CH683545A5 - Shear reinforcement for flat slabs. - 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

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description

The invention relates to shear reinforcement from shear reinforcement elements for flat slabs made of steel or prestressed concrete supported on supports, which, in order to increase the load-bearing capacity of zones subjected to shear forces, in particular zones subject to punching shear in the area of these zones, in accordance with the requirements of shear cover with groups of at least approximately perpendicular to the ceiling surface reinforcing bars extending inside the flat slab is provided, a shear reinforcement element for such shear reinforcement and a method for producing such shear reinforcement.

Shear reinforcements of various types are already known, but they all have the disadvantage that they must either be laid out before the lower bending reinforcement is laid and nailed down to prevent them from tipping over when concreting on the lower formwork, which is extremely cumbersome firstly and secondly Accidental subsequent arrangement is no longer allowed.

The object of the present invention is, in particular, to create a shear reinforcement which, after arranging the lower and upper bending reinforcement meshes, can be laid in a simple manner from above, which enables the laying of reinforcing 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 in a very simple way when concreting.

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 11.

The present invention further relates to a shear reinforcement element according to claim 12 for a shear reinforcement according to claim 1 and a method for producing a shear reinforcement according to claim 1.

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

1 shows a vertical section through a first example embodiment of a shear reinforcement according to the invention;

FIG. 2 shows a plan view of the shear reinforcement shown in FIG. 1, only two reinforcement bar groups connected via spacers being shown for a better overview;

Fig. 3 is a plan view analogous to Figure 2 of a second example of the spacer.

Fig. 4 is a top view analogous to Fig. 2 of a third example of the spacer;

FIG. 5 is a top view analogous to FIG. 2 of a fourth example of the spacer;

Fig. 6 is 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 3 shown in FIGS. 1 and 2, which is 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 Thrust cover correspondingly arranged groups a, b of reinforcing bars 5 extending perpendicular to the ceiling surface 4 and extending in the interior of 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 reinforcement bar groups a, b and for lateral support thereof to avoid uncontrolled swiveling out of the reinforcement bars 5 when concreting, the latter are firmly connected to one another at their upper ends by a spacer 8, also made of corrugated structural steel, by welding, 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 from FIG. 2, viewed in a horizontal plane, is provided with end sections 11 and 12 which are angled by 90 °.

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

Parts that are analogous to parts shown in FIGS. 1 and 2 are subsequently 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 reinforcing bars 5, can also be angled in a V-shape (FIG. 3) or wave-shaped (FIG. 4) in a horizontal plane, as a result of which Support on the upper bending reinforcement 9 in a simple manner a very good positional stability of the reinforcement bars 5 extending vertically downwards can be achieved when concreting the flat slab 2.

In the embodiments shown in FIGS. 5, 6 and 7, the spacers 8 consist

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two rod-shaped spacer elements 8 'and 8 ", which are arranged next to one another but slightly spaced apart from one another, the ends 11', 11" and 12 ', 12 "of the latter being adjacent to each other in a horizontal plane (FIG. 5) as viewed 90 ° apart are bent, so that a good retention of the position of the reinforcing bars 5 extending vertically down to the area of the lower bending reinforcement 15 is also achieved when concreting the flat roof 2.

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 these end parts are bent downwards 16 and 17, when engaged with the upper reticular reinforcement 9, center the spacer 8 in question, and thus the group of vertically downwardly extending reinforcement bars 5, firmly connected to the latter, in the meshes of the upper reinforcement 9.

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

Claims (13)

Claims 1.Shear reinforcement from 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 (a, b) of at least approximately perpendicular to the ceiling surface ( 4) extending, inside the flat ceiling (2) extending reinforcing bars (5) is provided, characterized in that the latter are provided at their upper and lower ends with a thickening head (6, 7) and in groups at their upper ends are firmly connected to each other by means of a spacer (8), the spacer (8) intended to rest on the upper bending reinforcement (9) or projecting above it, viewed in a horizontal plane, being curved or angled over at least part of its length. 2. shear reinforcement according to claim 1, characterized in that the end sections (11, 12) of at least a part of the individual spacers (8), preferably in opposite directions, lying in a horizontal plane, preferably by at least approximately 90 °, are angled ( Fig. 2). 3. shear reinforcement according to claim 1, characterized in that at least a part of the individual spacers (8) viewed in a horizontal plane is angled at least approximately V-shaped (Fig. 3). 4. shear reinforcement according to claim 1, characterized in that at least part of the individual spacers (8) viewed in a horizontal plane is undulating (Fig. 4). 5. shear reinforcement according to one of claims 1 to 4, characterized in that the individual spacers (8) are dimensioned such that, when installed in the bending reinforcement, viewed in a horizontal plane for their lateral support, at least two parallel and parallel bars protrude the upper bending reinforcement (9) (Fig. 2 and 5 to 7). 6. shear reinforcement according to one of claims 1 to 5, characterized in that the thickening heads (6, 7) of the reinforcement bars (5) which are fixedly connected to the spacers (8) and run perpendicular to the ceiling surface (4) are at least approximately conical or are truncated pyramid-shaped. 7. shear reinforcement according to one of claims 1 to 6, characterized in that the spacers (8) and the firmly connected, preferably welded reinforcing bars (5) made of steel, preferably structural steel. 8. shear reinforcement according to claim 1, characterized in that the individual spacers (8) consist of at least two, at least approximately parallel to one another and slightly spaced laterally spaced rod-shaped spacer elements (8 ', 8 "), preferably structural steel. 9. shear reinforcement according to claim 8, characterized in that the mutually adjacent ends of the two rod-shaped spacer elements (8 ', 8 ") as seen in a horizontal plane away from each other, preferably by at least approximately 90 °, bent (11', 11"; 12 ', 12 ") (Figs. 5 to 7). 10. shear reinforcement according to claim 9, characterized in that the ends of the bent parts (11 ', 11 "; 12', 12") of the rod-shaped spacer elements (8 ', 8 ") are bent downwards (16, 17), such that these downwardly bent end parts (16, 17), when engaged with the upper, net-shaped bending reinforcement (9), center the spacers (8) and thus the reinforcement rods (5) connected to the latter and extending vertically downwards into the Mesh the bending reinforcement (9, 15) (Fig. 7). 11. shear reinforcement according to claim 1, characterized in that at least part of the downward ends of the vertically downwardly extending reinforcing bars (5) with spacers (18) for resting on the lower formwork when concreting the flat slab (2) and the Spacers (8), for example with wire (19), can be fixed to the upper bending reinforcement (9). 12. shear reinforcement element with a group of loading connected to a spacer 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 3rd 5 CH 683 545 A5 Reinforcing bars for shear reinforcement according to claim 1, characterized in that the spacer (8) intended to be arranged above the upper bending reinforcement (9) of the flat slab (2) to be reinforced zone by zone is curved or angled at least over part of its length, and that the reinforcing bars (5) fixedly connected to this spacer (8) and spaced apart in the longitudinal direction thereof run at least approximately perpendicular to this plane and are provided with a thickening head (6, 7) at each end. 13. A method for producing a shear reinforcement according to claim 1 by means of shear reinforcement elements according to claim 12, characterized in that according to the requirements of the shear cover a plurality of shear reinforcement elements with their reinforcement bars (5) extending downward from above in the area of the reinforcement Insert zones into the upper bending reinforcement (9) and then fix the spacers (8) to the upper bending reinforcement (9). 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 4th