Floor slab, load-bearing structural system comprising the floor slab, and method of assembly of the system

Abstract

Disclosed herein is a floor slab (1) for a load-bearing structural system (100) of a building, the load-bearing structural system (100) and a method of assembly for said system (100) The floor slab comprises a load-bearing plate-shaped member (2) having at least three corners (21) and at least three side faces (22). A coupling member (3) is arranged at each of the corners (21) for connecting each corner to a load-bearing component (7) of the structural system (100), each coupling member being fixedly connected to a corner of the load-bearing plate-shaped member and protruding from respective corner faces (23). The coupling member (3) is adapted for being detachably connected to a complementary coupling member (71) of the load-bearing component (7) and for transferring load from the floor slab (1) to the load-bearing component (7).

Description

[0001] FLOOR SLAB, LOAD-BEARING STRUCTURAL SYSTEM COMPRISING THE FLOOR SLAB, AND METHOD OF ASSEMBLY OF THE SYSTEM

[0002] The invention concerns a floor slab for a load-bearing structural system of a building. The invention further concerns the structural system, the building, and also a method of assembly of the load-bearing structural system. More specifically, the invention concerns a floor slab having load-bearing properties, and a load-bearing structural system which comprises the floor slab, load-bearing components for instance columns, and means for fastening the floor slab to said load-bearing components.

[0003] The construction industry is one of the world's largest industries. Considering the number of buildings and building types raised worldwide, it is also an industry which severely impacts the environment, and which uses a lot of resources.

[0004] Although there is an increased focus on reuse and recycling, this is often associated with time- and energy consuming processes of sorting and transporting construction elements for subsequently decomposing them into their constituent parts which new construction elements can be produced from.

[0005] Another challenge in the construction industry is that construction projects often have deadlines, and a lot of different personnel is involved in the building process. Time-saving construction solutions are therefore welcome, at the same time as rules and regulations must be complied with.

[0006] The use of prefabricated construction parts is a well-established way of reducing the problem of emissions and waste on the building site, as well as speeding up construction projects.

[0007] However, there are still some major problems to be solved. One is to efficiently be able to re-use construction elements without having to decompose and recycle them. Another is to be able to construct a building and later disassemble and move the building, using the same construction elements. And a third is to further reduce construction time, use of materials, and the number of different construction elements necessary.

[0008] Patent publications US3780480A, NL9000820A and CN107435375B all show prefabricated, load-bearing floor slabs for at least partly solving some of the problems mentioned above.

[0009] US3780480A discloses a building construction which utilizes post-tensioned columns and pre-cast concrete horizontal floor slabs.

[0010] Patent publication NL9000820A discloses a load-bearing construction system wherein concrete slabs rest on concrete columns. However, in order not to exert any forces from the storeys above the concrete slabs, an upper column is connected to the lower column solely through a metal portion arranged between facing ends of the columns, and independently of the floor slabs.

[0011] Patent publication CN107435375B discloses a building system having prefabricated reinforced concrete components. This publication addresses the problems of long construction time, waste and difficulties reusing materials. A column is provided with ears for hanging wall panels and arc-shaped slots for complementary fitting with arc-shaped protrusions arranged in the corners of floor slabs.

[0012] Patent publication PR 2142887 A1 discloses a system of elements for constructing a supporting framework of a building. The system includes different types of floor slabs which are connected at the corners to supporting posts. Corner portions of the slabs are arranged outside of, and partly enclosing, the posts, while resting on a cantilever of the posts.

[0013] The object of the invention is to provide a solution to at least one of the problems mentioned above. In particular, it is an object of the invention to provide a load-bearing floor slab which can be re-used as it is. The floor slab is arranged to be removably connected to other members of a load-bearing structural system of a building. Further, it is an object of the invention to provide a complete load-bearing structural system for a building, wherein all the elements of the system are made so that the system can be assembled and disassembled multiple times.

[0014] By load-bearing floor slab is in this context meant a floor slab which is self-bearing and which do not rely on beams for support. In a first aspect, the invention concerns a floor slab for a load-bearing structural system of a building, the floor slab comprising:

[0015] - a load-bearing plate-shaped member having at least three corners and at least three side faces; and

[0016] - a coupling member arranged at each of the corners for connecting each corner to a load-bearing component of the structural system, wherein the corners are cut corners each defining a corner face connecting two adjoining side faces; wherein each coupling member is fixedly connected to the load-bearing plate-shaped member and protruding from the respective corner face, and wherein the coupling member is adapted for being detachably connected to a complementary coupling member of the load-bearing component and for transferring load from the floor slab to the load-bearing component.

[0017] The present floor slab is constructed so that, in a position of use, the load it carries is transferred via the coupling element in each corner of the slab and onwards to a connected load-bearing component.

[0018] In the following, for the sake of readability, the load-bearing component which the floor slab is arranged to be connected to, is referred to as a column. However, as will be explained in the following, the term “load-bearing component” of the structural system may also include shaft walls or other load-bearing components for being arranged in an upright position and for being provided with one or more complementary coupling members for connecting to one of the coupling members of the floor slab. This way, load from the floor slab is transferred to the upright load-bearing components via the coupling members.

[0019] Prior art floor slabs are generally connected to a structural system in one of two ways. Either the floor slabs typically rest on beams or otherwise they rest on an end portion of the column they are connected to.

[0020] One disadvantage of a system of the first type, is the need for a complex structure of beams and columns having to be in place before floor slabs can be installed. The beams are also space-requiring and add to the required gross height needed between levels to accommodate sufficient space for technical infrastructure. In some systems beams are partially integrated in the floor slab construction but the latter disadvantage of being space-requiring and adding to the gross height needed, will still be there. This also causes longer construction time, more building elements, and the need for scaffolding for placing the floor slabs.

[0021] A disadvantage of the second type is that part of the floor slab area is “lost” between lower and upper column parts, causing poor area efficiency and possibly also unfortunate stress on the corner portions of the floor slabs. Such a system also requires quite bulky columns, which means more material used.

[0022] In addition to eliminating the need for conventional beams, the present floor slabs also provide a more area efficient solution. By providing the plate-shaped part of the slab with cut corners and arranging load-transferring coupling members protruding from the corner faces, the floor slabs can be placed adjoining each other and be coupled to the complementary coupling member of the load-bearing component only by means of the protruding portion of the slab’s coupling member. The load-bearing plate-shaped member of the floor slab, which is the actual “floor portion" of the floor slab, will therefore not be sandwiched between the other construction elements as in prior art. Instead, a slim connection point is provided at the corners of the floor slab. This way the floor slab according to the first aspect, represents a material effective solution.

[0023] To sum it up, the feature that the coupling member protrudes from the corner face of the plate-shaped member, has at least four advantages. First, the coupling member does not take up any space at the side faces of the plate-shaped member, which means that two neighbouring plate-shaped members may be placed in contact with each other without hindrance. This makes for an area and material efficient solution, where no extra “filling” is needed between floor slabs. Second, when placing two floor slabs next to each other this way, side faces in contact, the coupling members protruding from respective corner faces of the two plate-shaped members will extend towards the same point and may thus be connected to the same complementary coupling member of the load-bearing component. This makes for a very slim connection point which exerts little to no constraining forces on the load-bearing component. Third, arranging the coupling member at the corners this way, allows for a structural system having very few necessary components. In its simplest form only load-bearing components in the form of for example columns and floor slabs connected directly to the columns, are necessary. This reduces both construction time, use of materials and complexity of the structural system which the floor slab forms part of. And fourth, the structural system of the building may be built from within, and one floor at a time, meaning that no scaffolding is necessary on the outside of the building. When two or more upright load-bearing components are arranged on top of each other, which will be explained in more detail below when discussing the structural system, the coupling member of the floor slab may be sandwiched between complementary coupling members of two load-bearing components.

[0024] The coupling member of the floor slab may be sandwiched between a top complementary coupling member arranged on a top end of a first column and a bottom complementary coupling member arranged at the bottom of a second column stacked on top of the first column.

[0025] This solution allows for a quicker and easier assembly of floor slabs to other components of a load-bearing structural system of a building, and it also provides easy disassembly of the system since the floor slabs and other load-bearing components are not fixed to each other by concrete, through-going reinforcement bars or other means which can only be disassembled by breaking it. The present floor slab is therefore re-usable as it is.

[0026] Each coupling member of the floor slab may be fixedly connected within the load-bearing plate-shaped member. Fixing the coupling member within the floor slab has the effect of strengthening the corner portion of the floor slab by means of the coupling member itself.

[0027] Each coupling member of the floor slab may extend within a coupling area defined by the respective corner face and an imaginary extension of the two respective side faces of the load-bearing plate-shaped member.

[0028] The coupling member may be essentially flat. In a position of use, a portion of the coupling member which protrudes from the corner face, may be arranged horizontally for being coupled with the complementary coupling member of the load-bearing component or sandwiched between two complementary coupling members of load-bearing components arranged on top of each other.

[0029] The coupling member may be anchored or securely fastened within the plate-shaped member.

[0030] The load-bearing plate-shaped member may be made of wood, composite material, clay material such as terracotta, or concrete, and may further comprise reinforcement.

[0031] The coupling member may be arranged in connection with the reinforcement. In one embodiment the load-bearing plate-shaped member may be a concrete plate comprising reinforcement, and the coupling member may be arranged in connection with the reinforcement for efficient transfer of load from the reinforcement via the coupling member to the load-bearing component when the floor slab is in a position of use, i.e., typically arranged horizontally.

[0032] The load-bearing plate-shaped member of the floor slab may be made of a variety of materials such as solid wood, composite materials, reinforced terracotta, or other clay materials. Also, the floor slab may be a hybrid of different materials, for example wood and metal (reinforcement). The skilled person will understand that the plate-shaped member needs to be constructed so that it can withstand the forces acting on it during use. The skilled person will also, by means of known engineering calculations, be able to choose the best floor slab material for a given construction.

[0033] Concrete has some useful properties, like being fireproof and sound-absorbing which makes it a preferable material for multi-storey buildings.

[0034] The reinforcement may comprise primary reinforcement and secondary reinforcement. The coupling member may be arranged in connection with the primary reinforcement.

[0035] The floor slab may preferably be prefabricated. Prefabricated elements are advantageous in that they may be mass produced at a suitable location. Also, using prefabricated elements save a lot of time during the actual construction period. Another advantage of prefabricated elements is that they can be checked for defects and tested before use. For prefabricated floor slabs, the production may be robotized, and a very high standard of precision may be achieved.

[0036] The load-bearing plate-shaped member may be form-cast. The coupling member and any reinforcement may be arranged in place in the form before casting of the plate-shaped member.

[0037] The coupling member may be a bracket.

[0038] The coupling member may typically be made of steel. However, as the skilled person will appreciate, the coupling member is made of a material which is suitable for receiving and transferring the forces exerted on it from the plate-shaped plate member and from the column, wall, or other load-bearing component of the structural system. A steel bracket is considered an example of a possible coupling member. By “plate-shaped member” is typically meant a plate having a top face, a bottom face parallel to the top face, and a thickness. A mid-plane runs parallel to the top face and bottom face. As already defined hereinabove, the plate-shaped member has at least three side faces and three cut corners, where a corner face connects adjoining side faces. Note that the term “coupling area” is used herein for the area defined by the corner face and an imaginary extension of the two respective side faces. By imaginary extension of the side faces, is herein meant a straight line drawn in the extension of each of the two side faces connected by the corner face in question, until the point where the two lines meet. The area between these two lines and the corner face, is the “coupling area”.

[0039] The plate-shaped member with cut corners may have a mainly triangular shape, a mainly four-sided shape such as square or rectangular, or a multi-sided shape. For practical reasons, the plate-shaped member will in the following be referred to, and shown, as a mainly square member with cut corners.

[0040] The coupling member may have a thickness which is smaller than the thickness of the plate-shaped member, i.e., the coupling member may be relatively thin compared to the plate-shaped member.

[0041] One effect of having a coupling member which is thin relative to the plate-shaped member, is that the connection between the floor slab and the column may be “hidden” and therefore also protected from fire and wear and tear, by being below floor-level. The thin coupling member also leaves room for example for sound-absorbing means.

[0042] The coupling member may preferably protrude from the mid-plane of the plate-shaped member.

[0043] The coupling member may protrude perpendicularly to the corner face. The coupling member may protrude within the coupling area. The coupling member may protrude towards a crossing line between the imaginary extension of two side faces within the coupling area.

[0044] The coupling member may be provided with a cut corner and thus leaving space between the coupling member and the crossing line between the imaginary extension of two side faces within the coupling area. This space may allow for access to the level below the floor slab, after installation of the floor slab.

[0045] Having the protruding part of the coupling member extend as far out as possible within the coupling area, maximises a contact surface between the coupling member of the floor slab and the complementary coupling member of the column. This feature may be combined with the feature of providing the coupling member with a cut corner, i.e., maximising the contact surface within the limitation of also leaving some free space within the coupling area.

[0046] In a second aspect, the invention concerns a load-bearing structural system for a building, the load-bearing structural system comprising:

[0047] - a floor slab according to the first aspect of the invention; and

[0048] - a plurality of load-bearing components, each comprising at least one coupling member complementary to the floor slab’s coupling members; wherein the coupling member of the floor slab is adapted for being detachably connected to the complementary coupling member of the load-bearing component and for transferring load from the floor slab to the load-bearing component.

[0049] The load-bearing structural system may further comprise fastening means for detachably connecting each of the floor slab’s coupling members to a respective complementary coupling member.

[0050] One of the advantages of this load-bearing structural system, is that the floor slabs are connected to load-bearing components at its corners, and the detachable connection allows the system to be assembled and disassembled multiple times. This makes the system flexible and allows for moving buildings relatively easily.

[0051] The plurality of load-bearing components may include a column and / or a shaft wall. The system may comprise a plurality of floor slabs.

[0052] Typically, the load-bearing components are for being arranged in an upright position, i.e., the load-bearing components may be elongated components, which in a position of use are arranged vertically.

[0053] The complementary coupling member may be a flange. In a position of use, the complementary coupling member may be arranged horizontally, for providing a horizontal connection with the coupling member of the floor slab, when the system is installed. A horizontal connection allows for the best possible load transfer.

[0054] The complementary coupling member may, in a position of use, protrude horizontally from the respective load-bearing component. The load-bearing components, when arranged in an upright position, have a top and a bottom, and both the top and the bottom may be provided with a coupling member complementary to the floor slab’s coupling member.

[0055] When erecting a multi-storey building, first load-bearing components like columns may be erected on a foundation at the construction site carefully spaced apart to fit the size of the floor slabs to be supported by the columns. Thereafter, floor slabs may be arranged horizontally and positioned so that each of the protruding coupling members are brought to contact with a respective complementary coupling member at the top of the columns. This constitutes one storey of the building. For building a second storey, second loadbearing components, such as second columns, having a complementary coupling member at least at their bottom end, may then be erected directly on top of the first loadbearing components. The protruding portion of the slab’s coupling member will then be sandwiched between the top end complementary coupling member of the first column, and the bottom end complementary coupling member of the second column. Fastening means may be used to detachably secure the sandwich coupling.

[0056] The load-bearing structural system disclosed herein, may be referred to as a floor-based load-bearing system, since the floor slabs themselves have load-bearing properties. A floor-based system is a system without the conventional beam-and-column structure.

[0057] In general, in a floor-based load-bearing construction the column represents a critical component. Due to area-efficiency its dimensions are minimized according to the stresscapacity of the material used, and the buckling length of the column.

[0058] A sandwich-connection as disclosed herein, wherein the coupling elements are connected by fastening means removed from the compression area and therefore not weakens it, is an advantageous solution. The protruding coupling members, like brackets, extend almost to the centre of the column and causes minimal eccentricity which would affect the buckling length of the column.

[0059] Still bear in mind that by column, is herein also referred to other upright load-bearing components of the system, as mentioned hereinabove.

[0060] As mentioned, the complementary coupling member of a column may extend out from the perimeter of the column and be arranged to be connected to one or more floor slabs. One example, if square slabs are used, is that each complementary coupling member may be connected to four floor slabs enclosing the column. The system may further comprise a supplementary coupling element and / or a supplementary mounting bracket. The supplementary coupling element may be used to “fill in” an open portion in a sandwich-connection between one or more floor slab coupling elements and an upper and a lower complementary coupling member of two columns. In an example, maybe only two floor slabs are connected to the two coupling members. A supplementary coupling element could then fill the space between the complementary coupling members, to allow for an even load distribution in the sandwich-connection. This is further explained below, when discussing the drawings.

[0061] Supplementary coupling elements may further be provided with mounting means for connection with other elements which are not part of the present load-bearing system and will not be further discussed herein. Such supplementary coupling elements with mounting means, are referred to herein as supplementary mounting brackets.

[0062] The system may further comprise a beam. In the present system, such a beam may be provided to allow for a larger span between columns or other upright load-bearing components. Such beam may be provided with a complementary coupling member for connection with floor slab coupling member.

[0063] The system may further comprise a bracing member, such as tension rods for cross bracing.

[0064] The system may further comprise a foundation unit for positioning the load-bearing components of the system on a foundation at a building site.

[0065] In a third aspect, the invention concerns a building comprising the load-bearing system according to the second aspect. The building may be a multi-storey building.

[0066] In a fourth aspect, the invention concerns a method for assembly of the load-bearing structural system according to the second aspect, the method comprising the following steps:

[0067] - providing a floor slab according to the first aspect;

[0068] - erecting a plurality of load-bearing components on a foundation, each load-bearing component comprising a top end coupling member complementary to the floor slab’s coupling members; and

[0069] - arranging the floor slab so that each of the slab’s coupling members overlaps one of the complementary fitting top end coupling members of one of the load-bearing components. The method may further comprise the step of erecting second load-bearing components directly on top of the erected first load-bearing components to form sandwich-connections wherein each of the floor slab’s coupling members are sandwiched between two complementary coupling members.

[0070] In the following, the invention will be illustrated and explained by way of examples.

[0071] The accompanying drawings are described in detail below, where: shows a floor slab;

[0072] Figs. 2a and 2b show further details of the floor slab of Fig. 1 ;

[0073] Figs. 3a and 3b show an example of reinforcement in a reinforced floor slab such as a concrete floor slab;

[0074] Fig. 4 shows a load-bearing structural system;

[0075] Fig. 5 shows a load-bearing shaft wall for the structural system;

[0076] Fig. 6 shows in an exploded view, a connection between floor slabs and a column of the load-bearing structural system;

[0077] Fig. 7 shows a coupling member of a load bearing component of the structural system;

[0078] Fig. 8 shows an example of a supplementary coupling element;

[0079] Fig. 9 shows an example of a load-bearing structural system of a building;

[0080] Fig. 10 shows another example of a load-bearing structural system of a building;

[0081] Fig. 11 shows a cross-sectional view of a beam;

[0082] Fig. 12 shows, in an orthographic view from below, a coupling between four floor slabs, a column and a beam;

[0083] Fig. 13 shows, in an orthographic view from above, a coupling between four floor slabs and a beam;

[0084] Fig. 14 shows an example of a coupling for a foundation unit; Fig. 15 shows an example of a connection of the structural system to a foundation unit; and

[0085] Figs. 16a-16c show examples of supplementary coupling elements with additional functions.

[0086] Any position indications refer to the position shown in the Figures. In the Figures, same or corresponding elements are indicated with the same reference number. It must be understood that the Figures are principle sketches only. Relative proportions between elements in the Figures may be distorted.

[0087] Reference is first made to Fig. 1 which shows a load-bearing floor slab 1 . The floor slab 1 comprises a plate-shaped member 2 having at least three corners 21 and at least three side faces 22. The floor slab 1 shown in the Figures has a generally square shape, thus having four side faces 22 and four corners 21 . As mentioned above, the floor slab 1 may have other shapes, such as rectangular or triangular. Arranged at each corner 21 , there is a coupling member 3 for connecting each corner 21 of the floor slab 1 to a load-bearing component 7 (see Fig. 4). The coupling member 3 is shown in the form of a corner bracket 3.

[0088] The corners 21 of the plate-shaped member 2 are cut corners 21 , each defining a corner face 23 between two adjoining side faces 22. Each corner face 23 connects two side faces 22. Each corner bracket 3 protrudes from a respective corner face 23, so that, in this embodiment, a portion of the bracket 3 is securely fastened within the plate-shaped member 2 and another portion of the bracket 3 extends into a coupling area 24 (best seen in Fig. 2b). The coupling area 24 is defined by the corner face 23 and an imaginary extension of the two respective side faces 22 as shown in Fig. 2a and in more detail in Fig. 2b by means of dotted lines extending from the side faces 22.

[0089] In a preferred embodiment, and as shown in the Figures, each corner bracket 3 may be arranged at a midplane of the plate-shaped member 2. The corner bracket 3 is shown centrically arranged for protruding towards an imaginary corner line 25 (indicated by a dotted line) of the coupling area 24. The corner bracket 3 is here provided with a cut corner 31 , leaving space between an outer edge of the corner bracket 3 and said corner line 25 of the coupling area 24. When four slabs 1 are placed next to each other for connecting each of them to the same load-bearing component 7, the cut corners of the corner brackets 3 leave a typically square opening in the middle. This opening can be used for instance for inspection and / or access to the construction below. Also, the corner brackets 3 are shown to be considerably thinner, i.e., having a smaller thickness h, than a thickness H of the plate-shaped member 2 (best visible in Fig. 2b). Placing the brackets 3 this way, extending along the mid-plane of the plate-shaped member 2, allows for an advantageous coupling to the load-bearing component 7, as will be further elaborated on when discussing Fig. 6 below.

[0090] Also shown in Fig. 2a, is a network of dotted lines meant to illustrate reinforcement 5 if the plate-shaped member 2 comprises a reinforced material such as reinforced concrete or any other reinforced material such as composite materials, reinforced terracotta, or other clay materials. The reinforcement 5 may comprise primary reinforcement 51 and secondary reinforcement 52 arranged roughly as indicated in Fig. 2a.

[0091] Fig. 3a shows an example of how the primary reinforcement 51 may be anchored to the corner bracket 3. In this embodiment, the primary reinforcement 51 comprises lower reinforcement rods 510 and upper reinforcement hoops 511 . The lower reinforcement rods 510 run between corner brackets 3 along the sides of the plate-shaped member 2 and are securely fastened to an underside of the bracket 3 in use. The lower reinforcement rods 510 run parallel to respective side faces 22 and each reinforcement rod 510 connects two brackets 3. The lower reinforcement rods 510 are tension rods 510.

[0092] The upper reinforcement hoops 511 can best be seen in Fig. 3b. The hoops 511 extend from the corner bracket 3 and along the sides of the plate-shaped member 2 but are mainly arranged in an area near the corners 21 to strengthen the corners 21 . The upper reinforcement hoops 511 are securely fastened to a top side of the bracket 3 in use.

[0093] Also seen in Fig. 3b is the secondary reinforcement 52 which may comprise a reinforcement mesh 521 in connection with the lower reinforcement rods 510 of the primary reinforcement 51 .

[0094] For lifting purposes, a lifting pin 53, also called a dogbone anchor within the field, may be arranged near the corners 21 of the plate-shaped member 2, one at each corner 21 . The lifting pins 53 will protrude up from the concrete (or other material). To make sure the floor slab 1 is not damaged by lifting the floor slab 1 at the lifting pins 53, the area around the lifting pins 53 are strengthened by additional reinforcement 531.

[0095] It must be understood that reinforcement 5 is only necessary when and if the plate-shaped member 2 of the floor slab 1 is made of a material requiring reinforcement, i.e., a material which does not in itself have the required load-bearing properties necessary for the actual load it is supposed to bear. This means that depending on the size of the floor slab 1 , the present load, and the choice of materials, reinforcement 5 may or may not be present. The skilled person will use common general knowledge to compute the necessary reinforcement. Further details on this, will therefore not be provided herein.

[0096] The floor slab’s load-bearing properties are due to the plate-shaped member 2 being loadbearing either by way of a reinforced material as mentioned above, or by being made of a solid material having load-bearing properties itself. Either way, the corner brackets 3 are anchored to the plate-shaped member 2 for transferring loads to the load-bearing component 7.

[0097] The size of a floor slab 1 is typically 3x3 metres, but can also be made in other sizes, like 2x2 metres, or 2x3 metres, or larger as well, for example 4x4 metres. However, the size of the floor slabs 1 should not exceed a size which is reasonably easy to transport. Also, there are physical limitations when it comes to self-supporting load-bearing properties of a large floor slab. These limitations will depend on the choice of materials used in the floor slab 1 , as the skilled person will know.

[0098] In the case of triangular floor slabs 1 , the floor slab 1 is typically a rectangular triangle, but other types of triangular floor slabs 1 are also conceivable. Like the square or rectangular floor slabs 1 , such triangular floor slabs 1 also have cut corners 21 and corner brackets 3 extending into the previously mentioned coupling area 24.

[0099] Fig. 4 shows a load-bearing structural system 100 for a building. The system 100 is here shown having four floor slabs 1 and a plurality of load-bearing components 7 provided with coupling members 71 complementary to the coupling members 3 of the floor slabs 1 . The load-bearing components 7 are here shown in the form of columns 8. The loadbearing components 7 are arranged for being positioned in an upright position in use, and thus have a top 72 and a bottom 73. In this Figure, the columns 8 are shown having coupling members 71 both at the top 72 and at the bottom 73. This is to illustrate that the structural system 100 is suitable for raising a multi-storey building. Each floor slab 1 is connected at its plate-shaped member’s 2 corners 21 to respective complementary coupling members 71 . In the Figure, each coupling member 3 of the floor slab 1 is connected to two respective complementary coupling members 71 , namely the coupling member 71 arranged at the top 72 of a lowermost column 8 and the coupling member 71 arranged at the bottom 73 of an upper column 8 placed directly over, and concentric with the lowermost column 8. Fig. 5 shows another load-bearing component 7 of the system 100, namely a load-bearing shaft wall 9. Coupling members 71 complementary to the coupling members 3 of the floor slabs 1 , are provided at end portions 91 of a top face 92 and a bottom face 93, representing the top 72 and bottom 73, respectively, of the load-bearing shaft wall 9. When the load-bearing component 7 is a shaft wall 9, three square or rectangularly shaped floor slabs 1 can be connected to each complementary coupling member 71 of the shaft wall 9. Note that the load-bearing shaft wall 9 does not support the floor slab 1 other than at the coupling at the corners 21 .

[0100] In an alternative embodiment (not shown), the shaft wall may not be provided with complementary coupling members fastened thereto. Instead, a complementary coupling member 71 may be sandwiched between two shaft walls 9 which are arranged one on top of the other. The complementary coupling member 71 may in this case protrude from a joint between the shaft wall elements, and the coupling member 3 of the floor slab may be securely fastened thereto by means of for example bolts or screws. This solution is possible for shaft walls because they can withstand considerably larger buckling forces than the slim columns of this system. Further, the two shaft walls may typically be securely fastened to each other vertically by fastening means arranged at a distance from the complementary coupling member. Said fastening means may preferably be integrated in the shaft wall elements.

[0101] For load-bearing components 7 in the form of columns, two columns arranged on top of each other may be securely fastened to each other via the complementary coupling members 71 which also forms a sandwich connection with the floor slab’s coupling member 3. However, for shaft walls the connection between the shaft walls may be held separately from the connection between the shaft walls and the floor slabs. One effect of this feature is that the floor slabs may be removed or replaced without having to remove parts of the shaft wall.

[0102] The exploded view in Fig. 6 shows details of the connection between the coupling member 3 of the floor slab 1 and the two complementary coupling members 71 mentioned above, for Fig. 4. The complementary coupling members 71 of a column 8 can also be denoted flanges 71 . The connection is a sandwich-connection, where the floor slab’s 1 coupling member 3 is sandwiched between the two complementary coupling members 71 and further secured by fastening means 6. The fastening means 6 are here shown as bolts 61 and nuts 62. In a configuration where the floor slabs 1 are generally square or rectangular, one corner 21 each of up to four floor slabs 1 can be coupled between the same two complementary coupling members 71 , as illustrated by the central column 8 in Fig. 4.

[0103] When fewer than four floor slabs 1 are connected to a column 8, a supplementary coupling element 32 may be used to fill in the gap. This is illustrated in Fig. 6, where such a supplementary coupling element 32 is shown. The supplementary coupling element 32 completes the sandwich-connection to avoid or reduce uneven load-distribution in the connection.

[0104] Fig. 7 shows a coupling member 71 arranged on a column 8, and further provided with an ear 74 for connection to a further element of the system 100, such as a bracing member 12, like cross bracing by means of tension rods (as shown in Fig. 9), or a beam 13 (as shown in Fig. 10).

[0105] Fig. 8 shows another example of the supplementary element 32, for use where only one floor slab 1 coupling 3 is part of the sandwich-connection and a larger gap needs to be filled for achieving an even load distribution on in the connection.

[0106] In Figs. 9 and 10, two different load-bearing structural systems 100 are shown. Both systems 100 include a variety of different elements for the purpose of illustrating how a building can take form by using this principle of coupling the corners 21 of floor slabs 1 to load-bearing components 7 of different kinds and supplementing with other elements. The main difference between the two shown systems, is the way they are reinforced / stiffened. In the system in Fig. 9, cross bracing by means of bracing elements 12, such as tension rods, are used. The system in Fig. 10 is provided with shaft walls 9 which not only are load-bearing components 7 suitable to replace for instance two columns 8 each, but also provide an alternative to cross bracing.

[0107] The load-bearing structural system 100 of a building, is typically raised on and connected to a foundation 15 on a construction site. The important thing for the present system 100 is that it is indeed possible to arrange the upright load-bearing components 7 upright, i.e., vertically, and that, consequently, the floor slabs 1 in use, are arranged horizontally. In both Figs. 9 and 10, the foundation 15 is shown as a spread footing foundation 15, comprising a plurality of foundation units 151 each comprising a coupling 152, a pillar or foot 153 and a base 154. The coupling 152 is for connection and positioning of the loadbearing components 7 on the foundation 15. The coupling 152 is described in further detail below when discussing Fig. 14, and the foundation unit 151 is further discussed below for Fig. 15. The coupling 152 is further adapted for connecting to floor slab 1 couplings 3 and said coupling 152 has similar properties to the complementary coupling members 71 .

[0108] It must be noted that the spread footing foundation 15 is only one possible foundation for the system 100. Other examples include site-built concrete foundation, pillars, the roof of a parking garage, or similar. The important features of the foundation are in any case, that the foundation allows the system 100 to be installed with precision and to be properly anchored to the ground.

[0109] Both Figs. 9 and 10 show that the system 100 can be used for building a multi-storey building. In the drawings, a ground floor and a first floor are shown, as well as the floor of the second floor of the building. The uppermost layer of floor slabs 1 , may also be conceived as a roof. Clearly, in that case a roof slab may be provided which may not be of the same composition as the floor slabs 1 . Said roof slab may be provided with the same coupling member 3 for connecting to the load-bearing components 7, as disclosed herein for the floor slabs 1.

[0110] In Fig. 9 columns 8 are raised on foundation units 151 , and the floor slabs 1 of the ground floor are connected at their corners 21 in a sandwich connection between the complementary coupling 152 of the foundation unit 151 and a complementary coupling member 71 arranged at the bottom 73 of the column 8. Bracing members 12, shown as cross bracing using tension rods, are provided for stability and for distributing lateral loads to the columns 8. The bracing members 12 are typically arranged as shown, connecting the bottom 73 of one column 8 with the top 72 of a neighbouring column 8, and vice versa.

[0111] The embodiment of Fig. 10 shows the use of shaft walls 9. The shaft walls 9 provide the bracing effect that the tension rods do in the system of Fig. 9. In Fig. 10, the load-bearing shaft wall 9 is used for creating a shaft 10, in this case for stairs 16 or an elevator (not shown). A shaft may comprise of load-bearing shaft walls 9, and intermediate walls (not shown).

[0112] Fig. 11 shows, in a cross-sectional view, details the beam 13 and how it may be connected to floor slabs 1 and to columns 8 or other load-bearing, upright components 7. On the left, two floor slabs 1 are connected to a complementary coupling member 131 which is similar to the complementary coupling member 71 provided on the column 8 on the right in Fig. 1 1 . The connection on the column 8, to the right, also shows an ear 74 provided for connecting the beam 13 to the column 8. The purpose of the beam 13 in this system 100 is to make possible having a larger span, i.e., replacing a column 8 or another upright load-bearing component 7, and have the beam 13 direct the loads from the connected floor slabs 1 to the neighbouring columns 8 or other load-bearing components 7. One such other load-bearing component 7 is the shaft wall 9 shown in Fig. 10.

[0113] The coupling member 131 provided on the beam 13 replaces a “column connection” or connection to any upright load-bearing component 7. The coupling member 131 includes a disc or plate 132 provided with threaded bolt openings for securing the floor slab’s 1 brackets 3 to the plate 132 by means of bolts 61 . A central bolt 133 is provided in a central threaded opening in the plate 132 for adjusting the plate 132 vertically with respect to the beam 13.

[0114] Fig. 12 shows in an orthographic view from below, the “right side” -connection from Fig. 11 , i.e., the connection between the column 8, four floor slabs 1 and the end of the beam 13 coupled to the ear 74 on the column 8 for transferring loads to the column 8.

[0115] Fig. 13 shows an orthographic view from above of the “left side”-connection from Fig. 11 , i.e., the beam 13 supporting four floor slabs 1 . One of the floor slabs 1 is shown here with broken lines to properly make visible the connection. The beam 13 is provided with the complementary coupling member 131 which is similar to the complementary coupling member 71 provided on the other load-bearing components 7 of the structural system 100. The beam 13 may be an H-beam typically of a length corresponding to a length of two floor slabs 1 . The coupling member 131 is here shown fastened to four floor slabs 1 and resting on the beam 13.

[0116] Fig. 14 shows an example of the coupling 152 of the foundation unit 151 (Fig. 10) for connecting the system 100 to the foundation 15 on the construction site, and for adjusting the orientation of the load-bearing structural system 100. In this embodiment, the coupling 152 comprises a plate 156 to be levelled and anchored to the foot 153 (see Fig. 15). After levelling, by means of nuts 157, the plate 156 may be cemented to the foot 153.

[0117] Adjusting the orientation is important for making sure the upright load-bearing components 7 are arranged exactly vertically, and that the coupling members 71 for forming sandwich connections with the coupling members 3 of the floor slabs 1 , are oriented horizontally for providing the strongest possible connection, i.e., best possible load transfer. The coupling 152 is further provided with a “crown” comprising a steel ring 158 and threaded rods 159 screwed into the steel ring 158. The rods 159, here shown as eight rods 159, extend upwards, in use, and the coupling 152 is further provided with a top ring 160 which corresponds to the steel ring 158 and which is provided with holes 161 of the same number as the number of rods 159. A diameter of the holes 161 is larger than a diameter of the rods 159. The top ring 160 is securely fastened to the levelled plate 156 through a connection piece 162, so that each rod 159 of the steel ring 158 extends upwards through a corresponding hole 161 . The steel ring 158 with the rods 159 is movable horizontally, relative to the top ring 160 and thus allows for horizontal adjustment of the coupling 152 for providing easy connection with the lowermost layer of floor slabs 1 and any load-bearing component 7 raised on top of the foundation unit 151 .

[0118] Fig. 15 shows three floor slabs 1 connected to the foundation unit 151 and secured to the coupling 152. Instead of a fourth floor slab 1 , a mounting bracket 31 for mounting a balcony element (not shown) is fastened to the coupling 152. For legibility, the reference numbers for the details of the coupling 152 which are already shown in Fig. 13, will not be repeated for Fig. 15.

[0119] Note that the discussed foundation unit 151 is only one possible way of coupling the loadbearing structural system 100 to the foundation 15 at a construction site. The purpose of the disclosed embodiment of foundation unit 151 , is to show an example of how a horizontal connection point between the structural system 100 and the foundation 15 can be provided if the foundation is not already properly levelled. As already mentioned, many possible foundations may fit with this system.

[0120] Figs. 16a-16c show further possible variants mounting brackets 31 prepared for different amounts of “free space” at the coupling member 71, depending on how many floor slabs 1 which are already connected to the coupling member 71 . The mounting brackets 31 serve double purposes in that they have the same function as the supplementary coupling members 32 mentioned above for Figs. 6 and 8, and also serve as connections for further elements. The dimension, i.e., thickness h, of the mounting brackets 31 (and the supplementary coupling members 32) is the same as for the corner brackets 3 of the floor slabs 1 . The mounting brackets 31 may be provided with different additional elements such as an eye, a hook, a “pocket”, a slit or something else, which extends from the coupling member 71 and can be used for attaching facade elements such as a wall, a canopy, a roof structure, an advertising sign, a light fixture or the like. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims

C l a i m s1 . A floor slab (1 ) for a load-bearing structural system (100) of a building, the floor slab (1 ) comprising:- a load-bearing plate-shaped member (2) having at least three corners (21 ) and at least three side faces (22); and- a coupling member (3) arranged at each of the corners (21 ) for connecting each corner (21 ) to a load-bearing component (7) of the structural system (100), wherein the corners (21 ) are cut corners (21 ) each defining a corner face (23) connecting two adjoining side faces (22); wherein each coupling member (3) is fixedly connected to the load-bearing plate-shaped member (2) and protruding from the respective corner face (23), and wherein the coupling member (3) is adapted for being detachably connected to a complementary coupling member (71 ) of the load-bearing component (7) and for transferring load from the floor slab (1 ) to the load-bearing component (7).

2. The floor slab (1 ) according to claim 1 , wherein each coupling member (3) is fixedly connected within the load-bearing plate-shaped member (2).

3. The floor slab (1 ) according to claim 1 or 2, wherein the coupling member (3) extends within a coupling area (24) defined by the respective corner face (23) and an imaginary extension of the two respective side faces (22).

4. The floor slab (1 ) according to any one of the preceding claims, wherein the coupling member (3) is essentially flat and, in a position of use, protrudes horizontally from the corner face (23).

5. The floor slab (1 ) according to any one of the preceding claims, wherein the load-bearing plate-shaped member (2) is made of wood, composite material, clay material such as terracotta, or concrete, and further comprises reinforcement (5).

6. The floor slab (1 ) according to claim 5, wherein the coupling member (3) is arranged in connection with the reinforcement (5).

7. The floor slab (1) according to claim 6, wherein the reinforcement (5) comprises primary reinforcement (51) and secondary reinforcement (52) and the coupling member (3) is connected to the primary reinforcement (51 ).

8. The floor slab (1 ) according to any one of the preceding claims, wherein the floor slab (1) is prefabricated.

9. The floor slab (1 ) according to any one of claims 5-8, wherein the floor slab (1) is form-cast.

10. The floor slab (1 ) according to any one of the preceding claims, the coupling member (3) having a thickness (h) smaller than a thickness (H) of the plateshaped member (2) and protruding from a mid-plane of the plate-shaped member (2).

11. A load-bearing structural system (100) for a building, the load-bearing structural system (100) comprising:- a floor slab (1) according to any one of the preceding claims; and- a plurality of load-bearing components (7), each comprising at least one coupling member (71) complementary to the floor slab’s (1) coupling members (3), wherein the coupling member (3) of the floor slab (1 ) is adapted for being detachably connected to the complementary coupling member (71) of the load-bearing component (7) and for transferring load from the floor slab (1 ) to the load-bearing component (7).

12. The load-bearing structural system (100) according to claim 11 , further comprising fastening means (6) for detachably connecting each of the floor slab’s (1) coupling members (3) to a respective complementary coupling member (71).

13. The load-bearing structural system (100) according to claim 11 or 12, wherein the plurality of load-bearing components (7) includes a column (8) and / or a shaft wall (9).

14. The load-bearing structural system (100) according to any one of claims 11- 13, further comprising a plurality of floor slabs (1 ).

15. The load-bearing structural system (100) according to any one of claims 11 -14, wherein the complementary coupling member (71), in a position of use, protrudes horizontally from the respective load-bearing component (7).

16. The load-bearing structural system (100) according to any one of claims 11 -15, wherein the load-bearing components (7), when arranged in an upright position, have a top (72; 92) and a bottom (73; 93), and wherein both the top (72; 92) and the bottom (73; 93) are provided with a coupling member (71) complementary to the floor slab’s coupling member (3).

17. The load-bearing structural system (100) according to claim 16, wherein the floor slab’s coupling member (3) is arranged to be sandwiched between the top coupling member (71) of one load-bearing component (7) and the bottom coupling member (71 ) of a second load-bearing component (7) for erecting a multi-storey building.

18. The load-bearing structural system (100) according to any one of claims 11 -17, further comprising a supplementary coupling element (32) and / or a supplementary mounting bracket (31 ).

19. The load-bearing structural system (100) according to any one of claims 11 -18, further comprising a beam (13) for replacing a load-bearing component (7) and allowing a larger span.

20. The load-bearing structural system (100) according to any one of claims 11-19, further comprising a bracing member (12) such as tension rods for cross bracing.

21. The load-bearing structural system (100) according to any one of claims 11-20, further comprising a foundation unit (151) for positioning the load-bearing components (7) of the load-bearing structural system (100) on a foundation (15) at a building site.

22. A building comprising the load-bearing structural system (100) according to any one of claims 11-21 .

23. A method for assembly of the load-bearing structural system (100) according to any one of claims 11-21 , the method comprising the following steps:- providing a floor slab (1) according to any one of claims 1-10;- erecting first load-bearing components (7), each load-bearing component (7) comprising a top (72) end coupling member (71) complementary to the floor slab’s (1) coupling members (3); and - arranging the floor slab (1 ) so that each of the floor slab’s coupling members (3) overlaps a complementary fitting top (72) end coupling member (71 ) of one of the load-bearing components (7).

24. The method according to claim 23, further comprising the step:- erecting second load-bearing components (7) directly on top of the erected first load-bearing components (7) to form sandwich-connections wherein each of the floor slab’s coupling members (3) are sandwiched between two complementary coupling members (71 ).

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