EP0495334B1 - Bent up bars for flat slab floors - Google Patents

Abstract

These bent-up bars are intended for flat slab floors mounted on supports and consisting of reinforced or prestressed concrete. They are provided, to increase the loadbearing capacity of zones subjected to transverse force in the region of these zones and corresponding to the requirements for shear allowance, with groups (a, b) of reinforcing bars (5) running at least approximately perpendicularly to the floor surface (4) and extending inside the flat slab floor (2). To achieve simple laying, said reinforcing bars are each provided at their upper and lower ends with a thickened head (6, 7) and are firmly connected to one another at their upper ends (6), in groups, by means of one spacer (8) in each case. In this case, the spacer (8) intended for resting on the upper bending reinforcement (9) is bent or angled at least over part of its length, seen in a horizontal plane. <IMAGE>

Description

The invention relates to reinforcement consisting of at least one upper horizontal bending reinforcement and shear reinforcement elements for flat slabs made of reinforced or prestressed concrete supported on supports, which, in order to increase the load-bearing capacity of zones subjected to shear forces, in particular zones prone to punching, in the area of these zones meet the requirements of shear coverage with groups of at least approximately perpendicular shear reinforcing bars extending to the ceiling surface and extending inside the flat slab are provided, the latter being provided with a thickening head at their upper and lower ends, and are firmly connected to one another in groups to form the shear reinforcement elements by means of a spacer, a shear reinforcement element for one such shear reinforcement and a method of making such reinforcement.

From DE-A-3 331 275 shear reinforcement elements designed as double-headed bolts are known which can be laterally connected to one another in a manner not specified. From DE-A-35 23 656 a shear reinforcement system serving as punching shear reinforcement is also known, which consists of edged lattice-like, ladder-like or truss-like, essentially V-shaped individual elements.

However, these known shear reinforcements all have the disadvantage that they are designed before the lower bending reinforcement is laid and to avoid this a subsequent overturning when concreting must be nailed to the lower formwork, which is extremely cumbersome firstly, and secondly, in the event of an oversight, no subsequent arrangement is permitted.

The object of the present invention is, in particular, to create a shear reinforcement which, after arranging the lower and upper bending reinforcement nets, can be laid in a simple manner from above, which enables reinforcement bars which are connected to one another and run perpendicular to the ceiling surface to be reinforced, and at the same time tilt the latter prevented when concreting in a very simple manner.

This object is achieved in a shear reinforcement of the type mentioned in the invention according to the characterizing part of claim 1.

Advantageous further developments of the invention are the subject of claims 2 to 10.

The present invention further relates to a shear reinforcement element according to claim 11 and a method for producing a reinforcement according to claim 1.

• Fig. 1 einen Vertikalschnitt durch eine erste beispielsweise Ausführungsform einer erfindungsgemässen Schubbewehrung;
• Fig. 2 eine Draufsicht auf die in Figur 1 dargestellte Schubbewehrung, wobei zur besseren Übersicht nur zwei über Abstandhalter verbundene Bewehrungsstabgruppen eingezeichnet sind;
• Fig. 3 eine Draufsicht analog Figur 2 auf eine zweite beispielsweise Form des Abstandhalters;
• Fig. 4 eine Draufsicht analog Figur 2 auf eine dritte beispielsweise Form des Abstandhalters;
• Fig. 5 eine Draufsicht analog Figur 2 auf eine vierte beispielsweise Form des Abstandhalters;
• Fig. 6 einen Schnitt längs der Linie VI-VI in Figur 5;
• Fig. 7 einen Schnitt analog Figur 6 durch eine fünfte beispielsweise Ausführungsform des Abstandhalters; und
• Fig. 8 einen Schnitt analog Figur 6 durch eine weitere beispielsweise Ausführungsform einer Schubbewehrung.

The invention is explained below with reference to the drawing, for example. It shows:

• 1 shows a vertical section through a first exemplary embodiment of a shear reinforcement according to the invention;
• Fig. 2 is a plan view of the shear reinforcement shown in Figure 1, with a better overview only two reinforcement bar groups connected via spacers are shown;
• 3 shows a top view analogous to FIG. 2 of a second, for example, shape of the spacer;
• 4 shows a top view analogous to FIG. 2 of a third, for example, shape of the spacer;
• 5 shows a top view analogous to FIG. 2 of a fourth, for example, shape of the spacer;
• 6 shows a section along the line VI-VI in FIG. 5;
• 7 shows a section analogous to FIG. 6 through a fifth exemplary embodiment of the spacer; and
• 8 shows a section analogous to FIG. 6 through a further exemplary embodiment of a shear reinforcement.

In the case of the locally used shear reinforcement elements 3 shown in FIGS. 1 and 2, which are used for flat ceilings 2 supported on supports 1 and made of reinforced or prestressed concrete, zones to increase the load-bearing capacity of zones subjected to shear forces, in particular zones prone to punching, meet the requirements of shear coverage Correspondingly arranged groups a, b of shear reinforcement bars 5 running perpendicular to the ceiling surface 4 and extending inside the flat ceiling 2 are provided. The latter are preferably made of corrugated structural steel and are provided at their upper and lower ends with a conical or truncated pyramid-shaped head 6 and 7, respectively.

For the sake of simplicity and for a better overview, only two instead of a plurality of locally applicable shear reinforcement elements 5, 8 are shown in FIGS. 1 and 2.

For the simplest possible assembly of individual shear reinforcement bar groups a, b and for lateral support thereof to avoid uncontrolled swiveling out of the shear reinforcement bars 5 during concreting, the latter are firmly connected to one another at their upper ends by a spacer 8 also made of corrugated structural steel, the to rest on the upper bending reinforcement 9 of the flat ceiling 2 certain spacers 8 for its lateral support, ie To avoid any uncontrolled and undesired rotation about its longitudinal axis 10 when concreting, as can be seen clearly in FIG. 2, viewed in a horizontal plane, is provided with end sections 11 and 12 which are angled by 90 °.

In general, it is advantageous, after inserting the individual shear reinforcement elements 5, 8 from above into the upper bending reinforcement 9, to additionally lock the angled end sections 11 and 12 by means of a wire loop 13 and / or 14, each with a lattice bar running below, to lock their position To connect bending reinforcement 9, so that their position remains unchanged when concreting.

In the following, parts that are analogous to parts shown in FIGS. 1 and 2 are provided with the same reference symbols, so that a repeated description of these parts is unnecessary.

As can be seen from FIGS. 3 and 4, the spacer 8, which is firmly welded to a group of spaced-apart shear reinforcing bars 5, can also be angled in a V-shape (FIG. 3) or wavy (FIG. 4) in a horizontal plane, as a result of which, when supported on the upper bending reinforcement 9 a very good positional stability of the shear reinforcement bars 5 extending vertically downwards can be achieved in a simple manner when concreting the flat slab 2.

In the embodiments shown in FIGS. 5, 6 and 7, the spacers 8 consist of two rod-shaped spacer elements 8 ′ and 8 ″, which are arranged next to one another but slightly spaced apart from one another laterally, the ends 11 ′, 11 ″ and 12 ′ respectively adjacent to one another , 12 '' of the latter, viewed in a horizontal plane (FIG. 5), are bent away from one another by 90 °, so that this also provides good support for the position of the shear reinforcing bars 5 which extend vertically down to the region of the lower bending reinforcement 15 when concreting the flat ceiling 2 is reached.

As can be seen from FIG. 7, it is also possible for the ends 16 and 17 of the bent parts 11 ′ and 11 ″ of the two rod-shaped spacer elements 8 ′ and 8 ″ to be bent downwards in such a way that they are bent downwards End parts 16 and 17, when engaged with the upper reticular reinforcement 9, center the relevant spacer 8 and thus the group of vertically downwardly extending shear reinforcement bars 5 firmly connected to the latter in the meshes of the upper bending reinforcement 9.

As can also be seen from FIG. 8, it is also possible for at least some of the downward ends of the shear reinforcement bars 5 to be provided with spacers 18 that can be embedded in concrete for resting on the lower formwork when concreting the flat slab 2, and then above the upper bending reinforcement 9 spacers 8 are fixed by means of a wire loop 19 to the upper bending reinforcement 9, so that the shear reinforcement bars 5 are not undesirably moved from their predetermined position when concreting the flat slab 2.

Claims (12)

1. Reinforcement made of at least one upper horizontal bending reinforcement (9) and bent-up bar elements for flat ceilings made of reinforce concrete or prestressed concrete supported on columns, which are intended to increase the load-bearing capacity of zones with transverse loads, especially of zones endangered by breaching, whereby, to meet the requirements of the thrust, these zones have been provided with groups (a, b) of web reinforcement bars (5) at least approximately vertical to the ceiling surface (4) running inside the flat ceiling, whereby these bars have been provided with a thickened head (6, 7) each at their upper and lower end, and which are linked groupwise to one another by means of one bar spacer (8) each to form the web reinforcement elements, and characterised by the fact that the web reinforcement bars (5) are firmly fastened to the bar spacer (8) at their upper end to form the web reinforcement elements, whereby the bar spacer (8) used for the support of the upper bending reinforcement (9) or for protrusion of it is bent or angulated at least for a part of its length, when viewed from the horizontal plane, and characterised by the fact that the individual bar spacers (8) are dimensioned in such a way that, when viewed from a horizontal plane, they protrude from at least two parallel running bars of the upper bending reinforcement (9) for lateral support.
2. Reinforcement as set forth in claim 1 characterised by the fact that the end sections (11, 12) of at least one part of the individual bar spacers (8) are angulated (Fig. 2) by at least 90° preferably, and preferably in opposing directions to be located in one horizontal plane.
3. Reinforcement as set forth in claim 1 characterised by the fact that at least one part of the individual bar spacers (8) is angulated almost in V shape at least, when viewed from a horizontal plane (Fig. 3).
4. Reinforcement as set forth in claim 1 characterised by the fact that at least one part of the individual bar spacers (8) is wave shaped, when viewed from a horizontal plane (Fig. 4).
5. Reinforcement as set forth in one of the claims 1 to 4 characterised by the fact that the thickened heads (6, 7) of the web reinforcement bars (5) firmly fastened to the bar spacers (8) and running vertically to the ceiling surface (4) are shaped almost coniform or like a truncated pyramid at least.
6. Reinforcement as set forth in one of the claims 1 to 5 characterised by the fact that the bar spacers (8) as well as the web reinforcement bars (5) firmly fastened, preferably welded, are made of steel, preferably of constructional steel.
7. Reinforcement as set forth in claim 1 characterised by the fact that the individual bar spacers (8) consist of almost parallel and laterally slightly displaced rod-shaped bar spacer elements (8', 8''), preferably made of constructional steel.
8. Reinforcement as set forth in claim 7 characterised by the fact that, when viewed from a horizontal plane, the respectively neighbouring ends of the two rod-shaped bar spacer elements (8', 8'') are bent away from each other (11', 11''; 12', 12''), preferably by at least 90° each (Figs. 5 to 7).
9. Reinforcement as set forth in claim 8 characterised by the fact that the ends of the bent parts (11', 11''; 12', 12'') of the rod-shaped bar spacer elements (8', 8'') are bent down (16, 17) in such a way that these end parts (16, 17) bent down cause a centring of the bar spacer (8) after contact with the upper web-type bending reinforcement (9), and thus a centring of the latter fastened to the vertical downward running web reinforcement bars (5) in the mesh of the bending reinforcement (9, 15) (Fig. 7).
10. Reinforcement as set forth in claim 1 characterised by the fact that at least one part of the downward pointing ends of the vertically downward running web reinforcement bars (5) have been provided with the bar spacers (18) for rest on the lower shuttering during the concrete placing of the flat ceiling (2), and the bar spacers (8) can be fastened to the upper bending reinforcement (9) by wire (19), for example.
11. Web reinforcement elements with a group of web reinforcement bars fastened to a bar spacer for insertion into a bending reinforcement characterised by the fact that the web reinforcement bars (5) provided with a thickened head (6, 7) on their ends, in the way already described, are firmly fastened to the bar spacer (8) at their upper end, and run in lengthwise direction at least almost vertically to a plane defined by the bar spacer (8), and that the bar spacer (8) has been provided with end sections (11, 12) angulated by at least 90° in a plane vertical to the web reinforcement bars (5).
12. Method for the production of a reinforcement as set forth in claim 1 by means of web reinforcement elements as set forth in claim 11 characterised by the fact that depending on the requirements of the thrust cover a number of web reinforcement elements with their web reinforcement bars (5) pointing downwards are inserted from the top into the upper bending reinforcement of the area of the zones to be reinforced, and that subsequently the bar spacers (8) are firmly fastened to the upper bending reinforcement (9) by wire, for example.

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