JPH0726435U - Unbonded PC steel strand end structure - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents the exposure of PC stranded wire in the gap between the unbonded tube and the crimp grip. [Structure] A step having a specific height is formed at an end of the unbonded tube 18 by winding a tape 20 having a predetermined width. Then, the tape and the crimp grip 12 are connected to each other by being covered with a heat-shrinkable tube 22 that continuously covers the outer ends of the tape 20 and the crimp grip 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an end structure of an unbonded PC stranded wire in which a PC stranded wire is covered with an unbonded tube (cladding tube).

[0002]

[Prior art]

 For example, a so-called non-fixing type PC stranded wire (unbonded PC stranded wire) in which the entire length or a predetermined portion of PC steel stranded wire (also called strand or simply cable) is covered with an unbonded tube (cladding tube) made of polyethylene pipe ) Is provided as an anchor tension material used for construction of grand anchors.

In the unbonded PC steel wire, the unbonded tube is filled with a rust preventive oil such as grease to ensure expansion and contraction of the PC steel wire with respect to the unbonded tube, and at the same time, the PC steel wire strand in the unbonded tube is secured. The occurrence of rust and corrosion is prevented.

[0004]

[Problems to be solved by the device]

 Here, as an end structure of unbonded PC stranded wire, for example, a structure having a crimp grip is known. In such a terminal structure, the unbonded tube is usually cut and peeled from the terminal within a predetermined range to form a bare part of the PC steel stranded wire, and the crimp grip is bonded to the PC by crimping using a crimp jack or the like. It is fixed to the bare wire of the stranded steel wire.

By the way, since the unbonded tube is normally free from the PC steel strand, it can be moved with respect to the fixed crimp grip. In other words, when the unbonded tube moves in the direction away from the crimp grip with respect to the PC steel strand, a gap is created between the crimp grip and the unbonded tube.

[0006] In the gap between the crimp grip and the unbonded tube, the rust preventive effect due to grease or the like cannot be sufficiently obtained, so rust and corrosion caused by contact with drilling water, groundwater, etc. There is a possibility that it may occur on the PC steel strand exposed in the gap.

An object of the present invention is to provide an end structure of an unbonded PC stranded wire that prevents the exposed PC stranded wire from being exposed between the unbonded tube and the crimp grip.

[0008]

[Means for Solving the Problems]

 In order to achieve this object, according to the present invention, a step having a specific height is formed at a predetermined position on the end of the unbonded tube by winding a tape having a predetermined width. The tape and the crimping grip are connected to each other by being covered with a covering means that continuously covers the outer ends of the tape and the crimping grip.

[0009]

[Action]

 According to the present invention, the unbonded tube is reliably prevented from being detached from the covering means due to the engagement of the step portion of the unbonded tube with the tape and the covering means.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, in the end structure 10 of the unbonded PC steel stranded wire according to the present invention, the crimp grip 12 is fixed to the bare wire portion of the end of the unbonded PC steel stranded wire 14.

The unbonded PC steel stranded wire 14 is, for example, an unbonded tube (cladding pipe) 18 made of a polyethylene pipe, which is formed by twisting a plurality of wires into a whole or a predetermined portion of the PC stranded wire 16. It is formed by coating and filling the unbonded tube with rust preventive oil (not shown) such as grease.

In the unbonded PC steel wire 14 as described above, smooth expansion and contraction movement of the PC steel wire 16 with respect to the unbonded tube 18 is ensured by reducing the frictional resistance due to grease, etc. It prevents rust and corrosion caused by the intrusion of

The structure of the unbonded PC steel stranded wire 14 is well known, and the basic structure itself is not the purpose of the present invention, and will not be described in detail here.

The end treatment of the unbonded PC steel strand 14 for fixing the crimp grip 12 to the end is usually performed as follows.

As shown in FIGS. 2 and 3, first, at the end (cut end) of the unbonded PC stranded wire 14, only the unbonded tube 18 is cut and peeled off within a predetermined range from the cut end. , The bare part of the PC steel strand 16 is formed. Then, as shown in FIG. 3, a crimp grip 12 having a corresponding inner diameter is inserted and crimped into the bare wire portion of the PC steel strand 16. The crimp grip 12 is usually fixed by a dedicated crimp jack (not shown).

A general one can be used as the crimping jack, and the structure itself is not the purpose of the present invention, so it will not be described in detail here.

Here, as can be seen from FIG. 4 in addition to FIG. 1, in the present invention, a tape 20 having a predetermined width is attached to an end portion of the unbonded tube 18 at a specific height, that is, a specific thickness. The step is formed by winding until it reaches the end. Then, the covering means 22 continuously covers the stepped portion of the unbonded tube 18 and the crimping grip 12 so that the unbonded tube 18 and the crimping grip at the end of the unbonded PC steel strand 14 are connected to each other and to each other. The anti-corrosion treatment has been applied at the same time.

As the covering means 22, for example, a heat-shrinkable tube that substantially comes into close contact with the inner member due to shrinkage accompanying heating can be used. As the heat-shrinkable tube (covering means) 22, general commercially available products can be sufficiently used, and as shown in FIG. 1, the tape 20 and the crimp grip 12 are pre-cut to such a length that they are completely used. To be done.

A commercially available cloth tape, vinyl tape, or the like can be used as the tape 20, and the cloth tape or the like is wound around the surface of the unbonded tube 18 to the extent that a step can be recognized, for example, about two layers.

As can be seen from FIG. 1, in such a configuration, the heat shrinkable tube 22 wraps the tape 20 and the crimp grip 12 by heat shrinkage so that the PC steel stranded wire 16 and the unbonded tube 18 are wrapped. The heat-shrink tubing is engaged with the outer ends of both the tape step and the crimp grip, respectively, as they are in close contact with the surface of each member including. That is, according to this invention, the step of the tape 20 and the crimp grip 12 are continuously covered by the heat-shrinkable tube 22, and the outer end of the heat-shrinkable tube is engaged, so that the PC steel stranded wire for the heat-shrinkable tube is The movement and separation of the unbonded tube 18 and the crimp grip in the axial direction of 16 are surely prevented.

Therefore, even if a gap is formed between the unbonded tube 18 and the crimping grip 12, the gap is not exposed, and is separated from the PC steel under isolation from foreign matters such as drilling water and groundwater. The line 14 is reliably protected.

Since foreign matter such as drilling water and groundwater can be reliably prevented from entering from the end of the unbonded tube 18, smooth expansion and contraction of the PC steel strand at the unbonded portion is sufficiently ensured.

Here, in the embodiment, a heat-shrinkable tube is illustrated as the covering means 22, but it is sufficient if the tape 20 and the pressure-bonding grip 12 can be continuously worn, so that the heat-shrinkable tube can be used. The present invention is not limited to this, and for example, a cloth tape, a vinyl tape, or the like may be used as the covering means, and the tape and the pressure-sensitive grip may be continuously covered by taping with these.

However, if the heat-shrinkable tube is used as the covering means 22, it is sufficient if the heat-shrinkable tube preliminarily cut to a corresponding length is continuously covered on the tape 20 and the pressure-bonding grip 12 and heated. Workability and certainty of work are improved without complication.

The above-described embodiments are for explaining the present invention, and do not limit the present invention in any way, and all the modifications and alterations made within the technical scope of the present invention are also applicable. It goes without saying that it is included in the invention.

[0027]

[Effect of device]

 As described above, according to the terminal structure of the unbonded PC steel strand according to the present invention, the tape is wound around the unbonded tube to form the step portion, and the tape and the crimp grip are continuously covered by the covering means. By doing so, the movement and separation of the unbonded tube and the crimp grip in the axial direction with respect to the covering means are reliably prevented. Therefore, between the unbonded tube and the crimp grip, the PC steel wire is not exposed, and it is reliably isolated and protected from foreign matter such as drilling water and groundwater.

Since foreign matter such as drilling water and groundwater can be reliably prevented from entering from the end of the unbonded tube, smooth expansion and contraction of the PC steel strand at the unbonded portion can be sufficiently ensured.

Further, if the heat-shrinkable tube is used as the covering means, the heat-shrinkable tube preliminarily cut into a corresponding length may be continuously covered and heated on the tape and the crimp grip, which complicates the work. Therefore, workability and work reliability are surely improved.

[Brief description of drawings]

FIG. 1 is a schematic side view of an end structure of an unbonded PC steel strand according to the present invention, showing a heat shrinkable tube (coating means) in a longitudinal sectional view.

FIG. 2 is a partial perspective view of an unbonded PC stranded wire showing an initial state of a terminal.

FIG. 3 is an exploded perspective view of an unbonded PC stranded wire and a crimp grip.

FIG. 4 is an exploded perspective view of an unbonded PC stranded wire and a heat-shrinkable tube after fixing a crimp grip.

[Explanation of symbols]

 10 End structure of unbonded PC steel stranded wire 12 Crimping grip 14 Unbonded PC steel stranded wire 16 PC steel stranded wire 18 Unbonded tube (cladding tube) 20 Tape 22 Coating means (heat shrinkable tube)

Claims (2)

[Scope of utility model registration request] 1. A terminal structure of an unbonded PC stranded wire in which a crimping grip is fixed to a bare wire portion of the PC stranded wire formed by cutting and peeling an unbonded tube over a predetermined range from a terminal, and a tape having a predetermined width is used. By winding, a step having a specific height is formed at a predetermined position on the end of the unbonded tube, and at least the tape, by covering with a covering means that continuously covers the outer ends of the crimp grip, the tape, An end structure of unbonded PC steel stranded wire characterized in that the crimp grips are interconnected. 2. The terminal structure of an unbonded PC steel strand according to claim 1, wherein the covering means is a heat shrinkable tube having a length capable of integrally covering the outer ends of the tape and the crimp grip with each other.