AT519067B1 - DEHNFUGENSCHALUNG - Google Patents

Abstract

The invention relates to a formwork for expansion joints in concrete construction, in which a back anchoring of a formwork element has a flexible, the shuttering wall passing through tension element which is coupled to the second concrete section BA2 side facing the formwork element with this.

Description

description

DEHNFUGENSCHALUNG

The invention relates to a formwork for producing an expansion joint according to the preamble of patent claim 1.

Concrete structures are usually created in sections, forming joints between the temporally successively generated concreting sections. These are either construction joints, if the concreting immediately, at best, with the interposition of a lost formwork, abut, or expansion joints, if between adjacent concreting sections a gap remains, which is filled by a deformable parting line insert. Expansion joints are provided so that the hardened concreting sections can expand under the influence of heat or can move relative to one another when forces are applied to the structure without damaging the concrete.

At the boundary of a concreting a formwork with a formwork panel is arranged, which prevents a frontal outflow of the concrete from the concreting section. The still flowable concrete exerts a significant hydrostatic pressure on the formwork panel. In order to prevent the formwork panel from being forced away during the casting of the concreting section to be produced first, it is known to provide a re-anchoring device. This has at least one tension member, which is connected at one end to the formwork wall and the other end on the Erstbetonierabschnitt facing side of the formwork wall with the static reinforcement or a ground anchor. This creates a bracing of the formwork panel against the concrete pressure.

For lost formwork for construction joints, it is known for example from EP 2,157,260 A1 or EP 2 192 237 A2 to use as a tie-back tension member a rod-shaped tension strut, which passes through the formwork panel at one end and there with a Screw is secured while it is connected at its other end directly or via a hanger or a Einhängeschlaufe with the static reinforcement. Such Rückverankerungseinrichtungen are very well for lost Stirnabschalungen of construction joints. However, they are not suitable for the construction of expansion joints, because an expansion joint must not be crossed by a rigid component in order not to hinder the mobility of the concrete sections in the joint.

In formwork for expansion joints has therefore waived either to a back anchoring, or attached to the rear anchoring tension member on the first concreting facing side of the formwork panel. The tensile forces that occur due to the concrete pressure between the formwork wall and the tension member lead to undesirable deformations in the formwork panel or the other structural parts of the formwork element. This can be prevented only by an elaborate, usually made of lattice girders stiffening construction on the first concreting facing side of the formwork element. Such additional measures are time-consuming and costly.

Finally, for example from DE 101 02 660 A1 and DE 195 33 421 C1, already known back anchoring devices consisting of ropes, wires or bands attached to the first to be concreted section facing side of the formwork panel and on be hung in the reinforcement or an anchor at the other end. Also in this case, tensile forces on the formwork panel or the formwork element arise from the side of the first section to be concreted ago, which are difficult to record and deform the formwork.

The invention is therefore an object of the invention to provide a specially suitable for generating an expansion joint formwork according to the preamble of claim 1, wherein the concrete pressure resisting Rückverankerungskräfte initiated favorably in the formwork element and relative movements of adjacent in the expansion joint concrete components not hindered.

This object is achieved according to the invention in a generic formwork by the characterizing features of claim 1.

In the formwork according to the invention, the tensile forces occurring in the return anchorage for receiving the concreting pressure are passed through a flexible tension member through the formwork panel and are introduced via stable parts of the support structure as compressive forces from the side of the secondary concrete section forth in the formwork panel. As a result, unfavorable loads on the parts of the formwork panel and the joints of these parts are avoided with the support structure, since only pressure forces occur in the critical areas. A flexible tension element in the sense of the invention is to be understood as meaning that, although the tensile forces occurring during the return anchoring can be transmitted reliably, they deform under pressure or under lateral load but without much resistance. If the faces of the expansion joint adjacent concrete parts expand under heat influence and approach each other in the joint area, the tension element is merely compressed, hinders the thermal movement of the concrete parts, however, as little as the Dehnfugenfüllmasse compressing in this process. Shifts the faces of the concrete parts parallel to each other, so occur in the region of the tension element shear forces, which gives the tension element without much resistance, so that it does not hinder the free mobility of the concrete parts in this respect. In extreme cases, the flexible tension member is sheared in shear movements of the concrete parts and acts in such a case as a kind of predetermined breaking element.

As a tension element is particularly suitable according to claim 2 a rope. Such is known to be composed of a plurality of twisted strands and is therefore able to transmit high tensile forces, while it compresses easily by compressive forces and can be turned sideways without much resistance.

Instead of a rope can be used according to claim 3, a simpler and cheaper wire, if the expected loads are not too high.

According to claim 4 is suitable as a material for the tension element metal, preferably steel.

Since recently corroding components are undesirable in joints of concrete structures, formwork panels are used, the cover plates are made of stainless steel. In such a case, advantageously, the tension element made of stainless steel, so that this also does not introduce corrosive materials in the expansion joint.

If the forces to be transmitted are not too large, the tension element can also consist of natural fibers, especially hemp, or plastic or a mixture of these materials according to claim 6. This can save costs and solve the problem of corrosion in a cheap way.

The existing of a rope or wire tension element advantageously has a diameter which is between about 3 and about 8 mm. For smaller diameters, the risk of tearing during re-anchoring is too great and for larger diameters the flexibility of the tension element suffers.

As optimal diameter dimensions between about 4 and about 5 mm have been found in existing steel tensile elements.

Thus, the tension member can move during the back anchorage in the longitudinal direction relative to the shuttering panel is provided according to claim 9 advantageously that the tension element passes through the formwork panel in an opening with a diameter which is slightly larger than the diameter of the tension element. The size difference should be chosen so that the tension element can move when applying tensile forces relative to the form panel without much resistance and without damaging the formwork panel; However, the difference in diameter must be so small that between the tension element and the edge of the opening no or only slightly penetrate concrete.

Advantageously, the tension member has the features of claim 10. A tension member in the form of a closed loop can be anchored on both sides of the formwork panel in a simple manner by the loop wrapped around suitable rigid parts of the formwork element and either by itself or by the intermediary of a tie rod on the Reinforcement or a ground anchor is attached.

Further features and advantages of the invention will become apparent from the following description of an embodiment in conjunction with the drawings. 1 shows a vertical section through a formwork element for an expansion joint with a part of a back anchoring tension member according to the invention, inserted into the static reinforcement of a sole plate to be concreted; FIG. 2 shows the formwork element according to FIG. 1 with rear anchoring tension members, FIG. 3 a detail view, and

The embodiment of the invention shown in Fig. 1 and 2 has a two-part formwork element 1, which serves for Abschalen a bottom plate on a cleanliness layer 2. The bottom plate is concreted in temporal succession of a construction section BA1 and a construction section BA2. Between the construction sections an expansion joint should be created.

The formwork element 1 has an upper part 1a and a lower part 1b. The formwork element 1 includes a two-part formwork wall 3, the upper part of which are designated 3a and the lower part of 3b. The two parts of the formwork wall 3 are composed of a central parting line insert 4, for example, a 20 mm thick mineral fiber board, and from the joint insert on both sides covering cover plates 5 constructed. The cover plates 5 and the parting line insert 4 are firmly connected by means of screws 6, can in other material of the joint insert, z. B. Styrodur, but also glued together. At its upper edge in the installed state, the shuttering wall 3 is enclosed by a joint finishing strip 7.

The cover plates 5 are composed of individual metal sheets. Each metal sheet is in the manner shown in the drawing on a horizontally extending in the installed state edge or on both horizontal edges so folded that arise from the formwork wall 3 transversely projecting Abhang leg. The cover plates are arranged in the manner shown in FIG. 1 in the assembled state so that their Abkantschenkel lie flat against each other. The Abkantschenkel are, for example, by spot welding, screws or rivets, firmly connected together in abutting state, so that double-walled spacers 8 arise, whose function will be explained below.

The two parts of the formwork element 1 each have on both sides of the formwork wall 3 for transporting and handling of the formwork element serving support structure 15 with a bracket assembly 9. Each bracket assembly consists of multiple bent metal bars, each having a plane parallel to the shuttering wall 3 and in the installed state extending portion 9a. For further details of the bracket arrangements 9 reference is made to DE 20 2014 004 206 U1, the disclosure content of which is hereby incorporated into the content of the present disclosure.

The bracket assemblies 9 form in the assembled state shown in FIG. 1, a joint tape cage 10 which receives a conventional elastic joint tape 11. The joint tape 11 is received and clamped with its central, thickened part in a known manner in a slot 12 which forms between the mutually facing edges of the formwork wall parts 3a, 3b in that they are positioned at a certain distance from each other. Each bracket assembly 9 is fixedly connected to the associated shuttering wall portion 3a, 3b via the above-mentioned spacers 8, by the exposed edges of the spacers 8, which are transverse to the U-bar sections 9a extending with these, welded. The cross-sectionally L- or U-shaped folds stiffen the cover plates 5 and thus the formwork wall 3 against bending under the concrete pressure. The stiffening effect is therefore particularly pronounced because the spacers 8, which are made up of abutting limbs, are double-layered. At the same time, the spacers 8 form the connection between the parts 3a, 3b of the form panel 3 and the associated bow assemblies 9 in such a way that the bow assemblies with their parallel to the formwork wall 3 bar sections 9a sufficient for effective concrete coverage of the formwork panel distance of usually 30th mm in building construction and 60 mm in civil engineering.

The Abkantschenkel are slightly inclined in the recognizable manner from the drawing relative to the plane of the shuttering wall 3 and in the installed state of the shuttering element upwards to facilitate the inflow of the concrete. The inclination of the Abkantschenkel relative to the plane of the cover plates is about 15 ° relative to the vertical to the sheet plane.

The formwork element 1 is placed and adjusted on the cleanliness layer 2 by means of support screws 13.

In order to avoid the occurrence of corrosion in the expansion joint, a stainless steel is used as a material for the cover plates and expediently also for the screws 6. For example, grade 4.1016 steel is suitable. Since the distance between the surfaces of the formwork wall 3 and the sections 9a of the bracket assemblies 9 is at least 30-60 mm, thereby found within the concrete cover of the expansion joint no corrosion-prone material, which improves the quality and in particular life of the joint. For the cover plates, due to the stiffening by the folds, a material thickness of 0.5-1.0 mm is sufficient, whereby an economical use of expensive stainless steel material is ensured.

As is apparent from Fig. 1 and 2, the formwork element 1 is inserted into the static reinforcement 14 of the sole plate. In order to be able to absorb the force emanating from the concrete pressure on the formwork element 1 without undue displacement thereof, a back anchoring is provided whose embodiment according to the invention is described below: FIG. 1 shows that the formwork wall 3 bores in the upper and in the lower part 16, whose diameter is to be in the range between 6 and 20 mm and is preferably 8 mm. Through the holes 16, a flexible tension element 17 is ever plugged, which is formed in the illustrated embodiment as a closed loop, which consists in the case shown of a wire of stainless steel. The loop-shaped tension element 17 generally has the property of being able to transmit essentially only tensile forces and no compressive forces, as is the case, for example, with a cable which can be subjected to tension, but which is merely pushed open when pressure forces occur.

The tension member 17 is mounted on the side of the temporally after the first section BA1 to be concreted second section BA2 at the local support structure 15. For this purpose, in the illustrated embodiment, an existing reinforcing steel suspension rod 18 is provided, which is welded in each case between adjacent and spaced apart brackets 9 at the free edges of the spacers 8 and the folds of the cover plates.

The details of the construction described above are shown in Fig. 3 schematically on an enlarged scale. There is also a clasp 19 can be seen, with the ends of the cable loop 17 are connected together.

In addition, an alternative construction is shown in Fig. 3 on the left, in which between the shuttering wall 3 and the bracket assembly 9 and the suspension rods 18 spacers 19 a are arranged in the form of spatial lattice girders. In this case, then the folded spacer 8 can be omitted. The latter construction is particularly suitable if no stainless steel is used for the formwork element.

Fig. 2 shows the formwork element 1 with full back anchoring. Since the parts of the formwork element 1 in FIG. 2 are the same as in FIG. 1, no reference numerals denoting these parts are entered in FIG.

From Fig. 2 are re-anchoring tension members 20 can be seen, consisting of the previously described loop-shaped, flexible tension elements 17 and in this on the side of the first to be concreted section BA1 hook-shaped ends 21 hinged tension rods 22. These tension rods 22 are suspended at their ends 23 remote from the hook-shaped ends 21 (only visible at the lower of the two supports 22) in the static reinforcement 14 there.

In the embodiment shown for hooking a multiple in itself angled bracket 25 is provided, as shown in detail in Fig. 7-10 of EP 2,157,260 A1 and described in connection with these figures. The content of EP 2 157 260 A1 is made the subject of the present disclosure. This also applies to further ironing training, as can be found in the cited publication.

The end 23 of the tension rod 22 is formed as a corrugated reinforcing steel bar on which a nut 26 is screwed. Between the nut 26 and the bracket 25, a perforated flat bar 27 is inserted, via which the nut 26 is supported on the bracket 25. With this screwing the pull rod 22 can be moved in Fig. 2 to the left, so that the bores 16 longitudinally movable passing through loop-shaped tension members 17 stretched and the formwork element in Fig. 2 to the left against the static reinforcement 14 is pulled.

When concreting the first section BA1 then the concrete pressure is transmitted from the shuttering board 3 via the rear anchoring tension members 20 on the static reinforcement 14 and the formwork element 1 anchored back in this way.

It is essential that in the back-anchoring according to the invention serving to form a joint expansion panel 3 is not penetrated by rigid components, but only by the flexible tension elements 17, which does not hinder the approximation of hardened concreting BA1 and BA2 under heat influence in the concrete structure and also allow a parallel displacement of the end walls of the adjacent concreting sections relative to the expansion joint, if necessary by shearing the tension members. It is also important that the re-anchoring forces do not act as tensile forces on the parts of the formwork element 1, but are initiated by the Zweitbetonierabschnitt BA2 as compressive forces in the formwork element. Compressive forces can be structurally better supported there. This applies both when the pressure forces are introduced from the suspension rod 18 via the spacers 8 and the Blechabkantungen in the shuttering wall 3, and in particular when a support element 19a (Fig. 3 left) between the suspension rod 18 and the formwork panel. 3 is inserted.

As already mentioned, in the embodiment shown, the tension member 17 consists of a rope, which is preferably twisted from strands of stainless material. Optionally, but also a wire for the tension element can be used for cost reasons. Both the rope and the wire are preferably made of metal, especially steel, and the diameter should be between about 3 and about 8 mm and preferably about 4 to about 5 mm.

As shown in Fig. 3, the strands of the loop-shaped tension member 17 can also be guided separately through holes 17 in the shuttering wall 3. The bores 16 can, instead of being oriented perpendicular to the plane of the formwork wall, also obliquely through this plane, in the direction of the tensile forces occurring, as shown in FIG.

Instead of a metal cord, a rope or wire made of natural fibers, especially hemp, or made of plastic or a mixture of these materials can be used in less stressed formwork.

It is also conceivable, instead of hanging on a separate suspension rod 18, the tension member 17 to a portion of the bracket assembly 9, in particular to one of the straight bracket sections 9 a, to loop. In this case, an additional component is saved.

Instead of a loop-shaped tension element can also be used from a simple strand, which has at both ends Einhängemittel, such as hooks or eyes, with which it can be attached to the support structure or a pull rod.

Instead of hooking the rear anchoring tension member to the static reinforcement, it can also be hung in a ground anchor.

In the embodiment of Fig. 4, the formwork element 1 is constructed the same as in Figs. 1 and 2 and will therefore not be described again.

Modified with respect to the embodiment of FIGS. 1 and 2 is in Fig. 4, the Rückver-anchoring tension member 20 '. It has an enlarged, loop-shaped tension element 17 ', which is attached at one end to the BA2 side of the formwork element 1 at this and the other end is suspended in a tension rod device 30. This has a tie rod 31 made of corrugated reinforcing steel, which has a hook 32 for attaching the loop-shaped tension element 17 'at its end facing the shuttering element 1. At the other end of the tie rod 31 a hook portion 33 is slidably slid onto this with a pierced foot 33 a, which is adjustable with a clamping nut 34 along the tie rod 31, so as to tension the rear anchor tension member 30. The hook part 33 is hooked with a hook end 33b in a cable loop 35, which in turn is anchored in the static reinforcement 14. The details of the latter construction can be found in EP 2 192 237 A2 in FIG. 5 and the associated description. The disclosure of EP 2 192 237 A2 is made the subject of the present disclosure for this purpose.

Of course, the cable loop 35 can be mounted in other ways in the reinforcement 14 or a ground anchor, for example, be wrapped only around a transverse bar of the reinforcement.

It is essential that also in the embodiment of FIG. 4, the anchoring forces on the side of the second concrete BE2 be introduced as compressive forces in the formwork element 1.

Instead of the loop-shaped elements 17 ', 35 and single-stranded tension elements can be used with hooks or eyes or other coupling parts at the ends, as long as it is ensured that they are able to transmit only tensile forces substantially, as is the case with ropes or wires is.

Claims (10)

claims 1. Formwork for producing an expansion joint between a first section to be concreted first time (BA1) and a second section (BA2) to be concreted in concrete construction, with a permanent formwork element (1) having a deformable parting line insert (4) between cover plates on both sides (5 ) and one with the shuttering wall (3) fixedly connected, on both sides of the formwork wall (3) arranged supporting structure (15), and with a rear anchoring tension member (17, 22), the formwork element (1) back-anchored against the concrete pressure in the first section (BA1) on the first section on the static reinforcement (14) or on the ground (2), characterized in that the rear anchoring tension member (17, 22) has a flexible tension element (17), the tensile forces, but in the Substantially no compressive forces to transfer, and that the formwork wall (3) longitudinally passing through enforcing the second section side on the local support structure (15) is over. 2. Formwork according to claim 1, characterized in that the tension element (17) is a rope. 3. Formwork according to claim 1, characterized in that the tension element (17) is a wire. 4. Formwork according to one of claims 2 or 3, characterized in that the rope or the wire made of metal, preferably steel. 5. Formwork according to claim 4, characterized in that the rope or the wire is made of stainless steel. 6. Formwork according to claim 2 or 3, characterized in that the rope or the wire made of natural fibers, especially hemp, or of plastic or of a mixture of these materials. 7. Formwork according to one of claims 2 to 6, characterized in that the cable or the wire has a diameter of about 3 mm to about 8 mm. 8. Formwork according to claim 7, characterized in that the cable or the wire has a diameter of about 4 mm to 5 mm. 9. Formwork according to one of claims 1 to 8, characterized in that the tension element (17) passes through the formwork panel (3) in at least one opening (16) whose diameter is slightly larger than the diameter of the tension element. 10. Formwork according to one of claims 1 to 9, characterized in that the tension element (17) forms a closed loop, which passes through the formwork wall (3) in one or two openings (16) and the second section side to a suspension rod (18) or Bracket (9) of the support structure (15) looped and the first section on one end (21) of a rod-shaped tie rod (22) is mounted, the other end (23) directly or through the intermediary of a Einhängebügels (25) or a Einhängeschlaufe on the static reinforcement ( 14) or attached to a ground anchor.