JPH06102925B2 - Fiber-reinforced synthetic resin prestressed concrete tension member anchoring structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] The present invention relates to prestressed concrete (hereinafter referred to as “PC”).
The tension member used in the structure, more specifically, the fixing part structure of the PC tension member made of fiber reinforced synthetic resin (hereinafter referred to as "FRP").

[Prior Art] In recent years, a PC tension material made of fiber reinforced synthetic resin using glass fiber or the like for a PC structure has been applied.

This is because the rod formed by molding a glass monofilament having a diameter of several microns with a thermosetting resin is used as a PC tension member, so a fixing mechanism using a conventional PC steel material, for example,
It is unreasonable to use a mechanism that engraves a screw on the end of a PC steel rod and fixes it to the concrete body via a nut that is screwed into the screw, because the fiber is cut and the stress of the tendon material decreases. .

However, various fixing mechanisms for the FRP-made PC tension material have been proposed, and one such proposal is disclosed in Japanese Patent Publication No. 52-25177. That is, as shown in FIG. 1, at the end of the FRP PC rod a, the fixing member b
And fixing them by a synthetic resin adhesive layer c over a required length, and a wedge d is driven into the end surface portion of the PC rod a to form a conical portion, and a conical hole formed at one end of the fixing body b. e has a structure in which the conical portion is adhered. Then, the prestressing force introduced into the PC rod a is transmitted to the structure h via the nut f and the washer g.

However, in the prior art, the fixation between the PC rod and the fixing body is mainly due to the synthetic resin adhesive layer, and the synthetic resin adhesive layer is weak against shearing force and cannot hold a large tension force. The end surface of the PC rod is made into a conical shape by hammering in a wedge, but since the slope of the conical portion is formed at a steep angle, stress concentration occurs, which causes damage to the PC rod. can do.

[Object of the present invention] Therefore, the present invention has been made to overcome the problems of the above-described prior art, and the mechanical and physical properties of the FRP-made PC rod are utilized while making use of the wedge action which is the feature of the prior art. It was made paying attention to the characteristics.

That is, since the FRP fibers are arranged in the same direction in the FRP PC rod, it is possible to make a crack in the axial direction relatively easily. . Then, by forming a crack from the end surface of the FRP PC rod, a gradient is formed on the outer peripheral surface of the end portion of the rod, and the wedge is selected by selecting an appropriate value for the gradient and appropriately interposing a solidifying resin. It was confirmed that the action could be enhanced.

[Configuration of the present invention]

The structure of the fixing portion of the FRP-made PC tension material of the present invention is based on the above knowledge, and specifically, the following configuration (technical means) is adopted. That is, at the end of the fiber-reinforced synthetic resin prestressed concrete tension material, the tension material is divided into cracks along the axial direction of the tension material over the length for holding the fixing length, and the spacers are inserted into the cracks. Expand the outer peripheral surface of the end of the toward the end 1/40 to 1/50
Is formed on the tapered surface of the gradual slope of
A fixing body having an inner hole corresponding to the tapered surface is fitted to an end portion of the fiber-reinforced synthetic resin prestressed concrete tension member, and a crack of the fiber-reinforced synthetic resin prestressed concrete tension member and the prestressed concrete tension member. A solidified resin is filled in a gap between the outer peripheral surface and the inner hole of the fixing body.

The FRP PC tension member fixing portion structure of the present invention is applicable to both the post-tension system and the pre-tension system.

In the above-mentioned configuration, the FRP PC tendon material is divided at its end portion to form a predetermined gradient, but there are various modes as means for forming the gradient, and one of them in the present invention. It is not limited to. Then, in order to obtain a predetermined gradient of the PC tension member, usually, a mode is adopted in which the inner hole of the fixing member is formed to have a predetermined gradient and the PC tension member is pressed against the inner hole.

In addition, the edge of the FRP PC tendon is generally graded over the anchor length, where
Is a length necessary and sufficient for continuously transmitting the prestressing force introduced into the PC tendon to the PC structure.

Normally, one PC tension material is placed in the inner hole of the fixing body,
It does not prevent you from arranging two or more PC tendons.

The materials applied to the present invention are as follows.

FRP PC tension material is impregnated with thermosetting resin such as epoxy resin containing inorganic hard fibers (glass fiber, carbon fiber, etc.) or organic long fibers (aromatic polyamide fiber: trade name "Kevlar") mixed with a hardening agent. Then, the long fibers are drawn in through a molding die while being aligned in the fiber direction and molded and cured, so-called fibers are arranged in one direction,
Axial division becomes easy.

Thermosetting resins used for FRP include epoxy resins, unsaturated polyester resins, diallyl phthalate resins and the like.

As the solidified resin filled in the inner hole of the fixing body, a synthetic resin adhesive which is cured at room temperature and has high strength is used. A polyester-based, epoxy-based, or polyurethane-based adhesive is suitable as such a solidifying resin.

[Operation and effect of the present invention]

The fixing portion structure of the FRP-made PC tension member having the above-described configuration of the present invention has the following unique effects.

Since the taper surface has a gentle slope of 1/40 to 1/50 over the fixing length, the end of the PC tension member is bent at a gentle slope and engages with the fixing body, so that stress concentration occurs in that part. Since it does not occur, there is no breakage of the FRP fiber, and the tension material can exert great strength.

Furthermore, by adopting the gradient, the wedge effect between the end portion of the PC tension member and the inner hole of the fixing member can be more effectively exhibited.

The use of spacers allows the ends of the FRP PC tendons to be precisely formed and held on a tapered surface with a given gentle slope.

The outer surface of the end of the FRP PC tension member and the inner surface of the inner hole of the fixing member form a taper engagement with a gentle gradient directly and / or through a thin layer of the solidified resin, During tension (so-called pre-stressing), stress concentration does not occur at the end, both sides, that is, the end of the PC tension material and the fixing body exert a wedge effect, and the PC tension material does not pull out from the fixing body. Not only that, the tension force is effectively transmitted from the fixing body to the PC tension member, and the prestress force is not reduced. Further, even if the PC tension member is distorted and reduced in diameter during the pre-stressing, the PC tension member and the fixing member form a taper engagement, so that they can satisfactorily follow.

The solidified resin filled in the cracks of the tension member and the gap between the outer peripheral surface of the tension member and the inner hole of the fixing member exhibits compression resistance and enhances the wedge action at the end portion of the tension member.

The solidified resin filled in the inner hole of the fixing body flows into the cracks of the PC tension material and is solidified, so that the wedge body at the end portion of the PC tension material is well retained.

The solidified resin is thinly interposed between the outer surface of the end of the PC tension member and the inner surface of the inner hole of the fixing body, so flow deformation does not occur even under high stress, and prestressing force can be maintained well. .

The wedge processing of the end of the FRP PC tension material can be easily formed by dividing the ready-made FRP rod, and no special manufacturing equipment for it is required.

[Embodiment of the Present Invention] FIGS. 2 to 5 show a single embodiment of the present invention.
The structure of the fixing part of PC tension material is shown.

Here, 1 is a rod-shaped PC tension member made of FRP (hereinafter referred to as "FRP rod").

1A is an end formed on both ends of the FRP rod 1.
The rod end portion 1A is split in a cross shape in the axial direction so that its cross section is divided into quadrants. Reference numerals 1a, 1b, 1c and 1d denote divided end pieces that are divided into quadrants of the rod end portion 1A. A spacer, which will be described later, is inserted into the crack of the rod end portion 1A to form the outer peripheral surface thereof at a required slope.

Reference numeral 2 denotes a hollow cylindrical fixing member, which is usually made of a metal material. 2A is a screw engraved over the required length of the outer circumference of the fixing body, and 2B is an inner hole penetrating the fixing body. The inner surface of the inner hole 2B is formed in a taper having a predetermined gradient (1/40 to 1/50). 2C is a vertical pin hole for holding a spacer pin described later, and 2D is a horizontal pin hole. 2E is the fixing body 2
Is a concave groove formed on the inner end surface side of the.

A vertical pin 3 for a spacer is inserted into the vertical pin hole 2C of the fixing body 2.

A horizontal pin 4 for a spacer is inserted into the horizontal pin hole 2D of the fixing body 2.

Reference numeral 5 is a solidified resin filled in the inner hole 2B of the fixing body 2.
The solidified resin 5 is filled in the crevices of the FRP rod end 1A which are spread by the spacers 3 and 4, and in the gap between the outer peripheral surface of the FRP rod end 1A and the inner surface 2B of the fixing body 2. The FRP rod end portion 1A is effectively held in shape by being solidified. An epoxy adhesive is preferably applied to the solidified resin 5.

Reference numeral 6 denotes a sealing member, which is mounted in the concave groove 2E at the end of the fixing body 2 to prevent leakage when the solidified resin 5 is filled, and
It prevents stress concentration when the FRP rod is under tension.

In this embodiment, the fixing body 2 is sufficiently long, and the end portion 1A of the FRP rod is fixed to the fixing body for a required fixing length.

Assembling of the fixing portion of the FRP rod of this embodiment is performed as follows, for example.

That is, the end 1A of the FRP rod 1 is cracked over the required length (that is, the fixing length). Prepare the fixing body 2 incorporating the pins 3 and 4, and insert the FRP into the inner hole 2B of the fixing body 2.
Push rod 1 in. At this time, FR pins 3 and 4
By pushing into the crack of the P rod 1, the outer periphery of the end 1A of the PC rod 1 is installed at a predetermined slope. In this state, the adhesive resin 5 is filled in the inner hole 2B of the fixing body 2 and waiting for its solidification to complete the assembly of the fixing portion. The above-mentioned filling of the adhesive resin 5 is performed under a predetermined pressure.

The tension force is introduced into the concrete structure by the FRP rod of this embodiment as follows (see FIG. 6).

FIG. 6 (a) shows a mode by the post tension system. That is, the FRP rod 1 cut off from the concrete structure H is inserted with the sheath I in the concrete structure H. The fixing member 2 is attached to both ends of the FRP rod 1 by the above-mentioned assembling method. The fixing body 2 may be attached to both ends of the FRP rod 1 in advance in a factory or the like. When the concrete structure H has a predetermined strength, a reaction force is applied to the concrete structure H via the washer J, and the FRP rod 1 is moved in the direction of arrow α by a tension jack (not shown) via the fixing body 2. Pull. When the required tensile force is applied, the nut K is screwed into the washer J surface and fixed. Then, when the tensile force of the jack is released, the required prestressing force is introduced into the concrete structure H via the nut K.

FIG. 6 (b) shows a mode by the pre-tension system.
That is, the fixing member 2 is attached to the end portion of the FRP rod 1 by a required method, and the screw 2A of the fixing member 2 is used to further connect the coupler M and the tension rod N connected to the tension jack (not shown). It is installed. Then, the pulling jack applies a reaction force to the reaction force member O and pulls the tension rod N, thereby introducing a pulling force to the FRP rod 1. Next, concrete is poured into the form of the concrete structure (for example, concrete sleepers) L, and the solidification of the concrete is waited. When the concrete solidifies and the adhesion between the concrete structure and the FRP rod 1 becomes sufficient, the prestress is introduced into the concrete structure L by loosening the jack. In this case, an appropriate attachment means is adopted for the FRP rod 1.

In this embodiment, the vertical pin 3 and the horizontal pin 4 are used as the spencer for holding the gap between the FRP rod end portions 1A, but the spacer is not limited to this mode, and other means can be adopted. FIG. 7 shows an example thereof. (A) shows a cross-shaped spacer 10, and one or more spacers
Insert 10 into the split and hold the split end piece of the FRP rod divided into quadrants in cross section at the required slope. (B) shows a Y-shaped spacer 11, and one or more spacers 11 are inserted into the cracks to hold the divided end pieces of the FRP rod divided into quadrants in cross section at a required slope. (C) shows a T-shaped spacer 12, and one or more spacers 12 are inserted into a crack to hold the divided end piece of the FRP rod divided into a quadrant and a bisector at a required gradient. To do.

Next, an example of a fixing part structure of a plurality of FRP PC tension members will be shown.

FIG. 8 is an end view showing the fixing structure of the ends of two FRP rods.

Here, the ends of the FRP rods 15 and 16 are divided into ternary circles in the fixing body 17, and the Y-shaped spacer is formed in the crack.
18 and 19 are inserted and pressed into the fixing body 17. Reference numeral 20 is a solidified resin filled in the fixing body 13. Since the inner surface of the fixing body 17 is formed with a predetermined gradient (1/40 to 1/50), the end portions of the FRP rods 15 and 16 are formed into a conical wedge body as a whole.

FIG. 9 shows the fixing structure of the ends of the three FRP rods.

Here, the FRP rods 30, 31, 32 are divided into three quadrants in the fixing body 33, and the Y-shaped spacers 34, 3 are formed in the cracks.
5, 36 are inserted and pressed into the fixing body 33. 37 is a solidified resin filled in the fixing body 20.

FIGS. 10 and 11 show the structure of the fixing unit at the ends of the four FRP rods.

Here, each of the FRP rods 40, 41, 42, 43 is a fixing member 4
It is divided into quadrants and bisects in 4, and the ring-shaped spacer 45 is inserted into the cracks all at once to push the divided end pieces of the quadrants placed outside to the inner surface of the fixing body 44. And form a predetermined gradient. Reference numeral 46 is a solidified resin filled in the fixing body 44, and 47 is a sealing member.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing the structure of a fixing portion of a conventional FRP PC tension member. 2 shows the embodiment of the present invention, FIG. 2 is a partial sectional three-dimensional view of one embodiment of the fixing portion structure of a single FRP PC tension member of the present invention, and FIG. 3 is an end view thereof. ,
4 is a sectional view taken along line XX of FIG. 3, and FIG. 5 is a sectional view taken along line YY of FIG. FIGS. 6 (a) and 6 (b) are explanatory views of the procedure of prestressing. FIGS. 7 (A), (B) and (C) are perspective views showing another embodiment of the spacer. Figure 8 shows two FR
An end view of another embodiment showing a fixing portion structure of a PC-made tension material made of P,
FIG. 9 is an end view of yet another embodiment showing the fixing portion structure of three FRP PC tension members, and FIG. 10 is still another embodiment showing the fixing portion structure of four FRP PC tension members. Fig. 11 is an end view of Fig.
FIG. 10 is a sectional view taken along the line ZZ in FIG. 1 ... FRP PC tension material (FRP rod), 1A ... end, 2 ...
… Fixing body, 2A …… Screw part, 2B …… Inner hole, 3,4,10,11,12…
… Spacer, 5… Filled and solidified resin

Claims (1)

[Claims] 1. A prestressed concrete tendon made of fiber reinforced synthetic resin is divided at the end thereof by a crack along the axial direction of the tendon over a length for holding a fixed length, and a spacer is inserted into the crack. The tension member is formed into a taper surface having a gentle gradient of 1/40 to 1/50 that expands the outer peripheral surface of the end portion toward the end portion, and has an inner hole corresponding to the taper surface. A fixing body is fitted to an end of the fiber-reinforced synthetic resin prestressed concrete tension material, and a crack in the fiber-reinforced synthetic resin prestressed concrete tension material and an outer peripheral surface of the prestressed concrete tension material and an inner hole of the fixing body. A fixing part structure for prestressed concrete tendons made of fiber reinforced synthetic resin, characterized in that the gap is filled with a solidifying resin.