The present invention relates generally to modular construction techniques for erecting multi-story residences, and more specifically to a modular assembly for below-grade construction for buildings.
Residential and commercial buildings need a foundation to shoulder the considerable weight of the building materials, provide a flat and level base for construction, and separate wood-based materials from contact with the ground, which would cause them to rot and be infested by termites.
Foundations are commonly constructed with concrete. First, a hole corresponding to the size of the foundation is dug in the ground to a desired depth based on the size and height of the area of the building that is below grade, such as a basement or crawl space. Once the dirt is removed, inner and outer forms made out of wood or steel, are erected along the perimeter of the building and are spaced apart based on the designated thickness of the foundation walls. After concrete is poured in the space between the inner and outer forms and sets, the inner and outer forms are removed to reveal the foundation. Next, additional forms are erected on the foundation to form the walls of the below-grade area. Installing the forms, pouring the concrete, allowing the concrete to set and then removing the forms takes several days and sometimes weeks. This adds significant time to the overall construction schedule for residential and commercial buildings as well as increases the construction costs.
It is a growing trend to construct multi-story residential buildings, 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, transported to the building site, then placed in position using a crane. Many modules are as long as 75 feet and are assembled by stacking the modules vertically, side-by-side and end-to-end, thus providing a variety of configurations of a final building design. These modules, however, are typically made of lightweight materials that are typically not structurally strong enough for the vertical, lateral and shear forces applied to the foundation and below-grade walls by the surrounding dirt and by the weight of the building materials used to construct the floor or floors built above the below-grade area.
Thus, there is a need for a modular assembly for below-grade structures of residential and commercial buildings.
The above-listed need is met or exceeded by the present modular assembly that is configured to be installed below grade and support one or more floors of a residential or commercial building. To save time and costs, the modular assembly is manufactured at a remote location and transported to a site for quick and easy installation in a below grade open area formed in the ground.
In an embodiment, a modular assembly is provided and includes a modular frame to be installed at least partially below grade and at least two panels attached to the modular frame, where the at least two panels are made of a material that withstands lateral, vertical and shear forces generated by surrounding below grade materials. The modular frame and the at least two panels are joined together as a unit prior to installation.
In another embodiment, a modular system for below-grade installation is provided and configured to support a multi-story building. The system includes at least two modular assemblies secured together as a unit, where each of the modular assemblies is configured to be installed at least partially below grade. The modular assemblies each include a modular frame and at least two panels attached to the modular frame, where the at least two panels are made of a material configured to withstand lateral, vertical and shear forces generated by surrounding below grade materials, and where the modular frame and at least two panels are joined together as a unit prior to installation.
In a further embodiment, a method of forming a modular assembly for installation below grade is provided and is configured for supporting a building, where the method includes attaching at least two panels to a modular frame at a remote location. The at least two panels are made of a material that withstands lateral, vertical and shear forces generated by surrounding below grade materials.
Referring now to
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After the outer structure of the modular frame 28 is assembled, a plurality of secondary structural supports 32, i.e., studs, are attached between the upper and lower ends of the modular frame 28 to form the walls of the modular assembly 20. The secondary structural supports 32 are preferably two inches by eight inches and a desired length but may have any suitable thicknesses, dimensions and length. Also, the secondary structural supports 32 are made of cold-formed steel, but may be made with wood or any suitable material. In an embodiment, the secondary structural supports 32 may be attached between the walls at the upper end, lower end or both the upper and lower ends of the outer structure as structural support for installing a floor, a ceiling or both a floor and ceiling on the modular assembly 20.
When the construction of the modular frame 28 is finished, a plurality of sub-grade panels 34 (
In the illustrated embodiment, the sub-grade panels 34 are made of a fiber-glass reinforced cementitious material that is non-rotting, termite-resistant, mold-resistant and moisture-resistant (change in moisture content of less than 10%). Further, the material used to form the panels 34 is stable, i.e., the panel will not buckle or warp like conventional wood sheathing, non-combustible and dimensionally stable and strong to support backfill loads of 2000 pounds per square foot and greater, and to carry shear and gravity loads. Preferably, each panel 34 is configured to support a uniform load of up to 2083 pounds per square foot when is the secondary structural supports 32 are spaced 12 inches apart and shear wall design ratings of up to 1726 pounds per linear foot. In the illustrated embodiment, the panels 34 each have a width of 4 feet and a length of 8 feet with a thickness of ¾ (0.75) inches. The panels 34 may also have a thickness of ⅝ (0.625) inches. It should be appreciated that the panels 34 may have any suitable width, length and thickness based on desired construction specifications. Additionally, each panel 34 has a weight of 5 pounds per square foot, which is significantly less than the weight of concrete walls used for conventional below-grade areas of residential and commercial buildings. The lighter weight of the panels 34 also makes transport and installation of the modular assemblies 20 easier and less expensive.
In an embodiment, the physical and mechanical properties of the sub-grade panels 34 are described in the following table:
1Fastener Lateral Resistance Measured with Applicable Fasteners
2Density Measured at Equilibrium Conditioning per Section 5.2.3.1: Tested 28 Days After Manufacturing
3Absorption Measured from Equilibrium Conditioning Followed by Emersion in Water for 48 hours
Additionally, in applications where plywood is typically used as on the exterior or interior of a wall, floor or ceiling, the sub-grade panels 34 may be used instead of plywood in accordance with the ANSI PWF-Specification and the CAN CSA S406 Specification.
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Typically, openings and holes are formed in structural below grade or sub-grade walls to enable water pipes, electrical pipes or other structures to extend through the walls. In conventional concrete walls, such openings and holes must be cut after the concrete has set. The cutting of the concrete walls requires a concrete blade and/or drill bit and generates a significant amount of dust that is hazardous to the person cutting the walls and also creates a lot of dust. The panels of the present modular assembly 20 are made to withstand the shear, lateral and vertical loads from the surrounding ground materials used as backfill, such as dirt, rock and gravel, and above grade construction while enabling conventional blades and drill bits, such as carbide-tipped blades and bits, to be used to cut openings and holes in the panels. In this way, the panels 34 of the below-grade modular assembly 20 are much easier to cut and generate significantly less dust.
Referring to
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While particular embodiments of the present modular assembly have 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.
Number | Date | Country | |
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62755418 | Nov 2018 | US |