WO2019073181A1

WO2019073181A1 - Device for connecting reinforcement bars for reinforced concrete and method for producing said device

Info

Publication number: WO2019073181A1
Application number: PCT/FR2018/052535
Authority: WO
Inventors: Elodie PAQUET; Sébastien Garnier; Benoït FURET; Romain PONSON
Original assignee: Universite De Nantes; Centre National De La Recherche Scientifique
Priority date: 2017-10-11
Filing date: 2018-10-11
Publication date: 2019-04-18
Also published as: FR3072106A1; EP3695070A1

Abstract

The present invention relates to a method for producing a device (10) for connecting two reinforcement bars (1) for reinforced concrete, the reinforcement bars comprising rough portions (2) on the outer surfaces thereof and conferring a high level of adhesion in concrete, the connection device comprising a tubular support (11) which is open at the two ends thereof and through which the two reinforcement bars are arranged end to end, the tubular support (11) having an inner diameter greater than the outer diameter of the ends of the reinforcement bars which are arranged in the connection device and comprising resilient oblique elements which are referred to as non-return elements (12) and which extend towards the interior of the tubular support and which are intended to cooperate with the rough portions of the ends of the reinforcement bars which are engaged in the tubular support so as to be bent during insertion of the ends of reinforcement bars in the tubular support and to prevent the withdrawal thereof after insertion into the tubular support, the method comprising the following steps: - cutting out a support from a steel plate and cutting, in the support, tongues that, by virtue of their size and position, form the non-return elements (12) of the device, - shaping the support so as to obtain the tubular support (11) of the connection device and - folding the tongues so as to form, in a manner projecting from the inner face of the tubular support, the non-return elements (12) of the device.

Description

DEVICE FOR CONNECTING REINFORCING BARS FOR ARMED CONCRETE

ITS MANUFACTURING METHOD

Technical field of the invention

The present invention relates to the field of building construction of reinforced concrete or traditional masonry (according to Eurocode 2 and 6). More particularly, it relates to a method of manufacturing a rebar connecting device or reinforcing elements for concrete.

State of the art

When constructing concrete buildings, it may be necessary or mandatory to join together metal reinforcements to achieve the construction by strata.

Different techniques are currently available to achieve this link.

A first technique, called overlap, consists in overlapping the ends of the reinforcing bars over a minimum length of six times the diameter of the bar according to the zone (earthquake resistant or not) of the construction and to fasten them together beforehand. pouring concrete. This technique involves leaving out relatively long expectations of up to 1 meter, which has disadvantages in terms of cost and staff safety.

Another technique is to achieve the mechanical connection of two ends of reinforcing bars by placing them end to end and connecting them by a sleeve or coupler providing mechanical continuity between the two reinforcing bars. Different achievements of this technique exist. For example, it is possible to make tapered threads at the ends of the reinforcing bars and to use a sleeve comprising two tapered threads for screwing said ends. An alternative is to replace the conical threads with cylindrical threads. This technique has the disadvantage of reducing the nominal diameter of the end of the reinforcing bars at the thread, which impacts the mechanical strength of the bars at their ends.

These two techniques also require that the connection be made before pouring concrete. It is impossible to make the connection while the concrete is still fresh.

Summary of the invention

An object of the invention is to provide a method of manufacturing a connecting device to overcome all or part of the aforementioned drawbacks and in particular to provide a connecting device that can be put in place after pouring concrete while the concrete is still fresh. This property is useful in some cases, especially for 3D printing of buildings.

For this purpose, the invention proposes a method for manufacturing a binding device for two reinforcement bars for reinforced concrete, said reinforcing bars having asperities on their external surfaces and conferring a high adhesion in the concrete, said connecting device comprising a tubular support open at both ends and through which the two reinforcing bars are arranged end to end, the tubular support having an inside diameter greater than the outside diameter of the ends of the reinforcing bars disposed in said device connecting and having elastic oblique elements, called non-return elements, extending inwardly of the tubular support and intended to cooperate with the asperities of the ends of the reinforcing bars engaged in said tubular support so as to bend to inserting said reinforcing bar ends into the tubular support and preventing the removal after insertion into the tubular support the process being remarkable in that it comprises the following steps: - Cutting a support in a steel plate and cutting, in said support, tongues dimensioned and positioned to form the non-return elements of said device,

forming said support so as to obtain said tubular support of the connecting device, and

- Folding tabs so as to form, projecting from the inner face of the tubular support, the non-return elements of said device.

Thus, in the case of reinforcing bars provided with oblique ridges, conventionally called locks, the non-return elements of the connecting device cooperate with the bolts of the ends of reinforcing bars to allow the insertion and then the blocking of the ends of the bars. reinforcement in the connecting device. In the case of reinforcing bars with recessed markings, the oblique elements cooperate with said markings. This provides a connection or junction complying with construction standards and whose installation is simplified on site.

According to a particular embodiment of the invention, the connecting device further comprising a stop extending substantially radially inside the tubular support for fixing the insertion length of the reinforcing bars in said connecting device, the method further comprises the following steps:

cutting, in said support, the abutment of said device,

- Folding the stop of said device.

Advantageously, the stop is disposed substantially in the middle of the tubular support.

According to a particular embodiment of the invention, the connecting device comprising, at one of its ends, a plug member to prevent the passage of aggregates in the connecting device before insertion of the reinforcing bars, the method comprises in in addition to the following steps:

cutting, in said support, the plug of said device,

- Folding the plug of said device. According to a particular embodiment, the connecting device is equipped, at at least one of its ends, with a guide cone to facilitate the insertion operation of the end of one of the bars of reinforcement in said connecting device, more particularly when the latter is embedded in an opaque medium such as fresh concrete. Advantageously, the device is equipped with a guide cone at both ends to facilitate and the insertion of the two reinforcing bars in the connecting device.

The invention also relates to a reinforcement for reinforced concrete comprising reinforcing bars, at least the ends of two of which are connected by means of a connecting device obtained by a method as defined above.

Brief description of the figures

Other advantages may still appear to those skilled in the art on reading the examples below, illustrated by the appended figures, given for illustrative purposes.

- Figure 1 is a view of a reinforcing bar for connecting to another reinforcing bar via the connecting device of the invention;

FIG. 2 is a perspective view of a connection device according to a first embodiment of the invention;

- Figure 3 is a schematic longitudinal sectional view of the connecting device of Figure 2;

- Figures 4 and 5 are views similar to Figures 2 and 3 wherein the connecting device according to the first embodiment is arranged between two reinforcing bars to ensure their connection;

FIG. 6 is a perspective view of a connection device according to a second embodiment of the invention;

- Figure 7 is a schematic longitudinal sectional view of the connecting device of Figure 6; FIG. 8 is a partial perspective view of a connection device according to a third embodiment of the invention; and

FIG. 9 is a view from above of the connecting device of FIG. 8.

Detailed description of the invention

FIG. 1 represents a reinforcing steel bar 1 with a high adhesion for reinforced concrete with a circular section, comprising, projecting from its outer surface, a plurality of asperities or ridges, commonly called locks 2, arranged obliquely. Each series of locks 2 extends over a semicircle (180 °) of the bar 2. Each series is separated from the neighboring series by a longitudinal rib 3 also protruding from the surface of the bar.

According to the invention, it is proposed to make the connection of two reinforcing bars 1 by placing them end to end and connecting them with the aid of a connecting device using the reinforcing bar locks to block and maintain the link.

Figures 2 to 5 illustrate a first embodiment of the connecting device of the invention. With reference to these figures, the referenced connection device 10 comprises a tubular support 1 1 open at its two ends and through which, when the connecting device is put in place to connect two reinforcing bars, are arranged end to end the two rebars 1.

The tubular support 1 1 extends in a longitudinal direction, the longitudinal direction being represented by the longitudinal axis L in the figures. Since the reinforcing bars are generally of circular section, the tubular support 1 1 is advantageously also of circular section. The tubular support 1 1 has an inside diameter greater than the outside diameter of the ends of the reinforcing bars 1. It comprises a plurality of elastic oblique elements, for example in the form of scales, called non-return elements 12, extending inwardly of the tubular support.

The non-return elements 12 are intended to cooperate with the latches 2 of the ends of the reinforcing bars so as to bend at the insertion of said ends of reinforcing bars into the tubular support and to prevent their removal after insertion into that -this.

In the case of reinforcing bars with recessed markings, instead of the locks 2, the non-return elements 12 cooperate with these markings. The non-return elements 12 are distributed over the entire circumference of the tubular support January 1. They are positioned to cooperate with the bolts 2 of the reinforcing bars. Their positions therefore depend on the position of the rebar locks.

In the example of the embodiment of FIGS. 2 to 5, the connecting device comprises 12 non-return elements cooperating with each end of the reinforcing bar, divided into 4 groups of 3 non-return elements aligned longitudinally on the circumference of the tubular support. 1 1. In this example, the groups of non-return elements are shifted transversely by 90 degrees. Of course, other distributions in number and position as well as other forms of the non-return elements are conceivable.

When inserting the end of a reinforcing bar 1 in the connecting device 10, the non-return elements 12 rise up when the locks 2 pass and then return in place.

In the figures, the flake-shaped non-return elements 1 1 have an edge B1 perpendicular to the axis L and two lateral edges B2,

B3 extending in a rounded downward or upward direction when the device is disposed vertically.

From a dimensional point of view and for illustrative purposes, the connecting device 10 has a length sufficient to have an adhesion of reinforcing bars in the device and a tensile and compressive strength corresponding to the construction standards in force. The length of the connecting device is adjustable from 200 to 600mnn and is also consistent with the standard of Eurocode 2 and 6 which stipulates that the overlap length should be 4 and 6 times the diameter of the next rebar the area (earthquake or non-earthquake) of the building.

According to an advantageous embodiment illustrated by FIGS.

5, the connecting device 10 is made in one piece. More particularly, it is made from a plate or sheet of a given thickness, for example between 2 and 8 mm, of a metal alloy, such as for example a steel, having compressive strength properties defined for withstand the compression forces provided on the rebars.

Each non-return element 1 1 is made by cutting the plate (for example, laser cutting) along the lateral edges B2, B3 of the non-return element and folding the steel plate along the edge B1. The anti-return elements are cut in such a way as to correspond, after insertion of the reinforcing bars in the connecting device, to reinforcing bars of the reinforcing bars. The anti-return elements 1 1 thus formed leave negative recesses 13 in the support. In order to prevent these recesses 13 from excessively weakening the tubular support 11, the size of the recesses and the spacing between two adjacent recesses are defined to withstand the compression and tensile forces provided on the reinforcement bars. .

Figures 6 and 7 illustrate a second embodiment. In this embodiment, the connecting device 10 further comprises a stop 14 extending substantially radially inside the tubular support January 1 to limit the insertion length of the reinforcing bars in said connecting device. In this embodiment, the stop 14 is disposed substantially in the middle of the tubular support 1 1 so that the connected rebar has substantially the same insertion length in the connecting device. The reinforcing bars to be connected are preferably inserted so that their ends are in contact with the stop 14, if necessary by rotating the bar or the connecting device around its longitudinal axis.

In the case of a one-piece connecting device, the abutment 14 may be made according to the same process as for the non-return elements. A tongue is cut in the tubular support 1 1, which is then folded inwardly of the tubular support 1 1 and positioned perpendicularly to the longitudinal axis L. According to a particular embodiment, it is cut and folds two diametrically opposite tabs on the tubular support 1 1 so as to obtain a double stop or a stop in two parts.

In the embodiment of FIGS. 6 and 7, the tubular support 1 1 is equipped, at at least one of its ends, with a guide cone 15 to facilitate the insertion operation of the end of FIG. at least one of the reinforcing bars in said connecting device when the latter is embedded in an opaque medium such as fresh concrete.

The guide cone 15 is more exactly of frustoconical shape. The small base of the truncated cone is connected to one end of the tubular support January 1 and therefore has a diameter equal to the diameter of the tubular support.

If the connection of the two reinforcing bars is carried out before pouring the concrete, the guide cone may also help the operator to introduce the second reinforcing bar into the connecting device.

Advantageously, the connecting device of the invention further comprises, at one of its ends, a cap member to prevent the passage of concrete aggregates, such as gravel, in the connecting device before insertion of the bars. frame. Figures 8 and 9 illustrate an embodiment of the connecting device comprising such a plug. In this embodiment, the plug, referenced 16, is cut in the tubular support January 1. This plug is intended to close at least partially one end of the connecting device 10. It therefore advantageously has a generally circular shape when the tubular support 1 1 is of circular section. It comprises for example a disc 160 attached by a lug 161 at the end of the tubular support January 1. The diameter of the disk 160 is slightly smaller than that of the tubular support 11. The disc 160 and the side edges of the lug 161 are advantageously cut into the wall of the tubular support 1 1 as shown in Figures 8 and 9 in order to achieve the connecting device 10 of the monobloc type. After cutting, the tab 161 is folded so as to position the disc 160 inside the tubular support substantially perpendicular to the longitudinal axis L.

In a general manner and in the case of a monobloc embodiment, the method of manufacturing the connecting device of the invention comprises the following steps:

cutting of the support in a steel plate and cutting, in said support, of tongues sized and positioned to form the non-return elements and, if appropriate, stop and plug of said device,

forming said support, for example by winding around a cylinder and then welding adjacent opposite edges, so as to obtain a tubular support extending along the longitudinal axis L, and

- Folding the tabs so as to form, projecting from the inner face of the tubular support, the non-return elements and optionally abutment and plug of said device.

In terms of use, the connecting device 10 is used in the following manner when a reinforcing bar is waiting and is to be connected with another reinforcing bar. The connecting device 10 on the free end of the rebar waiting, before the casting operation of the concrete. It is depressed until the end of the reinforcing bar is in contact or substantially in contact with the stop 14 of the device and the withdrawal of the connecting device is prevented by the non-return elements. After pouring the concrete, the end of the other reinforcing bar is pressed into the fresh concrete in the area where the connecting device is embedded. The guiding cone will then serve to guide the end of the new bar reinforcement to the tubular support of the connecting device. This new reinforcing bar is depressed until its end is in contact or substantially in contact with the stop of the device and the removal of the bar is prevented by the non-return elements of the device.

The invention is described in the foregoing by way of example. It is understood that one skilled in the art is able to achieve different embodiments of the invention, for example by combining the various characteristics above taken alone or in combination, without departing from the scope of the invention. .

Claims

1) A method for manufacturing a connecting device (10) for two reinforcement bars (1) for reinforced concrete, said rebar having asperities (2) on their outer surfaces and imparting high adhesion in the concrete said connecting device comprising a tubular support (1 1) open at both ends and through which the two reinforcing bars are arranged end to end, the tubular support (1 1) having an inside diameter greater than the outside diameter of the ends of the reinforcing bars arranged in said connecting device and comprising elastic oblique elements, called non-return elements (12), extending towards the inside of the tubular support and intended to cooperate with the asperities of the ends of the reinforcing bars engaged in said tubular support so as to bend at the insertion of said reinforcing bar ends into the tubular support and to prevent withdrawing after insertion into the tubular support, the method being characterized in that it comprises the following steps:

- Cutting a support in a steel plate and cutting, in said support, tongues dimensioned and positioned to form the non-return elements (12) of said device,

forming said support so as to obtain said tubular support (1 1) of the connecting device, and

- Folding tabs so as to form, projecting from the inner face of the tubular support, the non-return elements (12) of said device.

2) Method according to claim 1 characterized in that the connecting device (10) further comprising a stop (14) extending substantially radially inside the tubular support to fix the insertion length of the bars of reinforcement in said connecting device, the method further comprises the following steps:

- cutting, in said support, the stop (14) of said device,

- Folding the stop (14) of said device. 3) Method according to claim 1 or 2 characterized in that the connecting device (10) comprising, at one of its ends, a plug member to prevent the passage of aggregates in the connecting device before insertion of the bars reinforcement, the method further comprises the following steps:

- cutting, in said support, the plug (16) of said device,

- Folding the cap (16) of said device.

4) Reinforced concrete reinforcement comprising reinforcing bars, of which at least the ends of two of them are connected by means of a connecting device obtained by a method according to any one of Claims 1 to 3. .