Patent Publication Number: US-6212849-B1

Title: Pultruded fiberglass reinforced shear panel

Description:
FIELD OF THE INVENTION 
     This invention relates generally to wall structures and more particularly, to fiberglass reinforced shear panels for providing added shear strength to wall structures. 
     BACKGROUND OF THE INVENTION 
     Wall panels, such as framing wall members or stud walls, generally are used in a wide variety of construction to facilitate erecting walls for a building structure. The wall panels are typically fabricated from wood and include a wall base plate, a wall top plate, and wall studs extending between the top and base plates. To provide the required shear strength of the wall, and to handle lateral loads on the wall, a plywood panel may be nailed to the studs and the top and base plates. The plywood panel is usually nailed to the outer surfaces of the studs at the corners of the structure. In this position, the plywood panel can interfere with the installation of the normal outer sheathing and the final decorative surface of the structure. 
     Problems may arise if the thicknesses of the sheathing and the plywood panel are not the same. The thickness differential may interfere with subsequent installation of for example the exterior siding of the building. Applying the plywood panel to the surfaces of the studs facing the interior of the structure interferes with the installation of drywall, which is typically used to finish interiors of structures. 
     It would be desirable to provide a shear panel that will provide the desired shear strength and not interfere with subsequent installation of the exterior sheathing or interior drywall. 
     SUMMARY OF THE INVENTION 
     These and other objects may be attained by a shear panel configured to be attached within a stud wall between adjoining studs and the top and bottom plates. The shear panel is positioned within the plane of the stud wall and does not extend beyond the plane defined by the outer edges of the studs. Therefore, the shear panel does not interfere with any subsequent installation of exterior sheathing or interior drywall. 
     The shear panel includes, in one embodiment, an elongate I-shaped member, a top shear cap, and a bottom shear cap. The elongate I-shaped member includes a central region and two opposing flanges extending longitudinally along opposing outer edges of the central region. The elongate I-shaped member is configured to fit between adjacent studs with the flanges in face to face, or surface to surface, contact with the faces of adjacent studs. 
     Each shear cap includes an elongate flat section, a first elongate leg section, and a second elongate leg section. The first and second leg sections extend perpendicularly from the elongate flat section, and the leg sections are configured so that an end of the central region of the I-shaped member fits between the legs. The first leg section is positioned inward from a first longitudinal edge of the flat section, and the second leg section is positioned inward from a second longitudinal edge of the flat section of the top shear cap. A first ear section of the cap is formed between the first longitudinal edge and the first leg, and a second ear section of the cap is formed between the second longitudinal edge and the second leg. 
     To install the shear panel in a stud wall of a structure, the top and bottom shear caps are attached to the I-shaped member at opposing ends of the central region. An adhesive material may be used to bond the top shear cap and the bottom shear cap to the I-shaped member of the shear panel during installation into the stud wall. Metal fasteners, for example screws, may also be used. The shear panel is then positioned between adjacent studs in the stud wall with the flanges in surface to surface contact with the side surfaces of the adjacent studs. Next, the top shear cap is fastened to the bottom surface of the top plate, and the bottom shear cap is fastened to the top surface of the bottom plate. 
     The above described shear panel provides added shear strength to a stud wall. Further, the shear panel does not interfere with subsequent installation on the stud wall of exterior sheathing or interior dry wall. Particularly, the shear panel is configured so that the shear panel is positioned within the plane of the stud wall, i.e., the cavity formed by the adjacent studs and the top and bottom plates of the stud wall. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a shear panel, in accordance with an exemplary embodiment of the present invention, mounted in a stud wall. 
     FIG. 2 is a top view of the elongate I-shaped member of the shear panel shown in FIG.  1 . 
     FIG. 3 is a perspective view of the top shear cap of the shear panel shown in FIG.  1 . 
     FIG. 4 is an end view of the top shear cap of the shear panel shown in FIG.  1 . 
     FIG. 5 is a perspective view of the bottom shear cap of the shear panel shown in FIG.  1 . 
     FIG. 6 is an end view of the bottom shear cap of the shear panel shown in FIG.  1 . 
     FIG. 7 is a front view of a shear panel, in accordance with another exemplary embodiment of the present invention, mounted in a stud wall. 
    
    
     DETAILED DESCRIPTION 
     The present invention is generally directed toward a shear panel particularly useful in building construction to provide building walls with added shear strength. Although a specific exemplary geometric configuration of the panel is provided below, it should be understood that other geometric configurations are possible. 
     FIG. 1 is a side view of a shear panel  20  constructed in accordance with one embodiment of the present invention and mounted in a stud wall  22 . Stud wall  22  includes a bottom plate  24  having a top surface  26 , a top plate  28  having a bottom surface  30 , and studs  32 A,  32 B,  32 C, and  32 D extending perpendicularly between bottom plate  24  and top plate  28 . In this configuration, top plate  28  is referred to as a double top plate and is formed by boards  34 A and  34 B. 
     Shear panel  20  includes an elongate I-shaped member  36 , a top shear cap  38 , and a bottom shear cap  40 . Top shear cap  38  is secured to top plate  28  and bottom shear cap  40  is secured to bottom plate  24 . 
     Elongate I-shaped member  36  includes a central region  42 , having a first end  44  and a second end  46 , and two opposing flanges  48  and  50  extending longitudinally along opposing outer edges  52  and  54  respectively of central region  42 . Elongate I-shaped member  36  is configured to fit between adjacent studs  32 B and  32 C with flange  48  in surface to surface contact with a side surface  56  of stud  32 B, and flange  50  in surface to surface contact with a side surface  58  of stud  32 C. Fasteners  60 A,  60 B, and  60 C secure shear panel  20  to top plate  28 . Similarly, shear panel  20  may be secured to bottom plate  24  with fasteners, such as for example fasteners protruding up from bottom plate  24 , or may be secured by nailing or screwing through bottom shear cap  40  into bottom plate  24 . Shear panel  20  may alternatively be secured to top plate  28  by nailing or screwing through top shear cap  38  into top plate  28 . 
     To maximize load carrying capacity, shear panel  20  is typically secured to a concrete foundation  61 . Usually, bolts are embedded in foundation  61  and are configured to protrude up through bottom plate  24 . Alternately, metal tie-downs secured to foundation  61  may be used to secure shear panel  20  to foundation  61 . Additionally, on each succeeding floor of the structure being built, shear panel  20  is secured to shear panel  20  installed on the immediately preceding or lower floor. This arrangement permits the load path to extend to foundation  61 . 
     FIG. 2 is a top view of elongate I-shaped member  36  of shear panel  20  showing central region  42  having outer edges  52  and  54 , and opposing flanges  48  and  50  extending from edges  52  and  54  as described above. 
     Referring to FIGS. 3 and 4, top shear cap  38  includes an elongate flat section  62 , a first elongate leg section  64 , and a second elongate leg section  66 . First and second leg sections  64  and  66  extend perpendicularly from elongate flat section  62 . Leg sections  64  and  66  are configured so that a first end  44  of central region  42  of I-shaped member  36  (see FIGS. 1 and 2) fits between legs  64  and  66 . First leg section  64  is positioned inward from a first longitudinal edge  68  of flat section  62 , and second leg section  66  is positioned inward from a second longitudinal edge  70  of flat section  62  of top shear cap  38 . A first ear section  72  is formed between first longitudinal edge  68  and first leg  64 , and a second ear  74  section is formed between second longitudinal edge  70  and second leg  66 . 
     Referring to FIGS. 5 and 6, bottom shear cap  40  is similar to top shear cap  38  and includes an elongate flat section  76 , a first elongate leg section  78 , and a second elongate leg section  80 . First and second leg sections  78  and  80  extend perpendicularly from elongate flat section  76 . Leg sections  78  and  80  are configured so that a second end  46  of central region  42  of the I-shaped member  36  (see FIGS. 1 and 2) fits between legs  78  and  80 . First leg section  78  is positioned inward from a first longitudinal edge  82  of flat section  76 , and second leg section  80  is positioned inward from a second longitudinal edge  84  of flat section  76  of bottom shear cap  40 . A first ear section  86  is formed between first longitudinal edge  82  and first leg  78 , and a second ear section  88  is formed between second longitudinal edge  84  and second leg  80 . 
     Shear panel  20 , including I-shaped member  36  and top and bottom shear caps  38  and  40 , is fabricated from a fiber reinforced resin composite. Typically, the reinforcing fibers are fiberglass, but other commercially available reinforcing fibers may also be used. Thermosetting resins are generally used in the composite. However, in some applications, thermoplastic resins may also be acceptable for use in the composite. Suitable, non-limiting examples of thermosetting and thermoplastic resins include acrylic resins, polyester resins, polyurethane resins, and the like. In one exemplary embodiment, shear panel  20  is fabricated from a fiber reinforced resin composite using a pultrusion process. In a pultrusion process, a plurality of strands of reinforcing fibers, such as fiberglass, are impregnated with a resin and then the resin and fibers are pulled through a profile die. Typically the plurality of strands of reinforcing fibers are configured to reinforce the entire profile of the pultruded part, with greater numbers of fibers in areas of the profile that need more reinforcing strength. The fibers are first pulled through an impregnating vessel filled with molted resin. Then the fibers and resin are pulled through a profile die that is maintained at an elevated temperature to crosslink the thermosetting resin. After exiting the profile die, the pultruded composite is cooled and cut to length. In pultrusion processes using thermoplastic resins, often a cooling die is used to cool the composite below the melting point of the thermoplastic resin while maintaining the desired profile. 
     To install shear panel  20  in stud wall  22 , top and bottom shear caps  38  and  40  are attached to I-shaped member  36 . Particularly, first end  44  of central region  42  is inserted into top shear cap  38  between cap legs  64  and  66 , and second end  46  of central region  42  is inserted into bottom shear cap  40  between cap legs  78  and  80 . An adhesive material may be used to bond top shear cap  38  and bottom shear cap  40  to I-shaped member  36 . The adhesive material may be a high bond type of adhesive tape including high bond adhesive on both sides. Typically the high bond tape is applied to ends  44  and  46  of central region  42  of I-shaped member  36  prior to inserting ends  44  and  46  into top and bottom shear caps  38  and  40  respectively. The adhesive material may also be a bead of high bond adhesive applied either to ends  44  and  46 , or between legs  64  and  66  of top shear cap  38  and legs  78  and  80  of bottom shear cap  40  prior to the installation of I-shaped member  36  into top and bottom shear caps  38  and  40 . Additionally, metal fasteners, for example screws, may be used to secure shear caps  38  and  40  to I-shaped member  36 . 
     Top shear cap  38  is then fastened to bottom surface  30  of top plate  28  between two adjacent studs  32 B and  32 C with fasteners  60 A,  60 B, and  60 C. Particularly, fastener bolts  60 A,  60 B, and  60 C extend through top plate  28  and ear  72  of top shear cap  38 . Likewise fasteners extend through top plate  28  and ear  74 . Alternately, screws or nails may be used to secure top shear cap  38  to top plate  28 , with the screws or nails extending through ears  72  and  74  into top plate  28 . Bottom shear cap  40  is fastened to top surface  26  of bottom plate  24  between adjacent studs  32 B and  32 C, with fasteners, nails or screws extending through ears  86  and  88  and into bottom plate  24 . 
     The above described shear panel  20  and method of installation provides added shear strength to stud wall  22 . Shear panel  20  will not interfere with subsequent installation onto stud wall  22  of exterior sheathing or interior dry wall. Particularly, shear panel  20  is configured so that shear panel  20  is positioned within the plane of stud wall  22 , i.e., the cavity formed by adjacent studs  32 B and  32 C and top and bottom plates  28  and  26  of stud wall  22 . 
     FIG. 7 shows another embodiment of shear panel  20  mounted in stud wall  22 . A wooden nailing strip  90  is attached to central region  40  of I-shaped member  36 . Nailing strip  90  extends longitudinally along member  36  and is parallel to flanges  48  and  50 . Nailing strip  90  is configured to provide a nailing surface for subsequently installed drywall or exterior sheathing onto stud wall  22 . Nailing strip  90  may be installed on one side or both sides of I-shaped member  36 . Nailing strip  90  is configured so that when shear panel  20  is installed in stud wall  22 , an outer surface  92  of nailing strip  90  is even with the outer surfaces of studs  32   a,    32 B,  32 C and  32 D and form a stud wall plane. 
     From the preceding description of various embodiments of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.