EP2378030B1 - Formwork system - Google Patents

Description

Technical area

The present invention relates to a formwork system for concrete construction.

State of the art

Concrete structures such as floor / ceiling tiles are often concreted in several sections. Reasons for this are, for example, the mixing of new concrete or a break in work between the casting of the individual sections. The shuttering elements used for this purpose are usually made of steel and have larger dimensions, which leads to a high weight and corresponding difficulties in use on the construction site.

From the EP 507 054 A1 a formwork element is known in which the bars of the formwork carrier forming gridwork are arranged on both surfaces of an intermediate metal plate and welded thereto. The formwork element causes an improved anchoring and reinforcement in the concrete and is particularly suitable for Abschalen connection surfaces to which a further concrete section is to be connected later.

In the case of large-volume concrete structures and a correspondingly increased concrete pressure can be on a from the EP 1 132 545 A2 recourse to known formwork material. This formwork material consists of a sheet of expanded metal and transverse or longitudinal stiffening elements on both sides of the panel. The stiffening elements are welded together at the crossing points through the panel. It is also possible that from the EP 507 054 A1 to provide known formwork element with additional stiffening elements.

It goes without saying that the formwork elements described before the concreting must be securely fixed to the reinforcement of the respective concrete structure, since the concreting permanently increasing concrete pressure must not lead to a displacement or even falling over of the formwork element. Usually this fixation happens by a so-called suspension, which consists of welded to reinforcement and formwork element metal rods. Overall, the setting up and fixing of large-sized Abschalelementen is very labor intensive and therefore costly.

One solution to this problem is the DE 20 2008 015 883 U1 which describes a formwork with anchoring device. The rear anchoring device has a tie rod connected to both the shuttering wall and the base. The tension strut is connected to the underlay and / or to the formwork wall via a hook connection containing a flexible loop element. A disadvantage of this system is the complex attachment of the tie rod, in particular at the lower reinforcement layer. The looping of the reinforcing bars with the flexible loop element proves to be quite complex and difficult to carry out in practice.

There is therefore still a need for formwork that can be easily set up and fixed and therefore prove to be relatively inexpensive to use.

Presentation of the invention

This is where the invention starts. The invention, as characterized in the claims, the object of the invention is to provide a shuttering, which can be easily and quickly connected to the reinforcement of the concrete structure and yet securely fixed to the reinforcement.

This object is achieved by the formwork system according to claim 1. Further advantageous details, aspects and embodiments of the present invention will become apparent from the dependent claims, the description, the examples and the drawings.

The formwork system according to the invention for concrete construction comprises a formwork element and at least one suspension. The formwork element comprises a planar formwork part aligned in the installed state substantially perpendicular to a reinforcement layer. The suspension comprises a tension strut, a fastening device for fastening the tension strut to the reinforcement layer and a fastening element for fastening the tension strut to the formwork element. The fastening device has a securing bolt and a loop hook element arranged at the end of the tension strut adjacent the reinforcing layer and having a terminal loop reversal area. The loop-hook element is either hooked around at least one reinforcing bar of the reinforcing layer and the securing bolt is guided between the reinforcing bar and the loop reversing area or the loop-hook element is hooked around the securing bolt and a reinforcing bar of the reinforcing layer is between the securing bolt and the loop reversal area guided.

The loop-hook element according to the invention can be easily obtained by bending a steel bar 30 twice (see FIG Fig. 1A ) such as a black steel bar or a reinforcing steel bar. The steel rod is first bent once such that, for example, the two sections of the rod are substantially parallel to each other and the free ends of the steel rod come to rest flush with each other (see Fig. 1 B) , The ends of the steel rod opposite thereby creates a loop-shaped area, for which a loop reversal area 10 can be defined. This looped, opposite the ends of the steel bar area is then bent a second time, which forms a hook (see Fig. 1C ). The double-curved steel bar represents a loop-hook element 8 according to the invention.

In the region of the two adjacent ends of the steel rod, the loop-hook element can then be attached to the tension strut, in particular welded to the tension strut. In this case, the tie rod made of reinforcing steel, preferably made of a threaded rod. But it can also be a correspondingly long steel rod used to make the loop-hook element, so that the two ends of the loop-hook element forming rod reach up to the formwork element and penetrate it. The fastener in this case has two holes through which the two bar ends of the tension strut are guided. The attachment to the formwork element will be described in more detail below.

The steel rod can also be bent to form the loop-shaped area so that the free ends of the steel rod do not come to lie flush next to each other. The two linear sections of the steel bar with loop have a different length in this case.

By means of the formwork system according to the invention, welding to fix the suspension is completely avoided. The attachment of the fastening device to the reinforcement layer is associated with a much lower labor and time than the welding of the suspension to the reinforcement and the formwork element. In the case of construction sites where any welding is prohibited, the formwork system according to the invention provides a good manageable and cost-effective shuttering available.

When mounting the formwork system according to the invention, first the tension strut is guided obliquely through the planar formwork part at a favorable height. Then, the loop-hook member is hooked to a reinforcing bar of the lower reinforcing layer and the securing bolt is inserted through the clearance formed by the reinforcing bar in which the loop-hook member is hooked and the loop reversing portion. During assembly, the tension strut acts as a support for the formwork element and prevents tipping of the formwork element in the direction of the tension strut. The safety bolt prevents a lateral slipping of the loop-hook element. In addition, it can come in the case of particularly high tensile loads to a bending back of the loop-hook element, which completely loses its grip on the reinforcement layer and thus its function.

It should be mentioned at this point that in the context of the present invention, the term "loop hook element" is also understood to mean an "eye hook element". In such an embodiment, the tension strut is bent at its end facing the reinforcement to a hook and is hooked to a reinforcing bar as already explained. An annular eyelet is attached to the hooked end of the tie rod. The securing bolt is guided through the eyelet and rests on at least one, advantageously three reinforcing bars.

Following the hooking of the loop-hook element in the lower reinforcement and fixing by means of securing bolts, the fastening element for fastening the tension strut to the formwork element is inserted from the rear side of the formwork part onto the tension strut. To secure against falling over the formwork element, it may be advantageous to attach the fastener by means of tie wire to the formwork element. During installation, it turns out to be practicable first to perform all provided for a particular formwork element tension struts through the formwork part to attach to the reinforcement to install all fasteners and only then to lead the individual fasteners to the formwork element and there under train to the tension strut to fix.

Particularly preferably, the securing bolt has a length which exceeds twice the distance between two reinforcing bars of the lower reinforcement layer. In this case, the securing bolt can be inserted so that it is in contact with a total of three reinforcing bars and so distributes the pressure forces transmitted to the securing bolt during a tensile load of the tension strut through the loop reversal area on three reinforcing bars.

In order to facilitate the insertion of the securing bolt into the intermediate space formed by the reinforcing bar into which the loop-hook element is hooked and the loop reversal area, the securing bolt is formed bent in a particularly preferred embodiment.

Preferably, the securing bolt is formed by a reinforcing steel bar.

Preferably, the attachment of the tie rod to the lower reinforcement layer of the concrete structure. However, the present invention also includes embodiments in which the attachment to the upper reinforcement layer takes place. It should also be mentioned that the formwork system according to the invention is described below in connection with the construction of a floor / ceiling panel, but that the formwork system can also be used in the context of wall-floor / ceiling joints and wall-wall joints.

The tension strut is preferably a metal wire or a metal rod. Depending on the nature of the use of the formwork system according to the invention, an optimum thickness of the metal wire or metal rod used as a tension strut can be selected. The higher the expected concrete pressure on the formwork element, the larger the diameter of the metal wire or metal rod must be dimensioned.

According to a preferred embodiment, the planar formwork part has openings. The openings of the sheet-like formwork part are advantageously large enough on the one hand to ensure a durable and stable connection of the concrete of the two contiguous concreting sections, but on the other hand are not so large that the concrete of the first concreting section can flow through the openings.

Particularly preferably, the flat formwork part consists of a metal grid constructed of transverse and longitudinal bars and a panel of expanded metal connected to the bars of the metal grid, the expanded metal bar being arranged between the transverse and longitudinal bars of the metal grid. Preferred are the Cross bars of the metal grid welded to the longitudinal bars of the metal grid at their crossing points. Depending on the nature of the use of the formwork element, an optimization of the thickness of the transverse and longitudinal bars of the metal grid and the distance between the transverse and longitudinal bars can be made to each other. The higher the concrete pressure to be expected on the shuttering element, the thicker the individual bars have to be dimensioned, or the lesser the distance between them, the transverse and longitudinal bars of the metal grid must be used.

The from the EP 507 054 A1 known formwork elements connect in this context, various favorable properties. On the one hand, the expanded metal sheet already has perforations whose size can be adapted to carry out a tension strut in a simple manner by severing individual expanded metal webs. On the other hand, the formwork elements have sufficient intrinsic stability and rigidity to not be deformed by the supporting fasteners.

Preferably, the formwork element comprises at least two transverse bars as additional stiffening elements on the rear side of the flat formwork part. The crossbars increase the stability and rigidity of the formwork element. Particularly preferably, the fastener is supported on the additional transverse rods, which is why in this case the force exerted on the formwork element force can be selected larger.

Alternatively or in addition to the transverse bars, the formwork element preferably comprises a lattice girder attached to the rear side of the flat formwork part as a further stiffening element. By a lattice girder, the stability and rigidity of the formwork element is further enhanced. The fastener is supported in this case either on the lattice girder or on the additional transverse bars.

Such formwork parts and methods for their preparation are known from EP 507 054 A1 known. In the context of the present invention, a very special advantage is associated with the use of this type of formwork parts. The Fastening element for fastening the tension strut to the formwork element engages around the tension strut in the rear region of the formwork part and fixes it firmly to the formwork element. This fixation is done by a tensile load of the tension strut. The fastener is supported on the back of the formwork element.

Preferably, the tension strut is provided with a thread, which is screwed for fastening the tension strut to the formwork part with the fastening element. In this case, the tension strut itself can be provided with a thread or alternatively a threaded rod can be welded to the tension strut. The welding of the threaded rod is already made at the factory, which is why no welding process on the site is required in this embodiment.

The tension strut can be guided through corresponding holes of the fastener, countered by means of a threaded nut and thus firmly connected to the formwork part. Preferably, a nut or clamping sleeve with washer is used as a threaded nut. This type of nut is known as DYWIDAG ^® -nuts, in particular wing nuts on the construction sector.

Likewise, it is possible to provide the fastener with a complementary to the external thread of the tension strut internal thread and screwed in this way tie rod and fastener together. In a further variant, a threaded nut can be welded in alignment with the holes on the fastening element. In this case, the tension strut is passed through the holes of the fastener and bolted to the threaded nut welded to the fastener.

Particularly preferred as a fastener, a conventional formwork lock is used. The formwork lock has a plate which is supported on the formwork element and which has a certain mobility and can easily be tilted. The plate is therefore oriented substantially parallel to the formwork part, although the tension strut is guided obliquely through the plate.

Particularly preferably, the formwork system comprises several suspensions. Depending on the dimension of the concrete structure to be built and the expected concrete pressure, it may be necessary to provide several suspensions to ensure a secure fixation of the formwork element. Several suspensions may be required both in the direction of the vertical extent of the formwork element as well as in the direction of the horizontal extent of the formwork element.

A first tension strut preferably meets the shuttering element at a height of about 20 cm. Particularly preferred in addition per 80 cm vertical extension of the sheet-like formwork part a further suspension is provided. In a fitting dimension of the formwork element of about 2 m so three suspensions are required for secure fixation of the formwork element. The installation dimension of the formwork element corresponds to the distance between the lower and upper reinforcement. The anchoring elements penetrate the formwork part at heights of around 20 cm, around 1 m and around 1.80 m.

However, such an arrangement of a plurality of tensile struts which are tensioned one above the other can also be required to be arranged several times next to one another, depending on the horizontal extent of the concrete structure. In this context, it is preferable to provide a further suspension per 80 cm horizontal extent of the flat formwork part. If, for example, the 2 m thick concrete pavement given as an example above has, for example, a horizontal extension of 10 m, the group of three vertically superimposed suspensions is placed approximately 13 times next to one another.

Brief description of the drawings

Fig. 1A

einen Baustahlstab;

Fig. 1B

den zur Bildung einer Schlaufe einmal gebogenen Baustahlstab der Figur 1A;

Fig. 1C

den zur Bildung eines Schlaufen-Haken-Elements zweimal gebogenen Baustahlstab der Figur 1A;

Fig. 2

einen vertikalen Schnitt durch eine Bodenplatte mit dem erfindungsgemäßen Schalungssystem;

Fig. 3

eine vergrößerte Darstellung des Bereichs der Befestigung des Schlaufen-Haken-Elements der Zugstrebe an der Bewehrung;

Fig. 4

für eine weitere Ausführungsform eine vergrößerte Darstellung des Bereichs der Befestigung des Schlaufen-Haken-Elements der Zugstrebe an der Bewehrung;

Fig. 5

für eine weitere Ausführungsform eine vergrößerte Darstellung des Bereichs der Befestigung des Schlaufen-Haken-Elements der Zugstrebe an der Bewehrung;

Fig. 6

eine vergrößerte Darstellung des Bereichs der Befestigung der Zugstrebe an dem Schalungselement.

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. It is explicitly stated that the invention should not be limited to the examples given. Show it

Fig. 1A

a structural steel rod;

Fig. 1B

the once bent to form a loop wire rod of the Figure 1A ;

Fig. 1C

the twice bent to form a loop-hook element Baustahlstab the Figure 1A ;

Fig. 2

a vertical section through a bottom plate with the formwork system according to the invention;

Fig. 3

an enlarged view of the region of attachment of the loop-hook element of the tension rod to the reinforcement;

Fig. 4

for a further embodiment of an enlarged view of the region of attachment of the loop-hook element of the tension rod to the reinforcement;

Fig. 5

for a further embodiment of an enlarged view of the region of attachment of the loop-hook element of the tension rod to the reinforcement;

Fig. 6

an enlarged view of the region of attachment of the tie rod to the formwork element.

Ways to carry out the invention

The Figures 1A, 1B and 1C illustrate the production of the loop-hook element according to the invention by double bending a structural steel rod 30th (please refer Fig. 1 A) , The steel rod is first bent once so that the two sections of the rod are substantially parallel to each other and the free ends of the steel rod come to lie flush next to each other (see Fig. 1 B) , The ends of the steel rod opposite thereby creates a loop-shaped area, for which a loop reversal area 10 can be defined. This looped, opposite the ends of the steel bar area is then bent a second time, which forms a hook (see Fig. 1C ). The double-curved steel bar represents a loop-hook element 8 according to the invention.

The FIG. 2 shows a vertical section through a bottom plate. Shown are the lower reinforcement 6, the upper reinforcement 16, a formwork element 1 and two suspensions 2. The formwork element 1 comprises a planar formwork part 3 with a front facing the first concreting BA1 and a second concreting BA2 facing back. The sheet-like formwork part 3 consists of a cross-14 and longitudinal bars 15 constructed metal grid (see FIG. 6 ) and an expanded metal sheet 17 connected to the bars of the metal grid. As transverse and longitudinal bars, for example, bars made of structural steel can be used, as they are also used for reinforcing mats or the like. The sheet 17 of expanded metal is disposed between the transverse 14 and the longitudinal bars 15 of the metal grid. At the back of the sheet-like formwork part 3, a lattice girder 19 is attached as an additional stiffening element.

The two suspensions 2 are identical with the exception of the length of the respective tie rods 4. To fasten a tension strut 4 to the lower reinforcement 6, a loop-hook element 8 and a securing bolt 5 is used to fasten the tension strut 4 to the formwork element 1, a shuttering lock 7 is used.

In a fitting dimension of the formwork element 1 of about 1.20 m two suspensions 2 are required for secure fixation of the formwork element. The installation dimension of the formwork element 1 corresponds to the distance between the lower and upper reinforcement. A first suspension hits about 20 cm above the bottom Reinforcement on the flat formwork part 3. The second suspension is attached about 80 cm above the first suspension to the formwork element 1. Both tie rods 4 meet at an angle of about 45 ° on the sheet-like formwork part 3, penetrate the formwork part 3 and occur in the same direction at the back of the formwork part 3 from this.

The FIG. 3 shows enlarged the range of attachment of the loop-hook element 8 of the tie rod to the lower reinforcement. The lower reinforcement is shown in the form of two layers of reinforcing bars, the lower layer of reinforcing bars consisting of reinforcing bars 22 extending substantially parallel to each other and the upper layer of reinforcing bars being constructed of reinforcing bars 24a, 24b, 24c arranged substantially parallel to each other. The reinforcing bars 22 of the lower layer of reinforcing bars are oriented substantially perpendicular to the reinforcing bars 24a, 24b, 24c of the upper layer of reinforcing bars. The entire reinforcement layer can be constructed in the usual way of reinforcing mats.

In the illustrated embodiment, the loop-hook element 8 is hooked around a reinforcing bar 24b of the upper layer of reinforcing bars. The securing bolt 5 is guided between the reinforcing bar 24 b and the loop reversing area 10 of the loop-hook element 8. The securing bolt 5 also rests on the reinforcing bars 24a and 24c. If there is a tensile load of the tension strut and thus of the loop hook element 8 in the direction of the formwork element, the loop reversal area 10 exerts a compressive force on the safety bolt 5. This pressure force is transmitted from the securing bolt 5 to the three reinforcing bars 24a, 24b and 24c and thus distributed in the reinforcement layer.

The FIG. 4 shows for a further embodiment increases the range of attachment of the loop-hook element 8 of the tension strut to the lower reinforcement. The lower reinforcement is shown in the form of two layers of reinforcing bars, the lower layer of reinforcing bars consisting of substantially mutually parallel reinforcing bars 22a, 22b, 22c and the upper tier of reinforcing bars being substantially parallel Reinforcing bars 24 arranged to each other is constructed. The reinforcing bars 22a, 22b, 22c of the lower layer of reinforcing bars are oriented substantially perpendicular to the reinforcing bars 24 of the upper layer of reinforcing bars. The entire reinforcement layer can be constructed in the usual way of reinforcing mats.

In the illustrated embodiment, the loop-hook element 8 is hooked around a reinforcing bar 22b of the lower layer of reinforcing bars. The securing bolt 5 is guided between the reinforcing bar 22 b and the loop reversing area 10 of the loop-hook element 8. The securing bolt 5 also rests on the reinforcing bars 22a and 22c. If there is a tensile load of the tension strut and thus of the loop hook element 8 in the direction of the formwork element, the loop reversal area 10 exerts a compressive force on the safety bolt 5. This pressure force is transmitted from the securing bolt 5 to the three reinforcing bars 22a, 22b and 22c and thus distributed in the reinforcement layer.

The FIG. 5 shows for a further embodiment increases the range of attachment of the loop-hook member 8 of the tie rod 4 to the lower reinforcement. The lower reinforcement is shown in the form of two layers of reinforcing bars, the lower layer of reinforcing bars consisting of reinforcing bars 22a, 22b, 22c, 22d extending substantially parallel to each other and the upper layer of reinforcing bars being constructed of reinforcing bars 24 arranged substantially parallel to each other , The reinforcing bars 22a, 22b, 22c, 22d of the lower layer of reinforcing bars are oriented substantially perpendicular to the reinforcing bars 24 of the upper layer of reinforcing bars. The entire reinforcement layer can be constructed in the usual way of reinforcing mats.

In the illustrated embodiment, the loop-hook element is hooked around the securing bolt 5. The reinforcing bar 22b is guided between the securing bolt 5 and the loop reversing portion 10 of the loop-hook member. The securing bolt 5 rests on the reinforcing bars 22a and 22c. If there is a tensile load of the tension strut 4 and thus the Loop hook element in the direction of the formwork element so the loop reversal area 10 exerts a compressive force on the reinforcing bar 22b. The reinforcing bar 22b is fixedly connected to the reinforcing bars 24, whereby the compressive force is transmitted in the form of a tensile force on the reinforcing bars 24 and distributed in the reinforcement layer. Smaller portions of the compressive force exerted by the loop reversal portion 10 are transferred from the reinforcing bar 22b to the securing bolt 5 and thus to the reinforcing bars 22a and 22c.

In the FIG. 6 is shown enlarged the range of attachment of the tie rod 4 to the formwork element. The tension strut 4 penetrates the planar formwork part 3 and exits from the rear side of the formwork part 3 from this. The formwork lock used as a fastening element engages around the tension strut 4. In the illustrated embodiment, the tension strut 4 penetrates the formwork lock linearly. Of course, the tension strut 4 may be bent in the region of the formwork lock and, for example, at an angle of about 90 ° relative to the plane of the formwork part 3 escape from this.

The formwork lock is a formwork fastening element which comprises a plate 20 and a wing nut 21. At the back of the sheet-like formwork part 3, two additional transverse bars 18 are mounted for further stiffening of the formwork element. The plate 20 is supported on the back of the formwork part 3 at the additional transverse bars 18. By tightening the wing nut 21, the tension strut 4 is firmly fixed to the formwork part 3.

LIST OF REFERENCE NUMBERS

BA 1

first concreting section

BA 2

second concreting section

1

An element

2

suspension

3

form member

4

tension strut

5

safety bolt

6

lower reinforcement

7

fastener

8th

Loops Hook element

10

Loop reversal region

14

cross bar

15

longitudinal bar

16

upper reinforcement

17

Expanded metal panel

18

additional crossbar

19

girder

20

Plate

21

butterfly nut

22

rebars

22a, 22b

rebars

22c, 22d

rebars

24

rebars

24a, 24b

rebars

24c

rebar

30

structural steel rod

Claims (11)

1. A formwork system for concrete construction, comprising a formwork element (1) and at least one suspension (2), wherein the formwork element (1) comprises a flat formwork part (3) aligned essentially perpendicularly to a reinforcing layer (6) in the installed state, wherein the suspension (2) comprises a tie rod (4), a fastening device for fastening the tie rod (4) on the reinforcing layer (6) and a fastening element (7) for fastening the tie rod (4) on the formwork element (1), characterised in that the fastening device for fastening the tie rod (4) on the reinforcing layer (6) comprises a securing bolt (5) and a loop-hook element (8) arranged at the end of the tie rod (4) adjacent to the reinforcing layer (6), with a terminal loop reversal region (10), wherein the loop-hook element (8) is hooked around at least one reinforcing rod (22b, 24b) of the reinforcing layer (6) and the securing bolt (5) is guided between the reinforcing rod (22b, 24b) and the loop reversal region (10) or the loop-hook element (8) is hooked around the securing bolt (5) and a reinforcing rod (22b) of the reinforcing layer (6) is guided between the securing bolt (5) and the loop reversal region (10).
2. The formwork system according to claim 1, characterised in that the tie rod (4) consists of a metal wire or a metal rod.
3. The formwork system according to one of the preceding claims, characterised in that the flat formwork part (3) has through holes.
4. The formwork system according to one of the preceding claims, characterised in that the flat formwork part (3) consists of a metal lattice constructed from transverse (14) and longitudinal rods (15) and a panel (17) made from expanded metal, which is connected to the rods of the metal lattice, wherein the panel (17) made up of expanded metal is arranged between the transverse (14) and longitudinal rods (15) of the metal lattice.
5. The formwork system according to one of the preceding claims, characterised in that the formwork element (1) has transverse rods (18) fastened on the rear side of the flat formwork part (3) as additional reinforcing element.
6. The formwork system according to one of the preceding claims, characterised in that the formwork element (1) has a lattice girder (8) fastened on the rear side of the flat formwork part (3) as additional reinforcing element.
7. The formwork system according to one of the preceding claims, characterised in that the tie rod (4) penetrates the flat formwork part (3) and the fastening element (7), for fastening the tie rod (4) on the formwork element (1), encompasses the tie rod (4) in the rear region of the formwork part (3) and fixes the same on the formwork element (1).
8. The formwork system according to one of the preceding claims, characterised in that a formwork lock is used as fastening element (7) for fastening the tie rod (4) on the formwork element (1).
9. The formwork system according to one of the preceding claims, characterised in that a plurality of suspensions (2) are provided.
10. The formwork system according to claim 9, characterised in that one suspension (2) is provided per approximately 80 cm vertical expansion of the flat formwork part (3).
11. The formwork system according to one of claims 9 and 10, characterised in that one suspension (2) is provided per approximately 80 cm horizontal expansion of the flat formwork part (3).

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