Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
  • E04C5/01—Reinforcing elements of metal, e.g. with non-structural coatings
  • E04C5/06—Reinforcing elements of metal, e.g. with non-structural coatings of high bending resistance, i.e. of essentially three-dimensional extent, e.g. lattice girders
  • E04C5/065—Light-weight girders, e.g. with precast parts
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B5/00—Floors; Floor construction with regard to insulation; Connections specially adapted therefor
  • E04B5/02—Load-carrying floor structures formed substantially of prefabricated units
  • E04B5/04—Load-carrying floor structures formed substantially of prefabricated units with beams or slabs of concrete or other stone-like material, e.g. asbestos cement
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
  • E04C2/04—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres
  • E04C2/049—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres completely or partially of insulating material, e.g. cellular concrete or foamed plaster
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
  • E04C2/04—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres
  • E04C2/06—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of concrete or other stone-like material; of asbestos cement; of cement and other mineral fibres reinforced
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/44—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the purpose
  • E04C2/50—Self-supporting slabs specially adapted for making floors ceilings, or roofs, e.g. able to be loaded

Definitions

• the present application relates to a plate-shaped slab element. More particularly, it relates to a plate-shaped slab element for use as a floor in a building, the slab having a length defined by first end portions, a width defined by second end portions and a thickness defined by a top side and a bottom side, and the slab being supported, at least in portions of the first end portions, by a supporting element.
• the supporting element may typically be walls or a foundation of a building. It is thus to be understood that the term "floor” may cover a floor or a roof in a building, the floor being made as one single slab element or several slab elements placed side by side, as will be known to a person skilled in the art.
• such slab elements are solid elements made in reinforced concrete, wherein a plurality of elements are placed side by side to form a slab.
• Such solid elements are relatively simple to produce, but have a high density which is typically in the order of 2400-2500 kg/m 3 .
• Such a high density is encumbered with several drawbacks.
• One of the drawbacks is that handling such elements which may weigh several tonnes requires relatively powerful lifting equipment. At a building site it may be problematic to arrange access for powerful lifting equipment that might be required when the slab element is being installed.
• Another drawback related to heavy structures is restrictions on the axle pressure permitted on the road network, which may result in more trips from the manufacturer to the building site. In places where it is difficult to provide lifting equipment of sufficient capacity, the drawback of heavy, prefabricated slab elements is even greater. If, in addition, the road standard is poor, road transport may at best be challenging.
• a person skilled in the art will know that a building structure that includes building elements of a high dead load, for example the above-mentioned solid slab elements, may be considerably more vulnerable than structures having a lower density in natural disasters such as earthquakes. This, together with the infrastructure and limited access to suitable lifting equipment, may be an explanation of the fact that there is relatively little use of slab elements of the above-mentioned kind in some countries and regions.
• plate-shaped slab elements as so-called hollow-core slabs, in which a portion of the concrete has been replaced with cut-outs or channels so that the total weight of the element is reduced.
• filigree slabs which include reinforced concrete, but which may include lightweight concrete, for example EPS concrete, between a top portion and a bottom portion.
• the reinforcement will be provided by means of so-called lattice girders which connect the top portion to the bottom portion.
• a variant of such a filigree slab is a structure which is sold under the name of Bubble- Deck ® and which is a concept developed relatively recently.
• a BubbleDeck® includes relatively large balls, typically in plastic, which are placed between two layers of reinforced concrete. Concrete is filled between the balls and over these after the balls and reinforcement have been disposed over a bottom supporting layer of cured concrete.
• a hollow-core slab is relative complicated to produce as the formwork must include pipes or channels typically extending between the end portions in the longitudinal direction of the slab.
• the channels must be disposed with great accuracy.
• An advantage of a hollow-core slab is that the channels may be used as channels for pipes and wires.
• a filigree slab is relatively time-consuming in manufacture, given that the manufacturing must typically be performed in three operations: first casting the bottom portion, and after this has been sufficiently cured, reinforcing and filling light-weight concrete, for example, and after this has been cured, depositing the concrete top layer.
• a wall element cast in ultra-lightweight concrete containing at least 50 per cent by volume of expanded plastic material is known.
• the wall element is provided with a mesh reinforcement forming anchoring for lifting members.
• a slab element is described, having, in the main, tensile reinforcement and four lifting members anchored to the tensile reinforcement.
• a wall element cast in lightweight concrete with expanded polystyrene is known.
• the wall is reinforced on both sides with a mesh reinforcement and reinforced with at least two girders.
• the invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.
• a plate slab may be produced exclusively from so-called EPS concrete and reinforcement, even though EPS concrete has a relatively poor load-carrying capacity with respect to compressive stress, which is a very important property of a concrete structure.
• the compressive strength of EPS concrete is about 20 % of the compressive strength of ordinary concrete of the kind used in solid slab elements.
• EPS concrete consists of in the order of 80 % by volume of particulate expanded polystyrene and only about 20 % by volume of cement and water, and also about 0.1 % by volume of organic or animal protein to provide bonding of the cement to the polystyrene in order thereby to provide a homogenous mass.
• the aggregate in EPS concrete is particulate expanded polystyrene.
• the aggregate in EPS concrete may thus be produced by recycling polystyrene that has been used for other purposes such as protective packaging.
• ESP concrete thus has a positive environmental aspect.
• the density of an ESP concrete of the kind mentioned is in the order of 300-350
• the applicant has also conducted tests with the admixture of an aggregate such as sand into the EPS concrete. This is primarily to increase the tensile strength and the compressive strength of the concrete. In one test, a 100 kg/m 3 EPS concrete was used. The density of such an EPS concrete with added sand will thus be 400-450 kg/m 3 .
• the applicant has further performed tests with mixing reinforcing fibres into pure EPS concrete, and into EPS concrete with added sand as mentioned above, to reduce the risk of cracking and to increase the elasticity of the concrete.
• the reinforcement may thus include fibres in addition to reinforcement made by the use of steel rods of the kind that will be explained in what follows.
• the fibre reinforcement may be produced from steel fibres, fibre glass or a magmatic rock such as basalt, or any mixture of these. In one test, approximately 15 kg of fibre reinforcement of steel was used per m 3 of concrete.
• a plate-shaped slab element for use as a floor in a building, the slab having a length defined by first end portions, a width defined by second end portions and a thickness defined by a top side and a bottom side, the slab element being made from concrete with an aggregate comprising an expanded plastic material, and the slab element being provided with reinforcement comprising an upper mesh reinforcement and a lower mesh reinforcement, and the slab element being supported, at least in portions of the first end portions, by a supporting element.
• the slab element includes at least two spaced-apart lattice girders, each extending at least in a two-dimensional extent between the first end portions, the at least two spaced-apart lattice girders being connected at an upper portion and at a lower portion to the upper mesh reinforcement and the lower mesh reinforcement, respectively, and that all reinforcement is embedded in concrete of the kind in which the aggregate of the concrete comprises particulate expanded polystyrene.
• the aggregate of the concrete consists exclusively of particulate expanded polystyrene.
• EPS concrete concrete of the kind in which the aggregate of the concrete consists of particulate expanded polystyrene will also be referred to as EPS concrete.
• the use of EPS concrete as a material in addition to reinforcement has the effect of the plate element achieving a density in the order of 20-25 % of that of a corresponding slab made from solid, reinforced concrete, and in the order of 40-50 % of that of a corresponding slab made as a filigree slab.
• the reduced density will, in turn, have the posi- tive effect of allowing the amount of reinforcement to be reduced in relation to that necessary for a corresponding slab of a higher density.
• a reduced amount of reinforcement will, in turn, have a positive effect on the overall weight of the structure.
• the lattice girders embedded in the EPS concrete are stabilized against buckling on compressive stress by both the EPS concrete and the upper and lower mesh reinforcements. It is therefore important that each of these is firmly fixed to the lattice girders. Adhesion between the EPS concrete and the reinforcement ensures exploitation of the tensile capacity of the reinforcement.
• the two-dimensional lattice girder may be formed of wire and comprises a lower chord, an upper chord and diagonal members extending in zigzags between the lower chord and the upper chord between the first end portions.
• the purpose of the diagonal members is to absorb shear forces.
• the lattice girder may extend in a three-dimensional extent between the first end portions. This has the effect of increasing the buckling capacity in relation to that of a two-dimensional lattice girder, among other things.
• Such a three-dimensional lattice girder may be formed of wire and comprises a lower chord, an upper chord and diagonal members extending in zigzags between the lower chord and the upper chord, at least one of the upper chord and the lower chord comprising two spaced-apart wires. Seen from an end portion, the at least two lattice girders that are arranged in a spaced-apart manner may thus exhibit a V-shape or a ⁇ -shape, or a combination thereof.
• the joint may be provided by means of welding.
• a method of producing a plate-shaped slab element according to the first aspect of the invention including:
• the desired position in the formwork is meant, among other things, that the reinforcement is disposed with the desired so-called concrete cover.
• the method may include using aggregate which consists exclusively of particulate expanded polystyrene. Such a method may be particularly relevant when there is a need for a plate-shaped slab element with the lowest possible dead load.
• the method may further include removing the formwork after the concrete mass has cured at least partially.
• removing the formwork after the concrete mass has cured at least partially.
• at least a portion of the form- work is maintained in order thus to constitute part of the final building structure.
• the formwork may be produced from a suitable material such as materials based on wood or wood fibre, a synthetic material, a metal or from a combination of two or more thereof.
• a formwork of metal and/or a synthetic material such as plastic based on fibre glass could be used as an outer skin in a roof, for example. After pouring and curing, the slab element must be mounted "upside down”, rotated 180° around its longitudinal axis, that is.
• a third aspect of the present invention relates to the use of concrete with an aggregate comprising particulate expanded polystyrene, so-called EPS concrete, in a reinforced, plate-shaped slab element according to the first aspect of the invention.
• the third aspect thus relates to the production of a plate-shaped slab element comprising EPS concrete and reinforcement.
• Figure 1 shows a typical plate-shaped slab element according to the present invention, viewed from a top side, in which lattice girders are shown in broken lines;
• Figure 2 shows the slab element of figure 1 in a sectional view through I-I of figure 1, the slab element being supported in two end portions by a supporting element;
• Figure 3a shows a section through the line II-II in figure 1 on a larger scale
• Figure 3b shows an alternative embodiment of the lattice girder shown in figure
• Positional specifications such as over, under, upper, lower, right and left, refer to the positions that are shown in the figures.
• the reference numeral 1 indicates a plate-shaped slab element according to the present invention.
• the slab element 1 is of the kind that is well suited as a floor in a building, the floor also to be understood as possibly comprising a floor on a ground or a roof.
• the slab element has a length L which is defined by first end portions 3, 3' and a width B defined by second end portions 5, 5'. In the embodiment shown, the length L is larger than the width B.
• the slab element has a thickness T which is defined by a top side 7 and a bottom side 7'.
• the slab element is produced from EPS concrete 9 which encloses several spaced- apart lattice girders 11 (five shown in figure 1).
• the lattice girders 11 extend between the first end portions 3, 3'.
• Figure 1 and figure 2 show a lattice girder 11 extending in zigzags both in the width and in the height between the first end portions 3, 3'.
• An upper mesh reinforcement 17 is fixed by means of weld connections to an upper portion 11' of the lattice girder 11.
• a lower mesh reinforcement 19 is fixed by means of weld connections to a lower portion 11" of the lattice girder 11.
• the lattice girder 11 comprises a lower chord 13, an upper chord 15 and diagonal members 18 extending in zigzags between the lower chord 13 and the upper chord 15 along the length L of the slab element.
• the lattice girder 11 is shown in a first, three-dimensional variant.
• the lattice girders 11 are shown arranged alternatingly in a ⁇ -shape and a V-shape.
• the lattice girder 11 in a ⁇ -shape (three shown in figure 3a) is provided, in its lower portion 11", with two lower chords 13 arranged in parallel and in a spaced-apart manner.
• the lattice girder 11 In its upper portion 11', the lattice girder 11 is provided with one upper chord 15.
• the diagonal members 18 are "wrapped” in zigzags around the longitudinal axes of the chords 13, 15.
• the lattice girder 11 in a V-shape (two shown in figure 3a) is provided, in its lower portion 11", with one lower chord 13.
• the lattice girder 11 is provided with two upper chords 15 arranged in parallel and in a spaced-apart manner.
• the diagonal members 18 are wrapped in zigzags around the longitudinal axes of the chords 13, 15.
• the lattice girder 11 is shown in a second two-dimensional variant, in which the lower chord 13 consists of one wire, and the upper chord 15 consists of one wire.
• the diagonal members 18 are wrapped in zigzags along the longitudinal axes of the chords 13, 15, as shown in figure 2.
• the solution in figure 3b is particularly suitable for housing one or more channels 27 (only one shown) in a manner corresponding to that of a hollow-core slab.
• Such channels 27 will further reduce the weight of the slab element 1, but are not as important as in a hollow-core slab made from ordinary concrete.
• the channels may be useful as guiding channels for pipes and wires.
• hoisting attachments 21 (four shown in figure 1) of a kind known per se are attached to the reinforcement 11, 17 before EPS concrete is disposed around this.
• a slab element according to the present invention has turned out to present sensationally good results.
• a mesh reinforcement of the k-131 type was used for the upper mesh reinforcement 17 and the lower mesh reinforcement 19.
• the slab element had a weight of approximately 850 kg and was supported on a foundation similar to the foundation 25 shown in figure 1.
• the density of the reinforced slab element was in the order of approximately 400 kg/m 3 .
• the slab element was first loaded with a concentrated load of 1000 kg positioned centrally, which was the load for which the slab element was dimensioned. The maximum deflection was then measured to be 1.5 cm. With a load of 2000 kg positioned in a corresponding manner, the deflection was measured to be 3 cm, and with 3 tonnes to be 4.5 cm.
• the slab element exhibited very good elastic properties in that the slab resumed its original shape on removal of the load and in that no visible cracks were observed.
• Slab elements according to the invention can be assembled without the use of special machines as is the case of, for example, hollow-core slabs. This entails the possibility of making the slab elements 1 at or near the building site where they are to be used. This is particularly favourable in places in which transport of prefabricated elements may present problems, for example where the road network is not suitable for heavy transport.
• the low density of the slab element 1 is also positive with respect to use in regions that are prone to earthquakes as mentioned initially.
• the low weight gives a reduced horizontal stress on the building structure while the earthquake is in progress, which may, in turn, be turned to account to substantially simplify the structure, as will be known to a person skilled in the art.
• the slab element 1 according to the invention may present advantageous features with respect to searches for survivors and lifesaving work, and to subsequent clearing work. This is because the slab elements 1 will, to a great degree, be movable by means of hand power without the use of lifting devices which have turned out to be very challenging to get into place quickly in such catastrophes.
• the low density of the slab element 1 may also be very advantageous when buildings are being erected in places where there is no access for lifting devices or lifting devices are not available. Further, the strain on foundations and walls will be reduced.
• EPS concrete Another positive property of EPS concrete is that it has a very good heat-insulating effect and exhibits very good fire resistance.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Reinforcement Elements For Buildings (AREA)
• Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
• Measurement Of Radiation (AREA)
• Forms Removed On Construction Sites Or Auxiliary Members Thereof (AREA)

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• 2015
  • 2015-05-27 NO NO20150675A patent/NO339881B1/no unknown
• 2016
  • 2016-05-04 WO PCT/NO2016/050083 patent/WO2016200267A1/en active Application Filing

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