JPH0733662B2 - anchor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor, and more particularly to an anchor having a high corrosion resistance and a high reliability even when applied to acidic soil.

[0002]

2. Description of the Related Art In order to protect the tension material of anchors such as PC strands and to obtain a fixing force, the outer periphery of the fixing portion of the tension material is covered with a steel fixing sheath, and the inside and outside of the fixing sheath inside the drilling hole Was filled with a cement hardener. The deformed fixing sheath prevents water that has come out of the acidic soil from reaching the tension material, and the cement-based hardening material inside protects the tension material.

[0003]

However, in reality, the fixing sheath made of steel may be damaged during construction, resulting in a hole through which water can pass through. Further, when a tensile force is applied to the tensile material, a crack occurs in the hardened material in the fixing sheath, and water passing through this hole sometimes traces the crack and reaches the tensile material. This water may cause corrosion of the tensile material and cause the tensile material to break.
Damage to the fixing sheath that is no longer identifiable, such as damage within the drilled hole, can cause tension material to break. It has been desired to develop an anchor that prevents water from entering the inside of the sheath even if it breaks.

In order to prevent damage, it is possible to increase the thickness of the fixing sheath to make it stronger, but if it is made too thick, the weight becomes heavy and a great deal of labor is required for transportation and construction work. . Further, the fact that the thickness of the fixing sheath becomes thicker means that the diameter of the entire anchor becomes larger, and the larger the diameter, the larger the diameter of the drilled hole into which the anchor is inserted. However, even if the diameter of the drilled hole is increased by 5 mm, the construction machine becomes large-scaled and the construction time becomes long, so that the construction cost becomes significantly high.

The present invention has been made to solve the above problems, and an object thereof is to provide an anchor having a high corrosion resistance and a low construction cost.

[0006]

In the anchor according to the present invention, the deformed sheath that covers the fixed length portion of the tension member is doubled. The deformed sheath uses a stainless steel sheath, and has a thread-shaped convex portion that is continuous over the entire length. One of the deformed sheaths is on the outer side, and the deformed sheath having a diameter slightly smaller than that of the deformed sheath is made into a double layer by screwing the deformed sheaths inward with the convex portions aligned with each other. A synthetic resin is filled in the gap between the double-shaped modified sheaths. As the synthetic resin, one having high viscosity such as epoxy resin is used.

[0007]

[Effect] Even if the multiple sheaths are broken, the synthetic resin filled therein expands greatly and follows the expansion of the sheath, so that the holes formed in the sheath are blocked by the synthetic resin and the water reaches inside. Prevent.

Inside the stainless steel deformed sheath, a stainless steel deformed sheath is further doubled by screwing the convex portion, and the gap is filled with synthetic resin. Is thin, and the diameter of the entire anchor does not increase. Therefore, it is not necessary to increase the diameter of the hole to be inserted, and the construction cost can be kept low.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on an embodiment shown in the drawings. In the figure, 1 is a tensile material, and PC strands are used in the embodiment. This tensile material 1
The free length portion A is of the unbonded type and is passed through the polyethylene sheath 2. The free length portion of the plurality of tension members 1 is passed through a straight sheath 3 made of synthetic resin.

The fixed length portion of the tension member 1 is passed through the double-shaped modified sheaths 4 and 5 while being left bare. The irregular shape means that the outer shape of the sheath is bent and formed in a corrugated shape, and the convex portion is formed in a thread shape continuous over the entire length. Therefore, by combining the convex portions with each other, the sheath having a small diameter can be screwed into the inside of the outer sheath, so that the sheath can be easily multiplexed. Both of the deformed sheaths 4 and 5 are made of stainless steel, and the deformed sheath 4 having a slightly smaller diameter is screwed into the inside of one deformed sheath 5 so that the stainless steel has a high strength. It is large and a thickness of 0.5 mm or less is sufficient for the sheath, and it is extremely thin as a double sheath by making it double. In particular, since the one sheath 4 is screwed into the inside of the other sheath 5 by aligning the convex portions, the thickness of the two sheaths is almost the same as that of the single sheath.

A synthetic resin 6 is filled in the space between the double-shaped modified sheaths. In the examples, an epoxy resin is used as the synthetic resin. Epoxy resin has a high viscosity and easily follows elongation and bending of the sheath.

The space between the straight sheath 3 and the deformed sheaths 4 and 5 is partitioned by a water blocking material 7 such as blown asphalt and inserted into the drilled hole 8. Inside the sheaths 3 and 4 and drilling holes 8
The anchor is fixed by filling the gap between the and with a hardening material 9 such as cement paste.

Even if the deformed sheath 5 of the fixing portion is damaged due to an unforeseen situation during construction or due to a tensile load or the like, FIG.
As described above, since the synthetic resin 6 on the inner side has a large stretching force and stretches in accordance with the stretching, the hole formed on the outer deformed sheath 5 is closed and water is prevented from entering the inner side. Further, since the sheaths 4 and 5 are doubled, the restraining effect of the cement paste grout injected into the inner sheath 4 and the anchor tension member 1 is remarkably improved, and the test result is also obtained in which the adhesive strength is remarkably improved. As a result, the binding effect was more than doubled and the adhesion effect was immediately enhanced.

[0015]

The present invention has the above-mentioned structure and can obtain the following effects. Since the sheath that covers the fixing part of the tension material is doubled and the gap between the sheaths is filled with synthetic resin, even if the sheath breaks, the synthetic resin follows the expansion and closes the damaged part, and water invades inside. Prevent. Since the stainless steel deformed sheath is doubled by screwing one side into the other, the thickness does not become thick and the anchor diameter does not increase. Therefore, inexpensive construction is possible without increasing the diameter of the drilled hole. By using the double sheath made of stainless steel, the effect of restraining the hardened material inside the sheath is enhanced, and the adhesive force between the fixing portion of the tensile material and the hardened material is enhanced.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an anchor according to the present invention.

FIG. 2 is a partially enlarged view thereof.

FIG. 3 is an overall view of an anchor.

[Explanation of symbols]

 1 Tensile material 2 Unbonded sheath 3 Straight sheath 4/5 Deformed sheath 6 Synthetic resin 7 Water blocking material 8 Drilling hole 9 Hardening material

Claims (1)

[Claims] 1. A stainless steel deformable sheath in which a convex portion is formed around the fixed length portion of the tension member in the shape of a screw thread that is continuous over the entire length, and the other thread thread that is also continuous over the entire length is formed. -Shaped convex portion is formed, and a deformed sheath made of stainless steel with a diameter slightly smaller than that of the deformed sheath on the outside is screwed in to form a deformed sheath that is doubled. An anchor made by filling synthetic resin in the gap.