EP0495334A1 - 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 shear reinforcement 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 cover with groups (a, b) of at least approximately perpendicular to the ceiling surface , inside the flat slab extending reinforcement bars 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 laborious 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 nets, can be laid in a simple manner from above, which enables the group-wise laying of interconnected reinforcement bars running perpendicular to the ceiling surface to be reinforced, and at the same time tipping the latter prevented in a very simple way when concreting.

This object is achieved according to the invention in a shear reinforcement of the type mentioned at the outset.

Appropriate 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.

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 using the drawing, for example. It shows:

Fig. 1

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

Fig. 2

a plan view of the shear reinforcement shown in Figure 1, only two reinforcement bar groups connected via spacers are shown for a better overview;

Fig. 3

a plan view analogous to Figure 2 of a second example of the spacer;

Fig. 4

a plan view analogous to Figure 2 of a third example of the spacer;

Fig. 5

a plan view analogous to Figure 2 of a fourth example of the spacer;

Fig. 6

a section along the line VI-VI in Figure 5;

Fig. 7

a section analogous to Figure 6 through a fifth example embodiment of the spacer; and

Fig. 8

a section analogous to Figure 6 through another example 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 slab 2 supported on supports 1 and made of reinforced concrete or prestressed concrete, zones in the area of these zones meet the requirements of shear coverage to increase the load-bearing capacity of zones subjected to shear forces 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 from 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 large number of shear reinforcement elements 5, 8 which can be used locally are shown in FIGS. 1 and 2.

For the simplest possible assembly of individual reinforcement bar groups a, b and for lateral support of the same to avoid an uncontrolled swiveling out of the reinforcement bars 5 during concreting, the latter are firmly connected to one another at their upper ends by a spacer 8, likewise 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 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 necessary, after the insertion of the individual shear reinforcement elements 5, 8 from above into the upper bending reinforcement 9, if the angled end sections 11 and 12 additionally have 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 V-shaped (FIG. 3) or wave-shaped (FIG. 4) in a horizontal plane, which means that when supported on the upper bending reinforcement 9 a very good positional stability of the reinforcing 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 each other, the ends 11', 11 '' and 12 'respectively adjacent to each other , 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 reinforcing bars 5 which extend vertically down to the region of the lower bending reinforcement 15 during 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 spacer 8 in question and thus the group of vertically downward-extending reinforcing 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 which can be concreted in, for resting on the lower formwork when concreting the flat slab 2, and then above the upper bending reinforcement 9 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)

Shear reinforcement 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 the shear cover with groups (a, b) of at least approximately perpendicular to the ceiling surface (4), inside the flat ceiling (2) is provided reinforcing bars (5), characterized in that the latter are provided with a thickening head (6, 7) at their upper and lower ends and in groups at their upper ends (6) One spacer (8) each is firmly connected to one another, the spacer (8) intended to rest on the upper bending reinforcement (9) or projecting over it extending in a horizontal plane, viewed at least over part of its length, being curved or angled. Shear reinforcement according to claim 1, characterized in that the end sections (11, 12) of at least one part of the individual spacers (8), preferably in opposite directions, lying in a horizontal plane, preferably at least approximately 90 °, are angled (FIG. 2). Shear reinforcement according to claim 1, characterized in that at least some of the individual spacers (8), viewed in a horizontal plane, are angled at least approximately in a V-shape (FIG. 3). Shear reinforcement according to claim 1, characterized in that at least some of the individual spacers (8), viewed in a horizontal plane, are undulating (Figure 4). Shear reinforcement according to one of claims 1 to 4, characterized in that the individual spacers (8), viewed in a horizontal plane, project at least two parallel and parallel bars of the upper bending reinforcement (9) for their lateral support (Fig. 2 and 5 to 7). Shear reinforcement according to one of claims 1 to 5, characterized in that the thickening heads (6, 7) of the reinforcing bars (5), which are firmly connected to the spacers (8) and run perpendicular to the ceiling surface (4), are at least approximately conical or truncated pyramid-shaped are. Shear reinforcement according to one of claims 1 to 6, characterized in that the spacers (8) and the reinforcement bars (5), preferably welded to them, are made of steel, preferably structural steel. Shear reinforcement according to claim 1, characterized in that the individual spacers (8) consist of at least two rod-shaped spacer elements (8 ', 8' ', preferably mild steel, which run at least approximately parallel to one another and are slightly spaced laterally from one another. Shear reinforcement according to claim 8, characterized in that the respectively adjacent ends (11 ', 11' 'of the two rod-shaped spacer elements (8', 8 '') are bent away from each other in a horizontal plane, preferably by at least approximately 90 ° each (Fig. 5 to 7). Shear reinforcement according to claim 9, characterized in that the ends (16, 17) of the bent parts (11 ', 11' ') of the rod-shaped spacer elements (8', 8 '') are bent downwards such that they are bent downwards End parts (16, 17), when engaging with the upper net-shaped bending reinforcement (9), centering the spacers (8) and thus the reinforcing bars (5) connected to the latter and extending vertically downwards in the meshes of the bending reinforcement (9, 15) cause. Shear reinforcement according to claim 1, characterized in that at least some of the downward ends of the vertically downwardly extending reinforcing bars (5) are provided with spacers (18) for resting on the lower formwork when concreting the flat slab (2) and the spacers ( 8), for example with wire (19), are fixed to the upper bending reinforcement (9). Shear reinforcement element with a group of reinforcement bars for shear reinforcement connected to a spacer according to claim 1, characterized in that the spacer (8) intended for arrangement above the upper bending reinforcement (9) of the flat slab (2) to be reinforced zone by zone is considered at least in a flat plane is curved or angled over part of its length, and that the reinforcing bars (5) which are fixedly connected to this spacer (8) and are spaced apart in the longitudinal direction thereof run at least approximately perpendicular to this plane plane and each end has a thickening head (6,7) are provided. Method for producing a shear reinforcement according to claim 1, characterized in that, according to the requirements of the shear cover, a plurality of shear reinforcement elements according to claim 11 with their reinforcing bars (5) extending downwards from above in the area of the zones to be reinforced into the upper bending reinforcement ( 9) and then fix the spacers (8), for example with wire, to the upper bending reinforcement (9).

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