JP3439264B2 - Fixing body for PC structure, method for constructing PC structure, and PC structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PC (prestressed concrete) structure, a method for constructing the structure, and a fixing tool such as a fixing body used for the construction.

[0002]

2. Description of the Related Art Inserting a PC steel material into concrete,
As a method of tension-fixing, a method of fixing one end of PC steel material and tensioning it from the other end, and fixing the tensioned end with a fixing body is well known.

Since tensioning and fixing at the other end requires a fairly large and long working space, the present inventors have previously proposed a method of reducing this space by using a curved guide.
Proposed as No. 5-17342.

[0004]

[Patent Document 5] FIG.
-17342 shows a construction method using the curved guide 15 and by this, the volume of the working notch portion 16 for tensioning the drawn PC steel material formed by using the conventional steel and wooden formwork Was reduced.

However, as shown in the schematic view of FIG. 5, due to the lengthening of the structure and the like in recent years, the place where the fixing member 1 is used is more likely to be installed inside the outer wall end of the structure, that is, in the middle of the concrete slab floor. Further reduction of the above space is required.

This is because the slab streak in the concrete slab floor is often cut by the notch 16 formed by using a formwork, which may cause a structural defect, and the PC steel material is tightly fixed. This is because there is a problem in work such as the need to backfill the notch.

Also in the proposed method using the curved guide, the fixing body 1 for tensioning and fixing the PC steel material has the same axial direction as the main axial direction of the PC steel material P as in the conventional construction method, and the concrete 9 is preliminarily used. It is buried inside.

Therefore, the tension of the PC steel material P is grasped by the jack 17 by grasping the PC steel material end portion P2 projecting outward from the fixed body with the notch 16 provided outside the fixed body as the working space. Therefore, even if the bending guide 15 is used to deflect the pulling direction of the jack, the length of the cutout portion 16 is still long and the obstacle due to the cutout portion 16 cannot be sufficiently eliminated.

[0009]

The present invention has been made in order to solve the above problems. The first characteristic of the present invention is that a PC steel material embedded in concrete and strained is as follows. It is to have a fixed end.

In the conical portion on the outer end side of the through hole of the fixing body in which the PC steel material is inserted, it is fixed by a wedge fitted between the conical portion and the PC steel material, and has a curved portion on the inner end side of the through hole. That is, the axial direction of the PC steel material fixed end that is curved by the tubular portion is deviated from the main axis direction of the embedded and strained PC steel material. Due to the deflection in the axial direction of the PC steel material in the fixing body, it is sufficient to form a short working hole having a small diameter instead of forming the conventional cutout portion.

The second feature is a method for constructing a PC structure having the above-mentioned fixed end portions, in which the fixing member is embedded in concrete, the outer end peripheral surface portion of the identification fixing member is
After attaching a pipe surrounding the outer end face and placing concrete except on the outer end of the fixing body surrounded by the pipe, by a working hole on the outer end face of the fixing body formed by the pipe,
It is to tighten and fix the inserted PC steel.

The third feature is to provide a fixing member used as a means for deflecting the axial direction of the fixed end of the PC steel material from the main axial direction of the PC steel material which is buried and strained as described above.

In this fixing member, the outer end side of the through hole provided in the central portion of the fixing member has a conical shape, the inner end side has a cylindrical shape, and the cylindrical portion is curved so that the inner end thereof has an axial direction. Is formed so as to be deflected with respect to the axial direction of the conical portion.

In addition to the above-mentioned three characteristics, more specific constitutions are added to each of them in order to more reliably bring out the effects of the characteristics. For the reality of this addition,
An example will be described.

[0015]

EXAMPLE FIG. 1 is a schematic side view illustrating a method for constructing a fixed end of a PC structure in an example. P is P
C steel material, P1 is its unbonded coating, and P2 is the fixed side end of PC steel material. S is a coated slab muscle, S1 is an upper slab muscle, S2 is a lower slab muscle, and S3 is an auxiliary muscle.

FIGS. 2A and 2B are a front view and a partially longitudinal side view of the fixing body 1 shown in FIG. 1, which shows a rectangular outer end side having a through hole 2 through which a PC steel material P to be used can be inserted. It is a casting fixing body. The PC steel material P used in the examples is a steel stranded wire having a diameter of 15.2 mm, and the rectangular portion on the outer end side of the fixing body 1 is 14
The size was 0 mm x 70 mm, and the bearing surface was sufficient to prevent bending when introducing tension. A conical portion 3 is provided on the outer end side of the through hole 2 and is formed in a tubular shape following the conical portion 3 on the inner end side. A curved portion 4 having a radius R of 150 mm is formed in the tubular portion. It is provided.

By this curved portion 4, the axial direction of the conical portion 3 on the outer end side of the through hole 2 and the axial direction of the cylindrical inner end are deflected by 30 °. A wedge 10 is inserted between the conical portion 3 and the PC steel material P.

A pipe 6 made of plastic or iron is detachably attached to the outer peripheral surface portion 5 of the fixing body 1 by a pressing plate 7, for example. Of course, this binding may be performed by other methods such as binding or using a bonding agent. Also, the pipe does not necessarily have to be circular in cross section. The prepared tools including the above-mentioned members are temporarily fixed to a predetermined position by, for example, being attached to the slab muscle S that has been arranged.

After that, concrete 9 is poured until the slab concrete top 8 is reached. This casting is performed in the entire peripheral region except the portion 11 on the outer end surface of the fixing body 1 surrounded by the pipe 6. When the concrete 9 is solidified, the portion 11 becomes a working hole 11 on the outer end surface of the fixing body 1 . Normally, after forming the working hole 11, the pipe 6 is pulled out, but in a special case, it may be buried.

From the working hole 11 thus formed,
After the concrete-developed concrete end portion P2 on the fixed side of the PC steel material is grasped and pulled by a dedicated jack (not shown), tension is applied to the PC steel material P. After giving a predetermined tension, to secure pushing the wedge 10 in the conical portion 3 of the constant adherend 1 in that state. This push-in operates the fixing ram built into the tip of the dedicated jack by hydraulic pressure,
It is carried out without losing the tension applied to the PC steel material P, but of course other methods may be used.

Thus, when the PC steel material P is tensioned and fixed, the working hole 11 is backfilled with concrete, and the construction is completed. In Examples one end of the general PC steel takes place is a fixed end and the other end tension, it has been described as comprising a fixed end, if you particularly necessary, also be allowed to deflect the PC steel inside the fixed end it can.

According to the above embodiment, the constant adherend 1 and the pipe 6 which articulates on the upper end peripheral surface portion is shorter operation hole 11 of the minimum required less is formed, a frame type as in the prior art It is not necessary to provide a working space with the large cutout used. Therefore, the obstacle due to the cutting of the slab muscle for forming the cutout portion is eliminated, and the work for backfilling the work hole is simpler than the work for backfilling the cutout portion.

FIG. 3 is a side sectional schematic view for explaining another embodiment of the fixing member 1. The through hole 2 in the central portion is an outer member 12 mainly including a portion forming the conical portion 3 on the outer end side.
And an inner member mainly having a tubular shape provided with a curved portion 4 on the inner end side
Both members 13 and 13 are combined by a fitting portion 14 to be formed.

The invention as described above, in the fixing end a PC steel, the most significant feature is that to deflect the axial direction thereof, a cylindrical curvature deflection is provided on the constant adherend 1 4 and this configuration is important.

[0025] Therefore, the constant adherend 1 must be manufactured in those with sufficient strength to withstand the tension on the deflection direction of the PC steel P by the steel casting and the like, constant adherend 1, the size of the through-holes 2 Needless to say, specific numerical values such as the bending radius of the bending portion 4 and the deflection angle need to be appropriately selected and determined according to the specifications of the PC structure.

Further, as shown in the above-mentioned another embodiment, if the fixing member 1 is constructed by combining a plurality of fixing members 1 such as the outer member 12 and the inner member 13, each member can be easily manufactured. Also, for example, for one type of outer member 12 of the same shape and size,
Various inner members 13 having different radii of the curved portion 4 and different lengths of the tubular portion 13
In advance, both members can be appropriately combined and used according to the specifications of the PC structure, which can contribute to shortening the construction period, saving materials, and the like.

[0027]

As described in each of the above-mentioned items, according to the present invention, it is not necessary to form a cutout portion using a mold when concrete is conventionally cast, and the presence of the cutout portion is eliminated. Various obstacles are eliminated. Moreover, even in the members to be prepared and the construction process, there is no difference from the conventional method except that it relates to the constitution of the fixing member of the present invention.
It is easy to implement and suitable for actual construction.

[Brief description of drawings]

FIG. 1 is a schematic side view illustrating a method of constructing a fixed end of a PC structure in an example.

2A and 2B show the structure of the fixing member of FIG. 1, in which A is a front view and B is a partially longitudinal side view.

FIG. 3 is a schematic cross-sectional side view for explaining another embodiment of the fixing member.

FIG. 4 is a side sectional view showing a construction method of a fixed end portion proposed by Japanese Patent Publication No. 5-17342.

FIG. 5 is a schematic view from the upper surface for explaining the fixed end portion of the PC steel material of the PC structure.

[Explanation of symbols]

P PC steel Unbonded coating of P1 PC steel P2 PC Steel material fixed side end S slab muscle S1 Slab upper muscle S2 Slab inferior muscle S3 Slab auxiliary muscle 1 fixing body 2 Through hole of fixing body 3 Conical part of through hole 4 Curved part of through hole 5 Outer peripheral surface of the fixing body 6 tubular 7 Presser plate 8 Slab concrete crown 9 concrete 10 wedges 11 A part surrounded by a tubular body. Working hole 12 External member of fixing body 13 Inner member of fixing body 14 Fitting part of outer member and inner member 15 Curved guide 16 Notch 17 jack

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-5968 (JP, A) JP-A-63-233149 (JP, A) Fukukaihei 6-16553 (JP, U) Japanese Patent Publication 5- 17342 (JP, B2) JP-B-44-26216 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) E04G 21/12 104 E04B 5/43 E04C 5/08 E04C 5/12

Claims (5)

(57) [Claims] 1. A through hole through which an end of PC steel is inserted is provided.
The fixing member for a PC structure, wherein the through hole has a conical portion that expands toward one end side, and
And a tubular portion having the same diameter continuing from the portion toward the other end side, and a wedge for fixing the PC steel material is fitted into the conical portion.
The tubular portion has a curved portion that is curved in the tubular portion.
A fixing body for a PC structure, characterized by having . 2. A fixing body, outer member and the cylindrical portion PC structure according to claim 1, characterized by being formed by combining the inner member mainly composed of mainly a conical portion use fuser. 3. A fixing member according to claim 1 or 2, wherein the <br/> pipe surrounding the PC steel with is fitted into the outer end of the fixing member, the wedge being inserted into the conical portion of the fixing member A fixing device for a PC structure, comprising: 4. The fixing member according to claim 1, wherein P is formed in the through hole.
Insert the end of C steel material and place this fixing body at a predetermined position
A step of, fitting a pipe surrounding the PC steel on the outer end side of the fixing member, a step of Da設concrete except for the pipe, from the work Goana formed by the pipe, nervous and P C steel , the construction method of the PC structure, characterized in that it comprises a step of fixing by fitting interpolated wedge in a circular conical portion of the fixing member. 5. A PC which is embedded and tensioned in concrete.
At least one fixed end of the steel material, claim 1 or 2
A PC structure characterized by being fixed by the fixing body of .