PROCEDURE FOR MANUFACTURING A COMPOUND SLAB

Abstract: A load-bearing compound slab which has been manufactured by combining a corrugated steel sheet (1) by means of dowels (2) with a concrete slab, and the procedure for manufacturing such a structure. Compared with a standard compound slab of prior art, the manufacturing method differs in that the slab is poured upside down, that the spikes of the steel sheet are pressed into the concrete mix in the mould before its hardening. In this way is obtained a structure in which the material utilization is more advantageous than in any problem solution known heretofore, and thereby savings are gained in the manufacturing, transporting and installation costs.

Description: Procedure for manufacturing a compound slab The present invention concerns a procedure for ' manufacturing a compound structure as specified in claim 1 for load-bearing hori¬ zontal structural parts of buildings, such as base floors, inter¬ mediate floors and ceilings. The use of compound slabs is previously known in itself, since by combining different materials - most usually steel and concrete - is achieved advantageous utilization of the material's properties. Also known is the manufacturing of a compound slab in. that a cor¬ rugated steel sheet is combined with concrete poured thereupon, by means of_ dowels cut out by machine means from every second wave-trough of the sheet (e.g. the Homecon compound slab). In a slab manufactured in the way just described, the material utilization is not optimized: the concrete enclosed within the folds is nearly stress-free, thereby unnecessarily adding to the structure's proper weight and causing unnecessary costs. The said structure is in fact best appropriate for slabs which are concreted on the site-, because it is simple to produce, the corrugated sheet also serving as mould. A wall slab manufacturing method is also known (German application print No. 2415 647) wherein the element has been manufactured by first pouring the concrete in a mould and pressing into it, close to the surface, a corrugated steel sheet provided with reinforce¬ ment rods. These reinforcement rods are affixed to the steel sheet by clamps in manual work, and therefore the manufacturing is com¬ plicated and expensive. However, a slab of this type is not in¬ tended to stand up to the loads occurring in intermediate floors because the concrete layer is comparatively thin. The invention to be disclosed here is characterized in that it is made in a mould, advantageously in a horizontal mould, upside down. On the bottom of the mould is poured a concrete layer of requisite thickness. While the concrete is still pliable, on top of it is lowered a corrugated sheet with mechanically punched-out spikes having a length preferably equal to the thickness of the slab. The corrugated sheet is pressed down so that the spikes bear on the bottom of the mould, and- the concrete is allowed to harden. During transport to its final location in the building, the slab is in¬ verted so that the concrete slab will constitute the top surface of the compound slab. Compared with prior art, this construction affords the advantage of lesser material consumption, and thereby lower manufacturing, transport and installation costs. Since the thickness of the con¬ crete slab can be minimized, greater speed is also achieved in the mould turnover as a result of shorter heating periods. Another advantage is that the floor surface meant to be smooth is poured - against the mould, whereby no grinding is required. The " mould may also be provided with sides producing the required marginal shapes. It is an important advantage that in the upside down manufacturing the required pre-camber is achievable by a simple technique, for instance with the aid of weights of suitable magnitude. The invention is more closely described in the following with reference to the- attached figures, of which Fig. 1 presents a corrugated steel sheet from which tongues have been punched out; Fig. 2 shows the slab of the invention viewed from the side; this figure reveals the favourable size of the tongues; Fig. 3 illustrates the pressing of the steel sheet into the concrete; Fig. 4 presents a slab manufactured by the procedure of the invention. O M The slab is manufactured as follows. From a corrugated steel sheet 1 (Fig. 1 ) tongues 2 have been punched out. Their size and number depend on the intended use of the structure, on the load, span, type of profile, etc. and usually have to be determined by calculation. Their length is preferably the same as the thickness of the concrete slab because then the corrugated sheet will be positioned at the correct height upon the concrete slab when it is pressed on. Into a conventional, smooth mould made of plywood or another suit¬ able material is poured concrete mix 3 (Fig. 2), which is fur¬ nished, if necessary, with transverse steel reinforcement or with steel netting reinforcement. This mould may have sides by means of which the desired marginal shapes 4 are produced; it may be curved so that a pre-canber is obtained, and it may comprise apparatus 5 by the aid of which the sheet is pressed to be in contact with the bottom of the mould and by which the corrugated sheet is pressed to arcuate shape consistent with the pre-camber (Fig. 3)« The mould may also comprise apparatus by means of which on the slab are pro¬ duced concrete beams strengthening the . shearing capacity. Any method known in the art may be used to accelerate the curing of the concrete, advantageously also infra-red heating, because the mass to be heated is fairly minor. On accomplished curing of the concrete the mould is disassembled in conventional manner, the slab is inverted and conveyed into storage (Fig. 4).

Claims: Claims 1. The manufacturing of a compound structure consisting of a cor¬ rugated steel sheet (1 ) and a concrete slab (3), wherein the con¬ crete is first poured into a mould, characterized in that the steel sheet (1), provided by punching with tongues (2), is pressed into the concrete before its hardening, the length of the tongues having been selected consistent with the concrete thickness so that the steel sheet (1 ) assumes a position at the correct height with ref¬ erence to the bottom of the mould, carried by the points of the spikes. 2. Manufacturing procedure according to claim 1 , characterized in that the slab can be given, if needed, a pre-camber which is ap¬ propriate in view of load, shrinkage or equivalent, by simply pressing upon it with the aid of simple weights. O FI

Inventors: KOIVU TEUVO, KOIVU, TEUVO
Applicants: REDECON OY
Application year: 1983
Main classification: E04C2
IPC codes: B28B23, E04C2