Strip-shaped connection element for a steel-concrete connection

Abstract

A connection element formed of a strip of a corrugated sheet and including a plurality of bearing surfaces (3) spaced from each other and located in a common plane; at least one attachment opening (6, 7) formed in at least one bearing surface (3); a plurality of free-lying top surfaces (4) extending parallel to the bearing surfaces (3); free-lying legs (5) extending between respective bearing surfaces (3) and the top surfaces (4); and at least one through-opening (10, 11, 12, 13, 14, 15, 16, 17) formed in at least one of free-lying top surfaces and legs.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a strip-shaped connection element for a steel-concrete connection and including a plurality of bearing surfaces spaced from each other and located in a common plane, at least one attachment opening formed in at least one bearing surface, a plurality of free-lying top surfaces extending parallel to the bearing surfaces and free-lying legs extending between respective bearing surfaces and the top surfaces.

[0003] 2. Background of the Invention

[0004] Composite floors are formed of different materials and may have a different carrying capacity. By combining different materials not only their different advantages can be combined but also an optimal use of their properties can be achieved. International Publication WO 89/00223 discloses, e.g., a composite floor formed of steel beams, sheets having trapezoidal corrugations, connection elements and concrete. The connection elements, which are formed of strips of sheets with trapezoidal corrugations are designed for receiving lateral loads acting on the floor when substantially vertical forces are applied to the floor from outside. The connection elements are only then able to withstand these lateral forces when the concrete completely surrounds the connection elements and a good bonding is formed between the connection elements and the concrete.

[0005] A connection element, which is disclosed in WO 89/00223 has large-surface tops, which extend parallel to its bearing surfaces, and large-surface legs extending at an angle to the tops and the bearing surfaces. When concrete is poured on the floor, which is formed of sheets having trapezoidal corrugations, it may happen that the concrete would not completely surround the connection elements. This can take place when the concrete is poured on the floor in a somewhat “dry” condition. In this case, an adequate bonding between a connection element and the concrete cannot be obtained. In addition, the “dry” concrete adversely affects the carrying capacity of the composite floor. “Dry” concrete is a concrete that, upon being pumped onto a floor or poured thereon, is actually moist but can flow very slowly.

[0006] Accordingly, an object of the present invention is to provide a connection element that can reliably withstand lateral forces acting on a composite floor as a result of application to the floor forces acting substantially perpendicular to the floor.

[0007] Another object of the present invention is to provide a connection element which would insure a reliable bonding even with a “dry” concrete.

SUMMARY OF THE INVENTION

[0008] These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing, in at least one free-lying surface of the connection element-forming strip, at least one through-opening.

[0009] When the concrete is poured onto a floor, which is formed of a plurality of sheets with trapezoidal corrugations, the concrete would completely surround at least one of the free-lying surfaces of the connection element by filling the through-opening. In this way, a reliable static friction between the concrete and the connection element-forming strip is achieved, while the formation of air pockets is prevented.

[0010] Upon the use of connection elements in floors with a very high height of the concrete, the connection elements are formed of sheets with corrugations the leg surfaces of which are noticeably larger than the top surfaces. In order for the concrete to be able to reach under the top surfaces and behind the leg surfaces, preferably, the free-lying surfaces are formed by the leg surfaces.

[0011] Another case is when the composite floor is very thin and the height of the concrete is very small. In this case, connection elements are used the top surfaces of which are noticeably larger than the leg surfaces, and the openings are formed in the top surfaces. The advantage of formation of through-openings in the top surfaces consists in that upon pouring of the concrete on the floor, which is formed of sheets with trapezoidal corrugations, the formation of air pockets, which adversely affect bonding between the concrete and the connection element is reliably prevented.

[0012] In order to prevent formation of the air pockets in the region of a connection element when the concrete is poured onto the floor, preferably, the through-openings are formed in both the leg surfaces and the top surfaces. Another advantage of forming of the through-openings in both the top and leg surfaces consists in that the height of the connection element, if needed, can be made very small. This is because the concrete can flow inside of the connection element through the opening in the top surface and need not be flown under the connection element from the side.

[0013] In order to be able to attain a sufficiently high tensile strength of the connection element, advantageously, the entire cross-section of the through-openings formed in the leg surfaces amounts at most to 75% of the entire surface of the legs.

[0014] In order to prevent the tensile forces, which act on the connection element, from exceeding a predetermined threshold on one of both longitudinal sides, advantageously, a width of a web between the outer surface of the connection element-forming strip and an inner wall of the opening and which is measured in a direction parallel to the bearing surfaces and perpendicular to the longitudinal extent of the connection element, corresponds at least to 0.05-0.3 times of an entire width of the connection element-forming strip.

[0015] The through-openings can have a circular cross-section or a cross-section which deviates from a circle. This means that the through-openings can have, e.g., a square, rectangular, oval, elliptical, etc . . . cross-section. The rectangular through-openings can, e.g., be formed as slots extending from the bearing surface along the entire length of the leg and up to the top surface. It is possible to provide in a leg one or more slots extending at an angle to the length of the leg surface. In order to prevent stress concentration in the comers of the through-openings, the comers are rounded.

[0016] The shape and the size of the cross-section of the openings and the number of the openings depends in a large degree on the mix of the concrete and the moisture of the concrete poured onto the floor, which is formed of sheets with trapezoidal corrugations. In order to be able to use a very “dry” concrete for covering the floor and including relatively large pebbles, connection elements are used which have a large opening in the leg surface and/or in the top surface. Concrete can rather easily penetrate through such “large” opening.

[0017] When concrete with small-size pebbles and having a high moisture content is used, the connection elements with through-openings having a small cross-section, can be used.

[0018] In order for a connection-element to be able to withstand lateral forces acting in the floor, advantageously, the angle between the bearing surface of the connection element and the leg surface amounts from about 60° to 90°. With an angle of 90°, it is the bearing and top surfaces that receive the tensile stresses acting on the connection element. When the leg surfaces extend to the top and bearing surfaces at an angle of 60°, the leg surfaces contributes to receiving the tensile forces, together with the top and bearing surfaces. When, e.g., the forces constantly act on the floor at an angle, it is possible to so form the connection element that two adjacent leg surfaces extend at different angles to the bearing and/or top surface.

[0019] The wall thickness of the sheet, of which the connection element is formed, depends primarily on the vertical forces acting on the floor, which are transmitted to the floor by the connection elements. Advantageously, the wall thickness amounts from 0.75 mm to 3 mm.

[0020] In order to be able to prevent contamination of the connection elements before pouring of concrete on the floor formed of sheets with trapezoidal corrugations to the most possible extent, preferably, the connection elements are formed with smooth surfaces. The dirt, because of the smooth surfaces of the connection elements, cannot adhere to them. It is, however, also possible to provide the connection element surfaces with an appropriate profile when a particularly good bonding between the connection elements and the concrete should be obtained.

[0021] The corrosion of a connection element can be prevented by covering the sheet with zinc layer.

[0022] The width of the connection element-forming strip can be selected from 30 mm to 300 mm.

[0023] The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Single Figure of the drawings shows a perspective, view of a connection element according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0025] The drawing shows an I-beam 2 which supports a portion of a floor 9 formed of a plurality of sheets having trapezoidal corrugations. In the drawing, only one sheet is shown. On a side of the floor 9 remote from the I-beam 2, precisely above the I-beam 2, there is provided a connection element according to the present invention formed of a strip 1 of a sheet with trapezoidal corrugations. As shown in the drawing, the legs 5 of the connection element are longer than the legs of the corrugated sheet the floor portion is made of. As a result, the top of the connection element is spaced from the top of the floor-forming corrugated sheet. The length L1 of the bearing surfaces 3 of the connection element, measured along the longitudinal extent of the connection element, is shorter than the length L2 of the top surfaces 4 of the connection element and shorter than the bearing surfaces of the corrugations of the sheet the floor is made of. The top surfaces 4 of the connection element can be longer than both the bearing surfaces 3 of the connection element and the bearing surfaces of the floor sheet. This is particular the case when, e.g., the bearing surfaces of the connection element cooperate only with every other bearing surface of the floor sheet.

[0026] For securing the floor sheet and the connection element to the I-beam 2, e.g., nail-shaped fasteners 6, 7 can be used. The fasteners 6, 7 penetrate through the bearing surfaces 3 of the connection element-forming strip 1 and the bearing surfaces of the floor-forming sheet and are driven into the I-beam 2. For driving-in of the nail-shaped fasteners through the bearing surfaces of the connection element and the floor and into the I-beam 2, gas, pressure, or explosive powder-actuated setting tools can be used. However, the connection element can be connected with the floor 9 by welding or with screws.

[0027] The legs 5 of the connection element extend to its bearing surfaces 3 and top surfaces 4 at an angle W from 60° to 90°. Through-openings 10, 11, 12, 13, 14, 15, 16, and 17 are provided in the legs 5 and top surfaces 4. The through-openings 10-17 differ from each other in their cross-section and size. The through-openings 10-17 can have, e.g., circular, square, rectangular, oval, elliptical, etc . . . cross-section. In each of the legs 5 or the top surfaces 4, instead of one through-opening 10, 11, 12, 13, 14, 15, 16, 17, two or more such openings can be provided.

[0028] In a single connection element, the through-openings 10-17 can have the same cross-section and the same size, the same cross-sectional shape but different sizes, different cross-sectional shapes and sizes, different cross-sectional shapes and the same size. The strip 1 has a width B1 which can amount from 30 mm to 300 mm.

[0029] The width of the web B2, which is defined by an outer surface 18 of the strip I and the inner wall of the opening 10, 11, 12, 13, 14, 15 and is measured in a direction parallel to the bearing surface 3 and perpendicular to the longitudinal extent of the sheet 1, corresponds at least to 0.05÷0.3 of the width B1 of the strip 1.

[0030] The floor 9 and the connection element are covered with concrete 8 which penetrates through the through-openings 10, 11, 12, 13, 14, 15, 16, and 17. The concrete 8 covers the floor 9 and the connection element from all sides.

[0031] Though the present invention was shown and described with references to the preferred embodiment, such are merely illustrative of the present invention and are not to be construed as a limitation thereof, and various modifications of the present invention will be apparent to those skilled in the art. It is, therefore, not intended that the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A connection element formed of a strip of a corrugated sheet, comprising a plurality of bearing surfaces (3) spaced from each other and located in a common plane; at least one attachment opening (6, 7) formed in at least one bearing surface (3); a plurality of free-lying top surfaces (4) extending parallel to the bearing surfaces (3); free-lying legs (5) extending between respective bearing surfaces (3) and the top surfaces (4); and at least one through-opening (10, 11, 12, 13, 14, 15, 16, 17) formed in at least one of free-lying top surfaces and legs.

2. A connection element according to

claim 1, wherein at least one through-opening (10, 11, 12, 13, 14, 15, 16, 17) is formed in each of several free-lying top surfaces and legs.

3. A connection element according to

claim 2, wherein at least one through-opening (10, 11, 12, 13, 14, 15, 16, 17) is formed in each of the free-lying top surfaces (4) and legs (5).

4. A connection element according to

claim 3, wherein an entire cross-section of through-openings (10, 11, 12, 13, 14, 15) formed in the legs (5) at most amounts to 75% of an entire surface of the legs (5).

5. A connection element according to

claim 1, wherein a width (B2) of a web defined by an outer surface (18) of the connection element-forming strip (1) and an inner wall of the at least one opening (10, 11, 12, 13, 14, 15) and is measured in a direction parallel to the bearing surface 3 and perpendicular to a longitudinal extent of the strip (1) corresponds at least to 0.05÷0.3 of a width (B1) of the strip (1).

6. A connection element according to

claim 1, wherein the connection element-forming strip (1) has a thickness which amounts from 0.75 mm to 3 mm.

7. A connection element according to

claim 1, wherein the connection element-forming strip (1) has a smooth outer surface.