Building Element and a Building Structure Comprising the Building Element
The invention relates to a building element for a building structure such as a floor structure, comprising a member (10, 21, 40), said member having a planar portion (10d, 40d), and at least a part (11, 12, 43, 44, 45) of a mould (111) provided at an edge (10a, 21a, 40a) of the member (10, 21, 40).
The present invention relates to a building element for a building structure such as a floor structure according to the preamble of claim 1.
BACKGROUND OF THE INVENTIONIn known building construction procedures, e.g. concerning multi-storey buildings, floor structures are usually made in situ and are cast into homogenous reinforced concrete structures, having acceptable sound dampening and fire safety characteristics. However, this traditional construction method demands a relatively large amount of man-hours at the construction site, which increases the construction time and/or the number of workers needed.
A number of methods exist that increase the degree of prefabrication. Complete pre-fabrication of floor structures is not feasible, since problems with heavy transportation and meeting tolerance requirements, in turn requiring additional casting in situ, create obstacles. Many prefabrication methods include manufacturing a lower ceiling of the floor structure in concrete, which, with or without supports, forms a mould for upper casting with reinforcements. However, problems with heavy transportation remain in such methods as well. Overall, the economic gain is too small for known prefabrication solutions to become an attractive alternative to traditional floor structure construction.
With increasing requirements on the sound characteristics of buildings, traditional methods require the use of more concrete or separate upper layers, which in turn makes the construction process more expensive. Additionally, large amounts of concrete create the need for special considerations concerning humidity and longer periods for the concrete to dry, which extends the time needed for the construction. Also, the large amount of concrete in traditional floor structures requires stronger building foundation structures, which increases construction costs, and is also reason why some earth quakes create so much material damage, human injuries and loss of life.
Additional known solutions include the use beams made of thin sheet. WO00/34599 describes a pre-made concrete upper floor of a floor structure supported by I-beams made of thin steel sheet. There are similar solutions with C- and Z-beam sections. However, over large spans the concrete floor often becomes too heavy to be supported by the steel sheet beams. Also, fire safety considerations require complicated measures, such as providing lining on the steel sheet beams. Finally, as with other prefabrication solutions additional casting in situ is required due to problems with meeting tolerance requirements.
GB 572522 discloses a preformed beam made of concrete and having its side portions shaped to constitute side faces. A portion of the reinforcement projects through said side faces from the tension flange or web of the beam so as to constitute a shear reinforcement, external to the beam in a manner such that, when two adjacent beams abut side-by-side and a grouting material is placed in the groove formed by their side faces, the grouting will flow around the projecting shear reinforcements.
A disadvantage with the beam according to GB 572522 is that it is heavy, and that it during hardening tends to creep and shrink, i.e. the concrete is anisotropic, which causes actual deviations. When mounted on the site the dead weight causes irregular deflection, increasing the actual deviations. In order to achieve a flat ceiling a separate ceiling is required. The casting process in the grooves create an uneven floor surface, and thus there is a need to fill the floor surface with a self-levelling layer of concrete in order to be suitable for carpets and flooring material. Such self-levelling layers of concrete contain a substantial amount of water. The thickness of such a layer needs to be sufficient in order to be reliable, i.e. at least 10 mm thickness, i.e. a substantial amount of additional special concrete or the like is needed. Due to the high amount of water damp problems occur, and it takes a long time to dry this additional layer. In addition the junctions need to be sealed such that no leaks occur at the cast.
SUMMARY OF THE INVENTIONAn object of the invention is to present a building element for a building structure such as a floor structure, which decreases the amount of work having to be performed at the construction site.
Another object of the invention is to present a building structure which comprises less material compared to building structures for the same structural requirements and produced according to known solutions.
The first and second objects are reached with a building element for a building structure such as a floor structure, comprising a member, said member having a planar portion, comprising at least a part of a mould provided at an edge of the member.
Thereby, at the construction site, such building elements can be placed adjacent to each other. Whether mould parts or complete moulds are provided fixed to the members, these can be used to cast in situ floor beams between the planar elements. Thereby, essential structural components can be easily made at the construction site in correct positions with the aid of the moulds or mould parts provided on the building elements, which can be prefabricated. The possibility of easily producing essential load carrying members at the constructions site, makes it possible to provide prefabricated building elements that are substantially lighter than those of known methods, and therefore transportation is facilitated. Also, since the moulds or mould parts allow easy fabrication of reinforced concrete floor beams with a high flexural rigidity, a light strong floor structure, with a finished floor surface, can be obtained without the use of large quantities of concrete which result in very heavy floor structures.
Preferably, the member comprises high performance concrete. Preferably said concrete has a water-cement ratio equal to or lower than 0.39. Preferably said concrete comprises ballast material comprising an open pore structure material for receiving during heating water vapour from water in the concrete, said ballast preferably being non-combustible material. Preferably, the high performance concrete is of the type described in PCT/SE2004/000148, filed by the applicant and incorporated herein by reference. This type of concrete is very durable in a case of fire, since it does not split, as described in said PCT application. This, together with the high strength of this concrete allows for a relatively thin layer of concrete, which reduces weight, and allows the building element to be used for relatively high structural requirements. It further facilitates providing floor structures with a high flexural rigidity, a light strong floor structure, with a finished floor surface, without the use of large quantities of concrete which result in very heavy floor structures. As this type of concrete does not have the problem of creep and shrinking during hardening, does not transform due to torsional effects etc. an even or smooth surface is achieved when joining the building elements. Therefore, as a smooth floor surface is achieved, there is no need for an additional self-levelling layer of concrete, and thus there is no problem with damp. Thus there is no longer a need for drying for a long period of time. The construction process thus becomes more rapid, and cheaper due to less material used and time, i.e. work hours saved.
Preferably the member comprises reinforcement means. By having reinforcement means the structural strength is increased.
Preferably the reinforcement means comprises fibres mixed within the member. By using fibres there is no need for conventional reinforcement bars which makes the building element easier to manufacture, cheaper and lighter, and therefore transportation and handling is facilitated. The construction time is thus reduced.
Preferably the reinforcement means comprises local reinforcement units protruding out of the planar portion at the edge. This provides for, when two building elements are joined together, improved strength of the cast as the protruding reinforcement units become part of the cast beam or sealing. The units may also be attached, e.g. welded, to further improve the bond. By this, rigidity between the elements which is in the order of the rigidity of the elements themselves is obtained, thus avoiding discontinuous rigidity across element joints.
Preferably the member further comprises at least one beam portion extending from the plane of said planar portion. This further increases the prefabrication and thus decreases the amount of work having to be performed at the construction site in that less casting needs to be performed at the construction site. The amount of concrete needed at the construction site is also reduced.
Preferably the at least one beam portion extends laterally essentially perpendicular to the planar portion.
Preferably the at least one beam portion is provided at a region between the edges of the planar portion, said beam portion constituting an intermediate beam portion. This further increases the bearing strength lifting power and stability of the building element. This also facilitates making wider building elements. It further has the advantage that fixation of mould parts such as sheet profiles, if used, during assembly is simplified.
Preferably the at least one beam portion is provided at, at least one of the edges of the planar portion.
Preferably the at least a part of a mould is constituted by the beam portion. As the part of the mould is a portion of the member no fixation of the part of the mould is needed and thus workload is reduced. When two building elements are joined together to form a mould by means of respective edge beam portions, the risk of leakage due to pressure caused by concrete during casing which may be the case with conventional mould such as a steel sheet profiles joined together not entirely withstanding said pressure, is reduced. In addition, the amount of concrete needed at the construction site for casting the mould is reduced further, as this facilitates providing very small moulds. The mould is only needed for casting a sealing and stabilization of the building structure, and thus there is no need to cast a supporting beam at the construction site.
Preferably, the reinforcement means comprises at least one reinforcement member, a part of which protrudes out of the member at the edge at which the part of a mould is fixed. Thereby, if material of the member formed at the construction site by use of the mould is allowed to surround the protruding part of reinforcement members, an effective structural joining between the member and the member formed at the construction site is accomplished.
Preferably, the edge at which the part of the mould is fixed forms at least partly an additional part of the mould. Thereby, material of the member formed at the construction site by use of the mould is allowed to contact the edge of the member, and as a result of this the bond between the member and the member formed at the construction site is further strengthened.
Preferably, the part of the mould has an elongated shape. Thereby, the mould can be used to form an extended structural member, such as a floor beam, between the members.
Preferably, the member has an elongated shape, and the part of the mould extends alongside the member. Thereby, the building element can be used to span openings in a construction to form a floor structure, whereby the mould can be used to provide a structural member extending across the floor to carry loads to vertical members in the periphery of the opening.
Preferably, the part of the mould extends at least partly out of the plane of the member. Thereby, the mould can be used to form a member which has a thickness, or height, being considerably larger than the thickness of the member, as a result of which a building structure with a large flexural rigidity can be obtained.
Preferably, at least one reinforcement member is located, in relation to the part of the mould, in a position which it is intended to assume after a casting process involving the part of the mould. Thereby, reinforcement members, e.g. in the form of reinforcement bars, will be in their final position when the building element arrives at the construction site, so that the construction time can be accelerated.
Below, embodiments of the invention and their advantages will be described in greater detail with reference to the drawings, in which
The building element 1 comprises a member 10 having planar portion 10d, in this embodiment in the form of a rectangular upper plate portion 10d, and an intermediate beam portion 42a extending from a central region of the planar portion 10d. The member 10 preferably comprises high performance concrete, preferably reinforced high performance concrete of the type described in PCT/SE2004/000148, incorporated herein by reference. The beam portion 42a preferably has an I-section extending laterally essentially perpendicular to the planar portion 10d. Alternatively the member 10 may comprise more than one beam portion, preferably each beam having essentially the same configuration, i.e. extending laterally essentially perpendicular to the planar portion. Mould parts 11, 12 are fixed to the planar portion 10d at a respective longitudinal edge 10a thereof. Reinforcement means 10c in the form of reinforcement wire mesh are received in the planar portion 10d. At each edge 10a, ends 10b of reinforcement wire mesh 10c protrude. The beam portion also comprises reinforcement bars 121.
The reinforcement wire mesh 10c, 121 could be part of a fabric reinforcement cast into the planar portion 10d, as shown in
The mould parts 11, 12 are suitably made of thin sheet section beams, preferably of a standardised type, extending along the longitudinal edges of the planar portion 10d. Each mould part 11, 12 can be fixed to the planar portion 10d by an edge region thereof being cast into the planar portion 10d. For this the mould part is preferably provided with a shoulder that can be used to secure the former until casting is finalised. Each mould part 11, 12 can also be mounted to the planar portion 10d by some kind of suitable fastening arrangement, by means of for example braces or welds.
As can be seen in
Variants of the above embodiments such as combinations, i.e. with or without ceilings, different types of reinforcement means, different shapes of mould parts and beam portions etc. are possible.
Further, in the above embodiments it is referred to high-performance concrete. By high performance concrete is meant any concrete, which satisfies certain criteria, i.e. a concrete having a water-cement ratio equal to or lower than 0.39, when essentially all capillary pores in the cement paste are vanished. High-performance concrete usually comprises a cement paste mixed with fines such as micro silica and plasticizing admixtures, which increase the density and adhesiveness of the cement paste, and is characterised by high strength, waterproofness but diffusion-openness, high durability, and good carbonation and chloride resistance. Due to its improved mechanical properties, high-performance concrete is often called “high-strength concrete”. Preferably, the open pore structure material is a non-combustible material with such mechanical properties that the overall strength of the concrete is not reduced. These requirements are met by, for instance, particles in waste materials from metal production (slag), which in a preferred embodiment of high-performance concrete comprise a porous composite alloy, and exclude e.g. leca, which is weaker than granite and quartz and presents pore dimensions such, that the pores are filled with fine particles during casting.
Claims
1. A building element for a building structure, the building element comprising: a member having a planar portion; and at least a part of a mould provided at an edge of the member.
2. A building element according to claim 1, wherein the member comprises high performance concrete.
3. A building element according to claim 2, wherein said concrete has a water-cement ratio equal to or lower than 0.039.
4. A building element according to claim 2, wherein said concrete comprises ballast material including an open pore structure material for receiving during heating water vapour from water in the concrete.
5. A building element according to claim 4, wherein said ballast material is non-combustible material.
6. A building element according to claim 1, wherein the member includes reinforcement means.
7. A building element according to claim 6, wherein the reinforcement means includes specially formed fibres mixed within the member.
8. A building element according to claim 6, wherein the reinforcement means includes local reinforcement units protruding out of the planar portion at the edge.
9. A building element according to claim 1, wherein the member further comprises includes at least one beam portion extending from the plane of said planar portion.
10. A building element according to claim 9, wherein the at least one beam portion extends laterally essentially perpendicular to the planar portion.
11. A building element according to claim 9, wherein the at least one beam portion is provided at a region between the edges of the planar portion, said beam portion including an intermediate beam portion.
12. A building element according to claim 9, wherein the at least one beam portion is provided at, at least one of the edges of the planar portion.
13. A building element according to claim 9, wherein the at least one beam portion includes the at least a part of the mould.
14. A building element according to claim 6, wherein the reinforcement means comprises at least one reinforcement member, and wherein a part of the at least one reinforcement member protrudes out of the planar portion at the edge at which the part of a mould is fixed.
15. A building element according to claim 1, wherein the edge at which the part of the mould is provided forms at least partly an additional part of the mould.
16. A building element according to claim 1, wherein the part of the mould has an elongate shape.
17. A building element according to claim 1, wherein the member has an elongate shape, and the part of the mould extends alongside the planar portion.
18. A building element according to claim 1, wherein the part of the mould extends at least partly out of the plane of the planar portion.
19. A building element according to claim 14, wherein at least one reinforcement member is located, in relation to the part of the mould, in a position which it is intended to assume after a casting process involving the part of the mould.
20. A building element according to claim 1, wherein the building structure has an essentially horizontal extension.
21. A building element according to claim 20, wherein, in an intended final position of the building element, the part of the mould extends laterally downwards from the planar portion.
22. A building element according to claim 1, further comprising an additional member, the members oriented substantially parallel to each other and located at a distance from each other in a direction perpendicular to their planes, the part of the mould extending laterally from one of the members to the other.
23. A building structure comprising a building element, the building element including a member having a planar portion and at least a part of a mould provided at an edge of the member.
Type: Application
Filed: Nov 25, 2005
Publication Date: Mar 12, 2009
Inventor: Roger Ericsson (Kalmar)
Application Number: 11/791,066
International Classification: E04B 5/02 (20060101); E04B 5/17 (20060101); E04B 5/18 (20060101); E04B 5/23 (20060101);