Connecting element and assembly for composite concrete construction

Abstract

Connecting element for composite concrete construction with a bolt shaft having a weldable surface, characterized by that the bolt shaft (2) has at least two functionally distinct shaft sections, that one of the shaft sections is designed as an anchor shaft (3) with at least one anchor head (4), that the other shaft section is designed as a threaded shaft (5) with at least one external thread (6), and that the bolt shaft (2) has a ring collar (7) formed between the anchor shaft (3) and the threaded shaft (5), on the side of which facing away from the anchor head (4) the weld surface (1) is formed in a ring shape.

Description

[0001] The invention relates to a connecting element for concrete composite construction with a bolt shank having a welding surface. Furthermore, the invention relates to an assembly for concrete composite construction with an anchor plate having at least one drilled hole and with at least one threaded bolt received in the drilled hole of the anchor plate, which has a bolt shank having a welding surface.

[0002] For connecting steel structures to concrete foundations, the use of so-called anchor plates is common. These are welded studs welded on the underside as headed studs for anchoring in the in-situ concrete, and welded studs welded on the top as threaded studs for screwing to the steel profiles of the steel structure. However, different tolerances apply in steel construction on the one hand and in the shell construction on the other, which regularly necessitate unconventional measures during connection work, which can lead to weakening of the connection. Therefore, anchor plates are often cast in the in-situ concrete without threaded studs, and threaded studs are added as needed.However, subsequent welding of threaded bolts can result in installation positions where the use of welding equipment is difficult and where additional position holders are required for the threaded bolts to be welded. In difficult installation positions, threaded bolts are sometimes even omitted, and the steel profiles of a steel structure are welded to the anchor plates. Such welded joints actually require a weld seam inspection, which is often omitted in practice. Instead, high safety factors are used, which can at least partially call into question the validity of previous static calculations.

[0003] The invention is therefore based on the object of demonstrating a connecting element of the type mentioned at the outset, with which the connection situation between a steel construction and a concrete foundation is improved overall.

[0004] This object is achieved according to the invention by a connecting element having the features of claim 1 and by an assembly having the features of claim 7. Advantageous developments of the invention are specified in the subclaims which refer back to these claims.

[0005] The connecting element according to the invention is characterized in that the bolt shaft has at least two functionally different shaft sections, that one of the shaft sections is designed as an anchor shaft with at least one anchor head, that the other shaft section is designed as a threaded shaft with an external thread, and that the bolt shaft has an annular collar formed between the anchor shaft and the threaded shaft, on the side of which facing away from the anchor head the welding surface is ring-shaped.

[0006] The connecting element according to the invention thus has a dual function, with which a tensile force introduced into the anchor head via the threaded shaft is guided via a homogeneous metal structure and not via two welded joints. A welded joint made between the annular welding surface of the threaded bolt and an anchor plate advantageously serves only to create a composite consisting of several connecting elements and an anchor plate that accommodates the connecting elements. Factory-drilled holes in the anchor plate permits high dimensional accuracy between the drill holes and the positioning of the connecting elements in such drill holes, even in difficult installation positions, without the use of position holders. The connecting element according to the invention thus permits advantageously small tolerances to be maintained for the connection dimensions measured between the threaded shafts.With the connecting element according to the invention, the connection position between a steel structure and a concrete foundation is improved in a particularly efficient manner because tensile forces to be transmitted by the connecting elements do not pass through welded joints and anchor plates provided with drill holes at the factory enable the connecting elements to be held in a precise position without the aid of position holders.

[0007] According to a first refinement of the invention, the welding surface of the stud shank is conically curved. After inserting a fastener into the bore of an anchor plate, the conicity creates a weld groove surrounding the annular collar, where a fillet weld can be performed. However, it is fundamentally within the scope of the invention to design the welding surface as a flat surface and to connect the fastener according to the invention to the anchor plate using the stud welding process.

[0008] According to a further development of the invention, the shaft section formed as a threaded shaft has a greater length than the external thread formed on the threaded shaft. The difference in length preferably corresponds at least to the thickness of an anchor plate, but can also be significantly greater depending on the installation situation.

[0009] According to another embodiment of the invention, the anchor head has a larger diameter than the annular collar. However, other diameter ratios are within the scope of the invention.

[0010] To maximize the load-bearing capacity of the connecting element according to the invention, the anchor head and the annular collar are integrally connected to the bolt shaft. For this purpose, the entire connecting element is preferably manufactured by cold forming.

[0011] In order to be able to serve a maximum range of applications with the connecting element according to the invention, an alternative to the one-piece design of the connecting element is to design the anchor head and the annular collar as individual parts that can be screwed to the bolt shaft. Such individual parts can then be commercially available in a selection of different designs, for example, with different diameters or material thicknesses, so that the connecting element according to the invention can be structurally adapted to different applications and installation situations.

[0012] The assembly according to the invention is characterized in that the bolt shaft has at least two functionally different shaft sections, that one of the shaft sections is designed as an anchor shaft with at least one anchor head, that the other shaft section is designed as a threaded shaft with at least one external thread, and that the bolt shaft has an annular collar formed between the anchor shaft and the threaded shaft, on the side of which facing away from the anchor head the welding surface is annular, that the anchor plate has at least one welding surface delimiting the drill hole, and that the anchor plate and the threaded bolt are welded to one another via their welding surfaces.

[0013] The assembly according to the invention thus has a dual function, with which a tensile force introduced into the anchor head via the threaded shaft is guided via a homogeneous metal structure and not via two welded joints. A welded joint made between the annular welding surface of the threaded bolt and the welding surface of the anchor plate advantageously serves only to create a composite consisting of several connecting elements and an anchor plate receiving the connecting elements. Factory-drilled holes in the anchor plate permits high dimensional accuracy of the drill holes to one another, and positioning of the connecting elements in such drill holes is possible even in difficult installation positions without the use of position holders. The assembly according to the invention thus permits advantageously small tolerances to be maintained for the connection dimensions measured between the threaded shafts.With the assembly according to the invention, the connection position between a steel structure and a concrete foundation is improved in a particularly efficient manner because tensile forces to be transmitted by the connecting elements do not pass through welded joints and anchor plates provided with drill holes at the factory enable the connecting elements to be held in a precise position without the aid of position holders.

[0014] According to a further development of the assembly according to the invention, the anchor plate has a plurality of drill holes, with at least several of the drill holes each accommodating a bolt shaft. Such an anchor plate can advantageously be used universally with different connection dimensions. Drill holes not required for a component connection are simply left free, further improving the integration of the assembly into the in-situ concrete.

[0015] An embodiment of the invention, from which further inventive features emerge, is illustrated in the drawing. They show: Fig. 1: a perspective view of a connecting element according to the invention; and Fig. 2: a perspective view of an assembly according to the invention with a connecting element according to Fig. 1.

[0016] The Fig. 1 shows a perspective view of a connecting element according to the invention for concrete composite construction, comprising a bolt shank 2 having a welding surface 1. This bolt shank has two functionally different shank sections, one of the shank sections being designed as an anchor shank 3 with an anchor head 4, and the other shank section being designed as a threaded shank 5 with an external thread 6. The bolt shank 2 has an annular collar 7 formed between the anchor shank 3 and the threaded shank 5, on the side of which, facing away from the anchor head 4, the welding surface 1 is annular. The anchor head 3 has a larger diameter than the annular collar 7.

[0017] The Fig.Figure 2 shows a perspective view of an assembly according to the invention with an anchor plate 9 having twenty drilled holes 8 and four threaded bolts 10, 11, 12, 13 received in the drilled holes 8. A welded connection 15, 16, 17, 18 is formed between the annular collars 7 of the threaded bolts 10, 11, 12, 13 and the welding surface 14 of the anchor plate 9, which defines the top of the drilled holes 8. Identical structures are provided with the same reference numerals.

Claims

[1] Connecting element for concrete composite construction with a bolt shank having a welding surface, characterized by , that the bolt shaft (2) has at least two functionally different shaft sections, that one of the shaft sections is designed as an anchor shaft (3) with at least one anchor head (4), that the respective other shaft section is designed as a threaded shaft (5) with at least one external thread (6), and that the bolt shaft (2) has an annular collar (7) formed between the anchor shaft (3) and the threaded shaft (5), on the side of which facing away from the anchor head (4) the welding surface (1) is annular. [2] Connecting element according to claim 1, characterized by that the annular welding surface (1) of the bolt shank (2) is conically curved. [3] Connecting element according to claim 1 or 2, characterized bythat the shaft section designed as a threaded shaft (5) has a greater length than the external thread (6) formed on the threaded shaft (5). [4] Connecting element according to one of claims 1 to 3, characterized by that the anchor head (4) has a larger diameter than the ring collar (7). [5] Connecting element according to one of claims 1 to 4, characterized by that the anchor head (4) and the ring collar (7) are integrally connected to the bolt shaft (2). [6] Connecting element according to one of claims 1 to 4, characterized by that the anchor head (4) and the ring collar (7) are designed as individual parts that can be screwed to the bolt shaft (2). [7] Assembly for concrete composite construction with an anchor plate having at least one borehole and with at least one threaded bolt received in the borehole of the anchor plate, which has a bolt shank having a welding surface, characterized by , that the bolt shaft (2) has at least two functionally different shaft sections, that one of the shaft sections is designed as an anchor shaft (3) with at least one anchor head (4), that the respective other shaft section is designed as a threaded shaft (5) with at least one external thread (6), and that the bolt shaft (2) has an annular collar (7) formed between the anchor shaft (3) and the threaded shaft (5), on the side of which facing away from the anchor head (4) the welding surface (1) is annular, that the anchor plate (9) has at least one welding surface (14) delimiting the borehole (8), and that the anchor plate (9) and the threaded bolt (10, 11, 12, 13) are welded together via their welding surfaces (1,14). [8] Assembly according to claim 7, characterized bythat the anchor plate (9) has a plurality of boreholes (8), and that at least a bolt shaft (2) is received in each of at least several of the boreholes (8).

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