AU2018101021B4

AU2018101021B4 - Formwork and reinforcement for a suspended concrete slab

Info

Publication number: AU2018101021B4
Application number: AU2018101021A
Authority: AU
Inventors: Ian Jackson
Original assignee: Iavilaer Pty Ltd
Current assignee: Iavilaer Pty Ltd
Priority date: 2018-04-30
Filing date: 2018-07-24
Publication date: 2019-03-07
Anticipated expiration: 2026-07-24
Also published as: AU2018101021A4

Abstract

Abstract A suspended slab is formed within decking. The decking is arranged with reinforcement in both longitudinal and transverse directions. The reinforcement is fixed relative to the decking before it is raised into position during building construction.

Description

“FORMWORK AND REINFORCEMENT FOR A SUSPENDED CONCRETE SLAB”

Field of the Invention [0001] The present invention relates to multi-storey buildings employing suspended concrete slabs between floors.

Background to the Invention [0002] The pouring of suspended concrete slabs in multi-storey buildings is of crucial importance to the building’s strength and stability. The generally used technique for creating such a slab is time consuming. It involves the creation of appropriate formwork, supported by frames and props underneath; the location and suspension of appropriate reinforcing material; the supply of concrete into the formwork and the smoothing and levelling of concrete by skilled workers.

[0003] Frequently, these operations are required to be performed well above ground level, adding significant safety risks and additional time to the procedure.

[0004] It is known to use pre-formed decks as a basis for the framework, in order to speed the creation of a slab.

[0005] The present invention is based on the realisation that if more construction can be done in a safe, accessible environment (for instance, on a factory floor) and less on-site, this will lead to both significant safety benefits and also provide a dramatic reduction in build-times.

Summary of the Invention [0006] According to one aspect of the present invention there is provided a method of creating a suspended concrete slab, the method including the steps of:

providing decking which extends in a longitudinal direction;

2018101021 24 Jul 2018 providing a plurality of primary reinforcing members above the decking, the primary reinforcing members extending in a transverse direction;

providing a plurality of secondary reinforcing members suspended beneath the primary reinforcing members, the secondary reinforcing members extending in the longitudinal direction;

raising the decking with associated primary and secondary members to a desired location above support means; and pouring concrete into the decking to form a slab encompassing the primary and secondary reinforcing members.

[0007] Preferably the method includes the additional step of overlaying the primary reinforcing members with reinforcing mesh before the decking is raised to the desired locations.

[0008] The steps of providing decking; providing primary reinforcing members; providing secondary reinforcing members and overlaying with reinforcing mesh may be performed in a remote location.

[0009] The primary reinforcing members may be truss girders, such as those manufactured by Australian Steel and Wire Pty Ltd.

[0010] The secondary reinforcing members may be formed from reinforcing bar, such as 16mm reinforcing bar.

[0011] The reinforcing mesh may be SL92 or SL82 reinforcing mesh or similar.

[0012] It is preferred that the decking has a width in the order of 2.4m, and a length greater than 6m. The length may be in the order of up to 12m.

Brief Description of the Drawings [0013] It will be convenient to further describe the invention with reference to preferred embodiments of the present invention. Other embodiments are possible, and consequently the particularity of the following discussion is not

2018101021 24 Jul 2018 to be understood as superseding the generality of the preceding description of the invention. In the drawings:

[0014] Figure 1 is an upper perspective of longitudinally extending decking as used in the method of the present invention;

[0015] Figure 2 is a schematic side view of a truss girder as used in the method of the present invention;

[0016] Figure 2a is a schematic end view of the truss girder of Figure 2;

[0017] Figure 3 is a cross section of the framework for a suspended concrete slab formed in accordance with the method of the present invention, shown before the concrete is poured; and [0018] Figure 4 is a cross section of a concrete slab formed in accordance with the present invention, shown after the concrete is poured.

Detailed Description of Preferred Embodiments [0019] Referring to the Figures, Figure 1 shows a decking member 10 for a suspended concrete slab, the decking member 10 including a plurality of open channels 12. The channels 12 extend in a longitudinal direction 14, perpendicular to a transverse direction 16.

[0020] The channels 12 typically have a width of about 200mm, and a height of about 54mm.

[0021] Figures 2 and 2a show schematically a primary reinforcing member, being a truss girder 20. The truss girder 20 is generally triangular in cross section, with a height of about 110mm and a width of about 70mm. The truss girder 20 has a length of about 2.4m.

[0022] The truss girder 20 has a lower edge 22 and an apex upper edge 24.

2018101021 24 Jul 2018 [0023] The method of the present invention is to provide a framework for a suspended slab formed from a plurality of decking members 10 arrayed laterally; that is, side-by-side in the transverse direction. The decking members 10 are arrayed to form a framework with a longitudinal length of up to 12m and a transverse width of about 2.4m.

[0024] Truss girders 20 are arranged across the top of the decking members 10. The truss girders 20 are oriented in the transverse direction, and thus extend from one side of the framework to the other. Truss girders 20 are spaced from each other in the longitudinal direction, with a spacing of about 900mm between adjacent truss girders 20.

[0025] Secondary reinforcing members formed by reinforcing bar (rebar) 30 extend through the framework in the longitudinal direction. The rebar 30 is arranged so that an individual rebar (typically 16mm) extends within each channel 12 of the decking 10 from one end to the other. The rebar 30 is fixed to the lower edges 22 of the truss girders 20 by suitable means, such as spot welding.

[0026] Once the truss girders 20 and the rebar 30 are fixed in position, an additional layer of reinforcing mesh 32 can be laid atop the truss girders 20. The reinforcing mesh is typically SL92 or SL82 reinforcing mesh. It is secured to the apex upper edges 24 of the truss girders 20 by suitable means, such as spot welding.

[0027] It will be appreciated that this framework, in the order of 2.4m wide by up to 12m long, is both rigid and relatively lightweight. It can be readily transported by road on appropriate vehicles, and can be raised by crane into an appropriate position on a building site above supporting columns 40.

[0028] Once the framework has been located in position atop the supporting columns 40, concrete 42 can be poured into the framework to a depth of about 200mm to 250mm. The concrete can then cure to produce a

2018101021 24 Jul 2018 suitable suspended slab, reinforced in both longitudinal and lateral directions.

[0029] It will be appreciated that a plurality of formwork sets can be produced off-site, transported in a stacked form, and then laid side-by-side to form the framework for a suspended slab. A typical slab section formed in this way may be in the order of 500m², which is considered a reasonable expanse of concrete to be poured in a single day.

[0030] Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

Claims

Claims

1. A method of creating a suspended concrete slab, the method including the steps of:

providing decking which extends in a longitudinal direction;

providing a plurality of primary reinforcing members above the decking, the primary reinforcing members extending in a transverse direction, the primary reinforcing members being truss girders which are generally triangular in cross section;

providing a plurality of secondary reinforcing members suspended beneath the primary reinforcing members, the secondary reinforcing members extending in the longitudinal direction;

providing a reinforcing mesh overlaying the primary reinforcing members;

raising the decking with associated primary and secondary members to a desired location above support means; and pouring concrete into the decking to form a slab encompassing the primary and secondary reinforcing members.
2. A method of creating a suspended concrete slab as claimed inClaim 1, wherein the secondary reinforcing members are formed from reinforcing bar.
3. A method of creating a suspended concrete slab as claimed in any preceding claim, wherein the decking has a width in the order of 2.4m.
4. A method of creating a suspended concrete slab as claimed in any preceding claim, wherein the decking has a length greater than 6m.
5. A method of creating a suspended concrete slab as claimed in claim 4, wherein the decking has a length of about 12m.