EP0295417B1 - Composite building slab, particularly for sectional false floors - Google Patents

Abstract

In previous composite building slabs for sectional false floors, which are supported at their four corners and consist of an upwardly open trough produced from tension-proof material and of a filling of compression-proof material, e.g. anhydrite, a greater deflection is produced, under load, at the edge of the slab than in the centre of the slab, which is undesirable. In order substantially to even out the load-bearing capacity and security of composite building slabs of the above type against breaking at the edge of and in the centre of the slab, provision is made on the side walls (6g) of the trough (3g) for a reinforcement which is virtually at the height of the slab and is non-positively connected to the base (5) of the trough. In addition or alternatively to this, it is also possible to increase at least twofold the density and strength of the filling (2) in the edge region of the composite building slab (10g) relative to the remaining region towards the centre of the slab. <IMAGE>

Description

The invention relates to a composite building board for raised floors for support at the corners, consisting of an open top, made of tensile material, preferably sheet steel, and a filling of pressure-resistant material, the density and strength of which can vary within a relatively wide range, and with anchoring means in the tub to achieve the composite effect between the filling and the tub and a reinforcement connected to the tub bottom, the tub being made in one piece from a sheet metal plate by bending edge strips between cut corners and welding the abutting edges to the corners of the tub.

From DE-PS 20 04 101 a composite building board is known which is similar to the building board referred to above and which has a tub made of sheet steel which forms the outer reinforcement of the board and a pressure-resistant mass embedded in the tub, usually concrete or anhydrite. This tub is manufactured using the deep-drawing process, which has the consequence that the material thickness on its upwardly drawn side walls is less than the material thickness of the tub bottom. For this reason in particular, the load-bearing capacity or resilience of such composite building boards is significantly greater in the middle than at their edge. Therefore, there is a risk that these composite building boards under load, for. B. by driving with a heavy file car, the plate edge always bends more than the middle of the plate. This creates a step and each time the file trolley bumps against the step creates a dynamic load which, if repeated, can lead to permanent deformation of the composite building board or even material destruction (cracking in the tub and / or filling).

The disadvantages described above also occur in composite building boards, in which the material thickness of the side walls is equal to that of the tub floor and / or in accordance with DE-OS 25 45 854, reinforcement bars are welded to the tub floor in addition to the side walls. Even with the last-mentioned composite building boards, the deflection at the board edge is greater than in the center of the board when the load is correspondingly high, since the reinforcing bars welded to the tub floor do not sufficiently increase the moment of inertia and section modulus at the board edge.

In other known composite building board designs, in which the reinforcement is traditionally embedded in the interior of the concrete or the like (cf. e.g. DE-PS 26 16 317), compared to the composite building boards of the type described at the beginning with a trough-shaped outer reinforcement, the lightweight design number , d. H. the relationship between load capacity and weight of the composite building board inherently much less favorable, so that for this reason they can be disregarded here.

GB-A-616 468 also discloses several variants of base plates, all of which have a trough-shaped body which has a filling made of pressure-resistant material, e.g. B. contains concrete. In all the embodiments of base plates described in this patent specification, however, the trough base bulges inwards away from the plate edges, so that the filling is made of pressure-resistant Material in the edge area of the base plate has the largest cross section, which becomes increasingly smaller towards the center of the plate. This also increases the load-bearing capacity and security of the composite building board against breakage at the edge. However, there is no indication in this patent that the load-bearing capacity of the composite building board against breakage at the edge and in the middle of the board should be made essentially the same. Due to the arched trough floor, these known composite building boards cannot be divided into sections, as is often required when installing raised floors. These known composite building boards are therefore practically unsuitable for raised floors. This applies in particular to the embodiments with step-shaped side walls when viewed in section, since here, as is customary in the case of raised floors, there is difficulty in supporting the plates at the corners. It is also known from this patent to manufacture the tub in one piece from a sheet metal plate by bending edge strips between cut corners and welding the abutting edges to the corners of the tub. However, as already mentioned, an arched sheet metal plate is used for this and tubs with the stepped side walls are produced from these blanks. In order to stabilize the longitudinal side walls of these tubs, strips are also inserted into the tub and connected to the side walls.

The invention has for its object to provide a composite building board with an outer reinforcement trough made of tensile material and a filling of pressure-resistant material such that under the same load in the middle or at the edges their deflection is practically the same size at these points .

According to the invention, a first solution to the above object is that the reinforcement on the side walls the tub is provided and formed in that the edge strips of a flat sheet metal plate are folded over at least to double the thickness of the tub side walls, bent up and welded at their abutting edges, so that the load-bearing capacity and security of the composite panel against breakage at the edge and in the center of the panel in is substantially level or the same. A composite building board with the features according to the invention, supported at its corners, has the advantage that its load-bearing capacity in the edge area is matched to the load-bearing capacity in the middle of the board and the previously existing danger with known composite building boards, namely that of permanent deformation or even material destruction at the board edge due to the corresponding load, is significantly reduced. The invention also makes it easier to meet the requirement in practice than hitherto, according to which the load capacity of a raised floor slab is determined in that the deflection at the weakest point must not be greater than 1/300 of the support distance and, on the other hand, a certain security against breakage is guaranteed must, that is, the permissible load only a part, for. B. half the breaking load. The aforementioned deflection can namely be kept practically the same size at all points in the composite building board according to the invention - assuming an equal load at all these points - and preferably the reinforcement on the side walls of the tub is essentially plate-high, so that a correspondingly large moment of inertia receives.

It is also advantageous that the invention can also be used in connection with different filler material in order to obtain composite building boards of different weights. This is of great importance in terms of reducing manufacturing, freight and assembly costs. In other words, the invention enables the production of composite building boards of different weight with correspondingly different load-bearing capacity, but ensures in any case that the load-bearing capacity is practically the same at all points on the composite building board. The invention also very easily achieves a plate-high reinforcement on the side walls of the tub, while maintaining the material thickness, even in the edge region of the tub bottom.

Another solution to the above object is characterized in that the trough is made in two parts from a flat floor plate provided with anchoring means and a profile frame that also forms the reinforced side walls of the trough, the wall thickness of which is at least three times as large as the wall thickness of the floor plate, and that Floor plate with the profile frame by z. B. spot welding is connected so that the load-bearing capacity and safety of the composite panel against breakage at the edge and in the center of the panel is substantially level or the same. Such a trough, the reinforced side walls of which are formed by a profile frame, and which contains a simple flat floor plate as trough floor, is particularly inexpensive to manufacture and leads to a corresponding reduction in costs of the composite building board concerned.

If, according to a further embodiment of the invention, the edges of the floor panel are additionally deformed to increase the section modulus in the edge area of the building board, the bond effect between the filling made of pressure-resistant material and the tub in the edge area is also advantageously increased.

This is yet another embodiment of the invention characterized in that the angle profiles for reinforcing the tub side walls in the central region between the corners of the tub have a greater overall height and thus a greater section modulus than the areas adjacent to the corners of the tub. This achieves a reduction in the weight of the composite building board while maintaining the advantages of the invention.

Fig. 1a

eine Querschnittsansicht einer Verbundbauplatte bekannter Bauweise, abgestützt auf ihren Ecken und mit einer Belastung P an ihren Rändern sowie in der Mitte in Verbindung mit einer schematischen Darstellung der durch diese Belastungen hervorgerufenen Durchbiegung der Verbundbauplatte, zum besseren Verständnis übertrieben gezeichnet;

Fig. 1 b

eine der Figur 1 a ähnliche Querschnittsansicht, jedoch von einer Verbundbauplatte mit den erfindungsgemäßen Merkmalen, gleichfalls mit einer schematischen Darstellung der durch die Belastungen hervorgerufenen Durchbiegung der Verbundbauplatte;

Fig. 2 d bis 2 e

verschiedene Teil-Schnittansichten von Verbundbauplatten, bei welchen die Seitenwände der Wanne erfindungsgemäß unterschiedlich verstärkt sind;

Fig. 3 a bis 3 c

verschiedene Phasen bei der Herstellung einer Wanne mit verstärkten Seitenwänden aus einem ebenflächigen Blechzuschnitt durch Aufbiegen und Umschlagen von Randstreifen zwischen ausgeschnittenen Ecken für eine Verbundbauplatte entsprechend Figur 2 b und

Fig. 4

eine Schrägansicht einer aufgeschnittenen Verbundbauplatte entsprechend der Ausführungsform nach Figur 2e.

The invention is subsequently explained with reference to the drawings of exemplary embodiments. Show it:

Fig. 1a

a cross-sectional view of a composite building board of known construction, supported on its corners and with a load P at its edges and in the middle in conjunction with a schematic representation of the deflection caused by these loads of the composite building board, exaggerated for better understanding;

Fig. 1 b

a cross-sectional view similar to FIG. 1 a, but of a composite building board with the features according to the invention, likewise with a schematic representation of the deflection of the composite building board caused by the loads;

Fig. 2 d to 2 e

different partial sectional views of composite building boards, in which the side walls of the tub are differently reinforced according to the invention;

3 a to 3 c

Different phases in the manufacture of a tub with reinforced side walls from a flat sheet metal blank by bending and folding edge strips between cut corners for a composite building board according to Figure 2 b and

Fig. 4

an oblique view of a cut composite building board according to the embodiment of Figure 2e.

In Figure 1 a above is shown in section a composite building board (10) which is supported at its four corners on only schematically indicated footrests (11) and z. B. is used to produce a raised floor. The composite building board (10) has a trough (3) made of sheet steel with a filling (2) from one pressure-resistant material, e.g. B. concrete or anhydrite. The bonding effect between the tub (3) forming the outer reinforcement for the building board (10) and the filling (2) is achieved by anchoring means (4), which in the present case consist of openings with jagged edges (so-called punches) in the tub bottom (5) exist. The tub (3) made of sheet steel is manufactured using the deep-drawing process, the tub bottom (5) having the original sheet thickness S 1, while the side walls (6) have a sheet thickness S 2 that is reduced compared to the sheet thickness S 1 due to the deep-drawing process. The sectional view of the composite building board (10) schematically shows the deformation of the same under the action of a vertical load P at its edges or in the middle with the board (10) supported only at its four corners. It can be seen that with this known composite building board (10) the deflection hMa in the middle is significantly smaller than the deflection hRa at the board edges: the weakest points of the composite building board (10) are therefore at their edges and determine their resilience, but what is unfavorable. For the load capacity of raised floor panels, there is an international requirement that the deflection at the weakest point of the panel must not be greater than 1/300 of the support or column distance A.

FIG. 1 b shows a composite building board (10 g) which corresponds in its external dimensions to the composite building board (10) of FIG. 1 a and is also supported as a double floor board at its four corners on supports (11). The composite building board (10 g), however, has a trough (3 g) designed in accordance with the invention in accordance with the embodiment according to FIG. 2 e, so that under the same load conditions as in the example according to FIG The middle of the plate is essentially as large as the deflection hRb at the edges of the plate. In other words, the load-bearing capacity of the composite building board (10 g) is practically the same at its edges and in the middle of the board. The tub (3 g) (see also FIG. 2 e) of the composite building board (10 g) is made in two pieces. A profile frame (from a Z-profile) forms the reinforced side walls (6 g) of the tub (3 g), the thickness S 4 of which is a multiple (at least three times) of the wall thickness S 1 of a floor plate (7), which on the inwardly projecting legs of the profile frame, for. B. is fixed by welding spots (9). The bottom plate (7) is provided with the usual anchoring openings (4) for the filling (2) made of pressure-resistant material and it has an additional bevel (7 a) on its four edges, which increases the composite effect and at the same time also the edge area of the composite building board reinforced. In this exemplary embodiment, the filling (2) is of the same density and strength over the entire plate cross section. The reinforcement of the side walls (6 g) of the tub (3 g) in relation to the tub floor is in any case dimensioned such that the load-bearing capacity of the composite building board (10 g) is practically the same at its edges and in the middle.

The composite building board (10 f) shown in FIG. 2 d also contains a trough (3 f) made from two pieces. The side walls (6 f) of the tub (3 f) consist of an L-profile frame, the wall thickness S 4 of which is a multiple (at least three times) of the wall thickness S 1 of the floor plate (7). This bottom plate (7) is, for. B. by welding points (9) attached to the inwardly projecting legs of the profile frame and contains anchoring openings (4) for the filling (2), which are also provided in the side walls (6 f) of the tub (3 f). The load-bearing capacity of this composite building board (10 f) is at Support at the four corners on their edges and in the middle essentially the same. The filling (2) made of pressure-resistant material can have the same density and strength over the entire plate cross-section.

The composite building board shown in Figure 2 a (10 b) consists of a trough (3 b) made of sheet steel and a filling (2) made of pressure-resistant material, for. B. anhydrite. In this embodiment, the side walls (6 b) of the tub (3 b) are twice as thick as the tub bottom (5). This reinforcement of the side walls (6 b) of the tub (3 b) can, for. B. achieve by a manufacturing method, which will be explained with reference to Figures 3 a to 3 c. The filling (2) can be of the same density and strength over the entire plate cross-section.

The side walls of the tub can also be three or four times as thick as the bottom of the tub. Quadruple thickening is preferred.

In the exemplary embodiments according to FIGS. 2 b and 2 c, the side walls (6 d or 6 e) of the relevant troughs (3 d, 3 e) are reinforced in a manner similar to the exemplary embodiment according to FIG. 2 a, only in the composite building boards (10 d or 10 e) the folded edge strip angled on the outside or inside and additionally used to reinforce the tub side walls (6 d or 6 e). The punches (4) can also be used here for connection purposes.

The composite building board (10 g) shown only in partial section in FIG. 2 e is shown in more detail in FIG. 4. This figure shows that the side walls (6 g) of the tub (3 g) are formed from a Z-profile frame, which in turn is composed of four profile pieces (16) which are mitred at their ends (15) and are welded together. The profile frame forming the tub side walls (6 f) in the embodiment according to FIG. 2 d can also be produced in the same way. The upturns (7 a) on the base plate (7) or trough base can likewise be provided with openings (4) to further increase the bond effect between the trough (3 g) and the filling (2).

The sequence of figures 3 a to 3 c illustrates the manufacture of the tub (3 b) for the composite building board (10 b) according to FIG. 2 a, the side walls (6 b) of which have twice the thickness of the tub floor (5). The base material for the tub (3 b) is the flat sheet metal blank shown in FIG. 3 a, the external dimensions A 1 and B 1 of which are 4 H greater than the bottom dimensions A 2 and B 2 of the finished tub, which is inclined in FIG. 3 c ( 3 b). At the corners of the sheet metal blank of FIG. 3a, cutouts (26) are punched out in such a way that edge strips (21) with a transverse dimension 2 H are formed between the punched out corners.

Then, according to FIG. 3 b, the edge strips (21) are first folded around bending lines (24 a) and thus the material thickness is doubled before the doubled edge strips are then bent upwards around the bending lines (24 b) until they meet at their ends. At your joints, the doubled edge strips (21) are finally z. B. connected by welds (25). The finished tub (3 b) is shown in Figure 3 c with part of the filling (2) made of pressure-resistant material.

A wide variety of pressure-resistant materials can be used as the filling (2), depending on the requirements for the composite building boards. For particularly high-quality composite building boards, e.g. B., as before, mineral fillers provided in the form of anhydrite or concrete. For composite building boards, to which lower demands are made, on the other hand, specifically lighter fillings, e.g. B. with plastic as a binder (synthetic resin lightweight concrete) or gypsum-bound fillers with light aggregates (z. B. wood chips or perlite). The density and the compressive strength of the filling (2) can be varied within wide limits, but the wall thickness S 1 of the tub floor must always be adjusted to the density of the filling (2).

Claims (4)

1. Composite building slab for false floors, for supporting at the corners, consisting of an upwardly open tray (3b) made of a material, preferably sheet steel, which is strong in tension, and a filling (2) of compressively strong material, whose density and strength can vary over a relatively large range, as well as with anchoring means (4) in the tray (3b) for achieving the compound action between the filling (2) and the tray (3b) and a reinforcement connected non-positively to the tray bottom (5), wherein the tray (3b) is made in one piece from a sheet by bending up edge strips between cut-out corners (26) and welding the butt edges (25) at the corners of the tray (3b), characterized in that the reinforcement is provided at the sidewalls (6b) of the tray (3b) and is so formed that the edge strips (21) of a flat sheet are folded over to at least double the thickness of the tray sidewalls (6b), are bent up and are welded at their butt edges (25), so that the load-bearing capacity and security against fracture of the composite slab (10b) are substantially equalised or equal at the edge and in the slab middle.
2. Composite building slab for false floors, for supporting at the corners, consisting of an upwardly open tray (3g) made of a material, preferably sheet steel, which is strong in tension, and a filling (2) of compressively strong material, whose density and strength can vary over a relatively large range, as well as with anchoring means (4) in the tray (3g) for achieving the compound action between the filling (2) and the tray (3g) and a reinforcement connected non-positively to the tray bottom (7), characterized in that the tray (3g) is formed in two parts from a flat bottom sheet (7) provided with anchoring means (4) and a profiled frame forming at the same time the reinforced sidewalls of the tray (3g), the wall thickness (S4) of which is at least twice as the wall thickness (S1) of the bottom sheet (7), and in that the bottom sheet (7) is connected to the profiled frame e.g. by spot welding (9), so that the load-bearing capacity and security against fracture of the composite slab (10g) are substantially equalised or equal at the edge and in the slab middle.
3. Composite building slab according to claim 2, characterized in that the edges (7a) of the bottom sheet (7) are additionally shaped to increase the moment of resistance in the edge region of the building slab (10g).
4. Composite building slab according to claim 2, characterized in that the angular profiles for reinforcing the tray sidewalls (6g) in the central region between the corners of the tray have a greater structural height and thus a greater moment of resistance than the regions adjoining the corners of the tray (10g).

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