System for reinforcing a supporting structure element of a building

Abstract

In order to reinforce a supporting structure element (2) such as a floor, a floor slab or a beam of a building, in particular retroactively, the invention proposes fastening a bracket (5), for example made of structural steel, having threaded rods (7) which are mortared into holes (8) in the supporting structure element (2), in particular on an underside of the supporting structure element (2). An anchoring depth (Ti) of the fastening elements (6) is approximately 90-95% of the thickness of the supporting structure element (2).

Description

[0001] Description

[0002] System for strengthening a structural element of a building

[0003] The invention relates to a system for reinforcing a structural element of a building structure having the features of the preamble of claim 1.

[0004] A building's supporting structure is a construction that provides mechanical stability to the structure. It can be part of the structure. The structure as a whole can also be the supporting structure, or it can form a supporting structure. A structural element is an element of the supporting structure, for example, a building ceiling, a floor slab, a wall, or a beam.

[0005] To reinforce a bridge, for example, the published patent application DE 10 2014 214 473 A1 proposes attaching a tab made of metal or, for example, carbon fiber with screws, for example concrete screws, to an underside of the bridge, i.e. in a tensile zone.

[0006] The object of the invention is to improve the reinforcement of the structural element of such a system.

[0007] This object is achieved according to the invention by the features of claim 1. The system according to the invention for reinforcing a structural element of a building has a plate which is fastened to the structural element by means of fastening elements and rests flat against a surface of the structural element. The structural element is made in particular of reinforced concrete. The plate is a strip-shaped element, i.e. its thickness is only a fraction of its width and length and it is preferably several times as long as it is wide. The thickness of the plate is, for example, a maximum of 20% and in particular a maximum of 10% of the width, or the plate is between 5 and 15 mm thick. The width of the plate is, for example, between 100 and 300 mm, preferably between 180 and 220 mm and in particular 200 mm. The plate is in particular at least twice and preferably at least 5 to 10 times as long as it is wide. In particular, the plate is made of steel.

[0008] "Face-to-face contact" means that the tab rests against the surface of the structural element with one of its two large sides, with the large sides of the tab extending in a longitudinal and a transverse direction of the tab. The tab does not have to rest against the surface of the structural element with its entire surface; rather, there may be gaps within a contact surface between the tab and the structural element. "Face-to-face contact" also includes the case where there is an adhesive layer between the tab and the surface of the structural element, for example, for temporary attachment until the binder, explained below, hardens.

[0009] The surface of the structural element against which the tab rests is preferably flat or straight in the longitudinal direction of the tab, but can also be convexly curved. A concave surface is less suitable for attaching the tab, but is not excluded by the invention.

[0010] In particular, the strap is attached to the structural element in or on a tensile zone. The tensile zone is subjected to tensile stress when the structural element is loaded, for example, by its own weight and / or by externally applied or acting loads. The tensile zone is predominantly an underside, i.e., a downward-facing side of the structural element.

[0011] The fastening elements are each anchored, i.e. fastened, in a hole in the structural element, wherein the holes are in particular drilled, i.e. drilled holes. The holes are - regardless of how they are manufactured - preferably cylindrical, but can also have one or more undercuts or basically any shape. The holes preferably run perpendicular to the surface of the structural element to which the tab is attached, whereby an angular deviation of up to 10°, preferably a maximum of 5°, is possible. Likewise, holes in the structural element for the fastening elements can be drilled at an angle of, for example, up to approximately 40 - 50° to the surface to which the tab is attached, i.e., holes at an angle of 45°.

[0012] The fastening elements can be screwed into the holes. In particular, however, the fastening elements are secured in the holes with a hardened binding agent such as adhesive, plastic, synthetic resin, mortar or the like. The binding agent is processed in particular in a flowable form, for example in a viscous, pasty state, and hardens in the holes in the structural element such that it secures the fastening elements in the holes. The connection can be material-fit and / or form-fit. The binding agent can comprise one or more components. In addition to being fastened with the binding agent, the fastening element can be screwed into the hole in the structural element. However, it is also possible to fasten the fastening elements exclusively with the binding agent, even if the fastening elements have threads.

[0013] The invention provides a relatively deep or long anchoring depth of the fastening elements in the structural element. The anchoring depth is a length of a longitudinal section of the fastening elements located in the respective hole or in the structural element. In particular, the anchoring depth of the fastening elements in relation to a thickness of the structural element is decisive, i.e., to a dimension of the structural element in the region of the respective hole perpendicular to the surface of the structural element to which the tab is attached. According to the invention, the anchoring depth is more than 50%, in particular at least 70%, and preferably at least 90% of the thickness of the structural element at the hole in which the respective fastening element is attached, perpendicular to the surface of the structural element to which the tab is attached.

[0014] It is also possible to specify the anchorage depth of the fasteners so that the fasteners reach to or close to an opposite surface of the structural element that is opposite the surface of the structural element to which the fishplate is attached. "Close" in this respect can mean to within one or a few millimeters, to about one centimeter, or to a maximum of three centimeters. The latter is a measure to prevent rusting of the fasteners in concrete if they are made of, for example, structural steel or another rusting metal. A smaller distance of one end of the fasteners from the opposite surface of the structural element is possible if rusting is accepted or excluded. However, the structural element should be thick enough for the fasteners to penetrate the structural element by more than 50%.

[0015] Preferably, all or at least a majority of the fastening elements have these

[0016] Anchoring depth in the structural element, wherein at least two fastening elements having this anchoring depth are sufficient for embodiments of the invention.

[0017] The relatively large anchoring depth of the fastening elements in the structural element according to the invention has the advantage that the fastening elements act as internal reinforcement in the structural element, similar to reinforcement. For example, in a structural element made of reinforced concrete, the shear strength and thus the load-bearing capacity of the structural element as a whole are increased compared to a system with a smaller anchoring depth.

[0018] The fastening elements of the system according to the invention have a dual function: they fasten the tab to the surface of the structural element (“external function” or “external reinforcement”) and they increase the strength of the structural element with respect to shear forces acting within the structural element, for example obliquely to the longitudinal axis of the fastening element (“internal function” or “internal reinforcement”).

[0019] In addition to its attachment with the fasteners, the tab may be attached to the structural element in another way, for example by means of a bonding agent in a material bond with the surface of the structural element, as described above.

[0020] The dependent claims relate to advantageous embodiments and further developments of the invention defined in claim 1.

[0021] The holes in the structural element in which the fastening elements are anchored may pass through the structural element, but they are preferably not continuous blind holes such that the holes are closed on a side opposite the tab and the fastening elements are covered by the structural element at a base of the blind holes.

[0022] Examples of structural elements reinforced according to the invention are a building ceiling, a floor slab, a wall or a beam, for example of a building ceiling.

[0023] One embodiment of the invention provides for fastening the tab to the surface of the structural element with at least three fastening elements, which are distributed in a first, a second, and a third third of the tab, wherein the thirds refer to the length of the tab. In other words, the fastening elements are preferably distributed not only at the ends, but also in the middle or over the entire length of the tab. The fastening elements can be distributed evenly or unevenly along the length of the tab, and / or the system according to the invention can comprise additional fastening elements.

[0024] Preferably, the fastening elements do not pass through the structural element, but have an anchoring depth of a maximum of 95% and in particular a maximum of 90% of the thickness of the structural element perpendicular to the surface to which the tab is attached. This embodiment of the invention does not exclude through holes in which the fastening elements are anchored. However, this embodiment of the invention preferably has blind holes in which the fastening elements are attached. Preferably, all or at least a majority of the fastening elements have an anchoring depth of a maximum of 95% or a maximum of 90% of the thickness of the structural element; however, according to the invention, it is sufficient if at least two of the fastening elements have this anchoring depth.

[0025] In preferred embodiments of the invention, the tab consists of a structural steel, for example in accordance with DIN EN 10025 in the 2019 version. However, a tab made of a stainless steel, of another rusting or non-rusting metal or of a non-metallic material such as a fiber-reinforced plastic is also possible.

[0026] The fasteners within the structural element can be threadless or threaded, whereby the thread can be screwed into the hole or not, but simply anchored with the bonding agent. For example, the fasteners are threaded rods. These have a machine thread. Outside the structural element, the fasteners can, for example, have a head or also a thread. A continuous thread along the length of the fasteners is possible, or the fasteners outside the structural element can have a different thread than the one inside the structural element.

[0027] Preferably, the outer diameter of the fasteners is smaller than the hole diameter, and the fastener is anchored in the hole with a cured binder, essentially along the entire length of the hole. The "outer diameter" refers to the diameter of an imaginary cylinder surrounding the fastener in the area of ​​the holes. The "hole diameter" refers to the diameter of an imaginary cylinder inscribed in the drilled hole.

[0028] In other words, the fastener has play in the hole.

[0029] Regardless of the type of fastening element, but particularly in the case of threaded rods as fastening elements, one embodiment of the invention provides for a gap between a thread of the fastening elements or the threaded rods and a hole wall of the holes in the structural element. Preferably, the fastening elements or the threaded rods are arranged coaxially in the holes such that the gap completely encloses the fastening elements or the threaded rods in the holes. Even if the fastening elements or the threaded rods are not coaxial in the holes, the gap can completely enclose the fastening elements or the threaded rods, in which case a thickness of the gap changes over a circumference and / or a length of the fastening elements.By parallel offsetting or arranging the fasteners at an angle in the holes of the structural element, the thread of the threaded rod can partially contact the hole wall without cutting into it. Preferably, the gap is completely or possibly only partially filled with the bonding agent.

[0030] In particular, it is also possible according to the invention for a thread of the fastening element to rest against the hole wall substantially over its entire circumference and / or substantially over its entire length without cutting into it, and for the remaining space, in particular between the thread flanks, to be filled with the binding agent.

[0031] The tab preferably has a through-hole through which one of the fastening elements protrudes. In particular, each of the fastening elements protrudes through a through-hole. A hardened mass, in particular the binding agent with which the fastening element is fastened in the hole, is preferably arranged in an annular gap between the fastening element and the wall of the through-hole. In particular, the annular gap is essentially completely filled with the hardened mass. This ensures that forces acting perpendicular to the longitudinal axis of the fastening element are transmitted by the hardened mass, i.e. there is no play between the fastening element and the tab. One embodiment of the invention provides fastening elements that are welded to the tab or welded to the tab. In this case, too, this preferably applies to all or at least a majority of the fastening elements.However, embodiments of the invention are also possible in which at least two fastening elements are welded to the tab or welded to the tab.

[0032] Reinforcing bars, also known as reinforcement bars, can also be used as fastening elements. Reinforcing bars typically have ribs or beads that extend obliquely to a radial plane of the reinforcing bars and are usually limited to less than 180° in a circumferential direction of the reinforcing bars.

[0033] The features and combinations of features, embodiments and configurations of the invention mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or drawn in a figure can be used not only in the respective combination specified or drawn, but also in principle any other combinations or individually. Embodiments of the invention are possible which do not have all the features of a dependent claim. Individual features of a claim can also be replaced by other disclosed features or combinations of features. Embodiments of the invention which do not have all the features of the exemplary embodiment, but basically any part of the identified features of the exemplary embodiment, are possible.

[0034] The invention is explained in more detail below using an exemplary embodiment illustrated in the drawing. In the drawings:

[0035] Figure 1 shows a longitudinal section of a system for reinforcing a structural element of a building according to the invention; and

[0036] Figure 2 shows an enlarged cross-section of the system from Figure 1.

[0037] The system 1 shown in the figures serves to reinforce a structural element 2 of a structure (not otherwise shown) that could otherwise be any structure, such as a building or a bridge. A structural element of a structure is a construction that provides mechanical stability to the structure and can be part of the structure. The structure as a whole can also form the structural element or have a structural element. Structural element 2 is an element of the structural element, for example, a ceiling or a beam.

[0038] As an example of a structural element 2 for explaining the invention, a ceiling 3 of a building, not otherwise shown, has been chosen here, the building forming the structure.

[0039] The ceiling 3 is arranged horizontally and, in the exemplary embodiment, consists of reinforced concrete, i.e. of a concrete which has a steel reinforcement, for example of a structural steel, for example in accordance with the standard EN10025 in the version of 2019.

[0040] According to the invention, a tab 5 is arranged in a flat manner on a lower surface 4 of the supporting structure element 2, whereby “flat manner” means that the tab 5 rests against the surface 4 of the supporting structure element 2 with one of its two large sides extending in a longitudinal direction and in a transverse direction of the tab 5. The tab 5 can rest against the surface 4 of the supporting structure element 2 with its entire surface, or there can be places or regions in which the tab 5 does not rest against the surface 4 of the supporting structure element 2, but rather there is a gap between the tab 5 and the supporting structure element 2.

[0041] The tab 5 is strip-shaped and, in the exemplary embodiment, is made of steel, for example, of structural steel in accordance with the EN 10025 standard in the 2019 version. Other metallic or non-metallic materials are possible; for example, the tab 5 can be made of stainless steel or a fiber-reinforced plastic.

[0042] In the exemplary embodiment, the tab 5 has a width B of 200 mm, but can also be up to 10% or up to 50% narrower or wider, for example. The width B extends perpendicular to the plane of the figure. A thickness D of the tab 5 is between 5 and 15 mm; in the exemplary embodiment, the tab 5 is 10 mm thick. A length L of the tab 5 depends on structural conditions, in particular on the dimensions of the supporting structure element 2. The tab 5 is in particular at least twice as long as it is wide, and preferably at least 5 to 10 times as long as it is wide.

[0043] In the exemplary embodiment, the tab 5 is fastened in or on a tensile zone of the structural element 2, i.e., on a surface 4 of the structural element 2 that is subjected to tensile stress when the structural element 2 is loaded. In the exemplary embodiment, the tab 5 is thus fastened to an underside of the horizontally arranged ceiling 3 forming the structural element 2.

[0044] The tab 5 is attached to the surface 4 of the structural element 2 with fastening elements 6. The fastening elements 6 are, in particular, rod-shaped; in the exemplary embodiment, threaded rods 7 are used as fastening elements 6, which are inserted through through holes 10 in the tab 5 into holes 8 in the structural element 2. Reinforcing bars, for example, can also be used as fastening elements 6 (not shown). The hole diameters of the holes 8 are larger than the outer diameters of the fastening elements 6.

[0045] The fastening elements 6, or threaded rods 7, and the holes 8 are perpendicular to the surface 4 of the supporting structure element 2 to which the bracket 5 is attached. An inclination of the fastening elements 6 of up to 40° relative to the surface 4 is also possible.

[0046] According to the invention, an anchoring depth Ti of the fastening elements 6 is at least 50% of a thickness of the structural element 2, wherein the thickness is a distance between the surface 4 of the structural element 2, to which the tab 5 is fastened, and an opposite surface 9 of the structural element 2 at the location where the fastening element 6 is arranged. In the exemplary embodiment in which the structural element 2 is the horizontal ceiling 3, the thickness is a distance between a top side and the bottom side of the ceiling 3.

[0047] The anchoring depth Ti is the extension of the respective fastening elements 6 within the structural element 2 perpendicular to the surface 4 of the structural element 2 against which the tab 5 rests. In the exemplary embodiment, the anchoring depth Ti is 90% of the thickness of the structural element 2; the figures are not to scale.

[0048] According to the invention, the fastening elements 6 could pass through the supporting structure element 2 and even protrude from the supporting structure element 2 at the surface 9 opposite the tab 5. In the exemplary embodiment, however, the fastening elements 6 end below the opposite surface 9 within the supporting structure element 2.

[0049] According to the invention, the holes 8 in the supporting structure element 2, in which the fastening elements 6 are attached, could be through holes. In the exemplary embodiment, the holes 8 are cylindrical blind holes, created, for example, by drilling. On the surface 9 opposite the tab 5, the supporting structure element 2 thus covers the fastening elements 6.

[0050] The fastening elements 6 are fastened in the holes 8 in the supporting structure element 2 using a mortar as a binding agent, although other hardening binding agents such as adhesives or synthetic resins can also be used to fasten the fastening elements 6 in the holes 8 of the supporting structure element 2.

[0051] The fastening elements 6 are arranged concentrically or at least in the holes 8 in the structural element 2 in such a way that they do not touch any of the hole walls of the holes 8. The fastening elements 6 are completely enclosed in the holes by the mortar or, in general, the binding agent.

[0052] The binding agent extends into an annular gap 11 formed between the threaded rod 7 and the wall of the through-hole 10 in the link plate 5. As a result, forces acting in the longitudinal direction of the link plate 5 can be transmitted to the threaded rod 7 via the binding agent in the annular gap 11. Such forces can also be transmitted without the binding agent in the annular gap 11, but to a lesser extent or only after a displacement, namely when the wall of the through-hole 10 rests against the threaded rod 7. By means of a nut 12 screwed onto the threaded rod 7 and a washer 13, the link plate 5 is clamped against the surface 4 of the structural element 2. Without the binding agent in the annular gap, forces along the link plate 5 can also be transmitted to the threaded rod 7 due to a frictional engagement acting between the link plate 5, the washer 13 and the nut 12, albeit to a lesser extent.

[0053] Due to their fastening in the holes 8 in the structural element 2 and the large anchoring depth Ti, the fastening elements 6 have a dual function: On the one hand, the fastening elements 6 fasten the tab 5 to the structural element 2 and, on the other hand, the fastening elements 6 reinforce the structural element 2 in a similar way to the reinforcement inside.

[0054] The fastening elements 6 are arranged evenly or unevenly distributed over the length L of the tab 5, with at least one fastening element 6 being arranged in each third of the tab 5 in the longitudinal direction of the tab 5. In addition to the fastening with the fastening elements 6, the tab 5 can be fastened to the structural element 2 in another way, for example, by means of a material bond, for example by gluing.

[0055] Embodiments of the invention are also possible in which the fastening elements 6 are welded to the tab 5 or welded to the tab 5.

[0056] FIW2927.1 02.10.2024

[0057] USU

[0058] List of reference symbols

[0059] System for strengthening a structural element of a building

[0060] Tj anchorage depth

[0061] B Width

[0062] D Thickness

[0063] L length

[0064] 1 system

[0065] 2 structural element

[0066] 3 blanket

[0067] 4 Surface

[0068] 5 tab

[0069] 6 Fastening element

[0070] 7 threaded rod

[0071] 8 holes

[0072] 9 opposite surface

[0073] 10 through hole

[0074] 11 Annular gap

Claims

Claims 1. System (1) for reinforcing a structural element (2) of a building, in particular made of reinforced concrete, with a tab (5), in particular made of steel, which is fastened to the structural element (2) by means of fastening elements (6) and bears flat against a surface (4) of the structural element (2), wherein the fastening elements (6) are each anchored in a hole (8) with an anchoring depth (Ti), in particular fastened with a hardened binder, characterized in that the anchoring depth (Ti) of at least two fastening elements (6), preferably a plurality of the fastening elements (6) and in particular all fastening elements (6) is more than 50%, in particular at least 70% and preferably at least 90%, of a thickness of the structural element (2), measured perpendicular to the surface (4) of the structural element (2) against which the tab (5) bears, in the region of the hole (8).

2. System (1) according to claim 1, characterized in that the holes (8) in the supporting structure element (2) in which the fastening elements (6) are anchored are blind holes.

3. System (1) according to claim 1 or 2, characterized in that the supporting structure element is a ceiling (3), a floor slab, a wall or a beam.

4. System (1) according to one or more of claims 1 to 3, characterized in that at least one fastening element (6) is arranged in a first, a second and a third third of the tab (5), wherein the thirds are related to a length of the tab (5).

5. System (1 ) according to one or more of the preceding claims, characterized in that the anchoring depth (Ti) of at least two Fastening elements (6), preferably a plurality of the fastening elements (6) and in particular all fastening elements (6), is a maximum of 95%, in particular a maximum of 90% of the thickness of the supporting structure element (2), measured perpendicular to the surface (4) of the supporting structure element (2) against which the tab (5) rests, in the region of the hole (8).

6. System (1) according to one or more of the preceding claims, characterized in that the tab (5) is made of structural steel.

7. System (1) according to one or more of the preceding claims, characterized in that the fastening elements (6) are threaded rods (7).

8. System (1) according to one or more of the preceding claims, characterized in that fastening elements (6) are each substantially completely spaced from a hole wall of the hole (8) with an intermediate space and the intermediate space is substantially completely filled with the binding agent.

9. System (1) according to one or more of the preceding claims, characterized in that the tab (5) has a through-hole (10) through which one of the fastening elements (6) projects and in that a hardened mass, in particular the binding agent, is arranged in an annular gap (11) between the fastening element (6) and the wall of the through-hole (10).

10. System (1) according to one or more of the preceding claims, characterized in that at least two, in particular all, fastening elements (6) are welded to the tab (5).

11. System (1) according to one or more of the preceding claims, characterized in that the fastening elements (6) are reinforcing bars.

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