A floor-ceiling assembly is provided for joined upper and lower modular construction units, including a floor surface of the upper unit using structural cement panels; a floor grid including at least one floor joist and at least one beam each having an upper surface receiving said structural cement panels, a web and a lower surface. At least one connector plate is secured to the lower surface. A ceiling framework of the lower unit has at least one ceiling beam and at least one ceiling joist secured to each other, at least one of the beams is secured to the at least one connector plate. A resilient channel is secured to an underside of the ceiling framework, and a ceiling panel is secured to the resilient channel.

BACKGROUND

The present invention relates generally to modular construction techniques for erecting multi-story residences, and more specifically to an improved floor/ceiling construction for such modules having an enhanced fire rating.

It is a growing trend to construct multi-story residential buildings, including hotels, apartments, dormitories, classrooms, restaurants and the like using modular units, especially in crowded urban areas where heavy construction equipment has difficulty maneuvering. Modular construction reduces material waste, and since the units are assembled indoors at remote locations, labor costs and working conditions are more closely controlled. Such modules are remotely constructed and assembled, trucked to the building site, then placed in position using a crane. Many modules are as long as 75 feet and are assembled by stacking vertically, side-by-side, end-to-end, thus providing a variety of configurations of the final building design.

Each module has a steel frame including beams and joists, and depending on the application represents one or two apartment units. Walls are conventionally assembled with studs and panels, and windows are installed in the stud frames in a conventional manner. Designers of such modules need to take into account that the ceiling of a lower module becomes part of the floor/ceiling assembly when combined with the floor of the next higher module. In many cases, the floors of the modules are poured concrete having a weight as much as 40 pounds per square foot (psf) and a 3-inch thick layer. One drawback of conventional modules is the weight, of which the poured concrete floor is a significant contributor. Heavier modules are more expensive to ship by truck to the site, and are more difficult to raise into position. Also, the design of conventional modules is constrained due to a significant amount of module height being allotted to the junction of two adjacent vertically stacked units.

Thus, there is a need for an improved modular building unit which addresses the drawbacks listed above.

SUMMARY

The above-listed needs are met or exceeded by the present two-hour fire-rated modular floor/ceiling assembly, which features the use of structural cement panels forming the floor surface. These panels have been found to be significantly lighter than conventional concrete floors, but with sufficient strength for the application. Further, the use of structural cement panels in the floor surface, along with the steel frame, has been found to pass an industry accepted two-hour fire rating. (UL 263, and ASTM E119). The present modular assembly also is vertically thinner compared to conventional modules constructed according to UL G588 or similar, allowing for taller ceilings in the module, or providing for more vertical floors within a given total building height.

Using the structural cement panels for the floor surface, the weight of the present module is significantly reduced, since the present panels have a weight of 5 psf as compared to 40 psf of poured concrete floors. The floor surface has a height of a minimum of ¾ inch, as compared to a 3-inch height/thickness of poured concrete floors. Heights of the present floor/ceiling assembly range from a minimum of 12⅝ inches to 16 inches. The present floor/ceiling assembly is achieved by using the ¾-inch thick structural cement floor panel, which is secured to an upper flange of a steel support, preferably a joist or beam having a 6-inch height. Connections between vertically adjacent units are achieved with a steel plate that is a minimum ¾-inch thick. Insulation, such as bats of fiberglass are placed in a space defined between the joists of the floor grid, below the floor panel.

In the ceiling of the lower unit, the steel frame forms a ceiling framework including preferably 4-inch tall beams and joists which is in registry with the floor grid of the upper unit. The ceiling framework of 4-inch beams and joists is provided, extending linearly and transversely relative to the unit. Junctions between beams and joists forming the ceiling support are formed by conventional 4-inch clip angles, also referred to as angle brackets. Resilient channels are secured to undersides of the ceiling joists, and conventional ⅝-inch gypsum wallboard panels are secured to the resilient channels as is known in the art. The panels form the ceiling of the lower modular unit.

More specifically, the present invention provides a floor-ceiling assembly for joined upper and lower modular construction units, including a floor surface of the upper unit using structural cement panels; a floor grid including at least one floor joist and at least one beam each having an upper surface receiving said structural cement panels, a web and a lower surface. At least one connector plate is secured to the lower surface. A ceiling framework of the lower unit has at least one ceiling beam and at least one ceiling joist secured to each other, at least one of the beams is secured to the at least one connector plate. A resilient channel is secured to an underside of the ceiling framework, and a ceiling panel is secured to the resilient channel.

DETAILED DESCRIPTION

Referring now toFIGS. 1 and 2, a multi-story building incorporating the present modules is generally designated10, and includes a plurality of joined module units12. Each module unit12includes a plurality of exterior wall panels14, doors15and windows16. The wall panels14are preferably made of structural cement, according to U.S. Pat. Nos. 7,445,738 and 7,670,520 which are incorporated by reference, however other exterior construction panels are contemplated. A ceiling18of a lower unit12L becomes part of a floor19of an upper unit12U. For the purposes of the present application, the joined floor/ceiling assembly represented by vertically joined units12U and12L is generally designated20. Naturally, as the building10is provided with multiple stories, an upper module12U of one floor/ceiling assembly will serve as the lower module12L of the next higher story.

Referring now toFIGS. 3 and 4, the floor/ceiling assembly20is described in greater detail. A feature of the present assembly20is that the floor19has a floor surface made of panels22of structural cement, sold by United States Gypsum Co. as Structural Panel Concrete Subfloor, also sold under the trademark STRUCTO-CRETE® panels, and is preferably made according to at least one of the above-listed US Patents. In the preferred embodiment, the panels22are a minimum ¾-inch thick or tall, with tongue and groove formations on the long edges. A thickness of ¾ inch to 1-inch is preferably contemplated. In the assembly20, the panels22are secured to an upper flange24or upper beam surface of at least one and preferably a plurality of floor beams26, which are conventional “I”-beams including a lower flange28or lower beam surface, the flanges separated by a web30as is well known in the art, with other shapes contemplated including tubes. In the preferred embodiment, the beam26has a minimum height of 6 inches, and is preferably 50 Ksi grade steel, however other sizes are contemplated depending on the application. A long edge of the panels22is preferably perpendicular to the beams26, and the panels are secured to the beam using threaded fasteners (not shown) as are well known in the art.

At least one connector plate32is secured to the lower beam surface28, preferably by welding. In the preferred embodiment, while other sizes are contemplated depending on the application, the connector plate32is preferably a minimum ¾-inch thick or having that size height, and is provided in a polygonal shape dimensioned a minimum 4 inches by a minimum 4 inches. Also, the connector plate32is used to join the upper unit12U to the lower unit12L, again preferably by welding or similar permanent attachment.

A space or cavity34between the panel22and the lower beam flange28is preferably filled with at least one panel or bat of insulation36, which may be foam, fiberglass or the like, well known in the art. To retain the insulation36in place, a layer of netting38, such as wire or plastic mesh, screen or the like is secured to the floor grid23, including the beams26and the transverse joists40. The netting38is held to the floor grid23by wire wrapped around the beams26and the joists40. It is also contemplated that, as a further alternative the wire mesh38is bent and wrapped around edges of the beams26and the joists40, then secured with fasteners. In some cases, the wire mesh38is bent around and attached to the beams26and the joists40to form a basket-shape into which the insulation36is placed. Then, once the panel22is installed upon the beams26and the joists40, the insulation36is trapped in place. It is also contemplated that the beams26are connected to the transverse joists40, either “I”-shaped (40′) located at ends of the module12, or “C”-shaped40″ with upper and lower flanges40a,40band webs40c(with other shapes contemplated, including tubes), secured together to form a frame42of the module12, and are secured to each other using joist clip angles or blocks44. As is known in the art, the beams26and the transverse joists40are preferably secured to the joist clip angles44by threaded fasteners or welding, as is known in the art.

Referring now to the lower unit12U of the assembly20, a ceiling framework46includes a plurality of beams48, and at least one of the beams is secured to the connector plate32, as by welding or the like to join the units12U and12L. In the preferred embodiment, while other sizes are contemplated, the beams48are “I”-beams, preferably made of 50 Ksi steel and having a minimum height of 4 inches, including a beam upper flange50, a beam web52and a beam lower flange54. The beams48are preferably in registry with the beams26upon connection of the assembly20, and the framework46includes transverse joists56, which are preferably “I”-shaped56′ at the ends of the module12or “C”-shaped56″ (with other shapes contemplated, including tubes). The joists56have an upper flange58, a lower flange60and a web62secured to the beams48at respective ends by clip angle brackets or blocks64. As is known in the art, the beams48and the joists56are secured together to form the ceiling framework46using the clip angle brackets64and threaded fasteners or welding as is known in the art.

Referring now toFIG. 4, at least one resilient channel66is secured to an underside68of the lower flanges60of the joists56. As is known in the art, the resilient channel66is made of steel and is placed perpendicular to the respective joists56and secured thereto using threaded fasteners as is known in the art. Multiple channels66are positioned across the ceiling framework46to support the ceiling18.

In the preferred embodiment, at least one ceiling panel70is secured to the resilient channel66using fasteners as is known in the art. It is preferred that the panels70are conventional gypsum wallboard, and having a thickness of ⅝-inch.

Fire tests were performed on the assembly20under at least one of ASTM E119 and UL 263. Results showed that the assembly20met a 2-hour fire rating. In other words, the assembly20remained intact when exposed to fire for a 2-hour period.

While a particular embodiment of the present two-hour fire-rated modular floor/ceiling assembly has been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.