The present invention relates to a new and novel light gauge steel “super shear” panel. Super shear panels of the present disclosure provide an efficient vertical and lateral resistive shear panel that is light and flexible and provides excellent seismic performance as well. Because the size and shape of the shear walls is repetitive rather than custom built on the job site, fabrication efficiencies exist.
In order to fully understand the momentous technology of the Applicant's new light gauge steel “super shear” system, one must first understand the history of the steel stud, and then how those steel studs morphed into the sophisticated structural light gauge steel wall panels now in existence.
By the 1930s building codes contained specifications for hot rolled steel building components. However, standards for cold formed steel products having a width of 3/16th of an inch or less (i.e., light gauge steel) were not adopted until 1946. The cold formed steel process turns light gauge sheet steel into shapes and sizes which mimic dimensional lumber (e.g., 2×4s, 2×6s, etc.). Light gauge steel framing members such as studs (i.e., an upright support in the wall of a building to which sheathing or drywall is attached) were formed in a roll forming machine by passing thin sheet steel through a series of rollers to form the bends that make the desired shape of the end product. Because this process is done without heat (hence the description “cold formed”) the studs produced are stronger than the original sheet steel.
Since the walls originally constructed by this system were not structural, they could be used only for interior building partitions and could not serve as load bearing walls. This nonstructural metal wall system quickly replaced lumber for interior partitions in buildings. Indeed, as a result of the increased construction of taller buildings in the 1950s and 1960s with life safety a paramount concern, the lightweight, non-combustible steel stud and track system increasingly replaced the conventional wood framed interior systems. (The weight of the metal stud and track system was 33% of the conventional lumber partition system.) In 2004, the Steel Framing Alliance reported that 81% of interior walls built in the U.S. used cold-formed steel framing.
As a result of improvements in the strength of the metal studs, by the 1970's building walls utilizing the stud/track system could serve as load bearing walls. Thus, these structural light gauge wall systems could be used for exterior building walls. In the 1980's, wall panel fabricators started purchasing studs and tracks and fabricating them into structural wall panels which were then transported directly to a job site. By using these prefabricated wall panels produced in a factory, no manual labor was required on the job site to assemble and connect the studs to the tracks.
By 2011, the use of structural light gauge wall systems had dramatically expanded and had surpassed the steel used to manufacture nonstructural framing. Also, the non-combustibility and termite resistance of these light gauge wall panels lowered construction and ownership costs. Presently, between 30% and 35% of all nonresidential buildings in the U.S. are built with cold-formed steel structural and nonstructural framing
While light gauge steel wall panels have been in existence for many years, until recently a roll forming machine was unable to produce large numbers of light gauge steel wall panel components which would conform to a buildings architectural layout (e.g., stud spacing requirements). The reason for this was the time consuming process of manually programming the controllers on the roll forming machines to produce the pre-engineered parts for the wall panels. Computer aided design software (i.e., CAD software) has long been used to model complex building designs with complex framing components. However, until about 10 years ago it was not possible to download these CAD models to the controller software (CNC software) embedded on the roll forming machines. At that point significant improvements were made in the automated generation of CNC software instructions from CAD building software models. Thus, large and complex building designs with thousands of unique framing components could be digitized quickly and extremely accurate sets of CNC instructions to the roll forming machines were generated automatically. This automated process integrating building design and roll forming manufacturing of the components of differing wall panels moved the light gauge cold formed steel manufacturing industry past the laborious and mistake-ridden manual programing process previously faced by the industry.
Accordingly, over the last five years several wall panel manufacturers have integrated the automated generation of CNC instructions, highly customized roll forming machines, and specific project and planning implementation resulting in the efficient large scale production of customized prefabricated wall panels. In short, the current state of the art for customized light gauge wall panels is robust and healthy.
Panelization refers to any technique by which certain types of projects can be divided into smaller assemblies for fabrication in a plant, and then installed in sections, or panels, later on the jobsite. This technique contrasts with a stick-built technique, which is the common method of framing a structure one stud, or “stick”, at a time.
Panelized construction largely focuses on the vertical walls, as these components are relatively easy to divide into panels. However, most work in a project cannot be panelized. When trades other than framing follow this process, it is more commonly referred to as modularized rather than panelized. Even more recently, the term modularized has come to refer to pre-assembly of entire rooms or sections of rooms in a plant, to include the mechanical, electrical, plumbing, and finishes.
Not all projects are ideally suited for panelization. Projects ideally suited for panelization are repetitious in alignment from floor to floor, and generally have a simple design on the exterior. The repetition in the layout of the floor plan from floor to floor is critical since alignment of walls vertically up through the structure is an inherent need of a light gauge framing system (true whether panelized or stick built). Hotels, student housing, and apartment/multi-family projects are the ideal project types for panelization. Assisted living facilities are still able to be panelized but are less ideal as a project type than the previous three described. Assisted living facilities have challenges to panelization in their designs. Specifically, large, open areas for amenities such as dining, community rooms, and lobbies are particularly challenging for panelization due to the long spans between walls. Additionally, assisted living facilities often have ornate, widely varying exterior wall designs, complex roof designs, and arched windows. These elements are commonly used in the design of these facilities to mimic the look of high end residential projects. This often creates many unique framing elements on the exterior of these facilities which are much more labor intensive to design, fabricate, and ship.
From a structural perspective, every building design must pass design criteria comprising the same basic set of design loads including gravity loads, lateral loads and seismic loads, all described below.
Gravity Loads may also be referred to as axial loads because the load is born along the long vertical axis of the studs). A dead load refers to the weight of the building and its contents without people in the building while a live load refers to not only the weight of the building and its contents but the weight with people inside the building.
Lateral loads are loads on the building from wind. The Engineer of Record (“EoR”) on the project determines what wind speeds to design for based on weather criteria for the region. Those wind speeds are converted into a force in pounds per square foot, and each design must contain a Lateral Design System to deal with those forces. The Lateral Design System is a combination of vertical elements “shear walls” and the horizontal floor elements “diaphragm”. Each of these two elements work in concert with each other to brace the building against the wind. The lateral design system can vary a lot from building to building, and it can become quite complex when designed in conjunction with seismic loads.
Seismic loads are loads on the building due to an earthquake. The EoR designates the seismic requirements based on the Seismic Zone in which the building is located. Seismic zones are ranked from 1-4, with 4 being the most susceptible seismic areas. Many areas in the west coast are in Seismic Zone 4. Unlike wind loads which blow in one direction at a time, seismic loads are eccentric in nature. A seismic reaction can cause the building to move in all directions, unpredictably, and repeatedly. While wind load can be resisted with “brute force”, such as large reinforced masonry shafts around the stairs and elevators, this is directly counterproductive to seismic design. Seismic design requires the building to be light and flexible, i.e. bend but don't break. Efficient systems for lateral resistance, such as masonry, are far too rigid, brittle, and heavy to be effective in a seismic design.
The following presents a simplified summary of one or more implementations in order to provide a basic understanding of some implementations. This summary is not an extensive overview of all contemplated implementations, and is intended to neither identify key or critical elements of all implementations nor delineate the scope of any or all implementations. Its sole purpose is to present some concepts of one or more implementations in a simplified form as a prelude to the more detailed description that is presented later.
According to one feature, a structural support for a shear panel is provided. The structural support comprises a pair of assembled frames where each assembled frame in the pair of assembled frames comprises an inner frame comprising a pair of vertical member integrally connected to a pair of horizontal members forming the inner frame; a first inverted stud connected to and extending between the pair of horizontal members of the inner frame, the first inverted stud having a first open face; a second inverted stud connected to and extending between the pair of horizontal members of the inner frame, the second inverted stud having a second open face; and a third inverted stud connected to and extending between the pair of horizontal members of the inner frame, the third inverted stud having a third open face, where the second inverted stud is located between and equidistant from the first and third inverted studs.
The pair of assembled frames are integrally connected such that the open faces of each of the first, second and third inverted studs of a first assembled frame in the pair of assembled frames are connected to open faces of the first, second and third inverted studs of a second assembled frame forming first, second and third inverted stud assemblies; and the connection of the open faces of each of the first inverted studs of the first inverted stud in the first and second assembled frames form a first hollow square tube.
According to one aspect, the connection of the open faces of each of the second inverted studs of the second inverted stud assembly in the first and second assembled frames form a second hollow square tube.
According to another aspect, the connection of the open faces of each of the third inverted studs of the third inverted stud assembly in the first and second assembled frames form a third hollow square tube.
According to yet another aspect, structural support further comprises a first outer boundary column integrally connected to the integrally connected pair of assembled frames along a first vertical edge.
According to yet another aspect, the structural support further comprises a second outer boundary column integrally connected to the integrally connected pair of assembled frames along a second vertical edge.
According to yet another aspect, wherein each of the first, second and third inverted studs comprise a pair of vertical wall members integrally connected perpendicularly to a web and a first return integrally connected to and extending outwardly from a first vertical wall member and a second return integrally connected to and extending outwardly from a second vertical wall member.
According to yet another aspect, wherein a piece of sheet metal is located between the pair of assembled frames.
According to yet another aspect, the structural support further comprises a top track encompassing the pair of assembled frames and the first and the second outer boundary columns
According to yet another aspect, the structural support further comprises a bottom track encompassing the pair of assembled frames and the first and the second outer boundary columns, the bottom track is parallel to the top track.
According to yet another aspect, the first outer boundary column is embedded within the foundation of a structure.
According to yet another aspect, the second outer boundary column is embedded within the foundation of a structure.
According to yet another aspect, wherein the open faces of each of the first, second and third inverted studs from the first assembly are fastened to the open faces of each of the first, second and third inverted studs from the second inverted stud assembly by screws.
According to yet another aspect, wherein the open faces of each of the first, second and third inverted studs from the first assembly are fastened to the open faces of each of the first, second and third inverted studs from the second assembly by welding forming first, second and third inverted stud assemblies.
According to another features, structural support for a shear panel is provided. The structure support comprises a pair of assembled frames, a first outer boundary column integrally connected to the integrally connected pair of assembled frames and a first vertical edge; and a second outer boundary column integrally connected to the integrally connected pair of assembled frames along a second vertical edge of the pair of assembled frames.
Each of assembled frames in the pair of assembled frames comprises an inner frame comprising a pair of vertical member integrally connected to a pair of horizontal members forming the inner frame; a first inverted stud connected to and extending between the pair of horizontal members of the inner frame, the first inverted stud having a first open face; a second inverted stud connected to and extending between the pair of horizontal members of the inner frame, the second inverted stud having a second open face; and a third inverted stud connected to and extending between the pair of horizontal members of the inner frame, the third inverted stud having a third open face, where the second inverted stud is located between and equidistant from the first and third inverted studs.
The pair of assembled frames are integrally connected such that the open faces of each of the first, second and third inverted studs of a first assembled frame in the pair of assembled frames are connected to open faces of the first, second and third inverted studs of a second assembled frame forming first, second and third inverted stud assemblies; and the connection of the open faces of each of the first inverted studs of the first inverted stud in the first and second assembled frames form a first hollow square tube.
According to one aspect, each of the first, second and third inverted studs comprise a pair of vertical wall members integrally connected perpendicularly to a web and a first return integrally connected to and extending outwardly from a first vertical wall member and a second return integrally connected to and extending outwardly from a second vertical wall member.
According to yet another aspect, a piece of sheet metal is located between the pair of assembled frames.
According to yet another aspect, the structural support further comprises a top track encompassing the pair of assembled frames and the first and the second outer boundary columns
According to yet another aspect, the structural support further comprises a bottom track encompassing the pair of assembled frames and the first and the second outer boundary columns, where the bottom track is parallel to the top track.
The features, nature, and advantages of the present aspects may become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identify correspondingly throughout.
The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
In structural engineering, a shear wall is a structural system composed normally of braced panels (also known as shear panels) to counter the effects of lateral loads acting on a structure. The Super Shear panel of the present disclosure provides an efficient lateral resistive shear panel that is light and flexible and provides excellent seismic performance as well. Because the size and shape of the shear walls is repetitive rather than custom built on the job site, fabrication efficiencies exist.
A structure of shear walls in the center of a large building (often encasing an elevator shaft or stairwell) form a shear core. As noted above, masonry shafts, while excellent for wind load lateral resistance, perform poorly in seismic design. Even the most conventional type of light gauge shear wall, comprising X braced straps tied to the perimeter of the wall panel, perform poorly in seismic design. The most favorably tested system to date is a light gauge shear wall that replaces the X brace strap with sheets of metal that cover the entire face of the wall. Super Shear also uses sheet metal and light gauge framing to ensure the walls are light and flexible.
Using Super Shear panels of the present disclosure in lieu of other slower processes, such as masonry, expedites the project schedule by eliminating concrete pouring and curing. For example, on the typical hotel that utilizes masonry shafts, those shafts are commonly built start to finish and topped out before any panel work can start. This duration can be six to eight weeks before panelization can start. By utilizing the light gauge steel “super shear” system of the present disclosure, the entire masonry scope duration can be removed from the schedule.
The Super Shear wall of the present disclosure may be the same size wall for each floor of a building. Typically, the wall will be built in eight-foot sections, and in sufficient quantities to resist the seismic and lateral loads defined above. In conventional design, the shear walls are twenty feet long on average, extremely heavy and hard to deal with in the plant. This methodology requires flipping the panel over during fabrication. Flipping a panel in fabrication is problematic, somewhat unsafe, and slow.
An eight (8) foot Super Shear panel may be used to replace what would otherwise require seven (7) vertical studs on 16 inch centers (i.e., six (6) spaces between the seven (7) studs @ sixteen (16) inches per space equals ninety-six (96) inches or eight (8) feet). Such an eight (8) foot Super Shear panel will exactly accommodate two four (4) feet by eight (8) feet, two four (4) feet by ten (10) feet or two four (4) feet by twelve (12) feet drywall sheets (with the length of the dry wall sheets being dependent based on the ceiling height).
Sheet steel type shear walls have historically involved a process of simply framing a wall, and then applying sheet steel to the entire face of the wall with screws before the drywall is installed over the sheet steel for a finished product. However, this creates several jobsite problems that the Super Shear panel seeks to solve.
First, the Super Shear panel design of the present disclosure moves the sheet steel from the outside face of the walls to the center of the wall line. This is substantial because one of the inherent weaknesses of a sheet steel system is that other trades cannot make required penetrations into the sheet steel without weakening it substantially. Since the majority of walls in a commercial structure have electrical, plumbing, or mechanical elements coursing through them, there is inevitable conflict between trades competing for the same space.
Additionally, sheet steel is not very strong in terms of pounds per square foot of force it can resist, and this weakness therefore forces the designers to use large quantities of sheet steel. It is common that 30-40% of interior partitions have some amount of sheet steel laminated to them. On the bottom floors of structures, where the loads are collecting from stories above, designers often run out of wall space on which to apply enough sheet steel to meet project shear requirements. Consequently, such situations may require sheet steel on both sides of the walls. While this solution gains enough sheet steel to do the job, it completely closes the wall cavity to installation by mechanical, electrical, and plumbing trades, and prevents access by inspectors. By moving the sheet steel to the center of the wall, all these problems are solved with Super Shear panel of the present disclosure.
The potential of super shear panels lies largely in eliminating masonry and/or concrete shafts from the project and making the entire project possible to construct using only light gauge steel panels and Super Shear panels. In doing so, it becomes substantially more efficient to produce since the Super Shear panels can be fabricated in the plant unlike other light gauge shear wall designs. While not essential to its structural performance, the accommodations provided to the other trades by the Super Shear panel configuration of the present disclosure alone will make it a preferred methodology by construction trades.
Before proceeding with the description and operation of the shear panel, it will be helpful to again review several of the attached figures.
Turning to
According to one example, the Inverted Studs 502, 504 can be joined open face to open face by screwing together the protruding returns (see
The shear panel of the present disclosure may have a constant width of 8 feet and a height of whatever clear space is required in the building's interior space, in accordance with one aspect. For a 10-foot clear ceiling height, the shear panel would be 8 ft. wide by 10 ft. high. Accordingly, the remainder of this disclosure will assume an 8 ft. wide shear panel is being fabricated for a 10 ft. high clear space.
The shear panel may be comprised of the following components: (1) inner frames; (2) studs with inverted returns (or inverted studs); (3) sheet metal; (4) boundary columns; and (5) tracks.
With respect to the inner frames, the sheer panel may have two 8 ft. by 10 ft. inner frames (an inside inner frame and an outside inner frame) of 3 inches by 2 inches of a light gauge steel angle 800 (See
With the respect to the inverted studs, the shear panel of the present disclosure may include three Inverted Studs 902, 904, 906 (See
With respect to the sheet metal, the shear panel may have sheet metal pieces 908, 910 which may be 4 ft. wide and 10 ft. long, according to one aspect, which will run vertically between the left and right four foot portion of the inside Assembled Frame and the outside Assembled Frame when the Assembled Frames are joined together.
With respect to the boundary columns 912, 914, the exterior of each shear panel may be encased by boundary columns 912, 914. This boundary columns 912, 914 may originate and be embedded in the building foundation and will proceed upward through each of the floors of the building as indicated in
With respect to the tracks, a top 916 and bottom track 918 may be used to encompass the completed bundling of the (1) inner frames; (2) studs with inverted returns (or inverted studs); (3) sheet metal and (4) boundary columns as described above.
The completed shear panel may have a six inch depth. When drywall is attached to the closed faces of the Inverted Studs (which may be on two ft. centers), the drywall attached to the completed shear panel may be on the same plane as the drywall sheets attached to the regular conventional non-shear 6 inch wall panels.
According to one aspect, the width of the shear panel may be extended in four foot increments which means that the boundary columns may be moved further apart and replaced by a joined together inverted stud assembly. The Inverted Studs, Tracks, and Steel Angles of the shear panel may utilize 12 gauge to 18 gauge light gauge steel with 14 gauge to 16 gauge most likely to be utilized. Likewise, the sheet metal used in the shear panel may range from 18 to 22 gauge with 20 gauge most likely to be utilized. The prevailing axial and shear requirements of the building will dictate the choice of the gauges to be utilized. Applicant believes that the available options to upgrade the shear and axial performances of the shear wall by increasing the shear wall length, and/or upgrading the grade of the light gauge steel and sheet metal will allow the shear panel to be the most robust in existence.
One or more of the components and functions illustrated in the previous figures may be rearranged and/or combined into a single component or embodied in several components without departing from the invention. Additional elements or components may also be added without departing from the invention.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
This application claims priority to a provisional application, U.S. Ser. No. 62/691,336, filed Jun. 28, 2018, entitled “Super Sheer Panels”.
Number | Date | Country | |
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62691336 | Jun 2018 | US |