GB2183767A

GB2183767A - Sealing stirrup and its fixing method

Info

Publication number: GB2183767A
Application number: GB08625372A
Authority: GB
Inventors: Marcel Bergdoll
Original assignee: MATERIEL SECURITE URB
Current assignee: MATERIEL SECURITE URB
Priority date: 1985-10-23
Filing date: 1986-10-23
Publication date: 1987-06-10
Also published as: GB2183767B; HK100290A; GB8625372D0; FR2588912B1; GR3000042T3; ATE39537T1; EP0223725B2; ES2006681B3; SG78490G; DE3661563D1; EP0223725A1; EP0223725B1; JPS62101756A; FR2588912A1; ES2006681T5

Abstract

Tubular stirrup designed to be fixed in the wall of a concrete structure and that consists of a U- shaped tubular element (2) made, in particular, of metal, and of one or of several fixing bushes (7) fitted to the ends (9, 10) of the tubular element (2), with the latter U-shaped element featuring at its ends (9, 10) a peripheral bead (11) in the shape of a step obtained by swaging the aforesaid ends (9, 10) and co- operating with the inside wall (12) of each fixing bush (7). <IMAGE>

Description

1 1 1 GB2183767A 1

SPECIFICATION

Sealing stirrup and its fixing method The invention concerns a tubular stirrup designed to be fixed in the wall of a concrete structure and that consists of a U-shaped metal tubular element and of two or of several fixing bushes fitted to the ends of the tubular element.

The invention also concerns the fixing method for the aforesaid sealing stirrup in the wall of a concrete structure.

We already know from the former state of the technique, stirrups designed for similar use and that consist, in general, of a tubular element that features the shape of a -U-, with the end of the legs designed to be positioned in the wall of a brickwork wall through the intermediate of plastic material bushes.

Thus through document FR-A-2071 601, we know a stirrup that consists of a steel tube provided with a plastic material or aluminium cover to prevent corrosion, with this tube in- stalled in brickwork or in a concrete wall by means of attached fixing elements that consist here of plastic material bushes provided on the outside with ring-shaped ribs.

The fixing of this type of stirrup according to the aforesaid document consists in inserting fixing bushes into corresponding holes drilled previously in the brickwork, then in forcing the ends of the tubular element of the stirrup into the already installed fixing bushes.

The tubular stirrup and its fixing method according to this document have several drawbacks.

As a matter of fact, before the tubular element can be installed in the fixing bushes, appropriate holes have to be drilled for the latter in hard and dry concrete of the structures to be fitted. This is rendered particularly critical because the holes have to feature an accurate and constant diameter as otherwise the quality of the stirrup fixation will vary.

Furthermore, the installation of the stirrup as described above requires important means applied to drive the ends of the bent tubular body into the bushes.

The draw-out resistance of this type of stir- 115 rup with regard to the linkage bushes can not be greater that the force applied for driving the aforesaid stirrup into the bushes. Actually, it is very frequently possible to pull out the tubular element by applying a tractive force considerably below specified standard level i.e. 360 kg. The result is a risky and even dangerous use of certain stirrups installed according to the specifications of this patent.

We know, in addition, through document FR-A-2440461, a safety stirrup that also consists of a tubular element bent in the shape of a -U- and the ends of which carry plastic material bushes designed to be installed in a concrete wall.

In this case, the fixing bushes feature a cone-shaped end section that possibly allows for installing these bushes in the fresh concrete of a wall being cast.

However, the linkage between the ends of the tubular element and the fixing bushes is also provided by simple tightening, with the inherent risks to the strength of the entire unit. This risk is made greater by the fact that the fixing bushes are made of plastic material and the tubular element of metal, with different coefficients of expansion which, consequently, significantly affects the tightening forces applied to the metal tubular element and, consequently, the strength of the latter.

It has been considered, furthermore, that the draw-out resistance of the heat tubular element could be improved by glueing the ends of this element in the fixing bushes. This method, however, requires the use of a special glue with a critical method of application, resulting in excessive manufacturing and installation costs for the stirrup involved.

In addition, tests have shown that this solu- tion would allow to achieve a draw-out resistance of 360 to 380 kg only, i.e. the specified standard level without any safety coefficient.

The object of this invention is to remedy these drawbacks. The invention as characterized in the claims solves the problem that consists in making a tubular stirrup designed to be fixed in the wall of a concrete structure, which stirrup consists of a U-shaped tubular element made of metal, and of two or more fixing bushes fitted to the ends of the tubular element, with the latter bent to U-shape featuring at its ends a peripheral step-shaped bead obtained by chasing the aforesaid ends and co-operating with the inside wall of each fixing bush.

The benefits from this invention consist essentially in that the chased metal of the ends of the bent element will literally dig into the inside wall of each fixing bush when the user climbs a vertical wall fitted with these stirrups and grips the stirrup above to pull himself up by applying a pulling effort on the latter. According to tests carried out, the draw-out resistance may be as high as 600 and even 700 kg. Thus, this stirrup features a draw-out resistance significantly better than that of stirrups known from the former state of the technique.

The invention will be detailed below by means of drawings that show one method of execution only.

Figure 1 shows the plan view of a stirrup according to the invention with this stirrup sealed into a concrete wall.

Figure 2 shows the lateral and the sectional view of one of the stirrup ends installed in a fixing bush.

Figure 3 shows a detail view of part -A- schematized in Fig. 2.

2 GB 2 183 767A 2 We are referring to Fig. 1.

The sealing stirrup 1 according to the invention consists, in a wellknown manner, of one tubular element 2 bent to U-shape and the two legs 3 and 4 of which are designed to be 70 fixed in a concrete wall 5. According to the invention, this fixing will be performed either in hard and dry concrete of an existing structure or in fresh concrete of a concrete wall being cast.

In the first case, suitably spaced holes 6 are drilled into the wall 5. In these holes 6 are then installed fixing bushes 7 that are simply driven into the holes 6 until a peripheral shoul- der 8 of the fixing bushes 7 stops their progression in the holes 6.

In the second case, the bushes 7 are previously slipped onto the ends 9 and 10 of the legs 3 and 4 of the tubular element 2, then the entire system is inserted into the concrete wall 5 being cast, as shown by Fig. 1.

We are referring to Figs. 2 and 3.

Obviously it is necessary, in view of making the installation of the sealing stirrup according to the invention easier and of ensuring the latter's resistance against stress and deterioration in time, to provide for means that, firstly, make the installation of the stirrup easier and, secondly, provide this stirrup with extremely reliable fit that will yield only under very great strain.

For this purpose, the tubular element 2 is provided at its ends 9 and 10 with fixing means in relation with the fixing bushes 7.

According to one version shown by Fig. 2, these fixing means consist of a peripheral bead 11 provided close to the ends 9 and 10 of the tubular element 2 and that co-operates with the inside wall 12 of each fixing bush 7.

This peripheral bead 11 is obtained by chas- 105 ing the aforesaid ends.

As the fixing bush 7 may be made of plas tic material, this peripheral bead 11 will prefer ably have the shape of a peripheral step in relief as compared to the outside wall 13 of 110 the tubular element 2 and recessed as com pared to the ends 9 and 10 of the legs 3 and 4 of the aforesaid tubular element 2. In addi tion, each of the fixing bushes 7 has at its opening 14 a peripheral guide clearance 15.

Thus, when the ends 9 and 10 of the legs 3 and 4 of the tubular body 2 are inserted into the fixing bushes 7, these ends 9 and 10 provided with their peripheral step will be po- sitioned in front of the guide clearances 15.

Pressure applied to the tubular element 2 then forces the ends 9 and 10 into the fixing bushes 7 with these ends deforming elastically the walls 16 provided possibly with peripheral ribs known as such. Then the ends 9 and 10 125 abut against the coneshaped part 18 of the fixing bushes 7. In this position, the design chosen for the peripheral bead 11 will have any attempt at pulling out the tubular element 2 result in having the aforesaid peripheral 130 bead 11 dig into the wall 16 of the fixing bushes 7, which will cause the fixation of the stirrup to become even more effective.

To note that the thickness of wall 16 of the fixing bushes 7 made of plastic material as well as the height of the relief featured by the peripheral bead 11 as compared to the outside wall 13 of the tubular element 2 will be determined by the size of the stirrup.

The sealing stirrup as well as its fixing method as described above have the advantage of providing a very reliable fixation for the aforesaid stirrup even in the event where it is fixed in dry concrete.

In addition, fixing the stirrup in a concrete wall being cast is made easier as we only have to push the ends 9 and 10 of the stirrup fitted with their fixing bushes into the soft concrete up to the shoulder 8 of the aforesaid bushes.

Pull-out tests carried out with the sealing stirrup as described above have shown that a force of 700 kg was required to pull out the stirrup which is significantly better than the minimum specified standard level.

Furthermore, the possibility of sinking the stirrups directly into soft concrete allows for avoiding any problems regarding tightness or cracking of the walls fitted in this manner as the fresh concrete will easily penetrate between the various ribs 17 of the fixing bushes 7 and the sealing stirrup will thus become a perfectly integrated part of the wall.

Claims

1. Tubular stirrup designed to be fixed in the wall of a concrete structure and that consists of a U-shaped tubular elem'ent (2) made, in particular, of metal, and of two or of several fixing bushes (7) fitted to the ends (9,10) of the tubular element (2), stirrup characterized in that the U-shaped tubular element (2) has at its ends (9, 10) a peripheral bead (11) in the shape of a step obtained by chasing the aforesaid ends (9,10) and co-operating with the inside wall (12) of each fixing bush (7).

2. Stirrup according to claim 1, characterized in that the aforesaid peripheral bead (11) has the shape of a peripheral step in relief as compared to the outside wall (13) of the tubular element (2) and recessed as compared to the ends (9,10) of the legs (3,4) of the aforesaid tubular element (2).

3. Stirrup according to claim 1, character- ized in that the bushes (7) feature at their opening (14) a peripheral guide clearance (15).

4. Fixing method for the tubular stirrup according to any of the claims above, characterized in that the ends (9,10) of the legs (3,4) of the tubular element (2) provided with a peripheral bead 11 in the shape of a step and obtained by chasing, are slipped into the fixing bushes (7) and then these ends (9,10) fitted with fixing bushes (7) are sunk into the soft concrete up the shoulder (8) of the aforesaid 1 3 GB2183767A 3 bushes.

5. A sealing stirrup, substantially as herein described with reference to, and as shown in, the accompanying drawings.

Printed for Her Majesty's Stationery Office by Burgess & Son (Abingdon) Ltd, Dd 8991685, 1987. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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