The invention relates to a composite plate, especially for raised floors to be supported at the corners, consisting of a shell which is open at the top, manufactured of tension-resistant material, preferably sheet steel, and a filling of pressure-resistant material, of which the density and strength can vary within a relatively wide range, and also with anchoring means in the shell for generating a binding effect between the filling and the shell and a reinforcement connected with the bottom plate of the shell.
A composite plate which is similar to the above structural plate is known from German Patent 20 04 101 and has a shell of sheet steel forming the outside wrapper of the plate and also has a pressure-resistant material embedded in the shell, and the pressure-resistant material is generally concrete or anhydrite. This shell is produced by the deep-drawing manufacturing process, the result of which is that the material of the side walls which are drawn upward during manufacture is less thick than the material of the bottom plate of the shell. Because of this more than anything else, the bearing strength or respectively the carrying capacity of such a composite plate is considerably greater in the middle than at its border. The danger therefore arises that when this composite plate is carrying a load, for instance, when it is travelling with a heavy truck filled with files, the border of the plate becomes gradually further deflected than the middle of the plate. Thus a step occurs in the configuration of the plate and with each impact of the truck of files against said step there occurs one more instance of dynamic stress, which with repetition can lead to permanent deformation of the composite plate or even to destruction of the material (formation of tears in the shell and/or the filling).
The drawbacks described above also arise with composite plates in which the thickness of the material of the side walls is identical to that of the floor plate of the shell and/or in which, as in German Offenlegungsschrift 24 45 854, reinforcement rods are welded to the floor plate of the shell adjacent to the side walls. With the just aforementioned composite plates, too, upon application of progressively higher stress the deflection at the border of the plate is greater than the middle of the plate, since the moments of inertia and resistance on the border of the plate are not sufficiently heightened as a result of the presence of reinforcement rods welded to the floor plate of the shell.
With known composite plate embodiments, in which the armoring traditionally is embedded within the concrete or the like (cf. for instance German Patent 26 16 317), in comparison with the composite plate of the presently described structural type with a shell-shaped outside wrapper, the light construction characteristics, in other words the ratio between the carrying capacity of the composite plate of Haus and its own weight, is considerably less favorable, so that simply because of these factors these composite plates do not even come into consideration in this case.