Abstract:
A framed shear wall has a pair of crossed tension straps passing through the studs that make up the shear wall. The straps are preferably rods and are preferably attached to upstanding plates installed at the corners of the wall. Each of two straps is preferably attached to an opposite side of the upstanding plate such that the straps do not interfere with each other where the straps cross. The straps preferably include threaded ends and the upstanding plates preferably have threaded receptacles sized to accept the threaded ends of the straps such that the straps can be tensioned before and/or after installation. In one embodiment, the upstanding plates are bolted through a bottom surface of the wall into a threaded anchor plate at floor level, and the threaded anchor plate is attached to a top of a wall on a floor below.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to framing systems generally, and more particularly to light gauge framing systems.  
         [0003]     2. Discussion of the Background  
         [0004]     Light gauge framing, especially light gauge steel framing, is becoming an increasingly popular alternative to wood framing in both residential and commercial construction. Structures built with light gauge framing, like other structures, must resist natural forces such as windstorms and earthquakes. “Shear elements” is the name given to elements of the structure that resist these forces. In light gauge framing, the shear elements are typically shear walls.  
         [0005]     Shear walls are typically constructed by either 1) applying a strong panel product such as plywood on the outside of a wall framed with light gauge elements, or 2) applying a tension strap to the outside of such a light gauge framed wall (as used herein, “framed wall” refers to a wall constructed with spaced-apart studs). The requirement for a strong panel material such as plywood in the first method is undesirable because these panel materials cost more than alternative, lower strength panel materials. The second method of applying tension straps to the outside of the framed wall is undesirable for at least two reasons. First, applying tension straps on the exterior (either the inward or outward facing side) of a framed wall interferes with materials (e.g., drywall or plywood) placed over the straps. Second, installing the straps can be problematic. On the one hand, if the straps are installed before the wall is in place, the wall cannot be adjusted to account for on-site conditions. Alternatively, if the straps are installed after the wall is in place, the straps are often simply screwed or tack-welded in place without being under tension. This results in a fairly large displacement before the straps have any effect, thereby decreasing the effectiveness of the straps.  
         [0006]     What is needed is an improved method for constructing a light gauge shear wall that can be easily manufactured and installed in a structure and that does not interfere with subsequently installed construction materials.  
       SUMMARY  
       [0007]     The present invention meets the aforementioned need to a great extent by providing a framed shear wall having a pair of crossed tension straps passing through the studs that make up the shear wall. The straps are preferably rods or cables and are preferably attached to upstanding plates installed at the corners of the wall. In highly preferred embodiments, each of two straps is attached to an opposite side of the upstanding plate such that the straps do not interfere with each other (i.e., one strap does not cause a deflection in the other strap) where the straps cross. The straps preferably include threaded ends and the upstanding plates preferably have threaded receptacles sized to accept the threaded ends of the straps such that the straps can be tensioned before and/or after installation.  
         [0008]     In one embodiment of the invention, the upstanding plates are bolted through a bottom surface of the wall into a threaded anchor plate at floor level. Preferably, the threaded anchor plate is welded to a top of a wall on a floor below. In highly preferred embodiments, the threaded plate is welded to the top of the wall on the floor below before the wall below is installed, and flooring materials (e.g., concrete) are installed around the threaded plate. In this way, a wall above such a floor can be installed by simply bolting the wall to the threaded plate. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     A more complete appreciation of the invention and many of the attendant features and advantages thereof will be readily obtained as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a perspective view of two connected shear wall according to a preferred embodiment of the invention.  
         [0011]      FIG. 2  is a side view of the shear walls of  FIG. 1 .  
         [0012]      FIG. 3  is a perspective view of a corner interconnection between the shear walls of  FIGS. 1 and 2 .  
         [0013]      FIG. 4  is a perspective exploded view of the corner interconnection of  FIG. 3 .  
         [0014]      FIG. 5  is a side view of a T plate of one of the corners of the walls of  FIGS. 1-4 .  
         [0015]      FIG. 6  is a bottom view of the T plate of  FIG. 5 .  
         [0016]      FIG. 7  is a side view of the corner interconnection of  FIG. 3 .  
     
    
     DETAILED DESCRIPTION  
       [0017]     The present invention will be discussed with reference to preferred embodiments of light gauge framed shear walls. Specific details are set forth in order to provide a thorough understanding of the present invention. The preferred embodiments discussed herein should not be understood to limit the invention. Furthermore, for ease of understanding, certain method steps are delineated as separate steps; however, these steps should not be construed as necessarily distinct nor order dependent in their performance.  
         [0018]      FIG. 1  is a perspective view and  FIG. 2  is a side view of two attached shear walls  100  according to a preferred embodiment of the present invention. Each of the shear walls  100  comprises a plurality of vertically oriented, spaced-apart studs  110 . Three studs  110  are ganged together at the sides of each of the walls  100  for added strength. The studs  110  are connected by a bottom channel  130  and a top channel  140 . A hollow rectangular member  150  is installed on the top face of the top channel  150  opposite the side of the channel  150  that accepts the studs  110 .  
         [0019]     Each of the walls  110  also includes two crossed rods  120  attached to upstanding plates  160  on opposite corners of the wall  100 . The crossed rods  120  provide shear strength to the walls  100  and perform the function of the panel or straps in conventional shear walls. The rods  120  pass through holes in each of the studs  110  such that the rods are positioned entirely in the interior of the walls  100  such that no portion of the rods  110  extend past either the front or rear faces of the studs  110  or channels  130 ,  140 . This allows materials such as drywall or paneling to be attached to the walls  100  without interference from the rods  120 .  
         [0020]     A perspective view of an upper corner  101  and a lower corner  102  of the connected walls  100  of  FIGS. 1 and 2  is illustrated in  FIG. 3 , and an exploded perspective view of these corners  101 ,  102  is illustrated in  FIG. 4 . The upper corner  101  is reinforced by a T plate  160  formed by a base plate  162  and an upstanding plate  161 . The base plate  162  of the T plate  160  is positioned in the channel  140 . A face plate  170  is preferably welded to an interior face  110   a  of the innermost stud  110 , with the upper surface  170   a  of the face plate  170  welded to the upper surface  140   a  of the channel  140 . The interior edge  161   a  of the upstanding plate  161  and the interior edge  162   a  of the base plate  162  are preferably welded to the face plate  170 , with the base plate  162  also welded to the top surface  140   a  of the channel  140 . The base plate  162  of the upper corner  101  is shown with a plurality of holes  163 . These holes are not necessary when the T plate  160  is installed in an upper corner  101  (the holes  163  are necessary when the T plate  160  is used in a lower corner as will be discussed below) and thus may be omitted if desired. In preferred embodiments, the T plate  160  and the face plate  170  are welded in the corner  101  prior to installation and preferably at the factory.  
         [0021]     The upstanding plate  161  of the T plate  160  also includes a block  164  with a female threaded hole  165  sized to accept a threaded end  121  of rod  120 . Opposite ends of any rod  120  are threaded in the opposite directions (i.e., one end is right-hand threaded and the opposite end is left-hand threaded) and blocks  164  in corresponding corners are threaded to match the end  121  of the rods  120 . This is done so that when the rod is rotated, the blocks  164  on opposite ends of the rod  120  are either drawn in to increase tension on the rod  120  or pushed outward to release tension on the rod  120  depending on the direction in which the rod  120  is rotated. The blocks  164  are also preferably welded to the upstanding plate  160  in both the upper and lower corners  101 ,  102  prior to installation and more preferably at the factory.  
         [0022]     A rectangular member  150  is preferably welded to the top of the upper channel  140 . The rectangular member  150  provides increased rigidity to the top of upper channel  140 , which is especially desirable where a floor such as a concrete floor will be cast in place on top of the lower wall  110 . The rectangular member  150  is also preferably welded to the upper channel  140  prior to installation and preferably at the factory.  
         [0023]     The upper and lower corners  101 ,  102  are separated by a rectangular spacer  180  with a width W 1  sized to match a width W 2  of the rectangular member  150 . The height H of the spacer  180  is chosen to match a thickness of a floor to be installed between the walls  100 . The floor may be any material, and is most often concrete. The spacer  180  is also preferably attached to rectangular member  150  prior to installation and preferably at the factory.  
         [0024]     An anchor plate  132  is attached to the top of the spacer  180 . A side view of the anchor plate  132  and a bottom view of the anchor plate  132  are shown in  FIGS. 5 and 6 , respectively. The anchor plate  132  includes four holes  134 . Threaded nuts  133  aligned with each of the holes  131  are welded to a bottom surface  132   a  of the anchor plate  132 . The holes  134  and nuts  133  are positioned such that they can be fitted inside the spacer  180 . The anchor plate  132  is preferably welded to the spacer  180  before the wall  100  is installed, and more preferably still at the factory. Thus, in preferred embodiments, the a wall  110  leaves the factory with a rectangular member  150  welded to the top of channel  140  and with a T plate  160  with block  164 , a face plate  170 , a spacer  180  and an anchor plate  132  all welded in the positions described above at each of the upper corners  101  at the factory.  
         [0025]     The lower corner  102  of the wall  110  is also reinforced with a T plate  160  and a face plate  170  installed in the similar manner as the upper corner  101 . That is, the base plate  162  of the T plate  160  is welded to the upper interior surface  130   a  of the lower channel  130  and to the face plate  170 , and the face plate  170  is welded to an inside face  110   a  of an interior corner stud  110  and the interior upper surface  130   a  of the channel  130 . Like the lower corner  101 , the T plate  160  and the face plate  170  are preferably welded prior to installation of the wall  100  and more preferably at the factory. Unlike the T plate  160  in the upper corner  101 , it is necessary for the T plate  160  in the lower corner  102  to have holes  163  formed in base plate  162 . The lower channel  130  also has a plurality of holes  131  in positions corresponding to the holes  163  in the base plate  162 .  
         [0026]     The threaded ends  121  of the rods  120  are also preferably inserted into the blocks  164  of the T plates  160  at the factory in both the upper corner  101  and the lower corner  102 , although they are preferably not under tension. Alternatively, the rods  120  may be installed at the work site. Each of the interior studs  110  has two holes formed therein, one for each of the crossed rods  120  as shown in  FIG. 1 . The blocks  164  of T plates  160  are positioned on opposite sides of the upstanding plates  161  on T plates on opposite sides of the wall  100 . That is, the blocks  164  on the upper left hand and lower right hand corners of a wall  100  are on the same side of their respective upstanding plates  161 , and the upper right hand and lower left hand corners of the same wall  100  have their blocks  164  on the opposites sides of upstanding plate  161  as shown in  FIGS. 3 and 4 . In this fashion, the two rods  120  are in parallel spaced apart planes and do not cause any deflection in each other even though they are both within the interior of the wall  100 .  
         [0027]     With each of the walls  100  configured in the preferred manner described above, installation is greatly simplified. When walls  100  on a lower floor have been installed, the spacers  180  and anchors  132  protrude above the rectangular member  150 . Next, a floor is installed such that the top surface is at the height of the top of the anchor plate  132 . When the floor is concrete, the concrete is simply screeded to the top of the anchor plate  132 . Once the floor is installed, the walls corresponding to that floor are simply placed in the desired location and secured to the anchor plates  132  with a plurality (4 are used in preferred embodiments) of bolts  166 . As shown in  FIG. 7 , the bolts  166  extend through holes  163  in the base plate  162 , the holes  131  in the lower channel  130 , the holes  133  in the anchor plate  132 , and into the threaded nuts  133 . The rods  120  are then adjusted to the desired tension and the walls  100  are then ready for drywall or other desired finishing materials. This allows for very fast construction as compared to other methods. In addition, the rods  120  are at tension and are contained within the interior of the walls  100  so as not to interfere with the installation of drywall, plywood or other materials attached to the exterior surfaces of the walls  100 .  
         [0028]     Those of skill in the art will recognize that it is not necessary for the anchor plates  132  to be attached to walls on the floor below and that the anchor plates  132  can simply be attached to a floor below. Alternatively, the walls  100  may be attached to the floor without the use of anchor plates  132 . For example, when the walls  100  are installed over wood flooring, screws may be used in place of the bolts  166 . As another example, when the walls are installed over concrete floors, anchor upstanding sill bolts may be cast in place in the concrete floor in positions such that they correspond to the holes  163  in the base plate  162  of T plate  160  and the walls  100  may be secured in place using nuts threaded onto the sill bolts.  
         [0029]     It should also be noted that rods having turnbuckles are used rather than threaded rods and threaded mating blocks in some embodiments of the invention. This allows the rods (or cables) to be fixedly attached to the corners of the wall and be tensioned through adjustment of the turnbuckle.  
         [0030]     Obviously, numerous other modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.