WO2011155842A1

WO2011155842A1 - Floor, comprising prefab elements with pockets and easy access means to and from said pockets

Info

Publication number: WO2011155842A1
Application number: PCT/NL2011/050421
Authority: WO
Inventors: Gerardus Cornelis Maria Van Der Zanden
Original assignee: Infra+ B.V.
Priority date: 2010-06-09
Filing date: 2011-06-09
Publication date: 2011-12-15
Also published as: EP2580404B1; EP2580404A1; NL2004861C2

Abstract

Floor system, comprising a series of concrete prefab elements, which prefab elements comprise a series of longitudinal beams at an upper side, on a slab, and at least two cross beams, cover elements carried on said beams, wherein a pocket is provided between two adjacent beams, the cross beams and a cover element, at least some of the prefab elements comprising entry and/or exit elements for access into and/or from the pockets through at least one of the cover element and a cross beam.

Description

Title: Floor, comprising prefab elements with pockets and easy access means to and from said pockets.

The invention relates to a floor system, comprising a series of concrete prefab elements. The invention especially relates to a floor system having spaces extending below cover elements, suitable for utility lines such as drainage, mains or such pipes, electrical or data lines, telephone lines and the same.

For building buildings it is known to use concrete prefab elements, for example for floors and walls. For prefab floor elements it is known to us elements comprising channels extending in a longitudinal direction through the element, for feeding utility lines and pipes through the floor. These elements are closed on both an upper and lower side. Holes are drilled through the top or bottom surface, into a channel, for leading the lines out of the channel towards a space below or above the element.

It is further known to use such elements having a slab and a number of parallel beams at the lower side thereof, the slab forming the floor of a space above. Utility lines can be placed between the beams, below the slab. Again, openings can be drilled or otherwise formed for leading the utility lines into the space above. From between the beams the utility lines can easily be fed into adjacent walls. After hanging the lines between the beams, a ceiling can be mounted to the lower side of the beams.

From WO2009/104951 it is known to use prefab floor elements which have beams on an upper side of a slab. The slab can form the ceiling of a space below, whereas between the beams above the slab pockets are provided for the utility lines. Openings are provided through the beams, for feeding the lines in a direction perpendicular to the longitudinal direction of the beams, from one pocket to the next. At the longitudinal ends of the slab cross beams are provided, between adjacent longitudinal beams, closing off the pockets at said ends. A cover element is placed over the beams and slab, closing off the pockets at the top and forming a floor. These elements have the advantage that the utility lines can be placed from the top side, the space below the floor being ready for finishing. The cross beams provide added strength and make mounting and finishing more easy.

A disadvantage of these elements can be that the utility lines cannot easily be brought into or lead out of the pockets. Access to the pockets has to be gained through the cover elements, through the slab or through the cross beams. This is cumbersome and time consuming, Moreover, when the floor elements are placed access to the pockets may be even more restricted by walls placed below and above the cross beams.

WO02/35029 discloses a floor system comprising a series of parallel metal I-beams supported by a support structure. Between two adjacent I- beams tubes are provided, supported on the lower flanges of the beams. Sheet like elements are carried on the upper sides of the tubes and on the upper flanges of the I-beams, forming a floor. In the floor connecting boxes are supported, which are closed at the upper side by a lid. Plug sockets are provided in the boxes. Additionally air outlet openings are provided in the floor. In order to provide any utility lines in the floor system, such as lines to be connected to the boxes or air outlets, the sheet like elements have to be removed.

There is a need for an alternative floor system. Moreover there is a need for concrete prefab floor elements for a floor system, allowing easier installing of utility provisions, especially lines and pipes.

In a first aspect a floor system according to the present disclosure can be characterised by a series of concrete prefab elements, which prefab elements comprise a series of longitudinal beams, such as substantially parallel beams, at an upper side, on a slab, and at least two cross beams, cover elements carried on said beams. A pocket is provided between two adjacent beams, the cross beams and a cover element. At least some of the prefab elements can comprise entry and/or exit elements for access into and/or from the pockets through at least one of the cover element and a cross beam.

In another aspect a prefab floor element can comprise a series of substantially parallel beams at an upper side, on a slab, and at least two cross beams, cover elements carried on said beams. A pocket is provided between two adjacent beams, the cross beams and a cover element. The prefab element comprises entry and/or exit elements for access into and/or from the pockets through at least one of the cover element and a cross beam.

In another aspect a method according to the description can be characterised in that a concrete prefab floor element as described before is placed on at least to carrier elements, such as walls or pillars near opposite longitudinal ends. Utility lines or pipes can be placed in or through the pockets between adjacent beams, in longitudinal and/or cross direction of the element, with an end of the line or pipe below a top surface of the beams. A cover element is placed over the pocket, with an opening over said end. A utility pipe or line is connected through the opening to said end, where after the opening is closed around the utility pipe or line extending through said opening.

In order to further elucidate the invention embodiments of a floor system, floor elements, method and building shall be described hereafter, with reference to the drawings. Therein shows:

Fig. 1 in top view a floor according to the description, with partly removed cover elements;

Fig. 2 in perspective view a prefab floor element;

Fig. 2A in cross section part of a floor element of fig. 1, comprising part of the slab, two beams and part of a covering element, and schematically an adjoining floor element;

Fig. 2B in cross section part of a floor element of fig. 1, comprising part of the slab and a beam, in an alternative embodiment;

Fig. 2C in cross sectional view a cross beam and slab part, with a filler element along part of the cross beam; Fig. 2D and E alternative embodiments of a beam with cover elements;

Fig. 2F in cross sectional view a cross beam and slab part, with a filler element extending through part of the cross beam and the slab;

Fig. 3 in sectional view along the line III - III in fig. 1 a floor, with access means; and

Fig. 4 schematically a cross section of a floor along the line IV - IV in fig. i;

Fig. 5A - C schematically as series of end elements, in top view, side view and cross sections;

Fig. 6 schematically in side view part of a wall and two floor elements, along the line VI - VI in fig. 7; and

Fig. 7 in top view schematically part of an element, without a wall part above the element and the top floor element removed.

In this description embodiments are shown of a floor system, elements, methods and a building by way of example only. These should by no means be considered as limiting the scope of protection sought, as defined in the claims. In the description the same or similar elements have the same or similar reference signs. In the description a floor system is described

separating a lower floor space from an upper floor space. A lower side of the elements therefore can be or can be prepared as a ceiling of the lower floor. However, the floor or floor system can also be used for other floors or ceilings, for example but not limited to above crawling spaces, for cellars or for roofs.

In this description utility pipe or line or similar wording has to be understood as including at least any utilitarian provision needing pipes, hoses, cables, drains or the like provisions for transporting for example water, sewage, electricity or data.

In fig. 1 a floor 100, also referred to as floor system 100 is shown in top view, comprising a series of concrete prefab floor elements 1. These floor elements 1, which can for example be according to fig. 2, are supported on support elements 26, such as a wall or pillar, at or near longitudinal ends 6, preferably by cross beams 7, enclosed within the wall 26. As can be seen in fig. 1 the elements 1 are interconnected by interconnecting elements 8, as shall be discussed here after, and can span the entire width WB of a relevant part of a building 101, for example but not limited to a span of 5 metres or more.

In the embodiment shown the floor 100 has a length Lb, defined by the combined widths W, WA of the elements 1, 1A, IB, whereas the floor has a width WB, defined by the length L of the elements 1, 1A, IB.

In fig. 2 a floor element 1 is shown, comprising a slab 2, four parallel beams 3 extending in a length direction LI on a top side 4 of the slab 2. The slab 2 is in this example substantially square, having a length L and a width W. A first beam 3A and a second beam 3B extend along longitudinal sides 5A, 5B of the slab 2. On opposite ends 6A, 6B of the slab 2 two cross beams 7 A, 7B are provided, between the ends of the beams 3A, B, connecting these beams 3A, B. The third longitudinal beams 3C extends in between the first and second beam 3A, 3B and are connected at opposite ends to the cross beams 7 A, B. A series of first openings 8 is provided in the first and second longitudinal beams 3A, B, such that two elements 1 can be placed side by side and be connected to each other by connecting means (not shown) extending through said openings 8, for example but not limited to nuts and bolts, screws, chemical anchors, rivets and the like known connecting means. A second series of openings 9 can be provided, extending through the first, second and third longitudinal beams 3A, B, C, wherein preferably openings 9 in adjacent beams 3 are in line with each other, such that long elements (not shown) such as but not limited to pipes, hoses, lines and the like can easily be fed through said openings 9, in a direction substantially cross to the longitudinal direction LI of the beams 3. The openings 9 can be larger than the openings 8. The openings 9 can have a lower side substantially flush with the top side 4 of the slab 2. The cross beams 7 are preferably without openings 8 or 9. In fig. 2A in cross section part of an element 1 is shown, showing a beam 3, especially an outer first or second beam 3A, B, and the slab 2, with a side 5 of the slab 2. As can be seen the openings 8 and 9 can extend

substantially parallel to each other across the beam 3. The beam 3 has a height H above the top side 4 of the slab 2. The slab 2 has a thickness t between the top side 4 and the opposite lower or bottom side 10. The bottom side 10 can during use for example form a ceiling of a space SB below the floor element 1 or of a crawl space. The beam 3 has, in this example, a substantially flat top side 11 and two opposite side surfaces 12, 13, which slope at an angle γ relative to the top surface 4 of the slab 2. In the embodiments shown the top surface 4 of the slab 2 extends, during use, substantially horizontally, meaning that in these embodiments the top surface can for practical purposes be referred to as a horizontal surface. Obviously an element 1 could be positioned at an angle, having the surface 4 sloping in one or two directions. In the embodiment shown the angle γ can be the same for both or all sloping surfaces 12, 13 of the same or all beams 3. In the embodiment shown the edge 5 of the slab 2 is defined substantially by a substantially straight, flat side surface 14, extending substantially perpendicular to the top surface 4. The sloping surface 12 of the beam is connected to the sloping side surface 12 of the beam, in this embodiment directly, that is without an intervening part of the top surface or beam. In fig. 1A in dotted lines a second element 1A is shown, the side surface 14 thereof positioned against the side surface 14 of the element 1. A stripe- dotted line 15 shows schematically a connecting element extending through openings 8 in line with each other for connecting the elements 1, 1A. As can be seen in fig. 1 the beam 3 can have a substantially trapezoid cross section, wherein the top surface 11 has a width Wl and the base, near the top surface 4 of the slab 2 has a width W2. As can be seen in fig. 1A the longitudinal outer beams 3A, B can have a cross sectional area Al which is smaller than the corresponding cross sectional area A2 of the beam or beams 3C in between. The area's Al, A2 can be chosen such that when two outer beams 3 of two adjacent elements 1, 1A are properly connected by the connecting means 15, the load capacity of two joined beams 3A, B of such elements 1, 1A is about the same as the load capacity of the or any of the intermediate beams 3C. This can for example be achieved by the widths Wl, W2 of the outer beams 3A, B being about half the widths Wl, W2 of the or any intermediate beam(s) 3C.

Between the beams 3 above the top surface 4 of the slab 2 pockets 16 are provided, in which utility lines such as water mains, gas, electricity, data and the like can be positioned, fed through the openings 9 and/or the slab 2 and/or a cover element 17 and/or in any other suitable way. A top floor element or elements 17 can be placed on the top surfaces 11 of the beams, for forming a floor 18 and for closing off the pockets 16. Openings 19 can be provided in the top floor elements 17 for feeding utility lines into or from the pockets 16 from or to a space 20 above the floor 18. Similarly openings 21 can be provided in the slab 2 for feeding utility lines into or from the pockets 16 from or to a space SB below the slab 2. Isolating material 23, especially but not limited to acoustically isolating elements such as rubber, elastomeric, plastic and/or foam strips can be placed between the beams 3, 7 and the top floor elements 17.

In fig. 2B a partial cross section of an element 1 is shown, in an alternative embodiment, in which a beam 3C is shown on the slab 2. The beam 3C has a stepped top surface 11, such that on two opposite, longitudinal sides a shoulder 24 is formed on which an edge of the top floor element 17 can be placed. This will allow a smaller overall height Ht of the element 1 with top floor elements 17, whereas about the same load capacity can be obtained with similar width beams 3 as in an embodiment of fig. 2A. In this embodiment a series of top floor elements 17 is provided, allowing access to individual pockets 16 more easily. Isolating elements 23 are provided between top floor elements 17 and shoulders 24. Similarly longitudinal first and second beams 3A, B and cross beams 7 A, B could be provided with a stepped upper surface 11, at the side facing the adjacent pocket 16, as schematically indicated in fig. 2B by the vertical line 14A. Fig. 2C shows part of an element 1, showing a cross beam 7 and slab 2. At the top of the beam 7, at a side facing the pocket 16 an edge portion 26 is made of a material different from the concrete from which the slab and beams are formed. The material of the edge portion 26 can for example be softer and/or more brittle than the concrete. During use a wall element 27, for example but not limited to a prefab concrete element or a brick wall, can be placed on top of the top surface 11 of the cross beam 7, as for example schematically shown in fig. 2C in broken lines. The edge portion 26 allows easy access into said wall element 27, easier than when part of the concrete of the beam has to be removed, for example for cables or pipes, as schematically indicated by striped line 22. Obviously the same way different parts of for example an edge of a beam 3, 7 or a slab 2 can be made of the same or similar material, for the same or similar purpose. Openings such as 8, 9, 19, 21 can also be made by providing such material in a position in which an opening could be advantageous, such that during use the opening can easily be created by removing part or all of said material.

In the embodiment of fig. 2D the cover elements 17 are provided with stepped side edges too, such that these edges are close to each other at a top level, an isolating strip 23 being provided in between, whereas at a lower level the edges are carried by the shoulders 24, again with intermediate isolating elements such as strips 23. This reduces again the risk of contact noise, even further than the embodiment of fig. 2B since all of the top surface 11 of the beams 3 is covered by the cover elements 17 and isolating material 23, whereas the building height Ht is still reduced with respect to the embodiment of fig. 2A.

In fig. 2E a further alternative embodiment is shown, in which the cover elements 17 are provided with interacting side edges 17A. In this embodiment by way of example the side edges 17A are provided with complementary hook shapes, such that they are preventing from shifting relative to each other in a substantially horizontal direction. Obviously in a similar manner the upper surface 11 of the beams 3 could be provided with similar profiles for preventing the cover elements 17 from shifting.

Fig. 2F schematically shows a partial cross section of an

embodiment, comparable to that of for example fig. 2C, wherein a portion 26 of a cross beam 7 and the slab 2 is made of a material different from the concrete from which the slab and beams are formed. The material of the edge portion 26 can for example be softer and/or more brittle than the concrete, for the purpose as described with reference to fig. 2C. In this embodiment utility lines 22 can be fed from the spaces or pockets 16 into the wall 27 above and/or below the element 1 and vice versa as well as through the wall from below the element 1 to above the element 1 and vice versa.

An element 1 can be made of concrete, preferably compacted concrete. In advantageous embodiments the element 1 can be made of self compacting concrete, foaming concrete or the like. Self compacting concrete will easily allow forming the element in a substantially closed mould cavity.

In fig. 1 a first element 1 is shown near for example a middle position of the length LB of the floor 100. Said first element 1 can have an opening 30 for accommodating for example but not limited to stairs 104 or an elevator, or for forming a vide in the floor 100. This element 1 has two outer longitudinal beams 3A, B, and three cross beams 7, of which a middle one 7B extends between the outer longitudinal beams 3A, B spaced apart from the first and third cross beams 7 A, C near the opposite longitudinal ends 6 of the element 1. Intermediate beams 3C extend between the second and first cross beams 7 A, 7B. The opening 30 is therefore formed between the longitudinal beams 5A, B, and the first and second cross beams 7A, B. An extension 31 of the slab 2 and a further beam 7D can be provided within the opening 30, to amend the shape and dimensions thereof, based on an elevator or stairs 104 that has to be mounted within said opening 30.

At at least one end 103 of the floor 100 an end element 1A is provided. The elements 1 can have a width W, whereas the end element 1A can have a width WA, which can be smaller than the width W, to fit in the remaining space between an element 1 and the adjacent end 103 of the floor. The end element 1A can have basically the same construction and

configuration as the elements 1, except for the width WA and the number of beams 3. In the embodiment shown in fig. 1 the end element 1A has two longitudinal end beams 3A, B, as do the other elements 1, but has only one intermediate longitudinal beam 3C. In the embodiment shown the distance Dl between the first longitudinal beam 3A and the adjacent intermediate beam 3C is the same as the corresponding distance Dl in the adjacent element 1, whereas the distance D2 between the intermediate longitudinal beam 3C and the other longitudinal outer beam 3B is smaller. The outer beam 3B can be placed on or in an end wall 27A of the building 101, or at least on or in an inner part of such wall 27A, as also shown in fig. 4. Openings 9 can also be provided in the longitudinal second outer beam 3B in said wall 27A, such that pipes or lines 33, in fig. 1 shown as a drain or sewage pipe, can be fed in relatively large lengths through said openings 9 in the beams 3A, B, C of the end element 1A and similar openings 9 in the adjacent elements 1 of the floor 100, towards a pocket 16 in which a connection has to be made to a utility element, such as but not limited to a basin, bath, toilet, bidet, tap etcetera. Feeding long lengths of pipes prevents that in the work many connections have to be made. For reason of clarity the openings 8 are not shown in fig. 1. As is shown in fig. 4 the outer beam 3B of element 1A can be placed on or in an inner part 33A of a wall 27A, after which pipes or the like can be fed through opening 9. Then the outer part 33B of the wall 27A can be placed, shielding the beam 3B and openings 9 from the environment. In an embodiment the openings 9, especially in the outer beams 3A, 3B can be blocked by easily removable elements or parts, such as but not limited to elements made of foam, wood or plastic, which can be pierced or removed for feeding a pipe or line or such element into the pockets 16, whereas the openings can be closed afterwards, if so desired. As is shown in fig. 3 the pipe 33 can have or can be provided with a connector 35 at an end 34 within the pocket 16, such as a glue or weld fitting. Similarly a line could be provided with a connector. The connector 35 is provided such that a side 36 thereof facing upward lies below the lower side 37 of the cover element 17. In the cover element 17 an opening 19 is provided through which a connecting tube, pipe or line or such connecting element 38 can be led, to be connected to said connector 35. The opening has a cross section D3 which is relatively large, compared to the cross section of diameter of the element 38 to be led there through. In an embodiment the cross section D3 can be at least 1,5 times the largest diameter of the element 38, measured on the outside of the element 38. The opening is preferably big enough for a labourer to enter his hands through for fitting the element 38 properly in the connector 35. Afterwards the space between the edge of the opening 19 and the element 38 can be closed, for example by concrete. In an embodiment a ring 39 can be fitted over the element 38, for example prior to connecting the element to the connector 35, which ring can be slid over the element into the space 40 and can be fixed therein, if so desired, for example by glue, mortar, concrete or any other suitable means. In an embodiment the ring 39 can be made in two semi circular ring parts to be fitted around the element 38 and into the space 40. Since the connector 35 extends entirely below the upper side of the beams 3A, 3B, 3C, the pipes and connectors can be fitted easily, for example even prior to placing the floor elements 1 or at least prior to placing the cover element 17, without running the risk of damaging them when placing he cover elements 17. Moreover, since they do not extend above the floor 100 during work in progress the risk of damage by for example people or materials passing over the floor is also minimised. By using one or more relatively large openings 19 in the cover element 17 the pockets 16 can be used in a way similar to crawl spaces below a lower floor. The opening 19 can for example be round or rectangular, and can be closed by a hatch, lid or other suitable closure means for temporarily or permanently closing off said opening, partly or in its entirety.

In embodiments a utility unit, such as a sanitary object, for example a bath, toilet, sink, or a wall or wall section can be placed on or above the cover element and, preferably, above or overt the opening 19 in the cover element 17, especially permanently, into which a utility line extending through the opening 19 can extend. The opening and, especially, the enlarged opening and cover 39 allow easy access and mounting of the utility line during construction.

In fig. 3 at the right hand side a further line 40 is shown, for example an electricity or data line, a phone line or a mains, from the pocket 16 into the wall 27 or vice versa. As can be seen an element of a material 26 is provided in the cross beam 7C, extending in an edge portion thereof, for easy access through said cross beam. The material of the element 26 can be softer or more brittle than the concrete of the beam 7, such that it can be broken away or otherwise traversed more easily than the beam. The material can in an embodiment for example be plastic, brick, mortar, sandstone, or even foam, cardboard or wood or any other appropriate material. Similarly some or all of the openings 9 can be closed off initially with such material. Especially the openings 9 in the beams 3A, B, more specifically in the beams 3B which are to be embedded in or against walls 27A at the ends 13 of the floor. In

embodiments the openings 9 can be formed by placing blocks of such material, such as but not limited to foam or stone, inside a mould, after which the concrete can be poured into the mould around the blocks. When feeding lines through the elements the blocks can then be broken away from said openings 9 in appropriate openings 9. Such may prevent even better exchange of for example sound, heat or cold, moisture, air or other elements between the pockets.

Similar to the openings 19 can openings 20 be provided in the slab 2, as discussed before, in a manner for example similar to the openings 19. Fig. 6 shows in partial cross section a wall section 27 with parts of two elements 1 supported in the wall 27 by at least part of the cross beam 7 and the slab 2. The top floor 17 stops short of the wall part 27A, as described before. In this embodiment a channel 26C is formed, extending through the beam 7 and the slab 2, at a side 13 of the beam 7 facing the space or pocket 16. Thus an open access to the channel 27 exists from the adjacent space or pocket 16 and vice versa. A channel section 26A is provided at the top side of the beam 7, next to the floor element 17, whereas a second channel part 26B extends through the slab 2. These channel sections 26A, B provided access into and from the wall parts 27A, for feeding utility lines 22. In fig. 7 a top view is shown of part of an element 1, showing the beam 7 with the channel 26C. A material section or element 26 as discussed with reference to for example fig. 2C and 2F can be provided in the channel 26C, to be broken away entirely or in part, for feeding one or more lines 22. Alternatively the channel 26C or for example one or more sections 26A, 26B thereof can be open or opened in production of the element 1, or directly thereafter. The channel 26C therefore is or can be brought into communication with at least one adjacent pocket 16. The cross beam preferably is free of openings extending from a pocket 16 and/or a channel 26C to a side 12 of the cross beam opposite the pocket, in order to maintain for example acoustical and air separation of the pocket and a void 27C that could be available in the wall 27 and/or from spaced at an opposite side of the wall 27.

In fig. 5 A in top view schematically different sizes of elements 1 are shown in one drawing. The length L is identical for all of these elements, whereas the width WA is different. This can for example be modular in the sense that the width WA is increased between elements by a regular interval, such as for example but not limited to 10 cm. As can be seen in fig. 5A, by way of example only, the first four elements 1 from the right hand side have widths WA such that there are only two outer longitudinal beams 3A, B and no intermediate beam 3C. In the further seven elements 1 shown in this range there is an intermediate beam 3C, which is spaced apart from the one outer beam 3A at a fixed distance Dl and from the other of the outer beams 3B at a variable distance D2. This allows for a large number of compatible end elements 1A. End element 1A has to be understood as meaning an element 1 compatible with further elements 1, but having a different width WA, which can be used at one or either end 103 of a floor 100 but can also be used between two elements 1. In fig. 5B the elements 1A are shown in longitudinal section and in longitudinal side view, showing the openings 9 and 8. In fig. 5C for four elements 1A of the range of elements of fig. 5A a cross sectional view is shown, showing the outer beams 3A, B and, if available, an intermediate beam 3C. It shall be clear that such range could be complemented by additional elements having two or more intermediate beams, having larger widths WA.

With elements 1 and 1A any length L of a floor 100 can be made, allowing easy access to each of the pockets 16. The pockets can be used in the same or similar way as for example a crawling space or space between floor and ceiling in a known building, but can be easier in access and maintenance. Moreover, such crawling space can be provided between all floors in a multi storey building, wherein access is provided from the living accommodation above the space, even at the elevated stories.

The invention is by no means limited to any or all of the embodiment shown in the drawings. Many variations thereof are within the invention as claimed, including at least all combinations of parts of such embodiments.

Elements 1, 1A can be made from any suitable material. Preferably they are moulded in a substantially closed mould, for integrally forming slabs and beams. In another embodiment one or more of the beams can be provided by mounting them on or to the slab and/or by providing them as inserts in a mould, to be moulded into the elements. These beams can then also be made partly or entirely of a different material, for example metal. Moreover, such beams could be made hollow. Cross beams are preferably at least provided at one, more preferable at least at both opposite ends of an element. The openings 9 are shown as substantially flush with an upper surface of the slab. They can also be orientated differently, for example in or near an upper surface of the beams. The beams 3 could also be orientated partly or all differently from parallel to each other, for example across the slab in angled orientation relative to each other and/or sides 5, 6 of the element 1, for example but not limited to crisscross, forming a cellular structure, such as for example a honeycomb type construction, for example for increased strength.

Claims

1. Floor system, comprising a series of concrete prefab elements, which prefab elements comprise a series of longitudinal beams at an upper side, on a slab, and at least two cross beams, cover elements carried on said beams, wherein a pocket is provided between two adjacent beams, the cross beams and a cover element, at least some of the prefab elements comprising entry and/or exit elements for access into and/or from the pockets through at least one of the cover element and a cross beam.

2. Floor system, wherein at least one of said cover elements comprises an opening, closed by a lid which is provided with a smaller opening for feeding a supply pipe or line to or from the pocket below the cover element.

3. Floor system according to claim 2, wherein the supply pipe or line is connected to a further supply pipe or line in said pocket, preferably in or below said opening.

4. Floor system according to any one of the previous claims, wherein at least one of the beams, especially at least one of the cross beams is provided near the cover element carried on said beam, over at least part of it's length, with at least one break element which is preferably softer and/or more brittle than the material of the beam.

5. Floor system according to claim 4, wherein said at least one break element is at least partly provided at a side of said beam facing the pocket.

6. Floor system according to claim 4, wherein said break element is provided in an opening extending through said beam, preferably closing off said opening.

7. Floor system according to claim 6, wherein said at least one break element is provided in a longitudinal beam extending along an outer

longitudinal side of the concrete prefab element, which beam is preferably is designed to be carried on and/or for carrying part of a wall of a building in which the floor system is positioned, preferably an outer wall of said building.

8. Floor system according to any one of the previous claims, wherein at least a number of the concrete prefab elements has at least three beams, wherein at least two separate cover elements are carried, each by two adjacent beams of said at least three beams, wherein the cover elements are preferably carried by at least one stepped upper surface of a beam.

9. Floor system according to any one of the previous claims, wherein On the beams of the concrete prefab elements strips of isolating, especially acoustically isolating strips are provided, which strips on the cross beams are provided on a part of the upper surfaces near the pockets only, ending spaced apart from an opposite outer edge of said cross beams.

10. Concrete floor element for a floor system of any one of claim 1 - 9.

11. Building provided with a floor system according to any one of claims 1 - 9.

12. Method for forming a floor, wherein a concrete prefab floor element as described in any one of claims 1 - 10 is placed on at least two carrier elements, such as walls or pillars, near opposite longitudinal ends, wherein utility lines or pipes are placed in or through the pockets between adjacent beams, in at least longitudinal and/or cross direction of the element, with an end of the line or pipe below a top surface of the beams, where after a cover element is placed over the pocket, with an opening over said end and then a utility pipe or line is connected through the opening to said end, where after the opening is closed around the utility pipe or line extending through said opening.

13. Method according to claim 12, wherein a closure element, such as a ring, is provided around the utility pipe or line, closing off the opening.

14. Method according to claim 12 or 13, wherein the utility pipe or line is fed through a series of adjacent prefab elements, preferably from an end of the series at a side wall.

15. Floor system according to any one of claims 1 - 8, wherein the opening in the cross beam extends from a surface of the cross beam facing a pocket of the element between beams to a top surface of the cross beam and/or through the slab to a side of the slab facing away from the cross beam.

16. Floor system according to any one of claims 1 - 8 or 15, wherein the opening in the cross beam forms at least part of a substantially vertical channel through the cross beam and the slab, which channel is or can be brought into communication with a pocket between beams of the element.

17. Floor system according to any one of claims 1 - 8, 15 or 16, wherein at least one utility line extends from a pocket between beams through said opening in a cross beam into a wall section above and/or below said cross beam and/or slab, spaced apart from a side of the cross beam opposite said pocket.

18. Floor system according to any one of claims 1 - 8, wherein a utility unit or wall section is mounted on or above the cover element, into which a utility line extending through said opening in the cover element extends, preferably permanently.