JPH06287949A - Fixing device of frp cable - Google Patents

Abstract

PURPOSE:To prevent the rupture of a cable by fixing a fixing device formed of a female cone having a projection and a base having a slide groove to one end of the cable, bringing the projection into contact with the slide groove when a tension is imparted to the cable, and protruding the projection into the groove when an excessive load acts thereon. CONSTITUTION:A fixing device 10 formed of a wedge 11, a female cone 12, and a base 13 is fixed to one end of a FRP cable 20 having no property corresponding to the yielding phenomenon of PC steel. The projection 124 of the female cone 12 is set in such a manner that it has a prescribed tension when a tension is imparted to the cable 20 to bring the projection 124 into contact with the slide groove 132 of the base 13. When an unexpected excessive load acts on the cable 20, the projection 124 is protruded into the slide groove 132. Thus, the rupture of the cable can be prevented even when the excessive load by an earthquake acts thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an FRP cable fixing device for prestressed concrete or underground anchors.

[0002]

2. Description of the Related Art The application of FRP cables as tension materials for prestressed concrete structures has been studied. Comparing FRP cable with steel PC steel, its advantages are light weight and easy handling. Has excellent durability without worrying about rusting. It is a non-magnetic material. High breaking strength. And so on. Further, as a drawback when using the FRP cable, the shear strength is small. There is no property equivalent to the yield phenomenon of PC steel. And so on.

[0003]

[Problems to be Solved by the Invention] The conventional fixing technique for FRP cables has the following problems. FR
The P cable does not have the property equivalent to the yield phenomenon of PC steel. That is, when both ends of the FRP cable are fixed and the tension applied to the cable is increased, the FRP cable is ruptured in tension due to brittle fracture while maintaining its elastic properties. Therefore, F
When an unexpectedly large load is applied to a structure that uses RP cables, the member yield strength is momentarily exceeded,
It does not exhibit the tenacity of a structure made of PC steel material, and takes a very dangerous failure mode such as sudden failure.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to impart a yield phenomenon corresponding to plastic deformation of PC steel to an FRP cable used as a tension material, An object of the present invention is to provide a fixing device for an FRP cable that avoids instantaneous collapse of a structure using the FRP cable.

[0005]

That is, the present invention comprises a tubular member for supporting a cable and an outer barrel for slidably accommodating the tubular member, and the tubular member and the outer barrel face each other. The fixing device for an FRP cable has protrusions and slide grooves that allow the protrusions to be fitted when a constant tension acts on the cable.

[0006]

Embodiment 1 An embodiment of the present invention will be described below with reference to the drawings. Although the present embodiment is the fixing device for fixing the FRP cable in the structure, the present invention can be applied to the case of fixing the FRP cable in the ground.

<A> Fixing Device (FIG. 1) FIG. 1 shows a fixing device 10 according to the present invention. Fixing device 10
Is composed of a wedge 11 having a tapered shape that holds the FRP cable 20, a female cone 12 to which the wedge 11 is attached, and a pedestal 13 that accommodates the female cone 12.
Each part will be described in detail below.

<B> Wedge (Fig. 1) The wedge 11 has a tapered shape and is an FR which is to be fixed to the central shaft portion.
A truncated cone having a through hole 111 having a diameter slightly smaller than the outer diameter of the P cable 20 is vertically divided into a plurality of pieces. The wedge 11 has a ridge formed in the circumferential direction on the inner surface of the through hole 111, and the FRP cable 20 in the through hole 111 is formed.
Can be gripped. The wedge 11 may be any other known wedge.

<C> Female Cone (FIG. 1) The female cone 12 is a cylindrical body in which a large diameter portion 121 and a small diameter portion 122 are connected in an axial direction, and the wedge 11 is provided at the center axis portion thereof.
A taper hole 123 for mounting is installed. Further, the female cone 12 has a plurality of projections 124 radially provided on the outer peripheral surface of the large-diameter portion 121 from the central axis portion. The cross section of the protrusion 124 in the protruding direction has a shape in which the side parallel to the central axis of the rectangle is swollen, but it may be circular, elliptical, or any other shape.

<D> Pedestal (FIG. 1) The pedestal 13 is a portion for supporting the female cone 12,
It is formed of a cylindrical body having an accommodation hole 131 for accommodating the female cone 12. A slide groove 132 is formed on the inner peripheral surface of the accommodation hole 131 in the axial direction. The slide groove 132 is a groove through which the protrusion 124 of the female cone 12 slides, is arranged corresponding to the protruding position of the protrusion 124, and is set to be deeper than the protrusion length of the protrusion 124. The groove width of the slide groove 132 is set to be narrower than the maximum lateral width of the protrusion 124. That is, the FRP cable 20 used
Before the breaking tension force of the
Slide groove 132 so that it press-fits into 2 and slides
The groove width and the maximum lateral width of the protrusion 124 may be set. The setting of the groove width of the slide groove 132 and the lateral width of the protrusion 124 varies depending on the materials of the female cone 12 and the pedestal 13.
Further, the groove width of the slide groove 132 may be formed so as to become narrower in the sliding direction of the protrusion 124.

<E> FRP cable (FIG. 1) The FRP cable 20 is a FRP cable that does not have a yield capability, and is made of, for example, a new material fiber, carbon, glass, aramid or the like.

[0012]

Next, a method of fixing the FRP cable will be described. <B> Fixing Device Set (FIG. 2) The fixing device 10 is attached to one end of the FRP cable 20 extending from the structure 30. That is, the FRP cable 20 is inserted into the hole 41, the pressure support plate 40 is installed in the structure 30, and the small diameter portion 122 of the female cone 12 is inserted into the accommodation hole 123 of the pedestal 13.
Is inserted, the wedge 11 is mounted in the tapered hole 123 of the female cone 12, and the FRP cable 20 is sequentially inserted and set on the pressure support plate 40. Then, an initial tension is applied to the other end side of the FRP cable 20 (not shown) to fix the FRP cable 20. At the time of this fixing, the protrusion 124 of the female cone 12 is supported by the end of the slide groove 132. Regarding the pedestal 13 and the bearing plate 40, the pedestal 13 and the bearing plate 4
In some cases, 0 is integrally formed, or in some cases, the outer shape of the pedestal 13 is set to a predetermined size so as to serve also as a bearing plate.

<B> When tension increases (FIG. 3) When an excessive load is applied to the structure 30 due to an earthquake or the like, the FRP
In some cases, a tensile force higher than the breaking tension force is applied to the cable 20. However, before the tension acting on the FRP cable 20 reaches the breaking tension, the tension of the FRP cable 20 causes the female cone 12 to be inserted into the slide groove 132 of the pedestal 13.
Of the projection 124 is retracted. Therefore, the fixing end portion of the FRP cable 20 moves in the tension direction, and the tension force acting on the FRP cable 20 is reduced. Therefore, FRP
Even if tensile force more than breaking tension is applied to the cable 20,
It is possible to fix the FRP cable 20 without breaking it.

Next, the yield capability of the FRP cable will be described. <C> Yield capacity (FIGS. 4, 5, and 6) As shown in FIG. 4, when the tensile force of the fixed FRP cable 20 is increased, the tension force acting on the FRP cable 20 is also increased, and the tension is increased. When the force exceeds a specified value, the protrusion 12
4 enters the slide groove 132. Further, when the tensile force is continuously increased, the protrusion 124 abuts on the pressure bearing plate 40, and the tension force acting on the FRP cable 20 increases without sliding further. The above process will be described with reference to the graph of FIG.
Since the P cable tensile force acts on the FRP cable 20 as it is, as the FRP cable tensile force increases, the FRP cable increases.
The tension acting on the cable 20 also increases. And
When the tension force acting on the FRP cable reaches a predetermined value,
, The protrusion 124 begins to slide, and at this time the FRP
Even if the cable pulling force increases, the tension force acting on the FRP cable 20 hardly changes. When the protrusion 124 slides to the end portion of the slide groove 132, that is, the position of and contacts the pressure bearing plate 40, the tension force acting in the FRP cable 20 also increases as the FRP cable tensile force increases. When the tension force acting on the FRP cable 20 reaches the breaking tension force T, the FRP cable 20 breaks. FIG. 6 shows a graph of the FRP cable tensile force versus the tension force characteristic acting on the FRP cable by the conventional fixing device. In contrast to the conventional tension characteristic of FIG. 6, in FIG. 5, the FRP cable 2 which does not have the yielding ability by the fixing method of the present invention.
0 has been used to obtain tension characteristics similar to FRP cables with yield capability.

[0015]

Second Embodiment As shown in FIG. 7, in the fixing device according to the present invention, the protrusion 124 of the first embodiment is provided on the inner peripheral surface of the accommodation hole 131 of the pedestal 13 and the slide groove 132 is formed in the large size of the female cone 12. It may be engraved on the outer peripheral surface of the diameter portion 121.

[0016]

[Third Embodiment] The protrusions 124 and the slide grooves 132 of the first and second embodiments may be formed in combination with the inner peripheral surface of the accommodation hole 131 of the pedestal 13 and the outer peripheral surface of the large diameter portion 121 of the female cone 12, respectively. . That is, the protrusion 124 and the slide groove 132 are formed on the inner peripheral surface of the accommodation hole 131 of the pedestal 13, and the slide groove corresponding to the protrusion 124 and the protrusion corresponding to the slide groove 132 are formed on the outer peripheral surface of the large diameter portion 121 of the female cone 12. Even in this case, it is possible to obtain the same effects as those of the first and second embodiments.

[0017]

[Fourth Embodiment] The supporting means of the cable 20 used in the first to third embodiments is not limited to the wedge 11 and the female cone 12, but the cable 2
A known support structure capable of supporting 0 can be adopted.

[0018]

[Embodiment 5] This embodiment relates to a fixing device and a fixing method when a PC steel material having a yield capability is used for a cable. The protrusion 1 of the female cone 12 shown in FIG. 1 slides when a tension force larger than the tension force to be introduced is applied to the cable 20.
The shape and material of the slide groove 132 of the pedestal 13 and the base 24 are set. Then, when the tension of the cable 20 is fixed, the tension of the cable 20 is increased by a tension force slightly larger than the tension force to be introduced. The fixing device 10 for the cable 20 slides and fixes until the tension force acting on the cable 20 reaches the tension force to be introduced. Therefore, it is possible to reliably introduce the tension force to be introduced into the cable 20.

[0019]

Since the present invention is as described above, the following effects can be obtained. <B> Use an FRP cable that does not have a yield capability and use FR
By sliding the P cable fixing portion with a predetermined tension force, it is possible to impart a tension characteristic equivalent to that of an FRP cable having a yield capability. Therefore, F without the ability to yield
Even if a tensile force exceeding the breaking tension is applied to the RP cable,
The FRP cable can be fixed without breaking.

<B> The settings of the projection of the female cone and the slide groove of the pedestal are adjusted so that the fixing device slides by the tension force to be introduced into the cable. Then, if the cable is tensioned and fixed with a slightly large tension at the time of fixing the cable tension, the fixing device slides and fixes until the tension acting on the cable reaches the tension expected to be introduced. Therefore, even if the initial tension force at the time of tension is excessive, it is not affected, and it is possible to cope with the deformation of the structure and the creep of the ground, and it is possible to surely continue to introduce the effective tension force to the cable.

[Brief description of drawings]

FIG. 1 is a perspective view of a fixing device.

FIG. 2 is a side sectional view of the fixing device.

FIG. 3 is an explanatory diagram of a fixing method.

FIG. 4 is an explanatory diagram of a fixing method.

FIG. 5 is a graph of a FRP cable tension force characteristic graph according to the fixing device of the present invention.

FIG. 6 is a graph of FRP cable tension force characteristics of a conventional fixing device.

FIG. 7 is a perspective view of a fixing device according to a second exemplary embodiment.

Claims (1)

[Claims] 1. A cylindrical member for supporting a cable, and an outer cylinder slidably accommodating the cylindrical member, wherein projections are provided on sliding surfaces of the cylindrical member and the outer cylinder facing each other.
A fixing device for an FRP cable, wherein a slide groove is formed to allow the protrusion to be fitted when a constant tension is applied to the cable.