AU2017330164B2 - Structural member - Google Patents
Structural member Download PDFInfo
- Publication number
- AU2017330164B2 AU2017330164B2 AU2017330164A AU2017330164A AU2017330164B2 AU 2017330164 B2 AU2017330164 B2 AU 2017330164B2 AU 2017330164 A AU2017330164 A AU 2017330164A AU 2017330164 A AU2017330164 A AU 2017330164A AU 2017330164 B2 AU2017330164 B2 AU 2017330164B2
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- Australia
- Prior art keywords
- structural member
- web portion
- structural
- subject
- material used
- Prior art date
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04D—ROOF COVERINGS; SKY-LIGHTS; GUTTERS; ROOF-WORKING TOOLS
- E04D13/00—Special arrangements or devices in connection with roof coverings; Protection against birds; Roof drainage ; Sky-lights
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D47/00—Making rigid structural elements or units, e.g. honeycomb structures
- B21D47/01—Making rigid structural elements or units, e.g. honeycomb structures beams or pillars
-
- 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
- E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
- E04C3/06—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal with substantially solid, i.e. unapertured, web
- E04C3/07—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal with substantially solid, i.e. unapertured, web at least partly of bent or otherwise deformed strip- or sheet-like material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
- B21D5/06—Bending sheet metal along straight lines, e.g. to form simple curves by drawing procedure making use of dies or forming-rollers, e.g. making profiles
- B21D5/08—Bending sheet metal along straight lines, e.g. to form simple curves by drawing procedure making use of dies or forming-rollers, e.g. making profiles making use of forming-rollers
- B21D5/086—Bending sheet metal along straight lines, e.g. to form simple curves by drawing procedure making use of dies or forming-rollers, e.g. making profiles making use of forming-rollers for obtaining closed hollow profiles
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B5/00—Floors; Floor construction with regard to insulation; Connections specially adapted therefor
- E04B5/02—Load-carrying floor structures formed substantially of prefabricated units
- E04B5/10—Load-carrying floor structures formed substantially of prefabricated units with metal beams or girders, e.g. with steel lattice girders
-
- 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
- E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
- E04C2003/0404—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects
- E04C2003/0408—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by assembly or the cross-section
- E04C2003/0421—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by assembly or the cross-section comprising one single unitary part
-
- 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
- E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
- E04C2003/0404—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects
- E04C2003/0426—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by material distribution in cross section
- E04C2003/043—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by material distribution in cross section the hollow cross-section comprising at least one enclosed cavity
-
- 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
- E04C3/04—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal
- E04C2003/0404—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects
- E04C2003/0443—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by substantial shape of the cross-section
- E04C2003/0469—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of metal beams, girders, or joists characterised by cross-sectional aspects characterised by substantial shape of the cross-section triangular-shaped
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Rod-Shaped Construction Members (AREA)
- Roof Covering Using Slabs Or Stiff Sheets (AREA)
- Floor Finish (AREA)
Abstract
The invention relates to a structural member and particularly to a structural member used in the construction industry. In particular, the structural member of the invention is suitable for use in a variety of situations such as a purlin, column, bearer, rafter, joist or girt or other structural member. The structural member is provided with a closed acute trapezoidal cross-sectional shape.
Description
Technical Field
The invention relates to a structural member and particularly to a structural member used in
the construction industry. In particular, the structural member of the invention is suitable for
use in a variety of situations such as a purlin, column, bearer, rafter, joist or girt or other
structural member.
Background Art
At present in the construction industry a wide variety of members are available for use as
structural members, such as purlins, and these include timber battens and steel members
which to date have been typically in Z, C or top hat cross sectional form. Although such units
are suitable for purpose they all suffer from inherent disadvantages.
For example timber battens or members that might be used as purlins have a tendency to
warp overtime and have limited spanning capabilities.
Steel Z, C and top hat section purlins have better spanning capabilities than timber and do not
have a tendency to warp but because of their open structures can become a habitat for
wildlife such as birds and other vermin. This is especially problematic in constructions where
enclosing the walls to keep out birds and other vermin is not viable and yet maintaining
hygiene is essential- such as in dairy sheds.
In the majority of cases, timber battens or members or Z, C and top hat section structural
members require a secondary member to provide stability to the structural member to
thereby achieve a desired design loading.
An object of the invention is to provide a structural member which in use overcomes the
above disadvantages and/or is easily installed and/or saves time and/or reduces costs.
It is an object of the present invention to address one or more of the foregoing problems or
at least to provide the public with a useful choice.
Further objects and advantages of the invention will become apparent from the following
description which is given by way of example only.
Summary of the Invention
In one aspect the invention provides a structural member including:
a) two non-parallel side web portions;
b) a top web portion; and
c) a bottom web portion,
wherein the side, top and bottom web portions are configured to provide the structural
member with a closed acute trapezoidal cross sectional shape in which the top web portion is
substantially parallel to the bottom web portion and wherein the top web portion has a
shorter width than the bottom web portion and the top web portion is formed by at least two
at least partially overlapping layers of material.
In preferred embodiments, the amount of material used to form the top web portion is at
least about 55%, such as at least about 75%, such as at least 85%, such as at least 95%, such
as at least about 100% (such as about 120%) of the amount of material used to form the
bottom web portion. In some embodiments the top web portion will be formed by two
completely overlapping layers of material and the amount of material used to form the top
web portion will be approximately equal to the amount of material used to form the bottom
web portion. Such overlapping layers may be in the form of a simple lap, or the lap may be
crimped in the form of a seam join provided by the two layers.
Preferably the width of the top web portion will be between 25% and 65% of the width of the
bottom web portion.
In preferred embodiments, at least one of the overlapping layers of the top web portion
extends beyond the top web portion and further overlaps with a non-parallel side web portion
in the form of a return. In still further embodiments, each of the overlapping layers extends
beyond the top web portion and further overlaps with the non-parallel side web portions in
the form of two returns. It is believed that the use of at least one additional overlapping
returns provides further rigidity. Where the structural member of the present invention is
formed by roll-forming sheet material, the or each additional overlapping returns may be
created during folding to interlock the edges of the folded sheet material.
Advantageously the closed cross sectional shape of the structural member of the present
invention resists habitation by birds and vermin, primarily because there is no partially
horizontal surface for the birds and vermin to inhabit.
Furthermore, the closed acute trapezoidal cross sectional shape of the structural member of
the present invention typically enables the structural member to be self-stable without the
need for secondary structural members otherwise required for alternate types of structural
members.
Furthermore, and without wishing to be bound by theory, the combination of:
a) the closed acute trapezoidal cross sectional shape of the structural member of the present
invention; and
b) the overlapping layers of material used to form the top web portion,
provides the structural member with particularly useful structural characteristics not
generally provided by other structural members typically used to form purlins, columns,
bearers, rafters, joists or girts. In particular, it is believed that the structural member of the
present invention allows for substantially equal structural performance when the structural
member is subject to loading in both compression and tension. Such loading may be referred
to as in(ward) and out(ward) loading. Such loading can be applied to structural members such
as purlins as a result of snow and wind loading. As used herein, "substantially equal" with
respect to structural performance will typically mean within 20%, such as within 10%, such as
within 5%, for example within 2%.
It would be expected that a typical Z or C form purlin would exhibit substantially equal
structural performance when the purlin is subject to loading in both compression (inward)
and tension (outward) loading by virtue of the top/bottom symmetry of the cross-sectional
profile.
It would be expected that a typical top hat purlin would exhibit substantially unequal
structural performance when the purlin is subject to loading in compression (inward) versus
tension (outward) loading by virtue of the top/bottom asymmetry of the cross-sectional
profile.
Advantageously, the present invention may achieve substantially equal structural
performance when the purlin is subject to loading in both compression (inward) and tension
(outward) loading despite the top/bottom asymmetry because of the clever use of at least
two at least partially overlapping layers of material in the top web portion.
In preferred embodiments the structural member of the present invention may be formed by
folding sheet material, such as sheet metal. The folding of the sheet material may create folds
having varying radii of curvature. These radii may range from a very small radius to essentially
provide a sharp fold having a corner to a large radius to provide a noticeably curved edge.
Preferably the structural member is formed with a curved edge at each of the boundaries of
the top, non-parallel side and bottom web portions.
Conveniently, when the structural member is formed by folding sheet metal, two opposite
edges of the sheet metal may be brought into proximity and overlapped by the process of
folding the sheet metal so as to allow for the formation of the overlapping layers of material
forming the top web portion. This may take the form of a simple lap, or the lap may be
crimped in the form of a seam join provided by the two layers. The overlapping layers may be
fixed together in at least one of the: top web portion; and/or either side web portion where
at least one of the overlapping layers is provided with a return. The fixing together may use
one or more of: screw; bolt; rivet; nail; adhesive; seam lock; braze; solder and/or weld.
Such sheet metal may be cold rolled prior to folding. The sheet metal may be flat steel and is
preferably galvanised and formed flat but can if need be formed from other shapes.
In a further aspect the invention provides a roll formed and folded structural member having
a closed acute trapezoidal cross sectional shape, the structural member being self stable and
having one overlapping wall formed during a folding step of its manufacture, the member
being provided with a substantially equal loading inwards and outwards created by the non
parallel sides formed in the folding step.
As used herein the expressions "loading inwards" and "loading outwards" refer to load testing
which may be performed virtually (using modelling) or in actuality (such as to destruction of a
structural member). The loading may be performed using a single span model and may involve uniformly distributed loads. The loading may be to a predetermined value, or may be increased to the point of failure of the structural member.
There is no particular restriction on the dimensions of the two non-parallel side web portions,
although it is preferred that the width of such non-parallel side web portions be within 25%
of each other, such as within 15%, such as within 5% of eachother. It will be appreciated that
where there is a significant difference between the width of the non-parallel side web
portions, the structural member will adopt an irregular trapezoidal form. In preferred
embodiments, the width of such non-parallel side web portions is approximately the same.
In some embodiments the width of at least one of the side web portions is between 1.3 and
3 times the width of the bottom web portion, such as between 1.5 and 2.5 times. In further
embodiments the width of both of the side web portions is between 1.3 and 3 times the width
of the bottom web portion, such as between 1.5 and 2.5 times. In still further embodiments
the width of both of the side web portions is approximately twice the width of the bottom
web portion.
It will be understood that in the closed acute trapezoidal cross sectional shape of the
structural member of the invention, the plane of the bottom web portion and the plane of the
first adjacent side web portion intersect internally in the structural member at an acute angle
(referred to herein as a°). Furthermore, the plane of the bottom web portion and the plane
of the second adjacent side web portion intersect internally in the structural member at an
acute angle (referred to herein as §°). There is substantial scope for variation of each of angles
c and B° and each of these angles may be the same or different. In some embodiments, a
and D° are each independently selected from between 600 and 890, such as between 70 and
85°. In preferred embodiments, each of c and ° are approximately the same and are
between 80° and 830, such as approximately 81.50 or approximately 820.
Where the cc and P° are the same, it will be understood that the closed acute trapezoidal
cross sectional shape of the structural member of the invention may be described as an
isosceles trapezoidal cross sectional shape.
Swages may be used to add rigidity to the structural member. Each web portion may
optionally include one or more such swages. Generally, however, the top web portion will not incorporate a swage. In preferred embodiments the bottom web portion will incorporate a swage. As the dimensions of the structural member increase, it will generally be preferred to incorporate a swage in one or in each of the side web portions, preferably in each of the side web portions. In larger structural members it may also be preferably to incorporate two swages in in one or in each of the side web portions, preferably in each of the side web portions.
In preferred embodiments, swages are used to impart axial strength to the structural member.
This axial strength may be in the form of compressive, tensional or torsional strength. One or
more of such compressive, tensional or torsional loadings may be provided during certain
events, such as seismic events. For example, during an earthquake, the structural member
may undergo a number of axial loadings, including compressive, tensional and/or torsional
loadings. It is believed that the swages impart a significant increase in the axial strength of
the structural member.
Where the structural member incorporates a plurality of swages, each swage may be of
different dimensions, although generally where the structural member incorporates a
plurality of swages, each swage on the side web portions will be of similar dimensions. Any
swage on the bottom of the structural member may have a similar dimension to any swage
on the side web portion(s), but generally the bottom swage will be smaller in dimension.
In use in a roof situation as a purlin the bottom web portion is typically the side to which a
roof cladding is fixed and the top web portion constitutes the underside of the purlin which
can be fixed to the trusses, for example. This arrangement can be reversed when using the
structural members of the present invention as similar loads can be achieved either way.
In use as a girt in a wall situation the bottom web portion typically is the side to which outer
cladding is fixed and the top web portion is fixed to the wall framing.
In some embodiments the structural members of the present invention are able to span 10 m
which reduces construction costs by eliminating intermediary supports in roof and wall
frames. The non-parallel sides of the trapezoidal cross-sectional profile are also very difficult
for birds and vermin to grip and therefore establish on. The enclosed designs also provides a more aesthetically appealing option to structures created using C, Z or top hat structural members.
Further aspects of the invention which should be considered in all its novel aspects will
become apparent from the following description which is given by way of example only.
Description of the Drawings
Examples of the invention will now be described with reference to the accompanying drawings
in which:
Figures 1 to 4 are cross sections of a first series of exemplary structural members of
the present invention;
Figure 5 shows three cross-sectional profiles of exemplary structural members of the
present invention.
Figure 6 shows four cross-sectional profiles of exemplary structural members of the
present invention.
Figure 7 shows an expanded partial view of the cross-sectional profile of a top web
portion of an exemplary structural member of the present invention.
Figure 8 shows a cross-sectional profile of an exemplary structural member of the
present invention, and measurements in relation to three preferred embodiments of
the invention.
Figure 9 shows the measurements in relation to six additional preferred embodiments
of the invention using the same variables as shown in the cross-sectional profile of
Figure 8, which is not drawn to scale in relation to the measurements of Figure 9.
Figure 10 shows a cross-sectional profile of an exemplary structural member of the
present invention, and measurements in relation to six additional preferred
embodiments of the invention, which is not drawn to scale in relation to the
measurements of ASP150075, ASP150095 and ASP150115.
Figure 11 shows a cross-sectional profile of an exemplary structural member of the
present invention, and measurements in relation to six additional preferred
embodiments of the invention, which is not drawn to scale in relation to the
measurements of ASP250075, ASP250095 and ASP250115
Figure 12 shows a perspective view of how structural members of the present
invention may be used in combination to build a structure
Figure 13 shows section and material properties for exemplary structural members
that were tested for inward/outward loading and axial loading.
Figure 14 shows data from single span inward and outward load testing of exemplary
structural members of the invention.
Figure 15 shows data from axial loading of exemplary structural members of the
invention.
Figure 16 shows data comparing the effect on axial strength of introducing a single
swage into each side web portion.
Figure 17 shows data comparing the effect of introducing fixing members into the
overlapping layers of material forming the top web portion.
Figure 18 illustrates a mode of seam locking the two at least partially overlapping
layers of the top web portion.
Description of the Examples
The examples of the invention will now be described with reference to exemplary structural
members. It is to be appreciated that the structural member can be used in a wide variety of
other situations, including where a cold rolled formed closed section steel frame member
might be specified and used.
In Figures 1 to 4 of the drawings similar parts will be referenced by the same numerals for
ease of convenience.
The first example shown in Figure 1 is a structural member generally indicated by arrow 1
having a closed isosceles trapezoidal cross sectional shape. The member 1 has a bottom web
portion 2 the width of which is about twice that of the top web portion 3. The amount of
material forming the bottom web portion 2 is generally the same as that used to form the top
web portion 3. The top web portion is created during folding by making abutting and
overlapping sections 4, 5 about half the width of the bottom web portion 1. As shown the
side web portions 6, 7 are of equal width.
The second example of structural member 1 shown in Figure 2 has the same general shape as
the member shown in Figure l and in this case the bottom web portion 2 has a swaged section
8 to provide rigidity to the bottom web portion. The overlapping layer 5 of the top web portion 3 extends beyond the top web portion 3 and further overlaps with a non-parallel side web portion 7 intheform of a return9. Further, the overlapping layer 4 of the top web portion
3 extends beyond the top web portion 3 and further overlaps with a non-parallel side web
portion 6 in the form of a return 10. Returns 9, 10 provide rigidity and are created during
folding to interlock the edges of the folded sheet metal. The return 9 may be rebated into the
side web portion 7 so as to provide the outward surface of the return flush to the side web
portion. Such a rebate may form part of a swage.
The third example of closed section member 1 shown in Figure 3 again has the same isosceles
trapezoid shape in cross section as the first two examples. In this case the corners of the
member 1 have a larger radius of curvature which may facilitate easier manufacture. The
angle a° is about 81.5° and is approximately the same as P° described hereinbefore.
The fourth example shown in Figure 4 is similar to the example shown in Figure 3 and has the
side web portions 6, 7 strengthened by the inclusion of swaged sections 11, 12 provided in
side web portions 6, 7 respectively.
Without wishing to be bound by theory, the structural member 1 because of its unique folded
shape reduces the amount of material used in manufacture to provide the same level of
strength and load capacity in both in and out directions at both the top and bottom web
portions as existing C and Z section purlins.
When used in a roof situation as a purlin the top web portion 3 is fixed to the roof framing or
truss and the bottom web portion side 2 has a roof cladding fixed thereto. It is to be
appreciated that if circumstances warrant it the orientation may be reversed. The provision
of the double and overlapped layer in the top web portion 3 provides strength in both inwards
and outwards directions and substantially eliminates twisting in the closed section when the
two layers are joined together by whatever fixings are used to attach them together or fix
cladding thereto. When used as a girt in a wall situation the bottom web portion 2 is typically
the side to which outer cladding is fixed and the top web portion 3 is fixed to the wall's internal
linings.
Figure 5 shows three cross-sectional profiles (14, 16 and 18) having different dimensions and
each having a swage in the bottom web portion (20, 22 and 24 respectively).
Figure 6 shows two cross-section profiles (26 and 28) having different dimensions and each
having a swage in the bottom web portion (30 and 32 respectively). Additionally the cross
sectional profiles (26 and 28) also have swages in each of the non-parallel side web portions
(34 and 36 respectively).
Figure 6 also shows two cross-section profiles (38 and 40) having different dimensions and
each having a swage in the bottom web portion (42 and 44 respectively). Additionally the
cross sectional profiles (38 and 40) also have a pair of swages in each of the non-parallel side
web portions (46 and 48 respectively).
Figure 7 shows an expanded partial view of the top web portion (50) which is common to each
of the cross-sectional profiles shown in Figures 5 and 6. The top web portion is formed by two
fully overlapping layers of material (52 and 54), each overlapping layer provided with returns
(56 and 58 respectively). Return 56 is provided with a rebate 60 in side web portion 62.
Figure 8 shows the measurements in relation to three preferred embodiments of the
invention differing in the gauge of the material used to make the structural member - as
defined by variable "Q".
Figure 9 shows the measurements in relation to six additional preferred embodiments of the
invention using the same variables as shown in the cross-sectional profile of Figure 8, which is
not drawn to scale in relation to the measurements of Figure 9.
Figure 10 shows the measurements in relation to six additional preferred embodiments of the
invention, which is not drawn to scale in relation to the measurements of ASP150075,
ASP150095 and ASP150115.
Figure 11shows the measurements in relation to six additional preferred embodiments of the
invention, which is not drawn to scale in relation to the measurements of ASP250075,
ASP250095 and ASP250115.
As shown in Figures 8 to 11, the top web portion may be between 25% and 65% of the width
of the bottom web portion.
As shown in Figure 8, the amount of material used to form the top web portion may be as
much as 120% of the amount of material used to form the bottom web portion. As shown in
Figure 11, the amount of material used to form the top web portion may be as little as 55% of
the amount of material used to form the bottom web portion.
Figure 12 shows how structural members of the present invention may be used in
combination to build a structure. For example, the bottom web portion of structural member
64 can be butted to the bottom web portion of structural member 66. The butted structural
members may be coupled together (such as welded together), or they may not. In this
embodiment, each of the structural members 64 and 66 include a swage in the respective
bottom web portions so that a cavity 68 is created when the structural members are abutted.
This cavity may be used as conduit (or may contain separate conduit) forwiring, liquids, cable,
etc. The cavity may also be used to house a joining fillet - being a separate unit that couples
structural member 64 to structural member 66. A purlin hanger 70 can be coupled (through
bolts, rivets, screws, nails, welds, etc) to structural member 64 and a further structural
member 72. The terminus 74 of structural member 72 may be cut square, however in this
embodiment it is provided with an angle cut so that the bottom web portion of structural
member 72 is flush to, and coplanar with, the top web portion of structural member 64.
Figure 13 shows section and material properties for structural members that were tested for
inward/outward loading (figure 14) and axial loading (figure 15). The "top flange" equates to
the "bottom web portion" and the "bottom flange" equates to the "top web portion" as used
herein.
Figure 14 shows data from single span inward and outward load testing of exemplary
structural members of the invention. The inward and outward load testing results are
substantially equal. As used herein, "substantially equal" with respect to structural
performance will typically mean within 20%, such as within 10%, such as within 5%, for
example within 2%.
Figure 15 shows data from axial loading of exemplary structural members of the invention. In
these examples, the profile dimensions of A1075, A1010, A1575, A1512, A2010, A2012 and
A2015 are provided in Figure 13. These cross sectional profiles have a single swage on the
bottom web portion and no swaging on the side web portions.
Figure 16 shows data comparing the effect on axial strength of introducing a single swage into
each side web portion, including the overriding deformation characteristics for a given
length/load. For structural members of lengths less than about 4 m there is a significant
increase in axial strength provided by utilising swaging in the side web portions.
Figure 17 shows data comparing the effect of introducing fixing members into the overlapping
layers (52 and 54 in Figure 7) of material forming the top web portion (50 in Figure 7). For
structural members of lengths less than about 3 m the most significant increase in axial
strength is provided by utilising dual Tek screws (by way of example of fixing member) located
in the returns (56 and 58 in Figure 7) down each side of the side web portions. For structural
members greater than 3 m in length the most significant increase in axial strength is provided
by welding the return (56 in Figure 7) into the rebate (60 in Figure 7) on the side web portion
(62 in Figure 7). Otherwise, there is still a noticeable increase in axial strength by fixing the
overlapping layers (52 and 54 in Figure 7) using a Tek screw to the flange (top web portion) of
the flap (return 56 shown in Figure 7).
Figure 18 illustrates a schematic example of a top web portion 76 wherein the two at least
partially overlapping layers (78 and 80) are seam locked (otherwise referred to as seam joint
and grooved seam joint) rather than a simple lap. It is believed that the seam locking will help
reduce distortion during axial loading without any reduction in bending capacity. Seam
locking in this way provides an alternative to the modes of fixing the overlapping layers shown
in Figure 17. The seam lock may be crimped loosely or tightly. In this embodiment, the
amount of material used to form the top web portion, including the material used to form the
seam lock, may exceed the amount of material used to form the bottom web portion.
Where in the foregoing description particular mechanical integers are described it is envisaged
that their mechanical equivalents can be substituted as if they were described herein.
Thus by this invention there is provided a structural member and, particularly, a structural
member used in the building industry which member is suitable for use in a variety of
situations such as a purlin.
Particular examples of the invention have been described and it is envisaged that
improvements and modifications can take place without departing from the scope thereof.
All references, including any patents or patent applications cited in this specification are
hereby incorporated by reference. No admission is made that any reference constitutes prior
art. The discussion of the references states what their authors assert, and the applicants
reserve the right to challenge the accuracy and pertinency of the cited documents. It will be
clearly understood that, although a number of prior art publications are referred to herein,
this reference does not constitute an admission that any of these documents form part of the
common general knowledge in the art, in New Zealand or in any other country.
Throughout this specification, the word "comprise", or variations thereof such as "comprises"
or "comprising", will be understood to imply the inclusion of a stated element, integer or step,
or group of elements integers or steps, but not the exclusion of any other element, integer or
step, or group of elements, integers or steps.
Claims (20)
1. A structural member for use in the construction industry, the structural member
including:
a) two non-parallel side web portions;
b) a top web portion; and
c) a bottom web portion, wherein the side, top and bottom web portions are configured to provide the structural member with a closed acute trapezoidal cross sectional shape in which the top web portion is
substantially parallel to the bottom web portion and wherein the top web portion has a
shorter width than the bottom web portion and the top web portion is formed by at least two
at least partially overlapping layers of material,
wherein the closed acute trapezoidal cross sectional shape extends for the majority of the
length of the structural member.
2. The structural member of claim 1 wherein the amount of material used to form the
top web portion is at least about 55% of the amount of material used to form the bottom web
portion.
3. The structural member of claim 1 wherein the amount of material used to form the
top web portion is at least about 85% of the amount of material used to form the bottom web
portion.
4. The structural member of claim 1 wherein the amount of material used to form the
top web portion is at least about 95% of the amount of material used to form the bottom web
portion.
5. The structural member of claim 1 wherein the amount of material used to form the
top web portion is at least about 100% of the amount of material used to form the bottom
web portion.
6. The structural member of any one of claims 1 to 5 wherein the width of the top web
portion is between 25% and 65% of the width of the bottom web portion.
7. The structural member of any one of claims Ito 6 having substantially equal structural
performance when the structural member is subject to loading inwards and outwards.
8. The structural member of any one of claims 1 to 7 having structural performance
when the structural member is subject to inwards force within 20% of the structural
performance when the structural member is subject to outwards force.
9. The structural member of any one of claims 1 to 8 having structural performance
when the structural member is subject to inwards force within 10% of the structural
performance when the structural member is subject to outwards force.
10. The structural member of any one of claims 1 to 9 having structural performance
when the structural member is subject to inwards force within 5% of the structural
performance when the structural member is subject to outwards force.
11. The structural member of any one of claims 1 to 10 having structural performance
when the structural member is subject to inwards force within 2% of the structural
performance when the structural member is subject to outwards force.
12. The structural member of any one of claims 1 to 11, wherein at least one of the
overlapping layers of material is provided with a return extending down a non-parallel side
web portion.
13. The structural member of any one of claims 1 to 12, wherein each of the overlapping
layers of material is provided with a return, each return respectively extending down a non
parallel side web portion.
14. The structural member of any one of claims 1 to 13 made predominantly of steel.
15. The structural member of claim 14 wherein the steel is galvanised.
16. The structural member of any one of claims 1 to 15 wherein the partially overlapping
layers of material of the top web portion are fixed together in at least one of the: top web portion; and/or either side web portion.
17. The structural member of claim 16 wherein the at least two at least partially
overlapping layers of material of the top web portion are fixed together using one or more of:
screw; bolt; rivet; nail; adhesive; seam lock; braze; solder and/or weld.
18. A method of forming the structural member of any one of claims 1 to 17, the method
including the step of folding sheet metal.
19. The method of claim 18, wherein the sheet metal is cold rolled prior to folding.
20. A roll formed and folded structural member for use in the construction industry, the
structural member having a closed acute trapezoidal cross sectional shape, the structural
member being self stable and having one overlapping wall formed during a folding step of its
manufacture, the member being provided with a substantially equal loading inwards and
outwards created by the non-parallel sides formed in the folding step, wherein the closed
acute trapezoidal cross sectional shape extends for the majority of the length of the structural
member.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NZ723145 | 2016-09-20 | ||
| NZ72314516 | 2016-09-20 | ||
| PCT/NZ2017/050121 WO2018056840A1 (en) | 2016-09-20 | 2017-09-20 | Structural member |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2017330164A1 AU2017330164A1 (en) | 2019-05-02 |
| AU2017330164B2 true AU2017330164B2 (en) | 2022-09-29 |
Family
ID=61690596
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2017330164A Active AU2017330164B2 (en) | 2016-09-20 | 2017-09-20 | Structural member |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2017330164B2 (en) |
| WO (1) | WO2018056840A1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2454459A1 (en) * | 1973-11-21 | 1975-05-28 | Salvatore Leone | U-SHAPED METAL CHANNEL AS SUPPORT FOR COMPACT FLOOR CEILINGS MADE OF LIGHTWEIGHT BLOCKS |
| US5307601A (en) * | 1992-02-06 | 1994-05-03 | Mccracken Robert G | Beam member for use in concrete forming apparatus |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19634280A1 (en) * | 1996-08-24 | 1998-02-26 | Forsch Qualitaetszentrum Oderb | Trapezoidal roofing insulating or bridge profile |
| DE10337680A1 (en) * | 2003-08-16 | 2005-03-17 | Hilti Ag | Hollow profile for attaching objects |
-
2017
- 2017-09-20 WO PCT/NZ2017/050121 patent/WO2018056840A1/en not_active Ceased
- 2017-09-20 AU AU2017330164A patent/AU2017330164B2/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2454459A1 (en) * | 1973-11-21 | 1975-05-28 | Salvatore Leone | U-SHAPED METAL CHANNEL AS SUPPORT FOR COMPACT FLOOR CEILINGS MADE OF LIGHTWEIGHT BLOCKS |
| US5307601A (en) * | 1992-02-06 | 1994-05-03 | Mccracken Robert G | Beam member for use in concrete forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2018056840A1 (en) | 2018-03-29 |
| AU2017330164A1 (en) | 2019-05-02 |
| NZ751952A (en) | 2024-03-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PC1 | Assignment before grant (sect. 113) |
Owner name: STEELBONE INNOVATIONS LIMITED Free format text: FORMER APPLICANT(S): PF TRUST SERVICES (2016) LIMITED; WILLIAMS, PHILLIP; WILLIAMS, KATE |
|
| FGA | Letters patent sealed or granted (standard patent) |