EP3029220B1 - Transport anchor for prefabricated reinforced concrete double walls - Google Patents

Description

TECHNICAL AREA

The invention relates to a prefabricated reinforced concrete double wall with at least one transport anchor comprising a steel bracket with a curved central section for hanging the slinging means and on both sides adjoining this, in sections parallel to each other, and a bracket legs arranged between the bracket legs, with these under the loads to be absorbed its longitudinal direction not rigidly connected, with its ends embedded in the shells pressure element.

STATE OF THE ART

A transport anchor for reinforced concrete double walls with two shells is made of, for example DE 10 2005 009 708 B4 known. The pressure element is formed there from a flexible material such as wood, plastic or textile fiber concrete. The bracket legs are each inserted into end-side, channel-shaped recesses of the pressure element. The bracket legs are held together in their parallel alignment by a bracket in the end area of the bracket legs, which overlaps them in a U-shape. At the same time, the pressure element is thereby clamped between them.

With such transport anchors provided with wooden pressure elements, sufficiently high load-bearing capacities can be achieved in practice. These are significantly higher than those with anchor types, for example according to DE 297 06 644 U1 or DE 100 38 249 A1 achievable load capacities, with which steel pressure elements are welded onto the bracket legs. With these types of anchors, concrete spalling occurs under load. With the transport anchor according to DE 297 06 644 U1 the bracket legs are bent at their free ends out of the plane of the steel bracket in a semicircle.

the WO2003104577 A relates to a building element made of masonry blocks, wherein means are provided for lifting the element which comprise rods which extend vertically through the masonry blocks and are arranged in channels which run in superimposed masonry blocks. The bars are attached to the masonry block by means of a casting compound.

the DE19853712 A discloses a transport and laying anchor for hollow and filigree walls, with longitudinal anchoring legs running next to one another, which are connected with their first ends to form a closed transport loop and on which at least one crosspiece is fixed. The transverse web extends transversely or obliquely to the longitudinal direction of the transport and laying anchor or the longitudinal anchoring legs. The transverse web is brought into engagement with the respective longitudinal anchoring leg via a snap-in, latch-in or plug connection. The transverse web and the longitudinal anchoring legs are connected in a form-fitting and / or force-fitting manner.

the DE102011055 A2 relates to a double wall with a first shell, a second shell, in particular parallel to the first shell, and at least one transport anchor, the transport anchor having a bracket with two legs between which a pressure rod, in particular a steel pressure rod, is arranged. One leg is arranged in the first shell and the other of the legs is arranged in the second shell. The double wall is characterized in that the first shell and / or the second shell 10) and / or at least one of the legs are arranged to be movable in at least one direction relative to the pressure rod. Alternatively or additionally it can be provided that at least a first end of the pressure rod is provided with a transmission element, in particular an elastic element and / or a cap, which has a contact surface which - preferably over the entire surface - is in contact with the first shell and that the area of application of force of the forces exerted by the pressure rod on the first shell is increased.

DISCLOSURE OF THE INVENTION

The object of the invention is to further improve reinforced concrete double walls of the type mentioned at the beginning with regard to the transport anchor. This object is achieved by the measures specified in claim 1.

The invention thus provides, inter alia, for the pressure element to be made of steel. The invention is based on the fact that the problems that occurred with pressure elements made of steel in the known anchor types were less the material of the pressure element than the rigid connection of the pressure element with the bracket legs by welding. By dispensing with such a rigid connection, the invention can use steel again as the material for the pressure bolt. This results in the following advantages, among others:
A pressure bolt made of steel does not form a moisture bridge between the two shells of the double wall, as can be the case with the water-absorbing and forwarding pressure bolts made of wood. When the shells are poured, the poured concrete does not bond absolutely tightly to the shells, so that water can penetrate between the shells and the poured concrete. One speaks of backwardness here. The wooden pressure elements allow the water to cross the layer of the poured concrete, so that additional sealing measures may be required.

Problems with the wooden pressure elements also arise in the manufacture of the double walls. First, one of the two shells is poured into a formwork designed with the usual lattice girders for reinforcing this shell and provided with the required number of transport anchors. The second shell is created accordingly and, after it has hardened, the first shell is placed on top of it and pressed into the fresh concrete. When concreting the first shell, the reinforcement parts protruding from the concrete of this shell, including the transport anchor (s), are covered with a porous concrete layer, which is unfavorable for their embedding in the concrete of the second shell and in the concrete later poured between the shells. This concrete layer is then usually at least partially removed by plastering. However, since it adheres more strongly to wood than to steel, its removal from the wood printing elements is often insufficient. In the finished wall, the porous concrete layer forms, in addition to the wood material, a layer that is permeable to water.

A higher buckling stability can be achieved with pressure bolts made of steel. At least steel pressure bolts can be made slimmer than those made of wood with comparable buckling stability.

The bracket legs or the steel bracket as a whole can also be made slimmer when using a steel pressure bolt. A slimmer design of the steel bracket, possibly using a higher quality steel, reduces the weight of the transport anchor. In the case of wooden pressure bolts, the diameter of the stirrup legs must not fall below a certain level in order to prevent the stirrup legs from being pressed into the wood material under load.

In addition or as an alternative to the construction of the pressure element from steel, the invention provides that sections of the bracket legs are bent towards one another at their free ends with respect to their parallel course. The free ends are thus bent in the plane of the steel bracket. This results in the following advantages, among others:
The anchoring of the stirrup legs in the double-walled shells is increased by the bending, but this is achieved by the semicircular bending of the free ends as in the case of the transport anchor according to FIG DE 297 06 644 U1 has already been achieved. By bending in the plane of the steel bracket, the free ends protrude from the inside of the double-walled shells if their length is suitably dimensioned. As a result, during or after concreting the double wall shells, it can be seen from them how deep the bracket legs are embedded in them. Insufficiently deep embedding can lead to insufficient anchoring the stirrup legs in the shells and above lead to a reduced load-bearing capacity of the lifting anchor. Insufficient concrete cover on the outside of the stirrup legs can lead to the formation of cracks, concrete flaking on the outside and, moreover, to the penetration of moisture into and through the respective wall shell and ultimately to corrosion damage to the reinforcement.

Advantageous refinements of the invention are given in the dependent claims. According to the invention, the pressure element is provided on the front side with recesses through which the bow legs extend.

So that the transport anchor can be handled and mounted as a whole, the pressure element is clamped between the bracket legs and / or fixed by means of welding technology. However, this tacking must not be so strong that there is a connection between the pressure element and the bracket legs that is rigid under the loads to be absorbed. The desired possible deformation of the bracket legs under load in the area of the pressure element can be additionally facilitated by inserting a thin, only a few millimeters thick layer made of a material that is softer than steel, in particular made of a plastic material.

The pressure element can be tubular. In this case it is preferred if, for example, at its ends there are openings that are not covered by the bracket legs has, through which concrete can penetrate into its interior and seals it against the passage of water. Other openings could also be provided for this purpose. Alternatively, the tubular pressure element could be sealed against the passage of water in its longitudinal direction by introducing a sealing compound.

The pressure element can be assembled from two pressure element parts and a connecting element. The connecting element can form a thermal barrier. In particular, the connecting element can be made from a fiber-reinforced polyamide. A water stop can be attached to the connecting element, in particular in the form of a projection running around the circumference of the connecting element.

As is also provided in the prior art, the bracket legs can be connected to one another in the region of their free ends by a transverse web. As a result, the bracket legs are held parallel to one another. In addition, the aforementioned clamping pressure can be generated on the pressure element. If the crosspiece engages around the bracket legs in a U-shape and is welded to them, this also serves to reduce the required anchoring length of the bracket legs. The transverse web can also be a profile bar, through bores of which the bracket legs are simply pushed through and are preferably firmly welded into them again.

The curved central section of the steel bracket can be made at least partially flexible. This allows the middle section for hanging the slinging means be brought into a favorable position for this, in particular protruding from the reinforced concrete prefabricated elements, and for the completion of the concrete wall in a favorable position, in particular between the reinforced concrete double walls. The steel bracket can consist of a steel cable. The pressure element can consist of a round or square tube, at the ends of which guide elements are attached through which the steel cable is guided. The steel cable can have anchoring elements which are provided for anchoring in the reinforced concrete double walls. The distance between the pressure element and the curved central section can be at least 150 cm. The steel cable can have a length that can be guided over a length of at least 150cm in the reinforced concrete double walls. The steel cable can have a diameter of between 5mm and 1 2mm.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

eine Ansicht eines erfindungsgemässen Transportankers in einer Stahlbeton-Doppelwand;

Fig. 2

den Transportanker in einer Seitenansicht;

Fig. 3

den Transportanker in einem Teilschnitt (I - I) mit Aufsicht auf drei Ausführungsarten des Druckelements unter a) - c);

Fig. 4a)

den Transportanker in einem weiteren Schnitt (II - II) mit Aufsicht auf einen Quersteg;

Fig. 4b)

den Transportanker im Schnitt (II - II) mit Aufsicht auf einen anders ausgebildeten Quersteg;

Fig. 5

eine Ansicht eines Transportankers mit einem Druckelement welches zwei Teile aufweist, die mit einem Verbindungselement miteinander verbunden sind in einer Stahlbeton-Doppelwand; und

Fig. 6

eine Ansicht eines Transportankers mit einem Stahlbügel, der aus einem Stahlseil besteht in einer Stahlbeton-Doppelwand.

Show it:

Fig. 1

a view of a transport anchor according to the invention in a reinforced concrete double wall;

Fig. 2

the lifting anchor in a side view;

Fig. 3

the transport anchor in a partial section (I - I) with a plan view of three types of pressure element under a) - c);

Fig. 4a)

the transport anchor in a further section (II - II) with a plan view of a crossbar;

Fig. 4b)

the transport anchor in section (II - II) with a plan view of a differently designed crossbar;

Fig. 5

a view of a transport anchor with a pressure element which has two parts that are connected to one another with a connecting element in a reinforced concrete double wall; and

Fig. 6

a view of a transport anchor with a steel bracket, which consists of a steel cable in a reinforced concrete double wall.

WAYS OF CARRYING OUT THE INVENTION

The transport anchor shown in the figures comprises a steel bracket 10 made from a steel rod with a round cross-section and having a curved central section 11 for suspending the attachment means such as a crane hook or a snap hook. On both sides of the middle section 11, bow legs 12, which run parallel to one another in sections, are connected. Their lower, free end sections 13 are bent towards one another. Like this in Fig. 2 can be seen, the steel bracket 10 extends in one plane.

At the upper end of the bracket legs 12, a pressure element 20 is inserted between them. In the area of their free ends, but still there where they run parallel to one another, the bracket legs 12 are connected to one another by a transverse web 30.

The pressure element 20 is made of steel and is, for example, tubular with a rectangular or round cross-section. Like this in Fig. 3 is shown, the pressure element 20 is provided on the front side with recesses 21 penetrated by the bracket legs 12. In Fig. 3a ) the recesses 21 are rounded and lie tightly against the bracket legs 12. In Figure 3b ) the recesses 21 are approximately V-shaped. In Figure 3c ) an intermediate layer 23 made of a material that is softer than steel, in particular a plastic material, is inserted between the pressure element 20 and the bracket legs 12. The depth of the recesses 21 is in Fig.3a ) sized approximately according to the diameter of the bracket legs 12. In Figure 3b ) the pressure element 20 ends approximately at half the diameter of the bracket legs 12. In Fig.3c ) the pressure element 20 protrudes slightly over the bracket legs 12 on both sides. The depth of the recesses 21 is not necessarily correlated with their shape.

In all three types of Fig. 3 the bracket legs 12 are at least not rigidly connected to the pressure element 20, except that they are held in the recesses 21 in a form-fitting manner on three sides. The pressure element 20 can simply be inserted between the bracket legs 12 without further fixation and, for example, be held between them in a clamping manner. It would also be possible as in Figure 3b ) is shown, the bracket legs 12 with the pressure element 20 to be connected by welding stitching 23. However, such a connection or clamping may only be so strong that the handling and assembly of the transport anchor as a whole, but on the other hand certain movements of the bracket legs 12 in the recesses 21 under the loads to be absorbed by the transport anchor as intended, are possible. With the execution type of Fig.3c ) Plastic material 23 additionally present in the recesses 21, these movements are made even easier.

If the pressure element 20 is tubular and wide enough, as assumed above, it is preferred if it has openings 24 at its ends that are not covered by the bracket legs 12, as shown in FIG Fig. 2 can be recognized. In Fig. 3 the lateral inner walls of the three pressure elements 20 are indicated by dashed lines. It can also be seen from this that the pressure elements 20 are open at the end. When the transport anchor is installed in the shells of a double wall, concrete can penetrate into the pressure element 20 through the openings 24, which among other things improves its embedding in the shells. The penetrated concrete can also close the pressure element against the passage of water. For this purpose, a sealing compound could also be introduced into the pressure element beforehand, which may be necessary above all if the pressure element 20 is only small in width, so that openings 24 are only very narrow or possibly not present at all.

Like this in Figure 4a As can be seen, the ends 31 of the transverse web 30 are each bent over in a U-shape and with these bent ends encompass the bow legs 12, whereby they are also firmly welded to them. To this In this way, the aforementioned clamping pressure for clamping the pressure element 20 between the bracket legs 12 can also be generated and maintained. Instead of a rod-shaped transverse web with a round cross-section and bent ends, a profile bar with, for example, a rectangular, L-shaped or U-shaped cross-section could be used, through bores at the end of which the bracket legs 12 are simply inserted and preferably firmly welded again. This can be produced with less effort. Figure 4b shows such a profile bar 30 'with a downwardly open U-shape.

In Fig. 1 two shells 41 and 42 of a reinforced concrete double wall are indicated by dashed lines, so that it can be seen how the transport anchor according to the invention is usually installed in such a double wall. The two inwardly bent end sections 13 each protrude a little out of the shells 41 and 42. It can be seen from them whether the transport anchor is correctly positioned in the double-walled shells 41 and 42 and whether the bracket legs 12 are adequately covered with concrete.

The U-shaped bent ends 31 of the transverse web 30 encompassing the bracket legs 12 or, correspondingly, the material of a profile bar framing the bores, if the welded connection is sufficiently strong, cause additional anchoring or a higher bonded tension of the bracket legs 12 in the double-walled shells 41 and 42, whereby their embedment depth and thus their length can be chosen to be shorter if necessary. If a profile bar is used, it should protrude on all sides by at least 3 mm over the bores or the bracket legs 12. The additional anchoring of the stirrup legs 12 can be particularly advantageous when using smooth steel for the steel bracket 10 of the transport anchor according to the invention, as will be explained below. The bond stress of plain steel is significantly lower than that of conventional rebar steel, so that the stirrup legs 12 must be dimensioned to be relatively long. Due to the additional anchoring, the length of the bracket legs can be reduced by up to 30% if necessary.

Reinforced concrete double walls are usually reinforced with elongated lattice girders. If the transport anchor 20 with the bracket legs 12 has to be installed transversely to the longitudinal extension of the lattice girders, the transverse web 30 is in the way. Either the transverse web 30 must be omitted from the outset for such an installation or, for example, removed by sawing off. In both cases, however, when the double-walled shells are concreted and also afterwards, the inwardly bent ends 13 of the bracket legs 12 can be seen as to whether they are properly embedded in the shells.

Smooth steel of grade S235 is preferably used for the steel shackle of the transport anchor according to the invention. Its diameter is typically in the range 13 mm - 20 mm, in particular 13 mm or 15 mm. When using a higher quality steel, for example grade S255, the diameter could be reduced to 10 mm. A tubular pressure element with a rectangular cross-section with external dimensions of only approx. 20 mm x 20 mm could have a wall thickness of approx. 2 mm. The length of the bent end sections 13 can be between 30 mm and 100 mm. The turn does not have to be at right angles. An obtuse angle between 105 ° and 150 ° is sufficient.

Fig. 5 shows a view of a transport anchor with a pressure element 20, which is assembled from two pressure element parts 201, 202 and a connecting element 203 for the pressure element parts 201, 202. The connecting element 203 has the shape of a cuboid, cuboid openings being formed on two end faces. A first pressure element part 201 is inserted into one of the cuboid openings and a second pressure element part 202 is inserted into the other of the cuboid openings. The materials and dimensions, in particular the material of the connecting element 203 as well as the cross-section and length of the cuboid openings of the connecting element 203, are selected so that the assembled pressure element 20 reliably fulfills the function of achieving a high load-bearing capacity. If, for example, the length of the cuboid openings is chosen to be too short, the pressure element 20 can buckle in the event of great forces.

The connecting element 203 is made of a material which is suitable for forming a thermal barrier between the two pressure element parts 201, 202. The connecting element 203 is made in particular from a fiber-reinforced polyamide.

With one in the Fig. 5 The assembled pressure element 20 shown can thus both achieve a high load-bearing capacity and also produce thermal insulation between the support shells 41, 42.

As in Fig. 5 shown schematically, the connecting element 203 has a water stop 204. The water stop 204 is formed by a projection running around the circumference of the connecting element 203. The dimensions of the projection can be adapted to the desired effectiveness of the water barrier, with a larger projection improving the effectiveness. The water stop 204 reduces or prevents the flow of water along the pressure element 20.

The two pressure element parts 201, 202 can have the same length. However, it is also conceivable that the pressure element parts 201, 202 are of different lengths.

The pressure element parts 201, 202 can simply be plugged into the connecting element 203. An adhesive can also be used to materially connect the pressure element parts 201, 202 to the connecting element 203.

The water stop 204 can be arranged on an axis of symmetry of the connecting element 203. It is conceivable to arrange the water stop 204 asymmetrically in relation to the connecting element 203. The water stop 204 can also be omitted entirely.

The surface of the connecting element 203 is designed in such a way that it is difficult or impossible for concrete or other materials to adhere. This can ensure that the materials adhere to the surface no additional possibility is created for a water flow along the pressure element 20.

Fig. 6 shows a transport anchor with a steel bracket 10, which consists of a steel cable 18. The two ends of the steel cable 18 are guided in the reinforced concrete double walls 41, 42. The middle section of the steel cable 18 is located between the reinforced concrete double walls 41, 42 and protrudes from them. The distance 19 between the middle section of the steel cable 18 and the pressure element 20 is selected such that the steel cable 18 protrudes from the reinforced concrete double walls by at least 150 cm. When transporting the reinforced concrete double walls 41, 42, the steel cable 18 can protrude therefrom to such an extent that no additional steel cables have to be attached in order to attach slings for lifting the reinforced concrete double walls 41, 42 from a transport means and for moving the reinforced concrete double walls 41, 42 from the means of transport to an installation site at which the reinforced concrete double walls 41, 42 are installed. The attachment of additional steel cables of a minimum length from the reinforced concrete double walls 41, 42 may be necessary, for example, due to legal regulations, in order to avoid that a person has to climb the means of transport before lifting the reinforced concrete double walls 41, 42 in order to reach the slings to hang up.

As in Fig. 6 shown schematically, a pressure element 20 is provided, which is arranged next to a central region of the steel cable 18 and holds the two relevant sections of the steel cable 18 at a distance from one another. The steel cable 18 is guided at the ends of the pressure element 20, for example in guides attached to the ends of the pressure element 20. The guides can be eyelet-shaped. The pressure element 20 can be designed as a round or angular tube. The guides can be in the form of short pipe sections. The guides can be welded to the ends of the pressure element 20. In a variant, the guides have the shape of a cylindrical tube, which has a diameter of between 10 mm and 30 mm, preferably 20 mm.

The steel cable 18 preferably has a diameter of between 5 mm and 12 mm. This results in the required flexibility and tensile strength at the same time. The steel cable 18 preferably has a length that it can be poured into the reinforced concrete double walls 41, 42 over a length of at least 150 cm. This results in a firm anchoring of the steel cable 18 in the reinforced concrete double walls 41, 42, as is known in the case of ribbed or profiled reinforcing steel. The ends of the steel cable 18 can additionally be provided with anchoring elements 61, 62 in order to anchor the steel cable 18 in the reinforced concrete double walls 41, 42. The anchoring elements 61, 62 can be designed in the form of thimbles.

The steel cable 18 protrudes 150 cm from the concrete above, so that a worker standing next to the wall can attach the crane hook. The wall height is between 2.5m and 3.0m.

The steel cable 18 is flexible and can be arranged as required so that it is in prefabricated reinforced concrete double walls after the transport anchor has been installed 41, 42 protrudes from the reinforced concrete double walls 41, 42 or that it is located between the reinforced concrete double walls 41, 42. If the steel cable 18 protrudes from the reinforced concrete double walls 41, 42, the attachment of the sling is simplified. If the steel cable 18 is located between the reinforced concrete double walls 41, 42, the completion of a concrete wall by pouring the reinforced concrete double walls 41, 42 is simplified.

REFERENCE LIST

10

Steel bracket

11

Middle section 11

12th

Stirrup legs

13th

End sections of the bracket legs

20th

Printing element

201, 202

two parts of the printing element

21

Recesses

22nd

layer

23

Stitching

24

openings

30th

Crossbar

30 '

Crossbar

31

Ends 31 of the transverse web

41

Double wall shell

42

Double wall shell

50

Connecting element

51

Water stop

18th

Steel cable

19th

Distance between central section and pressure element

61, 62

Anchoring elements

Claims (16)

1. A prefabricated reinforced concrete double wall with at least one transportation anchor comprising: a steel stirrup (10) with a curved middle section (11) for mounting the slinging means and stirrup legs (12) adjoining the latter on both sides and extending in sections parallel to one another, and a compression element (20) that is arranged between the stirrup legs (12) and, under the loads to be supported, is not rigidly connected to them, at least in their longitudinal direction, wherein the compression element (20) is made of steel, and/or that sections (13) of the stirrup legs (12) are bent at their free ends in each case in the direction towards one another with respect to their parallel course, characterized in that the compression element (20) is provided in each case on the end face with recesses (21) penetrated by the stirrup legs (12), and in that the compression element (20) is clamped between the stirrup legs (21) for handling purposes and/or is fixed by a tack weld (23).
2. The reinforced concrete double wall according to claim 1, characterized in that a layer (22) with a thickness of only a few millimeters made of a material softer than steel, in particular a plastic material, is inserted between the compression element (20) and the stirrup legs (12).
3. The reinforced concrete double wall according to claim 1 or 2, characterized in that the compression element (20) is tubular.
4. The reinforced concrete double wall according to claim 3, characterized in that the tubular compression element (20) has, at least at its ends, openings (24) which are not covered by the stirrup legs (12) and through which concrete can penetrate into its interior.
5. The reinforced concrete double wall according to claim 3 or 4, characterized in that by the introduction of a sealing compound, the tubular compression element (20) is sealed in its longitudinal direction against the passage of water.
6. The reinforced concrete double wall according to any one of claims 1 - 5, characterized in that the stirrup legs (12) are connected to each other in the region of their free ends by a transverse bar (30).
7. The reinforced concrete double wall according to any one of claims 1 - 6, characterized in that the compression element (20) is assembled from two compression element parts (201, 202) and a connecting element (203).
8. The reinforced concrete double wall according to claim 7, characterized in that the connecting element (203) forms a thermal barrier, wherein the connecting element (203) is made in particular of fiber-reinforced polyamide.
9. The reinforced concrete double wall according to claim 7 or 8, characterized in that a water barrier (204), in particular in the form of a circumferential projection, is attached to the connecting element (203).
10. The reinforced concrete double wall according to any one of claims 1 - 9, characterized in that the bent middle section (11) of the steel stirrup (10) is designed to be at least partially flexible.
11. The reinforced concrete double wall according to any one of claims 1 - 10, characterized in that the steel stirrup (10) consists of a steel cable (18).
12. The reinforced concrete double wall according to claim 11, characterized in that the compression element (20) consists of a round or angular tube, at the ends of which guide elements are provided, through which the steel cable (18) is fed.
13. The reinforced concrete double wall according to claim 11 or 12, characterized in that the steel cable (18) has anchoring elements (61, 62) provided for anchoring in the reinforced concrete double walls (41, 42).
14. The reinforced concrete double wall according to any one of claims 11 - 13, characterized in that the distance (19) between the compression element (20) and the bent middle section (11) is at least 150 cm.
15. The reinforced concrete double wall according to any one of claims 11 - 14, characterized in that the steel cable (18) has a length such that the steel cable (18) can be fed over a length of at least 150 cm in the reinforced concrete double walls (41, 42).
16. The reinforced concrete double wall according to any one of claims 11 - 15, characterized in that the steel cable (18) has a diameter of between 5 mm to 6 mm.

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