A COMPOSITE SLAB ELEMENT

Abstract: A composite slab element comprised of a cast portion (1), e.g. concrete, cast reinforcement (2), e.g. a steel net, possible intermediate purlins (5) and joists (8). A single joist has at least two parallel ranged joist elements (8), between which a metal sheeting (4) is placed, whereat the edge of the metal sheeting extends from the joist element to the concrete and the metal sheeting functions both as a composite and a reinforcement part.

Description: A COMPOSITE SLAB ELEMENT The invention relates to an industrially produced composite slab element comprised of a metal sheeting of special con¬ struction with the function of a composite and reinforcement part, on both sides of which joists are pressed forming together the element framework; a concrete slab portion; a reinforcement portion in the sealing compound, e.g. a steel net; and intermediate purlins. Slab elements are used mainly as base, intermediate and upper floors in detached houses, terraced houses, small apartment ..ouses and indutrial halls. With the concrete side mounted downward, the element is also well adaptable as a s.c. Radon preventing base floor. Among load-bearing floor constructions made by known techno¬ logy hollow-core concrete slabs and TT slabs and floor structures of different composite slab constructions can be mentioned, the FI publication prints 66229 and 60752 as -examples. As their disadvantages can be stated a.o. that the concrete slabs are quite heavy and not applicable to timber-framed buildings due to heavy weight, transportation and handling of concrete slabs at site is complicated and expensive normally, present floor structures of composite slab con¬ structions are cast under site conditions, where either flat or profiled sheet metal must be used as casting base/mould usually, the effective span of present floor structures of composite slab construction does not exceed 6 metres frame elements of mere wood, to which composite parts are fixed for the sealing compound, must in most cases be straightened at site, since wood tends to twist and warp. Possible pre-elevation must be done at site using a s.c. Homegon composite slab and a corresponding method, the slab becomes heavy, since the concrete in the profiled portion does not function effetively, and making thermal and sound insulation, heating, plumbing, air conditioning and electric installations are complicated and expensive. The object of this invention is to remove the above disadvant¬ ages and to produce a composite slab element, where a light and strong construction is achieved by joists pressed on both sides of a metal sheeting of special design and by a concrete portion engaged to the construction by said metal sheeting, in which slab construction the joists and sheeting take over the tension load and the compression load. The composite slab element according to the invention is characterized in what is presented in the patent claims. The advantage of the invention is, in the first place, the simplification of manufacture compared with previously known technology. It is also an advantage that a significantly longer effective span and a lighter construction are achieved, due to which the element transportation and handling costs are reduced. A further significant advantage is also the space left between the joists, allowing heating, plumbing, air con¬ ditioning and electric installations as well as sufficient sound and thermal insulation. Throug pre-stamped openings in the sheeting transverse heating, plumbing, air conditioning and electric installations can be done. The ease of making stair and other openings can also be considered an advantage as well as the soffit of joists functioning as studs and direct to which different roofing materials can be fixed by nails. In addition, a significant advantage is reached in fire protection, since the location of the composite and reinforce¬ ment metal sheeting is between fire-retardant wooden parts. Balkonies, bay windows and other corbels are very easy to make. To prevent heat conduction at the through hole, sheeting is removed from a distance of ab. 50 mm In the following the invention is disclosed with reference to the enclosed drawing where, Fig. 1 shows the slab element in the diagonal. Fig. 2 shows a cross-section of the slab element. Fig. 3 shows a lengthwise section of the slab element. Fig. 4 shows the slab element turned upside down. Fig. 5 shows a load-bearing joist as per the invention. Figure 1 is a composite slab element as per the invention comprising a concrete slab portion 1 including a steel net 2 as reinforcement of the construction. Under the concrete slab, at a distance from each other, there are joists, both of them made of two wooden joists 8, in between of which a metal sheeting 4 is pressed. The metal sheeting has prongs 7 on both sides, the sheeting reaching to the lower edge of joists 8 and the upper edge of sheeting 4 protruding from between joists 8 to the concrete. The continuous sheeting 4 in the element attaches the wooden joists to the concrete. Most conveniently, the element has also an intermediate purlin 5 transversal between joists 8. The element is manufactured so that in the first stage the cut-to-size joists 8 and sheeting 4 are pressed together. In the second stage the joists are connected for a certain spacing and the intermediate purlins 5 fixed in place. In the third stage sealing compound 1 is casted as a layer of appr. 50 mm into a mould with demountable edge and levelled by vibration. A steel net 2 is then mounted on the sealing com¬ pound, whereafter the joist frame with intermediate purlins is put 1 on reinformcement 2 in the sealing compound, vibrated and pressed in the concrete till the sheeting has sunk 25 mm and intermediate purlins ab. 2 - 3 mm into the concrete. The element is then left to cure and to become solid. Figure 2 shows the element from the rear and partly sectioned and figure 3 shows a side view of the same element, partly sectioned. In sheeting 4 openings 6 are made apart from each other, through which transversal plumbings and wirings are possible. In figure 4 the element is upside down and in this position applicable for installation as a base floor and, for instance as an embodiment, to prevent Radon hazards due to its dense structure. Figure 5 shows an example of a joist applicable in conjunction with the invention. A great bearing is capacity is reached by making the joist of several elements using two sheetings 4 and 14. The upper part 13 of sheeting 4 reaches into concrete 1. Joist elements 8 and 9 of joist upper part are joined together by sheeting 4, whereat plywood web 10 is also engaged with the upper part. The joist lower part is assembled by means of sheeting 14, into which elements 11 and 12 and web 10 are pressed. Most conveniently, the elements 8,9,11 and 12 are of wood. It is not the intention to restrict the invention to the above presented embodiment examples only, but many modifications are possible within the limits of the patent claims. As framework different materials can be mentioned, such as plastic, glass fibre and different board structures as well as production of the element without intermediate purlins.

Claims: PATENT CLAIMS 1. A composite slab element comprised of a cast portion (1), e.g. concrete, a cast reinforcement (2), e.g. a steel net, joists (8), (9,10,11,12) and possible intermediate purlins (5) characterized in that a single joist has at least two parallel ranged joist elements (8), (8,9), between which a metal sheet¬ ing (4) is placed, whereat the edge (13) of the metal sheeting extends from the joist element (8), (8,9) to the concrete (1) and the metal sheeting functions both as a composite and a reinforcement part. 2. A composite slab element according to patent claim 1 characterized in that the joint between joist elements, concrete and metal sheeting is produced by means of prongs (7) stamped out from the sheeting. 3. A composite slab element according to patent claims 1 and 2 characterized in that the metal sheeting extends from concrete (1) to the lower edge of joist element (8). 4. A composite slab element according to patent claims 1 and 2 characterized in that the joist is comprised of several joist elements (8,9,10,11,12) and several element-combining sheet¬ ings (4,14), whereat the uppermost sheeting (4), viewed from the joist applicational position, extends to the concrete.

Inventors: WEDERHORN YRJOE KALEVI, WEDERHORN, YRJOE, KALEVI
Applicants: WEDERHORN YRJOE KALEVI, WEDERHORN, YRJOE, KALEVI
Application year: 1996
Main classification: E04B5
IPC codes: E04B5, E04C3