Patent Application
20100031586
Embodiments of the present invention relate to a roof joist for a modular building.
Modular buildings are often made from pre-fabricated, portable building elements that are designed to facilitate shipment and assembly of a building structure at a building site. Modular buildings can also be transported in large preassembled sections and then connected at the building site. Such buildings reduce fabrication and assembly costs by allowing mass production and partial assembly of common parts and sections of buildings. They can also be rapidly deployed to replace damaged buildings after natural disasters, such as hurricanes and earthquakes. As such, modular building structures have unique design requirements which are different from conventional buildings. For example, modular buildings can be designed to allow flexible configurations for different types of external configurations and interior spaces. They can also be designed facilitate ease of assembly onsite and at a building location. Further, when used in disaster zones, replacement modular buildings often have to meet strict regional standards with respect to seismic resistance and storm-resistant structural frame.
The structural components and other parts for such modular building also have unique requirements. For example, the modular building components need to be designed to facilitate mass production and transport. Component shape standardization can also be used to reduce warehouse storage space required to keep a large number of prefabricated components. Further, modular parts should also be adaptable to allow for a wide variety of end use applications. In addition, it is desirable for a modular components to be adapted for multiple uses to reduce the number of components used in each building.
One component type that needs special attention in such building structures is the roof joist. A roof joist provides load-bearing capabilities to support the roof structure and resist shearing forces. A number of different types of roof joists have been used in building construction, including, for example, a simple I-beam structure made from structural steel. In some embodiments, roof joists are parallel beams made of timber, steel, or reinforced concrete beams, and are shaped and sized to support the roof of the building. However, many such embodiments of roof joists are heavy and difficult to transport or even to fabricate. They also have different, non-standardized designs that are not always readily adaptable to meet the standards of different building designs.
For reasons including these and other deficiencies, and despite the development of various roof joist structures and modular buildings, further improvements in roof joists and such buildings are continuously being sought.
A roof joist can be used in a roof section of a modular building comprising an interior ceiling having a length. The roof joist comprises an upper chord comprising a length sufficiently long to extend substantially across the entire length of the interior ceiling of the roof section of the modular building. A central chord is joined to the upper chord. A lower chord is joined to the central chord. The lower chord comprises: (i) a top chord segment; (ii) first and second sidewall chord segments that extend downwardly from the top chord segment and oppose one another; and (iii) first and second outer flanges that extend outwardly from the first and second sidewall chord segments, respectively, the flanges being capable of supporting the interior ceiling.
A method of forming the roof joist comprises: (a) extruding a material to form an extrusion preform comprising an upper chord, a central chord joined to the upper chord, and a lower chord joined to the central chord, the lower chord comprising: (i) a top chord segment; (ii) first and second sidewall chord segments that extend downwardly from the top chord segment and oppose one another; and (iii) first and second outer flanges that extend outwardly from the first and second sidewall chord segments, respectively, the flanges being capable of supporting the interior ceiling; and (b) cutting the extrusion preform when the lengths of the upper, central and lower chords are each sufficiently long to extend substantially across the entire length of the interior ceiling of the roof section of the modular building.
These features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, which illustrate examples of the invention. However, it is to be understood that each of the features can be used in the invention in general—not merely in the context of the particular drawings—and the invention includes any combination of these features, where:
An exemplary embodiment of a roof joist 20 for use in a roof section 24 of a modular building is shown in
The upper chord 30 has a longitudinal segment 36 with a length sufficiently long to extend across substantially across the entire length of an interior ceiling 28 of the modular building 100. In one version, the upper chord 30 comprises a longitudinal segment 36 comprising a planar beam 38. The geometry of the planar beam 38 facilitates welding or fastening the roof joist 20 in-place to a roof structure. For example, a set of fasteners 40 comprising screws, nails or clips can be used to fasten the longitudinal segment 36 to a decking product 71, or to roof panels, roof panel brackets or even drainage channels.
The central chord 34 is joined to, and parallel with, the upper chord 30. In one version, as shown in
The lower chord 32 comprises a top chord segment 48 which is also joined to, and parallel with, the central chord 34. The top chord segment 48 can also extend across substantially the entire length of the interior ceiling 28 of the modular building 100. The lower chord 32 further comprises a pair of sidewall chord segments 50a,b that oppose one another and extend parallel to the top chord segment 48. In one version, the lower chord 32 forms a U-shaped longitudinal channel 52 with its opening facing downward. In one version, the U-shaped channel 52 is rectangular, and has a depth of from about 2 to about 4 cm and a width of from about 4 to about 8 cm.
Each sidewall chord segment 50a,b of the lower chord 32 supports an outer flange 54a,b that extends outwardly from the sidewall chord segments 50a,b. In one version, the outer flanges 54a,b extend outwardly from the lower edge of the sidewall chord segments 50a,b to serve as outwardly protruding load bearing surfaces. In one example, the outer flanges 54a,b of the lower chord 32 are used to support a plurality of ceiling panels 76 which form an interior false ceiling 28 of the modular building 100 (see also
The sidewalls of the lower chord 32 can also have inner flanges 58a,b that extend inwardly from the sidewall cord segments 50a,b. The pair of inner flanges 58a,b serve as support members to support fixtures 59, such as equipment and objects used in the interior of the building. For example, the inner flanges 58a,b can be used to support fixtures 59 such as for example windows, sidewall panels, screens or even doors. In one version, the inner flanges 58a,b extend inward from the sidewalls by between about ⅛ to about ⅓ of the diameter of the U-shaped channel 52 as defined by the lower chord 32. The channel 52 with inner flanges 58a,b can also provide a location for universal attachment of user equipment, such as, for example, lighting, white boards or projection screens without the need for drilling, screwing or nailing into the structure. In one version, each inner flange 58a,b of the lower chord 32 has a length which is sized smaller than a length of each outer flange 54a,b. In one version, each inner flange 58a,b comprises a length of from about 1 to about 3 cm, or even about 2 cm. This length is suitable for providing load-bearing support surface for sidewall panels or other support-tab-equipped fixtures.
In another embodiment, as shown in
The first and second longitudinal hollow channels 60a,b serve as reinforcing structural members that allow the roof joist 20 to accommodate the structural load of the ceiling with a minimal of structural material and weight. This structure decreases the weight of each roof joist 20 and the lower weight also facilitates transportation of the joists. The hollow longitudinal channels 60a,b also have dual function in that, in addition to serving as a support for roof and ceiling panels, they also provide an enclosed hollow leakage-containing structure to retain moisture seepage from the ceiling or sidewalls without allowing permeation of this moisture into the building. For example, fasteners such as screws or clips can be attached into or even through the longitudinal segment of the joist 20 without risk of leakage into the building. The sidewalls of the second hollow channel 60b can be drilled and fastened to provide support points for wires or electrical connections, plumbing, ventilation or other utilities while substantially reducing risk of moisture seepage from the first hollow channel 60a.
In one version, the second enclosed volume 62b is sized larger than the first enclosed volume 62a. For example, the second enclosed volume can be at least 1.5 times larger than the first enclosed volume. A ratio of 1.5 provides a reduced region for external water containment which can subject the beam to a greater structural load. In addition, the ratio of the first and second volumes serves to provide a selectively larger region for the fastening of internal or external components to the joist 20. For example, increasing the volume ratio from 3:2 to a volume ratio of 4:1 allows a greater surface area for drilling and fastening of interior components to the joist 20.
In still another version, as shown in
The inner flanges 58a,b can have a shaped surface to reduce accidental slippage of load-bearing support tab 78. In one version, each of the inner flanges 58a,b are equipped with an inner ridge 82a,b, respectively. In this version, the inner ridges 82a,b can, for example, extend upward from the load-bearing surface by a distance of from about 0.1 to about 0.5 cm. As shown, the inner ridges 82a,b can have a cross-sectional profile that is triangular (as shown in
Alternatively, the load-bearing upper surface of each inner flange 58a,b and the downwardly facing surface of the support tab 78 can be shaped to mate together as shown in
The roof joist 20 can be fabricated by a number of different methods. In one version, the roof joists 20 comprise a shaped extruded structure which has a consistent cross-sectional shape throughout its length. In this method, the roof joist 20 is formed by extruding a material to form an extrusion preform comprising upper chord 30, a central chord 34 joined to the upper chord 30, and a lower chord 32 joined to the central chord 34, the lower chord 32 comprising: (i) a top chord segment; (ii) first and second sidewall chord segments 50a,b that extend downwardly from the top chord segment 48 and oppose one another; and (iii) first and second outer flanges 54a,b that extend outwardly from the first and second sidewall chord segments 50a,b, respectively, the flanges being capable of supporting the interior ceiling 28. The extrusion preform is cut when the length of the upper, central and lower chords 30, 34, 32 are each sufficiently long to extend substantially across the entire length of the interior ceiling 28 of the roof section 24 of the modular building 100. However, it should be noted that the roof joist 20 can also be made by other non-extrusion methods, for example: cutting and welding of metal tube and sheet stock, bending and welding of multiple formed parts, and pultrusion, as would be apparent to those of ordinary skill in the art.
The roof joist 20 can be made from a metal, including steel, aluminum, iron, tin, or alloys thereof. The roof joist 20 can also be made from a polymer or composite material. In one example, the roof joist 20 is made from extruded aluminum which is lightweight, strong and relatively flexible. The roof joist 20 can also be made from a reinforced composite material, such as carbon or polyimide fibers in an epoxy matrix.
The roof joist 20 can be used in any building, including a modular building 100 that is rapidly deployable, easily transportable, and which is designed to minimize on-site assembly, as shown in
The roof joist 20 supports a roof 26 which can be a variety of different structures. For example, a decking product 71 can be attached to the top of a roof joist 20 to form a rigid surface that supports a roof section 24, as shown in
Alternately, the roof 26 can comprise roof panels 70 that are fastened directly to the longitudinal segments 36 of the roof joists 20 or that are fastened to the joists 20 through intermediary roof panel brackets 72. An embodiment of a roof structure having intermediary roof panel brackets 72 and roof panels 70 is shown in
The roof joists 20 and roof 26 are used to cover the structural frame of a modular building 100 as shown in
Floor joists 132 extend across the upper surface of the sled 102 to provide a floor having structural rigidity and without seams. The floor joists 132 can comprise conventional tubular sections or beams. A raised floor 134 is formed from floor panels 136 placed between the framework of the floor joists 132 to provide the necessary structural diaphragm for the base of the shed 104. As one example, the floor panels 136 can be made from structural metal decking. As another example, the floor panels 136 can be composed of concrete-filled metal pans that sit on pedestals so that the underlying cavity can house electrical and mechanical services. The floor panels 136 can also be rearranged to move outlets, ports, and air diffusers, providing the user with maximum flexibility. The under-floor distribution of mechanical services for the overlying shed 104 can include HVAC (heating, ventilation and cooling) tubes, electrical junction boxes and preassembled wiring. Locating electrical and mechanical services underneath the floor 134 of the shed 104 provides an integrated infrastructure for such services and can be tailored without extensive pre-wiring and ventilation planning for the overlying shed 104.
The shed 104 placed on the sled 102 comprises a steel framework of spaced-apart columns that are linked to one another by overhead roof joists 20 and trusses 110, as shown in
The minor columns 116 can be spaced apart a sufficient distance to accommodate wall panels, such as light-impermeable panes 186, light-permeable panes 188, such as windows, translucent screens or even doors. Advantageously positioning the minor columns 116 a predefined spacing distance provides a highly adaptable exterior sidewall for the shed 104, so that each exterior sidewall can be adapted to allow the transmission of light, serve as an opaque wall, or even provide an integrated connection of the interior space of the shed 104 to other structures, such as an expansion module 106. The structure of the shed 104 also enables the two long exterior sidewalls to be absent—structural reinforcements which are conventionally needed to provide strength in seismic or storm locations—consequently enabling the shed 104 to have a variety of different external wall configurations.
The expansion module 106 comprises a steel frame designed to be attached to an open sidewall or end wall of a shed 104 to expand the usable enclosed space provided by the shed 104. For example, the expansion module 106 can comprise major columns 114 that form the corners of its structural frame, at least two of the columns being external to the shed 104 and two other columns being integrated into a sidewall of the shed 104. The expansion module 106 also has a sidewall with minor columns 116 that can be spaced apart as described in the minor columns of the shed 104 to allow spaces for light-permeable panes 188, doors, or other structures. A single wide-flange beam 126 bolted to a concrete grade beam 124 can be used to support the outside sidewall of the expansion module 106. The expansion modules shown in
The ceiling or roof plane of the modular building 100 can have variable heights and provide optional clerestory natural lighting. As a result, the modular building 100 can be tailored to a wide range of interior environments while still providing a quick-to-deploy modular building that is safe and long-lasting. For example, the shed 104 can comprise a roof 26 comprising a tilted support structure 122 that can be equipped with clerestory windows along the triangular gap between the roof plane and the shed sidewall, as shown in
The roof structure comprises trusses 110 that rest on and are anchored to the steel frame of the underlying shed 104 or the frame of the expansion module 106. The trusses 110 can be steel or aluminum beams or even composite support beams. The trusses are equipped with attachment surfaces 112 for fastening of roof joists 20, which span the length between trusses 110, as shown schematically in
The ceiling 220 of the expansion module 106 can be an open ceiling or an enclosed ceiling formed by ceiling joists 20. The ceiling joists 20 are spaced apart a set distance of 4 feet, for example, and linked at their ends to the ceiling beams which are connected to one another and the major and minor columns 114, 116. The structure provides a rigid framework which also allows easy expansion of the interior space provided by the shed 104 while providing good structural strength.
Each of the sled 102, shed 104, and expansion modules 106 comprise a structural frame of modular building components, and they are transported onto a building site with essentially all labor-intensive and inspection-intensive work—such as welding, drilling and cutting—already completed. This allows a modular building 100 composed of the sled 102, shed 104, and optional expansion modules 106 to be quickly assembled on the site to provide a fully integrated housing structure. The pre-manufactured structural components comprise a “kit of parts” that only need to be joined or partially assembled without extensive onsite alterations to provide a high performance structure with an adaptable interior configuration. The structures also reduce risks associated with improper assembly by requiring only minimal skill levels for assembly and equipment usage. The assembled modular building 100 can also withstand the vertical and lateral forces generated in earthquakes and storms. Further, the structures also reduce or eliminate onsite construction waste as leftover materials remain at the factory for recycling.
An exemplary embodiment of a modular building 100 is shown in
The modular building 100 can be customized to include additional components. For example, a handicapped access ramp 135 comprising a rigid tilted surface 137 and handrails 138 can be provided at an entrance to the shed 104. The access ramp 134 can be configured to allow passage of wheeled devices, such as wheelchairs and strollers, from ground level outside of the modular building 100 to the interior of the shed 104. A sun shade structure such as awning 142 can be provided to filter or even block direct sunlight to some or all of the side panels of the modular building 100. Solar panels 140 can be mounted on or even integrated into the roof structure or can be supported on peripheral structures such as awning 142. Finally, a green roofing material 144 capable of filtering pollutants from the surrounding air can be provided for example, a layer of plants.
While illustrative embodiments of roof joist 20 are described in the present application, it should be understood that other embodiments are also possible. For example, the roof joist 20 can have other shapes and structures and can be made from other materials, as would be apparent to those of ordinary skill in the art. Thus, the scope of the claims should not be limited to the illustrative embodiments described herein.
This application claims the benefit of provisional application No. 61/060,399 filed Jun. 10, 2008, which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61060399 | Jun 2008 | US |
