JPH07189427A - Anchorage construction of end of frp reinforcing material - Google Patents

Abstract

PURPOSE:To prevent the delayed destruction of an FRP reinforcing material and maintain a stabilized anchoring state more than 24 hours by connecting with couplers wedge sleeves wherein wedge angles are make larger from the tops to the ends step by step. CONSTITUTION:Wedge sleeves 3a and 3b externally fitted on an FRP reinforcing material A are connected with couplers 5a internally fitting elastic bodies 6a, and wedges 4a of the wedge sleeves 3a are pushed from the rear. The wedges 4a divided into a plurality of wedges are pushed inside the wedge sleeves 3a to adhere the surface of an inside diameter to the FW reinforcing material A. When pressed concrete is manufactured, the combinations of the wedge sleeves 3a, wedges 4a and couplers 5a are connected in series, and a tensionning tension bar is connected to the endmost coupler 5a to pull. By making an angle of the wedge larger from the top to the end successively, anchoring force corresponding to tension of the FRP reinforcing material A is equally distributed to the wedges 4a, and concentrated stress generated in the front end of each of the wedges 4a is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a reinforcing material (hereinafter referred to as FR
(Referred to as “P reinforcement”).

[0002]

2. Description of the Related Art Concrete and its technical problems have the property of easily cracking. To prevent this, reinforcing bars and steel materials are embedded in the concrete to reinforce it. The prestressed concrete method is used to increase the strength. In this prestressed concrete method, a predetermined tension is applied to the reinforcing material in advance, the concrete is placed therein, and the tension of the reinforcing material is released after the concrete is trained, so that the concrete is Prestress is introduced into the concrete by the adhesive force of the reinforcing material and the tension of the reinforcing material to strengthen the concrete. Conventionally, a steel wire or a steel stranded wire has been used as a reinforcing material for this prestressed concrete, but there are problems in terms of weight, corrosion resistance and magnetism.
For this reason, FRP reinforcing materials have been developed in place of such steel-based reinforcing materials, and since such reinforcing materials are lightweight, they can improve workability of transportation and bar arrangement, and also have excellent corrosion resistance and salt damage resistance. It is suitable for structures and also suitable for non-magnetic structures because it is non-magnetic, and its application tends to be expanded.

When this FRP reinforcing material is used in prestressed concrete, it is naturally necessary to provide a terminal fixing member for giving a certain tension. As this terminal fixing structure, a wedge method adopted for a reinforcing material composed of steel wire or steel stranded wire is considered, but this method is FR
If it is applied as it is to the P-reinforcing material, the shearing phenomenon of the high-strength, low-elongation fiber will occur due to the compression action applied from the cone or sleeve, and the predetermined fixing force cannot be obtained. Various measures have been proposed as measures against this problem, and a typical example is a resin-filled socket system. This is a steel socket with FRP
Inserting the end of the reinforcing material, pouring a thermosetting resin into the gap between the inner surface of the socket and the outer surface of the FRP reinforcing material, and curing reaction of the resin to integrate the socket and the FRP reinforcing material. And has an advantage that a relatively high fixing property can be obtained by the adhesive effect. However, in this method, it takes time to prepare the thermosetting resin and control the temperature, and it usually takes about 6 hours to cure the resin, which increases the processing cost. Furthermore, since the socket is used, the outer diameter of the fixing body is increased. When the size is increased and the reinforcing bars are densely arranged on the concrete cross section, the sockets are in contact with each other and the reinforcing bar density cannot be increased so much.

Therefore, the applicant of the present invention has proposed the Japanese Patent Publication No. 3-31832.
In the publication, a method was proposed in which a cylindrical resin buffer layer was provided on the surface of the required area of the end of the FRP reinforcing material, and this was wedge-fastened. In this prior art, the resin buffer layer acts as a buffer against the pinching force of wedges, so that shear breakage of the FRP reinforcing material is prevented, and the adhesion area with the FRP reinforcing material is improved, so that the fixing load is improved. . Therefore, although fixing for a short time is considered to have some effect, there is a big problem in that stable fixing for a long time is difficult. That is, the curing time of the concrete in the prestressed concrete is usually about 12 hours to 24 hours, and during that time, it is necessary to keep the tension of the FRP reinforcing material constant. Therefore, at least during the curing period, the stable colonization of wedges must be maintained. However, the FRP reinforcing material is formed by impregnating high-strength, high-elasticity fiber with a thermosetting resin and curing the impregnated thermosetting resin to form a predetermined cross-sectional shape and a predetermined outer diameter. Therefore, although the tensile properties differ depending on the type of fiber used, the elastic modulus is approximately 4
000 to 15,000 kgf / mm ² , and in the case of steel wire or steel stranded wire, 20,000 to 21,000 kgf
Remarkably smaller than / mm ² . Therefore, when the same tension is applied to both, the FRP reinforcing material has a larger strain than the steel wire or the steel stranded wire, stress concentrates at the mouth portion of the wedge, and an excessive concentrated stress portion occurs. This is also the case in the prior art, because concentrated stress acts on the resin buffer layer located at the wedge tip for the above reason,
Under continuous tension, the stress concentration part of the resinous buffer layer is destroyed,
Due to the destruction, the stress concentration portion moves to the resinous buffer layer ahead of the mouth of the wedge, and this portion is also destroyed. Further, the destruction of the resinous buffer layer gradually spreads over the entire wedge with the passage of time. Therefore, the so-called delayed fracture phenomenon causes the resin buffer layer to be destroyed, and in the final state, the FRP reinforcing material slips out from the wedge and the fixing force is lost.

The present invention was devised to solve the above-mentioned problems, and its purpose is to provide a delay while making use of the advantages of the wedge type that can fix an arbitrary position of the reinforcing material and has good workability. An object of the present invention is to provide a terminal fixing structure of an FRP reinforcing material that can maintain a stable fixing state for 24 hours or more of concrete curing time without causing destruction.

[0006]

In order to achieve the above object, the present invention uses a plurality of wedge rows and aims at fixing by changing the wedge angles in a non-uniform manner stepwise. . That is, the present invention relates to a wedge sleeve which is covered with an FRP reinforcing material composed of a composite of high-strength and high-elasticity fibers and a thermosetting resin, a coupler connected to the rear portion of the wedge sleeve, a wedge sleeve, and a pair of the couplers. Is connected to the rear of the first fixing device provided with the FRP reinforcing material and the wedge pushed between the wedge sleeves by the elastic body disposed in the rear of the wedge sleeve having the screw for coupling the coupler, and the rear of the wedge sleeve. Coupler with a wedge sleeve and an elastic body arranged inside the coupler to make F
One or more fixing devices having an RP reinforcing member and a wedge pushed between the wedge sleeves are provided in series, and the taper angle α ₁ of the wedge and the taper angle αn of the wedge behind the wedge are provided.
Is characterized by having a relationship of α ₁ <αn. The number of subsequent fixing devices is usually 2 to 4, but it may be more than that in some cases.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show a first embodiment of a terminal fixing structure of an FRP reinforcing material according to the present invention, that is, an example in which a fixing device is a series triple connection type, and FIGS. 3 and 4 show a second embodiment of the present invention, namely An example is shown in which the fixing device is of a double series type. In each example, A is an FRP reinforcing material to be fixed,
In the first embodiment, X ₁ is a first fixing tool, X ₂ is a second fixing tool, and X ₃ is a third fixing tool. In the second embodiment, X ₁ is the first fixing tool and X ₂ is the second fixing tool.

More specifically, the FRP reinforcing material A is made by impregnating a high-strength, high-elasticity fiber with a thermosetting resin and curing the thermosetting resin to form a continuous body having a predetermined cross-sectional shape and outer diameter dimension. 5 (a), (b), and (c) are the fixing target F in the present invention.
The RP reinforcing material is illustrated. In the example of FIG. 5 (a),
It has a strand structure in which a plurality of composite filaments 1 are twisted together as strands. The composite filament 1 is made of a yarn in which a large number of ultrafine long fibers having high strength and low elongation properties such as carbon fiber, polyaramid fiber, silicon carbide fiber, etc. are assembled, and epoxy resin, unsaturated polyester resin, polyurethane resin, etc. After impregnating a predetermined amount of thermosetting resin, molding with a shaping die and removing excess resin, a powder desiccant such as talc is applied to the surface of the yarn to dry the surface, and the outer periphery of polyester, nylon, etc. A synthetic fiber or a high-strength low-elongation fiber is wrapped or coated by braiding or the like. Then, a plurality of the composite filaments 1 are passed through a twisting machine to be twisted in a desired pitch and in a twisting direction, and heat-treated in this state to cure the impregnated thermosetting resin. In the example of FIG. 5 (b), a thermosetting resin such as an epoxy resin (composite containing reinforcing fibers mainly as a main component of the FRP reinforcing material A ′ obtained in FIG. A cylindrical buffer layer 7 made of (including resin) is provided. In the example of FIG. 5 (c), a plurality of FRP reinforcing materials A ′ shown in FIG. 5 (a) are bundled into a bundle, and a thermosetting resin such as epoxy resin (mainly this is used as a reinforcing fiber) over the required length. A multi-strand type reinforcing material is provided by providing a cylindrical buffer layer 7 made of a composite resin mixed with (1). In the example of FIG. 5 (a), 7 composite filaments 1 are used, and 1
Although it has a × 7 structure, the structure is not limited to this, and although three FRP reinforcing materials A ′ are used in FIG. 5 (c), the structure is not limited to this.

In the first embodiment, the FRP reinforcing material A having the structure shown in FIG. 5A is used, and the first fixing tool X ₁ , the second fixing tool X ₂ and the third fixing tool X _{3 are used.} Are wedge sleeves 3a, 3b and 3c, respectively, wedges 4a, 4b and 4c which form a pair, and wedge sleeves 3a and 3c.
Elastic bodies 6a and 6 in which b and 3c are connected in series and built in
b, 6c and couplers 5a, 5b, 5c for pressing the wedges 4a, 4b, 4c. The wedge sleeves 3a, 3b, 3c and the wedges 4a, 4b, 4
c and the couplers 5a, 5b, 5c are made of a material having high mechanical strength such as steel. Each wedge sleeve 3a,
The outer diameter side of 3b and 3c has a straight cylindrical shape, and the first wedge sleeve 3a located away from the end of the FRP reinforcing material A is provided with a male screw 33 on the outer periphery of the rear end thereof. The wedge sleeve 3c is provided with male screws 32 and 33 on the outer periphery of the front end and the outer periphery of the rear end, respectively.

First coupler 5a to third coupler 5c
Preferably has a polygonal outer shape or has at least one pair of parallel surfaces to facilitate the turning operation. In addition, at least the first coupler 5a and the second coupler 5b include a first wedge sleeve 3a and a second wedge sleeve 3b.
Female screws 50 and 51 are provided at the front end and the rear end so as to have a step portion that can come into contact with the end surface of the. An inner flange 52 is provided at a position near the rear end as a support seat for the elastic bodies 6a, 6b, 6c. In this embodiment, the third coupler 5c has a cap shape which does not have an internal thread at the rear end and ends with the inner flange 52, but the present invention is not limited to this and is the same as the first coupler 5a and the second coupler 5b. May be. As the elastic bodies 6a, 6b, 6c, those having contractibility as physical properties are selected, and coil springs and disc springs are simply used.

The first wedge 4a, the second wedge 4b, and the third wedge 4c form a pair of wedge sleeves 3a, 3 respectively.
It is mounted in the tapered holes 31a, 31b, 31c of b, 3c, and is pressed in the axial direction by the elastic bodies 6a, 6b, 6c,
Each inner diameter surface 40 is in close contact with the FRP reinforcing material A. The first wedge 4a to the third wedge 4c are composed of a plurality of splits (split into two, split into three, etc.) divided so that a cross section perpendicular to the axial direction has an arc shape and has a predetermined clearance in the radial direction. However, in any case, the inner diameter surface 40
7a, 7b, and 7c, the taper surface 4 has a larger thickness as the outer diameter side goes toward the rear end, as shown in FIGS.
1a, 41b, 41c. On the other hand, each of the first wedge sleeve 3a to the third wedge sleeve 3c has a tapered hole 31a that widens from one end to the other end in the longitudinal direction on the inner diameter side as shown in FIGS. 6 (a), (b) and (c). , 31
b and 31c are pierced. Each taper hole 31a, 31
It is necessary that the minimum diameter (original diameter) of b and 31c is equal to or larger than the outer diameter of the FRP reinforcing material A. The taper angles α ₁ , α ₂ , α ₃ of the tapered holes 31a, 31b, 31c are
Taper angles α ₁ , α ₂ , of the pair of wedges 4a, 4b, 4c,
alpha ₃ and are consistent respectively, but the present invention is, these first
Taper angle α between the wedge sleeve 3a and the first wedge 4a
_1, the taper angle alpha ₂ of the second wedge sleeve 3b and the second wedge 4b, not equal to the taper angle alpha ₃ of third wedge sleeve 3c and the third wedge 4c, increases toward the end portion from the mouth of the wedge column The relationship is as follows. That is,
It is configured to have a stepwise relationship of α ₁ <α ₂ <α ₃ .

This is because when the FRP reinforcing material A is tensioned, the fixing force corresponding to the tension force is equally distributed to the wedges 4a, 4b, 4c, and the fixing force to be borne by each wedge is reduced. This is to reduce the concentrated stress generated at the tip of the wedge. The angle may be appropriately set depending on the diameter, structure, friction coefficient, wedge material, length, etc. of the FRP reinforcing material A, but the relative angular difference between α ₁ and α ₂ (α ₂ −α ₁ )
If it is too large, the above effect cannot be achieved, so in the normal case, 1 ° to 4 ° is preferable. Also,
In the case of the first embodiment (triple type), the relative angular difference between α ₂ and α ₃ (α ₃ −
α ₂ ) may be equal to the relative angular difference between α ₁ and α ₂ , but (α ₂ −α ₁ ) ≠
It is preferable that (α ₃ −α ₂ ) and (α ₂ −α ₁ ) <(α ₃ −α ₂ ). The elastic constants of the elastic bodies 6a, 6b, and 6c may be small because a slight pressing force of the wedge is required to increase the frictional force between the wedge and the FRP reinforcing material at the initial stage of tension. The spring constant is elastic body 6a, 6b, 6c
May be the same or different stepwise.

In the first embodiment, the terminal fixing member is constructed as follows. That is, the FRP reinforcing material A is penetrated through the first wedge sleeve 3a, and the first wedge 4a is inserted into the tapered hole 31a of the first wedge sleeve 3a.
With the elastic body 6a in contact with the rear end surface of the wedge 4a, the female screw 50 of the first coupler 5a is attached to the first wedge sleeve 3a.
It is screwed into the male screw 33 of the
Since a is pressed by the elastic body 6a via the inner flange 52, the first wedge 4a advances into the tapered hole 31a of the first wedge sleeve 3a, and the inner surface 40 is FRP reinforced by the wedge effect corresponding to the taper angle α _1. Contact the material A. The second wedge sleeve 3b is screwed into the female screw 51 at the rear end of the first coupler 5a with the male screw 32, and the second wedge 4b is inserted into the tapered hole 31b of the second wedge sleeve 3b. The second wedge 4b is obtained by screwing the distal end side female screw 50 of the second coupler 5b into the second wedge sleeve 3b in a state where the elastic body 6b is arranged on the second wedge 4b.
Is pressed and FR is generated by the wedge action corresponding to the taper angle α _2.
P Reinforcement A contacts. The third wedge sleeve 3c is attached to the female screw 51 on the rear end side of the second coupler 5b.
2, the third wedge 4c is inserted into the tapered hole 31c of the third wedge sleeve 3c, and the elastic body 6c is arranged behind the third wedge 4c so that the female screw 50 on the tip side of the third coupler 5c is attached to the second wedge sleeve. The third wedge 4c is pressed by being screwed into 3c and comes into contact with the FRP reinforcing material A by the wedge action corresponding to the taper angle α ₃ .

In the second embodiment, the FRP reinforcing material A having the structure shown in FIG. 5 (b) is used, and the first fixing tool X ₁ and the second fixing tool X ₂ are wedge sleeves 3 respectively.
a, 3b, wedges 4a, 4b forming a pair with them, and couplers 5a, 5b for pressing wedges 4a, 4b by elastic bodies 6a, 6b which connect wedge sleeves 3a, 3b in series and have a built-in structure. Have Tapered holes 31a, 3 of the first wedge sleeve 3a and the second wedge sleeve 3b
1b has a mouth diameter equal to or larger than the outer diameter of the buffer layer 7. Further, the taper angle α ₁ of the wedge 4a forming a pair with the taper hole 31a corresponds, the taper angle α _{2 of the} wedge 4b forming a pair with the taper hole 31b also corresponds, and α ₁ <α ₂ Have a relationship. These are the same as in the first embodiment. The terminal fixing structure in the second embodiment is as follows. That is, the buffer layer 7 of the FRP reinforcing material A is penetrated through the first wedge sleeve 3a, and the first wedge 4a is inserted into the tapered hole 31a of the first wedge sleeve 3a.
The female screw 50 of the first coupler 5a is screwed onto the male screw 33 of the first wedge sleeve 3a in a state where the elastic body 6a is in contact with the rear end surface of the first wedge 4a, whereby the first wedge 4a has an inner flange. Since the elastic body 6a is pressed via 52, the first wedge 4a advances into the tapered hole 31a of the first wedge sleeve 3a and contacts the buffer layer 7 with the inner diameter surface 40 by the wedge effect corresponding to the taper angle α _1. . Then, the second wedge sleeve 3b is screwed with the male screw 32 to the female screw 51 at the rear end portion of the first coupler 5a,
By inserting the second wedge 4b into the taper hole 31b of the second wedge sleeve 3b and arranging the elastic body 6b behind the second wedge 4b, the female screw 50 on the tip side of the second coupler 5b is screwed into the second wedge sleeve 3b. The second wedge 4b is pressed, and the buffer layer 7 is formed by the wedge action corresponding to the taper angle α _2.
To contact. Since the other structure is the same as that of the first embodiment,
The same parts are designated by the same reference numerals and the description thereof will be omitted.

The present invention is not limited to the above-mentioned embodiment, and includes a case where there are four or more fixing devices. In this case, the relationship between the taper angles is α ₁ <α ₂ <α ₃ <
It goes without saying that αn-1 <αn. Further, the first embodiment can be applied to the FRP reinforcing material A having the structure shown in FIGS. 5B and 5C, and the second embodiment can be applied to the FRP reinforcing material A having the structure shown in FIG. 5A. Is also natural. Further, in the first embodiment, the third coupler 5c may be omitted in some cases,
The third wedge 4c may be driven by a tool similar to a chisel or a hammer.

[0016]

Next, the operation of the embodiment of the present invention will be described. The terminal fixing structure of the present invention is usually applied to both ends of the prestressed concrete form while the FRP reinforcing material A is penetrated. However, in some cases, only one end may be preliminarily applied in a factory or the like before shipment. In the first embodiment, the first wedge sleeve 3a, the first coupler 5a, the second wedge sleeve 3b, the second coupler 5b, the third wedge sleeve 3c, and the third coupler 5c are located far from the end of the FRP reinforcement A. They are connected in series. Then, the first wedge 4a in the first wedge sleeve 3a is moved to the second by the elastic body 6a supported by the first coupler 5a.
The second wedge 4b in the wedge sleeve 3b is pressed from the rear by the elastic body 6b in the second coupler 5b, and the third wedge 4c in the third wedge sleeve 3c is pressed by the elastic body 6c in the third coupler 5c. . Since the first wedges 4a to the third wedges 4c are each divided into a plurality of pieces, they are pushed into the first wedge sleeves 3a to the third wedge sleeves 3c that form a set so as to narrow the interval between the adjacent unit wedge pieces. Rare, each inner diameter 4
0 makes close contact with the FRP reinforcement A. In the second embodiment, the first wedge sleeve 3a, the first coupler 5a, the second wedge sleeve 3b, and the second coupler 5b are connected in series from a position far from the end of the FRP reinforcing material A.
The first wedge 4a in the first wedge sleeve 3a is supported by the elastic body 6a supported by the first coupler 5a, and the second wedge 4b in the second wedge sleeve 3b is supported by the elastic body 6b in the second coupler 5b. Pressed from behind. Since the first wedge 4a and the second wedge 4b are each divided into a plurality of pieces, they are pushed into the first wedge sleeve 3a and the third wedge sleeve 3b that form a pair by narrowing the interval between the adjacent unit wedge pieces. Rarely, each of the inner diameter surfaces 40 makes close contact with the cylindrical buffer layer 7 on the outer periphery of the FRP reinforcing material. In order to obtain the prestressed concrete, the FRP reinforcing material A tensioning means is used for tensioning in this state. This may be performed by the method illustrated in FIG. That is, FIG. 10 (a) shows that the tension coupler 8 is attached to the last coupler (the second coupler 5b in this example since it is applied to the second embodiment) by a method such as screwing, and the tension coupler 8 is attached to the tension bar. 9 is connected and pulled by a jack or the like. FIG. 10 (b) shows that the pulling force is directly applied to the coupler at the rearmost portion (in this example, the second coupler 5b), the extension portion 53 is provided at the coupler at the rearmost portion, and the tension bar 9 is connected thereto. It was designed to be pulled. FIG. 10 (c) shows a tension coupler 8 having a hooking portion 80 for the front end surface of the first coupler 5a, to which a tension bar 9 is connected for pulling. In this example, the tensioning coupler 8 is composed of two parts 8a and 8b, which are firmly connected to each other by bolts. Alternatively, the rear side body 8b may be provided with a female screw, and this may be screwed into a male screw on the outer circumference of the front side body 8a, or the two body bodies 8a and 8b may be divided into two in the circumferential direction. It may be a structure. Alternatively, the tension coupler 8 may be formed as a single tubular body, and a window hole for inserting the coupler, the wedge sleeve, and the wedge may be provided in the body portion. The tension method is the same in the case of the first embodiment shown in FIG. In any case, after the tension, as shown in FIG.
The spacer 11 may be set between the first wedge sleeve 3a and the first wedge sleeve 3a, and the jack-up may be opened, whereby tension is applied.

When the assembly body is pulled by the above-mentioned method, the plural sets of couplers and the wedge sleeves are connected in series. Therefore, the first wedge 4a to the third wedge 4c (first embodiment), the first wedge 4a Wedge 4a and second wedge 4b
The second embodiment is drawn into the wedge sleeves 3a to 3c (3a and 3b in the second embodiment) which are integrated with the FRP reinforcing material A, respectively, and at the same time, the FRP reinforcing material A (second
In the example, the buffer layer 7) is tightened. Due to such a wedge effect, a fixing force that balances the tension acts on the wedge. Generally, in the case of the wedge method, the stress acting on the FRP reinforcing material in the portion in contact with the wedge is high on the mouth side and low on the edge side, but since the FRP reinforcing material A has a large elongation, the stress concentrates on the mouth side. There is a characteristic that ends up. Therefore, when a single wedge is used, as shown in FIG.
Excessive concentrated stress σ acts on the FRP reinforcing element and thereby destroys the FRP reinforcing material and the buffer layer surrounding the FRP reinforcing material. However, in the present invention, a plurality of wedges are arranged in series, so that the fixing force is dispersed, and the fixing force to be borne by each wedge becomes small. Moreover, the taper angles of the plurality of wedges are not equal, and are gradually increased toward the end of the FRP reinforcing material A. That is, the first
In the embodiment, the first wedge 4a to the third wedge 4c
The taper angle of α ₁ <α ₂ <α ₃ and the first embodiment in the second embodiment.
The taper angles of the wedge 4a and the second wedge 4b are set to α ₁ <α ₂ . With such a taper angle relationship, the concentrated stress near the mouth of each wedge can be reduced.
That is, when the wedge angle is small, the tightening force of the FRP reinforcing material A with respect to a fixed amount of pulling is small. Conversely, when the wedge angle is small, the amount of pulling into the wedge sleeve when the FRP reinforcing material A is fixedly tightened becomes large. Therefore, if the taper angle α ₁ of the first wedge 4a is made smaller than the taper angle α _{2 of} the second wedge 4b, the expansion of the FRP reinforcing material A between the first wedge 4a and the second wedge 4b will be within the wedge sleeve. First wedge 4a with a large amount of pulling in
Is absorbed by a large contact area due to, and the tension force can be distributed to the first wedge 4a and the second wedge 4b. Then, according to the same principle, the elongation of the FRP reinforcing material A between the second wedge 4b and the third wedge 4c is absorbed by the second wedge 4b, so that the tension force is dispersed between the second wedge 4b and the third wedge 4c. You can take charge. Thus, the tension of FRP reinforcement A is 3
Since the wedges are dispersed into individual wedges, the fixing force corresponding to the tension is shared by the three wedges, and the fixing force that each bears is reduced, so as shown in Fig. 8, near the mouth of each wedge. M
The concentrated stresses σ ₁ , σ ₂ , and σ ₃ of ₁ , M ₂ , and M ₃ can be reduced, and fixing can be performed for a long time.

Specific examples of the present invention are as follows. Example 1 A high-strength carbon fiber yarn having a diameter of 0.007 mm and a number of 12,000 filaments was impregnated with 35% by weight of an epoxy resin, and a plurality of prepreg-formed products were twisted together, and a polyester fiber was wound around the outer periphery. A strand is formed, and further, this strand is twisted with one core and six strands on the side. Finally, heat treatment is performed to cure the epoxy resin, and 1 x with an outer diameter of 12.5 mm.
An FRP reinforcing material having a strand structure of 7 was obtained. The fixing structure used in the first embodiment. 1st Kusabisuribu to 1st
3 wedge sleeves are made of steel and have an outside diameter of 55 m
Both m and length are 70 mm. The first wedge to the third wedge are made of steel and divided into three wedges, each having an inner diameter of 12.2 mm and a length of 70 mm, and each of the three divided portions has a clearance of 1.5 mm. In addition, both have irregularities with a pitch of 1.0 mm and a depth of 0.4 mm on the inner surface. First Kusabisuri - Bed a first wedge Te - Pa - angle alpha ₁ is 4.5 °, the second wedge sleeve and the second wedge Te - Pa - angle alpha ₂ is 6.5 °, and the third wedge sleeve The taper angle α ₃ of the third wedge was set to 10 °. First
The couplers or third couplers were made of steel and had an outer diameter of 65 mm, and the wedge-sleeve spacing was 40 mm between the first and second wedges and between the second and third wedges. As the elastic body, a coil spring having a spring constant of 3 kgf / mm was used.
By using the wedge row, the method shown in FIG. 10 was used to tension the FRP reinforcing material at 8,700 kgf corresponding to 60% of the guaranteed breaking load of 14,500 kgf and hold it for 24 hours. As a result, there was no abnormality and stable fixing could be achieved.

Concrete Example 2 As the FRP reinforcing material, the same one as used in Concrete Example 1 was used, and a two-liquid mixed type epoxy resin was applied over the end portion 300 mm to form a cylindrical buffer layer having a diameter of 12.8 mm. did. The fixing structure uses the second embodiment, the first wedge,
A wedge row consisting of two rows of the second wedge was constructed. First,
The outer diameter of each of the second wedge sleeves is 60 mm, and the length thereof is 110 mm. First wedge and second
For each wedge, a three-piece type with an inner diameter of 12.4 mm and a length of 110 mm was used. First wedge sleeve and first
The taper angle α _{1 of the} wedge was 4.5 °, the taper angle α ₂ of the second wedge sleeve and the second wedge was 7.5 °, and the distance between the first and second wedge sleeves was 50 mm. Similarly, using this wedge row, the guaranteed breaking load of FRP reinforcement 14,50
The strain was maintained at 8,700 kgf, which corresponds to 60% of 0 kgf, and kept for 24 hours. As a result, there was no abnormality and stable fixing could be achieved.

[0020]

According to the present invention described above, a plurality of wedge sleeves are connected by a coupler, wedges are mounted in each wedge sleeve, and they are pressed by elastic bodies having the coupler as a supporting surface, respectively. Moreover, the angle of each wedge is not uniform, but is gradually increased from the mouth to the end of the wedge row. Therefore, when the FRP reinforcing material is tensioned, the elongation of the FRP reinforcing material is absorbed between the wedges, and the fixing force corresponding to the tension force can be distributed to the wedges substantially equally. For this reason, the fixing force to be borne by each wedge becomes small, and the concentrated stress generated at the tip of each wedge can be reduced. As a result, F
Since the delayed fracture of the RP reinforcing material is prevented, it is possible to obtain the excellent effect that it is possible to achieve stable fixation capable of withstanding continuous tension of 24 hours or more corresponding to the concrete curing time in the prestressed concrete.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a first embodiment of a terminal fixing structure of an FRP reinforcing material according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a side view showing a second embodiment of the terminal fixing structure of the FRP reinforcing material according to the present invention.

FIG. 4 is a partially cutaway vertical side view showing a second embodiment of the terminal fixing structure of the FRP reinforcing material according to the present invention.

FIG. 5 is a cross-sectional view illustrating an FRP reinforcing material applied in the present invention.

FIG. 6 is a first wedge sleeve to a third wedge according to the present invention.
It is sectional drawing of a wedge sleeve.

FIG. 7 is a cross-sectional view of first to third wedges according to the present invention.

FIG. 8 is a diagram showing a distribution of concentrated stress acting on the FRP reinforcing material when the present invention is adopted.

FIG. 9 is a diagram showing a concentrated stress distribution acting on the FRP reinforcing material when only one set of wedge sleeve and wedge is used.

FIG. 10 is a partially cutaway side view illustrating a tightening method according to the present invention.

FIG. 11 is a side view showing a tension applied state in the present invention.

[Description of Reference Signs] A FRP reinforcing material X ₁ First fixing tool X ₂ Second fixing tool X ₃ Third fixing tool 3a, 3b, 3c Wedge sleeve 4a, 4b, 4c Wedge 5a, 5b, 5c Coupler 6a, 6b, 6c Elastic body α ₁ , α ₂ , α ₃ taper angle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area E04G 21/12 104 C // B29L 31:10

Claims (3)

[Claims] 1. A wedge sleeve covered with an FRP reinforcing material made of a composite of high strength and high elasticity fiber and a thermosetting resin,
Behind the first fixing device, which comprises a coupler connected to the rear part of the wedge sleeve, and a wedge that is paired with the wedge sleeve and is pushed between the FRP reinforcing material and the wedge sleeve by an elastic body arranged in the coupler, A wedge sleeve having a screw for connecting the coupler, a coupler connected to the rear of the wedge sleeve, and a wedge sleeve, which is paired with the elastic body disposed inside the coupler and is pushed between the FRP reinforcing material and the wedge sleeve. One or more fixing members having a wedge are provided in series, and the taper angle α _{1 of the} wedge is
The terminal fixing structure of the FRP reinforcing material, characterized in that the taper angle αn of the wedge behind this is α ₁ <αn. 2. The number of subsequent fixing devices is two, and the relationship between the wedge taper angles α ₂ and α ₃ of the _two fixing devices and the wedge taper angle α _{1 of} the first fixing device is α ₁ <α. The terminal fixing structure of the FRP reinforcing material according to claim 1, wherein ₂ <α ₃ . 3. The terminal fixing structure for an FRP reinforcing material according to claim 1, comprising a buffer layer surrounding the terminal area of the FRP reinforcing material.