EP2108759A2 - Muffle connection for concrete reinforcement rods - Google Patents

Abstract

The sleeve joint (1) has concrete reinforcing bars (2) connected to a sleeve part (3) by a connecting end. Elasticity modules of the reinforcing bars are different from each other. The sleeve part has a recess (4) for receiving the concrete reinforcing bar with a relatively low elasticity module and a junction, particularly a recess (5) for another concrete reinforcing bar with a relatively high elasticity module. An additional inner structure (6) is formed, which interacts with complimentary structure (7) at the connection end of the former concrete reinforcing bar.

Description

The present invention relates to a socket joint for concrete reinforcing rods of materials having mutually different moduli of elasticity, in particular for a reinforcing steel bar and a bar of fiberglass reinforced plastic, wherein the concrete reinforcing bars are each connected to a connecting end with a sleeve part, which at least a first recess for receiving a first concrete reinforcing bar having a relatively lower modulus of elasticity and a further connection point, in particular a second recess for a second concrete reinforcement rod having a relatively higher modulus of elasticity.

Such socket joints or sleeve parts for creating such compounds are known. In this case, the sleeve parts may also be formed in two parts in the manner of a Male- and a female-female part, such as from the EP 1 277 892 A1 or the DE 201 10 720 known.

As a rule, the concrete reinforcing bars to be connected and the sleeve part or the sleeve parts are made of steel and thus have essentially the same material properties, in particular elasticity modules, so that there is generally no relative slip between the connected components under load the emergence of which in principle a modulus of elasticity difference is required.

However, the applicant has in the past strengthened instead of steel, especially stainless steel, and glass fiber reinforced plastic in rod form for Concrete reinforcement used, which are characterized in particular with respect to stainless steel by a lower thermal conductivity and reduced procurement costs. In addition, said glass fiber rods are relatively easy to drill or machine, resulting in further advantages in the application, especially in tunneling.

However, a particular problem arises at the junction between the aforementioned glass fiber rods and conventional reinforcing steel rods, because the said glass fiber reinforced plastic on the one hand and steel on the other hand have very different elastic moduli, which may differ in practice, for example by a factor of 3.5. As already stated above, such an elastic modulus difference can lead to a slip at the connection point, so that such connections do not have optimum load resistance. Since the quotient of stress and modulus of elasticity is integrated over the path to determine the slip, an increased overlap length in the connection region of GRP and steel by a correspondingly formed sleeve part is not helpful, but rather rather counterproductive.

Proceeding from this, the present invention seeks to further develop a socket joint of the type mentioned in that a secure and firm connection of concrete reinforcing bars is made possible, which consist of materials with mutually different moduli of elasticity.

The invention achieves the object by means of a socket connection with the features of the appended patent claim 1.

Advantageous developments of the subject invention are specified in the dependent claims, the wording of which is hereby incorporated by express reference in the description in order to avoid unnecessary text repetition.

According to the invention, a socket connection for concrete reinforcing rods of materials with mutually different moduli of elasticity, in particular for a reinforcing steel bar and a bar of glass fiber reinforced plastic, wherein the concrete reinforcing bars are each connected to a connecting end with a sleeve part, which at least a first recess for receiving a first concrete reinforcing bar with a relatively lower modulus of elasticity and another connection point, in particular a second recess for a second concrete reinforcing bar having a relatively higher modulus of elasticity, characterized in that within the first recess at least one additional inner structure is formed, which cooperates with complementary structures on the used in the sleeve part connecting end of the first concrete reinforcing bar surface.

According to a basic idea of the present invention, the formation of said internal structure of the sleeve part and the complementary structures at the connecting end of the first concrete reinforcing bar creates an enlarged contact or activation surface between the concrete reinforcing bar and the sleeve part, resulting in an improved load behavior, which in particular a comparison with conventional constructions significant reduction of the overlap length between the sleeve part and inserted concrete reinforcement rod can go along. Said additional activation, together with the reduced overlap length, contributes to a significant reduction in slip, resulting in a secure and strong connection between the sleeve part and said concrete reinforcing bar, and then another concrete reinforcing bar connectable to the other end of the sleeve part to provide the complete sleeve connection is.

Said second recess for receiving the second concrete reinforcing bar according to the invention is not absolutely necessary. For example, may alternatively be provided to stick a sleeve part only with first recess on the connecting end of the second reinforcing bar.

The inner structure may be formed in a development of the present invention as a projecting into the first recess geometric body, such as a truncated cone, a hollow circular cylinder section, a number of fins, pins or the like. The complementary structures at the connection end of the first concrete reinforcing bar are preferably formed in the curing state of the GRP material according to this.

A preferred development of the invention consists in that the sleeve part in the region of the first recess has a reduced material thickness compared to the rest of the sleeve part, in particular a reduced outside diameter. This measure also contributes to avoiding slippage.

Another development of the present invention provides that, in order to reduce its material thickness, the sleeve part in the region of the first recess tapers substantially frustoconically towards its end, wherein, however, the taper is also not limited to straight or flat flanks of the sleeve part. For example, the outer flanks of the sleeve part in the tapering region can also be formed in particular concavely curved.

Advantageously, the inner structure is formed and / or arranged symmetrically with respect to the longitudinal axis of the sleeve part or of the entire sleeve connection. Specifically, the inner structure may be formed in a development of the present invention rotationally symmetrical relative to the longitudinal axis of the sleeve part or the sleeve connection.

Another development of the subject invention provides that the inner wall of the first recess is formed complementary to an opposite wall of the inner structure. These include in particular embodiments in which said inner wall of the first recess and an opposite wall of the inner structure are respectively oriented parallel to the longitudinal axis of the sleeve part and the sleeve connection. However, it is also possible to align both the said inner wall and the opposite wall of the inner structure with respect to the longitudinal axis of the arrangement inclined.

To increase the connection security, an extremely preferred embodiment of the present invention provides that at least one thread and in the first recess at the connecting end of the first concrete reinforcing bar of the sleeve part and / or on the inner structure at least one corresponding mating thread is provided. Advantageously, the recess has a first internal thread and the internal structure has a first external thread. Complementary to this, the connecting end of the concrete reinforcing rod has first an external thread, which cooperates with the first internal thread of the sleeve part, and a second internal thread, which cooperates with the external thread of the inner structure of the sleeve part.

In particular, when in the formation of the socket joint adhesive, such as synthetic resin or the like, is used, it is advantageous if said thread and the corresponding mating thread have different pitches and / or a certain offset to each other, that is, "arranged on a gap", to better distribute the adhesive.

To avoid the occurrence of a slip problem at the other end of the sleeve part, another preferred embodiment of the present invention provides that the sleeve part is formed in a material which substantially corresponds to the material of the second concrete reinforcement rod.

Figur 1

eine erste Ausgestaltung der erfindungsgemäßen Muffenverbindung im getrennten Zustand;

Figur 2

einen Schnitt entlang der Linie B-B in Figur 1;

Figur 3

einen Schnitt entlang der Linie C-C in Figur 1;

Figur 4

die Ausgestaltung der erfindungsgemäßen Muffenverbindung gemäß Figur 1 im zusammengesetzten Zustand;

Figur 5

einen Schnitt entlang der Linie A-A in Figur 4;

Figur 6

eine weitere Ausgestaltung der erfindungsgemäßen Muffenverbindung im getrennten Zustand;

Figur 7

einen Schnitt entlang der Linie B-B in Figur 6;

Figur 8

einen Schnitt entlang der Linie C-C in Figur 6;

Figur 9

die Muffenverbindung gemäß Figur 6 im zusammengesetzten Zustand;

Figur 10

einen Schnitt entlang der Linie A-A in Figur 9;

Figur 11

eine weitere Ausgestaltung der erfindungsgemäßen Muffenverbindung im getrennten Zustand;

Figur 12

einen Schnitt entlang der Linie B-B in Figur 11;

Figur 13

einen Schnitt entlang der Linie C-C in Figur 11;

Figur 14

die Muffenverbindung gemäß Figur 11 im zusammengesetzten Zustand; und

Figur 15

einen Schnitt entlang der Linie A-A in Figur 14.

Further features and advantages of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawing. It shows:

FIG. 1

a first embodiment of the socket joint according to the invention in the separated state;

FIG. 2

a section along the line BB in FIG. 1 ;

FIG. 3

a section along the line CC in FIG. 1 ;

FIG. 4

the embodiment of the sleeve joint according to the invention FIG. 1 in the assembled state;

FIG. 5

a section along the line AA in FIG. 4 ;

FIG. 6

a further embodiment of the socket joint according to the invention in the separated state;

FIG. 7

a section along the line BB in FIG. 6 ;

FIG. 8

a section along the line CC in FIG. 6 ;

FIG. 9

the socket connection according to FIG. 6 in the assembled state;

FIG. 10

a section along the line AA in FIG. 9 ;

FIG. 11

a further embodiment of the socket joint according to the invention in the separated state;

FIG. 12

a section along the line BB in FIG. 11 ;

FIG. 13

a section along the line CC in FIG. 11 ;

FIG. 14

the socket connection according to FIG. 11 in the assembled state; and

FIG. 15

a section along the line AA in FIG. 14 ,

FIG. 1 shows an embodiment of the socket joint according to the invention for concrete reinforcement rods of materials with mutually different elastic moduli, which is designated as a whole by the reference numeral 1. The socket joint 1 is in FIG. 1 shown in the separated state, in which the concrete reinforcing bars, of which in FIG. 1 only one is shown explicitly, not inserted into the actual sleeve part 3. The sleeve joint 1 is particularly suitable for connecting a reinforcing steel bar with a rod 2 made of glass fiber reinforced plastic (GRP), since the materials mentioned have particularly different elastic moduli.

The sleeve part 3 has for this purpose a first recess 4 and a per se optional second recess 5, which are formed at opposite ends of the sleeve part 3. The first recess 4 serves to receive the illustrated concrete reinforcing bar 2, which has the relatively lower modulus of elasticity. The second recess 5 serves to receive a second concrete reinforcement bar (not shown), which has the higher modulus of elasticity with respect to the concrete reinforcement bar 2.

The sleeve part 3 is preferably formed in a material which, in particular with regard to the modulus of elasticity, has comparable properties to the material of the second concrete reinforcement bar, not shown, wherein the said material is preferably a suitable steel. In particular, for this reason, the sleeve part 3 and the second reinforcing bar alternatively be connected to each other by simple gluing, so that accordingly no second recess is required.

To avoid slippage in the connecting region of the first concrete reinforcing bar 2 and the sleeve part 3 due to the existing modulus of elasticity difference, the sleeve part 3 in the region of the first recess 4 has a reduced material thickness compared to the rest of the sleeve part 3. For this purpose, the sleeve part 3 is formed in said region with a reduced outer diameter decreasing towards the corresponding end of the sleeve part 3.

In order to be able to further reduce the overlap length ÜL of the first concrete reinforcing bar 2 and of the sleeve part 3, the embodiment of the socket joint 1 shown further provides that within the first recess 4 an additional internal structure 6 is formed, which in the present case has an in represents the first recess 4 projecting truncated cone, in particular the sectional view in FIG. 3 can be seen. At the connection end of the first concrete reinforcing bar 2 to be inserted into the recess 4, a structure 7 complementary to the internal structure 6 of the sleeve part 3 is designed in the form of a frusto-conical recess, so that said structures 6, 7 interact in a planar manner when the concrete reinforcing bar 2 is inserted into the sleeve part 3 , The term "surface interaction" means in this case that on the inner structure 6 and the complementary structure 7 an enlarged contact or contact surface between the concrete reinforcement bar 2 and the sleeve part 3 is created, so that despite the relatively short overlap length ÜL improved material activation for voltage transmission caused, which in turn contributes to slip reduction.

Hereinafter, for further structural details of the embodiment according to FIG. 1 with reference also to the FIGS. 2 and 3 Reference is made.

The inner structure 6 of the sleeve part 3 and the complementary structure 7 of the concrete reinforcing bar 2 are arranged or formed symmetrically to the longitudinal axis L of the sleeve joint 1 shown.

The concrete reinforcing bar 2, which is preferably formed in said glass fiber reinforced plastic (GRP), has a conically tapered connection end, wherein the first recess 4 of the sleeve part 3 is formed correspondingly complementary. This special shape further contributes to an ideally linear load profile in the contact or connection area.

In addition, the concrete reinforcing bar 2 at its connection end, first an external thread 8 and the sleeve part 3 in the region of the first recess 4 has a corresponding internal thread 9. Furthermore, the concrete reinforcement rod 2 has in the region of the complementary structure 7 an additional internal thread 10 (cf. FIG. 2 ), while the inner structure 6 of the sleeve part 3 a correspondingly complementary external thread 11 (see. FIG. 3 ) is provided. The threads of the concrete reinforcing bar 2 on the one hand and the sleeve part 3 on the other hand can be offset from each other and / or formed differently with respect to their pitches to ensure a secure connection of said components - especially if these by introducing an adhesive, such as synthetic resin, in the first Recess mediated or supported.

Due to the alternating in the transverse direction inner and outer surfaces (surfaces of the inner structure 6 and the outer structure 7) occurs in this way in particular to a mutual "disability" of reinforcing rod 2 and sleeve part 3 because of the occurring during tensile and / or compressive stress transverse contraction , Particularly effective in this context are surfaces in which the first reinforcing bar 2 is obstructed towards the outside and the sleeve part 3 is obstructed inwards with respect to the transverse contraction, as for example in the embodiment according to the attached drawings FIG. 5 (see below).

Also in the region of the second recess 5, which - as I said - for receiving the second concrete reinforcing bar, not shown, a thread 12 is provided, which may be formed for connection to the concrete reinforcing bar, not shown in a conventional manner.

FIGS. 4 and 5 show the above with reference to the FIGS. 1 to 3 explained in detail embodiment of the socket joint according to the invention in the assembled state and under suggestion of the second concrete reinforcing bar 2 ', with the corresponding figures otherwise not be discussed.

The following FIGS. 6 to 10 show a further embodiment of the socket joint 1 according to the invention, in the present case for the sake of brevity only on the essential differences from the above-detailed embodiment according to the FIGS. 1 to 5 will be discussed in more detail.

As shown in the FIGS. 4 to 6 the sleeve part 3 and the concrete reinforcing bar 2 are formed with an even shorter overlapping area ÜL '. The cross-section or radius decrease a of the sleeve part is also according to FIG. 6 significantly more pronounced than in the FIGS. 1 to 5 ,

For this purpose, an inner structure 6 is formed in the region of the first exception 4 of the sleeve part 3, which in cross-section (see. FIG. 8 ) is in turn formed as a truncated cone as a whole, but additionally has a central, also frusto-conical recess 13, which is oriented just inversely to the truncated cone-like course of the remaining inner structure 6.

The structure 7 at the connection end of the concrete reinforcing bar 2 is in turn formed complementary to the above-described inner structure 6 and consists for this purpose of a conical recess (see. FIGS. 1 to 5 ), in which, however, a conical projection 14 which projects in the opposite direction, which is designed to engage in the additional recess 13 of the sleeve part 3, projects centrally.

Unlike the subject of the FIGS. 1 to 5 In the present case, the concrete reinforcing rod 2 does not taper at its connecting end, and also the outer wall 15 of the recess 4 of the sleeve part 3 extends in a complementary manner parallel to the longitudinal axis L of the socket joint 1.

In this way, there is again a large-scale interaction between concrete reinforcement rod 2 and sleeve part 3 in the connection region, which contributes to an improved material activation, so that the overlap area ÜL 'can be reduced and the slip can be reduced.

The FIGS. 9 and 10 show the embodiment of the sleeve joint 1 described above in detail in the assembled state.

As with the subject of FIGS. 1 to 5 can be provided at the connection end of the concrete reinforcement rod 2 and in the region of the first recess 4 of the sleeve part 3 suitable, complementary thread means, which are not shown here for reasons of clarity.

The following FIGS. 11 to 15 show a further embodiment of the socket joint 1 according to the invention, again in turn only essential differences compared to the embodiments already described will be discussed.

The in the FIGS. 11 to 15 The embodiment shown essentially corresponds to that according to FIGS FIGS. 6 to 10 , wherein only the projecting structures in the region of the first recess 4 of the sleeve part 3, which form the said inner structure 6, with parallel to the longitudinal axis L of the sleeve joint 1 oriented walls 16, 17 are formed. Overall, this results in the appearance of a hollow circular cylindrical portion for the inner structure 6, while the structure 7 is formed correspondingly complementary at the terminal end of the concrete reinforcing bar 2, as shown in the figures.

In the region of the recess 4 and the connection end of the concrete reinforcing bar 2, in turn, threaded means can be provided, which in the FIGS. 11 to 15 is not explicitly shown.

It should be noted that the present invention is not limited to the rotationally symmetrical embodiments described above by way of example. For example, the inner structure 6 may also be formed in the form of a preferably uniform grid of lamellae, pins or the like, which cooperate with corresponding complementary structures (receptacles) at the attachment end of the concrete reinforcement bar 2 in order to create the largest possible contact surface.

Claims (14)

Muff joint (1) for concrete reinforcing bars (2) made of materials with mutually different elastic moduli, in particular for a reinforcing steel bar (2 ') and a bar (2) made of glass fiber reinforced plastic, in which the concrete reinforcing bars (2) each with a connecting end with a sleeve part (3 ) having at least a first recess (4) for receiving a first concrete reinforcing bar (2) having a relatively lower modulus of elasticity and another joint, in particular a second recess (5) for a second concrete reinforcing bar (2 ') having a relatively higher modulus of elasticity having,
characterized,
in that at least one additional inner structure (6) is formed inside the first recess (4), which interacts with complementary structures (7) on the connecting end of the first concrete reinforcement bar (2) inserted into the sleeve part (3). A socket joint (1) according to claim 1,
characterized,
that the sleeve part (3) in the region of the first recess (4) with respect to the remaining sleeve part (3) reduced material thickness, in particular having a reduced outer diameter. A socket joint (1) according to claim 1 or 2,
characterized,
in that , in the region of the first recess (4), the sleeve part (3) tapers substantially frusto-conically toward its end (a). Socket joint (1) according to at least one of claims 1 to 3,
characterized,
that the inner structure (6) is symmetrical with respect to the longitudinal axis (L) of the sleeve part (3) and / or arranged. Socket joint (1) according to at least one of claims 1 to 4,
characterized,
that the internal structure (6) rotationally symmetrical with respect to the longitudinal axis (L) of the socket member (3) is formed. Sleeve connection (1) according to at least one of claims 1 to 5,
characterized,
that the internal structure (6) than in the first recess (4) is formed in projecting truncated cone. Sleeve connection (1) according to at least one of claims 1 to 5,
characterized,
in that the inner structure (6) is designed as a hollow circular cylinder section projecting into the first recess (4). Sleeve connection (1) according to at least one of claims 1 to 5,
characterized,
that the internal structure (6) is formed from a number of fins, pins, or the like. Socket joint (1) according to at least one of claims 1 to 8,
characterized,
in that the inner wall (15) of the first recess (4) is designed to be complementary to an opposite wall (17) of the inner structure (6). Socket joint (1) according to at least one of claims 1 to 9,
characterized,
that at the connecting end of the first concrete reinforcing rod (2) at least one thread (8, 10) is provided and that in the first recess (4) of the socket member (3) and / or on the inner structure (6) at least one corresponding counter-thread (9, 11) is provided. Socket joint (1) according to at least claim 10,
characterized,
that the thread (8, 10) and the counter-thread (9, 11) have different pitches and / or a certain amount of offset to each other. Socket joint (1) according to at least one of claims 1 to 11,
characterized,
that the sleeve part (3) in the region of the second recess (5) is formed substantially smooth cylindrical with a constant outer cross-section. Socket joint (1) according to at least one of claims 1 to 12,
characterized,
in that the sleeve part (3) is formed in a material, in particular steel, substantially corresponding to the material of the second concrete reinforcing bar (2 '). Socket joint (1) according to at least one of claims 1 to 13,
characterized,
in that at least the first concrete reinforcing bar (2) is glued into the sleeve part (3).

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