AU2021103826A4

AU2021103826A4 - Footing system for residential applications

Info

Publication number: AU2021103826A4
Application number: AU2021103826A
Authority: AU
Inventors: Jarrad Telford
Original assignee: Madewell Products Pty Ltd
Current assignee: Madewell Products Pty Ltd
Priority date: 2021-07-02
Filing date: 2021-07-02
Publication date: 2021-09-09
Anticipated expiration: 2029-07-02

Abstract

A footing system for a building construction comprising a concrete slab configured to distribute vertical loads from the building construction to an underlying foundation; and a plurality of reinforcement members positioned to be embedded within the concrete slab; wherein the reinforcement members are arranged to extend within the concrete slab in two vertically spaced apart layers and each of the reinforcement members are formed from a non-metallic material such that the concrete slab is devoid of corrosive components. I 0 _______________ Q -- - - - - - - - - - - - - *u mumu * mum ~1) S - - - - - a.- ---

Description

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FOOTING SYSTEM FOR RESIDENTIAL APPLICATIONS FIELD OF INVENTION

The present invention relates generally to a footing system for residential load applications, and in particular, to a mat slab footing system employing non corrosive components.

BACKGROUND OF THE INVENTION

In construction the footings of a building function to transfer the load from the building to the foundation, namely the supporting ground surface. Most buildings, especially residential houses, employ concrete footings of one type or another, either in the form of slab-on-ground footings or as suspended floors. Concrete is an important material for use in such applications as it offers the flexibility of a structural material that can be cast into almost any desirable shape and size and is durable and able to be adapted to suit a variety of different requirements and specifications found in most building applications.

Footings, and in particular concrete footings play an important role in not only distributing vertical loads from the building to the ground foundation, but also function to ensure that the building superstructure retains its integrity, particularly in instances where the foundation is subject to movement due to environmental changes. As many cities experience an increase in population there is a need to build more houses to cater for the growing population. As a result, many new housing developments are being built on sites that have previously been overlooked as being not ideally suited for construction, due to the soil profile and other factors. This has generated many challenges in the design and creation of concrete footings in such applications.

Prior to construction, it is generally required to perform a geotechnical survey of the site to determine the soil profile. Such a survey will typically establish the soil type, moisture content, bearing capacity and possible reactivity of the soil when subject to climatic conditions likely to occur at that site. The result of the survey and subsequent report will then enable the footing and slab design to commence to comply with the various requirements. If a site is considered a reactive site, it will generally consist of a soil type, such as clay, which will swell when exposed to moisture and shrink when dry. Such movement of the foundation can be of an amount that can damage the footings of the building if not designed correctly, typically causing cracks to form in the footings which can cause the integrity of the footings to become compromised, especially when exposed to moisture and the like.

In residential applications, the most common form of footing is generally the mat or raft slab that comprises a thick concrete slab reinforced with ductile reinforcing. The mat slab design does not generally require deep excavation and the ground surface can be generally excavated to a shallow depth and the concrete can be poured into the excavated cavity, which is contained by building edge formwork. Mat slabs can be used across a variety of soil profiles as they have sufficient thickness, they can accommodate large lateral forces and can span over soft soil areas. In recent times, waffle slabs have been introduced which 1o employ polystyrene or cardboard to form voids in the concrete to produce a close grid of reinforced concrete ribs in the concrete slab, between which slap panels are supported. Such systems require less concrete and reinforcement but require polystyrene pods to form the voids which can create significant wastage and environmental damage.

The mat slabs and waffle slabs are typically reinforced by way of steel trench mesh or bars which are arranged in a grid format to extend within the concrete slab. Whilst such reinforcement bars have proven effective in increasing the strength and load capacity of the slab, they are heavy and require significant cost and labour to carry and install at the construction site. Further to this, should the slab experience cracking, the steel bars can become exposed to moisture that can cause the reinforcement to corrode and can severely compromise the integrity of the footings.

Thus, there is a need to provide a footing system that minimises the use of corrosive components and which employs low weight reinforcement material to provide a footing that can accommodate residential loads in a simple and effective manner. Across a variety of soil profiles.

The above references to and descriptions of prior proposals or products are not intended to be, and are not to be construed as, statements or admissions of common general knowledge in the art. In particular, the following prior art discussion does not relate to what is commonly or well known by the person skilled in the art, but assists in the understanding of the inventive step of the present invention of which the identification of pertinent prior art proposals is but one part.

STATEMENT OF INVENTION

According to a first aspect, there is provided a footing system for a building construction comprising: a concrete slab configured to distribute vertical loads from the building construction to an underlying foundation; and a plurality of reinforcement members positioned to be embedded within the concrete slab; wherein the reinforcement members are arranged to extend within the concrete slab in two vertically spaced apart layers and each of the reinforcement members are formed from a non-metallic material such that the concrete slab is devoid of corrosive components.

In one embodiment the reinforcement members are formed from a composite reinforced polymer material. The composite reinforced polymer material may be a glass fibre reinforced polymer.

The reinforcement members may be configured to have a corrugated outer surface. The corrugated outer surface of the reinforcement members is formed by helically winding a fibres along a length of the reinforcement members.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be better understood from the following non-limiting description of preferred embodiments, in which:

Fig. 1 is a plan view of a footing system for a residential construction in accordance with an embodiment of the present invention;

Fig. 2 is a cross sectional end view of the footing system of Fig. 1; and

Fig. 3 is a side view of a reinforcement member for reinforcing the footing system of Figs 1 and 2.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred features of the present invention will now be described with particular reference to the accompanying drawings. However, it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention.

The footing system of the present invention will be described below in relation to a mat slab arrangement configured to be supported on a ground surface. However, it will be appreciated that the footing system of the present invention could be supported on piers/piles and could be incorporated into a waffle slab or any other type of slab-on-ground arrangement and still fall within the spirit of the present invention.

Referring to Fig. 1, a plan view of a footing 10, such as a mat slab, for a conventional residential dwelling is depicted. The footing 10 is typically mounted directly on a foundation, such as a ground surface, or may be mounted upon screw piles or piers (not shown), as may be dictated by the soil profile of the ground surface. The footing 10 is designed to distribute vertical loads from the building to the ground foundations and is capable of withstanding a degree of lateral movement as may be experienced from time to time.

In the embodiment as depicted, the footing 10 is reinforced by a grid reinforcement 20 made up of interconnected reinforcement members 30, as depicted in Fig. 3. The reinforcement members 30 are formed from a non metallic composite material that is arranged in a grid pattern 20 to extend throughout the concrete slab footing 10. In a preferred from the reinforcement members 30 are formed from a composite reinforced polymer (CRP), such as a Glass Fibre Reinforced Polymer (GFRP) that is extruded into lengths of variable diameters.

The GFRP reinforcement members 30 replace conventional steel rebar that has traditionally been used in reinforcing foundation slabs. The GFRP material is high in strength, lightweight and durable and does not corrode, even in harsh environmental conditions, such as when exposed to water, salt, humidity, high voltage currents and magnetic fields.

The GFRP reinforcement member 30 are considerably lighter than conventional steel rebar, having a specific weight of around 2.2 (g/m3) compared to steel which has a specific weight of around 7.8 (g/m3). Due to the significant weight difference, workers are able to handle the reinforcement members 30 on site in easier manner and with less stress on their bodies. The reinforcement members 30 also have a higher tensile strength of around 800-1000 MPa when compared to conventional steel rebar of around 550 - 800 MPa.

Referring to Fig. 3, the reinforcement member 30 is configured to have a corrugated external surface 32. This is achieved by winding a ribbon 34 of fibres in a helical manner along the length of the member 30 such that the ribbon 34 causes the core fibres that extend longitudinally along the length of the member 30 to bulge outwardly between the ribbons 34. The resultant corrugated surface of the reinforcement member 30 creates an increased bond with the concrete when the concrete is poured over the positioned reinforcement members 30 during formation of the slab 10.

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The reinforcement member 30 may be provided in a variety of diameters, as required by the slab design. In this regard, the diameters may range from 5 mm 35 mm. The individual reinforcement members 30 may be secured together in a grid pattern by way of tie wires having a non-corrosive coating or by wat of polymeric clips and the like to minimise any likelihood of corrosion of the reinforcement materials within the slab.

As is depicted more clearly in Fig. 2, the slab 10 has the reinforcement members 30 configured to extend in an upper and lower grid layer. Due to the increased strength of the reinforcement members 30, the members 30 are able to be spaced apart by a distance 'X' which may vary between 200 - 300 mm, depending upon the specific slab design and the diameter of the members 30 used.

It will be appreciated that due to the lightweight of the reinforcement members 30, the footings 10 are able to be constructed and reinforced in a manner that is easy to handle and transport to site. Such an arrangement ensures that there are no corrosive elements present in the footings, thereby increasing the lifespan of the slab and any future maintenance that may be required. The increased strength of the footings formed using the reinforcement members in a residential application ensures that the foundation of the construction is of a high standard to accommodate a variety of different soil profiles.

Throughout the specification and claims the word "comprise" and its derivatives are intended to have an inclusive rather than exclusive meaning unless the contrary is expressly stated or the context requires otherwise. That is, the word "comprise" and its derivatives will be taken to indicate the inclusion of not only the listed components, steps or features that it directly references, but also other components, steps or features not specifically listed, unless the contrary is expressly stated or the context requires otherwise.

It will be appreciated by those skilled in the art that many modifications and variations may be made to the methods of the invention described herein without departing from the spirit and scope of the invention.

Claims

The claims defining the invention are: 1. A footing system for a building construction comprising: a concrete slab configured to distribute vertical loads from the building construction to an underlying foundation; and a plurality of reinforcement members positioned to be embedded within the concrete slab; wherein the reinforcement members are arranged to extend within the concrete slab in two vertically spaced apart layers and each of the reinforcement members are formed from a non-metallic material such that the concrete slab is devoid of corrosive components.
2. A footing system according to claim 1, wherein the reinforcement members are formed from a composite reinforced polymer material.
3. A footing system according to claim 2, wherein the composite reinforced polymer material is a glass fibre reinforced polymer.
4. A footing system according to any one of claims 1 to 3, wherein the reinforcement members are configured to have a corrugated outer surface.
5. A footing system according to claim 4, wherein the corrugated outer surface of the reinforcement members is formed by helically winding a fibres along a length of the reinforcement members.