FIELD

[0001] The present invention relates to a building element and in particular, a building element for a structural system for formwork.

BACKGROUND

[0002] Concrete is a popular material in the construction industry as it is durable and readily available. Concrete also has desirable properties for use under compression loading. Also, under bending loads, the tensile strength of the concrete is assisted by steel reinforcement that is cast inside the concrete mix or by external steel sections that are connected to the concrete creating what is known as a composite structure.

[0003] Another popular material in the construction industry is steel. Steel is durable and readily available. Elongate structural members such as I-beams, C-beams and the like are commonly used due to their structural rigidity and ability to resist bending forces.

[0004] Concrete, either pre-cast, cast-on-site, pre-tensioned, or the like, generally requires extensive reinforcement to manage non-compression loading (i.e. when forces are applied that do not result in compression, such as a bending force). This results in more time spent during the casting stage increasing the cost of the building project. Corrosion of the steel reinforcement in the concrete may cause what is known as concrete cancer, which is detrimental to the integrity of the concrete structure. Another disadvantage of existing systems is that some time after the concrete has been poured, the formwork on which the concrete was cast needs to be removed and taken away for disposal.

[0005] It is an object of the present invention to substantially overcome, or at least ameliorate one or more of the above disadvantages. SUMMARY OF INVENTION

[0006] An aspect of the present invention provides a building element for a structural system, the building element comprising: a first elongate beam formed to have a base and two sides, the two sides extending away from the base to generally define a C-shape profile; a second elongate beam having a C-shape profile substantially the same as the first beam; and a third elongate beam having a C-shape profile substantially the same as the first beam; wherein, the second and third beams are arranged such that an opening of the C-shape profile of each beam are in an opposing facing relationship, said second and third elongate beams being connected to the first beam.

[0007] Preferably, the first, second and third beams are identical.

[0008] Preferably, the opening of each C-shaped profile is a channel defined by the base and two sides.

[0009] Preferably, at least a part of the second and third beams is located within the channel of the first beam.

[0010] Preferably, a side of each of the second and third elongate beams is attached to the base of the first elongate beam.

[0011] Preferably, the first, second and third beams are made from steel.

[0012] Preferably, the second and third elongate beams are fastened to the first elongate beam by welding, preferably intermittent welding.

[0013] Preferably, the second and third elongate beams are fastened to the first elongate beam by one or more fasteners.

[0014] Preferably, the second and third elongate beams are connected to each other by the first elongate beam and one or more crossmembers attached to the side opposite the first elongate beam. [0015] Preferably, the crossmembers are welded or fastened using one or more bolts to the second and third elongate beams.

[0016] In use, concrete is poured into the channels of the first, second and third beams to improve the tensile strength structure of the concrete once the concrete hardens.

[0017] Another aspect of the present invention provides a method of constructing a formwork system comprising the steps of: laying one or more building elements according to claim 1 on one or more corresponding supports at a predetermined location; positioning a first formwork layer to be supported by the one or more building elements; positioning a second formwork layer on top of the first formwork layer; pouring concrete over the formwork layers and into the channels of the building element.

[0018] Preferably, the first and second formwork layers are supported by at least one of the sides of the first elongate beam of the building element.

[0019] Preferably, the building element and formwork system form a composite structure without the requirement of formwork removal.

BRIEF DESCRIPTION OF DRAWINGS

[0020] Preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings.

[0021] Figure 1 shows a building element according to an embodiment.

[0022] Figure 2 shows a cross-section of the building element of Figure 1.

[0023] Figure 3 shows an end view of a first elongate beam of the building element of Figure 1

[0024] Figure 4 shows a structural system comprising the building element of Figure 1. [0025] Figure 5 shows a building element according to an alternative embodiment.

[0026] Figure 6 shows a building element according to another alternative embodiment.

DESCRIPTION OF EMBODIMENTS

[0027] Figures 1 to 3 show a building element 10 according to a first embodiment. Figure 4 shows the building element 10 in use in an embodiment of a structural system 100.

[0028] Referring specifically to Figure 1, the building element 10 comprises a first elongate beam 20. The first elongate beam 20 has a base 22 and two sides (or flanges) 24, 26. As shown in Figure 1, and more clearly in Figure 2, the first elongate beam 20 has a generally C-shape profile 28. It is envisaged that the first elongate beam 10 is made from steel or other suitable material for supporting loads. Any grade of steel could be utilized.

[0029] Figure 1 also shows a second similar elongate beam 30 having a base 32 and two sides (or flanges) 34, 36. The second elongate beam 30 has a generally C-shape profile 38 that is substantially the same as the first beam 20.

[0030] A similar third elongate beam 40 is also shown in Figure 1. The third beam 40 has a base 42 and two sides (or flanges) 44, 46 defining a C-shape profile 48. Best seen in Figure 2 is a lip 12 which is common to each of the beams 20, 30 and 40. The beams 20, 30, 40 could be identical in shape and/or size or slightly different depending upon construction needs.

[0031] Each of the elongate beams 20, 30, 40 have an opening 29, 39, 49 and a channel 27, 37, 47, defined by the respective base and sides of each beam. The second beam 30 and the third beam 40 are arranged such that the openings 39 and 49 face each other and thus, the beams 30 and 40 are in an opposing facing relationship defining a gap 52. The gap 52 may be any size that corresponds to the ratio of the beams 20, 30, 40. In this configuration, the beams 30 and 40 are fastened to the first beam 20 by a suitable means, preferably by welding or by using one or more fasteners such as bolts. As shown in Figures 1 and 2, the beams 30 and 40 are fastened to the first beam 20 such that the beams 30, 40 are at least partly located within the channel 27 of the first beam 20. The beams 20, 30 and 40 are preferably fastened to each other by welding, however other suitable fasteners may be used such as, for example bolts. When welding, the sides 34, 44 are welded to the base 22. Similarly, or optionally, the sides 24 and 26 at lip 12 are welded to the base 32 and 42 respectively. When the beams 20, 30 and 40 are fastened together, the overall profile becomes a boxed double T-shape, as shown in Figure 2. Additionally, an open cavity 50 is formed by the sides 34, 36, 44 and 46 of beams 30, 40 and the base 22 of beam 20. The sides of the beams 20, 30, 40 are otherwise known as purlins. The purlin of beams 30 and 40 is vertical with respect to the purlin of beam 20 which is horizontal.

[0032] Figure 3 shows an end view of the first elongate beam 20, which is preferably identical in overall size and shape to the second and third beams 30, 40. In Figure 3, the beam 20 is dimensioned to indicate the base 22 and sides 24, 26, the opening 29 of the C-shape profile 28 and the channel 27. Also indicated is the height ‘h’, the side lengths ‘bl’ and ‘b2’, the thickness f and the length of the lip ‘a’. The length of ‘h’ is at least two or more times greater than the length of ‘bl’ or ‘b2\ The height ‘h’ may be from 100mm to 450mm, depending on the structural or aesthetic requirements of the building element 10.

[0033] Figure 4 shows a structural system 100 utilising building elements 10 as described above. The building elements 10 are shown with a first formwork layer 110 and a second formwork layer 120 on top of the first formwork layer 110. Also shown is a layer of concrete 130 on top of the formwork layers 110, 120. The concrete layer 130 also fills in the cavity 50 of the building element 10. The formwork layers 110, 120 rest on top of flange of the building element 10.

[0034] Figure 5 shows the building element 10 according to an alternative embodiment. The building element 10 is shown to have external intermittent welds 65 to join base 42 and side 46, shown in red. A continuous weld may also be used. Figure 5 also shows a plurality of crossmembers 60, in the form of steel plates, welded to the building element 10. The number of crossmembers 60 welded to the element 10 will depend on the length of the element 10 required for the specific application. It is envisaged that the crossmembers 60 add further rigidity to the elongate beam.

[0035] Figure 6 shows the building element 10 according to a further alternative embodiment. The element 10 is the same as described above, however instead of intermittent welds or continuous welds, a plurality of bolts 66 are used to connect the beams 20, 30, 40 together. Not all bolts have been numbered so as to maintain clarity of the drawing. As shown in Figure 6, the bolts 66 connect the base 22 of beam 20 with the side / flange 34, 44 of beams 30, 40. Also, the bolts 66 connect the side / flange 24, 26 of beam 20 with the base 32, 42 of beams 30, 40, respectively. Also shown is a strap 68, which is envisaged to also be a C-shaped profile or even a fourth beam, which connects a portion of the beams 30, 40 together, the portion that is substantially outside of the channel defined by beam 20. This serves to increase the structural rigidity of the building element 10 or provide a carry handle. There may be a plurality of straps 68 depending on the required length of the building element 10.

[0036] Use of the preferred embodiment of the invention will now be described.

[0037] One or more building elements 10 are placed or secured to a support (not shown) located at each end of the building element 10. The support may be any type of wall, beam, lintel and/or column. The first formwork layer 110 is placed between the building elements 10 such that respective ends (not numbered) of the layer 110 are supported by the side (flange) and/or lip of the first elongate beam 20. The second formwork layer 120, if required, is placed on top of the first formwork layer 110. In this manner, the second formwork layer 120 is supported by the first layer 110. The first and second formwork layers 110, 120 may be any type of section, plank or sheet of timber, steel, plastic, polystyrene, fiber cement, or other material suitable for the intended use of the concrete slab. In other embodiments, there may be only one formwork layer, or there may be more than two formwork layers. The lip 12 provides an additional surface contact for welding to base 32 and 42. The lip 12 also provides better adhesion between beams 30 and 40 and the fresh concrete casted inside the building element 10.

[0038] Concrete is poured over the formwork layers 110, 120, as well as into the cavity 50 of the building element 10 and allowed to set. This provides a composite structure with the concrete poured and cast on top of the formwork layer.

[0039] It therefore follows that a method of constructing the formwork system 100 comprises the steps of: laying one or more building elements 10 on one or more corresponding supports at a predetermined location; positioning the first formwork layer 110 to be supported by the one or more building elements 10; positioning the second formwork layer 120 on top of the first formwork layer 110; and pouring concrete 130 over the formwork layers 110, 120 and into the channels 37, 47 and openings 39 and 49 or cavity 50 of the building element.

[0040] Advantages of the preferred embodiment will now be described. [0041] The formwork system 100 together with the building element 10 are able to support the tensile stresses of the concrete slab. Casting the concrete into the building element 10 (i.e. in the cavity 50) provides additional tensile strength. The system 100 is a composite structure that requires only minimum reinforcement in the concrete slab 130 between the building elements 10

[0042] The formwork system 100 together with the building element 10 becomes a permanent structural system that does not require removal and disposal of the formwork.

[0043] Another advantage is that the building elements 10 can be handled, stored and readied for transportation immediately after fabrication. This provides a lightweight pre-cast product. Further, the building elements 10 are lightweight and fast to install, meaning minimum unskilled labor is required.

[0044] Additionally, the formwork system 100 together with the building element 10 reduces installation times when compared to traditional formwork due to the fact that it requires minimum temporary propping.

[0045] The formwork system 100 together with the building element 10 and the concrete mix 130 is versatile, ecologically friendly, and has excellent structural strength, durability, thermal and noise insulation properties.

[0046] The crossmembers 60 and/or strap 68 of the alternative embodiments serve to prevent the beams 30, 40 separating from each other when concrete is poured into cavity 50 of the building element 10. The crossmembers 60 allow a steel reinforcement cage or the like to be welded to the building element 10 if reinforcement is required. Further, the crossmembers 60 and/or strap 68 provide a place for users to carry the building element 10 (i.e. it is like a handle).

[0047] The preferred embodiment of the present invention has been described in a non limiting manner and the general inventive concept may be encompassed in other forms.