JPH08333842A - Fixing device for end section of tension member made of steel and assembling method thereof - Google Patents

Abstract

PURPOSE: To unify a grip for fixing an end section firmly to a strand made of steel covered for rustproofing with a synthetic resin material. CONSTITUTION: A sleeve 15 made of steel is fitted and fixed at the front end section of a tension member 10 consisting of a plurality of single strands 11, 12 made of steel and made of steel in a fixing device for the end section of the tension member made of steel, and the internal surface of the sleeve 15 made of steel has a tapered hole section 18, that is the expanded front end side of the tension member made of steel. The end section of the tension member 10 made of steel is expanded along the taper of the tapered hole section 18 in the tapered hole section 18. Wedges 20 made of steel are interposed among the expanded single strands 11, 12, and a cap 23 for preventing the slip-off of the wedges is fixed at the end section of the sleeve 15 made of steel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable for suspending stress in a prestressed concrete structure or for suspending a bridge,
Further, the present invention relates to a steel tension member end fixing device used for a steel tension member for tensioning a soil retaining plate and an assembling method thereof.

[0002]

2. Description of the Related Art Conventionally, PC strands, which are steel tensile members, have been used for prestressed concrete structures, and wedge fixing has been widely used as an end fixing method. This is a fixing member 1 having a tapered hole portion 2 as shown in FIG.
Fixing wedge 4 in which a taper cylinder is divided into half so as to grasp the outer circumference of the PC strand 3 inserted in the tapered hole portion 2, and the blade-shaped ridge 5 is integrally formed on the inner surface of the wedge 4. The fixing wedge 4 is pulled into the tapered hole portion 2 by the returning force when the PC strand 3 is tensioned, and the PC strand 3 is fixed by the radial gripping force of the fixing wedge 4 at that time. Is.

In addition to this, there is a fixing method using a pressure-bonding grip. As shown in FIG. 11, a metal sleeve 6 is covered on the outside of the end of the PC strand 3, and the outer circumference is subjected to cold working to reduce the diameter. This is a method of crimping to form a pressure-bonding grip, which prevents the fixing member 1 from coming off, or a nut 7 as shown in FIG.

In recent years, a decrease in proof stress due to corrosion of PC strands with time has become a problem, and as a means for preventing such corrosion, a rust preventive material a made of synthetic resin as shown in FIGS. Corrosion-proof coated PC
Strands 8 and 9 have come to be used.

Further, the fixing using the above-mentioned pressure-sensitive grip is used not only for PC strands, but also for steel strands used for pulling earth retaining plates.

[0006]

The conventional fixing method using the pressure-bonding grip described above is such that when the grip is pressure-bonded to a steel tensile member coated with a rust preventive material made of a synthetic resin, the rust preventive material is provided in the middle. There is a problem in that the layers are interposed, which causes slippage and sufficient pressure bonding cannot be obtained.

For this reason, conventionally, the wedge fixing method had to be used, but in the conventional wedge fixing, the returning force after tensioning the PC steel material pulls it into the fixing wedge taper hole portion, and thereby the gripping force is obtained. However, in order to bite the fixing wedge by the return force, it is necessary to bite the fixing wedge and the PC steel material in advance to a certain degree or more so as not to slide in the axial direction.

However, since the anticorrosive coating layer made of synthetic resin material is present on the surface of the steel tensile member, the blade-shaped ridges of the fixing wedge are not sufficiently bitten, and the composite wire is formed between the single wires. When the resin material is present, it is compressed during fixing and the entire diameter is reduced, the return margin increases, and in some cases, a sufficient fixing state cannot be obtained.

The present invention contemplates these conventional problems,
In particular, the present invention has been made for the purpose of providing a steel tensile member end fixing device in which a grip for fixing an end is firmly integrated with a steel strand rust-proofed by a synthetic resin material.

[0010]

The features of the apparatus of the present invention for solving the above-mentioned conventional problems and for achieving the intended purpose are that a steel tensile member formed by twisting a plurality of steel single wires together. In an end fixing device for a steel tensile member, in which a steel sleeve is fitted and fixed to the distal end of the In the hole, the steel tensile member end is expanded along the taper, and a steel wedge is interposed between the expanded single strands,
In addition, a cap for preventing the wedge from slipping out is fixed to the end portion of the steel sleeve.

Further, the method of the present invention is characterized in that the tip of a steel tensile member composed of a plurality of steel single wires is passed through a steel sleeve having a taper hole portion on the tip side, and outside the taper hole portion. Expand between the tips of each steel single wire that constitutes the steel tensile member, insert a steel wedge molded into the expanded portion at approximately the same inclination as the inner surface of the tapered hole, and then The expanded tip is fitted into the tapered hole together with the steel wedge, and the cap is fixed to the outside of the tapered hole of the steel sleeve.

In the apparatus and method of the present invention, the steel tensile member is formed by twisting a plurality of side wires, which are also single wires, in a single or multiple arrangement around the core wire, which is a single wire. The metal wedge has an equal diameter hole in the center,
The outer peripheral surface is a plurality of divided cylindrical bodies,
The steel wedge may be interposed between the core wire and the side wire, and further, the steel tension member is formed by twisting a plurality of single wires in a concentric arrangement, and the steel wedge has a solid outer peripheral surface. Is formed in a taper shape, and the steel wedge may be interposed in the central portion between each single wire, and further, the steel tension member does not twist a plurality of steel single wires. It may be arranged in parallel.
Further, a male thread for fitting a fixing nut may be formed on the outer circumference of the steel sleeve, and the steel wedge is provided with a blade-shaped ridge on the surface in contact with each single wire, and a steel tensile member, The steel sleeve, cap, and steel wedge may be rust-proofed with a synthetic resin coating.

[0013]

When assembling the steel tension member end fixing device of the present invention, first, the steel tension member is passed through the steel sleeve and the tip thereof is projected to the outside of the tapered hole portion. Is loosened for the length of the taper hole, and a steel wedge is inserted into the loosened interior. Then, the steel sleeve is moved to insert the end of the steel tension member in the expanded state by inserting the wedge into the tapered hole. At this time, the end portion of the steel tensile member and the rear end of the wedge are simultaneously pushed and fitted. As a result, the single wire outside the end of the expanded steel tensile member is bent along the inner surface of the tapered hole portion and is held between the wedge outer surface and the inner surface of the tapered hole portion.

The steel tension member and the wedge may be pushed in by fitting a cap on the sleeve and screwing the cap, and the rigidity of the single element wire of the steel tension member used is If the height is high, a hydraulic jack and jig may be used, and the cap may be fitted after the pushing is completed.

The steel tensile member end fixing device of the present invention assembled in this manner is a steel tensile member expanded by fixing the steel sleeve to the bearing portion and applying tension to the steel tensile member. A force in the direction of being drawn into the taper hole is applied to the end of the, but the expanded state is maintained by the wedge, and the escape is prevented.

When the steel tensile member has a structure in which the side wires are twisted around the core wire, the core wire is clamped by the wedge by inserting a taper tubular steel wedge between the core wire and the side wires. Therefore, when the tension is applied, only the core wire does not return, and the predetermined tension can be reliably applied.

[0017]

EXAMPLE An example of the present invention will be described with reference to FIGS.

In the figure, 10 is a PC strand, which is a steel tensile material coated with a rust preventive coating, and is centered around a single core wire 11 which is a single strand of PC steel wire, and six core wires are provided around the core wire 11. The side wires 12, 12 ... Consisting of single strands of the same material are spirally wound to form a bundle of strands, and the outer circumference thereof is covered, and the internal voids are formed in the same manner as in the conventional case shown in FIG. A rustproof coating made of synthetic resin is applied to fill the

Numeral 15 is a steel sleeve fixed to the outer periphery of the end portion of the strand 10 for fixing the end portion. The outer circumference of this steel sleeve is formed into a cylindrical shape, a male screw is engraved on the outer circumference, and the fixing nut 16 and the like are screwed into the sleeve.

The steel sleeve 15 is provided with a central hole 17 through which the strand 10 is inserted, and the end of the strand 10 is inserted therein. In the center hole 17,
A taper hole portion 18 is provided, the end side of which is expanded, and the strand 10 is formed such that the end side of each side wire 12 is expanded along the inner surface of the taper hole portion 18, and the core wire 11 and each side wire expanded. A steel wedge 20 is interposed between the two.

The wedge 20 is formed by dividing a cylinder into halves. The outer peripheral surface is formed into a taper shape having substantially the same angle as the tapered hole portion 18, and the inner peripheral surface is formed into the core wire 11. Is shaped into a cylindrical shape of a uniform diameter that grips the outer periphery of the. On the outer peripheral surface and the inner peripheral surface of the wedge 20, there are integrally formed blade-shaped convex strips 21, 21 ... In the circumferential direction, and the convex strips 21, 21. The wedge 20 is interposed between the two lines while being embedded in the side line 12.

A small-diameter step portion 22 is formed on the outer circumference of the tip of the steel sleeve 15. A male screw is engraved on the outer periphery of the step portion 22. A cap 23 is screwed onto the step portion 22, whereby the wedge 20 and the strand 10 are
Does not come out on the tip side.

Next, a method of mounting the steel tension member end fixing device having the above-described structure on the strand 10 will be described.

First, as shown in FIG. 3, the tip of the strand 10 is penetrated into the sleeve 15. Next, as shown in FIG. 4, a wedge 2 is formed on the outer periphery of the core wire 11 with or without a cut in the synthetic resin coating at the end so that the side wire 12 can be expanded.
0 is press-fitted, the tip of the side wire 12 is expanded, and the tail end of the wedge 20 is press-fitted until it is flush with the tip of the core wire 11.

Next, as shown in FIG. 5, a frame-shaped jig 25 is used.
The hydraulic jack 26 with the sleeve 15 retained
The push rod 27 pushes the wedge 20 and the tips of the core wire 11 and the side wires 12 to fit the end portion of the strand 10 held in the expanded state by the wedge 20 into the tapered hole portion 18.

By this operation, the flared side wire 12 of the strand 10 is pressed toward the center, the ridge 21 of the wedge 20 bites into the core wire 11 and the side wire 12, and the wires 11 and 12 extend in the axial direction. It is fixed in the sleeve 15 in a state where the shift is prevented.

After fitting in this way, the strand 10 and the sleeve 15 are removed from the jig 25, and the cap 23 is screwed onto the end of the sleeve 15. The taper hole 18 is prevented from coming out. Although not shown in the drawing, the wedge 20
After press-fitting, the end of the strand expanded into the tapered hole portion 18 may be manually inserted to a position where the strand end portion is manually inserted, and then the cap may be screwed into the tapered hole portion 18 to be fitted therein.

If necessary, the sleeve 15 and the wedge 20
After the rustproof coating of synthetic resin material is used on the entire circumferential surface of the cap 23, and after the end of the strand 10 is expanded, the peeled portion of the rustproof material is again rustproofed. By performing the above-described fitting work into the tapered hole portion 18, a completed rust-proof end fixing device can be obtained.

In addition to the above, the wedge 20 to be used is formed by forming the same number of recessed grooves 29 as the side lines 12 fit on the outer peripheral surface as shown in FIG. The side wire 12 may be fitted to this.

Further, the steel tensile member is, for example, three single wires 2
In the case of a strand 30 having no core wire such as 8 twisted together, a solid tapered steel wedge 31 is used at the center of the twisted strand 30 as shown in FIG. Similarly, the edge fixing device is configured.

Further, the steel tensile member may be a strand in which single wires are twisted together, or may be a bundle of parallel single wires without being twisted. Similarly, the structure of FIGS. 8 and 9 can be selected and adopted according to the arrangement of the strands.

In the above-mentioned embodiment, a PC steel wire is used as the single element wire. However, in addition to this, a steel material having a lower strength than the PC steel wire used as a tension material for soil retention is used. The tensile member may be a tensile member, or a multi-twisted steel tensile member in which side wires are wound around the core wire in multiple layers.

[0033]

As described above, in the steel tension member end fixing device of the present invention, the end portions of the steel tension member are expanded between the single strands,
A steel wedge was inserted into the inside to prevent the expansion from returning, and this was fitted into the taper hole part of the steel sleeve to prevent it from falling out, so that each single wire was firmly integrated in the taper hole part. Thus, the fixing can be obtained without any returning force when fixing the strand in the tension state. Further, in particular, in the case of a steel tensile member in which the side wires are twisted around the core wire, the return of the core wire, which cannot be prevented by the conventional wedge fixing, is completely prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view of an assembling process of the device of the first embodiment.

FIG. 4 is a sectional view of an assembling process of the device of the first embodiment.

FIG. 5 is a cross-sectional view of the assembly process of the device of the first embodiment.

FIG. 6 is a cross-sectional view of the second embodiment of the present invention.

FIG. 7 is a cross-sectional view of the third embodiment of the present invention.

FIG. 8 is a vertical sectional view of a fourth embodiment of the present invention.

FIG. 9 is a vertical sectional view of a fifth embodiment of the present invention.

FIG. 10 is a half sectional view showing an example of conventional fixing.

FIG. 11 is a half sectional view showing an example of a conventional pressure grip fixing.

FIG. 12 is a half sectional view showing another example of the conventional pressure grip fixing.

13 (a) and (b) are conventional rust-proof coated PCs.
It is a cut end view showing a steel material.

[Explanation of symbols]

 10 PC Strand (Steel Tensile Material) 11 Core Wire 12 Side Wire 15 Steel Sleeve 16 Fixing Nut 17 Center Hole 18 Tapered Hole 20 Steel Wedge 21 Convex Line 22 Step 23 Cap 25 Jig 26 Hydraulic Jack 27 Push Rod 28 Single Wire 29 Recessed Groove 30 Strand (Steel Tensile Material) 31 Steel Wedge

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Taguchi 4-15-35 Mita, Minato-ku, Tokyo Times Engineering Co., Ltd.

Claims (11)

[Claims] 1. A steel tension member end fixing device in which a steel sleeve is fitted and fixed to a tip end portion of a steel tension member composed of a plurality of steel single wires, the inner surface of the steel sleeve being fixed. The steel tensile member is provided with a tapered hole portion whose front end side is expanded, the steel tensile member end portion is expanded along the taper in the tapered hole portion, and the steel member is expanded between the expanded single strands. A steel tension member end fixing device characterized in that a wedge is interposed and a cap for preventing the wedge from slipping out is fixed to the steel sleeve end. 2. The steel tensile member is formed by twisting a plurality of side wires, which are also single strands, in a single or multiple arrangement around a core wire, which is a single strand, and the metal wedge is the center. The steel according to claim 1, wherein the steel wedge is interposed between the core wire and the side wire, and is formed by dividing a plurality of cylindrical bodies each having an equal diameter hole in the outer peripheral surface and having a tapered outer peripheral surface. Tensile material end fixing device. 3. The steel tensile member is formed by twisting a plurality of single wires in a concentric arrangement, and the steel wedge is solid and has a tapered outer peripheral surface. The steel tension member end fixing device according to claim 1, wherein the steel tension member end fixing device is provided so as to be interposed in a central portion between the respective single wires. 4. The steel tension member end fixing device according to claim 1, wherein the steel tension member is formed by arranging a plurality of steel single wires in parallel without twisting. 5. The steel tension member end fixing device according to claim 1, wherein the steel sleeve has a male thread for fitting a fixing nut on an outer periphery of the steel sleeve. 6. The steel tension member end fixing device according to claim 1, wherein the steel wedge is provided with a blade-shaped ridge on a surface with which each single wire contacts. 7. The steel tension member end fixing device according to claim 1, wherein the steel tension member, the steel sleeve, the cap and the steel wedge are rustproofed by a synthetic resin coating. 8. A steel tensile member composed of a plurality of steel single wires is passed through a steel sleeve having a taper hole portion on the tip side, and the steel tensile member is formed outside the taper hole portion. Expanding between the tip ends of each steel single wire that is doing, insert a steel wedge molded into the expanded portion at substantially the same inclination as the inner surface of the tapered hole, and after that, it was expanded. A method of assembling a steel tension member end fixing device, characterized in that a tip end is fitted together with a steel wedge into the tapered hole portion, and a cap is fixed outside the tapered hole portion of the steel sleeve. 9. The steel tensile member is formed by twisting a plurality of side wires, which are also single wires, in a single or multiple arrangement around a core wire, which is a single wire, and the metal wedge is the center. 9. The steel tensile member according to claim 8, wherein the steel tension member is formed by dividing a plurality of cylindrical bodies each having an equal-diameter hole and a tapered outer peripheral surface, and the steel wedge is inserted between the core wire and the side wire. Assembling method of end fixing device. 10. The steel tensile member is formed by twisting a plurality of single wires in a concentric arrangement, and the steel wedge is solid and has a tapered outer peripheral surface. The method for assembling the steel tension member end fixing device according to claim 8, wherein the steel tension member end fixing device is inserted in a central portion between the single strands. 11. The method for assembling a steel tensile member end fixing device according to claim 8, wherein the steel tensile member is formed by arranging a plurality of steel single wires in parallel without twisting.