Figures 3-6. ^"

While the panel assembly 100 is shown with the sandwich core 160 already in place, it is understood that embodiments of the present invention need not include the sandwich core 160. All embodiments of the panel assembly described herein may be manufactured and shipped without the core material 160. The core material 160 may then be added at an intermediate or final destination including, but not limited to, a construction site.

In the discussion which follows, it is understood that the core 160 may be made from various types of concrete, cement, polymers, or other suitable materials as desired. All references to the "concrete core" are provided for the purpose of illustration only. Similarly, in a preferred embodiment, the face plates 120, 140 may be manufactured from any one of various types of steel known to those of skill in the art. However, other metals, metal alloys and/or alternate materials may also be used without departing from the scope of the present embodiments. The discussion below referring to steel- concrete-steel (SCS) construction is provided for the purpose of illustration only.

It is also understood that references to "top", "bottom", "upper", "lower", "right", "left", and other orientational language is provided with specific reference to the drawings

for the purpose of illustration of the exemplary embodiments. Other orientations may also be possible. These orientational descriptive terms do not limit the embodiments of the invention in any way.

Figure 2 illustrates one embodiment of a modular panel 200 that may be assembled using a plurality of the modular panel assemblies 100 shown in Figure 1. While the modular panel 200 and modular panel assemblies 100 are shown as being substantially square, it is understood that other configurations, including but not limited to a rectangular configuration, may also be used. The square modular panel assemblies 100 are provided for the purposes of illustration only.

Figure 3 illustrates a perspective view of one embodiment of a supporting member 170 that may be used with the modular panel assemblies 100 of Figures 1 and 2. In this embodiment, the supporting member 170 includes a web 172 dividing an upper flange 174 from a lower flange 176. The web 172 and upper flange 174 define an upper corner 175. Similarly, the web 172 and lower flange 176 define a lower comer 177. The upper flange 174 includes a leading edge 173. Similarly, the lower flange 176 includes a leading edge 179. In some embodiments, one or more openings 178 may be included in the web 172 to facilitate the flow of the filler material that makes up the core layer 160. This will be discussed in more detail below. In this embodiment, the supporting member 170 is illustrated as having a "C" shaped cross section. However, it is understood that other cross-sections may also be used.

Figure 4a illustrates a cross-sectional view of one embodiment of a modular panel assembly 100a of Figures 1 and 2 incorporating the supporting member 170 of

Figure 3, prior to assembly. Figure 4b illustrates a cross-sectional view of a modular panel assembly 100b incorporating the supporting member 170 of Figure 3 in an upside down orientation, prior to assembly.

With continuing reference to Figures 3-4b, the two face plates 120, 140 and four supporting members 170 may form a closed cell and formwork for the core layer 160. In this embodiment, the thickness of the core layer 160 is directly dependent on the height of the web 172 of the supporting members 170.

The upper corners 175 of the supporting members 170 may be joined to an inside surface 122 of the upper face plate 120 using, for example, various spot welds 106. In this embodiment, the edge 179 of the lower flange 176 may be joined to an inside surface 142 of the lower face plate 140 of panel assembly 100 using, for example, various spot welds 109. In some embodiments, the weld 109 may be a continuous fillet weld, if desired. Figure 4b illustrates the identical construction for the modular panel assembly 100a shown in Figure 4a, with the panel assembly 100b in a reversed (top to bottom) orientation. In this embodiment, it is preferable to perform the inside welds 106 on each of the panel assemblies 100a, 100b prior to performing the outside welds 109. This may be accomplished by performing the welds prior to joining the two face plates 120, 140 together.

Figure 5a illustrates a cross-sectional view of an alternate embodiment of the modular panel assembly 100a of Figures 1, 2, 3a and 3b incorporating the supporting member 170 of Figure 3, prior to assembly. Figure 5b illustrates a cross-sectional view of a modular panel assembly 100b, which is identical to the modular panel assembly

100a of Figure 5a, except that it is oriented upside down.

With reference to Figures 3, 5a and 5b, a cantilever portion 180 of the upper flange 172 of the supporting member 170 may be joined to an edge 124 of the upper face plate 120 using, for example, various spot welds 112. In this embodiment, the edge

179 of the lower flange 176 may be joined to an inside surface 142 of the lower face plate 140 of panel assembly 100a using, for example, various spot welds 109. In some embodiments, the weld 109 may be a continuous fillet weld, if desired. Figure 5b, illustrates the identical construction as Figure 5a, with the panel assembly 100b in a reversed (top to bottom) orientation. This orientation facilitates joining the two panel assemblies 100a, 100b, as will be described below with reference to Figure 6.

As shown in Figures 4a-5b, the flanges 172, 176 of the supporting member 170 may serve as a back strip for butt welding that may be used to join a plurality of the modular panel assemblies 100 together. The various welds 106, 109, and 112 (Figure

6) may be intermittent. Their function is to hold the two face plates 120, 140 together for transportation and assembly at, for example, a construction site. Similarly, any one or all

of the welds may be continuous as desired. However, the weld 114 should be continuous to join the plurality of face plates 120 and 140 together.

Figure 6 illustrates a cross-sectional view of the panel assemblies 100a, 100b of Figures 4a-5b in an assembled configuration. The upper face plate 120 of panel assembly 100a may be joined to the lower face plate 140 of panel assembly 100b using, for example, butt welds 114. Similarly, the lower face plate 140 of panel assembly 100a may be joined to the upper face plate 120 of panel assembly 100b using, for example, butt welds 114. In some embodiments, the butt welds 114 may overlap the welds 112. While Figures 4a-6 illustrate the joining of two modular panel assemblies 100a, 100b, it is understood that similar methods can be used to join any number of modular panel assemblies 100 together as desired, thus forming modular panel 200 (Figure 2).

In some embodiments, the core layer 160 may be pre-cast before the modular panel assemblies 100a, 100b are assembled. In this case, a cavity 116 (Figure 6) may be formed between the two supporting members 170 of panel assemblies 100a, 100b.

Since the face plates 120, 140 are reinforced by the supporting members 170, and the spacing of the supporting members 170 between panel assemblies 100a, 100b is relatively small, the cavity 116 will not affect the structural performance of the assembled sandwich structural system.

In an alternate embodiment, the panel assemblies 100 may be shipped from a manufacturing facility to a desired location without the core layer 160. The core layer 160 may then be formed at the desired location. The prefabricated modular sandwich panel assemblies 100a, 100b, etc., will not yet include the core layer 160. In this embodiment, the core material 160 may flow through the openings 178 in the supporting members 170 to form the core layer 160, thus filling in the cavity 116. Note that, for this example embodiment, the number of grouting holes 104 can be reduced where they may be required for horizontal grouting and pressure grouting.

Depending on the size of the modular sandwich panel assemblies 100, and the thickness of the face plates 120, 140, individual shear connectors located within the panel assemblies 100 may be required. When the modular panel assembly 100 is small, the support members 170 may serve as shear connectors. However for most

applications, the panel assemblies 100 will be too large to eliminate the requirement for distinct shear connectors.

In some embodiments, the panel size can range from about 1 meter to about 4 meters on edge. However, it is understood that any size panel may be used with the embodiments of the present invention without departing from the scope of the appended claims. Additionally, it is understood that the panels may have different cross-sectional sizes or dimensions. The panels may also be non-planar, if desired. In embodiments in which the panels are non-planar, corresponding curved support members 170 may be used.

The thickness of the face plates 120, 140 can range from about 2 millimetres (mm) to about 20 mm. Other thicknesses may also be used. The thickness of the core 160 may range from about 60 mm to over 1 meter, as one advantage of the embodiments of the present invention is that the shear connectors impose little restriction on the thickness of the concrete core. The diameters of the various types of shear connectors shown herein may range from about 8mm to about 25mm for easy fabrication. The shear load that each shear connector can bear depends on the weaker of the ultimate connector shear capacity and the concrete bearing capacity.

In some embodiments, the panels produced in accordance with embodiments of the present invention may conform to one or more national or international standards. By way of example and not limitation, one such standard may be the EUROCODE 4, PART 1-1 BS EN 1994-1-1 standard. The design of such SCS sandwich panels may be optimized by varying the thickness of the steel plate, the height of the concrete core, the shear connector dimensions and the concrete strength.

Figure 7a illustrates a cross-sectional view of one embodiment of a shear connector 300 that may be used with the modular panel assemblies 100 of Figures 1-6. Figure 7b illustrates a perspective view of the shear connector 300 of Figure 7a. In this embodiment, a plurality of the shear connectors 300 are coupled to each of the face plates 120, 140. In this embodiment, since each of the shear connectors 300 coupled to the first and second face plates 120, 140 are substantially "J" shaped, they will be referred to as a J-J shear connector 300 in the following text. The J-J shear connectors

300 include an elongated section 302 which terminates in a first end 304. The J-J shear connectors 300 also include a curved section 306 which provides an inside curved section 308, thus forming a hook.

In a preferred embodiment, the J-J shear connectors 300 are made from metal, including, but not limited to, metal reinforcing bar. In this embodiment, the J-J shear connectors 300 can be fabricated by bending, forging, or machining reinforcing bar to the desired shape. The diameter and height of the J-J shear connectors 300 are dependent on the thickness of the core layer 160, which is dependent on the shear strength requirement of the panel assembly 100 the . If the thickness of the core 160 is too small, the diameter of the J-J connectors 300 cannot be large, in order to accommodate the minimum bending radius of the metal bar.

Figure 8a illustrates a close-up perspective view of the shear connectors 300 of Figures 7a and 7b in one operational configuration of a modular panel assembly 400 according to the present invention. Figure 8b illustrates a close-up side view of the shear connectors 300 of Figure 8a. Figure 8c illustrates a close-up side view of the shear connectors 300 of Figure 8b rotated 90 degrees from the view of Figure 8b.

Figure 9a illustrates a perspective view of the modular panel 400 incorporating the shear connectors 300 of Figures 7a-8c. Figure 9b illustrates a top view of the modular panel

400 of Figure 9a. Figure 9c illustrates a section view of the modular panel 400 of Figure

9a along the line A-A of Figure 9b. Figure 9d illustrates a section view of the modular panel 400 of Figure 9a along the line B-B of Figure 9b.

In the embodiment in which the J-J shear connectors 300 and face plates 120,

140, are made from metal, the first ends 304 of the J-J shear connectors 300 can be easily welded to the metal face plates 120, 140 using, for example, a commercially available shear stud arc welding device. As schematically presented in Figures 9a-9d, the two face plates 120, 140 may have a plurality of J-J shear connectors 300 welded in different orientations before being assembled.

For this panel assembly 400, a plurality of prefabricated spacers 404 may be used to assure a uniform thickness of the cavity 162, and the corresponding core layer 160. The spacers 404 may have any desired shape, and be made from any suitable

material that will not degrade the core 160 and face plate 120, 140 materials. One economical embodiment provides precast cylindrical or rectangular prism shaped spacers 404a, 404b respectively, using, for example, cementitious material of the same or higher grade than that of the adopted core layer material.

As best illustrated in Figures 9c and 9d, the two face plates 120, 140 may each have a number of J-J shear connectors 300 which may be aligned to pair the J-J shear connectors 300, thus coupling the face plates 120, 140 together. In a preferred embodiment, the two face plates 120, 140 may be rotated 90 degrees with respect to each other. This facilitates joining the two face plates 120, 140 such that the inside curved section 308 of the shear connectors 300 coupled to the first face plate 120 engages the inside curved section 308 of the shear connectors 300 coupled to the second face plate 140. The spacers 404 may then be placed between the two face plates 120, 140 to fully engage the J-J-connectors 300. If desired, the supporting members 170 may then be attached to the face plates 120, 140. At this point, the panel assembly 400 may then be transported to a user site. Alternately, the core material 160 may be added prior to transport.

Figure 10a illustrates a side view of an alternate embodiment of a shear connector 500 that may be used with the modular panel assemblies 100 of Figures 1-6.

Figure 10b illustrates a perspective view of the shear connector 500 of Figure 10a. In this embodiment, the shear connectors 500 are substantially "U" shaped. Each "U" shaped shear connector 500 includes a first elongate section 502 and a second elongated section 504. Each of the elongated sections 502, 504 has a corresponding end face 506, 508 respectively. Each "U" shaped shear connector 500 further includes a curved portion 510 having an inside surface 512.

Figure 11 illustrates a close-up perspective view of an alternate embodiment of a panel assembly 600 showing the shear connectors 300, 500 of Figures 7a, 7b, 10a and 10b in one operational configuration. Figure 12a illustrates a perspective view of one embodiment of a modular panel assembly 600 incorporating the shear connectors 300 of Figures 7a and 7b, and the shear connectors 500 of Figures 10a and 10b. Figure 12b illustrates a top view of the modular panel assembly 600 of Figure 12a. Figure 12c illustrates a section view of the modular panel assembly 600 of Figure 12a along the line

A-A of Figure 12b. Figure 12d illustrates a section view of the modular panel assembly 600 of Figure 12a along the line B-B of Figure 12b.

As shown in Figures 11-12d, the panel assembly 600 uses a plurality of "J" shaped shear connectors 300 coupled to the first face plate 120, and a plurality of "U" shaped shear connectors 500 coupled to the second face plate 140. This embodiment will be referred to as a J-U shear connector 300, 500 in the following discussion.

In the embodiment in which the J-U shear connectors 300, 500 and face plates 120, 140, are made from metal, the J-U shear connectors 300, 500 can be easily welded to the metal face plates 120, 140 respectively using, for example, a commercially available shear stud arc welding device. The procedure for the "J" shear connectors 300 was described in preceding paragraphs. Similarly, the end faces 506, 508 of the "U" shear connectors 500 may be welded to the face plates 140.

As schematically presented in Figures 12a-12d, the two face plates 120, 140 may have a number of J-U shear connectors 300, 500 welded in different orientations before being assembled. Preferably, the "J" shear connectors 300 and the "U" shear connectors 500 should be oriented perpendicularly prior to assembly of the panel assembly 600. This facilitates joining the two face plates 120, 140 such that the inside curved section 308 of the shear connectors 300 coupled to the first face plate 120 engage the inside curved section 512 of the shear connectors 500 coupled to the second face plate 140.

For this panel assembly 600, a plurality of prefabricated spacers 604 may be used to assure a uniform thickness of the cavity 162, and the corresponding core layer 170. The construction and placement of the spacers 604 is similar to the construction and placement of the spacers 404 previously described. As best illustrated in Figures 12c and 12d, the face plates 120, 140 may each have a number of J-U shear connectors 300, 500 respectively, which may be aligned to pair the J-U shear connectors 300, 500, thus coupling the face plates 120, 140 together. The spacers 604 may then be placed between the two face plates 120, 140 to fully engage the J-U shear connectors 300, 500. If desired, the supporting members 170 may then be attached to the face plates 120,

140. At this point, the panel assembly 600 may be transported to a user site. Alternately, the core material 160 may be added prior to transport.

As the J shear connector 300 may tend to be straightened when subjected to impact loads, a U-U shear connector may be used in pairs to provide increased shear resistance. Figure 13 illustrates a close-up perspective view of an alternate embodiment of a U-U shear connector 500 located within a modular panel assembly 700. Figure 14a illustrates a perspective view of the modular panel assembly 700 incorporating the shear connectors 500 of Figure 13. Figure 14b illustrates a top view of the modular panel assembly 700 of Figure 14a. Figure 14c illustrates a section view of the modular panel assembly 700 of Figure 14a along the line A-A of Figure 14b. Figure 14d illustrates a section view of the modular panel assembly 700 of Figure 14a along the line B-B of

Figure 14b.

In this embodiment, a plurality of reinforcing bars 710 may be arranged through each pair of U-U shear connectors 500 within the cavity 162. The attachment of the U-U shear connectors 500 to the face plates 120, 140 was previously described with reference to Figures 12a-12d, and will not be repeated here. In this embodiment, the "U" shaped shear connectors 500 may be arranged on the face plates 120, 140 to allow rows of parallel "U" shaped shear connectors 500 to line up within the cavity 162. The reinforcing bars 710 may then be inserted through openings in the "U" shaped shear connectors 500 coupled to the first face plate 120 to engage the inside surface 512 of the curved section 510, and through openings in the "U" shaped shear connectors 500 coupled to the second face plate 140 to engage the inside surface 512 of the curved section 510. A plurality of prefabricated spacers 704 may then be inserted between the first face plate 120 and the second face plate 140 such that the reinforcing bars 710 are held in place. If desired, the supporting members 170 may then be attached to the face plates 120, 140 as previously described. At this point, the panel assembly 700 may be transported to a user site as desired. Alternately, the core material 160 may be added prior to transport. In some embodiments, the reinforcing bars 710 that extend in one direction may be welded together to form a longer bar.

An alternate embodiment using the U-U shear connectors 500 is shown in Figures 15a-16d. Figure 15a illustrates a close-up perspective view of an operational

configuration of an alternate embodiment of the U-U shear connectors 500 that may be used with an alternate embodiment of a modular panel 750. Figure 15b illustrates a cut away view of one embodiment of the modular panel 750 according to Figure 15a. Figure 16a illustrates a perspective view the modular panel 750 incorporating the shear connectors 500 oriented as shown in Figures 15a and 15b. Figure 16b illustrates a top view of the modular panel 750 of Figure 16a. Figure 16c illustrates a section view of the modular panel 750 of Figure 16a along the line A-A of Figure 16b. Figure 16d illustrates a section view of the modular panel 750 of Figure 16a along the line B-B of Figure 16b.

The modular panel 750 provides for a plurality of "U" shaped shear connectors

500 coupled to the first face plate 12O ₁ and another plurality of "U" shaped shear connectors 500 coupled to the second face plate 140. In this embodiment, each of the "U" shaped shear connectors 500 on the first face plate 120 may be alternately oriented perpendicularly and slightly offset from adjacent connectors 500. Similarly, each of the "U" shaped shear connectors 500 on the second face plate 140 may be alternately oriented perpendicularly and slightly offset from adjacent connectors 500. A plurality of reinforcing bars 710 may then be inserted in two different directions through corresponding "U" shaped connectors 500 on the face plates 120, 140. In this embodiment, the reinforcing bars 710 may be inserted through openings in the "U" shaped shear connectors 500 coupled to the first face plate 120 to engage the inside surface 512 of the curved section 510, and through openings in the "U" shaped shear connectors 500 coupled to the second face plate 140 to engage the inside surface 512 of the curved section 510. In a preferred embodiment, a first portion of the plurality of the reinforcing bars 710 are inserted in a first direction, and a second portion of the plurality of reinforcing bars 710 are inserted substantially perpendicularly to the first portion of reinforcing bars 710.

A plurality of prefabricated spacers 704 may then be inserted between the first face plate 120 and the second face plate 140, such that the reinforcing bars 710 are held in place. If desired, the supporting members 170 may then be attached to the face plates 120, 140. At this point, the panel assembly 750 may be transported as desired.

Alternately, the core material 160 may be added prior to transport.

A further embodiment of a shear connector according to the present invention is shown in Figures 17a-19b. Figure 17a illustrates a perspective view of an alternate embodiment of a shear connector 550 that may be used with a modular panel 800.

Figure 17b illustrates a perspective view of an alternate embodiment of a shear connector 550a, similar to that shown in Figure 17a. Figure 18 illustrates a perspective view of one embodiment of the modular panel 800 incorporating the shear connector

550 of Figure 17. Figure 19a illustrates a perspective view of an alternate embodiment of a shear connector 570 that may be used with the modular panel 800 of Figure 18.

Figure 19b illustrates a cross-sectional side view of the shear connector 570 of Figure 19a.

The embodiments illustrated in Figures 17a and 17b employ the shear connectors 550, 550a. The shear connector 550 includes an upper shear plate 552 having an outside surface 553, and a lower shear plate 554 having an outer surface 555. A solid central element 556 (for shear connector 550 of Figure 17a), or a hollow central element 558 (for shear connector 550a of Figure 17b) may be used to connect the upper and lower shear plates 552, 554. In some embodiments, the central elements 556, 558 may be welded to the upper and lower shear plates 552, 554. In this embodiment, the upper and lower shear plates 552, 554 are shown as being disc shaped. However, it is understood that other shapes may also be used without departing from the scope of the embodiment. The height of the central element 556, 558 determines the thickness of the core layer 160.

In these embodiments, the upper and lower shear plates 552, 554 may be coupled to the first and second face plates 120, 140 respectively using, for example, a structural adhesive. Using a structural adhesive to join the shear plates 552, 554 to the face plates 120, 140 eliminates the need for welding. In operation, the structural adhesive may be applied either to the inner surface 122, 142 of the face plates 120, 140, the outer surface 553, 555 of the upper and lower shear plates 552, 554, or both. Within the working time of the adhesive, the surfaces 122, 142 and 553, 555 should be placed into contact and cured to set. One example of a suitable structural adhesive is a two- part toughened epoxy. Other types of adhesives may also be used to provide enough bond strength.

Another advantage of this embodiment is the elimination of the need to measure the spacing between the shear connectors 550. The size/diameter of the circular shear plates 552, 554, controls the spacing. Each shear connector 550 can be placed side by side to form a panel assembly 800 as illustrated in Figure 18. After the set of structural adhesive, the panel 800 is ready to support itself for transportation and assembly.' Alternately, the core material 160 may be added prior to transport. In this embodiment, no additional spacers are required before grouting of the core material 160.

As discussed above, the central element 558 may have a hollow circular cross- section as shown in Figure 17b. In this case, the load bearing area of the infill core material 160 will be increased to improve the shear strength of the composite panel 800.

An alternate embodiment of this type of shear connector is shown in Figures 19a and 19b, and designated generally as reference numeral 570. As with the previous embodiments, the shear connector 570 includes upper and lower shear plates 552, 554. The shear connector 570 includes a central element 571. In this embodiment, the central element 571 includes a spring 572 located between the upper and lower shear plates 552, 554. The upper shear plate 552 includes a connection element 574 having a recess 579 for receiving the spring 572. Similarly, the lower shear plate 554 includes a connection element 576 having a recess 580 for receiving the spring 572. In some embodiments, the spring 572 may be welded to the recesses 579, 580. Alternately, the spring 572 may be welded directly to the upper and lower shear plates 552, 554, respectively.

In some embodiments, the shear plates 552, 554 and central elements 556, 558 may be made from metal including, but not limited to, various types of steel. Alternately, the shear plates 552, 554 and central elements 556, 558 may be made from one or more types of plastic, including, but not limited to, fiber reinforced plastic. Other materials may also be used without departing from the scope of the present embodiments.

Figure 20 is a block diagram of one method, designated generally as reference numeral 900, for producing a composite modular panel assembly according to the present invention. The method includes a first step of providing a first metal face plate,

as shown with reference numeral 902. The method 900 next includes providing a second metal face plate, as shown with reference numeral 904, and providing four elongated metal support members, as shown with reference numeral 906. Next, the method 900 includes a step of welding at least a portion of an outside surface of each of said elongated support members to each of said first and second face plates to define a cavity within said panel, wherein said four elongate metal support members provide a formwork within said cavity to contain a filler material, as shown with reference numeral 908.

In some embodiments of the method 900, the welding step 908 may further include welding an edge of the first face plate to an upper surface of the upper flange such that a portion of the flange extends beyond the edge. The welding step 908 may further include welding an outside surface of the lower flange to an inside surface of the second face plate such that a portion of the second face plate extends beyond the lower flange. In these embodiments, the portion of the upper flange provides a backing strip to allow a plurality of composite modular panels to be joined together. The method 900 may be used to produce a composite modular panel as described above.

Embodiments of the present invention provide several advantages over the prior art. Using the modular panel assemblies, a modular panel can be quickly assembled on site, and sized and configured as desired. By varying the thickness of the face plates and the core, an easily produced modular panel providing desired shear characteristics is obtained. The prefabricated panel assemblies, including the core layer, provide increased stiffness for transportation and assembly. The prefabricated panel assemblies without the core layer allow for reduced weight during transport. The core material may be added at the user site as desired.

Embodiments of the present invention provide modular panel assemblies that are easier to fabricate than prior art panels. The embodiments are much less dependent on the availability of special welding equipment. Some embodiments may also be fabricated at the construction site, thus providing a significant cost savings. Additionally, the embodiments effectively prevent the complete disengagement of the shear connectors which may lead to total separation of the face plates.

It will be appreciated by a person skilled in the art that numerous variations and/or modifications may be made to the present invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects to be illustrative and not restrictive.