WO2012168549A1

WO2012168549A1 - Wire loop

Info

Publication number: WO2012168549A1
Application number: PCT/FI2012/050539
Authority: WO
Inventors: Antti Repo
Original assignee: R-Group Finland Oy
Priority date: 2011-06-09
Filing date: 2012-05-31
Publication date: 2012-12-13
Also published as: FI20115568A0; FI20115568L; EP2718509A1; EP2718509A4

Abstract

The invention relates to a wire loop (2) placed in a wire loop box (1). According to the invention, the material of the wire loop (2) is high-tensile steel wire, which material is so rigid that the wire loop stays after bending at the chosen angle in relation to the box.

Description

WIRE LOOP

The invention relates to a wire loop of a wire loop box to be used in groutable seams between wall and other prefabricated reinforced concrete elements.

Wire loop boxes are used at building sites in groutable seams between wall and other elements made of reinforced concrete. The wire loop boxes and wire loops in them create a concrete dowelling and loop reinforcement in the construction joints of concrete elements supporting the structure and increasing the strength of the seam. Within the wire loop box is located the wire loop and, when using the wire loop box, the wire loop is picked out and bent by hand to its correct position. In its correct position, the wire loop is at the angle of about 90° in relation to the box.

Recently, a problem when using the wire loop is the fact that the wire loop can after the installation and/or during grouting deflect from its correct position, whereby the connection is not as good as it could be. An object of the invention is to introduce a wire loop which eliminates disadvantages related to prior-art wire loops. A particular object of the invention is to introduce a wire loop which stays as bent in its position after bending and during grouting.

The object of the invention is achieved with a wire loop which is characterised by what is presented in the claims.

The material of the wire loop according to the invention is high-tensile steel wire, which material is so rigid that the wire loop stays after bending at the chosen angle in relation to the box. Then, the wire loop cannot move or deflect during grouting and stays well in place, which results in a good connection. There is no official definition for high-tensile steel, but it commonly refers to steel grades which are more durable than conventionally used steels. In this context, high-tensile steel refers to steel grades the yield strength of which is more than 460 MPa, and advantageously less than 700 MPa, but in some applications the yield strength can be over 700 MPa. In an advantageous embodiment of the invention, the wire loop is manufactured of wire splice including several splices and at least 6 splices. The splices and the material provide the required rigidity. The invention will now be described in more detail with reference to the accompanying drawings in which

Fig. 1 shows a wire loop box and a wire loop positioned in it, and

Fig. 2 shows an oblique side view of a wire loop according to the invention. A wire loop box 1 according to Fig. 1 includes inside of it between edges 7 a space in which is placed during storage and transport a loop 3 of a wire loop, which is designated by dashed lines in the figure. A top cover includes holes 6 through which the ends of the wire loop are led out of the space of the wire loop box. During transport and storage, there is a dust cover or a tape on top of the wire loop box. The detaching/removing of the cover takes place at the factory or the building site just before installing the wire loop box in place. After the detachment, it is possible to pull the wire loop being in the space in a desired direction, e.g. into a position shown in Fig. 1, where it is at the angle of 90° in relation to the box and thus ready for its use. Fig. 2 shows a wire loop 2, which includes a loop 3, and its free ends 4 are attached to each other by a pressable sleeve 5. The pressable sleeve is pressed around the wire loop without damaging the wire.

In this embodiment, the wire loop is 7x7 spliced steel wire having the diameter of about 8 mm. The wire is of high-tensile steel wire SE-Zn, which is a wire according to standard SFS-EN 12385 having the minimum breaking load of 40.7 kN.

Other embodiments can also employ steel wires of other kinds, suitable for the purpose. The wire diameter can be different, e.g. 6-9 mm, and its minimum breaking load can be different. For instance, the minimum breaking load of a 6- mm wire is about 23 kN.

Wire loops according to the invention are installed in the following way:

There are different sizes of wire loop boxes and wires depending on the intended use. The required wire loop is selected based on the seam width used. The required concrete strength and the division of wire loops are determined based on the shear force given in the structural designs. The wire loop boxes are installed in a mould e.g. by driving nails through the holes in the box. The bendable steel wire is installed between the reinforcements of the element. There is no need to anchor the wire to the reinforcement.

Before installing elements at the building site, the detachable covers are removed from the boxes and the wire loops are bent out of the boxes. The wire loop is turned outwards without tools or by a tool. The wire loop boxes are normally positioned in the element symmetrically in relation to the seam (horizontal direction). When the elements have been installed, a seam reinforcement bar is placed through all of the wire loops. Then, the grouting of the seam is performed with grouting concrete according to the structural designs.

The wire loop boxes create a concrete dowelling and loop reinforcement in the construction joints of concrete elements. The wire loops are installed in the element with a division determined by the structural engineer.

The invention is not limited to the described advantageous embodiments, but it can vary within the scope of the inventive idea presented in the claims.

Claims

27 Jun2012 4 CLAIMS

1. A wire loop (2) placed at least partially in a wire loop box (1), c h a r a c t e r i s e d in that the material of the wire loop (2) is high- tensile steel wire, which material is so rigid that the wire loop stays after bending at the chosen angle in relation to the box.

2. A wire loop according to claim 1, c h a r a c t e r i s e d in that the wire loop (3) is manufactured of wire splice including several splices and at least 6 splices.