AU2002234421B2 - A load bearing building panel - Google Patents

Description

A LOAD BEARING BUILDING PANEL

This invention relates to a load bearing building panel.

This invention has particular but not exclusive application

to a load bearing building panel made predominantly from light

weight concrete which may be used in the construction of

5.' buildings, and wherein reference will be made to same.

Many buildings, including those used as dwellings, are built

upon a foundation comprising a concrete slab. The external walls of the building typically are mounted on the peripheral edges of the concrete slab and may comprise a plurality of timber or metal 0 frames.

The external face of the frames is often concealed behind a suitable form of cladding, such as lengths of timber or panels constructed from light weight composite materials, including light weight concrete, which are fastened to the frames. 5 The internal face of the frames may also be concealed behind

a suitable form of cladding, such as sheets of plaster board,

that are fastened to the frames.

The frames also provide support for a roof structure and

wherein elongate fasteners, known as tie rods, that extend

0 through the frames, are often used to secure the roof structure

directly to the foundation.

It will be appreciated that the aforementioned method of constructing a building is very time consuming and requires the

co-ordination of different suppliers and tradesmen. Delays in

the supply of materials and/or the availability of tradesmen can

add greatly to the cost of the construction of the building. It

is also noted that the quality of workmanship provided by

different tradesmen may vary considerably and thereby may have a detrimental effect on the value of the building.

Other building methods, commonly referred to as "tilt-up

construction", comprise walls manufactured from concrete. These are usually lifted into place on site with the aid of a crane. Accordingly, while such methods of construction may be less time consuming than the more traditional method described above, the handling of heavy walls made of concrete is more hazardous.

One object of the present invention is to provide a load bearing building panel manufactured from a reinforced, light

weight, concrete material which may be used in the construction of external walls of buildings and such like in place of the

various methods of wall construction discussed above. It is envisaged that the load bearing building panel that is the

subject of the present invention will be light enough that it may

be located in position by either two tradesmen or with the aid

of small lifting equipment, such as a bobcat, or other mechanical

apparatus with a lifting arm attachment. Furthermore, the reinforcing in combination with the concrete shall resist imposed

loading such as from roof, lintels and upper floors, and provide

protection against lateral impact loads, such as may occur as a

consequence of acts of vandalism, or due to flying debris during

high wind and cyclonic conditions.

It is also desirous to develop an alternative method of

constructing buildings wherein non load bearing wall panels

manufactured from reinforced concrete may be used in place of the much heavier concrete wall panels that are currently used in tilt-up constructions . With the foregoing in view, this invention in one aspect resides broadly in a load bearing building panel, including: a body composed of a light weight concrete material, said body having an obverse face and an opposing reverse face, and two opposing side faces, said obverse face, reverse face and side faces being located intermediate opposing upper and lower faces;

a first reinforcing contained within said body and located adjacent said obverse face, said first reinforcing extending

through said body in the general direction of said upper and

lower faces for at least much of the length of said body, said

first reinforcing also extending through said body in the general

direction of the side walls for at least much of the width of

said body; a second reinforcing contained within said body and located

adjacent said reverse face, said second reinforcing extending

through said body in the general direction of said upper and

lower faces for at least much of the length of said body, said

second reinforcing also extending through said body in the

general direction of said side walls for at least much of the

width of said body, and wherein said first reinforcing and/or said second reinforcing includes both upper and lower engaging

portions each of which are capable of at least partially extending about a fastener that extends through said body between said obverse and reverse faces.

The body may be any suitable shape. For example, the shape of the body may generally resemble a rectangularly shaped prism

and wherein the obverse and reverse faces, the two side faces, and the upper and lower faces may lie in planes that are substantially parallel. However, it will also be appreciated

that the obverse and reverse faces, and/or the two side faces, and/or the upper and lower faces may lie in planes that diverge.

The size of the body will generally be dependent upon individual job constraints, such as ceiling heights, single or

two story construction, roof loadings, design wind loadings,

manual or machine positioning units, and the like. Nevertheless

it is preferred that the upper and lower faces are each short, (distance separating the opposing side faces which is preferably

much smaller than the distance that separates the upper and lower faces) narrow (distance separating the obverse and reverse faces)

faces that are generally rectangular in shape. It is also

Preferred that the two side faces are two long, (distance

separating the upper and lower faces which is preferably much

greater than the distance separating opposing side faces),

narrow, (distance separating the obverse and reverse faces), faces that are generally rectangular in shape. Similarly it is preferred that the obverse and reverse faces are two long, (distance separating opposing upper and lower faces which is preferably much greater than the distance separating opposing side faces), broad, (distance separating the opposing side faces which is preferably much greater than the distance separating the obverse and reverse faces), faces that are generally rectangular in shape. For example, the length of the body, (distance separating the upper and lower faces), may vary between 1800 mm

and 3600 mm; the width of the body, (distance separating the two

opposing side faces), may vary between 300 mm and 900 mm, and the

depth of the body, (distance separating the obverse and reverse

faces), may vary between 70 mm and 150 mm.

Each face may generally comprise a single surface. By way

of example, the surface may be substantially flat or it may be curved.

Alternatively each face may include a plurality of surfaces. These surfaces may be either substantially flat or curved, or a

combination of both flat and curved surfaces. For example, a face may have a corrugated surface.

The surfaces may have any suitable texture. For example, the

surfaces may be generally rough or smooth, and may be rendered in a decorative manner, such as a surface finish that resembles rows of bricks .

The body may be manufactured from any suitable light weight concrete material including light weight concrete materials of the type that is referred to as "Autoclave Aerated Concrete".

The first and second reinforcing may each comprise a sheet

of a reinforcing material, such as steel. The sheet may include one or more apertures formed therein and wherein these may be arranged in an ordered or a random manner. For example, the reinforcing may resemble a mesh like structure.

Alternatively the first and second reinforcing may each include a one or more elongate reinforcing members manufactured

from a suitable material, such as steel. For example, each

reinforcing may comprise a plurality of rod like reinforcing

members that may be interconnected together, such as by a welding

process or using a plurality of wire ties. For example, rod like reinforcing members in combination with one another may form a

mesh like structure.

In one embodiment, each of the engaging portions may

comprise an aperture or opening formed in the reinforcing. For

example, the engaging portion may comprise an aperture formed in

a sheet of a closed or open material, such as a mesh like

material. Alternatively, each of the engaging portions may comprise a loop or hook like portion of a reinforcing member that

is attached to or forms an integral part of the reinforcing. For example, the attachment of the loop or hook like reinforcing member to the reinforcing may be achieved using a welding process or a plurality of wire ties.

As with panel sizes, steel reinforcement sizes will be dictated by the individual job constraints and the loading imposed.

In another aspect, this invention relates to a method of constructing a building, said method including: the provision of a foundation;

the erection of one or more external walls comprising at

least some of which include a load bearing building panel of the

type described above, and wherein said panel is secured to the

foundation by a fastener that is at least partially surrounded

by a lower engaging portion; the affixing of a floor or a roof structure to said external

wall or external walls, said floor or roof structure being spaced

from the foundation by said external wall or external walls, said

floor or roof structure being secured to said load bearing

building panel by a fastener that is at least partially

surrounded by an upper engaging portion.

In one embodiment, the foundation may include a concrete

slab upon which the building shall be built. The edges of the slab may include a recessed portion that is adapted to receive a lower portion of at least some of the building panels. In such cases, a load bearing building panel may be secured to the concrete slab by a fastener that extends through said panel and which engages with said slab, said fastener being at least partially surrounded by a lower engaging portion of reinforcing contained within the panel. Alternatively, the foundation may include a plurality of

footings, such as a plurality of concrete pillars which may be buried beneath the ground. The footings may be used to provide

support for posts , which themselves support beams that are

suspended above the ground. In such cases, a load bearing

building panel may be secured to a beam by a fastener that

extends through said panel and which engages with said beam, said

fastener being at least partially surrounded by a lower engaging portion of reinforcing contained within the panel.

In another aspect, this invention relates to a load bearing column, said column including:

a base portion that is engageable with a supporting

structure upon which it rests;

a top portion that is engageable with a supported structure that rests upon said top portion, and

a tubular member having a triangularly shaped transverse cross-section having a lower end portion that is attached to said base portion and an upper end portion that is attached to said top portion.

The supporting structure may include a foundation, such as a concrete slab, or a floor of a building. The base portion may

be cast into the slab or floor during construction or alternatively attached thereto using one or more fasteners. The supported structure may include a floor or roof structure of a building. The top portion may be cast into the floor or roof structure during construction or alternatively

attached thereto using one or more fasteners.

The tubular member may be attached to the base member and

the top member using a plurality of fasteners. Alternatively,

the tubular member may be attached to the base member and the top

member using a welding process. Preferably the tubular member is constructed from mild

steel .

In another aspect, this invention relates to a method of

constructing a building including:

providing a foundation;

securing a plurality of triangularly shaped load bearing

columns of the type described above to said foundation, said

columns being adapted to provide support for a roof or floor structure; constructing walls using a plurality of wall panels having lower edge portions that are secured to said foundation and wherein an elongate edge of at least one of the columns is located in a corner formed by adjacent wall panels, and securing upper portions of the wall panels to said roof or floor structure.

The wall panels may be constructed from a variety of materials including reinforced lightweight concrete which may be

non load bearing or of the type previously described above.

In order that this invention may be more easily understood

and put into practical effect, reference will now be made to the

accompanying drawings which illustrate preferred embodiments of

the invention and wherein:

FIG. 1 is a schematic isometric view of a load bearing building panel constructed in accordance with the present

invention;

FIG. 2 is a schematic isometric view of a reinforcing used

in the construction of the load bearing building panel

illustrated in figure 1;

FIG. 3 is a side view of a portion of a single story

building constructed in accordance with the present invention; FIG. 4 is a cross-sectional front view showing part of a

wall of the of the building illustrated in figure 3; FIG. 5 is a detailed isometric view showing a portion of the foundation of the building illustrated in figure 3; FIG. 6 is a side view of a portion of a double story building constructed in accordance with a different aspect o f the present invention;

FIG. 7 is a side view of another double story building constructed in accordance with the invention illustrated in figure 6;

FIG. 8 is a side view of a portion of a single story

building constructed in accordance with the invention

illustrated in figure 6;

FIG. 9 is a perspective view of an upper part of the

building shown in figure 8, and

FIG. 10 is a perspective view of a lower part of the building shown in figure 8.

Figure 1 shows a typical load bearing building panel 10 that

for convenience is broken in the middle. The load bearing

building panel or panel 10 includes a body 11 that generally resembles a rectangular shaped prism.

The body includes an obverse face 12 and an opposing reverse

face 13, as well as two opposing side faces 14 and 15. The

obverse face 12, reverse face 13 and the two side faces 14 and 15 are located intermediate opposing upper and lower faces 16 and 17 respectively.

The body also includes a first reinforcing 18 and a second reinforcing 19. The reinforcing 18 and the reinforcing 19 each comprise two sets of interconnected steel rod like members 20 that are arranged so as to form a mesh like sheet. In particular the two sets of steel rods are arranged such that they are at 90 degrees to each other, one set being substantially parallel to

the edges of the panel 10, the other set being substantially

parallel to the top and the base of the panel 10. Each reinforcing 18 and 19 also includes an upper engagement portion

21 and a lower engagement portion 22.

Each engagement portion 21 and 22 comprises a generally "U"

shaped steel rod 23 that is welded to the mesh like sheet at

points 24 along it's length. By way of example, the "U" shaped steel rod is attached to the internal face of the reinforcing 18

or 19.

Preferably the "legs" 25 of the "U" shaped steel rod 23

overlie the longitudinally extending steel rods from which the

reinforcing is made. For example, the "U" shaped steel rod 23a

may be located approximately 50 mm from the upper face 16 (i.e.

50 mm cover), and overlies 300mm of the reinforcing. Similarly, the "U" shaped steel rod 23b may be located approximately 125mm from the lower face 17 (i.e. 125mm cover).

The body is constructed from a light weight concrete material, such as that which is referred to as "Autoclave Aerated Concrete", and wherein rectangular box shaped waterproof moulds may be used in the construction of same. These are required to hold the lightweight concrete while it sets or cures. Preferably these are capable of individual adjustment in length from 1800mm to 3600mm, in width from 300mm to 900mm, and in depth from 70mm

to 150mm.

The first reinforcing 18 is cast in the panel 25mm to 50mm from the reverse or internal face 14 of the panel. The second

reinforcing 19 is cast in the panel 10 approximately 25 mm to 50

mm from the obverse or external face 13 of the panel. A minimum

concrete cover (i.e. distance from steel to external faces of

concrete) of 30 mm is to be allowed to sides, top and base of panels .

Two metal or plastic sleeves having an internal diameter of

14mm and length varying from 70mm to 150mm, depending on panel

thickness, are preferably cast in the panel to provide for a

through bolt fixing to the top and the base of the panel. These

sleeves are to be located equidistant from the sides of panel, one 75 mm from the centre of sleeve to top of panel, and the

other 150 mm from the centre of sleeve to base of panel. In some panels, a 14mm diameter hole will be cast in the panel in lieu, in the same locations as above and with the same distances from hole centre to top of panel and base of panel.

Having filled the rectangular box shaped mould with a light weight concrete mix, the mix should be allowed to set or cure.

Figures 3, 4 and 5 show a portions of a typical building that comprises load bearing building panels 10 of the type described above.

The building includes a foundation 30 consisting of

reinforced concrete footings 31 and a slab 32 which are laid in accordance with standard building practice, with a 310 mm high

x sheet thickness plus 10mm wide step down formed around the full perimeter of the building. A 10mm thick leveling bed of mortar

is laid over a damp proof course to the horizontal surface of

this step down, and for the full perimeter of the building. The reinforced lightweight concrete wall panel 10 is located

and fixed with a proprietary adhesive to the leveling bed and

temporarily propped as per conventional building practice. Then

the panel 10 is bottom fixed with a single M12 stainless steel

Trubolt 33 through the cast in metal or plastic sleeves, or 14mm

diameter hole, and fixed 125 mm into slab face as illustrated in

figure 3. The 10mm PCV packer 35 must be located over the Trubolt 33 prior to tightening.

Another reinforced lightweight concrete panel is then

similarly located in place beside the first and vertical edge fixed to preceding panel with a proprietary adhesive, and in accordance with manufacturer's specification. Panel is then bottom fixed as per first panel. This procedure is continued

around the building's perimeter until all of the external walls are completed.

Window and door openings are constructed preferably using

standard reinforced lightweight concrete lintels, having 450 bearing each end and M12 tie down rods each side of openings.

Over wider openings, e.g. double garage door openings, domestic

steel-framed lintels are to be used with FC cladding externally

to accept render finish.

When the panel bedding joint and vertical joint adhesive has

set, interior domestic steel-framed bracing walls are to be installed at intervals not exceeding 9.0 to facilitate removal

of temporary props. Liquid grout is then poured into the 10mm gap

between case of wall panels and concrete slab to bond the two

components together, which provides added strength.

A steel top plate 36 is now fixed in place by fasteners 37 to provide continuity of tie down to roof framing. The roof

structure 38 in turn is secured to the top plates as illustrated.

Expansion or control joints are preferably placed at approx'

6.0 centres for the full perimeter of the reinforced lightweight concrete wall panels .

It will be appreciated that the light weight panels 10 may be located in place by two men or a bobcat and accordingly overcome some of the problems associated with tilt-up construction. Further, it will be appreciated that the method of construction described above is less labor intensive than more

conventional methods of construction.

It will also be appreciated that the use of light weight

concrete in the construction of the load bearing panels lessens

the loading on the footings or lower structure of the building.

Figures 6 to 10 illustrate an alternative method of

constructing buildings that includes a load bearing steel frame

to which cladding, comprising lightweight concrete panels has

been attached thereto. With particular reference to figure 6, the building includes

a foundation 110, comprising a concrete slab 111 having

peripheral edge portions 112 in which there is formed a stepped

recesses 113.

During the pouring of the concrete slab 111, a hollow extruded section 114, having a tapered cross-sectional shape, may

be set into a vertical wall 115 of the recess 113. Preferably

the extruded section is manufactured from allu inium or zincallum.

Base plates 116 manufactured from mild steel, and having a plurality of dependent projections 117 are preferably set into

the concrete slab 111, at the time when the slab is poured. Preferably the base plates 116 are located on the slab 111 where it is desirous to place a load bearing steel column 118, such as

the corners of the slab 111, as illustrated in Figure 10, or where an internal wall 119 shall be located.

The columns 118 are each manufactured from lengths of hollow

extruded mild steel 123 and wherein the cross-sectional shape of

the sections generally resembles an equilateral triangle having

elongate rectangularly shaped side faces 120, 121 and 122.

The lower portion 124 of each extrusion 123 is preferably

welded to a corner portion of a respective, rectangularly shaped,

base plate 116. The upper portion of each extrusion 123 is preferably welded

to a corner portion of a respective, rectangularly shaped, top

plate 125, that is preferably manufactured from mild steel.

Selective free upper ends of the columns 118 may be

interconnected by "L" shaped metal lintels 126, as illustrated in

figures 8 and 9, and wherein the lintels are used to support a roof structure 127.

The exterior of the building is preferably clad with wall

panels 130 constructed from reinforced lightweight concrete. The lower edge portions of the panels preferably locate within a suitable recess 113 formed in the slab 111 and are attached thereto by fasteners 131, not shown, that extend through the panel and engage with the section 114. The upper edge portions of the panels 130, in the case of a single story building, are secured to the upper ends of adjacent columns 118 using

fasteners, not shown, that extend through the panel and engage with the column. In the case of a multi story building, the

upper edge portions of the panels 130 may be secured to frame

members 132 used to support flooring.

Preferably converging wall panels that form a corner of the

building each abut an opposing side face of an adjacent column

118, as illustrated in figure 9, and if desired, may be attached

thereto. Similarly, wall panels, whether they be constructed from

reinforced concrete or from other materials, that are used in the

construction of internal walls which converge to form a corner

each abut an opposing side face of an adjacent column 118, and

if desired, may be attached thereto.

Figure 7 shows a building that has been constructed in a

manner similar to that illustrated in figures 6, 8, 9 and 10 but wherein the foundation comprises several concrete footings 140 buried in the ground and pillars 141, mounted on said footings 140, upon which a frame 142 that supporting flooring 143 rests.

It will of course be realised that while the foregoing description has been given by way of example of this invention, all other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within

the broad scope and ambit of this invention as described and claimed herein.

Claims (6)

1. A load bearing building panel, including:

a body composed of a light weight concrete material, said

body having an obverse face and an opposing reverse face, and two

opposing side faces, said obverse face, reverse face and side

faces being located intermediate opposing upper and lower faces; a first reinforcing contained within said body and located

adjacent said obverse face, said first reinforcing extending through said body in the general direction of said upper and lower faces for at least much of the length of said body, said

first reinforcing also extending through said body in the general direction of the side walls for at least much of the width of said body; a second reinforcing contained within said body and located adjacent said reverse face, said second reinforcing extending

through said body in the general direction of said upper and lower faces for at least much of the length of said body, said

second reinforcing also extending through said body in the

general direction of said side walls for at least much of the

width of said body, and wherein said first reinforcing and/or

said second reinforcing includes both upper and lower engaging

portions each of which are capable of at least partially

extending about a fastener that extends through said body between said obverse and reverse faces.

2. A load bearing panel as claimed in claim 1, wherein said

first reinforcing and said second reinforcing are each sheet like

and wherein each sheet includes a plurality of apertures formed

therein and whereby one of said apertures constitutes said

engaging portion.

3. A load bearing panel as claimed in claim 2, wherein said first reinforcing and said second reinforcing each consist of a mesh like structure and said engaging portion includes a loop like reinforcing member that is attached to said mesh like structure.

4. A method of constructing a building, said method including:

the provision of a foundation;

the erection of one or more external walls comprising at least some of which include a load bearing building panel of the

type claimed in any one of claims 1 to 3, and wherein said panel

is secured to the foundation by a fastener that is at least

partially surrounded by a lower engaging portion;

the affixing of a floor or a roof structure to said external

wall or external walls, said floor or roof structure being spaced from the foundation by said external wall or external walls, said

floor or roof structure being secured to said load bearing

building panel by a fastener that is at least partially

surrounded by an upper engaging portion.

5. A load bearing column, said column including:

a base portion that is engageable with a supporting structure upon which it rests ;

a top portion that is engageable with a supported structure that rests upon said top portion, and a tubular member having a triangularly shaped transverse cross-section having a lower end portion that is attached to said

base portion and an upper end portion that is attached to said top portion.

6. A method of constructing a building including:

providing a foundation; securing a plurality of triangularly shaped load bearing

columns of the type defined in claim 5 to said foundation, said

columns being adapted to provide support for a roof or floor

structure;

constructing walls using a plurality of wall panels having

lower edge portions that are secured to said foundation and wherein an elongate edge of at least one of the columns is

located in a corner formed by adjacent wall panels, and

securing upper portions of the wall panels to said roof or

floor structure.