PREFABRICATED LARGE PANEL FLOOR FORMWORK AND A METHOD OF SHUTTERING USING SUCH FORMWORK

Abstract: A formwork (1) is provided with a rocker structure (2) consisting of a vertically extending suspending post (2a) and horizontal supporting beams (2b and 2c) as well as frameworks (1a and 1b). Pivotable supporting arms (3) are provided at the ends of the frames (1a and 1b). These supporting arms can be pivoted between horizontal and vertical positions. The supporting arm (3) has a body (3a) of approximately triangular cross-section through which passes a threaded spindle (3c) fixable by means of a nut (3d). One end of the support arm has an articulated connection (3e) while the other end has an abutment post (3f). The floor construction (8) for the formwork is provided with suitable apertures (9 and 10) to allow the suspending arm (2a) to be passed through it and for access by a tool for the screwing and unscrewing of the nut (3d) from the spindle (3c) as well as the passage of the supporting arm (3) in its vertical position parallel with the suspending arm (2a) while the formwork is lowered through the floor (8).

Description: The invention concerns prefabricated large panel floor formwork and a method of shuttering using such formwork wherein the formwork contains metallic frameworks covered by metallic plates. About 20 to 40% of the load bearing portions of building structures are constituted by floor structures. Of all the load bearing structures, the finishing or making of such floor structures is the costliest, as is the amount of care demanded by them. Hence, several types of contructional solutions have been developed for making floor structures. One such group is represented by monolithic reinforced concrete floor structures prepared in situ. It is a peculiar property of such structures that a formwork provided with a supporting structure must be provided at the site of the construction for the floor or roof to be made. There are large-panel constructions known for preparing formworks which may be used repeatedly. Such solutions are known for instance from GB-A-1,469,325 (International Class E 04 G 11/46, inventor K.G.T.Burstedt) for supporting from below a bottom- ribbed floor; GB-A-1,457,136 (International Class E 04 G 11/48) disclosing a solution involving an adjustable supporting post, and USA-A-4,170,338 (international Class E 04 G 11/40) which describes a large span formwork with supporting platforms. It is a common characteristic of these large panel formworks utilised in situ for monolithic reinforced concrete floors that they are formed with supporting rods or supporting platforms, that they are disposed in a plane beneath the plane of the shuttered floor and bear on the previously made floor structure of the level below them. In order to assure the required rigidity, their constructional solution requires a great deal of material, their adjustment level by level is labour intensive, frequently special lifting gear is required for their displacement, their use requires higher technical skills and they are both costly and time-consuming. For the above reasons, the use of large-panel formworks has not become widespread and instead permanently remaining or retained formworks have begun to come to the forefront. An aim of the present invention is to eliminate the supporting posts or platforms of formworks as well as to obviate lifting gear when the formwork is to be repeatedly used at the same site, and to minimise the number of operations and the duration of operations of assembling and dismantling. The concept underlying the invention is the recognition that if the large formwork panel is provided with arms which can be folded back, and a suspending column that can be passed through the floor construction, then by means of a crane used in the building industry, the formwork may be simply transferred from the upper supporting level to the next supporting level. In accordance with the above aims of the invention, the prefabricated large-panel floor formwork according to the invention comprises metallic frameworks covered with metal sheets and provided with supporting arms which can be folded back or retracted and which in use are supported on the supports of the existing structure, and for its displacement, e.g. lifting or lowering by a crane, it is provided with a suspension column which passes through the floor/roof construction of the existing structure. A preferred feature of the invention consists in that its supporting arms and suspension column are connected to the formwork from above through the floor structure. The supporting arm is connected to the floor formwork by way of a supporting column, a supporting arm is hinge-connected to the supporting post ,a screw spindle is releasably connected to the formwork through the floor structure via the supporting arm, and the upper portion of the screw spindle is provided with a tabbed or tongued nut for adjusting and fixing the floor formwork, while the end of the support arm opposite to the hinge is provided with a supporting nose plate abutting against the floor structure. The suspending post or column is passed through the floor structure at the centre of gravity of the latter and beneath it is connected to supporting beams. The metallic frameworks covered with metal sheets are releasably connected together. The floor of the existing structure is provided with an aperture of conical shape to guide the lowering of the suspension post through it. The shuttering process according to the invention using the formwork according to the invention is characterised in that the supporting arms of the formwork are placed on the uppermost supports of the existing structure wth the aid of the suspending post or column passed through the centre of gravity of the floor formwork, then after building the floor structure provided with apertures for the suspension column, the support arms and a key wrench or spanner, the fixing nut placed on the threaded spindle on the support arms is released, the support arm is displaced to its vertical position, the floor formwork is lowered by means of lifting gear, e.g. a crane, beneath the just-built floor structure, expediently one metre below, whilst holding it at the suspending column or post, the support arm is then set to its horizontal position through the opening and with the aid of a spanner the tabbed or tongued nut is screwed back onto the screw spindle and the floor structure is lowered to the next support from above. The invention has appreciable advantages. One such advantage is that no special lifting gear is required for its displacement. Another advantage is that it consists of easily transportable and displaceable partial units. The assembly of the prefabricated units takes place on site within the operating range of the lifting crane. The formwork may be used repeatedly. The dismantling and re-assembly operations require only a little time and no special technical skill thanks to the releasable connections. A preferred embodiment of the invention will now be described, purely by way of example, with reference to the accompanying diagrammatic drawings wherein: Figure 1 is a perspective view of formwork according to the invention; Figures 2a and 2b show a rocker forming part of the formwork of the invention respectively in cross-section and longitudinal section and on an enlarged scale; Figures 3a and 3b illustrate the supporting arm forming part of the formwork of Figure 1 in its fixed position, respectively in cross-section and longitudinal section and on an enlarged scale, and Figure 4 is a longitudinal section illustrating two phases of the lowering of the formwork. Figure 1 illustrates a large-sized floor panel formwork 1. The formwork according to the invention is a large-sied floor panel formwork 1 corresponding to the area bounded by the modular grid lines of the building, that is to say to a floor area corresponding to one module or raster. The large sized panel consists of partial units which are readily transportable by road or rail. The manufacture of the partial units takes place in factories, i.e. the units are pre­ fabricated, using hot-rolled or cold-rolled steel profiles and thin sheets. The assembly of the partial units into a single unit takes place on site within the operating range of a lifting crane. The partial unit are made in two variants, namely edge-units 1a and intermediate units 1b. The frame of the partial form units 1a and 1b is made up of frames 1c and 1d provided with secondary ribs and made from steel sections. These sections are then covered with steel sheeting 1e. The partial units 1a and 1b are connected together by screwing the frames together. A rocker 2 consisting of supporting beams 2b and 2c and a suspension post 2a assure the appropriate transverse rigidity of the screwed -­ together frames 1c and 1d provided with secondary beams. The suspension post 2a extends through the centre of gravity of the intermediate partial unit 1b perpendicularly to the plane of the formwork 1. The supporting ends of the frames 1c, 1d provided with secondary beams making up the edge and intermediate partial units 1a and 1b are provided with supporting arms 3 which can be swung in and out. This will be described and explained below. Figure 3 shows that the supporting arms 3 each have a body portion 3a supported on supports 5 of the previously made building structure. More particularly, as shown in Figure 3, each support arm body 3a is connected to the frames 1c, 1d by way of a supporting post 3b, as well as a threaded spindle 3c and tabbed nut 3d. One end of the supporting arm body 3a is connected to the supporting post 3b by way of an articulated or hinged connection including a pin 3e. The opposite end is provided with a nose plate 3f. The formwork 1 is lifted to the uppermost floor level by a crane provided on site where the arms 3a are seated on the supports 5 of the building's framework and they take over the bearing of the load of the formwork, the weight of the floor that will be placed on the formwork and other possible assembly loads. After lifting the formwork 1 into place the lifting rope of the crane can be released from the suspending post 2a and the crane can carry out the lifting of the next formwork 1. By rotating the tabbed nut 3d of the threaded spindle 3c the support and exact adjustment of the plane of the formwork 1 may be readily be carried out. Between the elements 3b and 3c of the support arms 3a passing through the floor inserts 6 made of a synthetic resin foam are disposed to block apertures provided for enabling these elements to be threaded through when the forms are stripped. Reverting to Figure 2 which illustrates the rocker 2, made up of the suspending post 2a and the supporting beams 2b and 2c, the latter are disposed beneath the floor 1 and support the floor 1 during lifting. Figure 3 illustrates the support arm in its fixed position while Figure 4 illustrates the operation of lowering the formwork 1. After preparing the uppermost floor level the lifting hook at the end of the rope of the crane is passed through the lifting eye of the suspending post 2a and the rope is somewhat tensioned while the tabbed nuts 3d fixing the support arms 3a are unscrewed and the support arms 3a are brought into the position for lowering. After separation, the formwork 1 can be lowered by the crane rope to a plane approximately 100 cm below the plane of the reinforced concrete floor that has just been prepared; then the upright support arms 3 are turned to a horizontal position (see the broken lines in Figure 4) and the tabbed nuts 3 are screwed back to the threaded spindle 3c by way of a hooked tubular spanner 7 passing through an aperture 10 in the reinforced concrete floor slab 8. The slab 8 is also provided with a frusto-­ conical aperture 9 for guiding the threading through it of the suspending post 2a. Thereafter the crane can lower the formwork 1 to the supports 5 of the next level where the support arms 1 are once more seated and the operations may be continued in accordance with the description given above. The formwork 1 is dimensioned to match the modular grid of the building and is thus suitable for shuttering the floor area bounded by the supports 5. The rocker 2 serves for suspending and displacing the floor formwork and its suspending post 2a is screw-connected to the supporting beams 2b and 2c. The framework 1 bears via its support arm 3 on the supports 5 of the existing building. The accurate adjustment of the formwork 1 takes place via the threaded spindle 3c and the tabbed nut 3d. The articulated connection 3e of the support arm 3a makes it possible for the floor formwork 1 to be removed or lowered. The support arm 3a is held in a fixed position by way of the threaded spindle 3c and the tabbed nut 3d as well as the hinge made up of the supporting posts 3b and the pin 3e. Although the formwork described above is primarily designed for shuttering floor elements, it may also be used for shuttering other constructions.

Claims: 1. Formwork for prefabricated large-sized panels comprising metallic frameworks covered by metallic sheeting characterised in that the formwork is provided with supporting arms (3) adapted to bear the supports (5) of an existing structure, which support arms (3) may be bent or swung back, and in that it is provided with a suspending post (2a) passing through the floor structure (8) of the existing building for the displacement of the formwork, e.g. for lifting or lowering the formwork by a crane. 2. Formwork according to claim 1 characterised in that its supporting arms (3) and suspending posts (2a) are connected in use to the formwork (1) from above and through the floor structure (8). 3. Formwork according to claim 1 or 2, characterised in that each supporting arm (3) is connected to the formwork (1) by way of a supporting column (3b), the supporting column (3b) is connected to the support arm body (3a) by way of an articulated connection (3e), the support arm body (3a) is releasably connected to the formwork (1) by a threaded spindle (3c) passing through the floor structure (8) the upper part of the threaded spindle (3c) is provided with a tabbed nut (3d) for adjusting and fixing the formwork (1), and the end of the supporting arm body (3a) opposite the articulated connected (3e) is provided with a nose plate (3f) abutting against the floor structure (8). 4. Formwork according to any preceding claim, characterised in that the suspending post (2a) is passed through the formwork (1) at the centre of gravity of the latter, and is connected to beams (2b, 2c) supporting the formwork (1) from below. 5. Formwork according to any preceding claim, characterised in that the metallic frameworks (1c, 1d) covered with metallic sheeting are releasably connected together. 6. Formwork according to any preceding claim, characterised in that the floor structure (8) of the existing building is provided with an aperture for the passing through of the suspending column (2a) which aperture has conical guiding edges (9). 7. A process for shuttering by utilising prefabricated large sized panel formwork according to any preceding claim, characterised in that the supporting arms (3) of the formwork (1) are placed on the uppermost supports (5) of the existing building structure with the aid of a suspending column (2a) passed through the centre of gravity of the formwork (1), and after building the floor structure (8) provided with apertures for the suspending column (2a), the support arm (3) and a spanner or like tool, the tabbed nut (3d) provided on the threaded spindle on the support arm (3) is released, the supporting arm body is set to a vertical position, the formwork (1) is lowered by lifting gear, e.g. a crane, by holding it at its suspending column (2a) to a level beneath the finished floor structure (8), expediently one metre below the plane of the latter, through the aperture (10) the support arm (3) is set to a horizontal position and with the aid of a spanner (7) or like tool, the tabbed nut (3d) is screwed back on the threaded spindle (3c), and the formwork (1) is lowered to the support (5) which is the next successive one from above.

Inventors: ANDREANSZKY, IMRE, GERGELY, ISTVAN, MEHES, FERENC, Andreánszky, Imre, Gergely, István, Méhes, Ferenc
Applicants: KULTURINVEST FOVALLALKOZASI BETETI TARSULAS
Application year: 1985
Main classification: E04G17
IPC codes: E04G17