EP3216944B1 - Assembly for reinforcing support structures - Google Patents

Description

Technical area

The invention relates to the field of reinforcement of supporting structures, preferably by applying surface reinforcement, in particular the introduction of forces into the surface reinforcement.

State of the art

Methods to increase the load-bearing resistance of existing load-bearing structures, typically reinforced concrete components, have been used for many years. Often this is done by means of additional reinforcement attached to the surface. Reinforcements made of fiber composite materials that are glued to the surface have largely prevailed. The effectiveness of this surface reinforcement is normally limited by the maximum force that can be transferred from the concrete to the reinforcement.

Various methods for improving the power transmission from the supporting structure to the surface reinforcement are known. A widely used method consists in inserting fiber bundles into a hole in the support structure and anchoring them there and spreading out or fanning out an end of the fiber bundle protruding beyond the surface and gluing it onto the surface. A surface reinforcement can then be glued to the reinforced structure surface. Alternatively, the surface reinforcement can first be glued to the structure surface so that when an anchor made from a fiber bundle is attached afterwards, the protruding end of this is glued to the surface of the surface reinforcement. In the case of surface reinforcement with several layers, it is often recommended to spread the anchors between the fabric layers for better power transmission.

The effectiveness of this measure has been proven experimentally, but remains limited for various reasons.

On the one hand, the potential fracture surface near the surface is only broken through by each anchor at one point (on the shaft). The resistance of this potential fracture surface is only increased to a limited extent. On the other hand, the power transmission from the fibers of the fiber bundle spread out on the surface to the fibers of the fabric is not optimal. The very thin fiber composite material formed by the fibers of the fiber bundle on the surface can only be significantly loaded in the tensile direction. When subjected to pressure, the fiber composite material kinks; when subjected to shear and bending, only very small forces can be transmitted. Therefore, only the fibers lying approximately in the tensile direction of the surface reinforcement are fully effective. These make up only a small part of the fiber bundle cross-section and only cover a small part of the width of the surface reinforcement.

Another disadvantage of the known method is that the end of the fiber bundle protruding over the surface is spread out on the surface itself and is thus caused by protrusions, protruding deformations on the surface, which on the one hand can disturb the appearance of a building, but on the other hand also technical Can have disadvantages. For example, elevations in an otherwise flat surface can lead to water, in particular rainwater, or snow, but also dirt, accumulating on these elevations and impairing the long-term effect.

US 6,324,805 B1 discloses an arrangement having the features of the introductory part of claim 1.

Presentation of the invention

The object of the present invention is therefore to provide an arrangement according to which an improvement in the introduction of force into a surface reinforcement is to be achieved.

Furthermore, it is the object of the present invention to improve the power transmission of fiber bundles which are attached to a supporting structure, in particular in a surface area or in an area close to the surface.

It has surprisingly been found that this object can be achieved by means of an arrangement according to claim 1.

The essence of the invention is accordingly an arrangement comprising a support structure with a surface consisting of several surfaces, with a bore running from one surface into an inner area of the support structure, and this bore is filled with an adhesive and with a section of a fiber bundle protruding beyond this bore is, wherein the support structure is provided on the one surface from which the bore extends into an inner region of the support structure with at least one groove which extends from the bore in at least one direction on the surface and the protruding part of the Fiber bundle is at least partially located in the at least one groove and is fixed therein with the adhesive.

An element or part of an element that is exposed to forces is referred to here as a support structure. The supporting structure is typically a building or a component part of a building, for example a plate, a ceiling, a wall, a column, a rib, a beam or the like. The supporting structure typically consists of concrete, in particular reinforced concrete, but can also consist of bricks or other bricks, wood, steel or other materials and any combination of these materials. Typically, the structures are civil engineering structures such as houses, bridges, tunnels, dams, sports facilities, etc.

The fiber bundle is a loose arrangement of essentially unidirectional individual fibers or filaments, in particular made of carbon, glass, basalt, aramid, steel or other inorganic or organic materials. The fibers are preferably carbon fibers.

The strength of the fiber bundle depends on the area of application and the forces that are to be transmitted through the fiber bundle. If the fiber bundle consists of carbon fibers, it comprises in particular 1000 to 50,000 individual fibers, each of which has a diameter in the range from 5 to 10 µm. A typical fiber bundle preferably has a cross-sectional area of 20 to 70 mm ² , in particular 25 to 40 mm ² .

The attachment of the fiber bundle to the support structure typically takes place in that, in a first step, a bore is made at the desired location, which hole serves to receive a section of the fiber bundle. The bore can be created by any means, such means being very well known to the person skilled in the art. The dimensions of the bore result from the strength and the length of the fiber bundle and these in turn from the requirements which are placed on the arrangement according to the invention. A suitable bore typically has a diameter of 1 to 5 cm, in particular 1.5 to 3 cm, and a depth of 5 to 30 cm, in particular 7 to 20 cm.
In a further step, starting from the bore or from the entry point of the bore into the surface of the support structure, one or more grooves are made. The grooves can also be created by any means, for example with an angle grinder.
The groove or grooves are dimensioned in such a way that they can accommodate the fiber bundle in their entirety, which can be divided into individual fiber strands in the event that several grooves are present.
The number and arrangement of the grooves is dependent on the area of application of the arrangement according to the invention.

After the bore and the at least one groove have been made, the fiber bundle is inserted into the bore and groove and glued therein. For this purpose, an adhesive is first introduced into the bore and into the at least one groove. The fiber bundle, which is preferably impregnated with a resin beforehand, is then introduced into the bore in such a way that a section of the fiber bundle protrudes beyond the bore. In the course of the attachment of the arrangement according to the invention to a supporting structure, the section of the fiber bundle protruding beyond the bore usually also protrudes beyond the surface of the supporting structure. The section of the fiber bundle which, however, is located in a groove in the assembled arrangement, then does not protrude more beyond the surface of the supporting structure, whereby a uniform and smooth surface can be guaranteed.

This protruding section of the fiber bundle is at least partially inserted into the groove provided with adhesive or evenly divided into a number of fiber strands corresponding to the number of grooves and inserted into the grooves. Most preferably, the entire fiber bundle or all fiber strands are inserted into one or more grooves, so that the fiber bundle does not protrude at any point beyond the surface of the support structure. After the fiber bundle has been inserted into the at least one groove, the fiber bundle can be pressed into it. Adhesive that oozes out of the borehole or from the groove is then removed or evenly distributed in the area of the surface affected by the arrangement. If there are still cavities in the bore or in the at least one groove after the fiber bundle has been inserted, these can be filled with adhesive.
The fiber bundle is introduced into the bore in particular with a needle-like object. For better guidance with the needle-like object, a clamp, a cable tie or the like, on which the needle-like object can be hooked, can be attached to the fiber bundle.
Impregnating the fiber bundle with a resin before inserting it into the bore and groove has the advantage that the entire fiber bundle can be wetted with resin, even in the inner area. To ensure optimal adhesion between the fiber bundle and the support structure, the resin for impregnating the fiber bundle has, in particular, the same chemical basis as the adhesive for fastening the fiber bundle in the bore and groove. In particular, both the resin and the adhesive are epoxy resin compositions. It is possible for the adhesive and the resin to have the same composition, the viscosity of the resin typically being set somewhat lower than that of the adhesive, which in turn serves to improve the wetting of the fibers.

A two-component epoxy resin composition is preferably used both for the adhesive for fastening the fiber bundle in the bore and groove and for the resin for any impregnation of the fiber bundle. Suitable epoxy resin compositions are, for example, commercially available under the trade name Sikadur® from Sika Schweiz AG.

The bonding points on the supporting structure are preferably clean, dry, and free of dust and grease. Depending on the materials from which the supporting structure is made, suitable cleaning measures or pretreatments can be applied.

The arrangement according to the invention can be attached to a support structure for different purposes. In particular, the arrangement itself serves as a reinforcement for the supporting structure and / or it serves as an anchor or anchoring for a surface reinforcement attached to the supporting structure.

In a further embodiment, the arrangement itself can serve to reinforce a supporting structure. In this case, in particular, several of the arrangements described are attached to a support structure at regular intervals. In this case as well, the arrangement according to the invention can have a plurality of grooves, as described above. According to the invention, the arrangement has a second bore which runs into the inner region of the support structure, the second bore being on a different surface of the surface. The at least one groove runs from the entry point of the one, i.e. the first, bore along the surface the support structure to the entry point of the second bore, the two bores are therefore connected to one another in the surface area of the support structure via the at least one groove. Since the two bores are not located on the same area of the surface of the support structure, i.e. there is or are one or more edges between the surfaces, the at least one groove also runs over these edges. According to the invention, the two bores are located on mutually opposite surfaces of the support structure, and the two bores are connected to one another in the extension of their respective drilling axes.

This is the case, for example, when the arrangement according to the invention is to be attached in the area of the end face of a wall that is free on at least one side. In this case, the two holes can be created by drilling through the wall in one place. A groove is then made in particular in such a way that it connects the entry point and the exit point of the bore in the wall with one another across the end face. The exit point of one hole in the wall represents the entry point of the second hole.

Even with such a use of the arrangement according to the invention, a surface reinforcement can be attached to the surface of the supporting structure.

Regardless of the nature of the arrangement according to the invention, the surface reinforcement is preferably attached in such a way that it extends in at least one groove on the surface of the supporting structure Section of the fiber bundle and the hole or the entry point of the hole in the surface covers as a whole and is glued to the surface of the support structure over this entire area.

Particularly suitable surface reinforcement are lamellae or fabric which run along the surface of a supporting structure and are glued to it, in particular over the entire area. Particularly suitable slats are unidirectional fiber-reinforced plastic flat strip slats. The fiber reinforcement is usually done with carbon fibers, but like with the fiber bundle, it can also be done with glass, basalt or aramid. In particular, an epoxy resin matrix is used as the plastic matrix. A plastic matrix can likewise suitably be based on polyurethane, vinyl ester, polyacrylate or other compositions which have structural properties. Suitable fiber-reinforced plastic flat strip lamellae are commercially available, for example, under the trade name Sika® CarboDur® from Sika Schweiz AG.
A carbon fiber fabric, in particular a unidirectional one, is preferably suitable as the fabric, it also being possible for this to consist of glass, basalt or aramid fibers. In contrast to the fiber-reinforced plastic flat strip lamellas, the fabric is typically not already applied to the surface in a hardened plastic matrix, but provided with a hardenable composition before or after it is attached to the surface. The curable composition is in particular an epoxy resin composition, in which case polyurethane or polyacrylate could also be used here.
A carbon fiber fabric such as is commercially available from Sika Schweiz AG, for example under the name SikaWrap®, is particularly suitable as the fabric.

Both as a plastic matrix for the fiber-reinforced plastic flat strip lamellae and for gluing these or the fabric to the supporting structure are preferably two-component Epoxy resin compositions used, such as are commercially available, for example, under the trade name Sikadur® from Sika Schweiz AG.

As already described above, the fiber bundle runs in the at least one groove over edges which connect different areas of the surface of the support structure to one another. This edge preferably has a rounding in the interior of the groove. The radius of the rounding is in particular about 0.5 to 10 cm, in particular 1 to 5 cm.
The rounding of the edge protects the fiber bundle that is inserted in the bore and groove, which means that there are fewer fiber breaks and improved power transmission is possible. Most preferably, regardless of the particular embodiment of the present invention, all edges of the support structure over which a groove with a fiber bundle is to run are rounded within the groove.
Furthermore, it is also possible that the transition from the bore into the groove also has a rounding as described above.

The arrangement according to the invention is typically used in the reinforcement of existing supporting structures, for example in renovation, repair or in the case of earthquake reinforcement subsequently attached to supporting structures. If the supporting structure is a reinforced concrete structure, the reinforcement takes place, for example, where the steel reinforcement is inadequate or where it has been damaged by an unforeseen event.

Brief description of the drawings

With the aid of the drawings, both inventive and non-inventive embodiments are explained in more detail. The same elements are provided with the same reference symbols in the various figures. It goes without saying that the invention is not restricted to the exemplary embodiments according to the invention that are shown and described, but rather only by the appended claims.

• Figuren 1A bis 2C (nicht erfindungsgemäß): Tragstrukturen mit Bohrungen und Nuten und darin eingeklebten Faserbündeln bzw. Fasersträngen;
• Figuren 3A bis 4B (nicht erfindungsgemäß): Tragstrukturen mit Bohrungen und Nuten und darin eingeklebten Faserbündeln bzw. Fasersträngen sowie Oberflächenbewehrung;
• Figuren 5A, 5B und 6F (nicht erfindungsgemäß) und
• Figuren 6A, 6B, 6C, 6D, 6E und 6G (erfindungsgemäß): Ausführungsformen von Tragstrukturen mit Bohrungen und Nuten und darin eingeklebten Faserbündeln bzw. Fasersträngen;
• Figuren 7A und 7B (erfindungsgemäß, das Faserbündel und der Kleber in der Nut und den Bohrungen ist jedoch nicht dargestellt): Detailansichten von Tragstrukturen mit abgerundeten Kanten innerhalb der Nut.

Show it:

• Figures 1A to 2C (not according to the invention): support structures with bores and grooves and fiber bundles or fiber strands glued into them;
• Figures 3A to 4B (not according to the invention): support structures with bores and grooves and fiber bundles or fiber strands glued into them, as well as surface reinforcement;
• Figures 5A, 5B and 6F (not according to the invention) and
• Figures 6A, 6B, 6C, 6D, 6E and 6G (according to the invention): Embodiments of support structures with bores and grooves and fiber bundles or fiber strands glued into them;
• Figures 7A and 7B (according to the invention, but the fiber bundle and the adhesive in the groove and the bores are not shown): Detailed views of support structures with rounded edges within the groove.

In the figures, only the elements essential for a direct understanding of the invention are shown.

Figure 1A shows a section through a support structure 1 with a surface consisting of several surfaces 2a, 2b, 2c, with a bore 3 extending from surface 2a into an inner region of the support structure. This bore is filled with an adhesive 12 and with a portion of a fiber bundle 4 protruding beyond this bore Face extends in one direction on the surface. The part of the fiber bundle 4 protruding beyond the bore is located in the groove 5 and is fastened therein with adhesive 12.

Figure 1B shows a top view of the in Figure 1A The arrangement shown, not according to the invention, wherein a single groove 5 extends from the bore 3 in one direction on the surface. Furthermore, the entire protruding part of the fiber bundle is located in the groove and is fastened therein with adhesive 12.

Figure 1C also shows a plan view of the in Figure 1A arrangement shown, wherein in this embodiment several grooves 5 extend from the bore 3 in different directions on the surface. The protruding part of the fiber bundle 4 is divided into fiber strands, these fiber strands preferably having approximately the same thickness, and the fiber strands are located in the grooves and are fixed therein with adhesive 12.

Figures 2A and 2B shows essentially an analogous embodiment not according to the invention as shown in FIGS Figures 1A and 1C is shown, wherein the plurality of grooves 5, starting from the bore 3, extend radially on the surface of the support structure 1.

Regardless of the above-described non-inventive embodiments, the section of the fiber bundle which is located in the bore is in particular one of the two loose ends of the fiber bundle. The other loose end of the fiber bundle represents that part of the fiber bundle which protrudes beyond the bore or which is located in the groove or the grooves and is attached there.

In another, less preferred embodiment not according to the invention, it is also possible to fold over a fiber bundle in particular in the area of its center or its geometric center of gravity and thus to place the two loose ends of the fiber bundle on top of one another. Then the fiber bundle is then inserted into the bore, preferably with the folded end, and the two loose ends are inserted into the groove or divided into several grooves. In both cases, the section of the fiber bundle which is located in the bore is in particular approximately the same length as that which protrudes beyond the bore.

Figure 2C shows an embodiment not according to the invention, in which a central section of the fiber bundle is located in the bore. The support structure 1 shown here has a surface consisting of several surfaces 2a, 2b, 2c, etc. and a first bore 3a, which extends from the surface 2a into the inner region of the support structure. The second bore 3b runs from the surface 2b into the inner region of the supporting structure. The surface 2b faces away from the surface 2a and the two bores 3a and 3b are arranged in such a way that they are connected to one another in the extension of their respective drilling axes. Of course, in the case shown, the two bores can be created in that the support structure is pierced from a surface and the second bore thus represents the exit point of the first bore. The holes 3a and 3b are with an adhesive 12 and filled with a section of a fiber bundle 4. In particular, this

Embodiment a fiber bundle is arranged in the bore in such a way that its central section is located in the bore and that its loose ends each protrude beyond the surface of the support structure. A plurality of grooves 5 each extend from the bores 3a and 3b in different directions on the surface, for example in the manner as shown in FIG Figure 2B is shown. The protruding parts of the fiber bundle 4 are divided into fiber strands and the fiber strands are located in the grooves and are fixed therein with adhesive.

In the Figures 3A (Cross-section) and FIG. 3B (top view) shows an embodiment of the arrangement which is not according to the invention. A surface 2a of the surface of a support structure 1 has several bores 3, which run into the inner area of the support structure 1, and a single groove 5 for each bore, which extends along the surface (see also FIG Figure 1B ). The bores 3 and the grooves 5 are offset from one another, but in their entirety are attached linearly to the surface. A lamella 6 is attached as surface reinforcement over the grooves 5 with the sections of the fiber bundles 4, this lamella being glued to the surface of the supporting structure at least in this area. In particular, such a lamella is glued over the entire surface to the surface of the support structure. Arrangements like those in the Figures 3A and 3B shown, occur in particular in the area of the end sections, for example in the last 0.5 to 1 meters, of the lamellas and serve to improve the transmission of force between the supporting structure and the lamella, i.e. surface reinforcement.

Figure 3C FIG. 11 shows a plan view of an arrangement not according to the invention, which is essentially that of FIG Figure 1C corresponds, with a fabric 7 being attached as surface reinforcement over the grooves 5, which extend from the bore 3 and are provided with fiber strands of the fiber bundle 4 and with adhesive. Such a fabric is also preferably glued over the entire area to the surface of the support structure. The gluing of the fiber bundle glued into the grooves leads to an improved transmission of force between the supporting structure and the fabric, that is to say the surface reinforcement.

An embodiment of the arrangement not according to the invention as shown in FIGS Figures 1C and 3C shown is still in the Figure 3D shown. In this case, the bore 3, which runs into the inner area of the supporting structure, is located at a joint between two flat elements of a supporting structure, for example at a joint between two walls or between wall and base plate. In this case too, a surface reinforcement in the form of a fabric 7 is attached over the anchor area.

Another embodiment not according to the invention is shown in FIG Figure 3E shown. The support structure 1 shown here has a surface consisting of several surfaces 2a, 2b, 2c and a first bore 3a, which extends from the surface 2a into the inner region of the support structure. The second bore 3b runs from the surface 2b into the inner region of the supporting structure. The surface 2b faces away from the surface 2a and the two bores 3a and 3b are arranged in such a way that they are connected to one another in the extension of their respective drilling axes. Of course, in the case shown, the two bores can be created in that the support structure is pierced from a surface and the second bore thus represents the exit point of the first bore. The bores 3a and 3b are filled with an adhesive (not shown) and with a section of a fiber bundle 4. In particular, in this embodiment a fiber bundle is arranged in the bore in such a way that its central section is located in the bore and that its loose ends each protrude beyond the surface of the support structure. A plurality of grooves 5 each extend from the bores 3a and 3b in different directions on the surface. The protruding parts of the fiber bundle 4 are divided into fiber strands and the fiber strands are located in the grooves and are fixed therein with adhesive. A fabric 7 is attached over the described arrangements, which runs over the end face of the support structure and is glued to the support structure in the area of the grooves running from the entry point of the bore 3a to that of the bore 3b.

An embodiment not according to the invention, in which two bores are also present, which are connected to one another in the extension of their drilling axes, is in the Figures 3F (Cross-section) and 3G (top view). Here, a T-shaped support structure with a surface comprising a plurality of surfaces 2a, 2b, etc. at the joint between its two flat elements has two bores 3a and 3b which connect the surfaces 2a and 2b to one another. The fiber bundle 4 is arranged in the bore in such a way that its central section is located in the bore and that its loose ends each protrude beyond the surface of the support structure. Several grooves 5 each run in different directions on the surface from the bores. The protruding parts of the fiber bundle 4 are divided into fiber strands and the fiber strands are located in the grooves and are fixed therein with adhesive. In the Figures 3H and 3I is one possible application of the Figures 3F and 3G shown arrangement not according to the invention. The supporting structure 1 is a concrete slab 10 which has several reinforcing ribs 11, that is to say T-shaped sections. The reinforcement ribs 11 had holes 3 in the area of their abutment points with the concrete slab 10, these being laid out in such a way that two holes in each case are connected to one another in the extension of their drilling axes. Starting from the entry point of the respective borehole 3, several grooves run along the surface of the concrete slab. Analogously to the above-described embodiments not according to the invention, boreholes and grooves are filled with a fiber bundle or with fiber strands of the fiber bundle and adhesive. A surface reinforcement in the form of a fabric 7 is attached over the surfaces of the concrete slab, which are located between the reinforcement ribs 11. In particular, this fabric is glued over the entire surface to the underlying surface.

In the Figures 4A (Cross-section) and 4B (top view) shows a further embodiment not according to the invention, in which arrangements, such as are for example in FIGS Figures 2A and 2B are shown, are attached to a support structure 1 at regular intervals. The arrangements can be attached to one area of the surface of the support structure or to several areas. Above the arrangements, a fabric 7 is also glued at least to the arrangements, but in particular over the entire area, to the surface of the support structure. The fabric can run continuously over corners and edges in the surface of the support structure.

Figure 5A shows a section through an embodiment not according to the invention of an arrangement with a support structure 1 with a surface consisting of several surfaces 2a, 2b, 2c, etc. and a first bore 3a, which runs from the surface 2a into the inner area of the support structure. The second bore 3b runs from the surface 2b into the inner region of the supporting structure. The surface 2b faces away from the surface 2a. A groove 5 runs from one bore 3a along the surface of the support structure to the point of entry of the other bore into the support structure. The groove, which thus connects the two entry holes of the bores with one another, runs in particular on the shortest path between the two bores. Depending on the requirements for the reinforcement of the support structure, however, it is also conceivable that the groove takes a different course between the bores, for example in order to ensure the most uniform possible force distribution. A fiber bundle 4 runs in the groove 5, which ends with its loose ends in the two bores 3a and 3b. Both the bores and the groove contain adhesive 12 for fastening the fiber bundle. A similar embodiment not according to the invention as in FIG Figure 5A is also in Figure 5B shown, the fiber bundle here wrapping around a reinforcing rib 11 of a supporting structure 1.

Figure 6A shows a section through an embodiment according to the invention, which is a modification of the embodiment not according to the invention Figure 5A is equivalent to. In contrast to this, the embodiment in Figure 6A two bores 3a, 3b in different, mutually facing away surfaces 2a, 2b of the surface of the support structure, the two bores 3a and 3b being arranged so that they are connected to one another in the extension of their respective drilling axes. The entry holes of the two Bores 3a and 3b are as in Figure 5A connected to one another via a groove 5. Both the bores 3a, 3b and the groove 5 contain an adhesive 12 and a fiber bundle 4. The fiber bundle is in particular arranged in such a way that its two ends overlap. This overlap can be in the bore or at any point in the groove. The length of the overlapping area of the fiber bundle is in particular selected in such a way that the transmission of force as seamless as possible is guaranteed and is approximately 5 to 50 cm. Depending on the requirements placed on the support structure, it is also possible to wrap the fiber bundle several times around the support structure. With respect to the embodiments of the invention as set forth in FIGS Figures 6A to 6D are shown, the two bores 3a and 3b are arranged so that they are connected to each other in the extension of their respective drilling axes, and the fiber bundle can be arranged so that its two ends at least overlap. As a result, the fiber bundle forms a closed loop, as a result of which the transmission of the thrust force takes place between the two ends of the fiber bundle, i.e. within the same material, which is critical for contact. Compared to embodiments in which the ends of the fiber bundle are inserted in separate bores and the shear force is thus transmitted between the support structure and the fiber bundle, i.e. in a critical manner, the preferred embodiments allow a higher efficiency of the reinforcement and a significantly better utilization of the fiber bundle.

the Figures 6B and 6C show modifications of the embodiment according to the invention as shown in FIG Figure 6A is described. Arrangements according to the invention are shown here, such as can be used, for example, to reinforce a rectangular column as part of a support structure. Figure 6C shows that it is also possible for the fiber bundle 4 to be guided several times through a bore, but to run in two different grooves from the entry point of the first bore to that of the second bore. on the other hand can make the embodiment Figure 6C can also be created by the part of the fiber bundle protruding beyond the bore is divided into two fiber strands, which then run in different grooves.

Figure 6D shows a modification of the embodiment shown in FIG Figure 5B is shown, the fiber bundle 4 completely wrapping around the reinforcing rib 11 here.

Figure 6E FIG. 11 shows a side view of a support structure which the in FIGS Figures 6A, 6B and 6C includes variants of the arrangement according to the invention shown. Depending on the requirements, the different variants can be combined with one another or several identical arrangements can be attached to a supporting structure.

Figure 6G shows support structure 1 comprising a base plate 10 and a wall created thereon, the wall being provided in its lower area with several arrangements according to the invention, which consist of those from Figure 6A correspond. Optionally, a fabric for additional reinforcement of the supporting structure can be attached via these arrangements (not shown here).

Figure 6F shows a cylindrical column which comprises several arrangements not according to the invention.

Figure 7A shows a detailed view of a section of a support structure 1 with a surface consisting of several surfaces 2a, 2b, 2c, with a bore 3 extending from one surface 2a into an inner region of the support structure. The support structure 1 is provided with a groove 5 on the surface 2a, from which the bore extends into an inner region of the support structure, which, starting from the bore, extends in one direction on the surface.

The groove 5 runs over an edge 8, which connects the two surfaces 2a and 2c, or 2c and 2b of the surface of the supporting structure with one another, and this one edge 8 has a rounding 9 inside the groove 5. Figure 7B shows a section through a region of a support structure 1, which has two bores 3a, 3c in different, mutually facing away surfaces 2a, 2c of the surface of the support structure, the two Bores 3a and 3c are arranged so that they are connected to one another in the extension of their respective drilling axes. The entry holes of the two bores 3 a and 3 b are connected to one another via a groove 5. Within the groove 5, the edges 8 each have a rounding 9. Here, too, the respective transitions from the bore into the groove can have a rounding according to the preceding description.

Examples

Embodiments not according to the invention are listed below.

Test specimen

Concrete cubes with an edge length of 20 cm were produced as test specimens, with concrete from the same batch being used for all cubes. The concrete cubes were stored for 28 days at 23 ° C and 50% relative humidity. The concrete cubes were sanded down on one side to remove cement slurry. A hole with a diameter of 20 mm and a depth of 100 mm was made in the center of the treated area. Two concrete cubes were left without drilling. Starting from the borehole, eight grooves were made evenly around the borehole with an angle grinder on the concrete cubes. The grooves were 5 mm wide and 5 mm deep and extended over a length of 8 cm. The angle between the grooves was 45 ° in each case. In the case of four concrete cubes, only five grooves were made in a semicircle. The edges at the transition from the hole to the grooves were slightly rounded. No grooves were made for two cubes. The concrete cubes were then repeatedly cleaned on the machined surface and inside the bore with compressed air and a brush, and thus largely freed of dust.

Sikadur®-330, commercially available from Sika Schweiz AG, with an average layer thickness of approx. 1 mm was applied to the machined surface of the concrete cubes without drilling. With the concrete cubes The bore was filled with Sikadur®-330 from the bottom up and the grooves. Care was taken to ensure that no air was trapped in the borehole.

A fiber bundle with a length of 20 cm and a fiber cross-sectional area of about 25 mm ² was completely impregnated with Sikadur® 300 from Sika Schweiz AG using a brush. A cable tie was then attached to a loose end of the impregnated fiber bundle, tightened and cut to length. With the help of a knitting needle, which was hooked into the cable tie, the fiber bundle was inserted into the hole as far as it would go. The protruding end of the fiber bundle was divided into fiber strands, whereby the number of fiber strands had to correspond to that of the previously made grooves, and placed in the grooves. In the case of the concrete cubes without grooves, the protruding end of the fiber bundle was evenly fanned out and spread over the machined surface of the concrete cube.

The Sikadur®-330 fiber bundle was then evenly distributed over the grooves on the processed surface of the concrete cube, so that the entire processed surface was covered with sufficient adhesive.

A fabric made of SikaWrap® 300 C NW (width 20 cm, length 180 cm) provided was laminated with Sikadur®-300 in the area of the last 20 cm of its loose ends using a paint roller. A laminated loose end was placed on the machined surface of the concrete cube and pressed there with a paint roller. Sikadur®-330 was applied over the attached tissue using a notched trowel. The fabric was put in a loop and the other loose and laminated end was placed on the same spot on the concrete cube so that the two ends of the fabric lay on top of each other. Again the fabric was pressed on with the paint roller. Excess adhesive was removed from the test specimen with a spatula the width of the concrete cube.

The test specimens produced in this way were left at 23 ° C. and 50% relative humidity for 7 days so that the adhesive could cure.

Test specimens with fiber bundles made of glass fibers with a fiber cross-sectional area of about 25 mm ² were also produced in the same way.

Two identical test specimens of each type were produced. The results of the measurements represent the mean value of the measurements on the two identical test specimens.

Measurement method

The tensile shear strength of different test specimens was measured according to ISO 527-4 / EN 2561 with a measuring speed of 2 mm / min at 23 ° C. and a relative humidity of 50%.

The tensile shear strength of the bond was tested by placing the loop formed by the SikaWrap-300C NW fabric around a steel tube connected to the movable frame of the testing machine. The concrete cube was connected to the fixed frame of the testing machine via a steel crossbeam and threaded rods.

Results

drilling Grooves (number) Material fiber bundle Maximum load (kN) Mean value (kN) no No - 36.1 37.1 40.3 34.9 Yes No Carbon fiber 47.6 44.6 39.0 47.2 Yes No glass fiber 54.9 52.6 50.6 52.2 Yes 8th Carbon fiber 61.9 64.3 66.8 64.3 Yes 8th glass fiber 70.9 63.8 56.8 63.7

List of reference symbols

1

Support structure

2

Surfaces (2a, 2b, 2c)

3rd

Bore (3a, 3b, 3c)

4th

Fiber bundles or fiber strands

5

Groove

6th

Lamella

7th

tissue

8th

Edge

9

Rounding off

10

Concrete slab

11

Reinforcement rib

12th

adhesive

Claims (5)

1. Arrangement comprising a supporting structure (1) with a surface consisting of a plurality of faces (2a, 2b, 2c), wherein a bore (3) runs from one of the faces into an inner region of the supporting structure (1), and said bore (3) is filled with an adhesive (12) and with a portion of a fibre bundle (4) protruding beyond said bore (3), wherein the supporting structure (1) on the one face (2a) from which the bore (3) runs into the inner region of the supporting structure (1) is provided with at least one groove (5) which, proceeding from the bore (3), extends in at least one direction on the surface, and the protruding part of the fibre bundle (4) is at least partially situated in the at least one groove (5) and is fastened in the latter with an adhesive (12), wherein a second bore (3b) runs from another face (2b, 2c) of the surface of the supporting structure (1) into the inner region of the supporting structure (1), and the at least one groove (5) runs from the point of entry of the one bore (3a) along the surface of the supporting structure (1) to the point of entry of the second bore (3b), wherein the protruding portion of the fibre bundle (4) runs at least partially in the at least one groove (5) and opens into the second bore (3b) and is fastened in the latter with an adhesive (12),
   characterized in that
   the other face is a face that faces away from the one face, in that the two bores (3b) in the extension of the respective bore axes thereof are connected to one another, and in that the groove (5) runs across at least one edge (8) which connects the two faces of the surface of the supporting structure (1) to one another.
2. Arrangement according to one of the preceding claims, wherein this at least one edge (8) has a rounded portion (9) in the interior of the groove (5).
3. Arrangement according to one of the preceding claims, wherein the surface of the supporting structure (1) is at least partially connected to at least one surface reinforcement, in particular to a lamella (6) and/or to at least one woven fabric (7), wherein the surface reinforcement, at least in the region of the fibre bundle (4) which has been fastened in the groove (5) by means of an adhesive (12), is adhesively bonded to the surface of the supporting structure (1).
4. Arrangement according to one of the preceding claims, wherein the fibre bundle (4) is disposed such that the two ends thereof at least overlap, the fibre bundle (4) forming a closed loop.
5. Arrangement according to Claim 4, wherein a length of the overlapping region of the fibre bundle (4) is 5 to 50 cm.

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