Patent Publication Number: US-9896844-B2

Title: I-joists and method of fabrication thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. provisional application Ser. No. 62/193,329, filed on Jul. 16, 2015. All documents above are incorporated herein in their entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to engineered wood. More specifically, the present invention is concerned with I-joists and methods of fabrication thereof. 
     BACKGROUND OF THE INVENTION 
     In the field of engineered wood, open web joists are structural trusses generally comprising parallel chords and a triangulated web. Open web joists as known in the art may have a sawn lumber web (not shown), glued-laminated timber (glulam) web (see  FIG. 1 ), or a metallic web (see  FIG. 2 ), metallic connectors (see  FIG. 3 ), or combination thereof (not shown). 
     I-joists are manufactured structural building components resembling the letter “I”, generally used as floor joists and rafters for example. 
     As shown for example in  FIGS. 4A, 4B and 4C , an I-joist  10  includes flanges  12  on each side of a web  14 . The flanges  12  may be made of laminated veneer lumber or sawn lumber, with a width in range comprised between 1½″ to 3½″. The web or center  14  of the I-joist  10  is commonly made of plywood or oriented strand board (OSB). 
     As illustrated in  FIG. 4C , such I-joists can be manufactured with a range of height of the web  14  between the flanges  12  and with a range of width for the web  14 . They may also have a variety of grade for the flange. The web  14  is joined on each longitudinal edge thereof to a flange  12  by a joint  16  as best seen in  FIG. 4B . The edge  17  of the web  14  is glued in a groove of the flanges  12 . 
     There is still a need in the art for I-joists and methods of fabrication thereof. 
     SUMMARY OF THE INVENTION 
     More specifically, in accordance with the present invention, there is provided an I-joist comprising a web and flanges, the web being connected on each longitudinal edge thereof to a flange, wherein the I-joist further comprises chords, the chords being connected to the web on at least one side of the web. 
     There is further provided a method for fabricating a I-joist, comprising connecting a flange on each longitudinal edge of a web and connecting chords on at least one side of the web. 
     There is further provided a method for fabricating an open web I-joist, comprising providing a web; cutting out portions of the web; connecting a flange on each longitudinal edge of the web; and connecting chords on at least one side of the web. 
     Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the appended drawings: 
         FIG. 1  shows an open web joist with a glulam web as known in the art; 
         FIG. 2  shows an open web joist with a metal web as known in the art; 
         FIG. 3  shows an open web joist with metallic connectors as known in the art; 
         FIG. 4A  is a perspective view of a I-joist as known in the art; 
         FIG. 4B  is a detail of  FIG. 4A ; 
         FIG. 4C  shows side view of different I-joists; 
         FIG. 5A  is a perspective view of an open web I-joist according to an embodiment of an aspect of the present invention; 
         FIG. 5B  is a detail of  FIG. 5A ; and 
         FIG. 6A  shows a perspective view of a I-joist according to an embodiment of an aspect of the present invention; 
         FIG. 6B  is a front view of the I-joist of  FIG. 6A ; and 
         FIG. 7  is a schematical view of an open web I-joist according to an embodiment of an aspect of the present invention; and 
         FIG. 8  is a schematical view of an open web I-joist according to an embodiment of an aspect of the present invention; and 
         FIG. 9  is a schematical view of an open web I-joist according to an embodiment of an aspect of the present invention. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     The present invention is illustrated in further details by the following non-limiting examples. 
     A method according to an embodiment of an aspect of the invention comprises manufacturing an I joist, cutting the web thereof corresponding to a target open web, and securing chords  22   a ,  22   b  for reinforcement. These last two steps may be inverted. 
     In the first step, an I-joist as described in relation to  FIG. 4A  for example is manufactured. The flanges may be in wood for example, such as laminated veneer lumber or sawn lumber, or in a metal such as steel for example. The web may be in oriented strand board (OSB), plywood, sawn lumber or glued-laminated timber (glulam), or in a metal such as steel for example. 
     Then, the web of the I-joist is cut out, using a router for example, following a predetermined pattern. As best seen in  FIG. 5B , portions  20 ,  24  of the web are saved at positions ( 20 ), ( 24 ) for supporting the chords  22   a , 22   b.    
     Chords  22   a ,  22   b  are connected either on one side of the web parts  20  preserved in between the parallel flanges  12 , or on both sides thereof. The chords maybe in wood, for example in sawn lumber or glued-laminated timber (glulam), or in a metal such as steel for example. The flanges  12 , chords  22   a , 22   b  and the web are in a wood material for example, the flanges  12  and the chords  22   a ,  22   b  may connected together by the web portions  24  preserved at the corners as just described hereinabove, best seen in  FIG. 5B , all glued together using structural glue. In case of metal parts, welding can be used. 
     Openings may be provided in the web prior to connecting to web to the flanges. 
     In the embodiments illustrated in  FIGS. 5 to 7 , the chords  22   a ,  22   b  include diagonal chords  22   b  and chords  22   a  perpendicular to the flanges  12 . In the embodiment illustrated in  FIGS. 8 and 9 , only diagonal chords  22   b  are used over a length of the I-joist; moreover, the web is saved at some parts of the I-joist, such as end parts  140   a ,  140   b ,  140   c , while the rest of the web between the chords is open. The web may also be saved at central parts (not shown). 
     The present invention provides fabricating an open web joist having a patterned web as desired. 
     The open web joist may have trimmable ends  40 , for size adjustment. The open web joist may have a web with openings of a predetermined shape allowing vent tubing to run therethrough for example. 
     The present method thus allows providing an open web wood joist comprising openings at various target locations between the flanges, while allowing structural properties comparable to those of I-joist. 
     The present open web joist comprises flanges, in wood for example, and chords, in wood for example, in a unique structural combination. The present open web joist does not require finger joints or metal connectors between the flanges and the chords, as web parts connect the flanges and the chords together. It allows for the passage of electrical wiring, plumbing and duckwork. 
     A method according to an embodiment of another aspect of the invention comprises manufacturing an I-joist and securing chords  22   a ,  22   b  for reinforcement, thereby forming an hybrid I-joist  50  as illustrated for example in  FIG. 7 . 
     The chords  22   a ,  22   b  may be glued to the web  14  using a structural adhesive. 
     The I-joist  50  comprises flanges, in wood such as laminated veneer lumber or sawn lumber for example, or metal such as steel for example, a web in wood such as oriented strand board (OSB), plywood, sawn lumber or glued-laminated timber (glulam) for example, or metal such as steel for example, and chords, in wood such as glued-laminated timber (glulam) or sawn lumber for example, or in a metal such as steel for example, in a unique structural combination. 
     Such hybrid I-joist  50  has structural properties comparable to those of open web joists known in the art. It allows for the passage of electrical wiring, plumbing and duckwork by drilling and cutting the web. 
     The hybrid I-joist may be used as replacement of known I-joist, open web joist, solid sawn lumber, structural composite lumber or glued-laminated timber. 
     The scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.