EP0039931B1 - Permanent form element as part of a concrete floor, method of producing a concrete slab for this formwork and anchoring device therefor - Google Patents

Abstract

1. Permanent formwork for a concrete floor or ceiling slab comprising at least two mutually adjoining prefabricated concrete plate elements (1, 2), wherein at least one base portion (14, 34, 35, 42, 43, 47, 51, 52) of an anchor (10, 31) is anchored in the concrete of each of the adjacent plate elements (1, 2, 32, 33) in the edge regions of said plate elements that adjoin the respective abutting edges thereof, said base portion being force-lockingly connected to a head portion (16, 36, 44, 53) which projects out of the top (15) of the plate and which, at a spacing therefrom, has a contact surface for a connecting member (11, 38) for connecting two adjacent anchors (10, 31), characterised in that said anchors (10, 31) are fitted in the edge region of two adjacent plate elements (1, 2, 32, 33) which are rigid for assembly thereof, in such a way that the contact surfaces of the head portions (16, 36, 44, 53) are disposed at a predetermined height above the underside of the respective plate elements, so that the connecting member (11, 38) secures the undersides of adjacent plate elements in an aligned condition in a vertical respect and is clamped against the contact surfaces of two adjacent anchors (10, 31) and the transverse forces which occur when clamping the connecting member and when concreting the slab (1) can be transmitted by way of the two anchors (10, 31) and the associated connecting member (11, 38).

Description

The invention relates to a permanent formwork for a concrete ceiling, consisting of at least two adjacent, prefabricated, assembly-resistant plate elements made of concrete according to the preamble of claim 1. Furthermore, it relates to a method for producing a plate element and an anchor for the formwork.

Prefabricated plate elements are placed in a central location in a size suitable for transport, e.g. B. in dimensions of 2 m x 5.20 m or 1 m x 5.20 m. As a rule, they are 4 cm thick and, in addition to the static reinforcement, also contain stiffening reinforcement in the form of lattice girders protruding from the slab. The panels are brought to the construction site and form permanent formwork for the production of ceilings. For this purpose, such slab elements are placed next to each other on the retaining walls, where necessary, assembly supports are attached and in-situ concrete is poured at the required height.

Especially with large assembly support widths, different deflections can occur between adjacent panels, which lead to a visible step on the underside of the finished ceiling. To avoid this, additional assembly supports are generally installed.

The provision of additional assembly support, which can only be removed again when the in-situ concrete of the ceiling has hardened, requires a substantial amount of effort.

From US-A-62844024, permanent formwork for a concrete slab of a bridge serving as a carriageway has become known, in which the supporting beams are bridged by lattice girders and prefabricated concrete elements made of concrete are fastened to the lower chords of the lattice girders by means of hooks. The plate elements are designed on the abutting edges in the form of a tongue and groove connection in order to align the underside of adjacent plate elements. Furthermore, anchors for non-positively receiving a connecting element are fastened in edge regions of these plate elements adjoining the abutting edges of adjacent plate elements, which are anchored with their foot part in the concrete of the plate element, protrude like bolts from the top side of the plate and have a flattened head at a distance from it. The connecting link is designed in the form of a tab with two slots provided at a distance from the bolt-shaped projections of the anchors and is pushed together after adjacent plate elements have been pushed together, ie. H. after making the tongue and groove connection pushed onto the bolt-shaped projections. It prevents the distance between the adjacent bolt-shaped projections from increasing and the tongue and groove connection from being released. The shear force is transmitted via the tongue and groove connection. The tab-shaped connecting member only takes on the task of locking in connection with the bolt-shaped projections.

This construction requires specially and precisely manufactured plate elements. So that the plate elements of the plate level can be pushed together to produce the tongue and groove connection, they must be correspondingly light, i. H. be small and thin. In one exemplary embodiment, the area dimension is specified as 0.9 m × 0.9 m. Since the plate elements are only attached to the stiffening lattice girders at the construction site, the construction is also labor-intensive.

LU-A-67 357 has made known a building construction from prefabricated parts, in which massive ceiling elements are non-positively connected by coupling devices at the joints. For this purpose, recesses are provided in the area of the abutting edges of the finished parts, into each of which wedge slats of one and the other plate protrude, which can be non-positively connected by wedges. The connection is designed in such a way that adjacent finished parts can be aligned during assembly, thus making it possible to compensate for construction tolerances.

In this construction, the ceiling is formed from solid prefabricated panels, i.e. H. the finished parts do not serve as formwork for a concrete ceiling, so that there are corresponding transport problems and a labor-intensive adjustment process is required for the precise alignment of these finished parts.

The object of the invention is to form a permanent formwork of the type mentioned in the preamble with prefabricated, large-area, rigid panel elements without special training of the abutting surfaces of the plate elements is required. By clamping the connecting link to the anchors of adjacent plate elements protruding from the top of the plate, the lower edges should be able to be automatically aligned, so that observation of the underside of the ceiling and a special adjustment process are not necessary.

This object is achieved by means of a formwork with the characterizing features of claim 1. Advantageous embodiments of the invention can be found in subclaims 2 to 11. A method for producing a plate element for such formwork is characterized by claim 12. The formation of an anchor for such formwork is characterized by claims 13 for such formwork is characterized by claims 13 to 15.

The plate element for the invention In the area of the abutting edge adjoining the adjacent plate element, the formwork has at least one anchor which can be non-positively connected to the corresponding anchor of the adjacent plate element by means of a connecting member, so that here a connection point is created in a simple manner which is capable of transverse forces to transfer from one plate element to the other plate element and thus to prevent a different deflection of the plate elements at this point.

The positive connection must take into account on the one hand the fact that the thickness dimensions of the two plates in the area of the connection point are somewhat different for manufacturing reasons and it must also be possible to transmit transverse forces acting both upwards and downwards. The latter requirement takes into account the fact that it cannot be determined from the start to which of the plate elements a load is initially applied.

If necessary, more than one non-positive connection points formed by anchors and a connecting element can be provided along the butt joint of two adjacent plate elements. So that these can be realized by uniform plate elements, the position of the armature is preferably chosen to be axially symmetrical.

• Figur 1 schematisch die Anordnung einiger Plattenelemente, die die bleibenden Schalung für eine Decke bilden,
• Figur 2 den Schnitt 11-11 von Fig. 1
• Figur 3 den Schnitt 111-111 von Fig. 2
• Figur 4 einen der Fig. 2 entsprechenden Schnitt eines dritten Ausführungsbeispiels
• Figur 5 den Schnitt V-V von Fig. 4
• Figur 6 eine perspektivische Ansicht des bei der Ausführungsform nach den Fig. 6 und 7 eingesetzten Ankers
• Figuren 7 bis 10 weitere perspektivische Ansichten von Ankern für kraftschlüssige Verbindung.

The invention is explained in more detail by means of exemplary embodiments with reference to 11 figures. Show it :

• FIG. 1 shows schematically the arrangement of some plate elements that form the permanent formwork for a ceiling,
• 2 shows the section 11-11 of Fig. 1st
• 3 shows the section 111-111 of FIG. 2nd
• 4 shows a section corresponding to FIG. 2 of a third exemplary embodiment
• 5 shows the section VV of Fig. 4th
• 6 shows a perspective view of the anchor used in the embodiment according to FIGS. 6 and 7
• Figures 7 to 10 further perspective views of anchors for non-positive connection.

Fig. 1 shows a top view of three adjacent plate elements 1, 2 and 3 made of concrete, which are placed on retaining walls 5, 6 and 7 and form the permanent formwork for a concrete floor. In addition to a static reinforcement (not shown) made of reinforcing steel mesh and reinforcing bars for the finished ceiling, each plate element also contains stiffening reinforcement, preferably made of lattice girders, which are indicated by dash-dotted lines 8 in the plate element 1. Each line should represent a lattice girder.

In the region of the longitudinal edge (abutting edge) adjoining the adjacent plate element, each plate element carries at least one anchor 10 for the non-positive connection of a connecting member 11 (see FIG. 2) between the two anchors 10. Further non-positive connections can be made along the joint between adjacent plate elements, for example be provided at the points marked by dashed lines 12 and 13.

As shown in FIGS. 2 and 3, the anchors consist of a foot part, which in the present case is designed as a plate 14 and anchored in the concrete of the plate element 1 or 2, and a head part which is non-positively connected to the foot part and which consists of the plate top 15 protrudes and is formed in the embodiment by a closed bracket 16. To produce the adhesion, the U-shaped bracket in this case is welded to the plate 14 with its two legs.

In order to enable a transfer of transverse forces of the plate element 1 to the plate element 2 or vice versa through the connecting member 11, the connecting member 11 is wedged both on the plate element 1 and on the plate element 2. For this purpose, as shown in FIG. 3, there are two wedges 17 and 18, which are preferably made of wood. The wedges make it easy to compensate for differences in the thickness of the plate elements 1 and 2 in the region of the connection point which are caused by the production.

To manufacture such prefabricated plate elements, the anchors 10 are first inserted into the form of these elements at the intended locations and fixed relative to the formwork. Since the underside of the anchors 10 is to be aligned with the underside of the plate elements, these elements are therefore simply placed on the floor of the formwork at the intended location and the brackets 16 are fixed to the formwork in the area later protruding from the plate surface via a suitable clamping device . The remaining reinforcement is then introduced and the plate element is manufactured as usual. After laying such plate elements on the construction site (see Fig. 1), the connecting members 11 are introduced and clamped by means of the wedges 17 and 18. After the connection member 11 has been fixed by the wedges, the two plate elements are non-positively connected at this point and when one element bends, such a strong transverse force is exerted on the adjacent element that it bends in the area of the abutting edge in the same way. This avoids paragraphs on the butt joints of the panel elements on the underside of the finished ceiling.

The connecting member 11 is designed in the present case as a round metal rod. Of course, other cross-sections can be used for the connecting link and the upper region of the bracket 16 can be adapted to these cross-sectional shapes.

Since the foot part 14 of the armature 10 in the illustrated embodiment also forms the underside of the plate element at this point, it should be formed with a non-corroding surface. Suitable for this galvanized steel sheet, for example.

In the illustrated embodiment, the bracket 16 of the armature 10 is arranged directly on the abutting edge 19 of the respective plate element 1 or 2. This arrangement is advantageous with regard to the transfer of lateral force from one plate to the other. So that the problems caused by tolerances during manufacture and during installation can be solved, the clear width between the legs of the U-shaped bracket 16 is a multiple of the diameter or the width dimension of the connecting member 11. The clear width should be so large that taking into account the maximum permissible tolerances during manufacture and during installation, the connecting member 11 can still be pushed and wedged through the two adjacent brackets 16 of the adjacent plate elements 1 and 2 without difficulty.

Since the two brackets 16 are closely adjacent to one another, their lower edges 20 are brought to the same height by means of the connecting member 11 if the connecting member 11 runs only somewhat parallel to the underside of the plate. Is therefore ensured in the manufacture and installation of the armature 10 that the distance 21 between the lower edge of the horizontal bracket section and the lower surface of the associated plate member always has the same value, then the bracket 16 by means of the alignment of the lower edges 20 Link 11 also aligned the lower adjacent edges of the adjacent plate elements 1a and 2a, i. H. there is no observation of the underside of the ceiling when the connecting member is clamped.

According to a development of the invention, this idea is further developed in the exemplary embodiments described below. Here in each case the head part of the anchor protruding from the top of the plate has a support surface for the connecting member, which in the case of each anchor in the installed state lies at the same predetermined height above the underside of the plate element in question and runs parallel to the underside. Therefore, if the adjacent support surfaces of two adjacent anchors are brought to the same level by clamping the connecting member on this support surface, the undersides of the two adjacent plate elements in the region of the two anchors are also forced to the same level, i. G. the two adjacent lower edges adjoin one another without a difference in height and are held in this position by the shear force-transmitting anchors even when under load.

The anchor 31 used in the second exemplary embodiment according to FIGS. 4 and 5 and shown in perspective in FIG. 6 contains a foot part made of at least two anchoring brackets 34 and 35 embedded in the concrete of the plate elements 32 and 33. The anchoring brackets here are also U-shaped and welded to a hexagon cylinder piece 36, which can also be a tube, the upper end face 37 of which protrudes from the upper side of the plate is designed as a contact surface for the connecting member 38. The connecting member 38 is clamped on the bearing surface by means of a screw connection from a threaded bore 39 in the cylinder piece 36 and a screw 40. So that a good alignment of the contact surfaces 37 of the two adjacent anchors 31 is possible via the connecting member 38, the connecting member is tab-shaped, i.e. H. formed with a mating surface matching the discharge surface 37. By clamping the connecting member by means of the two screws 40, the bearing surfaces 37 and thus the lower edges of the adjacent plate elements 32 and 33 are brought to the same height. As FIG. 6 shows, the connecting member 38 has elongated holes 41 in order to be able to compensate for the inaccuracies caused by the manufacture and laying of the plate elements.

In the embodiment shown in FIGS. 4 and 5, an anchoring bracket, namely the anchoring bracket 34, is provided on the underside of the plate and an anchoring bow, namely anchoring bracket 35, is provided on the top of the plate. The two brackets take into account the fact that the anchor must be able to transmit transverse forces in both directions. It is also possible to provide only a single anchor bracket if it has a sufficient extent. In this case, the anchoring bracket must be arranged approximately in the middle between the underside of the panel and the top of the panel.

The anchor shown in Fig. 7 is characterized by particularly simple manufacture. The foot part is also formed here by anchoring brackets 42 and 43, which, however, are V-shaped here, that is to say they each have only a single bending point. The brackets are welded at a suitable distance to a threaded bolt 44 onto which a nut (not visible in the illustration according to FIG. 7) is screwed, which optionally forms the bearing surface for the connecting member 38 with the interposition of a washer. The tab-shaped connecting member 38 can be clamped onto the support surface by means of a further nut 45. If the threaded bolt 44 has a screw head at the lower end, then it is expedient to provide spacers 46 on the lower anchoring bracket 42, which ensure that the anchor assumes the correct position on a flat formwork base without special measures. It should also be mentioned that when concreting the plate element, the thread is preferably covered by a plastic cap.

The anchor of FIG. 8 differs from that of FIG. 7 in that the lower anchor bracket 47 is U-shaped.

In the embodiments according to FIGS. 9 and 10, the foot part of the anchor is made of one the abutting edge of the plate element arranged, formed by claws 50 anchored in the concrete sheet 51 or 52. The plate 52 is bent inwards at both ends in order to ensure an even better anchoring in the concrete. The outside of the sheet metal strips 51 and 52, which is not visible in FIGS. 9 and 10, lies in the same plane as the surface of the abutting edge of the associated plate element. The angled ends of the sheet 52 are countersunk in the associated plate element. In the last described embodiments, a threaded bolt 53 is also provided as the head part.

As already described with reference to the embodiment shown in FIGS. 4 and 5, the lower edges of the plate elements are forcibly aligned by bringing the contact surfaces of the adjacent anchors to the same level by clamping the connecting member. With regard to this effect, the smaller the distance between the adjacent contact surfaces, the more favorable it is. H. is the distance between the head parts of the two anchors. The embodiments shown in FIGS. 9 and 10 are therefore also more suitable in terms of orientation than those in FIGS. 7 and 8 embodiments shown. However, you can also the distance between the contact surfaces, d. H. between the threaded bolts 44 adjacent anchors, by welding the threaded bolts not outside the anchoring bracket but outside the same. This position is indicated in dashed lines in Fig. 8 and designated 44 '.

Claims (15)

1. Permanent formwork for a concrete floor or ceiling slab comprising at least two mutually adjoining prefabricated concrete plate elements (1, 2), wherein at least one base portion (14, 34, 35, 42, 43, 47, 51, 52) of an anchor (10, 31) is anchored in the concrete of each of the adjacent plate elements (1, 2, 32, 33) in the edge regions of said plate elements that adjoin the respective abutting edges thereof, said base portion being force-lockingly connected to a head portion (16, 36, 44, 53) which projects out of the top (15) of the plate and which, at a spacing therefrom, has a contact surface for a connecting member (11, 38) for connecting two adjacent anchors (10, 31), characterised in that said anchors (10, 31) are fitted in the edge region of two adjacent plate elements (1, 2, 32, 33) which are rigid for assembly thereof, in such a way that the contact surfaces of the head portions (16, 36, 44, 53) are disposed at a predetermined height above the underside of the respective plate elements, so that the connecting member (11, 38) secures the undersides of adjacent plate elements in an aligned condition in a vertical respect and is clamped against the contact surfaces of two adjacent anchors (10, 31) and the transverse forces which occur when clamping the connecting member and when concreting the slab (1) can be transmitted by way of the two anchors (10, 31) and the associated connecting member (11, 38).

2. Formwork according to claim 1, characterised in that the anchor (10) is formed from a plate (14) which is anchored in the concrete and a closed loop member (16) which is force-lockingly connected to said plate and which partially projects from the top (15) of the plate element.

3. Formwork according to claim 2, characterised in that the loop member (16) is of a U-shaped configuration and the internal width between the limb portions of the loop member is at least twice the diameter of a round bar member, or the width of a square or rectangular bar member, said bar member forming the connecting member (11).

4. Formwork according to Claim 1, characterised in that the base portion of the anchor (31) is formed from at least one anchoring loop member (34, 35, 42, 43, 37) which is embedded in the concrete.

5. Formwork according to claim 4, characterised in that the anchoring loop member or members (34, 35, 42, 43, 47) is or are disposed parallel to the plane of the plate.

6. Formwork according to claim 4 or claim 5, characterised in that an anchoring loop member (34, 42, 47) is provided at the underside of the plate element and an anchoring loop member (35, 43) is provided at the top side of the plate element.

7. Formwork according to one of claims 4 to 6, characterised in that the anchoring loop member (42, 43) is in the form of a V-shaped loop member.

8. Formwork according to claim 1, characterised in that the base portion of the anchor comprises at least one sheet metal member (51, 52) which is arranged at the abutting edge of the plate element and which is anchored in the concrete by claws (50).

9. Formwork according to one of claims 1 to 8, characterised in that the head portion has a screw connecting means (39, 40) for fixedly clamping the connecting member.

10. Formwork according to claim 9, characterised in that the head portion comprises a cylindrical portion (36) having an internal screwthread (39).

11. Formwork according to claim 9, characterised in that the head portion comprises a screwthreaded pin (44, 53, 54) with an external screwthread extending from a support surface.

12. A process for the production of a prefabricated plate element for a formwork according to one of claims 1 to 11, wherein, after the reinforcing means has been introduced into and secured in a mould, concrete is introduced into the mould and caused to harden, characterised in that, before the reinforcing means is introduced, at least one anchor having the features of claim 1 is fitted into the formwork in the region of at least one abutting edge, and is fixed with respect to the formwork.

13. An anchor for a formwork according to one of claims 4 to 7, characterised by at least one anchoring loop member (34, 35, 42, 43, 47) to which a screwthreaded pin (44, 59) or a tube member having an internal screwthread is welded, normal to the plane of the loop member, said screwthreaded pin or said screwthreaded tube member having a support surface (37) for a connecting member (38), said support surface extending parallel to the plane of the loop member, at a height which exceeds the thickness of the plate element.

14. An anchor according to claim 13, characterised in that associated with the support surface (37) is a means (40, 45) for clamping a connecting member (38) fixedly on the support surface.

15. An anchor according to claim 13 or claim 14, characterised in that two V-shaped loop members (42 and 43) are welded at a spacing from each other to a screwthreaded pin (44) or a tube member with an internal screwthread.

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