JP2018053469A - Tension force introduction method for tension member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension force introduction method for a tension member which can prevent entry of a degradation factor from an end part of the tension member.SOLUTION: A method of introducing a tension force of a tension member to a tension member of a prestressed concrete has: a tension member disposing step of disposing a first tension member 3 and a second tension member 4 constituting the tension member so as to face each other coaxially; a space-containing concrete member forming step for forming a space-containing concrete member 21 having space 51 for exposing mutually opposed end portions of the first tension member 3 and the second tension member 4, while the first tension member 3 and the second tension member 4 are inserted and fixed in such a manner that end portions thereof separated from each other are not exposed; a tension force introducing step for introducing a tension force in directions approaching each of the first tension member 3 and the second tension member 4 exposed in the space after the space-containing concrete member forming step; and a tension member connecting step for connecting the first tension member 3 and the second tension member 4 to which the tension is introduced, after the tension force introducing step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for introducing tension of a tension material of prestressed concrete.

  Conventionally, when a tension force is introduced into a tension material such as a PC steel material of prestressed concrete, the tension force is introduced from an end portion of the tension material (see, for example, Patent Document 1). After introducing tension to the tension material, the anchoring part between the tension material and concrete is buried with cover concrete or non-shrink mortar.

JP 2014-237951 A

  However, since the end of the tendon is often exposed to the outside, there is a possibility that a deterioration factor that causes deterioration of the concrete or the tendon enters from the end of the tendon.

  Then, an object of this invention is to provide the tension | tensile_strength introduction method of the tension material which can suppress that a deterioration factor penetrate | invades from the edge part of a tension material.

  In order to achieve the above object, a tension material tension introduction method according to the present invention is a tension material introduction method for introducing a tension force into a tension material of prestressed concrete, and a first tension material constituting the tension material. A tensioning material arranging step in which the material and the second tensioning material are opposed to each other and arranged coaxially, and the first tensioning material and the second tensioning material are inserted and fixed so as not to be exposed from each other. An empty concrete member forming step of forming an empty concrete member having an empty portion that exposes opposite ends of the first tendon and the second tendon, and the empty concrete member. After the forming step, a tension force introduction step for introducing a tension force in a direction close to each of the first tension material and the second tension material exposed in the void, and the tension force introduction step Later, tense force and introduced the first tension member and tension member connecting step for connecting the second tension member, characterized in that it has a.

In this invention, since the edge part side which the 1st tendon material and the 2nd tendon material mutually spaces apart is inserted so that it may not be exposed to an empty concrete member, the side which the 1st tendon material and the 2nd tendon material mutually spaces apart It can suppress that a deterioration factor penetrate | invades from the edge part.
Conventionally, when a tension material such as a shear steel rod is provided as a tension material on the bridge slab, a notch is formed in the floor slab where the end of the tension material is exposed, so durability considering the notch However, in the present invention, since it is not necessary to form such a notch, it is possible to reliably ensure durability.

Moreover, in the tension | tensile_strength introduction method of the tension material which concerns on this invention, after the said tension material connection process, concrete is laid in the said empty part, and the connection part of the said 1st tension material and the said 2nd tension material is made into the said concrete. You may have the empty part concrete placement process embedded in.
By setting it as such a structure, since the whole of each 1st tension material and 2nd tension material is embed | buried under concrete, deterioration of a 1st tension material and a 2nd tension material can be prevented.

Moreover, in the tension | tensile_strength introduction method of the tension material which concerns on this invention, at the said tension material arrangement | positioning process, it temporarily connects with the connecting tool which connects the said 1st tension material and the said 2nd tension material in the said tension material connection process. Also good.
By setting it as such a structure, a 1st tension material and a 2nd tension material can be easily maintained in a coaxial state using the connection tool which connects a 1st tension material and a 2nd tension material. . In addition, the first tendon and the second tendon can be connected with high accuracy.

Moreover, in the tension | tensile_strength introduction | transduction method of the tension | tensile_strength material which concerns on this invention, the said tension | tensile_strength introduction | transduction process pinches | interposes the attracting metal fittings fixed to each of the said 1st tension material and the said 2nd tension material from the mutually spaced-apart side, Tensile force is applied to the first tendon and the second tendon by pulling the attracting bracket fixed to the first tendon and the attracting bracket fixed to the second tendon. May be introduced.
By setting it as such a structure, tension | tensile_strength can be simultaneously introduced with respect to a 1st tension material and a 2nd tension material.

  According to this invention, it can suppress that a deterioration factor penetrate | invades from the edge part of a tendon.

It is a figure which shows an example of the concrete member by 1st Embodiment of this invention. It is a figure explaining a tension material arrangement | positioning process and an empty part concrete member formation process. It is a figure explaining a tension power introduction process. It is a figure explaining the tension | tensile_strength introduction process and tension material connection process following FIG. It is a figure explaining the empty concrete member formation process by 2nd Embodiment of this invention.

(First embodiment)
Hereinafter, the tension | tensile_strength introduction method of the tension material by 1st Embodiment of this invention is demonstrated based on FIG. 1 thru | or FIG.
As shown in FIG. 1, the tension material 1 according to the first embodiment is a PC steel material or the like, embedded in a concrete member 2 constituting a beam material or the like, and introduces prestress into the concrete member 2.
The tendon 1 has a first tendon 3 and a second tendon 4 arranged coaxially with axial end faces facing each other. The first tension member 3 is provided with a first fixing tool 6 that fixes to the concrete 5 of the concrete member 2 in the vicinity of the end portion (referred to as the first end portion 3 a) on the side away from the second tension member 4. Yes. The second tension member 4 is provided with a second fixing tool 7 for fixing to the concrete 5 of the concrete member 2 in the vicinity of the end portion (referred to as the second end portion 4 a) on the side away from the first tension material 3. .

The first tendon 3 and the second tendon 4 are connected to each other by a connector (connector) 8 such as a coupler in a state in which a tension force toward each adjacent side is introduced.
In the present embodiment, the tension force is introduced so that the first tension material 3 and the second tension material 4 are attracted to each other. For this reason, the first pulling metal 9 is fixed to the first tendon 3 on the side closer to the second tendon 4 than the first fixing tool 6. In addition, a second pulling metal fitting 10 is fixed to the second tendon member 4 on the side closer to the first tendon member 3 than the second fixing tool 7.
The first drawing metal 9 and the second drawing metal 10 are composed of, for example, bolts that are screwed into the first tensioning material 3 and the second tensioning material 4, and the first tensioning material 3 and the second tensioning material 3. Projecting radially outward from the outer peripheral surface of the tendon 4.
The first tension member 3, the second tension member 4, the first fixing tool 6, the second fixing tool 7, the connection tool 8, the first drawing metal fitting 9 and the second drawing metal fitting 10 are the concrete member 2. Is embedded in the concrete 5.

Next, a method for producing the concrete member 2 (a method for introducing a tension force of a tension material) will be described.
First, as shown in FIG. 2, the 1st tension material 3 and the 2nd tension material 4 are arrange | positioned inside the formwork (not shown) of the concrete member 2 (tensile material arrangement | positioning process).
The first tension member 3 is in a state in which the first fixing tool 6 and the first attracting metal fitting 9 are fixed, and the second tension material 4 is in a state in which the second fixing tool 7 and the second attracting metal fitting 10 are fixed. And
The first tendon members 3 and the second tendon members 4 are arranged so that the sides on which the first fixing tool 6 and the second fixing tool 7 are not attached are opposed to each other with a space therebetween.
The first tendon 3 and the second tendon 4 are temporarily connected by the connecting tool 8.

Subsequently, concrete is placed in the mold (empty concrete member forming step).
In the empty concrete member forming step, the first fixing member 6 and the first tension member 3 are closer to the first end 3a side than the first drawing metal fitting 9 and the second fixing member 7 and the second tension member 4 are disposed. The second end 4 a side of the second drawing metal 10 is embedded in the concrete 5, and the second tension is higher than the first drawing metal 9 and the first drawing metal 9 of the first tension member 3. The form 4 so that the material 4 side and the first tendon 3 side of the second pulling metal 10 and the second pulling metal 4 than the second pulling metal 10 are exposed without being embedded in the concrete 5. Concrete 5 is placed on the surface.
In the present embodiment, the first tensioning metal 9 and the first tensioning material 3 are closer to the second tensioning material 4 side than the first tensioning metal 9 and the second attraction metallization 10 and the second tensioning material 4. A mold for unboxing that forms an empty portion 51 for exposing these to the mold so that the first tension member 3 side of the second pulling metal fitting 10 is exposed without being embedded in the concrete 5. (Not shown) is provided and the concrete 5 is placed.
After placing the concrete 5, curing is performed for a predetermined period. The concrete member having the void 51 formed in this way is referred to as a void-containing concrete member 21.

Subsequently, as shown in FIG. 3 and FIG. 4, a tension force is introduced into the first tension material 3 and the second tension material 4 (a tension force introduction step).
The introduction of the tension force to the first tension material 3 and the second tension material 4 is performed from the empty space 51.
The sandwiching jack 11 disposed in the empty portion 51 simultaneously sandwiches the first attracting metal 9 fixed to the first tendon 3 and the second attracting metal 10 fixed to the second tendon 4, A tension force is introduced into the first tension member 3 and the second tension member 4 so that the first pulling bracket 9 and the second pulling bracket 10 are attracted to each other.

Then, the 1st tension material 3 and the 2nd tension material 4 are connected (tensile material connection process).
The connecting tool 8 that temporarily connects the first tendon 3 and the second tendon 4 is closed, and the first tendon 3 and the second tendon 4 are fully connected by the connector 8.
By doing in this way, the 1st tension material 3 and the 2nd tension material 4 are connected in the state into which the tension force was introduced.

Subsequently, as shown in FIG. 1, the concrete 5 is placed in the empty portion 51 (empty concrete placing step).
In the empty concrete placing step, the first tensioning metal 9 and the first tensioning material 3 are located closer to the second tensioning material 4 than the first tensioning metal 9, and the second tensioning metal 10 and the second tensioning metal 9. The first tendon 3 side of the material 4 with respect to the second drawing metal fitting 10 is embedded in the concrete 5.
After placing the concrete 5, curing is performed for a predetermined period.
By doing in this way, the concrete member 2 by which each of the 1st tension material 3 and the 2nd tension material 4 each was embed | buried under the concrete 5 is manufactured.

Next, the operation and effect of the tension material introducing method of the tension material according to the first embodiment will be described with reference to the drawings.
In the method for introducing the tension of the tension material of the prestressed concrete according to the first embodiment described above, the first tension material 3 and the second tension material 4 that are separated from each other are embedded in the concrete. It can suppress that a deterioration factor penetrate | invades from the 1st end part 3a and the 2nd end part 4a of the 2nd tension material 4. FIG.
Moreover, since the whole of the 1st tension material 3 and the 2nd tension material 4 is embed | buried under the concrete 5 by performing an empty part concrete placement process after a tension material connection process, the 1st tension material 3 and the 1st 2 Deterioration of the tendon 4 can be prevented.
Conventionally, when a tension material such as a shear steel rod is provided as a tension material on the bridge slab, a notch is formed in the floor slab where the end of the tension material is exposed, so durability considering the notch However, in this embodiment, since it is not necessary to form such a notch, durability can be ensured reliably.

Moreover, in the tension material arrangement | positioning process, the 1st tension material 3 and the 2nd tension material 4 are temporarily connected by the connecting tool 8 which connects in the tension material connection process, and the 1st tension material 3 and the 2nd tension material 4 The first tendon member 3 and the second tendon member 4 can be easily maintained in the coaxial state by using the connection tool 8 for connecting the two. Moreover, the 1st tension material 3 and the 2nd tension material 4 can be connected accurately.
Further, in the tension introducing step, the first drawing metal 9 and the second drawing metal 10 are sandwiched from the side away from each other, and the first drawing metal 9 and the second drawing metal 10 are mutually connected. By introducing a tension force to the first tension material 3 and the second tension material 4 so as to be drawn, a tension force can be simultaneously introduced to the first tension material 3 and the second tension material 4.

(Second Embodiment)
Next, the second embodiment will be described with reference to the accompanying drawings. However, the same or similar members and parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. A different configuration will be described.
As shown in FIG. 5, in the tension force introducing method according to the second embodiment, the empty concrete member 21 </ b> B is formed by joining a plurality of precast concrete members 22 in the empty concrete member forming step. In the second embodiment, the empty portion-containing concrete member 21 </ b> B includes two precast concrete members 22 and 22 in which cutout portions 52 and 52 corresponding to substantially half of the empty portion 51 are formed. The empty concrete member 21 </ b> B is arranged and joined so that the two precast concrete members 22 abut each other in the extending direction of the first tendon 3 and the second tendon 4. It is formed by that.

One of the two precast concrete members 22 is manufactured in a state of being embedded so that the side of the first tendon 3 that is separated from the second tendon 4 is not exposed, and the other is the first of the second tendon 4. It is manufactured in a state where it is buried so that the side away from the tendon 3 is not exposed. And if the two precast concrete members 22 and 22 are joined, the 1st tension material 3 and the 2nd tension material 4 will be arrange | positioned coaxially.
Note that one of the two precast concrete members 22 and 22 is manufactured in a state in which a joint such as a coupler that can join the side of the first tendon 3 away from the second tendon 4 is embedded, and the other is the second tendon. A joint such as a coupler that can join the side of the tendon 4 that is separated from the first tendon 3 is embedded, and the first tendon 3 and the second tendon 4 are joined to these joints. It may be configured.

  In the tension force introducing method according to the second embodiment, the same effect as that of the first embodiment is achieved, and the empty concrete member 21B is composed of the precast concrete member 22. Can be produced.

As mentioned above, although embodiment of the tension | tensile_strength introduction method of the tension material by this invention was described, this invention is not limited to said embodiment, It can change suitably in the range which does not deviate from the meaning.
For example, in the above embodiment, after the tension material connecting step, the empty concrete placing step of placing the concrete 5 in the empty portion 51 is performed, but when the empty portion 51 may be left, the empty portion It is not necessary to perform the concrete placing process.

Moreover, in said embodiment, although the 1st tension material 3 and the 2nd tension material 4 are temporarily connected by the connection tool 8 in the tension material arrangement | positioning process, you may temporarily connect by members other than the connection tool 8. FIG. And it is not necessary to temporarily connect the 1st tension material 3 and the 2nd tension material 4 in the tension material arrangement | positioning process.
Moreover, in said embodiment, tension | tensile_strength is introduce | transduced to the 1st tension | tensile_strength material 3 and the 2nd tension | tensile_strength material 4 so that the 1st draw-in metal fitting 9 and the 2nd draw-in metal fitting may be drawn in in the tension | tensile_strength introduction process. However, the method of introducing tension into the first tendon 3 and the second tendon 4 may be other than the above.

DESCRIPTION OF SYMBOLS 1 Tension material 2 Concrete member 3 1st tension material 3a 1st edge part 4 2nd tension material 4a 2nd edge part 5 Concrete 6 1st fixing tool 7 2nd fixing tool 8 Connection tool (connection part)
9 First metal fitting 10 Second metal fitting 21, 21B Empty concrete member 22 Precast concrete member 51 Empty part

Claims (4)

In the tension introduction method of the tension material that introduces the tension force to the tension material of the pre-stress concrete,
A tension material arrangement step of arranging the first tension material and the second tension material constituting the tension material opposite to each other and coaxially arranging the tension material,
The first tendon and the second tendon are inserted and fixed so as not to be exposed, and the opposite ends of the first tendon and the second tendon are exposed. An empty concrete member forming step for forming an empty concrete material member having an empty space;
After the empty concrete member forming step, a tension force introducing step for introducing tension forces in directions close to each of the first tension material and the second tension material exposed in the empty portion;
A tension material introduction method for a tension material, comprising: a tension material connection step for connecting the first tension material into which the tension force is introduced and the second tension material after the tension force introduction step.   After the tension material connecting step, there is an empty concrete placing step in which concrete is placed in the empty portion and a connection portion between the first tension material and the second tension material is buried in the concrete. The tension | tensile_strength introduction method of the tension material of Claim 1 to do.   The tendon material according to claim 1 or 2, wherein in the tendon material arranging step, the first tendon material and the second tendon material are temporarily connected by a connecting tool for connecting in the tendon material connecting step. How to introduce tension.   In the tension force introducing step, the attracting metal fitting fixed to the first tendon material and the second tendon material is sandwiched from the side away from each other, and the attracting metal fitting fixed to the first tendon material; The tension force is introduced into the first tension material and the second tension material so as to draw the drawing metal fitting fixed to the second tension material together. The tension | tensile_strength introduction method of the tension material as described in one.

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