The present invention relates to light metal frame structures and more particularly to a composite metal and concrete deck that forms a part of a floor system.
Composite metal and concrete deck floor systems are known. These composite structures include a metal deck and a concrete slab supported on the metal deck. More particularly, one type of composite deck system comprises a concrete slab which is reinforced and supported by a cold formed steel deck. These two basic components work together to provide superior load carrying capability. The metal deck material is of a uniform thickness. In some traditional designs, the cold formed metal deck is shaped such that there is provided a generally horizontal bottom with portions of the deck bent and shaped so as to project upwardly from the bottom. The metal deck material is of a uniform thickness. The horizontal portion of the metal deck serves as a form for the concrete. In addition, the horizontal portion of the metal deck functions as a positive reinforcement for the structural concrete slab. The upstanding portions of the metal deck that project upwardly from the bottom also adds load carrying capacity to the deck assembly.
There are generally three phases to the construction of such a deck. First the metal decking is laid down over supports. Sometimes intermediate and temporary supports may be required. The decking must support itself and also the personnel and equipment needed to install it. As noted above, in some conventional metal decks for flooring, there is provided upstanding structures formed in the metal itself. The tops of these upstanding structures are generally in compression while the horizontal or bottom portions of the deck are in tension. It is well recognized that steel is most efficient when in tension. Next, concrete is poured onto the metal deck. There is no composite action yet, so the metal deck must now support the added weight of the concrete. In the third phase, the concrete hardens and the composite action takes place between the metal decking and the concrete. The top of the concrete slab is in compression which, as is well known, is where concrete is most efficient. As one looks down through the concrete, more tension forces are experienced and the further down in the concrete, the weaker the concrete becomes. The steel portion or the metal deck portion now comes into play and provides additional tensile strength to the assembly.
There are several limitations or disadvantages to such a conventional composite metal-concrete deck floor. First there is a tradeoff in decking metal thickness. A heavier gauge metal is unnecessary in the bottom or horizontal portion of the metal deck but would add load carrying capacity to the assembly in the structural portions of the deck that project upwardly from the horizontal or bottom portions, especially where the steel is in compression. Conversely, a lighter gauge metal would save on material in the horizontal portion of the metal deck. But this would reduce the load capacity where the steel is in compression.
In addition when a load is applied to a composite metal-concrete deck in a horizontal direction, as may be experienced in a progressive collapse condition or extreme loading event, the decking is subject to spreading apart in the horizontal direction. This could result in a failure of the entire floor system. This is due to the poor tensile strength of concrete and the fact that the metal deck typically does not provide reinforcement that resists such loads.
The present invention relates to a composite metal-concrete floor used in buildings wherein the composite comprises a multi-piece assembly. Specifically the multi-piece assembly comprises a plurality of deck pans and one or more stiffening connectors that connect the deck pans together. The deck pans are constructed of a relatively light gauge metal while the stiffening connector which adds to the load carrying capacity of the composite is made from a relatively heavier gauge metal.
In one particular embodiment, the present invention entails a deck pan assembly having multiple gauge metal components for receiving concrete. The deck pan assembly includes a series of metal deck pans and at least one stiffening connector for connecting two of the deck pans together. The deck pans are formed from sheet metal having a first thickness while the stiffening connector is formed of sheet metal having a second thickness which is greater than the first thickness. Expressed in another way, the sheet metal that forms the deck pans is of a relatively light gauge while the sheet metal that forms the stiffening connector is of a relatively heavy gauge.
Other objects and advantages of the present invention will become apparent and obvious from a study of the following description and the accompanying drawings which are merely illustrative of such invention.
With further reference to the drawings, a composite floor deck is shown and indicated generally by the numeral 100. Composite floor deck 100 is made up of a combination of sheet metal components and concrete. The sheet metal components comprise a plurality of deck pans with each deck pan indicated generally by the numeral 10. Further the metal components include one or more metal stiffening connectors indicated generally by the numeral 20. Stiffening connector 20 is utilized to connect two deck pans 10 together. As appreciated from the drawings, once the deck pans 10 are connected via the stiffening connectors 20, a metal deck is formed for receiving and supporting concrete 54.
With reference to
An alternative design is shown in
As discussed above, the stiffening connector 20 is designed to connect two deck pans together as shown in
In the
In the embodiment illustrated in
Continuing to refer to
A series of fasteners 40 secure the stiffening connector 20 to the connecting structure of the pans 10. Various types of fasteners such as screws, rivets, or weldment can be used to connect the stiffening connector 20 to the connecting structure. In the embodiment illustrated, there is provided a series of self-tapping bolts 40 that extend transversely through the flanges 12 as well as the lower side portions 24B and 26B of the stiffening connector 20.
As noted before,
Turning to the right hand deck pan 10″, it includes a bottom or web 14″ and a flange or upturned edge 12″. On the side or edge opposite the flange 12″ is provided an inverted L-shaped flange 15.
As shown in
Flanges 12′ and 12″ of the left and right hand deck pans 10′ and 10″ can be joined and secured together in the same manner as discussed above. In the example shown in
The deck pan assembly is constructed of sheet metal components wherein the gauge or thickness of the sheet metal components varies. In this design, the deck pans 10, 10′ and 10″ are constructed of a relatively light gauge sheet metal, for example 20 gauge sheet metal. The stiffening connectors 20 on the other hand are constructed of a relatively heavy gauge sheet metal, a sheet metal having a thickness greater than the thickness of the sheet metal employed for the deck pans. The increased thickness for the stiffening connector 20 increases the strength of the deck assembly during installation and during the wet concrete phase of construction. This is due to the increased metal thickness in the compression region of the composite deck 100. This increased strength will reduce the amount of temporary mid-span supports required, which are costly to erect and disassemble. After the concrete sets, the thicker material in the stiffening connectors 20 serves to further enhance the deck strength.
In addition, the strength provided by the elongated stiffening connectors 20 tends to prevent the deck pan assembly from spreading outwardly in the X direction as viewed in
There are numerous advantages to the composite deck described above. First it is a cost effective approach to a composite floor deck design. At the same time this approach optimizes the strength of the deck by selectively placing heavy gauge metal in locations where needed and not employing heavy gauge metal in places where it is not needed.
The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
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