AU726289B2

AU726289B2 - A structural member

Info

Publication number: AU726289B2
Application number: AU19539/00A
Authority: AU
Inventors: Kevin Weeks
Original assignee: Weeks Peacock Quality Homes Pty Ltd
Current assignee: Weeks Holdings Pty Ltd
Priority date: 1997-04-30
Filing date: 2000-02-25
Publication date: 2000-11-02
Anticipated expiration: 2018-04-30
Also published as: AU1953900A

Description

Regutation 3.2

AUSTRALIA

Patents Act 1990 CC3MPMx3 I. ''ES E CIF I CA'I' I 0 S Tr2Vin A~nn 1PzLT EN 1I APPLICANT: WEEKS PEACOCK QUALITY HOMES PTY LTD

NUMBER:

FILING DATE: Invention Title: A STRUCTURAL MEMBER The following statement is a full description of this invention, including the best method of performing it known to me: A STRUCTURAL

MEMBER

FIELD OF THE INVENTION The invention relates to a structural member for construction of buildings such as houses. The invention has particular but not exclusive application in use as a chord for forming a roof truss for a building.

PRIOR ART A metal roof truss is commonly constructed with 10 box-section chords and C-section web members. The boxsection chords are formed by two C-sections individually roll formed and then further fabricated by o "dimple formation for locating and/or fastening by welding, riveting, hole punched and bolted or screwed 15 to close the two C-sections. The fabrication of the section is a specialised operation and adds additional cost and time to the manufacture of a chord.

Open sections are generally quicker and cheaper to-

O..

manufacture than box-sections comprising two Csections, but they lack the strength and stiffness required for chords. Thus, whenever open sections, 'such as channel and Z-sections are used in the fabrication of building frames and roof trusses, additional precautions such as providing oversized sections or additional structural support must be taken to compensate for their inherent strength deficiencies.

2 This of course increases the cost of many structures formed therefrom.

In addition, effecting the joints between top and bottom chords and between web members and chords mostly requires specialised joining members or shaping for welding which adds to the cost and complexity of such structures.

SUMMARY OF THE INVENTION According to one aspect the invention resides in a chord having a crosssection including a minor flange, a major flange, and a web interconnecting said flanges and having a section axis at right angles to the longitudinal axis of the chord and wherein:said web includes a linear portion which extends substantially coincident with the section axis, and a divergent portion which extends to one side of said section axis; said minor flange laterally extends from said section axis to said one side; said major flange extends from said divergent portion to the opposite side of said section axis and includes a major flange return which is spaced from the opposite side of the section axis by an amount corresponding to or oo.o slightly greater than the distance that the minor flange extends from the one side of the section axis, and the section configuration being such that a like-sectioned chord can be inverted, inclined and nested with said chord with the respective linear portions abutting each other and with each minor flange in an abutting relationship with the adjacent major flange whereat it is partially confined by the major flange return such that separation of the abutting linear portions is prevented.

According to a second aspect the invention resides in a chord having a cross-section including a minor flange, a major flange, and a web interconnecting said flanges and having a section axis at right angles to the longitudinal axis of the chord and wherein:said web includes a linear portion which extends substantially coincident with the section axis, and a divergent portion which extends to one side of said section axis; said minor flange laterally extends from said section axis to said one S.side; said major flange extends from said divergent portion to the opposite side of said section axis and includes a major flange return which is spaced S: from the opposite side of the section axis by an amount corresponding to or slightly greater than the distance that the minor flange extends from the one side of the section axis, and a the section configuration being such that a like-sectioned chord can be inverted, inclined and nested with said chord with the respective linear portions abutting each other and with the major flange and major flange return of each chord closely enveloping the minor flange of the other chord such that separation of the abutting linear portions is prevented.

NEXT PAGE IS PAGE 7 BRIEF DESCRIPTION OF THE DRAWINGS Several typical embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: FIG. 1 is an end elevation of an elongate open structural member; FIG. 2,3, 4 are perspective views of the member; FIG. 5 is an end elevation of two members nested o* in reverse and inverted orientation with respect to each other; FIG. 6a is a front elevation of an assembled truss with open structural members as top and bottom chord members; FIG. 6b-g shows various connections on the truss shown in Fig. 6a; FIG. 7a-c are views of the interconnection of two open structural members; FIG. 8a-c are views of different attachments of a C-section truss members to a chord; FIG. 9a-c show alternative connections between chords and truss members; and .FIG. 10 shows an alternative structural member.

15 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to Figs. 1, 2, 3 and 4 there is shown an elongate open structural member 10 having a minor flange 12 and a major flange 13 separated by aweb 14. A longitudinal axis llb of the member 10 is 20 shown in Fig 2. The web 14 includes a planar portion 17 and a divergent portion 18. A section axis lla is S..coincident with the linear portion 17.

The minor flange 12 extends from the planar portion 17 at 90 degrees. The minor flange 12 includes a return flange 15. The return flange 15 is parallel to the section axis lla.

"The divergent portion 18 diverges from the section 9 axis lla at an acute included angle indicated by alpha.

The divergent portion 18 is connected to the major flange 13. The major flange 13 includes a broad planar flange portion 19 which is connected to the divergent portion 18 forming an acute included angle. The major flange 13 also includes a return flange 20 parallel to the section axis.

As shown in Fig. 5, two elongate open structural members 30, 31 as described above are able to be nested with one member being in reverse and inverted orientation with respect to the other. To effect nesting minor flanges 32a and 32b are located within major flanges 33b and 33a respectively in abutting relationship. In this position the respective web portions 34a, 34b partly overlie each other thereby allowing fasteners to join both members 30, 31 to 'i prevent lateral movement. The abutting relationship of the respective flanges 32a, 32b, 33a, 33b prevents movement along the section axis. The nesting of the two elongate members forms two closed sections 35, 36 which provide strength and stiffening to the composite member.

Roof trusses 40 as shown in Fig 6 a-g are constructed with elongate open structural members forming top and bottom chords 41,42 and C-section truss members. The connection of the top chord 41 to the bottom chord 42 is shown in fig. 6b. The major flanges 44,45 of the top and bottom chords 41 and 42 respectively are outermost. The minor flange 46 of the top chord 41 is partially located and confined in major flange 45. The rearward flat side 47 of top chord 41 partly overlaps frontward flat side 48 of the bottom chord 42. There is shown an intermediate connection plate 49 between sides 47 and 48. The connection plate 49 is attached to the bottom chord 42 by bolts 50, 51 and to the top chord 41 by bolts 50, 52. An alternative connection is shown in Fig. 9c where top chord 60 is bolted to bottom chord 61 at 62.

Connections of the truss members 43 to the chord members 41,42 is shown in Fig. 6c, 6d, 6f. In Fig. 6d the truss members 43 are crimped and joined to the top chord 41 by bolt 70. In Fig. 6e the truss members 43 *o 15 are attached to the bottom chord 42 by bolt 72. The underlying truss members are at least crimped to accommodate the connection. The connection shown in Fig. 6c has the truss member 43 connected by bolt 71 to the bottom chord 42. The chords 41,42 are proud of the truss members 43 in the truss The apex 80 of the truss 40 is shown in Fig. 6f, 6g. An apex plate 81 serves to connect top chords 41 by bolts 82. The apex plate 81 has recessed ribs 83 to provide additional stiffening. The apex plate 81 also has a recess 84 for the location of a C-section truss member 43. The C-section truss member 43 is connected to the apex plate 81 by bolt 85. Alternative connections in an apex are shown in Fig. 9a and 9b. In 11 Fig. 9a top chords 63 and C-section truss members 64 are connected by bolt 65. Similarly in Fig. 9b the top chords 66 and C-section truss member 67 are connected by bolt 68.

In Fig. 7a-c there is shown chords 90,91 with major flanges 92,93 outermost and minor flange 94 located partially within the major flange 92.

In Fig. 8a-c there is shown attachment of crimped C-section truss members 95 to elongate open structural member chords 96 by bolts 97. The C-section truss member 95 has end 98 crimped presenting a flat surface 99 for connecting to the chord 96. The flat surface 99 is attached to the side of the web portion 100 opposite the narrow flange 101.

15 The embodiment described above provides a number of advantages including efficient roll forming for chord production; provision of a strengthened and stiffer open section member chord with proper orientation of the major flange outermost; the ability to treat or coat the entire chord or composite beam or truss having open sections prior to use; compact truss stacking with chords being proud of truss web members .thereby minimising damage to the truss members during transportation and reducing transport and storage costs; the ability of the chords to overlap for interconnection while maintaining the overlapped chords in line one above the other for symmetry of the truss and todbe easily fastened together at terminations.

l 12 It will of course be realised that while the foregoing has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

*o f

Claims

1. An elongated structural member having a cross-section including a minor flange, a major flange, and a web interconnecting said flanges and having a section axis at right angles to the longitudinal axis of the structural member and wherein:- said web includes a linear portion which extends substantially coincident with the section axis, and a divergent portion which extends to one side of said section axis; said minor flange laterally extends from said section axis to said one side; said major flange extends from said divergent portion to the opposite side of said section axis and includes a major flange return which is spaced from the opposite side of the section axis by an amount corresponding to or slightly greater than the distance o that the minor flange extends from the one side of the section axis, and :the section configuration being such that a like-sectioned structural member can ogo be inverted, inclined and nested with said structural member with the respective linear portions abutting each other and with each minor flange in an abutting relationship with the adjacent major flange whereat it is partially confined by the major flange return such that separation of the abutting linear portions is prevented.

2. An elongate structural member as claimed in claim 1 wherein said linear portion S. extends from the minor flange along a major portion of thesection axis between the flanges and said divergent portion extends at an acute angle from the section axis. 14

3. A chord as claimed in claim 1 or 2, wherein the minor flange includes a minor flange return, the minor flange return abutting the major flange return of an inverted, inclined and nested like-sectioned chord.

4. A truss including upper and lower chords as claimed in any one of claims 1, 2 or 3, wherein the longitudinal axes of the upper and lower chords are inclined at an acute angle with respect to each other.

A chord having a cross-section including a minor flange, a major flange, and a web interconnecting said flanges and having a section axis at right angles to the longitudinal axis of the chord and wherein:- said web includes a linear portion which extends substantially coincident with the section axis, and a divergent portion which extends to one side of said section axis; S•said minor flange laterally extends from said section axis to said one side; said major flange extends from said divergent portion to the opposite side of said section axis and includes a major flange return which is spaced from the opposite side of the section axis by an amount corresponding to or slightly greater than the distance .o that the minor flange extends from the one side of the section axis, and the section configuration being such that a like-sectioned chord can be inverted, inclined and nested with said chord with the respective linear portions abutting each other and with the major flange and major flange return of each chord closely enveloping the minor flange of the other chord such that separation of the abutting linear portions is prevented.

6. A chord as claimed in claim 5, wherein said linear portion extends from the minor flange along a major portion of the section axis between the flanges and said divergent portion extends at an acute angle from the section axis.

7. A chord as claimed in claim 5 or 6, wherein the minor flange includes a minor flange return, the minor flange return abutting the major flange return of an inverted, inclined and nested like-sectioned chord.

8. A truss including upper and lower chords as claimed in any one of claims 5, 6 or 7 wherein the longitudinal axes of the upper and lower chords are inclined at an acute angle with respect to each other. S* S"

9. A chord for a truss substantially as herein described. *A

10. A truss including chords substantially as herein described. So.