JPH0325666B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a method for tensioning and fixing FRP ropes used as tension members for prestressed concrete structures, ropes for joining marine structures, etc. .

(Conventional technology) The conventional tension fixing method for FRP ropes is as follows:
As shown in the figure, the inner circumferential surface of the wedge W inserted into the through hole of the anchor head H is made uneven, and this inner circumferential surface is brought into contact with the outer circumference of the end of the FRP rope R. The end of the FRP rope R was held and the anchor head H was pulled using a jack (not shown) to fix the rope R under tension.

(Problems to be Solved by the Invention) Although FRP ropes have high tensile strength, their interlaminar shear strength and compressive strength are extremely low, and their surfaces are weak, making them susceptible to damage. Therefore, in the above-mentioned conventional case, the inner peripheral surface of the wedge W is uneven, and stress concentration on the uneven portion causes the rope R to
breaks below the tensile strength, making it impossible to fully utilize the tensile strength in the longitudinal direction. In addition, if a wedge with a smooth inner circumferential surface is used, the FRP rope R will slip out of the center hole of the wedge due to its extremely slippery surface during the tension fixing operation, making it impossible to tension the rope R. First, even if tension fixing could be achieved, the fixing efficiency varied widely, and it was extremely difficult to perform stable tension fixing.

In view of the above-mentioned drawbacks of the conventional art, the present invention maintains sufficient tension without damaging or coming off the terminal even when prestressing tension is applied to the FRP rope by pulling the terminal. The purpose of the present invention is to provide a tension fixing method for an FRP rope that can perform stable tension fixing.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a wedge which is made up of a plurality of vertically divided bodies and has a conical outer peripheral surface as a whole, and a tapered wedge into which the wedge is inserted. In the method for tension fixing an FRP rope using an anchor head having a through hole, the wedge has an FRP
The FRP rope is provided with a center hole having a smooth inner circumferential surface through which the FRP rope is inserted, and an engaging member that engages with the outer circumferential surface of the FRP rope is placed near the wedge on the outside of the anchor head. fixed in place;
Applying temporary tension to the FRP rope via the anchor head, and using the temporary tension to press the end face of the wedge with the engagement member to push the wedge into the through hole of the anchor head, the above at predetermined intervals that match the distance between both ends of the target structure.
The anchor head is fixed to two locations on the FRP rope, and then the full tension for prestressing is applied to the FRP rope via the anchor head, and the FRP rope is fixed at a predetermined location on the target structure. It is characterized by establishing tension.

(Function) As described above, the method for tension fixing an FRP rope according to the present invention involves inserting the FRP rope into the tapered through hole of the anchor head, and then inserting the FRP rope into the anchor head, which is made up of a plurality of vertically divided bodies and whose outer circumferential surface as a whole has a conical shape. The rope is positioned in the smooth center hole of the wedge, the wedge is inserted between the rope and the through hole, and the engagement member that is close to the wedge and engages with the outer peripheral surface of the rope is inserted into the rope. is fixed at a predetermined position, a temporary tension is applied to the rope via the anchor head, and the end surface of the wedge is pressed by the engagement member using the temporary tension to push the wedge into the through hole of the anchor head. , the FRP is placed at a predetermined interval that matches the distance between both ends of the target structure.
Securely fix the anchor head in two places on the rope. After that, FRP is attached via the anchor head.
When the prestressing tension is applied to the FRP rope, the inner peripheral surface of the center hole of the wedge is smooth, so the FRP rope will not be damaged and the anchor head will be fixed in place by the wedge action. Therefore, it is stably fixed under tension at a predetermined location on the target structure without slipping out.

(Example) Next, an example of the present invention will be described with reference to the drawings, taking as an example a case where FRP ropes are used as PC tension members and a plurality of ropes are simultaneously pulled and tensioned.

FIG. 1 is a longitudinal cross-sectional view showing a main part of a tension fixing method for an FRP rope according to an embodiment of the present invention.

In the same figure, an FRP rope 2 is inserted into a tapered through hole 1a of an anchor head 1, and a wedge 3, which is made up of a plurality of vertically divided bodies and has a conical outer surface as a whole, has a smooth central hole 3a. The rope 2 is positioned, the wedge 3 is inserted between the rope 2 and the inner circumference of the through hole 1a, and the engagement member 4 that is close to the wedge 3 and engages with the outer circumferential surface of the rope 2 is used to hold the rope 2 at a predetermined position. clamping the position and fixing the engaging member 4 at the predetermined position,
A temporary tension force is applied to the rope 2 through the anchor head 1, and the end face of the wedge 3 is pressed by the side surface of the engagement member 4 using the temporary tension force to push the wedge 3 into the through hole 1a of the anchor head 1. I can push it. In this way, the FRP is placed at a predetermined interval that matches the distance between both ends of the concrete structure 6 as the target structure.
Anchor head 1 is fixed to two places on rope 2 made of rope. After that, FRP is connected via anchor head 1.
A prestressing tension is applied to the FRP rope 2, the FRP rope 2 is stretched, and the fixing nut 19 is turned to contact the bearing plate 5, so that it is stably tensioned at a predetermined location on the concrete structure 6. It is something that makes you

The FRP rope 2 is made by twisting together a plurality of wire rods made of matrix resin and a plurality of single fibers. The fibers are threaded, drawn, covered with a covering material, twisted, and molded and cured.The single fibers are preferably inorganic glass fibers, carbon fibers, organic aromatic polyamide fibers, etc., and the matrix resin Thermosetting resins such as epoxy resins, unsaturated polyester resins, and diallyl phthalate resins containing curing agents are suitable.

Figures 3a and 3b are side views of the wedge, respectively.

The wedge 3 is made of two vertically divided bodies made of a corrosion-resistant material such as ceramics or metal, has a conical outer peripheral surface 3b as a whole, and has a center hole 3a through which the rope 2 is inserted. The diameters of both ends of the rope 3a are slightly larger than the diameter of the rope 2 itself and spread outward to prevent unnecessary external force from being applied to the rope 2, and the mutually facing surfaces 3c are uniformly spread by an appropriate thickness. A stepped groove 3e is provided along the outer periphery near the end on the large diameter side. Further, the wedge 3 has an inner circumferential surface 3d that is smooth and has no irregularities, and is inserted into the through hole 1a of the anchor head 1.

FIG. 4 is a perspective view showing the engaging member.

The engaging member 4 has a pair of clamping pieces 4a, 4a, and each clamping piece 4a, 4a has an uneven engagement surface 4b, 4b at the tip that engages with the outer periphery of the rope 2, and has a handle portion. The tip can be opened and closed by opening and closing operations of 4c and 4c, and the side surface is placed in contact with the end surface of the retaining plate 7 interposed between the wedge 3 and the wedge 3. The engaging member 4 sandwiches the outer peripheral surface of the rope 2 between the engaging surfaces 4b, 4b, grips the handle portions 4c, 4c, and presses from the outer periphery to grip the rope 2 (not shown). When the claw is hooked, it is held in that state and fixed in a predetermined position, and when the claw is removed, the holding is released.

The retaining plate 7 is attached to the anchor head 1
It has the shape of a disc with a slightly smaller diameter, and has through holes 7a and 7b through which the tension rod 11 and rope 2 are inserted, respectively, and a through hole (not shown) corresponding to the small female screw 1d of the anchor head 1. A bolt (not shown) that is inserted into the anchor head 1 with a loose fit is screwed into a small female screw 1d, and is attached to the anchor head 1 so as to be accessible to the anchor head 1, thereby preventing the wedge 3 from shifting. FIG. 3 is a longitudinal sectional view showing an example in which a mating member is used. The engaging member 8 in this case is
A cylindrical socket 9 corresponding to each rope and arranged close to the wedge 3 with a retaining plate 7 interposed therebetween;
9 and uneven wedges 10, 10. The socket 9 has a tapered through hole into which a concave-convex wedge 10 is inserted, and the concave-convex wedge 10 has concavities and convexities formed on the contact surface to the rope 2 as in each of the above cases. It is fixed at a predetermined location on the rope 2 by the wedge action of 10.

The bearing pressure plate 5 has a rectangular plate shape that is sufficiently larger than the outer shape of the fixing nut 19, etc., and is shown in FIGS.
As shown in FIG.
It is fitted into a recess formed at the end of the holder and fixed.

As shown in FIGS. 6a and 6b, the center hole jack 13 for tensioning the rope 2 includes a ram chair 14 whose tip end surface is in contact with a bearing plate 5 provided on the end surface of the concrete structure 6, and a tension rod 11. The cylinder 15 has a center hole 12 through which the tension rod 12 is inserted, and a ram (not shown) is provided, and the movement of the ram causes the tightening nut 1 to be screwed onto the tip of the anchor head 1 and the tension rod 11.
8 to apply tension to the rope 2.

The fixing nut 19 is screwed into a male thread 1e on the outer periphery of the anchor head 1, and has a plurality of holes 19 on the outer periphery.
a, and is turned by hooking a hook spanner (not shown) into this hole 19a. And fixed nut 19
When rope 2 is stretched under tension,
By turning the rope, it is brought closer to the pressure plate 5 by an amount commensurate with its elongation, and has the function of transmitting the tension force of the rope 2 to the pressure plate 5 while in contact with the outer surface of the pressure plate 5.

Next, an example of the tension fixing method for an FRP rope according to the present invention will be explained using a concrete structure as an example.

Figures 6a and 6b show the use of PC tendons as
FIG. 3 is a partial vertical cross-sectional view showing a method for fixing an FRP rope. In Figure a, one of the two anchor heads 1 (left end) with one rope 2 inserted through each through hole 1a is placed outside the bearing plate 5, taking into consideration the elongation of the rope 2 when tensioned. With the other (right end) facing oppositely to the one, the wedges 3 are placed at predetermined positions with the outer ends facing the center hole 5a of the bearing plate 5 from inside the sheath 16, and the wedges 3 are inserted into each of the through holes 1a. After that, install the retaining plate 17,
At the left end of each rope 2, an engaging member 4 shown in FIG. An engaging member 8 shown in FIG. 5 is fixed to each rope 2 at a predetermined position.

6a, the tip of the tension rod 11 passing through the through hole 7a of the retaining plate 7 is screwed into the female thread 1b of the anchor head 1 at the right end as shown in FIG. 2b. Attach to anchor head 1. Next, the center hole jack 1 is set by inserting the tension rod 11 into the center hole 12 of the center hole jack 13 supported by the ram chair 14 which is in contact with the bearing pressure plate 5, and the tension rod 11 protruding from the end thereof is inserted. By screwing the tightening nut 18 onto the tip and with the fixing nut 19 screwed onto the outer periphery of the anchor head 1 at the left end in contact with the bearing pressure plate 5, the center hole jack 13 is extended. A temporary tension force is applied to the rope 2 through both anchor heads 1, 1, and the rope 2 is
Stretch. At this time, at the beginning of provisional tension,
There is almost no wedging action of the wedges 3, 3, and the rope 2 is in a state of sliding against the smooth inner peripheral surface 3d of the center hole 3a of the wedges 3, 3. Both wedges 3 and 3 are pressed by their respective engaging members 4 and 8 and pushed into the through hole 1a while pulling the rope 2 through the anchor head 1, so that the wedge 3 is sufficiently pushed into the through hole 14. , the anchor head 1 is firmly fixed to two locations of the FRP rope at a predetermined interval that matches the distance between both ends of the concrete structure 6. In this state, the main tension force for prestressing is applied by the center hole jack 13 to stretch the rope 2 until the right anchor head 1 reaches the outside of the support plate 5. The fixing nut 19 on the right end side is separated from the bearing pressure plate 5. In this state, the wedge 3 is fully pushed into the through hole 1a and the anchor heads 1, 1 are fixed to the rope 2, so the engagement member 4
and 8 are no longer required, the rope 2 including the part that was damaged on the outer periphery by being held between the engaging members 4 and 8
At the same time, both the engaging members 4 and 8 are removed, and as shown in FIG. 19a with a hook spanner (not shown) to bring it into contact with the bearing pressure plate 5, to apply the required main tension force for prestress to each rope 2, and to fix both ends of the rope 2 to the concrete structure 6. .

When applying the main tension to the rope 2,
When the tensile stress of the rope 2 is large and a large compressive force is applied to the rope 2 from the outer periphery, the rope 2 will
Since it is made of FRP, it will normally break even if the tensile strength is lower than that, but since the inner circumferential surface 3d of the wedge 3 is smooth,
It is possible to prevent stress concentration on the rope 2 received from the inner circumferential surface 3d, and to average this stress along the length direction of the wedge 3, thereby preventing the rope 2 from breaking. Furthermore, when the tensile stress of the rope 2 is small, the compressive force acting on the rope 2 from the wedge 3 is also small, and in addition, since the surface of the rope 2 is slippery, the frictional force that resists the tension force is exerted between the wedge 3 and the rope 2. As a result, relative movement occurs between the wedge 3 and the rope 2, causing the wedge 3 to slip through, and the wedge 3 itself does not function as a fixing device. However, the engagement member 4 or 8 can prevent the rope 2 from slipping out. That is, the engaging members 4 and 8 bite into the rope 2 with a predetermined load from the outer periphery due to the unevenness of the abutment surface, and become integrated with the rope 2, and also use the temporary tension of the rope 2 to hold the wedge 3 in the anchor head. 1 through hole 1
a to sufficiently exert a wedge action, thereby reliably preventing the rope 2 from slipping through.

Next, when the main tension is applied from this state, since the rope 2 does not slip through, the wedge action of the wedge 3 becomes strong, and the entire tensile force of the rope 2 is absorbed by the frictional force of the wedge. become able to. Therefore, regardless of the magnitude of the tension, the tensile force acting on the rope 2 at the engaging member 4 is very small, and the rope 2 will not break even if the compressive force from the outer periphery is large.

The tension fixing method for FRP ropes according to the present invention can be applied to ropes for joining structures near the coast, terminal processing of communication cables that are lightweight and require high tensile strength and electrical insulation, and FRP ropes as industrial reinforcing materials. The FRP rope can be of any type such as spiral type, strand type, etc., and the wedge 3 is not limited to two parts but can be divided into three or more parts. .

Furthermore, the engaging member shown in FIG. 7 may be used. In this case, the engagement member is composed of a cylindrical adhesive sleeve 20 disposed close to the wedge 3 via the retaining plate 7, and an adhesive 21 filled in the adhesive sleeve 20. The adhesive sleeve 20 has a through hole 20a in the center of both end plates, into which the rope 2 is inserted, and is fixed to a predetermined position of the rope 2 by an adhesive 21 filled inside. Furthermore, it is also possible to use a vise as the engaging member in place of the engaging member shown in FIG.

(Effects of the Invention) The present invention is constructed as described above, has a center hole through which the FRP rope is inserted, and uses a wedge with a smooth inner peripheral surface of the center hole to pull the end of the FRP rope. Even if tension is applied to the FRP rope, its end will not be damaged by the inner peripheral surface of the center hole of the wedge, and temporary tension can be applied to the FRP rope through the anchor head and the temporary tension can be utilized. Then, press the end face of the wedge with the engaging member fixed to the FRP rope,
Push the wedge into the through hole of the anchor head, fix the anchor head to two points of the FRP rope at a predetermined interval that matches the distance between both ends of the concrete structure, and then insert the FRP rope through the anchor head. By applying the pre-stressing tension to the FRP rope and fixing the FRP rope under tension to a predetermined location on the target structure, sufficient tension can be maintained to prevent the FRP rope from slipping out of the center hole of the wedge. Capable of holding force and applying force to the target structure.
Stable tension fixation of FRP ropes can be performed.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing the main parts of a tension fixing method for an FRP rope according to an embodiment of the present invention, FIG. 2a is a front view showing the anchor head, and FIG. A sectional view, FIGS. 3a and 3b are a side view and a front view showing the wedge, respectively, FIG. 4 is a perspective view showing the engaging member, and FIG. 5 is a longitudinal sectional view showing another example of the engaging member. Figure 6 a and b are FRP as PC tendons.
Partial longitudinal side view showing the fixing method of the manufactured rope, No. 7
The figure is a longitudinal sectional view showing an example of an engaging member separate from the above-mentioned case, and FIG. 8 is a longitudinal sectional view showing the main part of the conventional tension fixing method. 1: Anchor head, 1a: Through hole, 2... Rope, 3: Wedge, 3a: Center hole, 3b: Outer peripheral surface, 3
d: Inner peripheral surface, 4, 8: Engagement member.

Claims (1)

[Claims] 1. Uses a wedge that is made up of a plurality of vertically divided bodies and has a conical outer peripheral surface as a whole, and an anchor head that has a tapered through hole into which the wedge is inserted.
In the tension fixing method for an FRP rope, the wedge is provided with a center hole having a smooth inner circumferential surface through which the FRP rope is inserted, and the wedge is provided adjacent to the wedge on the outside of the anchor head and the outer periphery of the FRP rope is An engaging member that engages with the surface is fixed at a predetermined position on the FRP rope, and the
Applying temporary tension to the FRP rope and using the temporary tension to press the end face of the wedge with the engagement member to push the wedge into the through hole of the anchor head,
The anchor head is fixed to two locations of the FRP rope at a predetermined interval that matches the distance between both ends of the target structure, and then the FRP rope is under tension for prestressing via the anchor head. A method for tension-fixing an FRP rope, comprising applying force to tension-fix the FRP rope at a predetermined location of the target structure.