WO2008133516A1

WO2008133516A1 - Prefabricated floor element and floating construction with a number of such floor elements

Info

Publication number: WO2008133516A1
Application number: PCT/NL2008/050256
Authority: WO
Inventors: Hein Douwinus Voskamp; Jelle Claus Vedder; Michaël Jacobus Gerhardus BARTELS
Original assignee: Aqualife B.V.
Priority date: 2007-04-29
Filing date: 2008-04-25
Publication date: 2008-11-06
Also published as: NL2001523C2

Abstract

A prefabricated floor element comprises: two slabs of reinforced concrete which extend in mutually parallel relation with respective reinforcements of first steel bars; and a pattern, mutually connecting the slabs, of second steel bars which are disposed roughly in zigzag formation in two mutually independent directions and which are fixedly connected to the first bars, for instance by welding, and are embedded with their end zones in the concrete of the slabs. The floor element preferably further comprises: coupling means for coupling the floor element to a similar floor element, which coupling means can for instance comprise: two clamps which engage on the first and the second slabs of each of the two floor elements over the whole relevant edge length, and which each engage on two oppositely directed edge surfaces of each relevant slab.

Description

PREFABRICATED FLOOR ELEMENT AND FLOATING CONSTRUCTION WITH A NUMBER OF SUCH FLOOR ELEMENTS

The current market making use of concrete floating foundations can be specified as follows.

A known floating construction comprises for instance: - a concrete container manufactured in prefabricated form in a factory, after which a building, such as a dwelling, is constructed on the container, or

- a reverse concrete container filled with EPS (expanded polystyrene) which is produced in prefabricated form in the factory, after which a building is constructed on the container, or

- an EPS bed finished with fibre-reinforced concrete. This foundation is laid and poured on site. The buildings are erected on site. Such known systems on the basis of concrete have a number of deficiencies and limitations. The most important of these are:

- The prefabricated elements are difficult or even impossible to transport by road. - It is difficult or even impossible to couple the prefabricated elements to each other with a sufficient rigidity and strength.

- It is difficult and usually even impossible to later lay conduits and cables in the foundation for a building to be supported. A very precise preparation for such installations is essential under all circumstances. Later modifications cannot be carried out.

- There is a great lack of flexibility in the final form of the foundation. - The prefabricated elements have poor resistance to high dynamic and uneven loads on the foundation.

- A specific finish to the top side of a platform is essential for the purpose of placing buildings.

It is an object of the invention to obviate the above specified deficiencies and limitations of the prior art. In respect of the above, the invention provides a prefabricated floor element which is characterized by: two slabs of reinforced concrete which extend in mutually parallel relation, and which are for instance substantially congruent, with respective reinforcements of first steel bars; and a pattern, mutually connecting the slabs, of second steel bars which are disposed roughly in zigzag formation in two mutually independent directions and which are fixedly connected to the first bars, for instance by welding, and are embedded with their end zones in the concrete of the slabs.

In a manner more or less similar to the technique of a sandwich panel, such a prefabricated floor element can be embodied with a very low weight such that it has great bending stiffness and strength and has great shear strength, and tolerates a large span at a high floor load per square metre.

Because a floor element is completely hollow, it is possible to arrange conduits, cables and similar provisions in the floor at a later stage. By creating a distance between the concrete slabs and by using as core the second steel bars, which are moreover embedded over some distance with their end zones into the concrete of the slabs, this in a manner somewhat similar to a sandwich panel, it is possible as stated to obtain a high resistance to sagging in combination with a very low weight relative to a comparable monolithic structure of reinforced concrete. The said distance can be chosen subject to desired bending stiffness and strength.

Attention is drawn to the problem according to the prior art wherein prefabricated floor elements can withstand sagging to only a very limited extent, particularly in the case of uneven loads. Attention is drawn to the fact that a prefabricated floor element according to the invention can also comprise more than two slabs of reinforced concrete extending in mutually parallel relation. In such a case the floor element comprises at least two patterns of the zigzag bars mutually connecting adjacent slabs. According to an important aspect of the invention, the prefabricated floor element is characterized by coupling means for coupling the floor element to a similar floor element, these coupling means comprising: two clamps which engage on the first and the second slabs of each of the two floor elements over the whole relevant edge length, and which each engage on two oppositely directed edge surfaces of each relevant slab. A floor assembled in such a manner from two or more floor elements has a great strength and bending stiffness, in combination with a low weight.

According to a subsequent aspect of the invention, the prefabricated floor element has the special feature that each edge zone of the slabs has a step-like recess on the inward directed side; and the clamp has a first clamping element with a form corresponding to the form of the edge zone, and a second clamping element engages on the other sides of the two slabs.

The floor element according to the two above described aspects of the invention preferably has the special feature that the clamp is a screw clamp. In another embodiment the prefabricated floor element according to the invention has the special feature that two floor elements are coupled to each other by connecting together the first and/or the second steel bars by welding.

According to a subsequent significant aspect of the invention, the floor element has the special feature that the upper slab is embodied such that it is suitable to serve as finished floor for a building to be supported by a number of coupled floor elements. With this embodiment the upper surface of the floor, owing to the process and the construction of the floor parts, immediately becomes the finished floor for the building supported thereby. A separate finishing of the floor therefore becomes unnecessary, and this has the great effect of saving time and reducing costs. The invention further relates to a floating construction, comprising a number of mutually coupled, generally block-like floating bodies disposed in their longitudinal direction in mutually parallel relation. According to the invention this floating construction is characterized by a number of prefabricated floor elements with said coupling means, which coupling means are coupled in mutually parallel relation by coupling means as specified above, wherein their longitudinal direction is preferably oriented transversely of the longitudinal direction of the floating bodies. According to another important aspect of the invention, the floating construction has the special feature that the upper plates of mutually adjacent floor elements are located at a mutual distance such that the space in the floor elements is accessible from above, which said mutual distance can be spanned by a closing plate.

A floor according to the invention can be given a floating form by arranging EPS, a metal container, a concrete or a plastic container or the like, optionally protected against corrosion, erosion or attack by vermin, as buoyant element under the floor. As a result the floor extends completely above the water. This makes it possible to couple the upper plate and the lower plate of a floor element to another floating floor element in the manner as described above. Using the invention it is thus possible to couple a coupling with a high degree of strength and rigidity in combination with a low weight.

The floor elements can in principle have any desired size.

It is also possible to make each floor element connectable on all sides, whereby any desired form of a floor can in principle be realized on the basis of prefabricated floor elements according to the invention. Because the prefabricated floor elements can be coupled later on site, it is also possible to give the floor elements dimensions such that they can be transported relatively easily by road or by water. Otherwise than in the prior art, the location and the access roads hereby no longer represent a limitation for the application of floating dwellings or other building structures, roads, gardens or other structures.

The invention will now be elucidated with reference to the accompanying drawings. In the drawings: figures IA and IB show perspective views of a floating construction with a number of prefabricated floor elements according to the invention in two embodiments; figures 2A and 2B show perspective views of a part of the floating constructions according to figures IA and IB; figure 3 is a top view of the platform of figure IA with dimensions of 15 m x 21 m; figure 4A shows detail IV of figure 1 on enlarged scale; figure 4B shows a view corresponding to figure 4A of an alternative; figure 5A shows detail V of figure 1; figure 5B shows a view corresponding to figure 5A of an alternative; figure 6 is a perspective view of a floating construction according to the invention; figure 7 is a side view of the construction according to figure 6; figure 8 is a front view of the construction according to figure 6, wherein the coupling system is visible; figure 9 shows detail IX of figure 8 on enlarged scale; figure 10 shows a perspective partial view of the structure with zigzag bars and reinforcement according to the invention; figure 11 is a side view of the structure according to figure 10, wherein the method of coupling is clearly shown; figure 12 shows detail XII of figure 11; figure 13 is a top view of the structure according to figures 10, 11 and 12; figure 14 is a top view in which the couplings with bolt constructions are shown; and figure 15 is a side view of the couplings according to figure 14.

Figure IA shows an example of a floating construction 5, the top view of which is shown in figure 3. Floating construction 5 comprises a number of buoyant elements 2 supporting prefabricated floor elements 1 disposed in mutually parallel relation (see also figure 2).

Each prefabricated floor element 1 comprises two mutually parallel, substantially congruent slabs 6, 7 of concrete with respective reinforcements of first steel bars 8, 9 respectively. Floor element 1 further comprises a pattern, mutually connecting slabs 6, 7, of second steel bars 10 which are disposed roughly in zigzag formation in two mutually independent directions x, y (see figure 2) and which are fixedly connected to first bars 8, 9 and embedded with their respective end zones 11, 12 in the concrete of respective slabs 6, 7. See also figure 4 in this respect. On the basis of figure 2 it will be apparent that owing to the three-dimensional zigzag structure of the pattern of second bars 10 over the mutual distance a between slabs 6, 7 and the embedding of the end zones 11, 12 therein, a very great bending stiffness, strength and shear strength is realized in both directions x and y-

Floating construction 5 is protected by a protective edge 3, embodied for instance as a number of mutually connecting prefabricated elements 18 of concrete or other suitable material.

As shown in figures 2B and 6, upper plate 6 can be covered by respective cover plates 20.

It is important according to the invention that use can be made of removable cover plates, all of which are designated with reference numeral 19 and which, when removed, provide the option of reaching the intermediate space between slabs 6, 7, for instance for the purpose of arranging conduits, cables and other provisions, for adjustment, repair and maintenance. It is important that the prefabricated floor elements according to the invention can be coupled to each other for bending stiffness and in force- transmitting manner. An example of an embodiment of this principle according to the invention is shown in figure 4. The coupling clamps 13 shown therein couple corresponding slabs 6, 7 of adjacent floor elements 1,1' to each other according to the invention. In this embodiment each edge zone 14, 14' of each slab has on its inward directed side a step-like recess 15, 15'. A first clamping element 17 has a form corresponding to the form of edge zone 14, 14' and a second clamping element in the form of a clamping plate or clamping strip 17' engages on the other side of both slabs. Figure 6 shows an assembly 21 of two floating constructions 5 as according to figure 2A. These constructions 5 are coupled to each other in a manner to be described hereinbelow. Upper slab 6 of figure 2A is covered in the embodiment according to figure 6 by a cover plate 20. As shown in figure 9, the longitudinal edges of plates 20 are at a mutual distance which is filled with cover plates 19. These cover plates 19 are supported on their edges by the corresponding longitudinal edges of upper slabs 6, 6' which are left clear by the cover plates 20, 20" of slightly smaller dimensions. Because plates 19 and 20 have the same thickness, their upper surfaces lie in an at least substantially flat plane.

Figure 7 shows floating construction 5 from the side. The prefabricated floor element 1 is supported by buoyant element 2 or an assembly of such buoyant elements. A buoyant element can for instance be an open container manufactured from any desired and suitable material, for instance from concrete but also from expanded polystyrene, optionally provided with a protective casing. The height of buoyant elements 2, 2' depends on the required buoyancy and is selected in the light thereof during design of construction 5.

Figures 8 and 9 show that the floating constructions or modules 5 are coupled to each other at the position of floor elements 1, I¹. The often very great forces which occur can hereby be transmitted in excellent manner. Owing to the modular structure the floating constructions can be coupled without any limitation in both their width direction and their length direction. The space between the two at the position of upper slabs 6, indicated with 22 in figure 4B, can be filled by a cover plate 19 which consists for instance of calcium sulphate and which can be temporarily removed, whereby access is gained to the space between slabs 6 and I₁ for instance for the purpose of laying cables, pipes and conduits and/or for maintenance and repair purposes. The distance between upper slab 6 and lower slab 7 depends on the required resistance to sagging and also on the diameters of the conduits to be laid. In respect of the resistance to sagging it is noted that this resistance becomes greater as the mutual distance between slabs 5 and 6 increases.

Figure 9 shows clearly the manner in which floor elements 1, 1' can be coupled to each other by means of bolt connections, all designated with 23.

It is noted that the largest possible modular size is sought in order to limit as far as possible the costs of the required coupling elements and mutual coupling thereof. This depends on the intended application, the logistical possibilities and the production options. Figures 10-15 show stripped views of the various metal components forming part of the floor elements according to the invention and the coupling therebetween .

Figures 10 and 11 show that the forces occurring during the use of floating constructions in modular assembly with each other are absorbed by the reinforcement in the form of the lattice girders and the reinforcement in longitudinal direction and transverse direction. The diameter of the reinforcing bars and the quantity of reinforcement to be applied depends on the forces to be accommodated. The reinforcements of prefabricated floor elements to be connected to each other are structurally interconnected. The reinforcement is preferably fully welded together, whereby the construction is best able to absorb the very great forces which occur. As the figures show, a series of framework constructions and triangular bracings is created, whereby the fully assembled structure is very well able to absorb sagging, tensile forces and pressure forces .

Figures 12 and 13 shown that the couplings 23 are connected to reinforcing bars 8, 9. In this way the framework construction shown particularly in figure 10 can be interconnected from the one module to the other. The construction is able to absorb extremely great forces while retaining its integrity. Figures 14 and 15 show that the couplings, all designated with 23, are realized on the top side with threaded rods which can optionally be weighted and stiffened if this is required. On the underside use is made in this embodiment of bolts. These can also be weighted or stiffened if this is required in respect of the design load.

The spaces between the couplings and the space between the nuts and the sleeve can be filled with damping material. Dynamic loads can hereby be absorbed. In this embodiment the upper coupling takes an adjustable form, whereby tolerances can be accommodated. In addition, this implementation has the advantage that effecting of the coupling is hereby simplified, particularly on an unstable and even moving surface such as water. This because the shown threaded rods can be pushed easily into the sleeves and later fixed in order to impart the desired stiffness to the modular construction, or construction platform. The advantages of the invention can be briefly summarized as follows: - The floor elements according to the invention can be given a modular form and be assembled as such to form larger units, in principle without any limitation in dimensioning. The above described bolt connections are very suitable for this purpose. The advantage of bolt connections over welded connections is further that a bolt connection can, if desired, be released again, other than a welded connection which for this purpose would require intervention in the overall construction, such as grinding away, sawing or a thermal treatment such as flame cutting. - A floor element, and also an assembly consisting of a plurality of floor elements, has a very high resistance to sagging due to the structurally fully welded lattice girders, i.e. roughly in zigzag formation.

- Assemblies or platforms can be modified afterwards due to the above described upper couplings on the basis of threaded rods. Deviations occurring in production can hereby be readily compensated. It is also possible to optionally realize a curved form of the upper surface, thereby increasing still further the resistance to sagging.

- Couplings can be made flexible by applying plates of rubber or a rubber-like material. Fatigue problems, for instance in the application for floating roads or dynamic environments (heavy swell) , can in this way be prevented, or at least substantially alleviated.

- The top side of a platform is immediately suitable for buildings since the floor emerges "clean" from the shuttering. For this purpose the floor is produced in a special way, whereby the outer sides of the floor are always given a smooth finish.

- Owing to the floor construction and the use of the calcium sulphate cover plates or filler plates the space between upper slab 6 and lower slab 7 of floor element 1 can be utilized for wires, cables, pipes, conduits, ballast tanks and other provisions important for the intended use of the building supported by an assembly. Such components can also be mounted later, for instance by temporarily removing cover plates 19 at least partially. The option of later fitting is very advantageous, since it can result in a great cost-saving in the engineering process. The flexibility in realizing a desired unit with many varying functions nevertheless remains fully guaranteed.

- Owing to the modular construction and the prefabricated production of the modules it is possible to transport the platform modules by land, by sea and even by air, for instance by means of cargo helicopters.

Claims

1. Prefabricated floor element characterized by two slabs of reinforced concrete which extend in mutually parallel relation with respective reinforcements of first steel bars; and a pattern, mutually connecting the slabs, of second steel bars which are disposed roughly in zigzag formation in two mutually independent directions and which are fixedly connected to the first bars, for instance by welding, and are embedded with their end zones in the concrete of the slabs.

2. Prefabricated floor element as claimed in claim

characterized by coupling means for coupling the floor element to a similar floor element, these coupling means comprising: two clamps which engage on the first and the second slabs of each of the two floor elements over the whole relevant edge length, and which each engage on two oppositely directed edge surfaces of each relevant slab.

3. Prefabricated floor element as claimed in claim 2, characterized in that each edge zone of the slabs has a step-like recess on the inward directed side; and the clamp has a first clamping element with a form corresponding to the form of the edge zone, and a second clamping element engages on the other sides of the two slabs.

4. Prefabricated floor element as claimed in either of the claims 2 and 3, characterized in that the clamp is a screw clamp.

5. Prefabricated floor element as claimed in claim 2, characterized in that two floor elements are coupled to each other by connecting together the first and/or the second steel bars by welding.

6. Prefabricated floor element as claimed in any of the foregoing claims, characterized in that the upper slab is embodied such that it is suitable to serve as finished floor for a building to be supported by a number of coupled floor elements.

7. Floating construction, comprising a number of mutually coupled, generally block-like floating bodies disposed in their longitudinal direction in mutually parallel relation characterized by a number of prefabricated floor elements as claimed in claim 2 which are coupled in mutually parallel relation by coupling means as specified in any of the claims 2-5, wherein their longitudinal direction is preferably oriented transversely of the longitudinal direction of the floating bodies.

8. The floating construction as claimed in claim 7, wherein the upper plates of mutually adjacent floor elements are located at a mutual distance such that the space in the floor elements is accessible from above, which said mutual distance can be spanned by a closing plate.