WO2000015922A1

WO2000015922A1 - Structural member

Info

Publication number: WO2000015922A1
Application number: PCT/CA1999/000848
Authority: WO
Inventors: Jean-Luc Sandoz; Sylvain Menard; Sylvain Dumais; Marc Massicotte
Original assignee: Open Joist 2000 Inc.
Priority date: 1998-09-16
Filing date: 1999-09-16
Publication date: 2000-03-23
Also published as: AU5722899A

Abstract

A structural member, such as a reinforced laminated wooden joist, provides reinforcement in the locations where optimum tension takes place on the joist by the addition of a linking member (40) itself made of wood incorporated between laminations of wood (15, 20), thereby producing a significant increase in the weight carrying capacity of the joist while providing no obstacle to the working of the joist on site.

Description

STRUCTURAL MEMBER

FIELD OF THE INVENTION

This invention relates to structural members, and, more particularly, to a structural member such as a reinforced wood joist or similar structural members for increased weight carrying capacity.

BACKGROUND OF THE INVENTION

Typically, the basic goal in constructing wooden trusses, truss beams or joists, also known as structural members, is to minimize the weight of such members while simultaneously maximizing their load bearing capacity.

In order to achieve such optimization, it is necessary to satisfy simultaneously certain requirements which are not necessarily compatible with one another.

In order to remain as competitive as possible, wood product developers have adopted innovative designs in combination with alternative materials to enhance the structural limits and cost effectiveness of engineered wood products.

The preferred method for fabrication of such products is to connect wood boards with an adhesive because of its low cost, workability, and low toxicity. In order to further improve the effectiveness of engineered wood products recent developments have looked at using high strength fiber panels as means of reinforcement.

There exists a need for improved tensile strength of glued laminated structural wooden members without affecting such advantages as the flexibility for on-site modification. Generally speaking, the maximum tension, in a normal application, occurs along the lower laminations of the structural member, such as a beam, thus setting the carrying capacity of the conventional structural member.

Therefore, an increase in strength, more particularly at the lower lamination level, would allow for greater loads to be borne by the structural member. In the alternative, a smaller structural member would be able to bear a same load which could also provide for architectural advantages where space is at a premium.

SUMMARY OF THE INVENTION

The present invention provides a reinforced structural member designed to overcome the above shortcomings.

An aspect of the invention is a structural member including a first elongated member, a second elongated member, a third elongated member and a first linking member. The first elongated member is made of a first material and has a longitudinal axis. The second elongated member is made of the first material and has a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member. The third elongated member is made of the first material, is coupled between the first elongated member and the second elongated member and has a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member. The first linking member is made of a second material, has a longitudinal axis that is substantially the same as the third elongated member and is coupled to the first elongated member, the second elongated member and the third elongated member. Another aspect of the invention is a structural member including a first elongated member, a second elongated member, a plurality of third elongated members and a plurality of first linking members. The first elongated member is made of a first material and has a longitudinal axis. The second elongated member is made of the first material and has a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member. The plurality of third elongated members each are made of the first material, each are coupled between the first elongated member and the second elongated member, each have a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member and each are longitudinally spaced along the longitudinal axis of the third elongated members. The plurality of first linking members each are made of a second material, each have a longitudinal axis that is substantially the same as the third elongated members and each are coupled to the first elongated member, the second elongated member and at least one of the third elongated members.

A further aspect of the present invention is the first material has a first grain direction and the second material has a second grain direction. The first grain direction is substantially perpendicular to the second grain direction.

Further objects and advantages of the present invention will be apparent from the following description, wherein preferred embodiments of the invention are clearly shown.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates a terminal portion of an assembled joist generally; Figure 2 is a perspective view of a terminal portion of an assembled joist incorporating the linking member of the present invention;

Figure 3(a) and (b) are perspective views of a pre- assembled portion of a structural member having reinforcing members inserted.

DETAILED DESCRIPTION OF THE INVENTION

We shall explain in the foregoing use of a linking member in association with a wooden joist but it should be noted that the linking member of the invention could also be used in combination with other structural members such as, without being exhaustive, trusses or truss beams, wood beams, wood I-beams, solid wood, parallel strand lumber, or any other structural member where laminated components form part of its total structure and where maximizing the load bearing capacity would be an asset.

Referring to Figure 1, a wooden joist is indicated generally by reference numeral 10. The joist 10 has upper and lower parallel chords 15 and 20 extending longitudinally. The chords 15 and 20 may deviate from the parallel situation when under load.

A plurality of interconnecting struts 25 are provided in 45° zig-zag arrangement, each strut 25 being terminally joined at both the nearest chord 15 or 20 and to its neighboring strut 25. The interstrut joint 11 partially overlaps the strut/chord joint. It should be noted that the angle of struts will vary between 30-90° depending on the total length of the joist and the specific requirements desired. The end parts of the chords 15 and 20 of the joist 10 are joined by relatively thicker blocks of wood 30, these blocks 30 being generally flush with the chord ends. The thickness of the blocks may be chosen to provide sufficient strength to the joist 10 while still permitting for some of its thickness in wood to be removed by the person in charge of installing the joists, if there is a need for shorter joists to fit in a reduced space once on site. Thus, it is preferred that these end blocks 30 have a longitudinal thickness greater than 1 inches and preferably ranging between that value and 1H inches.

Referring to Figure 2, there is illustrated a terminal portion of an assembled joist incorporating the linking members 40, made of either one piece hard or soft wood, laminated wood, glued wood or pressed wood, and located at a point where terminal block 30 and vertical member 44 meet strut 25.

In a preferred embodiment of the invention, the linking member 40 is generally of rectangular shape and when part of a forty foot joist characterized by its length of about 15 inches, width of about 2.5 inches and thickness of about 1.5 inches. As the total length of the joist is either increased or reduced, the dimensional characteristics of the linking member would be accordingly increased or reduced in order to ensure that principally the points where block 30 and strut 25 meet and vertical member 44 and strut 25 meet are adequately covered by the linking member 40. It should be understood that when in the presence of a forty feet joist that three linking members may be positioned at each terminal portion of said joist.

Referring to Figures 3(a) and (b) , there is illustrated a typical pre-glued, laminated wood structural member section 42, such as a chord 15, in a pre-assembled position. The linking members 40 are first positioned on the middle portion 41 of the laminated chord 15 and glued thereby forming part of portion 41. The portion 41 containing linking members 40 is then placed and glued/sandwiched between two other wood parts 42 and 43 thereby completing the laminated chord 15. Ideally, the positioning of linking members 40 is such that when the chord 15 is assembled with the struts 25 to form the joist/structural member 10 the linking members 40 end up at the meeting point between block 30 and strut 25 and vertical member 40 and strut 25, as illustrated in Figure 2 in close proximity for maximum load bearing capacity. This way improved and maximum perpendicular traction is provided acting to counteract the perpendicular tension to the grain of the wood as well as the longitudinal shear parallel to the grain of the wood.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

WHAT IS CLAIMED IS:

1. A structural member comprising: a. a first elongated member being made of a first material and having a longitudinal axis; b. a second elongated member being made of the first material and having a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member; and c. a third elongated member being made of the first material, being coupled between the first elongated member and the second elongated member and having a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member; and d. a first linking member being made of a second material, having a longitudinal axis that is substantially the same as the third elongated member and being coupled to the first elongated member, the second elongated member and the third elongated member.

2. The structural member recited in claim 1 wherein the first material is a first type of wood and the second material is a second type of wood.

3. The structural member recited in claim 2 wherein the second type of wood is hard wood.

. The structural member recited in claim 2 wherein the second type of wood is soft wood.

5. The structural member recited in claim 2 wherein the second type of wood is laminated wood.

6. The structural member recited in claim 2 wherein the second type of wood is glued wood.

7. The structural member recited in claim 2 wherein the second type of wood is pressed wood.

8. The structural member recited in claim 1 wherein the linking member is coupled to the constituent members using glue.

9. The structural member recited in claim 8 wherein the third member is coupled between the first member and the second member using glue.

10. The structural member recited in claim 1 further comprising: a. an interconnecting strut having a first end and second end, the first end and the second end being longitudinally opposite, the first end being coupled to the first linking member.

11. The structural member recited in claim 10 further comprising: a. a fourth elongated member being made of the first material and having a longitudinal axis; b. a fifth elongated member being made of the first material and having a longitudinal axis substantially parallel to the longitudinal axis of the fourth elongated member; and c. a sixth elongated member being made of the first material, being coupled between the fourth elongated member and the fifth elongated member and having a longitudinal axis substantially parallel to the longitudinal axis of the fourth elongated member; and d. a second linking member being made of a second material, and having a longitudinal axis that is substantially the same as the sixth member and being coupled to the forth elongated member, the fifth elongated member, the sixth elongated member and the second end of the interconnecting strut.

12. The structural member recited in claim 1 wherein the first material has a first grain direction and the second material has a second grain direction, the first grain direction being substantially perpendicular to the second grain direction.

13. A structural member comprising: a. a first elongated member being made of a first material and having a longitudinal axis; b. a second elongated member being made of the first material and having a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member; c. a plurality of third elongated members each being made of the first material, each being coupled between the first elongated member and the second elongated member, each having a longitudinal axis substantially parallel to the longitudinal axis of the first elongated member and each being longitudinally spaced along the longitudinal axis of the third elongated members; and d. a plurality of first linking members each being made of a second material, each having a longitudinal axis that is substantially the same as the third elongated members and each being coupled to the first elongated member, the second elongated member and at least one of the third elongated members.

14. The structural member recited in claim 13 wherein the first material is a first type of wood and the second material is a second type of wood.

15. The structural member recited in claim 14 wherein the second type of wood is hard wood.

16. The structural member recited in claim 14 wherein the second type of wood is soft wood.

17. The structural member recited in claim 14 wherein the second type of wood is laminated wood.

18. The structural member recited in claim 14 wherein the second type of wood is glued wood.

19. The structural member recited in claim 14 wherein the second type of wood is pressed wood.

20. The structural member recited in claim 13 wherein the linking member is coupled to the constituent members using glue.

21. The structural member recited in claim 20 wherein the third member is coupled between the first member and the second member using glue.

22. The structural member recited in claim 13 further comprising: a. a plurality of interconnecting struts each having a first end and second end, each first end and each second end being longitudinally opposite, each first end being coupled to one of the first linking members.

23. The structural member recited in claim 22 further comprising: a. a fourth elongated member being made of the first material and having a longitudinal axis; b. a fifth elongated member being made of the first material and having a longitudinal axis substantially parallel to the longitudinal axis of the fourth elongated member; and c. a plurality of sixth elongated members each being made of the first material, each being coupled between the fourth elongated member and the fifth elongated member, each having a longitudinal axis substantially parallel to the longitudinal axis of the fourth elongated member and each being longitudinally spaced along the axis of the axis of the sixth elongated member; and d. a plurality of second linking members each being made of a second material, each having a longitudinal axis that is substantially the same as the longitudinal axis of the sixth elongated members, each being coupled to the fourth elongated member, the fifth elongated member, at least one of the sixth elongated members and the second end of one of the interconnecting struts.

24. The structural member recited in claim 13 wherein the first material has a first grain direction and the second material has a second grain direction, the first grain direction being substantially perpendicular to the second grain direction.