BUILDING ELEMENT, SYSTEM AND METHOD

Abstract

A building element adapted to provide thermal insulation between two building parts such as a floor or ceiling slab and a balcony slab is described. The element comprises: an elongate insulating body; a plurality of reinforcing elements passing through and projecting on either side beyond the insulating body so as to be disposed in use within and serve to reinforce each of the two building parts; at least one through apertured formation extending transversely through the insulating body so as to be able to receive in use a post-tensioning tendon member. A building system including at least one such building element, a building structure incorporating such a building system and a method of building are also described.

Claims

1. A building element adapted to provide thermal insulation between two building parts comprising: an elongate insulating body; a plurality of reinforcing elements passing through and projecting on either side beyond the insulating body so as to be disposed in use within and serve to reinforce each of the two building parts; at least one through apertured formation extending transversely through the insulating body so as to be able to receive in use a post-tensioning tendon member.

2. The building element in accordance with claim 1 wherein the through apertured formation defines an aperture in the building element being complementarily sized and shaped with respect to a post-tensioning tendon member such that the post-tensioning tendon member is receivable within and passes through the through aperture in use.

3. The building element in accordance with claim 1 wherein the through apertured formation comprises a tubular member defining a through aperture.

4. The building element in accordance with claim 3 wherein the tubular member comprises a central tubular sheath passing through the thickness of the elongate insulating body and an adaptor portion provided at each end thereof so disposed as to project beyond the first insulating body on either side thereof.

5. The building element in accordance with claim 1, comprising at least one load transfer portion comprising a first insulating body with the said plurality of reinforcing elements passing through and projecting on either side beyond the first insulating body, and at least one transition portion continuously aligned with the load transfer portion and comprising a second insulating body with at least one of the said apertured formations formed in and extending transversely through the second insulating body.

6. The building element in accordance with claim 5 comprising a plurality of load transfer portions and a plurality of transition portions alternately and successively aligned.

7. The building element in accordance with claim 1, wherein the apertured formation defines an aperture of constant cross-section.

8. The building element in accordance with claim 7 wherein the apertured formation comprises a tubular member defining a through aperture, at least a central tubular sheath thereof passing through the thickness of the elongate insulating body being of constant cross-section.

9. The building element in accordance with claim 1, wherein the reinforcing elements passing through and projecting on either side beyond the insulating body comprise one or more of: tensile reinforcing elements; shear reinforcing elements; compressive reinforcing elements.

10. The building element in accordance with claim 1, wherein the reinforcing elements comprise steel rods or bars.

11. The building element in accordance with claim 1, wherein at least those portions of the reinforcing elements that project beyond the insulating body are adapted to engage within cast concrete.

12. A building system adapted to provide thermal insulation between two building parts is provided comprising: at least one building element including: an elongate insulating body; a plurality of reinforcing elements passing through and projecting on either side beyond the insulating body so as to be disposed in use within and serve to reinforce each of the two building parts; and at least one through apertured formation extending transversely through the insulating body so as to be able to receive in use a post-tensioning tendon member; at least one post-tensioning tendon; each through aperture in the building element being complementarily sized and shaped with respect to each post-tensioning tendon member so that the post-tensioning tendon member is receivable within and passes through the through aperture in use.

13. The building system in accordance with claim 12 wherein the through aperture is sized and shaped so as to receive the post-tensioning tendon member in relatively snug fit.

14. The building system in accordance with claim 12 wherein the post-tensioning tendon comprises plural elongate steel tendon strands surrounded by a protective sheath or individually sheathed plural elongate steel tendon strands.

15. The building system in accordance with claim 12 wherein the post-tensioning tendon member comprises a mechanically continuous elongate member configured to extend in use through the through aperture and provided with integral or separate anchor formations at each end configured to anchor the end of the post-tensioning tendon member to a building part during use.

16. A building structure comprising: a building system comprising: a building element having an elongate insulating body, a plurality of reinforcing elements passing through and projecting on either side beyond the insulating body, and at least one through apertured formation extending transversely through the insulating body, and a post-tensioning tendon member; at least one post-tensioning tendon; each through aperture in the building element being complementarily sized and shaped with respect to each post-tensioning tendon member so that the post-tensioning tendon member is receivable within and passes through the through aperture in use; a first building part engaged with the reinforcing elements on a first side of the building element; a second building part engaged with the reinforcing elements on a second side of the building element; wherein the post-tensioning tendon member is received within and passes through the through aperture and is tensioned to apply a post-tensioning load to the building structure.

17. The building structure in accordance with claim 16 wherein the post-tensioning tendon member comprises anchor formations at each end anchored to each of the building parts.

18. The building structure in accordance with claim 16 wherein each building part is a cast concrete slab.

19. The building structure in accordance with claim 16 wherein the first building part is a floor or ceiling slab and the second building part is a balcony slab and the post-tensioning tendon is tensioned to apply a post-tensioning load between the ceiling slab and the balcony slab.

20. A method of building comprising the steps of: deploying a building element comprising an elongate insulating body and a plurality of reinforcing elements passing through and projecting on either side beyond the insulating body between two building parts such that the reinforcing elements are disposed within and serve to reinforce each of the two building parts; providing at least one through apertured formation extending transversely through the insulating body suitable to receive a post-tensioning tendon member.

21. The method of building in accordance with claim 20 wherein the through apertured formation defines an aperture in the building element being complementarily sized and shaped with respect to a post-tensioning tendon member with which it is to be used such that the post-tensioning tendon member is receivable within and passes through the through aperture in use.

22. The method of building in accordance with claim 20 further comprising the steps of: deploying a post-tensioning tendon member within and passing through the through aperture; tensioning the post-tensioning tendon member to apply a post-tensioning load between the two building parts.

23. The method of building in accordance with claim 20 wherein one of the building parts is a floor or ceiling slab and the other of the building parts is a balcony slab and the post-tensioning tendon is tensioned to apply a post-tensioning load between the floor or ceiling slab and the balcony slab.

24. The method of building in accordance with claim 23 wherein the post-tensioning tendon member comprises anchor formations at each end and the method comprises anchoring an anchor formation to each of the building parts.

25. The method of building in accordance with claim 24 wherein the anchor formations comprise a passive or dead-end and active or live-end anchor pair.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0058] The invention will now be described by way of example only with reference to FIGS. 1 to 6 of the accompanying drawings, in which:

[0059] FIGS. 1 to 3 illustrate an example of a prior art thermally insulated balcony connection system:

[0060] FIGS. 4 to 6 illustrate balcony connection systems comprising embodiments of the invention.

DETAILED DESCRIPTION

[0061] FIGS. 1 to 3 illustrate an example prior art thermally insulated balcony connection system for effecting a connection between two building slabs so as to include a thermal break between the two slabs but to provide for continuous reinforcement through the thermal break.

[0062] The illustrated example of the prior art is a high performance thermal break system for concrete-to-concrete applications, and in particular for the joining of a floor slab within the building envelope to a balcony slab projecting outside. A modular principle of construction is typically applied, with multiple modular building elements incorporating the thermal break and necessary reinforcement structures being used to form a complete structure. The principle is illustrated in FIGS. 1 to 3.

[0063] In FIG. 1, a building element module incorporating a thermal break and reinforcement structures is shown in perspective view. FIG. 2 shows a vertical cross-section of the modular building element illustrated in FIG. 1. In each case, the building element is shown as it would be supplied, and in particular therefore not including the concrete slabs in place.

[0064] The building element consists of an elongate insulating body which extends to provide the thermal break in use, and which in the embodiment comprises fire-resistant mineral wool (5) shaped and protected by a plastic U-shaped profile element (7) at the top and bottom. Other materials, for example including insulating foams, may be used in alternative installations.

[0065] The building element includes various reinforcing elements which pass through and project on either side beyond the insulating body and in use, as illustrated in FIG. 3, engage within the two concrete slabs. These comprise tensile (9) and shear (11) bars and compression studs (13).

[0066] In the illustrated embodiment, the tensile and shear reinforcement bars (9, 11) consist of 1.4301 stainless steel with the characteristics of BS500S. The tensile bars are continuous with no structural welding or point of weakness. The compression studs (13) are manufactured from 12 mm diameter high resistance 1.4301 stainless steel bars with hot-forged heads.

[0067] In addition to thermal and durability benefits, stainless steel reinforcement reduces concrete cover requirements and can therefore provide additional design efficiencies over carbon steel systems. However, material selection in this embodiment is illustrative only, and the skilled person would readily be able to choose other suitable reinforcement materials, for example including carbon steel systems, other metal systems and composite systems as applicable.

[0068] A building element module such as is illustrated in FIGS. 1 and 2 is shown in situ in use in FIG. 3 as a thermal break connection between first and second building slabs (21, 23) which may in the preferred application of the prior art system be a floor slab and a balcony slab.

[0069] In the illustrated example the slabs comprise conventional concrete slabs cast in situ, and are shown with the building element (3) in position to act as a thermal break between them. The rebar through reinforcements (9, 11) cooperate with the additional structural framework elements (25) within the two concrete slabs to provide structure within the concrete and in particular to provide a mechanism to transfer bending moment and shear forces across the thermal break whilst minimising compromise of the thermal insulation provided by the inherently fire-resistant mineral wool. The continuous stainless steel reinforcement through the building element maximises strength, thermal efficiency and corrosion protection whilst the compression studs reduce rebar reinforcement congestion and simplify installation.

[0070] A primary limitation with the prior art system that the invention seeks to address is the difficulty it presents if it desired to build in post-construction tensioning to apply a post-tensioning load between the floor slab and the balcony slab. The system does not allow for post-tensioning tendons to run across the line of the thermal break in a manner which would allow stressing to be applied to a live-end anchor at the far balcony edge. The key to the invention, as discussed with reference to the embodiment below, is develop a modification to modular systems of which FIGS. 1 to 3 are illustrative that enables post-tensioning tendons to run straight through the thermal break and thereby to enable live-end anchors to be positioned at the edges of balconies.

[0071] Accordingly, although FIGS. 1 to 3 above are presented as illustrative of a prior art modular connection system, and discussion of features, materials and construction principles is made in that context, it will be understood that the key to the invention is the way in which such systems are modified to allow for the provision of post-tensioning tendons. It is likely that other aspects of conventional modular systems such as are illustrated in FIGS. 1 to 3 will be applicable to, and even desirable in, embodiments of the invention and accordingly those other features, materials and construction principles described with reference to FIGS. 1 to 3 may also be seen as applicable to embodiments of the invention where appropriate.

[0072] Embodiments of the invention, illustrated in FIGS. 4 to 6, attempt to develop the principles of a modular system such as might be embodied in the example in FIGS. 1 to 3 to enable post-tensioning tendons to be run through the thermal break to allow live-end or dead-end anchors to be positioned at the edge of balconies and apply a post-tensioning load with the attendant advantages to the resultant built structure that will then accrue.

[0073] The invention achieves this additional functionality by providing at least one through aperture formation extending transversely through the insulating body so as to provide a means to receive a post-tensioning tendon member and apply a post-tensioning load. This post-tensioning tendon member is supplementary to the rebar.

[0074] In the illustrated embodiment this is effected in that the insulating body consists of successively arranged load carrying load transfer portions or transfer units and apertured transition portions for receiving the post-tensioning tendons. This is an effective configuration in many circumstances, although it is presented as an illustrative embodiment only, and the skilled person will appreciate that in alternative embodiment the apertures for the post-tensioning tendons may be fully integrated with the reinforcing element.

[0075] In the illustrated embodiment the load transfer portions or transfer units comprise primary load transfer units of generally conventional design in that they embody the principles of the prior art to carry the combination of bending moment, shear and compression across the thermal break, in particular including through reinforcements that pass through the insulating body. The transition portions comprise short transition elements or portions disposed between the primary load transfer units that define apertured portions through which the tendons may be passed. These apertured portions are additional to any holes inherent in the body where the primary through reinforcements pass through, and are open in the as-reinforced state, and for example define an open aperture that is complementarily sized and shaped with respect to a post-tensioning tendon member with which it is to be used, such that the post-tensioning tendon member is receivable within and passes through the through aperture in use.

[0076] This concept is illustrated in a first example embodiment shown in partially cutaway perspective view in FIG. 4 and in a second example embodiment in schematic plan view and vertical section in FIG. 5 and a third example embodiment in schematic plan view and vertical section in FIG. 6.

[0077] The illustrated embodiments of the invention have a number of general features in common, and these are where applicable referenced by the same reference numeral. Where a variant feature is shown in a given embodiment, it will be appreciated that this is by way of example only and that except where this feature is necessarily technically linked to other features of the embodiment, such a variant would be interchangeably applicable to each embodiment.

[0078] In the illustrated embodiments of the invention, an insulating body (53) comprises a plurality of load transfer elements (55) which may be discrete load transfer units or suitable portions of an integral insulating body and a plurality of transition elements (57) which may be discrete transition units or suitable portions of an integral insulating body which are alternately and successively aligned to make up the insulating body (53). For illustrative purposes, a portion of an embodiment of the invention including multiple such alternating load transfer elements (55) and transition elements (57) is shown in FIG. 4. FIGS. 5 and 6 show a portion of an embodiment of the invention including two load transfer elements (55) with a transition element (57) between.

[0079] The load transfer elements (55) are configured to transfer load across the thermal break in familiar manner, and in the illustrated embodiments include tensile elements (59), and elements to transfer shear and compression, which by way of illustrative example include the compression studs (63) of FIG. 4 and the arrangement of elongate members (59, 61) to transfer compression and shear shown in the inset of FIGS. 5 and 6.

[0080] The load transfer elements may embody any known materials and principles of construction including those which might be embodied in similar prior art modular thermal break systems such as illustrated in FIGS. 1 to 3. In particular, in the preferred embodiment illustrated in FIGS. 4 to 6 the thermal insulation may for example comprise fire-resistant mineral wool, and the tension, compression and shear reinforcement may comprise suitable steel, and for example stainless steel, for example being 1.4301 stainless steel with the characteristics of BS500S. Other materials may be selected as applicable for other applications.

[0081] The invention is characterised by the provision of transition elements (57) which define apertured portions that allow post tensioning tendons (65) to pass through the thermal break.

[0082] FIG. 4 illustrates the system in situ joining a floor slab (71) and a balcony slab (73). The outermost edge of the balcony slab (73) carries a live-end anchor (67) by means of which a post-tensioning load can be applied using the tendon (65). The live-end anchor can be employed without interference to the thermal break system, which need not be broken at anchor locations. The load transfer principles of conventional modular thermal break systems need not be compromised, and can be otherwise employed, for example by provision of alternating conventional load transfer units and transition units in the manner of the illustrated embodiment.

[0083] FIG. 5 illustrates the system with a live-end anchor (67) at either end by means of which a post-tensioning load can be applied using the tendon. In many practical applications, it will be more appropriate to have a dead end anchor at one end, as is illustrated by FIG. 6, in which a tendon extends between a live-end anchor (67) at a first end and a dead end anchor (75) at the other. The anchor formations thus comprise a passive and active anchor pair. In a typical construction to which the invention could be applied, where one of the building parts is a floor or ceiling slab and the other of the building parts is a balcony slab, the live end anchor may be suitably anchored with respect to the balcony slab to enable a post-tensioning load to be applied.

[0084] The principles behind active or live-end and passive or dead-end anchors are well established and the skilled person will understand that any example shown here is illustrative only. In particular, the skilled person will appreciate that the invention could readily be applied to the range of single and multiple bonded and unbonded anchorage structures that might generally be known for post-tensioning systems.

[0085] The load transfer elements may for example be 300 mm long and embody similar design principles to existing thermal breaks with load transfer formations such as those illustrated with reference to FIGS. 1 to 3, although the amount of compression generated by the post-tensioning tendons of an embodiment of the invention in use is likely to require modification to the number and position of the compression studs.

[0086] The transition elements between load transfer elements may be typically 150 mm long and fitted with a transition tube to define and line a single aperture therein. This arrangement is most clearly shown in the inset in FIGS. 5 and 6. A transition tube is shown consisting of a central sleeve (81) and adaptor portions (83) which in the embodiment are fabricated from a suitable plastics material but may alternatively be metallic for example for combustion resistance. A central sleeve (81) defines the aperture, and provides a duct for the post-tensioning tendons strands to pass. In the example it has an oval cross-section, but circular or other cross-sections may be appropriate.

[0087] The post-tensioning tendon may be of any suitable conventional design, for example including multiple steel strands, and is for example a three or five strand system. It may be made modular to allow for adjustment of design centre. It may be bonded or unbonded. When a bonded post-tensioning system configuration is used, standard galvanised ducting or plastic ducting as is routinely supplied with post-tensioning tendon systems will be inserted at each extremity and fitted with heat-shrink sleeves or other suitable means to form a continuous tendon. When an unbonded post-tensioning system configuration with individual plastic-coated strands is used, the strands may be simply inserted through the transition tube without further precautions.

[0088] In a typical concept for assembly on site, multiple building elements such as are illustrated in FIGS. 4 to 6 would be delivered along with multiple post-tensioning tendons, and these building elements would be placed end to end to form a continuous thermal break through which the post-tensioning elements could be inserted to apply a post-tensioning load to the balcony parts.

[0089] This system thus combines the structural and thermal features of known thermal break systems with the ability to apply the post-tensioning load in the manner described. Advantages include: speed of installation as the tendons will run straight through the thermal break; allowing concrete to be cast in the usual manner simultaneously for floor and balcony; absence of interference between live-end anchors and balcony connectors.