EP2657423A1

EP2657423A1 - A concrete slab and a method of manufacturing a concrete slab, a building, and a method of mounting a concrete slab on a building structure

Info

Publication number: EP2657423A1
Application number: EP12165549.2A
Authority: EP
Inventors: Ronald Klein-Holte
Original assignee: VBI Ontwikkeling BV
Current assignee: VBI Ontwikkeling BV
Priority date: 2012-04-25
Filing date: 2012-04-25
Publication date: 2013-10-30
Anticipated expiration: 2032-04-25
Also published as: EP2657423B1

Abstract

A concrete slab (1) comprises a connecting portion (4) for connecting the concrete slab (1) to a building structure (2). The connecting portion (4) comprises a slab contact surface (5) for contacting a building structure contact surface (6) of a building structure (2) and a hooked reinforcing element (8) having a fixed portion (8a) and hook portion (8b). The fixed portion (8a) is embedded in the concrete of the concrete slab (1). At the hook portion (8b) the concrete slab (1) is provided with a recess (7) which opens to the outside of the concrete slab (1).

Description

The present invention pertains to a concrete slab.
Concrete slabs are widely known in the field of construction of buildings. Particularly, hollow core concrete slabs are manufactured in a factory; after curing, the slabs are transported to a construction site. Such slabs are typically used for making floors of a building. After erecting side walls the concrete slabs are placed on and supported by the side walls. Additionally, it is often desired to secure the concrete slabs to the side walls, which is possible by inserting and connecting reinforcing bars in the concrete slab and the wall. Remaining spaces around reinforcing bars may be filled with grout.
It is an object of the present invention to provide a concrete slab that can be fixed to a building structure in a manner which requires relatively little work at the construction site.
This is achieved with the concrete slab according to the invention, which comprises a connecting portion for connecting the concrete slab to a building structure, wherein the connecting portion comprises a slab contact surface for contacting a building structure contact surface of a building structure and a hooked reinforcing element having a fixed portion that is embedded in the concrete of the concrete slab and a hook portion where the concrete slab is provided with a recess which opens to the outside of the concrete slab.
Due to the presence of the recess, a reinforcing member of the building structure can be received therein. This means that in a mounted condition of the concrete slab and the building structure, the hook portion of the concrete slab and the reinforcing member of the building structure are disposed in a mutual position such that they can exert a force onto each other. This provides the opportunity to transfer a force via the reinforcing element instead of the concrete of the concrete slab only. The recess may open to the slab contact surface, but this is not essential.
The connecting portion may be provided at an end of the concrete slab. In practice a concrete slab is often block-shaped having opposite short side edges and opposite long side edges, whereas the small side edges mostly rest on vertical walls.
The hook portion may form a protrusion of the concrete slab. This means that the hook portion may be free from concrete.
The hook portion may extend parallel to the plane of the concrete slab. For example, the hook portion is curved with respect to the fixed portion within a plane. In a practical embodiment the hook portion is part of a U-shaped reinforcing element. The fixed portion may extend in longitudinal direction of the concrete slab whereas the hook portion extends transversely with respect to the longitudinal direction.
The recess may be partly surrounded by the hook portion. This does not necessarily mean that the hook portion forms a wall of the recess, since a layer of concrete may be present between the hook portion and the recess.
In a specific embodiment the hook portion protrudes laterally with respect to the longitudinal direction of the concrete slab. This provides the opportunity to secure the concrete slab to a neighbouring concrete slab having a similar protruding hook portion.
This embodiment may also comprise a second hooked reinforcing element which has a hook portion that protrudes at the opposite side of the concrete slab, whereas the second hooked reinforcing element is fixed to the hooked reinforcing element. In this case the concrete slab can be fixed to neighbouring concrete slabs at both sides.
The invention is also related to a building, comprising a building structure which is provided with a building structure reinforcing element, and a concrete slab which is provided with a hooked reinforcing element, wherein the building structure and the concrete slab are mounted to each other such that a hook portion of the hooked reinforcing element and at least a portion of the building structure reinforcing element lie in a plane parallel to the plane of the concrete slab. In other words, as seen in that plane, the hook portion and the building structure reinforcing element are located behind each other. This means that the hook portion and the reinforcing element can exert a force onto each other in a direction parallel to the plane of the concrete slab. It is advantageous that the force can be transferred via reinforcing elements instead of concrete only.
The invention is also related to a method of mounting a concrete slab as described hereinbefore on a building structure, wherein the building structure includes a protrusion projecting upwardly and a building structure contact surface directed upwardly, wherein the concrete slab is placed downwardly onto the building structure such that the protrusion is inserted into the recess until the slab contact surface of the connecting portion of the concrete slab rests on the building structure contact surface, wherein the hooked reinforcing element and the protrusion are adapted such that when the concrete slab rests on the building structure contact surface the hooked reinforcing element and at least a portion of the protrusion lie in a plane parallel to the plane of the concrete slab.
The invention is also related to a method of manufacturing a hollow core concrete slab, comprising the steps of preparing a mould in which channel recess elements are provided for obtaining channels in the concrete slab to be made and pouring concrete into the mould, wherein the steps of preparing the mould and pouring concrete are performed simultaneously whereas the mould is at least partly moved in a manufacturing direction, wherein at least a hooked reinforcing element is located within the mould at a predetermined location outside the channel recess elements, i.e. outside a path that the channel recess elements follow during manufacturing. Known production steps of preparing a mould and pouring concrete are formed by a slipformer or extruder. In case of an extruder the concrete is pressurized.
The hooked reinforcing element may have a U-shape of which the legs direct from an end portion towards the core of the intended slab.
The hooked reinforcing element may have a longitudinal portion extending in the manufacturing direction and a hook portion which extends transversely to the manufacturing direction.
After the step of pouring concrete the resulting product may be cut in transverse direction of the manufacturing direction at a predetermined location of cutting in order to make a separate slab thereof, whereas the longitudinal portion of the hooked reinforcing element extends beyond the hook portion thereof as seen from the location of cutting. In case of a U-shaped hooked reinforcing element the legs thereof will direct away from the location of cutting such that the hook portion is located at the location of cutting. Furthermore, the hooked reinforcing element may be provided with an extension which is directed to and ends at the intended location of cutting. The extension may be used to fix the hooked reinforcing element of the concrete slab to a building structure after finishing and/or cutting the concrete slab. The extension may be a threaded pin to which a bolt can be attached.
The hooked reinforcing element may be part of a lattice member, for example a cage-shape.
In the step of preparing the mould, a recess element can be placed at the hooked reinforcing element such that the hook portion and the recess element are aligned in the manufacturing direction. In case of the step of cutting the resulting product at the location of cutting, the recess element is located behind the hooked portion as seen from the location of cutting. The recess element may be an upright tube, for example. After finishing the concrete slab the recess element may be removed. Due to the presence of the recess element in the mould, a recess arises in the concrete slab as described in relation to several embodiments of concrete slabs hereinbefore.
The invention will hereafter be elucidated with reference to drawings showing embodiments of the invention very schematically.

Fig. 1 is a perspective view of a part of a building including an embodiment of a concrete slab according to the invention.
Fig. 2 is a similar view as Fig. 1, but showing the concrete slab in transparency and illustrating reinforcement bars that are embedded in the concrete slab.
Fig. 3 is a similar view as Fig. 2 of a part of the concrete slab on enlarged scale.
Fig. 4 is a similar view as Fig. 2, but showing an alternative embodiment including hook portions that protrude laterally of the concrete slab.
Fig. 5 is a similar view as Fig. 4, but showing two adjacent concrete slabs mounted on a supporting structure.
Fig. 6 is a similar view as Fig. 5, but showing an alternative embodiment.
Fig. 7 is an enlarged view of a part of Fig. 6.
Fig. 8 is a plan view of the embodiment of Fig. 6.
Fig. 9 is a side view of the embodiment of Fig. 6.
Fig. 10 is a similar view as Fig. 2 of an alternative embodiment.
Fig. 11 is a similar view as Fig. 2 of another alternative embodiment.
Fig. 12 is a similar view as Fig. 1 of still another alternative embodiment shown in transparency.
Fig. 13 is a side view of the embodiment of Fig. 12.
Fig. 14 is a plan view of the embodiment of Fig. 12.
Fig. 15 is a perspective view which illustrates an embodiment of a method of manufacturing a concrete slab according to the invention.
Fig. 16 is a cross-sectional view along the line A-A in Fig. 15 when the pouring device is at that location.
Fig. 17 is a similar view as Fig. 16, but showing a different lattice member.
Fig. 18 is a similar view as Fig. 16, but showing still another lattice member.

Fig. 1 shows a part of a building including an end portion of an embodiment of a concrete slab 1 according to the invention. An end of the concrete slab 1 is supported by a building structure, in this case a wall 2. Fig. 1 shows a condition in which the wall 2 and the concrete slab 1 extend transversely with respect to each other. The concrete slab 1 is of the type of a hollow core slab which is often used for making floors in buildings. The concrete slab 1 can have different sizes and shapes, but mostly it is block-shaped whereas the hollow channels extend parallel to its longitudinal centre line. The wall 2 may be made of concrete, as well.
The concrete slab 1 according to Fig. 1 has a staggered end portion where the thickness of the concrete slab 1 is thinner than an adjacent portion of the concrete slab 1 remote from the corresponding end of the concrete slab 1. The hollow channels of the embodiment as shown in Fig. 1 extend beyond the lowered end portion as seen from the corresponding end of the concrete slab 1 and extend above an upper face of the end portion.
Fig. 1 illustrates a manner of connecting the concrete slab 1 to the wall 2. The wall 2 is provided with one or more protrusions 3 that extend upwardly from the wall 2. In practice the protrusions 3 are reinforcing bars that are made of steel. The protrusions 3 may be integrated in the wall 2 upon manufacturing the wall 2 in a factory or mounted on the wall 2 at the construction site. The end portion of the concrete slab 1 of the embodiment of Fig. 1 forms a connecting portion 4 for connecting the concrete slab 1 to the wall 2. The connecting portion 4 comprises a slab contact surface 5 at its lower side, which contacts a wall contact surface 6 in the connected condition. Thus, the concrete slab 1 is vertically supported at the wall contact surface 6.
Fig. 1 shows that the protrusions 3 of the wall 2 extend through a through-hole 7 of the concrete slab 1. In order to mount the concrete slab 1 on the wall 2 easily, the through-hole 7 is broader than the total thickness of the protrusions 3 that extend through the through-hole 7. After installing the concrete slab 1 on the wall 2 the remaining space between the protrusions 3 and the surrounding wall of the through-hole 7 can be filled with grout. Due to this construction the concrete slab 1 is fixed with respect to the wall 2 in a direction parallel to the plane of the concrete slab 1.
Since concrete allows limited tension stress, the concrete slab 1 according to the invention is provided with a hooked reinforcing element 8. This is illustrated in the transparent views of Figs. 2 and 3, which show several reinforcing elements in the embodiment of Fig. 1. It can be seen that the hooked reinforcing element 8 comprises a U-shaped reinforcing bar 8 in the concrete slab 1. The reinforcing bar 8 comprises a fixed portion 8a which is embedded in the concrete of the concrete slab 1, and a hook portion 8b which partly surrounds the through-hole 7. The fixed portion 8a comprises two parallel linear bars in this case. In this embodiment the hook portion 8b is also embedded in the concrete of the concrete slab 1. A different shape of the hook portion 8b is conceivable. The function of the hook portion 8b is to transfer a force between the wall 2 and the concrete slab 1 in a direction parallel to the plane of the concrete slab 2 via the protrusions 3 and the reinforcing bar 8. The U-shape of the reinforcing bar 8 may also be formed by two separate bars having angled end portions, for example.
Instead of the through-hole 7 the concrete slab 1 may be provided with a recess at the hook portion 8b which opens at the side of the slab contact surface 5 only.
Figs. 2 and 3 also show auxiliary reinforcing bars 9 which extend transversely with respect to the longitudinal direction of the concrete slab 1. One of the auxiliary reinforcing bars 9 is fixed to the reinforcing bar 8. Hence, in this case the through-hole 7 is entirely surrounded by reinforcing bars: the hook portion 8b and a portion of one of the auxiliary reinforcing bars 9.
The auxiliary reinforcing bars 9 are also fixed to eight U-shaped longitudinal reinforcing elements 10 at the end portion of the concrete slab 1. Each longitudinal reinforcing element 10 extends within a plane that extends in longitudinal direction of the concrete slab 1 and transversely to the plane of the concrete slab 1. A function of the longitudinal reinforcing elements 10 is to reinforce the end portion of the concrete slab 1 against bending near the wall 2 where it is supported. It is noted that the hooked reinforcing element 8, the auxiliary reinforcing bars 9 and the longitudinal reinforcing elements 10 are part of a lattice member 20 which is embedded in the concrete of the concrete slab 1. The through-hole 7 is applied at a location where the lattice member forms a hook portion 8b. The concrete slab 1 may further comprise reinforcing bars, pipes, wires, prestressing tendons, or the like, at a lower portion of the slab 1 which extend along substantially the entire slab 1 in longitudinal direction thereof, like conventional hollow core concrete slabs. In Figs. 1-3 the presence of tendons are illustrated by a horizontal row of small circles near the bottom of the slab 1.
Referring to Fig. 1, the wall 2 and the concrete slab 1 form part of a building. Upon making the building, the concrete slab 1 is placed downwardly onto the wall 2 such that the protrusions 3 are inserted into the recess 7 until the slab contact surface 5 of the connecting portion 4 of the concrete slab 1 rests on the wall contact surface 6. In the embodiment as shown in Fig. 1 the protrusions 3 extend through the through-hole 7 beyond the hook portion 8b in upward direction. Alternatively, the hook portion 8b may be located such and the protrusions 3 may have a length such that when the concrete slab 1 rests on the wall contact surface 6, the hook portion 8b and end portions of the protrusions 3 lie in a plane parallel to the plane of the concrete slab 1. This provides the opportunity to transfer a horizontal force between the wall 2 and the concrete slab 1 via the hook portion 8b and the protrusions 3.
Fig. 4 shows an alternative embodiment of the concrete slab 1. The connecting portion 4 is provided with a protruding hook portion 8b. The hook portion 8b protrudes laterally with respect to the longitudinal direction of the concrete slab 1. Furthermore, the concrete slab 1 comprises a second hooked reinforcing element 8' which has a hook portion 8b'. The respective hook portions 8b and 8b' are located at opposite sides of the concrete slab 1. Both hook portions 8b, 8b' are fixed to common fixed portions, in this case parallel bars, that extend transversely through the concrete slab 1 and are embedded in the concrete.
Fig. 5 illustrates a situation where two concrete slabs 1 are installed next to each other. The slab contact surfaces 5 of the respective concrete slabs 1 rest on the wall 2. In this case the hook portions 8b, 8b' of the neighbouring concrete slabs 1 can be easily coupled to each other and to the protrusion 3 of the wall 2, as illustrated in Fig. 5. The protrusion 3 extends through the overlapping hook portions 8b, 8b' which together form a closed loop that surrounds the protrusion 3.
Figs. 6-9 show still another embodiment of a concrete slab 1. In this case two concrete slabs 1 have identical connecting portions 4 for connecting the concrete slabs 1 to the wall 2. Their slab contact surfaces 5 rest on the wall contact surface 6 of the wall 2 close to each other. Hence, both concrete slabs 1 are vertically supported at the wall contact surface 6. Figs. 8 and 9 clearly show that the protrusion 3 projects upwardly from the wall 2 between the opposite ends of the respective concrete slabs 1.
The structure according to Figs. 6-9 is further provided with a U-shaped link 11 of which the legs are received by the through-holes 7. Similar to the embodiment as shown in Figs. 2 and 3 each concrete slab 1 of Figs. 6-9 comprises eight parallel U-shaped longitudinal reinforcing elements 10 which are fixed to the auxiliary reinforcing bars 9. In this embodiment the U-shaped hooked reinforcing bar 8 of Figs. 2 and 3 is omitted. However, its function is accomplished by at least a part of the auxiliary reinforcing bars 9 and the longitudinal reinforcing elements 10, which is illustrated by broken lines in Figs. 7 and 8. Each of the formed virtual hooked reinforcing elements has a longitudinal portion that is directed from the end of the concrete slab towards its core and a hook portion that extends transversely to the longitudinal direction of the concrete slab 1. As seen from the end of the slab 1 the through-hole 7 is located beyond the hook portion 8b. After installing the concrete slabs 1 onto the wall 2 the space between the opposite concrete slabs 1 and between the legs of the U-shaped links 11 and the inner walls of the respective through-holes 7 can be filled with grout. Preferably, the link 11 and the protrusion 3 are fixed to each other by additional means, for example by means of welding.
Figs. 10-14 show alternative embodiments of the concrete slab 1 which is provided with reinforcing elements at end-portions thereof, but in which a through-hole or recess for receiving a reinforcing element of a supporting structure lacks.
Figs. 10 and 11 show U-shaped longitudinal reinforcing elements 12 which are embedded in the concrete slabs 1. In the embodiment of Fig. 10 the three U-shaped longitudinal reinforcing elements 12 are fixed together by the auxiliary reinforcing bar 9. The reinforcing elements 12 extend within a plane which is substantially parallel to the plane of the concrete slab 1. The embodiment of Fig. 11 comprises two U-shaped longitudinal reinforcing elements 12. Each of the latter elements 12 extends within a plane substantially perpendicularly to the plane of the concrete slab 1. A function of the U-shaped longitudinal reinforcing elements 12 is to improve the bending stiffness of the end portion of the concrete slab 1 when it is supported there by a supporting structure.
The embodiment of Fig. 11 is also provided with extensions, or in this case threaded ends 13, which are fixed to the respective U-shaped longitudinal reinforcing elements 12. The threaded ends 13 can be used for attaching the concrete slab 1 to a supporting structure. This is illustrated in Figs. 12-14, which show how the concrete slab 1 of Fig. 11 is fixed to the wall 2. A profile 14 which has a Z-shaped cross-section is attached to the concrete slab 1 by means of the threaded ends 13. Fig. 13 shows that a horizontally-oriented lower portion of the profile 14 supports the concrete slab 1, whereas a horizontally-oriented upper portion of the profile 14 is supported by the wall 2. Furthermore, the upper portion of the profile 14 comprises a through-hole 15 through which the protrusion 3 of the wall 2 extends. In mounted condition a horizontal force on the concrete slab 1 is transferred to the wall 2 via the U-shaped longitudinal reinforcing elements 12, the threaded ends 13, the profile 14 and the protrusion 3. It is noted that the threaded ends 13 may be replaced by pins, bars or the like, without thread.
The embodiments of the hollow core concrete slab 1 as described hereinbefore can be made by a method of manufacturing according to the present invention. Conventional hollow core concrete slabs are usually manufactured in great length, for example 150 m, and cut afterwards in shorter elements of for example 5 m, but shorter or longer elements are conceivable. Fig. 15 shows an embodiment of an apparatus 16 for manufacturing a hollow core concrete slab 1 according to the invention. The apparatus 16 comprises a pouring device 17 which can be moved by means of wheels over a work floor 18 in a manufacturing direction X.
Fig. 16 shows a cross-section of the apparatus 16 according to Fig. 15 in case when the pouring device 17 is at the location indicated by A-A.
On the work floor 18 two upright opposite mould parts 22 are located at a predefined distance from each other, between which concrete can be poured. The inner contours of the mould parts 22 define the shapes of sidewalls of the resulting concrete slab 1. Both upright mould parts 22 and the work floor 18 form part of a mould.
The pouring device 17 is provided with channel recess elements 23 for obtaining the hollow channels in the hollow core concrete slab 1 to be made. The channel recess elements 23 are elongated bodies that are fixed to the pouring device 17. The length of a channel recess element 23 may be 1 m, for example, but a longer or shorter channel recess element 23 is conceivable. During the manufacturing process the pouring device 17 including the channel recess elements 23 move continuously forward and concrete is supplied to the mould simultaneously. As a consequence, at the rear side of the pouring device 17 the intended slab appears, which is shown at the right side of Fig. 15. In an alternative embodiment the mould parts 22 may be attached to the pouring device 17, as well. This is typically the case when using a slipformer. In another embodiment the apparatus 16 may comprise an extruder. In that case the channel recess elements 23 may be part of a plate-shaped mould through which the concrete is pressed during displacement of the apparatus 16, hence forming the concrete slab 1.
Due to the continuous manufacturing process the channel recess elements 23 are removed from the resulting slab after the step of pouring concrete. It is noted that the process is illustrated and described in a simplified way, but in practice it may be a more complicated multi-step process. The apparatus 16 may be provided with compacting members (not shown) for compacting the concrete. The compacting members may comprise vibrating elements so as to fluidize the concrete.
Reinforcement wires 19, tubes, prestressing tendons, or the like, may lay on the work floor 18 before the pouring device including the channel recess elements 23 passes. The wires 19 may be taken up by the pouring device 17 in a known manner such that they have a desired location within the mould when concrete is poured into the mould.
Fig. 15 shows that at different location along the work floor 18 the lattice members 20 are placed on the work floor 18. After the pouring device 17 has passed the lattice members 20 they are embedded in the concrete and several concrete slabs 1 can be made by cutting the resulting product on the work floor 18. An intended location of cutting is indicated by reference numeral 21 in Fig. 15. This means that the resulting slabs 1 at both sides of the location of cutting 21 will have an end portion that is provided with the lattice member 20, such as shown in Figs. 2, 3, 6-9, 12, 13. Within the lattice member 20 a recess element can be placed before pouring concrete in order to create a recess or through-hole 7 in the intended slab 1. The staggered end portions of the slabs can be created by removing concrete, which has not fully cured yet, locally.
The lattice member 20 can have numerous shapes and dimensions. For example, it may have a cage shape and comprise U-shaped reinforcing elements of which the legs direct from the end portion of the concrete slab 1 towards the core of the slab 1.
It is noted that the lattice member 20 is located outside the channel recess elements 23. In the embodiment of Fig. 16 the lattice member 20 is located below the channel recess elements 23. Before starting pouring of concrete the lattice member 20 may be placed onto the work floor 18 directly or by means of supporting elements (not shown).
The embodiment of the concrete slab 1 according to Fig. 4 can also be made by means of the method according to the invention. This is illustrated in Fig. 17. In the step of preparing the mould the hook portions 8b and 8b' extend above the upright mould parts 22.
Alternatively, in the step of pouring the concrete is poured such that at least a part of the hook portions 8b and 8b' extend above the upper surface of the resulting concrete slab 1. At the construction site the hook portions 8b and 8b' can be deformed to a horizontal position before installing the concrete slab 1.
Fig. 18 shows still another embodiment of the lattice member 20. In this case the lattice member 20 comprises vertical bushes 24 at its opposite side ends. The bushes 24 are provided with internal threads and are located just below horizontal portions of the upright mould parts 22. As a consequence, after manufacturing a slab 1 including the lattice member 20 according to Fig. 18 bolts can be fixed to the bushes 24. When installing two slabs 1 next to each other they can be fixed to each other via a common link, for example a steel plate, which is fixed by bolts to respective bushes 24 of adjacent slabs 1.
From the foregoing it will be clear that the concrete slab according to the invention can be easily and reliably fixed to a building structure such as a wall, whereas the concrete slabs can be manufactured in a simple manner by means of the method according to the invention.
The invention is not limited to the embodiments as shown in the drawings and described hereinbefore, which may be varied in different manners within the scope of the claims. For example, it is conceivable that the building structure is a different structure than a vertical wall.

Claims

A concrete slab (1), comprising a connecting portion (4) for connecting the concrete slab (1) to a building structure (2), wherein the connecting portion (4) comprises a slab contact surface (5) for contacting a building structure contact surface (6) of a building structure (2) and a hooked reinforcing element (8) having a fixed portion (8a) that is embedded in the concrete of the concrete slab (1) and a hook portion (8b) where the concrete slab (1) is provided with a recess (7) which opens to the outside of the concrete slab (1).
A concrete slab (1) according to claim 1, wherein the connecting portion (4) is provided at an end of the concrete slab (1).
A concrete slab (1) according to claim 1 or 2, wherein the hook portion (8b) forms a protrusion of the concrete slab (1).
A concrete slab (1) according to one of the preceding claims, wherein the hook portion (8b) extends parallel to the plane of the concrete slab (1).
A concrete slab (1) according to one of the preceding claims, wherein the hook portion (8b) is part of a U-shaped reinforcing element (8).
A concrete slab (1) according to one of the preceding claims, wherein the recess (7) is at least partly surrounded by the hook portion (8b).
A concrete slab (1) according to one of the preceding claims, wherein the recess is a through-hole (7).
A concrete slab (1) according to claim 3, wherein the hook portion (8b) protrudes laterally with respect to the longitudinal direction of the concrete slab (1).
A concrete slab (1) according to claim 8, wherein the concrete slab (1) comprises a second hooked reinforcing element (8') having a hook portion (8b') which protrudes at the opposite side of the concrete slab (1), whereas the second hooked reinforcing element (8') is fixed to the hooked reinforcing element (8).
A concrete slab (1) according to one of the preceding claims, wherein the concrete slab (1) is a hollow core concrete slab.
A building, comprising a building structure (2) which is provided with a building structure reinforcing element (3), a concrete slab (1) which is provided with a hooked reinforcing element (8), wherein the building structure (2) and the concrete slab (1) are mounted to each other such that a hook portion (8b) of the hooked reinforcing element (8) and at least a portion of the building structure reinforcing element (3) lie in a plane parallel to the plane of the concrete slab.
A method of mounting a concrete slab (1) according to one of the claims 1 - 10 on a building structure (2), wherein the building structure (2) includes a protrusion (3) projecting upwardly and a building structure contact surface (6) directed upwardly, wherein the concrete slab (1) is placed downwardly onto the building structure (2) such that the protrusions (3) are inserted into the recess (7) until the slab contact surface (5) of the connecting portion (4) of the concrete slab (1) rests on the building structure contact surface, wherein the hooked reinforcing element (8) and the protrusion (3) are adapted such that when the concrete slab (1) rests on the building structure contact surface (6) the hooked reinforcing element (8) and at least a portion of the protrusion (3) lie in a plane parallel to the plane of the concrete slab (1).
A method of manufacturing a hollow core concrete slab (1), comprising the steps of preparing a mould in which channel recess elements are provided for obtaining channels in the concrete slab (1) to be made and pouring concrete into the mould, wherein the steps of preparing the mould and pouring concrete are performed simultaneously whereas the mould is at least partly moved in a manufacturing direction (X), wherein at least a hooked reinforcing element (8) is located within the mould at a predetermined location outside the channel recess elements.
A method according to claim 13, wherein the hooked reinforcing element has a longitudinal portion (8a) extending in the manufacturing direction and a hook portion (8b) which is directed transversely to the manufacturing direction, and wherein after the step of pouring concrete the resulting product is cut in transverse direction of the manufacturing direction (X) at a predetermined location of cutting (21) in order to make separate slabs thereof, whereas the longitudinal portion (8a) of the hooked reinforcing element (8) extends beyond the hook portion (8b) thereof as seen from the location of cutting (21).
A method according to claim 14, wherein the hooked reinforcing element is part of a lattice member (20).