AU704885B2

AU704885B2 - Flooring system

Info

Publication number: AU704885B2
Application number: AU40021/97A
Authority: AU
Inventors: Jacek Blum
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-11
Filing date: 1997-10-10
Publication date: 1999-05-06
Anticipated expiration: 2017-10-10
Also published as: AU4002197A

Description

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TITLE

FLOORING SYSTEM FIELD OF THE INVENTION The present invention relates to a flooring system particularly, although not exclusively, envisaged for use in the construction of suspended floors predominantly without the need for erecting and removing formwork.

The invention will hereinafter be described with particular reference to the construction of two storey buildings, although it is to be understood that it can also be used for single storey suspended slab buildings having more than two storeys.

In some cases props are required (for longer spans) and in relation to perimeteral beams a small amount of demountable formwork may be used. Although, an appropriately shaped pre-fabricated end slab could be used.

BACKGROUND OF THE INVENTION It is known to use prestressed concrete beams placed at regular intervals along supports for a suspended slab construction with planar sheets located between the beams to constitute formwork. The sheets remain in place for the life of the floor and so can be considered as permanent formwork. The disadvantage of this form of construction is that the planar sheet cannot withstand very high construction point loadings and hence the beams must be placed at closed centres to accommodate this shortcoming. The sheets are typically hardiplank which has no fibres nor reinforcement and so fails abruptly and without warning. Also hardiplank does not form a substantially monolithic structure with concrete and so ultimately the hardiplank adds to the mass of the floor and adds very little to the strength of the floor. Only concrete and steel (or other concrete compatible materials) ultimately add to the strength of the floor.

It is also known to use an arched formwork modules between the beams. The arching of the formvork modules has the advantage that it increases the construction point loading of the formwork modules. This form of construction of a floor is shown in the book General Building, Dr eng. Wactaw Zenczvkowski, Warsaw (Poland), Building and Architecture 1956, and Australian Petty Patent 653697 (STODULKA).

The main disadvantage of this type of construction is that a crane is required to lift the beams, and the planar sheets into place.

I have developed a flooring system which has permanent formwork which does not require lifting machinery (that is, it can be lifted by hand), becomes integral with the poured concrete to form a monolithic structure which can handle vertical as well as lateral and dynamic loads (and vibration in seismic areas) and can be produced on site. The permanent formwork is operative during construction and remains operative once the concrete has cured adding strength to the flooring.

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S •SUMMARY OF THE INVENTION S .i Therefore it is an object of the present invention to provide a flooring system which uses ••permanent formwork which forms a composite yet substantially monolithic structure with the remainder of the floor once the concrete has been poured and cured.

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e: In accordance with one aspect of the present invention there is provided a flooring system including: *o :"20 a plurality of support beams being arranged substantially parallel to each other and S0 suspended between footings or walls of a building, each support beam having a longitudinally S. extending cavity, each cavity being able to receive and hold concrete during a pour; and a plurality of flooring slabs, the flooring slabs being supported by and extending between adjacent support beams to provide permanent formwork in conjunction with the 0 eo25 support beams, the flooring slabs having a plurality of mechanical keys on upper surfaces thereof which provide a mechanical bond with the concrete pour such that the flooring slabs 4 form a monolithic structure with the support beams once the concrete has been poured over the flooring slabs and the support beams.

In accordance with another aspect of the present invention there is provided a method of constructing a suspended floor, the method including steps of: preparing a support structure for the suspended floor, such as a footing or walls, locating a plurality of support beams between the footings or walls, the support beams being spaced from and substantially parallel to one another upon the support structure; each beam having a longitudinally extending cavity, each cavity being able to receive and hold concrete during a pour; supporting a plurality of flooring slabs between each adjacent support beam to form permanent formwork in conjunction with the support beams to receive the poured concrete, the flooring slabs having a plurality of mechanical keys on upper surfaces thereof which provide a mechanical bond between the concrete pour and the flooring slabs; and .*0SO~ pouring the concrete over the flooring slabs and the support beams, the concrete, once cured, forming a monolithic structure with the flooring slabs and the support beams.

Preferably, the support beams and the flooring slabs are made of concrete or the like material .9-VV which is capable of forming a composite yet substantially monolithic structure with a al* concrete pour once cured.

Typically, each of the flooring slabs is dimensional so as to be able to be lifted and placed 0909 *20 manually so as to obviate the need for cranes and the like.

Typqically, the support beams and the flooring slabs each have mechanical keys for preventing S% longitudinal movement under load between the concrete pour and the flooring slabs and support beams. The mechanical keys provide a

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non-vertical load and dynamic load capability to the complete flooring system. The mechanical keys have the advantage that even in theevent that the bond between the concrete pour and the flooring slabs is lost the mechanical keys maintain a connection between these two components.

Typically, reinforcing mesh is placed above the flooring slabs to prevent the surface of the concrete pour from developing cracks due to shrinkage and to increase the strength of the floor once completed. Reinforcing rods can also be located, when needed to provide increased load capability, in the cavities in the beams prior to the pour.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of examples, with reference to the accompanying drawings in which:- Figure 1 is an upper perspective cut-away view, of a flooring system in accordance with the present invention; Figure 2 is a cross-sectional side view of the flooring system of Figure 1; Figure 3 is a cross-sectional side view showing a close up of a support beam of Figure 2; Figure 4 is a plan view of the flooring system of Figure 1, shown with only one flooring slab prior to pouring concrete, the section A-A is the cross section shown in Figure 2; Figure 5 is a cross-sectional view of a distributing rib of the flooring system of Figure 1; Figure 6 is a cross-sectional side view of the flooring system of Figure 1 including a perimeteral beam; .oo o go gr• a

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a a Figure 7 is a perspective view of the flooring system of Figure 1 including a perimeteral beam; and Figure 8 is a cross-sectional side view of a flooring slab of along the section B-B of Figure 4.

DESCRIPTION OF THE INVENTION In Figure 1 there is shown a flooring system 10 in accordance with the present invention. The flooring system 10 includes a plurality of beams 12 and a plurality of flooring slabs 14 upon which is poured concrete 16. The flooring system 10, in this exemplary embodiment is supported upon a wall 18 made from bricks.

Referring to Figure 2, the beams 12 are formed from a pair of elongate beam halves 20 which typically are of identical shape so that they can be made in the same mould. The beam halves 20 are shaped to form a cavity 22 between when they are placed longitudinally juxtaposed (also see Figure In the present embodiment the beam halves 20 are substantially L-shaped.

Referring to Figure 3, the beam halves 20 each have a head 30 and a foot 32. The foot 32 is intended to be located upon the wall 18 (as shown in Figure 1) and the head is intended to be disposed uppermost with respect to the foot 32. The head 30 has a flange 36 which is located along the length of the head 30. The foot 32 extends laterally from the beam half 20 further the flange 36, so that when the pair of beam halves 20 are brought into longitudinal juxtaposition the two feet 32 meet and there is a gap 34 formed between the two heads. The flange 36 is disposed so that the gap 34 is narrower than the widest extent of the cavity 22 which is indicated by double headed arrow 38.

When the concrete pour 16 is cured in place the cavity 22 is filled with concrete. The concrete pour 16 sets in intimate contact with the pairs of beam halves 20 and 6* 6

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0 5S5* becomes a single monolithic structure. Hence, it can be considered that each of the beams 12 consists of one of the pairs of beam halves 20 and the concrete which sets in the corresponding cavity 22.

Typically, the head 30 of each of the beam halves 20 also has a plurality of periodically spaced mechanical keys 40. The beam mechanical keys 40 are disposed on top of the head 30 (that is, substantially perpendicular to the flanges 36).

The external shape of the beams 12 is typically rectangular so as to allow other constructional elements to be conveniently fixed to them as desired. For example, ceiling panels 58 as shown in Figure 2.

The flooring slabs 14 are typically substantially square when viewed in from the side.

Typically, the flooring slabs are about 470 mm by 460 mm by 29 mm giving a mass of about 16 kg so they can be handled manually without the need for lifting equipment.

The flooring slabs 14 could be simple rectangular prisms in shape. However, it is preferred that the flooring slabs 14 have a plurality of regularly spaced mechanical keys 60 on their upper surface and further mechanical keys 62 located along their ends 64. The purpose of the floor mechanical keys 60 is to provide a mechanical bond between the concrete pour 16 and the flooring slabs 14 which will remain even in the event that the surface bond between the concrete pour 16 and the flooring slabs 14 is lost. The mechanical keys 60 thus provide resistance to lateral and dynamic loads. The purpose of the end mechanical keys 62 is to locate between the beam mechanical keys 40 to provide further resistance to lateral and dynamic loads. The end mechanical keys 62 also provide an increase in the area of contact with the 8 concrete pour 16. The mechanical keys 40, 60 and 62 provide reliable connection and co-operation between the flooring slabs 14, the beams 12 and the concrete pour 16.

The flooring slabs 14 also typically have ribs 66 as shown in Figures 5 and 8. The ribs 66 increase the load carrying capability of the flooring slabs 14 whilst allowing the mass of the flooring slabs 14 to keep to the minimum required to support construction loadings without failure of the flooring slabs 14.

The result of the co-operation beams 12 and the flooring slabs 14 is that there is a formwork upon which the concrete can be poured. Once the concrete is poured and set the effect of the co-operation of the beams 12, the flooring slabs 14 and the concrete pour 16 is that of a plurality of T-beams 70 connected at their flanges 72 and with their webs 74 supported upon the wall 18. The result of the setting of the concrete pour 16 is that the beams 12, the flooring slabs 14 and the concrete pour 16 become a single monolithic structure.

Optionally, distribution ribs 80 can be fixed between adjacent beams 12. The 0I, 1 distribution ribs 80 are typically disposed intermediate the length of the beams 12 and ages 6:90o perpendicular to the beams 12. The purpose of the distribution ribs 80 is to spread the 0000 S.g.

°load which is experienced by one beam 12 to it two adjacent beams 12. This has the effect of reducing the displacement of the floor produced by a concentrated load to 0S*0 0o S the adjacent beams 12 so as to average out the deflection of the floor. That is, the 20 distribution ribs 80 serve to reduce the effect known as "key but forming". o• Typically, mesh is placed on top of the flooring slabs 14 prior to pouring the concrete so as to prevent shrinkage cracks.

If extra reinforcing is required due to increased loading, reinforcing bars may be placed in the cavities 22 of the beams 12.

In use, a suspended floor can be made by the flooring system 10 of the present invention in accordance with the following method.

The beam halves 20 and the flooring slabs 14 can easily be cast on site. This avoids the problem of damage which plagues prior art pre-fabricated concrete components.

beam halves 20 are lifted up and set on top of the wall 18 with the ends of the beam halves 20 being supported by opposite walls 18. The beam halves 20 are arranged in pairs with the feet 32 and the flanges 36 of each beam half 20 being oriented towards each other and the feet 32 in contact with each other so at to form the cavity 22. Adjacent pairs of the beam halves 20 are disposed substantially parallel to each other at regular intervals. For example, the pairs of beam halves 20 could be located at 600mm centres.

The flooring slabs 14 are then lifted up and placed upon the beam halves 20. To do this the ends 64 of each of the flooring slabs 14 are positioned on the closer beam

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S halves 20 of each pair of beam halves 20 of two adjacent pairs of beam halves 20. The 0555 flooring slabs 14 are positioned such that the end mechanical keys 62 interlock with

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:i the beam mechanical keys 40 as shown in Figure 4. The flooring slabs 14 are placed over the entire extent of the beam halves 20 in this manner.

Reinforcing bars are next placed in the cavity 22 and reinforcing mesh is placed upon the flooring slabs 14.

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Removable formwork may be placed in the necessary positions to complete the

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S formwork for the concrete pour, such as around the perimeter of the floor structure.

Next concrete is poured, in a conventional manner, into the cavities 22 and upon the oa

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flooring slabs 14 up to the desired thickness of the floor, typically greater than 50 mm Sthickness.

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Once the concrete has cured the protrusions 40, 60 and 62 provide mechanical keying with the concrete. Also, the beam halves 20 and the flooring slabs 14 form a single monolithic structure. Any removable formwork used would be removed.

To provide geometric stability and added rigidity to the resultant floor a perimeteral beam 100 can be used as shown in Figures 6 and 7. The perimeteral beam 100 is set upon the wall 18 and extends in a continuous manner all around the top of the wall 18. The permeteral beam 100 comprises reinforcing bars 102 and ties 104. The perimeteral beam 100 is completed when the concrete pour 16 is cured. The perimeteral beam 100 has the effect of joining the ends of each of the beams 12 together and making the floor a matrix of connected beams 12 instead of a set of separate beams 12. The floor is then a very stiff diaphragm which is able to transfer lateral loads on one wall 18 to the two side walls 18 which are perpendicular to the loaded wall and are thus much more able to withstand the loading.

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SL The flooring system 10 of the present invention has the advantage that all of its S. components can be lifted manually thus obviating the need for a crane. Also, the flooring slabs 14 and the beam halves 20 become a single monolithic structure with the concrete pour 16 and hence the resultant floor is stronger than prior art floors made using hardiplank floor panels. Further, the mechanical keys 40, 60 and 62 provide a keying in vertical and horizontal directions to provide lateral and dynamic load capability for the flooring system 10. Hence, the flooring system 10 is suitable for seismic regions. Still further, the distribution ribs 80 have the advantage that concentrated loads can be spread to adjacent beams 12. Still further the flooring system 10 is relatively light (about 220 kg/m2), is simple to construct, is relatively 11 low in cost, can be made with relatively low strength concrete and requires less reinforcing steel.

The flooring system 10 is relatively light, very stiff and able to resist vertical, horizontal and dynamic loads and vibration.

The flooring system 10 has the advantages of a precast structure while not loosing the advantages of a monolithical structure. The flooring system 10 also provides a structure resistance to vibration and seismic loading.

Modifications and variation such as would be apparent to a skill addressee are considered within the scope of the present invention. For example, the shape of the cavity 22 could be other than that shown on the drawings provided that the gap 34 is narrower than the widest extent 38. Also, the flooring slabs 14 could be other than square when viewed in plan for example rectangular.

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The claims defining the present invention are as follows: I. A flooring system including: a plurality of support beams being arranged substantially parallel to each other S and suspended between footings or walls of a building, each support beam having a longitudinally extending cavity, each cavity being able to receive and hold concrete during a pour; and a plurality of flooring slabs, the flooring slabs being supported by and extending between adjacent support beams to provide permanent formwork in conjunction with the support beams, the flooring slabs having a plurality of mechanical keys on upper surfaces thereof which provide a mechanical bond with the concrete pour such that the flooring slabs form a monolithic structure with the support beams once the concrete has been poured over the flooring slabs and the support beams.

2. A flooring system according to claim 1, wherein the mechanical keys of the flooring slabs are in the form of protrusions or recesses.

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3. A flooring system in accordance with claim 1 or 2, wherein each support beam

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20 includes two beam halves, the beam halves being located longitudinally juxtaposed to form a cavity, the cavity being able to receive and hold concrete during a pour, the .concrete once cured completing the volume of the support beam and forming a monolithic structure with the two beam halves.

Claims

4. A flooring system in accordance with claim 3, wherein the beam halves are substantially L-shaped. A flooring system in accordance with claim 3 or 4, wherein the beam halves have a head and foot, the foot is intended to be located upon a footing or wall and the head is intended to be disposed uppermost with respect to the foot.
6. A flooring system in accordance with claim 5, wherein the head has a flange which is located along the length of the head and the foot extends laterally from the beam half further than the flange so that when the pair of beam halves are placed into longitudinal juxtaposition the two feet meet and a gap is formed between the two heads, the gap being narrower than the widest extent of the cavity.
7. A flooring system in accordance with any one of claims 3 to 6, wherein the support beams are made of concrete or like material. 9 0*
8. A flooring system in accordance with any one of claims 3 to 7 wherein the OSS@ 0000 flooring slabs are made of concrete of like material. 0000 c,
9. The flooring system according to any one of the preceding claims, wherein the flooring slabs are able to be lifted in place manually.
10. A flooring system in accordance with any one of the preceding claims, wherein reinforcing mesh is placed above the flooring slabs to prevent the surface of 14 the concrete pour from developing cracks due to shrinkage and to increase the strength of the floor once completed.
11. A flooring system in accordance with any one of the preceding claims, wherein the flooring system includes reinforcing rods located within the cavity of the support beams.
12. A flooring system in accordance with any one of claims 5 to 11, wherein each of the beams has a plurality of regularly spaced mechanical keys on top of the head.
13. A flooring system in accordance with claim 12, wherein the flooring slabs have a plurality of mechanical keys located along edges of the slabs located between the beam mechanical keys to provide resistance to lateral movement under load. 15 14. A flooring system in accordance with any one of the preceding claims, C@SO 80 Swherein the flooring slabs have downwardly extending ribs which rest upon the C.. support beams. ego A flooring system in accordance with any one of the preceding claims, wherein the flooring system includes distribution ribs fixed between adjacent beams 0" :04, disposed intermediate the length of the beams and perpendicular to the beams. to.. S° 16. A method of constructing a suspended floor, including the steps of preparing a support structure for the suspended floor, such as a footing or o: walls, locating a plurality of support beams between the footings or walls, the support beams being spaced from and substantially parallel to one another upon the support structure; each beam having a longitudinally extending cavity, each cavity being able to receive and hold concrete during a pour; supporting a plurality of flooring slabs between each adjacent support beam to form permanent formwork in conjunction with the support beams to receive the poured concrete, the flooring slabs having a plurality of mechanical keys on upper surfaces thereof which provide a mechanical bond between the concrete pour and the flooring slabs; and •10 pouring the concrete over the flooring slabs and the support beams, the .00 s ee.. concrete, once cured, forming a monolithic structure with the flooring slabs and the support beams. 000.
17. A method of constructing a suspended floor in accordance with claim 16, wherein pairs of beam halves are longitudinally juxtaposed to each other to form a plurality of support beams each having a cavity located between the respective pairs S• of beam halves for receiving poured concrete.
18. A method of constructing a suspended floor in accordance with either claim 20 16 or 17, wherein a perimeteral beam is set upon the support structure and extends in a continuous manner all around the support structure, and the perimeteral beam is completed when the concrete pour is cured.
19. A flooring system substantially as hereinbefore described with reference to the accompanying drawings. 'A 16 A method of constructing a suspended floor substantially as hereinbefore described with reference to the accompanying drawings. DATED THIS 9 THDAY OF FEBRUARY 1999. JACEK BLUM By his Patent Attorneys LORD AND COMPANY PERTH, WESTERN AUSTRALIA S S S. S S *0 *5*S 5.55 5555 SS S 9 9e .5 S S S. 5* *5 5 S S ABSTRACT A flooring system including a plurality of support beams suspended between footings or walls of a building and a plurality of flooring slabs. The flooring slabs are supported by and span between adjacent support beams to provide permanent formwork in conjunction with the support beams. The flooring slabs form a monolithic structure with the support beams once concrete has been poured over the flooring slabs and the support beams. The system is characterised by enhanced resistance against vibration and it is suitable for seismic areas. It is distinguished also by relatively low self-weight *0e0 S 0. *9 O S 9 *O S O r.e, S