AU2009203103A1

AU2009203103A1 - Suspended flooring system

Info

Publication number: AU2009203103A1
Application number: AU2009203103A
Authority: AU
Inventors: Michael Anthony Dunne
Original assignee: ULTRAFLOOR Pty Ltd
Current assignee: ULTRAFLOOR Pty Ltd
Priority date: 2008-07-31
Filing date: 2009-07-30
Publication date: 2010-02-18

Description

S&F Ref: 916240 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address UltraFloor Pty. Ltd., of Applicant: an Australian Company ACN 003 892 957, of 6 Kyle Street, Rutherford, New South Wales, 2320, Australia Actual Inventor(s): Michael Anthony Dunne Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Suspended flooring system Associated Provisional Application Details: [33] Country: [31] Appl'n No(s): [32] Application Date: AU 2008903931 31 Jul 2008 The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(2226701_1) I SUSPENDED FLOORING SYSTEM Field of the Invention The present invention relates to the field of construction and more specifically 5 relates to a suspended flooring system and associated method of forming a suspended floor. Background of the Invention Suspended concrete floors, as are typically utilised in multi-storey buildings such 10 as car parks, office blocks and residential apartments, are formed by any of various methods. To enable suspended concrete floors to span across any significant distance, a series of parallel reinforced beams is sometimes provided, each spanning between, and supported on, support members that extend perpendicular to the reinforcing beams. Such support members might be walls or band beams that are themselves supported by is columns. The reinforcing beams are reinforced by structural steel strands, which may be either pre or post-stressed, to carry tension loads in the floor. The reinforcing beams typically project below the lowest surface of the conventional floor slab and may be integrally formed with the remainder of the floor or may be pre-cast elements located in situ prior to forming the rest of the floor structure above the reinforcing beams. 20 Provision of the underhanging reinforcing beams typically increases the total thickness of a conventional floor and also provides what is often an undesirable aesthetic finish in applications where no false ceiling is provided below the suspended floor. Object of the Invention 25 It is the object of the present invention to substantially overcome or at least ameliorate one or more of the above disadvantages. Summary of the Invention In a first aspect, the present invention provides a suspended flooring system 30 comprising: an array of generally parallel pre-cast reinforced concrete beams, each of said reinforced concrete beams having a lower face lying in a common horizontal plane, opposing ends of each said reinforced concrete beam being supported by elongate support members that each extend generally perpendicular to said reinforced concrete beams, 2 each said reinforced concrete beam including one or more pre-stressed steel strands extending along its length; a concrete floor element poured in situ so as to extend over and between said reinforced concrete beams between said support members such that said reinforced s concrete beams are located within a thickness of said concrete floor element. Typically, the lower face of said concrete floor element lies substantially in said horizontal plane. Typically, said concrete floor element further comprises steel reinforcing located above said reinforced concrete beams. 10 Typically, said steel reinforcing comprises steel reinforcing mesh. In one form, at least one of said support members comprises a wall. In another form, at least one of said support members comprises a concrete band beam. In one embodiment, each said band beam may comprise one or more pre-cast 15 reinforced concrete shell beams. The concrete floor element may extend over said shell beam(s). Typically, each said band beam is supported by a plurality of columns spaced along the length of said band beam. In another form, at least one of said support members comprises a steel beam. 20 Typically, each said steel beam is supported by a plurality of columns spaced along the length of said steel beam. The flooring system may further comprise permanent formwork, said reinforced concrete beams being located on said permanent formwork. Typically, said permanent formwork comprises steel structural formwork. 25 In another aspect, the present invention provides a method of forming a suspended floor comprising the steps of; providing a plurality of elongate support members in a generally parallel arrangement; arranging formwork between said support members, said formwork having an upper 30 surface in a horizontal plane; arranging an array of parallel pre-cast reinforced concrete beams on said formwork such that said reinforced concrete beams each extend generally perpendicular to said support members with opposing ends of each said reinforced concrete beam supported by said support members, each said reinforced concrete beam including one or 35 more pre-stressed steel strands extending along its length; and 3 pouring concrete in situ onto said formwork and over and between each of said reinforced concrete beams so as to form a concrete floor element with each of said reinforced concrete beams located within a thickness of said concrete floor element. In one form, at least one of said support members comprises a wall or steel beam. 5 In an alternate form, at least one of said elongate support members comprises a concrete band beam. In one embodiment, said method includes the step of forming said band beams in situ. In another embodiment, said band beam includes one or more pre-cast reinforced concrete io shell beams. Typically, said concrete is poured so as to extend over said shell beam(s). Brief Description of the Drawings Preferred embodiments of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: is Figure 1 is a plan view of a suspended flooring system according to a first embodiment; Figure 2 is a cross-sectional view of the flooring system of Figure 1 taken at section 2-2; Figure 3 is a cross-sectional view of the suspended flooring system of Figure 1 20 taken at section 3-3; Figure 4 is a cross-sectional view of a modified form of the flooring system of Figure 1, equivalent to the cross-section of Figure 3; Figure 5 is a plan view of a suspended flooring system according to a second embodiment; 25 Figure 6 is a cross-sectional view of the flooring system of Figure 5 taken through section 6-6; Figure 7 is a plan view of a suspended flooring system according to a third embodiment; Figure 8 is a cross-sectional view of the flooring system of Figure 7, taken 30 through section 8-8; Figure 9 is a plan view of a suspended flooring system according to a fourth embodiment; and Figure 10 is a cross-sectional view of the flooring system of Figure 9 taken through Section 10-10. 35 4 Detailed Description of the Preferred Embodiments Referring to Figures I to 3 of the accompanying drawings, a suspended flooring system 100 according to a first embodiment includes an array of parallel pre-cast reinforced concrete beams 101. The lower face 102 of each reinforced concrete beam 101 5 lies in a common horizontal plane P. Each reinforced concrete beam 101 spans between a pair of elongate support members 105, with opposing ends 103, 104 of each reinforced concrete beam 101 being supported by the support members 105. A separate array of reinforced concrete beams 10 1 will typically be arranged in each bay defined between each successive pair of support members 105. 10 In the first embodiment, the support members 105 are in the form of structural walls 105 that each extend generally perpendicular to the reinforced concrete beams. The walls 105 will typically be walls between rooms in the building level directly beneath the flooring system 100. Each reinforced concrete beam 101 includes one or more pre-stressed steel is strands 106 extending along its length. Each of the reinforced concrete beams 101 may be of the type known as the Ultrafloor@ beam, available from the present applicant. The reinforced concrete beams 101 will typically have a rectangular cross-section, however, various other cross-sections are envisaged. The flooring system 100 further comprises a concrete floor element 107 that is 20 poured in situ so as to extend over and between the reinforced concrete beams 101 between the walls 105. Where several bays are defined by successive pairs of walls 105, a single concrete floor element 107 will typically be poured so as to extend over intermediate walls, with expansion joints as dictated by the engineering design. The reinforced concrete beams 101 are located within the thickness of the concrete floor 25 element 107 and bond with the side walls 108 and upper face 109 of each reinforced concrete beam 101, forming a composite floor slab. The lower face 111 of the concrete floor element 107 will typically lie in the horizontal plane P, so as to be flush with the lower face 102 of each reinforced concrete beam 101. It is envisaged, however, that the lower face Ill of the concrete floor element 107 might protrude slightly below the lower 30 face 102 of the reinforced concrete beams 101 if so desired. Steel reinforcing, such as steel reinforcing mesh 112 and/or loose reinforcement bars 113 may be embedded within the concrete floor element 107 above or beside the reinforced concrete beams 101 as dictated by the engineering design. Void formers 114 may also be located within the thickness in the concrete floor element 107, between one 35 or more pairs of reinforced concrete beams 101. The void formers 114 define elongate 5 voids 115 for location of services within the concrete floor element 107 and reduce the overall weight and concrete usage of the flooring system 100. The flooring system 100 of the first embodiment further comprises permanent formwork 116, on which the reinforced concrete beams 101 are located. The permanent 5 formwork 116 may comprise steel structural formwork, such as Bondek@ formwork. The permanent formwork serves both as formwork and structural reinforcement, removing the need for traditional steel reinforcing in the lower portion of the concrete floor element 107. The specific configuration of the flooring system 100 may vary, depending upon io physical constraints and engineering design. In the specific configuration of the first embodiment depicted, the reinforced concrete beams 101 will typically be spaced up to 1500mm between beam centre lines, the walls 105 will typically be spaced up to 8400mm between centre lines, and the thickness of the concrete floor element 107 will typically be of the order of 180mm. Each concrete reinforcing beam 101 here has a width of 100mm is and thickness of 100mm and two 9.3mm seven strand structural steel reinforcing strands 106. To form the suspended floor system 100, the walls 105 are first provided, extending in a generally parallel arrangement. The formwork 116 is then arranged between the walls 105. With the formwork 116 being permanent formwork, the 20 formwork 116 will also be supported on the walls 105, extending across intermediate walls between adjacent bays. Additional removable supports may be located between the walls 105 to temporarily support the formwork 116 as required. The formwork 116 is arranged such that an upper surface thereof is arranged in the horizontal plane P. The array of reinforced concrete beams 101 is then arranged on the formwork 116, extending 25 in a generally parallel arrangement perpendicular to the walls 105. Opposing ends 103, 104 of each reinforced concrete beam 101 are located so as to be supported by the walls 105. Steel reinforcing, including reinforcing mesh 112 and loose bars 113, is then arranged above the reinforced concrete beams 101 as dictated by the engineering design. Concrete is then poured in situ onto the formwork 116 and over and between each of the 30 reinforced concrete beams 101 so as to form the concrete floor element 107 with each of the reinforced concrete beams 101 located within the thickness of the concrete floor element 107. Once the concrete floor element 107 has cured sufficiently, any removable supports may be removed from beneath the formwork 116. The suspended floor system 35 100 is then complete. The reinforced concrete beams 101 do not project beneath the 6 lower surface of the concrete floor element 107, thereby potentially reducing the overall thickness of the floor, and providing a neater finish, particularly for applications where the lower face of the floor remains exposed. There is also, typically, no need for post tensioning or pre-stressing of reinforcing on site through use of the pre-cast reinforced s concrete beams 101. Rather than utilising permanent formwork 116 as discussed above, traditional temporary formwork may be utilised, providing a modified form of the suspended floor 100' as depicted in Figure 4, in which the permanent formwork is limited, leaving the lower face 111 of the concrete floor element 107 and the lower face 102 of the reinforced to concrete beams 101 exposed. Additional floor reinforcing will typically be located within the thickness of the concrete floor element 107 between the reinforced concrete beams 101. When forming the modified suspended floor 100' of Figure 4, the temporary formwork is arranged between the walls 105, supported by removable supports until the concrete floor element 107 is fully cured, following the removable supports and Is temporary formwork is removed. Referring to Figures 5 and 6, a suspended flooring system 200 according to a second embodiment utilises elongate structural members 205, typically in the form of steel I-beams 205, in place of the structural walls 105 of the first embodiment discussed above. The opposing ends 103, 104 of the reinforced concrete beams 101 are supported 20 on the upper flange 206 of each of the I-beams 205 or on welded seat angles 208 on one or either side of the I-beam 205. The steel I-beams 205 are supported by any of various forms of support, with such support here being provided by steel columns 207 spaced along the length of each steel I-beam 205. The columns 207 and I-beams 205 are arranged in place prior to location of the formwork (which may either be permanent 25 formwork 116 as discussed above, or temporary formwork) and the reinforced concrete beams 101. The concrete floor element 107 is then poured in situ in the same manner as discussed above in relation to the first embodiment. A suspended flooring system 300 according to a third embodiment is depicted in Figures 7 and 8. In this embodiment, the reinforced concrete beams 101 are supported by 30 elongate support members 305 in the form of band beams 305. The band beams 305 may be formed in situ prior to placement of the reinforced concrete beams 101 and subsequent pouring of the concrete floor element 107. Alternatively, in the specific arrangement depicted in Figures 7 and 8, the band beams 305 are integrally formed in situ with the concrete floor element 107. Additional removable formwork is arranged for formation of 35 the band beams 305, supported by removable supports and configured such that 7 permanent supports, such as concrete columns 307, will support the finished band beam 305. The opposing ends 103, 104 of the reinforced concrete beams 101 are arranged so as to project into the void defined by the removable formwork in which the band beam 305 is to be formed. As a result, as best depicted in Figure 8, the reinforced concrete beams 5 101 will be supported by the band beam 305 in the completed flooring system 300. The opposing ends 103, 104 of the reinforced concrete beams 101 will typically project about 100mm or so into the band beams 305. Additional steel reinforcing (not depicted) will typically be provided in the band beams 305, and the steel reinforcing mesh 112 and loose reinforcement bars 113 of the concrete floor element 107 will also extend across the io upper region of each band beam 305. The band beam 305 and concrete floor element 107 will typically be formed with a single in situ concrete pour. As for the first embodiment, either permanent formwork or removable formwork may be utilised when forming the concrete floor element 107. Whilst the particular configuration of band beams 305 will vary, in the arrangement depicted the band beams 305 have a thickness of 330mm and is width of 2400mm. In a fourth and preferred embodiment, depicted in Figures 9 and 10, a suspended flooring system 400 utilises elongate support members 405, each comprising a composite band beam 405 formed of one or more pre-cast reinforced concrete shell beams 406 and in situ poured concrete that is poured with the concrete flooring element 107. In the 20 arrangement depicted, four reinforced concrete shell beams 406 are located side by side to form the lower portion of each band beam. The shell beams 406 are pre-cast with several pre-stressed reinforcing bars 407 extending through their length. The shell beams 406 may be in the form of Ultrashell beams, available from the present applicant, having a generally channel shape cross-section. 25 The shell beams 406 are first arranged in place supported by supports such as concrete columns 307 spaced along their length. Once the shell beams 406 are in place, the reinforced concrete beams 101 are arranged so that their opposing ends 103, 104 are supported by the upstanding flanges 408 of the outermost shell beams 406. Concrete is then poured in situ so as to form the concrete flooring element 107 with the concrete 30 extending across the shell beams 406 so as to therefore form the composite band beams of the concrete flooring system 400. The person skilled in the art will appreciate various other possible configurations of the suspended flooring system described.

Claims

1. A suspended flooring system comprising: an array of generally parallel pre-cast reinforced concrete beams, each of said reinforced concrete beams having a lower face lying in a common horizontal plane, s opposing ends of each said reinforced concrete beam being supported by elongate support members that each extend generally perpendicular to said reinforced concrete beams, each said reinforced concrete beam including one or more pre-stressed reinforcing bars extending along its length; a concrete floor element poured in situ so as to extend over and between said 1o reinforced concrete beams between said support members such that said reinforced concrete beams are located within a thickness of said concrete floor element.

2. The system of claim 1, wherein a lower face of said concrete floor element lies substantially in said horizontal plane. 15

3. The system of either of claims I and 2, wherein said concrete floor element further comprises steel reinforcing located above said reinforced concrete beams.

4. The system of claim 3, wherein said steel reinforcing comprises steel 20 reinforcing mesh.

5. The system of any one of claims I to 4, wherein at least one of said support members comprises a wall. 25

6. The system of any one of claims 1 to 4, wherein at least one of said support members comprises a concrete band beam.

7. The system of claim 6, wherein each said band beam comprises one or more pre-cast reinforced concrete shell beams. 30

8. The system of claim 7, wherein said concrete floor element extends over said shell beam(s).

9. The system of any one of claims 6 to 8, wherein each said band beam is 35 supported by a plurality of columns spaced along the length of said band beam. 9

10. The system of any one of claims 1 to 4, wherein at least one of said support members comprises a steel beam. 5

11. The system of claim 10, wherein each said steel beam is supported by a plurality of columns spaced along the length of said steel beam.

12. The system of any one of claims I to 11, further comprising permanent formwork, said reinforced concrete beams being located on said permanent formwork. 10

13. The system of claim 12, wherein said permanent formwork comprises steel structural formwork.

14. A method of forming a suspended floor comprising the steps of; 15 providing a plurality of elongate support members in a generally parallel arrangement; arranging formwork between said support members, said formwork having an upper surface in a horizontal plane; arranging an array of parallel pre-cast reinforced concrete beams on said 20 formwork such that said reinforced concrete beams each extend generally perpendicular to said support members with opposing ends of each said reinforced concrete beam supported by said support members, each said reinforced concrete beam including one or more pre-stressed steel strands extending along its length; and pouring concrete in situ onto said formwork and over and between each of said 25 reinforced concrete beams so as to form a concrete floor element with each of said reinforced concrete beams located within a thickness of said concrete floor element.

15. The method of claim 14, wherein at least one of said elongate support members comprises a wall. 30

16. The method of claim 14, wherein at least one of said elongate support members comprises a steel beam.

17. The method of claim 14, wherein at least one of said elongate support 35 members comprises a concrete band beam. 10

18. The method of claim 17, wherein said method includes the step of forming said band beam in situ. 5

19. The method of claim 17, wherein said band beam includes one or more pre-cast reinforced concrete shell beams.

20. The method of claim 19, wherein said concrete is poured so as to extend over said shell beam(s). 10 Dated 30 July, 2009 UltraFloor Pty. Ltd. Patent Attorneys for the Applicant/Nominated Person SPRUSON & FERGUSON