WO2010014019A2

WO2010014019A2 - Improvements in and relating to methods of construction

Info

Publication number: WO2010014019A2
Application number: PCT/NZ2009/000150
Authority: WO
Inventors: Thomas Rex Collins
Original assignee: Golden Homes Holdings Limited
Priority date: 2008-07-28
Filing date: 2009-07-28
Publication date: 2010-02-04
Also published as: NZ570136A; WO2010014019A3

Abstract

This invention relates to a method of construction, the method including the steps of providing a first and second members, the second member being elongate, attaching an anchor to the first and second members and attaching the sidewalls of the anchor to the second member such that the sidewalls of the anchor extend in a direction substantially parallel with a longitudinal axis of the second member. Also claimed is the support assembly used in the method of the invention.

Description

IMPROVEMENTS IN AND RELATING TO METHODS OF CONSTRUCTION

STATEMENT OF CORRESPONDING APPLICATIONS

This application is based on the provisional specification filed in relation to New Zealand Patent Application Number 570136, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to improvements in and relating to methods of construction and more particularly to a method for improving the resilience of a connection between construction members.

BACKGROUND ART

The use of steel-framing in construction offers many advantages over traditional wood framing. For example:

steel has a consistent material quality;

it is recyclable;

it will not warp, split, crack or creep;

it has a higher strength to weight ratio than timber; and

it is not particularly vulnerable to fire, living organisms such as fungi, bacteria, termites or mould.

Steel-framing also offers a number of advantages to builders including: reduced weight and. bulk compared to wooden framing;

lower levels of scrap and waste;

dimensionally stable i.e. it does not expand or contract with moisture or temperature changes; and

does not require chemical treatment.

While steel-framing has been used for many years in commercial, industrial and large-scale construction applications, its inherent advantages and improvements in technology have also led to its adopted use in residential and smaller-scale applications.

A number of problems arise when using steel-framing in residential applications as will be outlined herein. To aid clarity and avoid prolixity, the present invention will be described with respect to residential applications though it should be appreciated the principles of the present invention may be used in any suitable construction application.

Similarly, the present invention has particular application to steel-framed construction although this should not be seen as limiting as the present invention may also find application in other metal-framed construction.

It is important to ensure that the structural supports of any building are sufficiently strong to withstand large or frequent earthquakes, wind events and other destabilization. The degree of strength required will vary with the potential forces acting on the supports in a destabilising event. New Zealand, Japan and many other countries on, or near, boundaries of tectonic plates or fault-lines are vulnerable to frequent and sometimes large earthquakes and therefore buildings in these countries must be able to withstand comparatively larger forces than those in relatively more stable regions.

Current methods of manufacturing steel-framed buildings involve the use of steel beams with a 'U'-section formed by pressing a steel sheet into shape with two sidewalls extending perpendicular to a rear wall, or 'base', and two rims or flanges extending inwards from the sidewalls to improve the rigidity and strength of the beam. These beams are used as vertical 'uprights' for supporting interior and exterior wall panels.

Typically, the uprights are positioned in place and secured to a steel base channel having two sidewalls and a base. A vertical arm of an angle bracket is attached to the lower end of the upright and the corresponding horizontal arm is rested on the base channel. The uprights are secured to the base channel by placing a square washer above the horizontal arm and inserting a bolt through the washer and channel into the sub-floor on which the channel rests. The angle bracket (and thus the upright) is thereby secured in position by the washer. The sidewalls of the upright are also typically secured to the sidewalls of the base channel by passing screws through overlapping parts of both members.

However, this method of securing the upright to the base channel is vulnerable to damage as the forces placed on the steel uprights are often sufficient to lift the upright away from the channel and bend the washer. The upright may then be loose in position and presents a potentially unstable structure.

Moreover, as these lifting forces are localised at the washer and attaching bolt, the upright may be lifted to such an extent as to tear the base channel. Similar problems are present in the prior art connection between the sidewalls of the base channel and those of the upright, i.e. the lifting force may bend the connecting screw between the sidewalls of the base and upright and in some cases may rip the screw from the base channel.

It would thus be advantageous to provide an improved method of construction to enhance the resilience and/or strength of the connection between steel-framing uprights and the base channel.

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.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION

According to a first aspect of the present invention there is provided a method of construction including the steps of:

- providing a first and second members, the second member being elongate; and

- attaching an anchor to the first and second members

wherein the anchor has a base and at least two sidewalls, and including the step of attaching the sidewalls of the anchor to the second member such that the sidewalls of the anchor extend in a direction substantially parallel with a longitudinal axis of the second member.

According to another aspect of the present invention there is provided a support assembly including:

- first and second members, the second member being elongate; and

- an anchor attached to the first and second members

wherein the anchor has a base and at least two sidewalls, the sidewalls of the anchor being attached to the second member and extending in a direction substantially parallel with a longitudinal axis of the second member. The forces placed on the connection between the first and second members (considering this connection in isolation of others) are dependant on the direction of force and distance from the connection. Thus, the greatest forces incident on the connection result from forces applied transverse to a longitudinal axis of the second member, rather than those applied parallel to the longitudinal axis. As described above, a transverse force will manifest at the connection as a lifting force on one side of the second member as the other side acts as a fulcrum, i.e. the opposing sides respectively experience tensile and compressive forces.

The strength of the connection between the first and second members may be enhanced by the present invention by the provision of the anchor having sidewalls that are attached to the second member and also extend in a parallel direction as a longitudinal axis of the second member. The 'lifting' forces are thus applied as compressive or tensile forces in the planes of the sidewalls. In contrast, in the prior art methods described above, the horizontal bracket arm extends in a direction perpendicular to the upright and connects the upright to the base and therefore the lifting force is converted to a bending moment on the washer.

Preferably, the first member is elongate and has a base and two sidewalls extending from the base.

Preferably, the first member is an elongate steel-framing 'base-channel' having a substantially 'U'-shaped cross-section, with a base and two sidewalls extending substantially perpendicular to the base.

Preferably, the first member sidewalls extend substantially parallel with the second member longitudinal axis. Preferably, the second member is attached to the sidewalls of the first member.

Preferably, the second member is an elongate steel-framing support or 'upright' having a substantially 'U'-shaped cross-section, with a base and two sidewalls extending substantially perpendicular to the base.

Preferably, the anchor is attached to the sidewalls of the first member.

Preferably, the anchor is constructed from a substantially resilient material such as plastic. The use of a resilient anchor may ensure the second member is biased toward a stable, equilibrium position. Thus, any forces applied to the second member may cause only a temporary lifting of the anchor, (i.e. while the lifting force is applied) before returning to position. In contrast, the prior art methods use a steel washer to secure the second member (e.g. an upright) to the first member (e.g. a base channel) and this washer will bend out of shape when sufficient force is applied. The washer will not function as required once bent out of shape.

Preferably, the anchor has a base and two sidewalls respectively corresponding to the base and sidewalls of the second member, the anchor sized to fit between the second member sidewalls.

Preferably, the anchor sidewalls are sufficiently flexible to bend with respect to the base.

Preferably, the anchor sidewalls include at least one groove or indentation to accommodate a fastening means or fixture.

In one alternative embodiment the anchor may have a base and four sidewalls extending perpendicular thereto about a perimeter thereof. As used herein, the term "corresponding", used with respect to the base and sidewalls of the first member and anchor, should be understood to refer to the first member and anchor having a similar size and shape so that the anchor can fit within the first member.

Preferably, the anchor is attached to the base of the first member.

Preferably, the anchor is also attached to a structure to which the first member is attached, e.g., where the first member forms a horizontal track for supporting second members in the form of vertical uprights, the anchor may be attached to a floor or concrete pad on which the track is fixed.

Preferably, the anchor, first and/or second members are attached together suchrthat the sidewalls of the second member are positioned between the sidewalls of the anchor and first member.

Preferably, only one end of the second member is attached to the first member.

Preferably, the anchor, first and/or second members are attached together in a fixed relationship with respect to each other.

Preferably, a fastener is used to secure the anchor, first and/or second members together.

Preferably, the fastener includes one or more of a bolt, screw, Tek-screw, plug, rod, axle, staple or any other fastener capable of extending through the anchor, first and/or second member sidewalls to secure them together.

The present invention may thus provide an improved method of construction to enhance the resistance of steel-framing supports to bending and twisting. BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

Figure 1 shows a representation of a prior art method of securing a steel-frame upright to a base-channel;

Figure 2 shows an isometric view of a method of construction and corresponding support assembly according to one preferred embodiment of the present invention, and

Figure 3 shows an enlarged isometric view of an anchor in a further preferred embodiment of the invention for use in the support assembly of figure 2.

BEST MODES FOR CARRYING OUT THE INVENTION

Figure 2 shows a method of construction and a corresponding support assembly 1 according to one preferred embodiment of the present invention. This method and assembly 1 may overcome some of the disadvantages inherent in the prior art method and assembly 100 shown in figure 1.

The prior art method is now described more fully with respect to figure 1.

Typical steel-framing construction methods use the prior art assembly 100 to attach a steel upright 120 to a base channel 110 which is bolted to a support structure such as a concrete pad 101. The base channel 110 and upright 120 are formed from similar 'U'-shaped cross-section steel beams, each having a base 111 , 121 , and two perpendicular sidewalls 112, 122. The upright 120 is sized to fit within the base channel 110 such that the sidewalls 112, 120 abut with each other and can be secured together at one end of the upright using Tek-screws 102 or the like.

A vertical arm 103a of an angle bracket 103 is attached to the base 121 of the upright via a Tek screw 104. The corresponding horizontal arm 103b is rested on the base 111 of the channel 110 and is secured in place by bolting washers 105 on top of the horizontal arm 103b and base 111.

The prior art assembly 100 is relatively easy to construct from readily available components and may be considered satisfactory in applications with little loading on the upright 120. However, it has been found that the prior art assembly 100 is vulnerable to extensive deformation and/or damage when the upright 120 experiences lateral loading, e.g. in earthquakes. Damage may result when the forces placed on the steel upright 120 are sufficient to lift the upright 120 away from the channel, e.g. by pivoting about one or more of axes X, Z, Z', and bend the washer 105. The upright 120 may then be loose in position as the bent washer will no longer secure the angle bracket 103 in position. A loose connection between upright 120 and base channel 110 presents a potentially unstable and dangerous structure. Furthermore, any movement of the upright 120 may cause damage to attached wall panels and utilities.

A further problem with the prior art assembly 100 is that the screw 102 connecting the sidewalls of the base 121 to those of the upright 120 may be lifted by the upright 120 to such an extent as to pivot and rip the screw 102 from the sidewall 112.

The assembly 1 of the preferred embodiment of the present invention, as shown in figure 2, is formed from a first member provided in the form of a steel-framing base channel 10 (similar to the base channel 110 of the prior art assembly 100) and has a base 11 and two sidewalls 12 extending therefrom.

Two second members are provided in the form of steel uprights 20 (similar to the uprights 120 of the prior art assembly 100) and each has a base 21 and two sidewalls 22 extending therefrom

The assembly 1 differs from the prior art, in the provision of a plastic anchor 30 that is bolted to the base 11 by bolt 4 and screwed to the sidewalls 12, 22 of the base channel 10 and upright 20. Tek screws 3 are used in the embodiment shown in figure 2 though it will be appreciated numerous types of fastener may be used.

As shown in figures 2 and 3, the anchor 30 also has a base 31 and two sidewalls 32 corresponding with the base 11 , 21 and sidewalls, 12, 22 of the base channel 10 and upright 20. The sidewalls 32 are attached to the upright 20 such that the sidewalls 12, 32 of the base channel 10 and anchor 30 extend in a direction substantially parallel with a longitudinal vertical axis of the upright 20.

The forces placed on the connection 2 between the base channel 10 and upright 20 are dependant on the direction of force and distance from the connection 2. Thus, the greatest forces incident on the connection result from forces applied transverse to the upright 20, rather than those applied parallel to the longitudinal axis. For example, a transverse force 5 will manifest at the connection 2 as a lifting force 6 on one side of the upright 20 as the other side acts as a fulcrum and the upright 20 pivots about axis Z, i.e. the opposing sides respectively experience tensile and compressive forces. The anchor sidewalls 32 extend vertical in a parallel direction to the longitudinal axis Z of the second member. The lifting forces 6 are thus applied as compressive or tensile forces in the planes of the sidewalls 32 or as a flexing force on the anchor 30 about the bolt 4. In contrast, in the prior art assembly 100 (as described above), the horizontal bracket arm 3b extends in a direction perpendicular to the upright 120 and connects the upright 120 to the base 111. Therefore, the lifting forces will be converted to a bending moment on the washer 105 and screws 102.

The sidewalls 22 are positioned between the anchor 30 and base channel 12 sidewalls so that the screws 3 are held in place by not only the base channel sidewalls 112 (as in the prior art) but also the anchor sidewalls 32. The lifting force 6 is applied to the screws 3 as a shear force rather than a bending or pivoting force as in the prior art. Thus, the screws 3 will not bend and rip from the base channel 10.

The thickness of the anchor sidewalls 32 can also be varied to alter the resistance and resilience of the assembly 1. As shown in Figure 3, anchor sidewalls 32 may also include a groove or indentation 33 that allows anchor 30 to easily slip over any screw dimples in the framing. Indentation 33 may be any shape required to suit different fastening means or may be omitted as required.

The plastic anchor 30 also acts as a biasing member to absorb the force 6 and return the anchor 30 and attached upright 20 to its original, stable, equilibrium position when the force 6 is stopped.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Claims

WHAT WE CLAIM IS:

1. A method of construction including the steps of:

providing a first and second members, the second member being elongate; and

attaching an anchor to the first and second members

2. The method of claim 1 , wherein the first member is elongate and has a base and two sidewalls extending from the base.

3. The method of claim 2, wherein the first member is an elongate steel-framing 'base-channel' having a substantially 'U'-shaped cross- section.

4. The method of any one of claims 2 or 3, wherein the first member sidewalls extend substantially parallel with the second member longitudinal axis.

5. The method of any one of claims 1-4, wherein the second member is attached to the sidewalls of the first member.

6. The method as claimed in any one of claims 1-5, wherein the second member is an elongate steel-framing support having a substantially 'U'-shaped cross-section.

7. The method of any one of claims 1-6, wherein the anchor is attached to the sidewalls of the first member.

8. The method of any one of claims 1-7 wherein the anchor is constructed from a substantially resilient material such as plastic.

9. The method of any one of claims 1-8, wherein the anchor has a base and two sidewalls respectively corresponding to the base and sidewalls of the second member, the anchor sized to fit between the second member sidewalls.

10. The method of any one of claims 1-9, wherein the anchor sidewalls are sufficiently flexible to bend with respect to the base.

11. The method of any one of claims 1-10, wherein the anchor sidewalls include at least one groove or indentation to accommodate a fastening means or fixture.

12. The method of any one of claims 1-11 wherein the anchor has a base and four sidewalls.

13. The method of any one of claims 1-12 wherein, the anchor is attached to the base of the first member.

14. The method of claim 13 wherein the anchor is further attached to a structure to which the first member is attached.

15. The method as claimed in any one of claims 1-14, wherein the anchor, first and/or second members are attached together such that the sidewalls of the second member are positioned between the sidewalls of the anchor and first member.

16. The method as claimed in any of claims 1-15 wherein only one end of the second member is attached to the first member.

17. The method as claimed in any of claims 1-16, wherein the anchor, first and/or second members are attached together in a fixed relationship with respect to each other.

18. The method as claimed in any one of claims 1-17, wherein a fastener is used to secure the anchor, first and/or second members together.

19. The method of claim 18 wherein the fastener includes one or more of a bolt, screw, Tek-screw, plug, rod, axle, staple or any other fastener capable of extending through the anchor, first and/or second member sidewalls.

20. A support assembly including:

first and second members, the second member being elongate; and

an anchor attached to the first and second members

wherein the anchor has a base and at least two sidewalls, the sidewalls of the anchor being attached to the second member and extending in a direction substantially parallel with a longitudinal axis of the second member.

21. The support assembly of claim 20, wherein the first member is elongate and has a base and two sidewalls extending from the base.

22. The support assembly of claim 21 , wherein the first member is an elongate steel-framing 'base-channel' having a substantially 'U'-shaped cross-section.

23. The support assembly of any one of claims 21 or 22, wherein the first member sidewalls extend substantially parallel with the second member longitudinal axis.

24. The support assembly of any one of claims 20-23, wherein the second member is an elongate steel-framing support having a substantially 'U'-shaped cross-section.

25. The support assembly of any one of claims 20-24 wherein the anchor is constructed from a substantially resilient material such as plastic.

26. The support assembly of any one of claims 20-23, wherein the anchor has a base and two sidewalls respectively corresponding to the base and sidewalls of the second member, the anchor sized to fit between the second member sidewalls.

27. The support assembly of claim 26 wherein the anchor sidewalls are sufficiently flexible to bend with respect to the base.

28. The support assembly of any one of claims 20-27 wherein the anchor sidewalls include at least one groove or indentation to accommodate a fastening means or fixture.

29. The support assembly of any one of claims 20-27 wherein the anchor has a base and four sidewalls.

30. The method of construction substantially as described herein and with reference to Figures 2 and 3.

31. The support assembly substantially as described herein and with reference to Figures 2 and 3.

32. The anchor substantially as herein before described and with reference to Figures 2 and 3