EP0213242B1

EP0213242B1 - Prefabricated large panel floor formwork and a method of shuttering using such formwork

Info

Publication number: EP0213242B1
Application number: EP19850305712
Authority: EP
Inventors: Imre Andreánszky; István Gergely; Ferenc Méhes
Original assignee: Kulturinvest Fovallalkozasi Beteti Tarsulas
Current assignee: Kulturinvest Fovallalkozasi Beteti Tarsulas
Priority date: 1985-08-12
Filing date: 1985-08-12
Publication date: 1989-11-23
Also published as: EP0213242A1; DE3574405D1

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 costli- est, as is the amount of care demanded by them. Hence, several types of constructional 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 US-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.
From GB-A-428 208 it is known to provide formwork comprising metallic frames covered by metallic sheeting and providing with swingable arms capable of bearing against supports of an existing building structure. This known mechanism described does not permit the formwork to be erected or dismantled from above the floor under construction, nor can the formwork be assembled together at the same time as the assembly of the structural framework of the building.
US-A-2 060 046 describes a formwork provided with a suspension post passing through the floor structure for enabling the formwork to be displaced. But the described formwork is supported by a multiplicity of costly supports; and the formwork for a new floor must be assembled from a previously made floor above the floor in question, whilst the suspension post requires two higher floors to pre- exist.
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.
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 as 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 formwork according to the invention starts from the disclosure of GB-A-428 208 and comprises metallic frame members covered by metallic sheeting, supporting beams for supporting the formwork from below, pivotally extendable and retractable supporting arms connected to said frame members and adapted to bear on supports of an existing floor structure, characterized in that a suspending post is connected to a said supporting beam and extends through the centre of gravity of said floor structure for enabling the displacement of the formwork e.g. lifting or lowering by a crane, to be effected, and wherein each said supporting arm consists of a supporting arm body extending fully above the said floor structure, a supporting column rigidly connected to said metallic frame members and connected to the supporting arm body by way of an articulated connection; in that the supporting arm body is releasably connected to the metallic frame members by a threaded spindle passing through the floor structure, the upper part of the threaded spindle being provided with a tabbed nut for adjusting and fixing the formwork; in that the end of the supporting arm body remote from the articulated connection is provided with a nose plate abutting against the floor structure; and in that the suspending post is passed through the formwork at the centre of gravity of the latter, and is connected to said supporting beams.
The metallic frameworks covered with metal sheets may be releasably connected together. The floor of the existing structure may be provided with an aperture of frusto-conical shape to guide the lowering of the suspension post through it.
The shuttering process according to the invention using the formwork set forth above is characterised in that the supporting arms of the formwork are placed on the uppermost supports of the existing building structure with the aid of a suspending post passed through the centre of gravity of the formwork, and after building the floor structure provided with apertures for the suspending post, the supporting arm is released by means of a spanner or like tool engaging the tabbed nut provided on the threaded spindle, the supporting arm body is swung to a vertical position, the formwork is lowered by lifting gear, e.g. a crane, by holding it at its suspending post to a level beneath the finished floor structure through an aperture, the supporting arm is then swung to a horizontal position and with the aid of said spanner or like tool, the tabbed nut is screwed back on the threaded spindle, and the formwork is lowered to the support which is the next successive one from above.
The formwork according to 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 short 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 corresponding to the area bounded by the modular grid lines of a building, that is to say to a floor area corresponding to one module.
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 prefabricated, 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 units are made in two variants, namely edge-units 1a and intermediate units 1b. The partial form units 1 a and 1 b are made up of frames 1 c and 1 d provided with secondary ribs and made from steel sections. These sections are then covered with steel sheeting 1e. The partial units 1a and 1 b are connected together by screwing the frames together. A rocker consisting of supporting beams 2b and 2c and a suspension post 2a assure the appropriate transverse rigidity of the screwed - together frames 1 c, 1 d. The suspension post 2a extends through the centre of gravity of the intermediate partial unit 1 perpendicularly to the plane of the formwork 1.
The supporting ends of the frames 1 c, 1 d provided with secondary beams making up the edge and intermediate partial units 1a and 1 are provided with supporting arms 3 which can be swung in and out. This will be described and explaned below.
Figures 3a and 3b show 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 figures 3a and 3b, 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 trheaded spindle 3c the support and exact adjustment of the plane of the formworki may be readily be carried out. Between the post 3b and spindle 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, made up of the suspending post 2a and the supporting beams 2b and 2c, the latter are disposed beneath the formwork 1 and support the floor during lifting.
Figures 3a and 3b illustrate 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 3a are turned to the position shown in broken lines in figure 4 and the tabbed nuts 3d are screwed back to the threaded spindle 3c by way of a 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 through which the suspending post 2a may be threaded.
Thereafter the crane can lower the formwork 1 to the supports 5 of the next level where the support arms 3a 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 serves for suspending and displacing the floor formwork and its suspending post 2a is screw-connected to the supporting beams 2b and 2c. The formwork 1 bears via its support arm 3a on the supports 5 of the existing building.
The accurate adjustment of the formwork 1 takes place via the threated 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 assembly for prefabricated large-sized panels, comprising metallic frame members (1 c, 1d) covered by metallic sheeting (1e), supporting beams (2b, 2c) for supporting the formwork (1) from below, pivotally extendable and retractable supporting arms (3) connected to said frame members (1c, 1d) and adapted to bear on supports (5) of an existing floor structure (8), characterized in that a suspending post (2a) is connected to a said supporting beam (2b) and extends through the centre of gravity of said floor structure (8) for enabling the displacement of the formwork (1), e.g. lifting or lowering by a crane, to be effected, and wherein each said supporting arm (3) consists of a supporting arm body (3a) extending fully above the said floor structure (8), a supporting column (3b) rigidly connected to said metallic frame mebers (1 c, 1 d) and connected to the supporting arm body (3a) by way of an articulated connection (3e); in that the supporting arm body (3a) is releasably connected to the metallic frame mebers (1c, 1d) by a threaded spindle (3c) passing through the floor structure (8), the upper part of the threaded spindle (3c) being provided with a tabbed nut (3d) for adjusting and fixing the formwork (1); in that the end of the supporting arm body (3a) remote from the articulated connection (3e) is provided with a nose plate (3f) abutting against the floor structure (8); and in that the suspending post (2a) is passed through the formwork (1) at the centre of gravity of the latter, and is connected to said supporting beams (2b, 2c).

2. Formwork according to claim 1, characterised in that the floor structure (8) of the existing building is provided with an aperture for the passing through of the suspending post (2a), which aperture has frusto-conical guiding edges (9).

3. A process for shuttering by utilising prefabricated large-sized panel formwork according to claim 1, 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 post (2a) passed through the centre of gravity of the formwork (1), and after building the floor structure (8) provided with apertures (9) for the suspending post (2a), the supporting arm (3) is released by means of a spanner or like tool (7) engaging the tabbed nut (3d) provided on the threaded spindle (3c), the supporting arm body (3a) is swung to a vertical position, the formwork (1) is lowered by lifting gear, e.g. a crane, by holding it at its suspending post (2a) to a level beneath the finished floor structure (8) through a said aperture (9), the supporting arm (3) is then swung to a horizontal position and with the aid of a said 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.