JP2003105718A - Transparent cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cable to be used for introducing prestress into a boxed beam of a bridge, particularly, a cable to be used as an outer cable, with a tensile material whose condition can be grasped directly with visual check. SOLUTION: The transparent cable l comprises the tensile material 11, a cylindrical sheath 12 for protecting the tensile material 11, and a grout material 2 to be filled in a space portion between the tensile material 11 and the sheath 12, the sheath 12 and the grout material 2 being transparent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable used for introducing prestress in, for example, a box girder of a bridge, and more particularly to a cable used as an outer cable.

[0002]

2. Description of the Related Art An outer cable 10 is a disadvantage of an inner cable embedded inside a concrete structure, that is,
After introducing the prestress and filling the inner space of the sheath with grout material, the grout filling condition is not grasped, cracks in the grouting material cannot be confirmed, and it is difficult to replace the cable. As shown, the concrete structure is out of the thick section.

With such an outer cable 10, the weight of the concrete box girder is reduced, the cable construction work is facilitated, and the maintenance and repair of the cable are facilitated.

As shown in FIG. 3, the structure of the outer cable 10 includes a tension member 11 made of a PC steel strand or a PC steel rod, a sheath 12 surrounding the tension member 11, a tension member 11 and a sheath. And a grout material 13 filling a space between the grout material 12 and the space 12.

It is known that the sheath 12 is made transparent so that the filling state of the grout material 13 can be visually confirmed from the outside (for example, Japanese Patent Laid-Open No. 2001-32211).
issue).

[0006]

However, by making the sheath 12 transparent, the grout 13 inside the sheath 12 is made transparent.
Although it has become easier to check the filling condition and the cracked portion, it is still impossible to directly grasp the condition such as rust or crack of the tension member 11. The grout material 13
Is a material that is densely filled in the space for rust prevention of the tension material 11, but the material is, for example, cement milk, resin-based or oil-based filler, and is opaque. . Therefore, the filling state of the grout material 13 or the degree of "crack" can be easily confirmed by the transparent sheath, but it is still confirmed until the most important tension material 11 is rusted or cracked in the prestress introduction. There is a problem that you cannot do it. The transparent cable according to the present invention has been proposed to solve such problems.

[0007]

The gist of the transparent cable according to the present invention for solving the above-mentioned problems is to provide a tension member, a tubular sheath for protecting the tension member, and a space between the tension member and the sheath. In the cable consisting of the grout material with which the space portion is filled, the sheath and the grout material are transparent.

The grout material has an acrylic modified silicone as a main component, an organic metal catalyst as a curing agent, and a compounding ratio thereof is about 5: main component: curing agent; the grout material is a polyurethane-based elastic material. This includes the equivalent of resin Shobond Erasgrout.

According to the transparent cable of the present invention, in a cable used as an outer cable in a bridge,
Not only the sheath as a protection tube is transparent, but also the grout material inside is transparent, so the tension material can be directly applied.
It becomes possible to see with the naked eye of a person. Therefore, it becomes possible to confirm the tension / erection state of the tension member or the rust generation state, which has been impossible until now, and further, the state such as cracks can be confirmed promptly.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a transparent cable according to the present invention will be described with reference to the drawings. To facilitate understanding of the invention, portions corresponding to those of the conventional example will be described with the same reference numerals as those of the conventional example.

As shown in FIG. 1, the transparent cable 1 of the present invention comprises a tension member 1 made of PC stranded wire or PC steel rod.
1, a sheath 12 that surrounds the tension material 11, and a grout material 2 that fills the space between the tension material 11 and the sheath 12.

The sheath 12 is made of a transparent resin obtained by combining any one or two or more selected from vinyl chloride, polyethylene resin, polypropylene resin, polycarbonate resin, Teflon (registered trademark) resin and the like. .

The grout material 2 is a non-shrinkable, transparent grout material. As an example, an elastic acrylic-modified silicone (Alpron VA-120, which has low viscosity and is easy to fill)
8 (trademark): manufactured by Japan-US resin Co., Ltd. or its equivalent). As a property of the grout material, its main component is a main agent and a curing agent, the main agent is acrylic modified silicone, and the curing agent is an organometallic catalyst. In appearance, the main agent and the curing agent are transparent liquids, and the weight ratio thereof is about: main agent: curing agent = 5: 1.

The viscosity (20 ° C.) of the main component is 4,
700 mPa · s, the curing agent is 10 mPa · s, and the mixture thereof is 1,500 mPa · s. Specific gravity (20 ℃)
Is 1.02 as a grout cured product. The pot life (20 ° C.) is 5 hours (100 g scale). Furthermore, the finger touch curing time (500μ) is 10 hours at 35 ° C,
It is 10 hours at 20 ° C. and 4 hours at 30 ° C.

The apron which is the grout material 2
Physical properties of VA-1208 (trademark) are as shown in Table 1 below.

[Table 1]

Another example of the grout material 2 is a polyurethane-based elastic resin such as Showbond Erasgrout (trademark) (manufactured by Showbond Construction Co., Ltd.) or its equivalent. This grout material is composed of a base material and a curing material, and the mixing ratio (weight) of the base material: the curing agent =
It is 100: 2.

The work life of this Shobond Erasgrout (trademark) is that the ambient temperature is 40 ° C. (viscosity, 6
00 at mPa · s) for 20 minutes at 30 ° C (viscosity, 1200
50 minutes at 20 ° C (viscosity 2000 mPas)
・ S) is 90 minutes. Further, each performance is as shown in Table 2.

[Table 2]

By adopting such a transparent cable 1 made of a non-shrinking and transparent grout material as an outer cable for introducing prestress in a box girder such as a bridge, the transparent sheath 12 is adopted. Combined with this, it is possible to grasp the state of filling and the filling state such as air remaining in the filling work of the grout material, and it is also possible to directly grasp the rust occurrence state or crack state of the tension material 11 with the naked eye. You can do it.

[0019]

As described above, the transparent cable according to the present invention is filled in the tension material, the tubular sheath that protects the tension material, and the space between the tension material and the sheath. In a cable made of grout material, the sheath and grout material are transparent, so the filling status of the grout material can be easily grasped, and the inspection and repair of rust and cracks of the tension material can be done easily. It has an excellent effect of becoming.

In the grout material, the main agent is acrylic modified silicone, the curing agent is an organometallic catalyst, and the compounding ratio is about 5: main agent: curing agent = 5: 1, or the grout material is polyurethane-based. Since it is an elastic resin equivalent to Shobond Erasgrout, it has an excellent effect that the tension member can be easily confirmed directly from the outside with the naked eye.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a transparent cable according to the present invention.

FIG. 2 is an explanatory diagram showing a usage example of an outer cable using a cable according to a conventional example.

FIG. 3 is a sectional view of a cable according to the conventional example.

[Explanation of symbols]

1 transparent cable, 2 grout material, 10
Outer cable, 11 tendons, 12 sheaths.

Claims (3)

[Claims] 1. A cable comprising a tension material, a tubular sheath that protects the tension material, and a grout material that fills a space between the tension material and the sheath, wherein the sheath and the grout material are A transparent cable characterized by being transparent. 2. The grout material is characterized in that the main agent is an acrylic modified silicone, the curing agent is an organometallic catalyst, and the compounding ratio thereof is about 5: main agent: curing agent = 5: 1. The transparent cable described. 3. The transparent cable according to claim 1, wherein the grout material is a polyurethane elastic resin equivalent to Showbond (registered trademark) Erasgrout.