JPH0640738Y2 - Fixing structure for tension materials - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to a tension material used for a prestressed concorre (hereinafter simply referred to as PC) structure, and more specifically, a tension material using a fiber reinforcement material. It is related to the fixing structure of.

(Conventional structure) As an example of a conventional fixing structure using PC steel, as shown in FIGS. 7 and 8, the end of the PC steel material p immersed in the PC is placed inside the steel fixing part (sleeve) (1). Multiple wedges (2)
(2)… (Inclination angle about 14 °, length is about 3 diameter of tendon.
(4 to 4 times) to fit and fix the same over a required length to form a saw-toothed concavo-convex surface (3) on the inner surface of the wedge (2). ) Bites into the surface of the PC steel material p to prevent slippage between the PC steel material p and the wedge (2).

However, in recent years, a PC tension material using a fiber reinforcing material such as glass fiber for the PC structure has been applied.

This uses a rod formed by molding a glass monofilament having a diameter of several microns with a thermosetting resin as a PC tension member.However, when the PC tension member is applied to the fixing structure, a wedge is used. The saw-toothed concavo-convex surface (3) formed on the inner surface of (2) bites into the surface of the PC tension member p,
There is a defect that sufficient fixing force cannot be obtained because the fiber reinforcing material such as glass fiber on the surface of the sheet is broken or the surface is scraped off by the tensile force.

Therefore, as such a fixing structure for the PC tension material p, there is a fixing structure formed by utilizing the mechanical and physical characteristics of the PC tension material p while utilizing the wedge action of the fixing structure. It is proposed in Japanese Patent Publication No. 60-203762.

That is, in the above invention, the PC tension member p is divided by making a split in the end thereof, a gradient is formed on the outer periphery of the end of the PC tension member p, and a fixing member having an inner hole corresponding to this gradient is provided. PC
It is fitted to the end portion of the tension member p, and further, a fixing resin is filled in a gap between the crack at the end portion of the PC tension member p, the inclined surface of the outer periphery of the PC tension member end and the inner hole of the fixing member. It is a fixing structure.

(Problems to be solved by the invention) As described above, in FIGS. 7 and 8, the PC is immersed in the PC.
A fixing structure in which the end portion of the steel material p is fitted over a required length through a plurality of wedges (2) arranged in a fixing body (sleeve) (1) made of steel, and the wedge (2) Saw-toothed concave-convex surface (3) is formed on the inner surface of the so that the concave-convex surface (3) is caught in the surface of the PC steel material p so as to prevent the slip between the PC steel material p and the wedge (2). When a PC tension material that uses fiber reinforced material such as glass fiber is applied to the fixing structure, the fixing efficiency is significantly reduced because the PC tension material is inherently weaker than the shear strength of PC steel material. Will be done.

That is, the bearing stress generated in the PC tendon p is maximized at the tip portion (2a) of the wedge (2), and the axial stress generated in the PC tendon p at the tip portion (2a) of the wedge (2). Since it becomes the maximum, when the PC tension material p using a fiber reinforcing material such as glass fiber is applied, the tip portion (2a) of the wedge (2) is easily broken.

Furthermore, a concave-convex surface (3) having a saw-tooth shape is formed on the inner surface of the wedge (2), and the uneven surface (3) is engaged with the surface of the PC steel material p so that the PC steel material p and the wedge (2) are formed. Although slip is prevented, a sufficient fixing force can be obtained by breaking the fiber reinforcing material such as glass fiber on the surface of the PC tension material p or scraping the surface by the axial tensile force at this portion. There is a serious problem that the PC tension material p comes off from the fixing body (1) without being obtained.

On the other hand, in the fixing structure proposed in Japanese Patent Application Laid-Open No. 60-203762, fixing is performed by the adhesive force of the fixing resin filled in the gap between the inclined surface of the PC tension member p end outer periphery and the inner hole of the fixing body. Due to this structure, the length of the fixing member is about 15 times the diameter of the PC tension material p.
More than double the length is required and as a result the fuser must be lengthened.

Therefore, the injection amount of the fixing resin to fill the gap becomes large in order to improve the fixing efficiency, and it takes a long time from the injection of the resin to the curing and a great amount of labor is required, which is not suitable for on-site construction. There was a problem with.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention fixes the end portion p1 of the PC tension member p to the fixing member (1) as shown in the sectional view of the main part of FIG.
The fixing structure for a tension member, which is made of fiber reinforced material, in which the PC tension member p is fitted with the wedges (20) and (20) at the end portion p1 of the PC tension member p. In regard to the inclination angle θ1 of the wedge (20), the difference between the inclination angle θ1 of the wedge (20) and the inclination angle θ2 of the fixing body (10) is 0.2.
Inclination angle θ of the fixing body (10) within the range of ° to 2.0 °
In addition to being formed larger than 2, the inner surface of the wedge (20) is 100
The basic structure is a structure with a surface roughness (21) in the range of up to 500 μm, and the inclination angle θ1 of the wedge (20) is 6
A structure was adopted in which the range was more than 0 and 12 ° or less, and the length of the wedge (20) was in the range of 5 to 12 times the diameter of the tendon.

The surface roughness (21) means that iron powder, sand, alumina powder, or other powder having a hardness higher than that of an object to be fixed is fixed to the inner surface of the wedge (20) by adhesion or embedding, This refers to forming irregularities on the surface.

(Operation) As described above, the present invention has a fixing structure of a PC tension member p using a fiber reinforcing material such as glass fiber, and the inclination angle θ1 of the wedge (20) is the same as the inclination angle θ1 of the wedge (20). The difference from the inclination angle θ2 of the fixing body is larger than the inclination angle θ2 of the fixing body (10) within the range of 0.2 ° to 2.0 °, and the inner surface of the wedge (20) is in the range of 100 to 500 μmm. The surface roughness (21) of the wedge was adopted, but this prevents the stress concentration at the tip part (20a) of the wedge and disperses the stress over the entire length of the wedge (20). The wedge (20) tip (20
This is to eliminate the breakage of the PC tension material p in a) and improve the fixing efficiency of the PC tension material.

That is, the difference between the inclination angle θ1 of the wedge (20) and the inclination angle θ2 of the fixing member (10) is 0.2 °.
The inclination angle θ2 of the fixing body (10) within the range of up to 2.0 °
As shown in the graph of FIG. 2, when the difference between the inclination angle θ1 of the wedge (20) and the inclination angle θ2 of the fixing body (10) is less than 0.2 °, the reason why the wedge is formed is larger. Since the tensile force tends to increase and the lateral pressure (grasping force) tends to increase toward the tip of (20), as a result, the PC tendon p is easily broken at the tip (20a) of the wedge (20),
The desired fixing effect cannot be expected.

On the other hand, when the difference between the inclination angle θ1 of the wedge (20) and the inclination angle θ2 of the fixing member (10) is 0.2 ° or more, the tensile force increases toward the tip of the wedge (20) and the lateral pressure (grip) is increased. Force) diminishes, so that only in the part after the wedge (20)
Since the PC tension material p is no longer gripped, the lateral pressure (gripping force) to the PC tension material p is insufficient, and the PC tension material p slips with the wedge (20), and the expected fixing effect cannot be obtained. .

For the above reason, the inclination angle θ1 of the wedge (20) and the fixing member (1
The difference with the inclination angle θ2 in 0) was selected in the range of 0.2 ° to 2.0 °.

And, the inclination angle θ1 of the wedge (20) exceeds 6 °
The optimum range is 12 ° or less.

Because, as shown in the graph of FIG. 3, regarding the relationship between the inclination angle θ1 of the wedge (20) and the breaking load of the PC tension member p, when the inclination angle θ1 is 6 ° or less, the PC tension member is less than 6 °. p
The lateral pressure (grasping force) against is too large, and the PC tension material p easily breaks inside the wedge (20). Also this wedge (20)
However, once it is caught in the fixing body (10), it becomes difficult to remove it, which poses a practical problem.

On the other hand, when the inclination angle θ1 exceeds 12 °, the lateral pressure (grasping force) generated by the wedge (20) biting into the fixing body (10) becomes small, and the PC tension member p slips between itself and the wedge (20). Occurs, the fixing effect is reduced, and the outer shape of the wedge (20) is enlarged.

Next, the reason why the surface roughness (21) within the range of 100 to 500 μm is formed on the inner surface of the wedge (20) is that the wedge (20)
Since the friction coefficient is small when the friction surface between the inner surface of PC and the PC tension member p is smooth, it is necessary to increase the total length L of the wedge (20) in order to grip the PC tension member p until it breaks. is not.

Therefore, according to the present invention, as shown in the end view of FIG. 4A and the sectional view of the main part of FIG.
The unevenness (21) (pitch H1, height H2) of 0 to 500 μm is formed to increase the friction coefficient of the PC tension member p.
Tried to prevent slippage with the wedge (20).

That is, as shown in the graph of FIG.
When it is less than 0 μm, the PC tension material p slips between the wedge (20) and the fixing effect is reduced, while when it exceeds 500 μm, the reinforcing material such as glass fiber mixed in the PC tension material p is generated. Since it breaks, the fixing effect decreases.

The irregularities (21) formed on the inner surface of the wedge (20) are
By adhering powder having a hardness higher than that of a fixed material having a size of 100 to 500 μm or by embedding it, it is possible to form the surface roughness in a substantially uniform state over the entire surface.

Further, as shown in the graph of FIG. 6, the length L of the wedge (20) may be about 5 times or more the diameter D of the PC tendon p.

If the length L of the wedge (20) is less than 5 times the diameter D of the PC tendon p, the lateral pressure per unit area against the PC tendon p becomes large and the wedge (20) This is because the PC tension material p breaks on the inner surface of the sheet and defects such as slip occur.

The PC tension material using fiber reinforced material such as glass fiber in the present invention means the following.

Made of high-polymer fiber such as polyethylene, vinylon, polyacetal, etc. to have high strength by drawing process and have a diameter of 100 μm.
More tension material.

FRP made of glass fiber, aramid fiber, carbon fiber and other high-strength fibers as a reinforcing material, and a tension material in which these fibers are bundled, twisted or braided and cured with a resin.

Tensile material with reinforcing fibers made of metal fibers such as alumina fibers, titanium fibers, boron fibers, and inorganic fibers.

(Example) The fixing structure of the present invention is as described above, and an example will be described below.

Example 1 Tension material ... FRP material with a diameter of 8.0 mm and breaking load of 6400 kg Wedge ... Inclination angle of 9.6 ° Length of 100 mm (steel) Under the condition that 250 μm alumina powder was applied to the inner surface, the wedge (20) was inclined A tension test was conducted using the fixing body (10) in which the difference between the angle θ1 and the inclination angle θ2 of the fixing body (10) was variously changed within the range of 0 ° to 2.4 °. If the difference between the inclination angle θ1 and the inclination angle θ2 of the fixing body (10) is within the range of 0.2 ° to 2.0 °, there is no slip phenomenon, no breakage in the wedge (20), and high fixing strength. It could be confirmed.

Second embodiment Tension material ... FRP material with a diameter of 8.0 mm and a breaking load of 6400 kg Wedge ... Inclined angle 9.6 ° Length 100 mm (steel) Fixing body ... Under the condition of an inclined angle 9.0 °, various kinds of wedges (20) have various inner surfaces. Alumina powder with a particle size was adhered and a tensile test was conducted. As a result, if the average particle size of the powder adhered to the inner surface of the wedge (20) is in the range of 100 to 500 μm, the fixing efficiency is 100%. I got it.

Third Example Tension material ... FRP material with a diameter of 8.0 mm and a breaking load of 6400 kg Wedge ... Length of 100 mm (steel) Inner surface is coated with 250 μm alumina powder Wedge (20) inclination angle θ1 and fixing body (10) Inclination angle θ2
The inclination angle θ1 of the wedge (20) was variously changed, and the inclination angle θ1 of the wedge (20) was changed to 0.6 ° (the inclination angle θ2 of the fixing body (10) was small). If it is less than 6 °, the wedge (20) is likely to be broken at the contact point, and if the inclination angle θ1 of the wedge (20) exceeds 12 °, slipping occurs and sufficient fixing efficiency cannot be obtained. Therefore, the wedge (2
The inclination angle θ1 of 0) is optimal in the range of more than 6 ° and 12 ° or less from the viewpoint of fixing efficiency.

Fourth Example Tension material ... FRP material with a diameter of 8.0 mm and breaking load of 6400 kg Wedge ... Inclination angle of 9.6 ° (steel) Inner surface is coated with 250 μm alumina powder Fixing body ... Inclination angle of 9.0 ° and wedge ( When the length L of 20) was changed in the range of 3 to 12 times the diameter D of the PC tendon p and a tensile test was performed,
If the diameter is less than 5 times the diameter D of the PC tension material p, breakage occurs in the wedge (20) and slippage occurs, which is not preferable, and if it is 5 times or more, 100% fixing efficiency is obtained. .

Therefore, in order to obtain a fixing efficiency of 100%, the length L of the wedge (20) should be 5 times or more the diameter D of the PC tension material. It is very compact in terms of what was needed.

(Effect of device) As described above, according to the fixing structure of the present invention, the bearing stress generated in the PC tension member is minimized at the tip of the wedge, and the PC in the fixing portion is
Since the stress applied to the tension material is averaged, the problem of shearing force can be solved even when applied to PC tension material that uses fiber reinforcement such as glass fiber that is easily broken at the tip of the fixing part. At the same time, there was no breakage in the fixing part of the PC tension material.

Furthermore, a surface roughness in the range of 100-500 μmm is formed on the entire inner surface of the wedge, and this surface roughness adheres to the surface of the PC tension material to prevent slippage between the PC tension material and the wedge (2). Since it is possible to do this, the fiber reinforcement such as glass fiber on the surface of the PC tension material does not break at this part, the surface is not scraped off by the tensile force in the axial direction, and even if the total length of the wedge is shortened Sufficient fixing power was obtained, and the PC tension material did not come off from the fixing body.

On the other hand, the length of the fixing member may be about 5 times or more that of the PC tension member, and the entire fixing portion can be made compact, which is advantageous in terms of on-site construction.

In short, according to the fixing structure of the present invention, the tension member is not broken at the fixing portion using the wedge, and the slip between the wedge and the tension member does not occur at all, so that the fixing efficiency is extremely high and the fixing is performed. The parts can be made compact, and there is an effect that site construction is simple.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a fixing structure of the present invention, FIG. 2 is a graph showing a relationship between a breaking load and a difference between a wedge inclination angle and a fixing body inclination angle, and FIG. 3 is a wedge inclination. A graph showing the relationship between the angle and the breaking load, FIGS. 4A and 4B are end views showing the surface roughness formed on the inner surface of the wedge and a sectional view of the main part, and FIG. 5 shows the inner surface roughness of the wedge and the breaking load. 6 is a graph showing the relationship between the wedge length and the breaking load, FIG. 7 is a sectional view showing a conventional fixing structure, and FIG. 8 is a sectional view showing the main part of the conventional fixing structure. Is. The names of the symbols are as follows. (1), (10) ... Fixing body (sleeve), (2), (20)
… Wedges, (2a), (20a)… Wedge tips, (3), (21)
… Wedge inner surface irregularities, P… Tension material, p1… Tension material end, θ1…
Wedge tilt angle, θ2 ... Fixer (sleeve) tilt angle,
D: diameter of tendon, L: length of wedge.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Toshikazu Minami, 7-2, Doi-cho, Amagasaki City, Hyogo Prefecture Shinko Steel Wire Industry Co., Ltd. (72) Shoji Shirahama, 2-chome, Doi-cho, Amagasaki City, Hyogo Prefecture Shinko Steel Wire Industry Co., Ltd. (72) Inventor Satoshi Akane 7-2 Doi-cho, Amagasaki City, Hyogo Prefecture Shinko Steel Wire Industry Co., Ltd. (72) Nao Okamoto 518-1 Komagaki, Nagareyama City, Chiba Prefecture Mitsui Construction Co., Ltd. In-house technology research institute (56) Reference JP 62-13640 (JP, A) Actually opened 63-184915 (JP, U) Actually opened 54-174211 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A tension member made of a fiber reinforced material in which an end portion of the tension member is fitted to a fixing body to fix the both members over a required length and a wedge is driven into the end portion of the tension member. In the fixing structure, the inclination angle of the wedge is formed to be larger than the inclination angle of the fixing body within a range of 0.2 ° to 2.0 ° in the difference between the inclination angle of the wedge and the inclination angle of the fixing body,
The wedge has an inclination angle in the range of more than 6 ° and not more than 12 °, and the length of the wedge is not less than 5 times and not more than 12 times the diameter of the tendon, and the inner surface thereof. Has a particle size of 10
A fixing structure for a tension member, characterized in that a powder having a hardness higher than that of a fixing member in the range of 0 to 500 μm is fixed on the entire surface to form a surface roughness.