JP2984879B2 - Method for forming terminal fixing part of composite cable using high strength low elongation fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates mainly to PCs using high-strength low-elongation fibers such as carbon fibers, aramid fibers and glass fibers.
The present invention relates to a method for forming a terminal fixing portion of a composite cable used for (prestressed concrete).

[0002]

2. Description of the Related Art Cables using high-strength and low-elongation fibers such as carbon fibers and aramid fibers are non-magnetic and lighter than PC steels made of high carbon steels conventionally used for PC materials. It has excellent features such as good corrosion resistance and the same strength as PC steel. However,
The cable has a structure in which a thermosetting resin is impregnated into a very thin high-strength low elongation fiber of several microns to several tens of microns, and tens to hundreds of thousands of converged fibers are thermally cured. For this reason, it is difficult to withstand a strong pressure due to a weak shear force, and if it is fixed as it is in tension, it causes early fracture. Therefore, tension and fixing, which are indispensable as PC materials, are not easy as compared with general PC steel materials.

One method for solving this problem is to impregnate an ethoxy resin or the like into a cable having a length of at least 10 times the diameter of a cable, dry it with a drier to form a buffer layer, and fix it with a predetermined wedge-type fixing device. A known method is known (Japanese Patent Publication No. 3-31832). This method can be said to be an appropriate method in which the shearing force acting on the cable is less likely to be applied to the carbon fiber of the core, but the length of the buffer layer is 10 times or more (12.8 times in the embodiment) the cable diameter. Yes, requires a fairly long buffer layer. Further, the diameter becomes large, and a fixing tool for a cable diameter of 12.5 mm and a diameter of 21.8 mm is required. Therefore, the fixing unit requires a large space,
There are problems such as difficulty in arranging in a narrow space.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem of terminal fixing of a composite cable using a high-strength low-elongation fiber. It is an object of the present invention to provide a composite cable capable of obtaining a compact and tough fixing portion having a small outer diameter, and a method of forming a terminal fixing portion capable of easily and reliably forming a fixing portion of the composite cable.

[0005]

The above object is achieved by the present invention.
Terminal fixing part of the composite cable using the low- stretch fiber, around the end of the stranded wire twisted high-strength low- stretch fiber ,
By pressurizing with heating high-strength low-elongation fiber with a thermosetting resin impregnated into the sheet-like prepreg material after wound a predetermined thickness that were formed fixing part having more lines and buffer layer integral What is achieved by a configuration characterized by
Was completed. As the prepreg material, a flexible sheet-like UD prepreg material containing carbon fiber (Uni-Di prepreg material) is used.
rectionPrepreg) is preferred.

[0006]

[Function] A cable-shaped prepreg material impregnated with a high-strength, low-elongation fiber and a thermosetting resin is wound around a terminal portion of a cable using the high-strength, low-elongation fiber, and heated while being pressurized. The prepreg material is completely integrated with the prepreg material, so that a tough buffer layer having a short length of less than 8 to 10 times the diameter of the cable and having a relatively small thickness is obtained. This alleviates the direct shearing force acting on the cable body, thereby preventing early breakage of the cable and ensuring reliable fixing. In addition, a stable shape and dimensions can be obtained because the mounting is performed by a dedicated machine having a heating and pressing mechanism as compared with the conventional method. It is also effective when a large number of strands are arranged in a narrow place as in the case of PC steel, and is convenient for use.

As described above, a fixing portion having a buffer layer made of UD prepreg is formed at the terminal portion of the stranded wire,
In a sufficiently hardened state, a fixing device for a PC steel strand was attached and tension was applied. As a result, the cable was broken at the cable main body, which proves that the strength of the cable can be sufficiently exerted.
00%), without slipping out of the strand body and slipping of the wedges, and it was confirmed that sufficient fixing efficiency was obtained. Also, in the tensile fatigue test, it was able to withstand more than 2,000,000 times of fatigue at 0.4 × tensile strength + 30 kgf / mm ² or more, and did not break.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.
As the PC material, stranded wire 4 such as 12.5 mm to 37 stranded wires and 30 mm stranded wires using PAN-based or pitch-based carbon fibers or high-strength low-elongation fibers made of glass fibers was used. Then, as a sheet-shaped prepreg material impregnated with a thermosetting resin, a flexible sheet-shaped UD prepreg material 5 having carbon fiber as a base material was employed. The sheet-shaped UD prepreg material was integrally attached to the stranded terminal portion by a dedicated cable terminal processing device developed for the purpose as follows to form a fixing portion. The UD prepreg material is composed of hundreds of thousands of carbon fibers arranged in one direction. The UD prepreg material is made to be parallel to the stranded wire 4 in the axial direction so that the length is less than 10 times the diameter of the cable and a predetermined length. Cut to a width corresponding to the winding thickness, and as shown in FIG.
Several times around the terminal. Next, as shown in FIG. 3, the end portion of the cable is set by the two circular molds 11 and 12 held in a mold holder 10 having a predetermined shape of the cable end processing device, and a predetermined load is applied by pressing once. And heat-treated for a predetermined time. At this time, the wrapped U
It is preferable to wind a polyethylene tape on the D prepreg material or apply a release agent. In this manner, the UD prepreg is completely integrated with the stranded wire end by wrapping the prepreg material around the end of the wire and subjecting the wire to pressurizing and heating treatment, and has a tough buffer layer 3 made of UD prepreg. The part 2 can be formed, and the desired composite cable 1 is obtained. Then, in a state where the buffer layer 3 is sufficiently cured, as shown in FIG. As the fixing device, an appropriate device such as a wedge-type fixing device composed of a combination of a male cone 7 and a female cone 8, which is a fixing device for a normal PC steel strand, can be adopted.

In order to confirm the effect of the present invention, a carbon fiber (PAN-based / pitch-based) and glass fiber seven-stranded wire 1
For each of the experimental examples, the UD prepreg material having a thickness of 0.35 mm was wound a predetermined number of times and the length and diameter of the buffer layer were changed for 2.5 mm to 37 stranded wires 30 mm and the like. After heating and pressurizing, and after the curing treatment, a fixing device was attached and a tensile test was performed. Further, as a comparative example, a tensile test was performed in a state where the fixing device was directly attached to the stranded wire without providing the buffer layer. Heating condition: 145 ° C, 45 minutes Pressing condition: 6300kg Fixing device: 15.2mm wedge type fixing device for PC steel stranded wire

Example 1 Test cable: 7 stranded wires 12.5 mm (carbon fiber-PA
Table 1 shows the results.

[Table 1] As shown in Table 1, when the length of the buffer layer is 100 mm or more and the diameter of the buffer layer is 15.2 mm or more, breakage occurs at the stranded wire between the fixing portions, and when the length is 14.5 mm or less, the edge of the fixing tool has high strength. It broke early due to contact with low elongation fiber. Therefore, in this experimental example, it is understood that the buffer layer is complete when the diameter of the buffer layer is 15.2 mm or more and 16.5 mm. The length of the buffer layer is
Although it may be 100 mm, the predetermined position of the fixing unit may be shifted if the length for the PC is not large enough, so that 120 mm is desirable when the length is 7 or more.

Experimental Example 2 Cable to be tested: 37 stranded wire 30.0 mm (carbon fiber-pitch type) The 37 stranded wire has a three-layer structure, so it is not sufficient to simply process the prepreg as it is. When a tensile test is performed, a phenomenon occurs in which the inner layer wire comes off. For this reason, in this experimental example, a room temperature-curable resin was previously attached to the inner and outer layers, dried, and then subjected to prepreg processing. Table 2 shows the results.

[Table 2]

Experimental Example 3 Test cable: 19 stranded wires 25.0 mm (glass fiber) The results are shown in Table 3.

[Table 3] As is apparent from the above experimental examples, according to the composite cable of the present invention, a fixing efficiency of 100% is achieved with a short length of 10 times or less the cable diameter and a relatively thin buffer layer thickness. It was confirmed that the fixing can be reliably performed with a simple fixing body.

[0013]

According to the present invention, the cable body and the buffer layer are completely integrated, and a short, less than 10 times the diameter of the cable, and a relatively thin and tough buffer layer can be obtained. Is not in contact with the cable body, and a compact fixing body having a sufficient fixing efficiency can be obtained. Therefore, it is effective also when arranging many stranded wires in a narrow place, and the work is easy. Further, since the fixing unit having the buffer layer can be formed by a dedicated machine as compared with the conventional method, a buffer layer having a stable shape and dimensions can be obtained. Further, since the fixing tool is designed so that the dimension one size larger than that of the PC steel strand can be used, it can be shared with the PC steel strand.

[Brief description of the drawings]

FIG. 1 is a perspective view of a composite cable using the high-strength low-elongation fiber of the present invention.

FIG. 2 is a perspective view showing a method of forming a terminal fixing portion of the composite cable of the present invention, in a state where a prepreg is wound around a twisted wire terminal portion.

FIG. 3 is a front view of the processing die apparatus in a state where a terminal fixing portion of the composite cable is formed.

FIG. 4 is a sectional view illustrating a fixing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Composite cable 2 Fixing part 3 Buffer layer 4 Stranded wire 5 UD prepreg 6 Fixing tool 10 Mold holder 11, 12 Mold

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Nagata 1-17-11 Kodai, Miyamae-ku, Kawasaki-shi, Kanagawa 103-72 Kadine Saginuma (72) Inventor Kaji Endo 7-5-1, Higashi-Narashino, Narashino-shi, Chiba Suzuki Metal Inside Industrial Co., Ltd. (72) Inventor Atsushi Morii 7-5-1, Higashi Narashino, Narashino City, Chiba Prefecture Inside Suzuki Metal Industry Co., Ltd. (56) References Real Opening Sho 63-50898 (JP, U) (58) Fields surveyed (Int.Cl. ⁶ , DB name) D07B 9/00 D07B 5/06

Claims (2)

(57) [Claims] 1. A sheet-shaped prepreg material having a high-strength low-extension fiber impregnated with a thermosetting resin is wound around a terminal wire of a twisted wire formed by twisting a high-strength low-extension fiber with a predetermined thickness. A method for forming a terminal fixing portion of a composite cable using a high-strength low-elongation fiber, wherein a fixing portion having a buffer layer integrated with the stranded wire is formed by applying pressure while heating. 2. The prepreg material is a flexible UD prepreg material containing carbon fibers (Uni-Direction Prep).
terminal fixing portion forming method of a composite cable using the high-strength low-elongation fibers of claim 1, characterized in that the reg).