JPH0438354A - Stretching method for frp rod - Google Patents

Abstract

PURPOSE:To improve efficiency and reliability by a method wherein the end part of an FRP rd is embedded in a curable composition, a block body formed by curing the composition is secured to the end part of the rod, and the block body forms an anchoring end for stretching. CONSTITUTION:Embedding post tension is introduced in a concrete material, and the end parts on both sides of an FRP rod 1 wherein aramide fibers serve as a reinforcing material and epoxy resin is a base material are inserted through a through-hole 3 in a temple bell-shaped casing 2. The casing 2 is then filled with cement mortar 4 to embed the end part of the rod therein, and block bodies 5 formed by curing cement mortar 4 with which the casing 2 is filled are previously secured to the respective end parts on both sides of the rod 1. Thus, the end parts of a number of the FRP rods can be secured by means of the relatively large block bodies, and a reaction force to a stretch can be supported by means of the anchoring surface of the large block body.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to FRP used for reinforcing concrete materials.
(Made of fiber-reinforced synthetic resin) Concerning the method of tensioning lots.

[Problem to be solved by the invention]

FRP rods made of aromatic polyamide fibers (aramid fibers), carbon fibers, glass fibers, etc. as reinforcement materials and epoxy resins, unsaturated polyester resins, etc. as base materials have high tensile strength and tensile modulus, and are resistant to corrosive environments. Due to its excellent durability, it is attracting attention for its use as a reinforcing material for concrete, especially as a tension material.

However, in order to use the FRP rod under tension, it is necessary to fix the end of the rod, but it is not possible to attach a fixing device like a rope using means such as a rope. For this purpose, conventionally, for example, the fixing tool was attached by inserting it into a cylindrical fixing tool having a truncated cone-shaped space and holding the FRP rod between a plurality of divided ten-shaped cones. Alternatively, a Q-FRP rod is inserted into a cylindrical fixing device, and the fixing device is filled with a synthetic resin or the like and fixed, thereby attaching the fixing device. However, the means for clamping and gripping between wedge-shaped cones has low efficiency relative to the lot strength, and the means for fixing with synthetic resin has poor reliability in the long term.

[Means to solve the problem]

This invention was made by focusing on the above problems,
The gist is that the end of an FRP rod that reinforces the concrete material is embedded in a curable composition, a block body made of the hardened composition is fixed to the end of the rod, and this block body is used as an anchoring end to apply tension. The method of tensioning an FRP rod is characterized by the following.

〔Example〕

FIG. 1 shows an FRP rod 1 that uses aramid fiber as a reinforcing material and epoxy resin as a base material, which introduces an embedded boss tension into a concrete material. Prior to embedding this rod 1 into concrete material, both ends of the rod 1 are inserted into a bell-shaped steel casing 2 through a through hole 3 at the top, and the casing 2 is filled with cement mortar 4. A block body 5 made by hardening cement mortar 4 filled in advance in the ends 2 of the rod 1 is fixed. In addition, in this example, FRP
A sheath 6 is placed over the outer periphery of the rod 1 between the block bodies 5, 5, and a thread 7 is cut on the outer periphery of the casing 2 for screwing a fixing tool or tensioning jig.

As shown in Fig. 2, this FRP rod l is buried in the concrete frame material 8 to be reinforced, and the bronc body 5 at both ends thereof is
, 5 end portions are positioned within the recessed portion 9 provided on the surface of the concrete material 8. After the concrete material 8 hardens or before burying, a ring-shaped fixing tool 10 is screwed onto the screw thread 7 on the outer periphery of the casing 2 of the block body 5.

A jack was inserted between one of the screwed fixing tools 10 and the bottom surface of the concave portion 9, or a traction device or the like was hooked and pulled, and tension was applied to the FRP lower rod 1 using the other block body 5 as a reaction force point. In this state, the gap created between the outer peripheral surface of the block body 5 and the concrete material 8 surface is filled with grout 11,
Alternatively, rotate and tighten the screwed fixing tool 10,
It was brought into pressure contact with the bottom surface, and the block body 5.5 was used as the fixing end, and a boss tension was introduced.

In the embodiment shown in FIG. 3, the ends of the FRP openings and doors 1 are embedded in cement mortar in which reinforcing bars or reinforcing bars 12 of FRP lots are arranged in the hoop direction, and block bodies 5', 5' each having a circular cross section are embedded. This is an FRP rod 1 with a 100% solid wood fixed to both ends. This rod 1 is also buried in the concrete material, for example, a jack is inserted between one block body 5' and the concrete material, and the other block body 5° is used as a reaction force point to FR.
Apply tension to P rod 1, and two block bodies 5°, 5°
The fixing end and no boss tension can be introduced.

In addition, the above-mentioned FRP rod l shown in FIG.
Insert the FRP into the inside and insert it through the through hole 3 at the bottom of the nousing.
Tension can be introduced by pulling out the rod 1 and using the block body 5' fitted in the steel housing 2' as a fixed end.

A thread 7 may be provided on the outer periphery of the 2° of the nozzling, and a fixing tool or a tensioning tool may be screwed thereto to introduce tension in the same manner as in the twenty-first embodiment.

The FRP rod referred to in this invention is an FRP material reinforced with carbon fiber, aramid fiber, glass fiber, etc., and its shape is a round bar, irregularly shaped bar, band shape, strand shape, etc. Use alignment.

When inserting the FRP rod end into the casing through a through hole and fixing the block body, even if multiple FRP rods are inserted through one through hole, or the number of FRP rods corresponding to the number of FRP rods is It may also be inserted through a through hole. The cross-sectional shape of the through hole can be freely selected, such as circular or matching the cross-sectional shape of the FRP opening/two-hole. The shape of the steel casing may be bell-shaped, or the top surface may be flat. For example, a relatively large through hole is provided on the top surface of this flat surface, and a plate with a hole suitable for inserting a separate FRP port 7 is set on top of the inside surface of the top, and the end of the FRP rod is set. It is also possible to insert it and fix the block body inside it.

In addition, by making the cross-sectional dimension of the block body smaller than the cross-sectional inner diameter dimension of the sheath 6, after the concrete frame 8 has hardened, the FRP rod can be inserted into the sheath and reinforced at a predetermined position.

The curable composition in this invention includes cement paste, cement mortar, synthetic resin paste (for example, epoxy resin paste composition), resin mortar mixed with synthetic resin, etc. Select according to the purpose of use, etc.

[Action and effect of the invention]

In this method of tensioning an FRP rod, the end of the rod is embedded in a curable composition such as cement paste, cement mortar, resin mortar mixed with synthetic resin, or synthetic resin paste, and a block body serving as a fixing end is fixed. Therefore, compared to the case of using a conventional fixing device, the ends of a large number of FRP rods can be fixed with a relatively large block body, and the reaction force of tension can be supported on the fixing surface of the large block body. In addition, by using a curable composition that has adhesion to the FRP rod, weather resistance, durability, and strength, and ensuring a sufficient length of embedding of the FRP rod, sufficient adhesion strength and durability are imparted. be able to.

Therefore, according to this FRP rod tensioning method, it is possible to efficiently apply high tension to a relatively large concrete material.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Figs. 1 and 2 respectively show an FRP rod with block bodies filled in a bell-shaped casing fixed to both ends, and this rod embedded in concrete material with boss tension. Fig. 3.4 is a cross-sectional view of the FRP rod having circular cross-sectional block bodies fixed to both ends thereof, and a cross-sectional view of the block body fitted into the housing. 1... FRP rod, 2.2゛ steel casing, 3... Through hole, 4... Cement mortar, 5.5°... Block body , 6...
Sheath, 7... Threading, 8... Concrete material, 9... Concave portion, 10... Fixture, 11... Grout , 12... Reinforcement bar.

Claims (1)

[Claims] (1) The end of the FRP rod that reinforces the concrete material is embedded in a curable composition, and a block body made by hardening the composition is fixed to the end of the rod in advance, and this block body is used as the anchoring end and tension is applied. A method for tensioning an FRP rod, which is characterized by: