WO1996023934A1

WO1996023934A1 - Rod material for earth anchor and method of using the same

Info

Publication number: WO1996023934A1
Application number: PCT/JP1996/000192
Authority: WO
Inventors: Junji Hosokawa; Masao Kikuchi; Akira Sumitani; Haruhito Akimoto; Shuji Shimozono; Manabu Sotooka; Nobuyuki Ozawa
Original assignee: Komatsu Ltd.; Komatsu Plastics Industry Co., Ltd.
Priority date: 1995-01-31
Filing date: 1996-01-31
Publication date: 1996-08-08
Also published as: CA2210172A1; EP0807717A1; NO973518L; NO973518D0; JPH08209692A

Abstract

A rod material for an earth anchor comprising a roughened FRP rod covered with a film or wrapped spirally with a string member, such as a tape, so that an outer surface of the tape becomes substantially flush with that of the rod. The film of string member is partially removed, and the stripped portion of the rod is intended for contact with a grout.

Description

Field damages Reinforcement material for earth anchor method and method of using the same

The present invention relates to a rebar having a fixing portion for a grout used for an earth anchor method such as a ground anchor method, a reinforced earth method, a NATM method, and the like. About the method. Technology

In recent years, instead of steel (hereinafter referred to as PC steel) as reinforcement for concrete, the use of FRP reinforcement (hereinafter referred to as FRP reinforcement), which has excellent corrosion resistance, has begun. In recent years, these FRP bars have come to be used as reinforcing bars for ground anchoring methods such as the ground anchor method.

Among the above-mentioned earth anchoring methods, the reinforcement used in the ground anchoring method is, in particular, a tip fixing part that is fixed in the ground with a grout (for example, concrete) and an anchor free part that is an intermediate part. It is composed of a long part and a anchor head fixed to a fixed frame with a nut or the like on the ground.

And, of course, in this bar, the tip anchoring part must be firmly bonded to the grout, but the anchor free length part needs to have corrosion resistance and non-adhesion to grout. .

Therefore, in the case where a steel bar made of PC steel was used, The force free length was covered with a smooth sheath. Even if FRP bars are used in place of this, there is no problem with corrosion resistance, but in order to obtain non-adhesion to the grout, the anchor free length is used in the same way as when using the above-mentioned PC steel. At present, a smooth sheath is installed.

When a smooth sheath is not used, a non-adhesive tape (vinyl tape) is wrapped around the free length of the anchor to cut it off.

As described above, in order to provide one end of the FRP streak for the earth anchor method with the adhesive to the grout and the middle part to have the non-adhesiveness to the grout as described above, Since a smooth sheath must be attached to the middle part, which is the free length of the anchor,

The structure of the FRP muscle becomes complicated. Also, due to the structure with the smooth sheath attached in this way, FRP bars for this earth anchor method had to be produced one by one at the factory.

For this reason, each FRP bar for the earth anchor method is expensive, and its length is fixed to some extent.Therefore, there is a problem that the anchor length cannot be freely determined at the construction site. Was.

In addition, if vinyl tape is wrapped around the free length of the anchor and trimming is performed, the tape must be wrapped carefully by hand one by one, which is very complicated work at the construction site. I will.

The present invention has been made in view of the above, and does not require a smooth sheath or tape for imparting non-adhesion to grout to the free length portion of the anchor, and furthermore, the tip fixing portion can be easily formed at the construction site. It is an object of the present invention to provide a reinforcing material for an earth anchor method and a method of using the reinforcing material, which can be provided with adhesiveness to grout only to the ground. Disclosure of the invention

In order to achieve the above object, a reinforcing material for an earth anchor method according to the present invention has a structure in which a rod made of FRP having an uneven surface is coated with a coating film.

Further, the reinforcing material for the earth anchor method according to the present invention is such that a cord body such as a tape is spirally wound on the surface of an FRP rod so that the surface is substantially flush with the surface of the rod. It has a configuration that involves it.

Then, in the above-mentioned reinforcing member, the coating film or the cord body is partially removed, and this portion is used as a fixing portion for grout.

According to the above configuration, the coating film or the string attached to the surface of the FRP rod is peeled off, so that this portion has irregularities, and this portion becomes a fixing portion for grout, Other parts are non-fixed parts.

In particular, when the coating film and the cord body are a material which reacts with the uncured grout to be dissolved or gelled, in a portion where these are not peeled off (non-fixed portion), these are the grout. Reacts with and melts or gels to form a gap between the muscular material and the grout corresponding to the thickness of the coating film or the string, so that the non-fixing property can be further improved. .

^ Simple theory of face Ji The invention will be better understood from the following detailed description and the accompanying drawings illustrating an embodiment of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding.

In the figure,

FIG. 1 is a perspective view showing a first embodiment of a reinforcing member according to the present invention. FIG. 2 is an explanatory diagram showing a use state of the first embodiment.

Figures 3 and 4 are explanatory diagrams each showing a sample for a pull-out test.

FIG. 5 is a side view showing a second embodiment of the reinforcement according to the present invention. FIG. 6 is an explanatory diagram showing a use state of the second embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a reinforcing member for an earth anchor method according to the present invention, and a method for manufacturing and using the same will be described in detail with reference to the drawings.

In the figure, reference numeral 1 denotes a reinforcement, and the reinforcement 1 has a structure in which an FRP rod 2 is covered with a tubular coating film 3 made of resin _c . The entire length has irregularities 4 on the surface.

When this reinforcing material 1 is used as a reinforcing material for the ground anchoring method such as the ground anchoring method, the coating film 3 at the tip end, which requires adhesive force to the grout, is coated over a desired length. Remove with ivy.

As a result, as shown in FIG. 2, the portion where the coating film 3 is peeled off becomes the leading end fixing portion 5, and the other portion becomes the anchor free length portion 6. Then, the bar 1 is cut to the required length, and the anchor free length is cut. An anchor head (not shown) is formed at the other end on the side.

Such work can be easily performed at the construction site using the earth anchor method.

Then, the reinforcing bar 1 thus obtained is inserted into the anchor hole provided in the anchor ground from the tip fixing portion 5 thereof, and then grout is injected into the anchor hole to be solidified.

At this time, the grout fills the entire anchor hole, and the reinforcing bar 1 comes into contact with the grout over the entire length of the anchor length.However, the tip fixing portion 5 from which the coating film 3 has been stripped off is bonded to the grout and ground. It is firmly fixed to the side. On the other hand, the anchor free length portion 6 covered with the coating film 3 is not bonded to the reinforcing material 1 and the grout because the coating film 3 is interposed between the grout and the grout after solidification. There is no frictional resistance against the bird. Thus, the coating film 3 acts as an alternative to the smooth sheath in the prior art.

As the material of the FRP constituting the above-mentioned reinforcing bar 1, inorganic fibers such as carbon fiber and glass fiber and organic fibers such as aramid fiber are used as reinforcing fibers. Thermosetting resins such as epoxy resin, unsaturated polyester, phenolic resin, and vinyl ester, and thermoplastic resins such as nylon and polyester are used as the box resin.

The material of the coating film 3 may be any material that can be easily peeled off from the FRP, but a material having extremely low shear strength or a material having a large elongation under low stress is particularly desirable. In addition to PVC, polyethylene, polypropylene, nylon, etc., rubber and elastomers are generally used. However, in those limited to these Absent.

Even if the material is not a material having a low shear strength as described above, the above conditions can be satisfied by reducing the wall thickness. Materials may be used. Further, as a material for coating the rod 2, a material having low frictional resistance is desirable. This includes, but is not limited to, for example, polyethylene, polypropylene, polyacetal, fluorocarbon resins, silicone resins, and the like.

Further, as the material of the coating film 3, a material that comes into contact with the grout before curing and reacts with the grout to form a dissolved or swelling gel in a content state may be used. In this case, while the grout filled in the anchor hole is hardened, the coating film 3 dissolves or swells and gels to form a gap between the rod 2 and the hardened grout. Friction resistance to grout at the long part 6 can be eliminated.

In this case, the material of the coating film 3 includes cross-linked polyacrylamide and acrylic acid. However, in consideration of the fact that concrete as an example of a material used as a grout has a high strength, a cross-linked polyvinyl alcohol having no ionic group in the material, agar, etc. , Cellulose-based, starch-based materials, etc. are desirable. Further, the material of the coating film 3 may be in the form of a non-woven fabric bonded to the rod 2 with an adhesive soluble in water in the concrete.

The coating of the coating film 3 on the rod 2 is performed by a known means such as coating of a molten material or insertion of a tube-shaped material during or after the molding of the rod 2. Will be 6233

-7-Fig. 1 and Fig. 2 show an example in which the surface of the rod 2 is formed with irregularities 4 with tape 11 and molded, and then coated with the tube-shaped coating film 3. Examples will be described.

Rod section

Reinforced fiber: carbon, Toray T700S

Matrix resin: Yuka Seal Co., Ltd., Epikop 600 System

V f: 65%

Diameter: 10 mm

Groove shape: Groove radiation 4 mm

Groove depth 0.5 mm

Groove pitch 10 mm

Coating

Material: Shin-Etsu Polymer Soft PVC Ex 5 12 B

Meat pressure: 1 mm

Two pieces of material A and B were prepared by stripping the coating film 3 over 100 mm of the tip of the bar 1 having such a configuration. Then, as shown in Fig. 3, the material A on the other hand has a mortar 15 with a diameter of 100 mm bonded only to the part where the coating film 3 has been stripped, and the other material A as shown in Fig. 4. In Material B, a mole of 16 mm in diameter was bonded to a portion of 300 mm in total length covering the part where the coating film 3 was stripped and the part connected to it, and three times for each material. Each pull-out test was performed. The results are shown in Table 1 below. The mortars 15 and 16 were Denka Bretascon T-11, manufactured by Denki Kagaku Co., and the compressive strength of the mortars 15 and 16 at the time of the test was 482 kg / cm ² . Reference 1 2 3 Average pulling load

A 3 .18 3 .0 5 3 .4 7 3 .2 3

B 3 .8 2 3 .5 4 3 .8 8 3 .7 4

Unit: tons As is apparent from the above results, the pull-out loads of both materials A and B were almost the same on average. This indicates that also in the case of document B, the bonding with the mortar 16 was performed only at the part where the coating film 3 was stripped off. It was found that the beveling was performed reliably.

In the above embodiment, an example was given in which the coating film 3 was coated on the rod 2 having irregularities on the surface, but this coating film 3 was provided in order to reduce the frictional resistance against grout. For this reason, when the surface of the rod 2 itself has a small frictional resistance to grout, the coating film 3 is not required.

FIG. 5 shows the embodiment. In this case, in order to form a spiral groove in the rod 2, the tape 11 wound at the time of molding the rod 2 is left as it is after curing. Then, the surface of the rod 2 in this state is smoothed so as to reduce the coefficient of friction of the surface.

The reinforcing material 1 thus formed is cut to a desired length, and as shown in FIG. 6, the tape 11 at the tip fixing portion 5 is peeled off to form a spiral groove 4 at this portion. Used after forming a.

In this case, tape 11 is wound around other than the above-mentioned fixing section 5. As a result, the friction resistance against the grout can be reduced.

This embodiment, that is, an example of the use of the bar 1 in which the tape 2 is used and the tape 2 is used with only the tip fixing portion 5 of the rod 2 stripped off the tape 11 will be described.

The specifications of the rod section are the same as in the above embodiment.

Two pieces of material a and b were prepared by peeling off the tape 11 from the tip 5 of the rod 2 over 10 O mm, and the same as the example where the coating film 3 was peeled off. As a result of a pull-out test, the results are shown in Table 2 below. From this point, as in the above example, both materials a and b were bonded to the mortar only at the part where the tape 11 was peeled off. You can see that it has been done.

Table 2

Unit: tons As described above, according to the present invention, the reinforcing member 1 used in the earth anchor method is configured by covering the rod 2 made of FRP having a surface with irregularities with the coating film 3. Thus, by stripping the coating film 3 over a desired length, only this portion can be used as a fixing portion for bonding to the grout, and The portion covered with the coating film 3 can be used as a non-fixed portion for grout. Therefore The structure of the reinforcement for the ground anchoring method having a fixing part and a non-fixing part with respect to the grout can be made extremely simple without the necessity of winding a smooth sheath or local tape. it can. And since the rod 2 is made of FRP, there is no need to worry about corrosiveness as a reinforcement.

In addition, the above-mentioned reinforcing material 1 is formed by spirally winding a cord body such as a tape 11 for forming concaves and convexes on the surface of the rod 2 made of FRP, and its surface is substantially the same as the surface of the rod 2. With the configuration in which the cord is wound so as to form a surface, the string can be stripped over a desired length, thereby making it a fixing portion for the grates. Therefore, it is possible to simplify the structure of the reinforcing bar 1 which requires the fixing portion and the non-fixing portion with respect to the grout.

In addition, the coating film 3 and the string are reacted with the uncured grout to be dissolved or gelled, so that the coating film 3 and the string can be used at the time of use. There is no longer any need to strip off, making it easier to use.

Moreover, the above-mentioned bar 1 can be manufactured by almost the same procedure as that of a normal FRP bar.

Then, the reinforcing material 1 according to the present invention can be used as a fixing portion for grout by removing the coating film 3 or the cord attached to the surface of the reinforcing material 1. Since it is possible, the adhesiveness to grout can be given only to the tip fixing portion at the construction site, and the construction can be performed extremely easily.

Although the present invention has been described with reference to illustrative embodiments, the disclosed embodiments do not depart from the spirit and scope of the present invention. It is obvious to those skilled in the art that various changes, omissions, and additions are possible. Therefore, the present invention should not be limited to the above embodiments, but should be understood to include the scope defined by the elements recited in the claims and their equivalents.

Claims

The scope of the claims

1. FRP rods with irregularities on the surface coated with a coating film for earth anchor construction.

2. The reinforcing material for an earth anchor method according to claim 1, wherein the coating film is made of a material having a low shear strength.

3. The reinforcing material for an earth anchor method according to claim 1, wherein the coating film is made of a material having a small frictional resistance.

4. The reinforcing material according to claim 1, wherein the film to be coated is made of a material which reacts with uncured grout to be dissolved or gelled.

5. A reinforcing material for the earth anchoring method in which a cord is spirally wound around the surface of a rod made of FRP so that the surface is substantially flush with the surface of the rod.

6. The reinforcing material for an earth anchoring method according to claim 5, wherein a surface of the rod in which the cord body is wound is smoothed.

7. The reinforcing material according to claim 5, wherein the string body is made of a material that reacts with uncured grout to be dissolved or gelled.

8. FRP rods with irregularities formed on the surface are coated with a coating film. The coating film of the earth anchor streaks is partially removed, and this portion is fixed to the grout. How to use the reinforcement for the earth anchor method.

9. Part of the string of the ground material for the earth anchoring method in which the cord is spirally wound around the surface of the FRP rod so that the surface is substantially flush with the surface of the rod. A method of using a reinforcing material for the earth anchor method, in which this part is removed as a fixing part for grout.