CA2684087A1 - Timber roof truss - Google Patents
Timber roof truss Download PDFInfo
- Publication number
- CA2684087A1 CA2684087A1 CA002684087A CA2684087A CA2684087A1 CA 2684087 A1 CA2684087 A1 CA 2684087A1 CA 002684087 A CA002684087 A CA 002684087A CA 2684087 A CA2684087 A CA 2684087A CA 2684087 A1 CA2684087 A1 CA 2684087A1
- Authority
- CA
- Canada
- Prior art keywords
- chord
- truss
- lower chord
- upper chord
- timber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/12—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members
- E04C3/17—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members with non-parallel upper and lower edges, e.g. roof trusses
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/38—Arched girders or portal frames
- E04C3/42—Arched girders or portal frames of wood, e.g. units for rafter roofs
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Rod-Shaped Construction Members (AREA)
Abstract
A curved timber roof truss (1 ) is disclosed which includes a two-section lower chord 2(a,b), a first upper chord (3), a second upper chord (4) and a series of webs (5) extending between, and connecting together by plates (6), the lower chords 2(a,b) and the upper chord (3), The webs (5) are of dimensions to restrain the lower chord (2) and/or the upper chord (3) to a curved profile,
Description
YlMBER ROOF TRUSS
THiS iNVENTION relates to a timber roof truss. In particular, it is directed to a timber roof truss in which both upper and lower chords may be curved.
Throughout this specification, unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was, at the priority date, publicly available, known to the public, part of the common general knowledge, or known to be relevant to an attempt to solve any problem with which this specification is concerned.
A roof truss, especially one used to support the roof of a residential structure, is typically maniafactured from timber and comprises upper and lower chords connected by webs extending therebetween, Such a truss is a simple triangle using standard timber sections set on edge with the webs creating a combination of smaller triangles to provide the required rigidity; the upper chord(s) extend beyond where they converge with the lower chord(s) to provide any required eave overhang.
There are a number of disadvantages with such a truss which include (a) it is not possible to create readily a curved ceiling or roof outline as a complex combination of triangles is necessary to approximate the shape required; (b) it is difficult to achieve a smooth curve as supporting battens must be individually adjusted on site using various curved templates; (c) the truss has little lateral stiffness or vertical stability during building construction and thus temporary cross bracing has to be provided until all battening is completed;
(d) with truss members set on edge, only limited width is available for fixing of battens which may require special care on assembly, or additional fittings, especially at butt joints, to avoid weakening the structure; (e) this minimal width can also prevent the use of industry standard tie down bolts and thus more compllcated metal straps and/or brackets are required for the truss assembly; (f) for wider eaves, or for constructions in high wind zones, non-standard top chords or other methods of strengthenirig are required. All of the above disadvantages lead to increased construction costs.
In the prior technology, attempts have been made to address at least some of the above disadvantages by (a) use of specially fabricated unique timber beams or (b) by replacing timber trusses with trusses nianufactured from metal, particularly steel and aluminium. However, a rnetal truss requires relatively sophisticated machinery to manufacture and assemble into the r-equired shape, is not particularly environmentaHy friendly and still requires similar segmentation as discussed above with respect to a timber truss to approximate curves. Consequently, these prior technology solutions have generally been limited to expensive custom-designed horiies, It is thus a general object of the present invention to overcome, or at least arneliorate, one or more of the above-mentioned disadvaritages.
According to a first aspect of the present invention, there is provided a roof truss manufactured from timber, said truss inoluding:
a lower chord:
at least one upper chord; and webs extending between and connecting together said lower chord and a respective said upper chord;
characterized in that said lower chord and/or at least one of said upper chord are of a curved configuration.
Preferably, said timber for said IQwer and upper chords is set on the flat, Preferably, each said lower chord and each said upper chord are of a curved configuratien, Preferably, each said lower chord and said upper chord, when of a curved configuration, comprise a multiple of timber laminates, Optionally, additional laminates can be incorporated where said upper and.
said lower chords converge to provide additional strength to said truss, Optionally, said lower chord can be in multiple sections and joined to form a continuous chord.
Said timber laminates may be laminated together using one or rriore fixing rneans selected from the group comprising nails, screws, rlpple pins and adhesive.
Said connecting together of said lower chord and a respective said upper chord may be by a nail plate, As a second aspect of the present invention, there is provided a method of manufacturing a truss as hereinbefore described, said niethod including:
THiS iNVENTION relates to a timber roof truss. In particular, it is directed to a timber roof truss in which both upper and lower chords may be curved.
Throughout this specification, unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was, at the priority date, publicly available, known to the public, part of the common general knowledge, or known to be relevant to an attempt to solve any problem with which this specification is concerned.
A roof truss, especially one used to support the roof of a residential structure, is typically maniafactured from timber and comprises upper and lower chords connected by webs extending therebetween, Such a truss is a simple triangle using standard timber sections set on edge with the webs creating a combination of smaller triangles to provide the required rigidity; the upper chord(s) extend beyond where they converge with the lower chord(s) to provide any required eave overhang.
There are a number of disadvantages with such a truss which include (a) it is not possible to create readily a curved ceiling or roof outline as a complex combination of triangles is necessary to approximate the shape required; (b) it is difficult to achieve a smooth curve as supporting battens must be individually adjusted on site using various curved templates; (c) the truss has little lateral stiffness or vertical stability during building construction and thus temporary cross bracing has to be provided until all battening is completed;
(d) with truss members set on edge, only limited width is available for fixing of battens which may require special care on assembly, or additional fittings, especially at butt joints, to avoid weakening the structure; (e) this minimal width can also prevent the use of industry standard tie down bolts and thus more compllcated metal straps and/or brackets are required for the truss assembly; (f) for wider eaves, or for constructions in high wind zones, non-standard top chords or other methods of strengthenirig are required. All of the above disadvantages lead to increased construction costs.
In the prior technology, attempts have been made to address at least some of the above disadvantages by (a) use of specially fabricated unique timber beams or (b) by replacing timber trusses with trusses nianufactured from metal, particularly steel and aluminium. However, a rnetal truss requires relatively sophisticated machinery to manufacture and assemble into the r-equired shape, is not particularly environmentaHy friendly and still requires similar segmentation as discussed above with respect to a timber truss to approximate curves. Consequently, these prior technology solutions have generally been limited to expensive custom-designed horiies, It is thus a general object of the present invention to overcome, or at least arneliorate, one or more of the above-mentioned disadvaritages.
According to a first aspect of the present invention, there is provided a roof truss manufactured from timber, said truss inoluding:
a lower chord:
at least one upper chord; and webs extending between and connecting together said lower chord and a respective said upper chord;
characterized in that said lower chord and/or at least one of said upper chord are of a curved configuration.
Preferably, said timber for said IQwer and upper chords is set on the flat, Preferably, each said lower chord and each said upper chord are of a curved configuratien, Preferably, each said lower chord and said upper chord, when of a curved configuration, comprise a multiple of timber laminates, Optionally, additional laminates can be incorporated where said upper and.
said lower chords converge to provide additional strength to said truss, Optionally, said lower chord can be in multiple sections and joined to form a continuous chord.
Said timber laminates may be laminated together using one or rriore fixing rneans selected from the group comprising nails, screws, rlpple pins and adhesive.
Said connecting together of said lower chord and a respective said upper chord may be by a nail plate, As a second aspect of the present invention, there is provided a method of manufacturing a truss as hereinbefore described, said niethod including:
providing a said lower chord;
providing at least one said upper chord, and connecting together said lowerchord and a respective said upper=
chord with said webs, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile, A third aspect of the present invention is the provision of a roof structure which includes:
a multiple of said truss as hereinbefore described assen-7bled to provide a framework for a roof; and one or more battens affixed to the upper sLirface of at least one of said upper chord for supporting sheet material thereon, Said roof structure may also include one or more battens -affixed to the undersurface of said lower chord for supporting sheet material thereon, Optionally, the said roof structure may be adapted to eriable fitting of a tie-down bolt or the like.
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings wherein;
FIG. 1 Is a schematic representation of a structure which includes a truss constructed according to the invention:
FIG, 2 is a sectional view of the structure of FIG. 1 along the line A-A;
and FIG. 3 is a sectional view of the structure of FIG. 1 along the line B-B.
The truss (1) comprises a two-section lower chord 2(a,b), a first upper chord (3), a second upper chord (4), a series of connecting web members (5) and connecting plates (6), Each chord (2,3,4) and web member (5) comprises two layers of straight tin7ber laminated together using any conventional securing means knowri in the art such as nails, screws, ripple pins and similar mechanical fixings, or adhesive. The timber is set on the flat.
Each connecting plate (6) is any suitable nail plate or similar known in the art.
The dimensions of each chord (2,3,4) and web member (5) are selected such that, on assembly to form the truss (1), the two sections 2(a,b) can be butt.
jointed to form a continuous lower chord, and each chord (2,3,4) is restrained to a curved profile by suitable length of the appropriate web members (5), the web menibers (5) being held to the respective chords (2,3,4) using the connecting plates (6), Where the lower chord 2(a,b) and respective upper chord '(3,4) meet, the resultant four-ply laminate (7,8) can be secured together with additional mechanical fixings.
Where the radii of the chords (2,3,4) are approximately 10m, (a) the four-ply ;aminate (7,8) junction of the chords (2,3,4) enable external eaves of approximately 1,4m to be created; (b) the trusses can be at 1800miYi or 2400mni spacing, rather than the 900mm or 1200m spacing of conventional triangular timber trusses; and (c) conventional flat roof sheeting can be readily attached to the curved surfaces of the chords (2,3,4) by timber battens (9) without further modification to follow those curved surfaces.
Should additional strength be necessary for the assembled truss (1), such as in cyclone-prone areas, this additional strength can readily be achieved by using additional laminates in the construction of the chords (2,3,4) and/or by drilling vertically through the chords (2,3,4) and using threaded tie-down bolts (10) as is known in the art.
Also, additional laminates, either the full length of the respective chords (2,3,4) or of a shorter length sandwiched between two of the full length laminates of the chords (2,3,4), could be incorporated into the structure to provide increased strength where the upper and lower chords converge. This increased strength enables a wider eave to be formed, and/or provides more flexibility in the actual positioning of the vertical supports for the overall roof structure, *
The present invention thus offers a number of advantages of the prior art, which include:
wider spacing of trusses enabling greater design freedom in the positioning of cbnstructional features such as large bay windows;
standard timber cuts can be used to create a continuous curved structure, both as an outer roof or inner ceiling;
the convergence of the upper and lower chords provides an increased overall strength for the truss which enables (i) wider externaf eeves to be constructed and (ii) provides flexibility iri the positioning of the vertical supports for the roof structur-e for any given span;
total quantity of timber used for a given structure is approximately the same as more conventional triangular timber trusses;
can readily be adapted for use in high stress areas such as cyclone-prone climates; and provides a curved truss which can be assembled easily from readily available standard component.s, It will be appreciated that the above described embodiment Is only an exemplification of the various aspects of the present invention and that modifications and alterations can be made thereto without departing fron7 the inventive concept as broadly defined in the following claims,
providing at least one said upper chord, and connecting together said lowerchord and a respective said upper=
chord with said webs, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile, A third aspect of the present invention is the provision of a roof structure which includes:
a multiple of said truss as hereinbefore described assen-7bled to provide a framework for a roof; and one or more battens affixed to the upper sLirface of at least one of said upper chord for supporting sheet material thereon, Said roof structure may also include one or more battens -affixed to the undersurface of said lower chord for supporting sheet material thereon, Optionally, the said roof structure may be adapted to eriable fitting of a tie-down bolt or the like.
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings wherein;
FIG. 1 Is a schematic representation of a structure which includes a truss constructed according to the invention:
FIG, 2 is a sectional view of the structure of FIG. 1 along the line A-A;
and FIG. 3 is a sectional view of the structure of FIG. 1 along the line B-B.
The truss (1) comprises a two-section lower chord 2(a,b), a first upper chord (3), a second upper chord (4), a series of connecting web members (5) and connecting plates (6), Each chord (2,3,4) and web member (5) comprises two layers of straight tin7ber laminated together using any conventional securing means knowri in the art such as nails, screws, ripple pins and similar mechanical fixings, or adhesive. The timber is set on the flat.
Each connecting plate (6) is any suitable nail plate or similar known in the art.
The dimensions of each chord (2,3,4) and web member (5) are selected such that, on assembly to form the truss (1), the two sections 2(a,b) can be butt.
jointed to form a continuous lower chord, and each chord (2,3,4) is restrained to a curved profile by suitable length of the appropriate web members (5), the web menibers (5) being held to the respective chords (2,3,4) using the connecting plates (6), Where the lower chord 2(a,b) and respective upper chord '(3,4) meet, the resultant four-ply laminate (7,8) can be secured together with additional mechanical fixings.
Where the radii of the chords (2,3,4) are approximately 10m, (a) the four-ply ;aminate (7,8) junction of the chords (2,3,4) enable external eaves of approximately 1,4m to be created; (b) the trusses can be at 1800miYi or 2400mni spacing, rather than the 900mm or 1200m spacing of conventional triangular timber trusses; and (c) conventional flat roof sheeting can be readily attached to the curved surfaces of the chords (2,3,4) by timber battens (9) without further modification to follow those curved surfaces.
Should additional strength be necessary for the assembled truss (1), such as in cyclone-prone areas, this additional strength can readily be achieved by using additional laminates in the construction of the chords (2,3,4) and/or by drilling vertically through the chords (2,3,4) and using threaded tie-down bolts (10) as is known in the art.
Also, additional laminates, either the full length of the respective chords (2,3,4) or of a shorter length sandwiched between two of the full length laminates of the chords (2,3,4), could be incorporated into the structure to provide increased strength where the upper and lower chords converge. This increased strength enables a wider eave to be formed, and/or provides more flexibility in the actual positioning of the vertical supports for the overall roof structure, *
The present invention thus offers a number of advantages of the prior art, which include:
wider spacing of trusses enabling greater design freedom in the positioning of cbnstructional features such as large bay windows;
standard timber cuts can be used to create a continuous curved structure, both as an outer roof or inner ceiling;
the convergence of the upper and lower chords provides an increased overall strength for the truss which enables (i) wider externaf eeves to be constructed and (ii) provides flexibility iri the positioning of the vertical supports for the roof structur-e for any given span;
total quantity of timber used for a given structure is approximately the same as more conventional triangular timber trusses;
can readily be adapted for use in high stress areas such as cyclone-prone climates; and provides a curved truss which can be assembled easily from readily available standard component.s, It will be appreciated that the above described embodiment Is only an exemplification of the various aspects of the present invention and that modifications and alterations can be made thereto without departing fron7 the inventive concept as broadly defined in the following claims,
Claims (15)
1. A roof truss manufactured from timber, said truss including:
a lower chord;
at least one upper chord; and webs extending between and connecting together said lower chord and a respective said upper chord, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile;
wherein each said lower chord and said upper chord, when of a curved configuration, comprises a continuous strip-like timber laminate set on the flat.
a lower chord;
at least one upper chord; and webs extending between and connecting together said lower chord and a respective said upper chord, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile;
wherein each said lower chord and said upper chord, when of a curved configuration, comprises a continuous strip-like timber laminate set on the flat.
2. A truss as defined in Claim 1 which include two of said upper chord.
3. A truss as defined in Claim 2 wherein, each of said two of said upper chord are in an opposing said curved configuration.
4. A truss as defined in any one of Claims 1 to 3 wherein, each said lower chord and each said upper chord are of a curved configuration.
5. A truss as defined in any one of Claims 1 to 4 wherein, each said lower chord and said upper chord, when of a curved configuration, comprise a multiple of timber laminates.
6. A truss as defined in any one of Claims 1 to 5 wherein, additional laminates are incorporated where said upper and said lower chords converge.
7. A truss as defined in any one of Claims 1 to 6 wherein said lower chord is in multiple sections joined to form a continuous said lower chord.
8. A truss as defined in Claim 5 wherein, said timber laminates are laminated together using one or more fixing means selected from the group comprising nails, screws, ripple pins and adhesive.
9. A truss as defined in any one of Claims 1 to 8 wherein, each said connecting together of said lower chord and a respective said upper chord is by a nail plate.
10. A method of manufacturing a truss as defined in any one of Claims 1 to 9, said method including:
providing a said lower chord;
providing at least one said upper chord; and connecting together said lower chord and a respective said upper chord with said webs, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile.
providing a said lower chord;
providing at least one said upper chord; and connecting together said lower chord and a respective said upper chord with said webs, said webs of dimensions to restrain said lower chord and/or said at least one upper chord to a curved profile.
11. A roof structure which includes:
a multiple of said truss as defined in any one of Claims 1 to 9 assembled to provide a framework for a roof; and one or more battens affixed to the upper surface of at least one of said upper chord for supporting sheet material thereon.
a multiple of said truss as defined in any one of Claims 1 to 9 assembled to provide a framework for a roof; and one or more battens affixed to the upper surface of at least one of said upper chord for supporting sheet material thereon.
12. A roof structure as defined in Claim 11 which includes sheet material affixed to said battens.
13. A roof structure as defined in Claim 11 or Claim 12 which includes one or more battens affixed to the undersurface of said lower chord.
14. A roof structure as defined in Claim 13 which includes sheet material affixed to said battens on said undersurface of said lower chord.
15. A roof structure as defined in any one of Claims 11 to 14 wherein, at least one or more of said truss is adapted to enabling fitting of a tie-down bolt or the like.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2007901897A AU2007901897A0 (en) | 2007-04-12 | Timber roof truss | |
| AU2007901897 | 2007-04-12 | ||
| PCT/AU2008/000498 WO2008124864A1 (en) | 2007-04-12 | 2008-04-09 | Timber roof truss |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2684087A1 true CA2684087A1 (en) | 2008-10-23 |
Family
ID=39863154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002684087A Abandoned CA2684087A1 (en) | 2007-04-12 | 2008-04-09 | Timber roof truss |
Country Status (5)
| Country | Link |
|---|---|
| CN (1) | CN101680225A (en) |
| AU (1) | AU2008238593B2 (en) |
| CA (1) | CA2684087A1 (en) |
| NZ (1) | NZ581039A (en) |
| WO (1) | WO2008124864A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102071742B (en) * | 2010-12-06 | 2012-04-25 | 中国民航大学 | Wood structure rectangular plate net rack |
| CN102493599B (en) * | 2011-12-29 | 2014-06-11 | 黑龙江省七建建筑工程有限责任公司 | Bidirectional composite floor |
| CN109898741A (en) * | 2017-12-07 | 2019-06-18 | 扬州工业职业技术学院 | Novel fabricated triangle timber truss structure |
| CN111005325B (en) * | 2020-01-06 | 2021-07-23 | 中铁宝桥集团有限公司 | Linear lofting method for vertical curve of steel truss girder bridge |
| CN114991374B (en) * | 2022-06-14 | 2023-06-13 | 中建八局总承包建设有限公司 | Inverted arch slope roof structure |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2371421A (en) * | 1942-09-11 | 1945-03-13 | John F Blaski | Wooden roof |
| US4173857A (en) * | 1977-11-22 | 1979-11-13 | Yoshiharu Kosaka | Double-layered wooden arch truss |
| US4393637A (en) * | 1980-10-10 | 1983-07-19 | Mosier Leo D | Wood roof truss construction |
| US4659604A (en) * | 1986-02-20 | 1987-04-21 | Boise Cascade Corporation | Adhesive/nail plate truss assembly |
-
2008
- 2008-04-09 CN CN200880016019A patent/CN101680225A/en active Pending
- 2008-04-09 AU AU2008238593A patent/AU2008238593B2/en not_active Ceased
- 2008-04-09 CA CA002684087A patent/CA2684087A1/en not_active Abandoned
- 2008-04-09 NZ NZ581039A patent/NZ581039A/en not_active IP Right Cessation
- 2008-04-09 WO PCT/AU2008/000498 patent/WO2008124864A1/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| NZ581039A (en) | 2011-05-27 |
| CN101680225A (en) | 2010-03-24 |
| AU2008238593B2 (en) | 2013-03-28 |
| AU2008238593A1 (en) | 2008-10-23 |
| WO2008124864A1 (en) | 2008-10-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |