JP3645557B2 - PC steel wire tension release device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a PC steel wire tension releasing device, and more particularly, to an improvement in a PC steel wire tension holding unit that maintains a state where a necessary tension is applied to a concrete structure.
[0002]
[Prior art]
Conventionally, there is prestressed concrete that applies compressive stress to a concrete structure. As this is well known, after pulling a high strength steel material called PC steel material and applying tension (this operation is called tension), it is fixed to a concrete structure using a PC steel wire tension holding member. A compressive force is applied to the concrete structure by the PC steel material to be restored.
[0003]
This PC steel wire tension holding member is arranged in a connecting hole portion of a PC steel wire formed in a concrete structure, and a bearing plate provided with a communication hole through which the PC steel wire is inserted, and a longitudinal direction of the center portion A wedge having a saw-tooth-like meshing tooth for gripping a PC steel wire, and a wedge shaped like a truncated cone in external view divided into three in the longitudinal direction, and a conical shape engaged with the wedge These are provided with a sleeve provided with an engagement hole, and are held in tension by a wedge mechanism composed of the above-described wedge and sleeve (see, for example, Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-079700 (page 2, FIG. 1)
[0005]
[Problems to be solved by the invention]
By the way, the above-described PC steel wire tension holding member may be used for a temporary concrete structure including a temporary bridge. In this case, at the end of the temporary installation, the PC steel wire tension retaining member attached to the temporary concrete structure should be removed and stored, so that it can be used again for other temporary concrete structures that meet the purpose. Efficient.
[0006]
Moreover, apart from the reuse of the PC steel wire tension holding member described above, there is a case where the tension end timing is missed during the tension work of the PC steel wire, resulting in over-tensioning. In that case, it is necessary to slightly adjust the tension of the PC steel wire in an overstressed state so as to obtain a desired normal tension.
[0007]
When such a PC steel wire tension holding member is reused or over tension is corrected, the first thing that must be done is to open the wedge wedged on the sleeve.
[0008]
However, it is not easy to fully wedge the sleeve and release the wedged wedge. That is, the tensioned PC steel wire is pulled with a hydraulic jack, the wedge is separated from the sleeve, and the wedge is not engaged again.
[0009]
For example, it is possible to insert a shim for the amount of elongation of the PC steel wire between the bearing plate and the sleeve during the tension work of the PC steel wire, and to remove the shim when opening it. However, as an actual problem, if there is an elongation strain as much as 1000 mm, it is necessary to prepare a huge shim for that amount, and to perform an attaching / detaching operation. Further, if the huge shim is attached to the concrete structure, naturally, a huge protrusion is formed. That is, in the structure using the conventional PC steel wire tension holding member, it is practically impossible to release the tension state.
[0010]
Therefore, the present invention provides a PC steel wire tension releasing device that can release a tensioned PC steel wire and can easily perform reuse of a PC steel wire tension holding member, correction of excessive tension, and the like. The purpose is to do.
[0011]
[Means for Solving the Problems]
In order to solve the above-described problems, the PC steel wire tension releasing device according to the present invention has the following technical means.
That is, the PC steel wire tension release device according to claim 1 is provided with a communication plate that is provided in a communication hole portion of a PC steel wire formed in a concrete structure and has a communication hole through which the PC steel wire is inserted. And a sleeve configured to be in wedge engagement with a wedge so as to sandwich the PC steel wire extended through the pressure bearing plate portion, the tensioned state from the bottom surface of the sleeve A shim member having a required thickness longer than the distance to the bottom surface of the wedge is interposed, and the shim member released from the sandwiched state by tensioning the PC steel wire with a tension jack that takes a reaction force on the bearing plate. A convex portion that detaches and further loosens the tension of the PC steel wire and supports the sleeve on the bearing plate so as to abut against the bottom surface of the wedge to restrict the movement of the wedge and release the wedge engagement On the bearing plate Characterized in that the openable configure state of PC steel wire.
According to a second aspect of the present invention, there is provided the PC steel wire tension releasing device according to the first aspect, wherein the bearing plate portion includes a planar bearing plate provided with the communication hole, a flange formed in the middle portion, and a flange lower surface thereof A hollow cylindrical tubular member removably inserted in the communication hole so as to contact the upper surface of the bearing plate, and the upper part from the flange is the convex part, and the shim member is It is characterized by being interposed between the upper surface of the flange and the sleeve.
According to a third aspect of the present invention, there is provided the PC steel wire tension releasing device according to the second aspect, wherein the cylindrical member is divided in a longitudinal direction with an axis as a boundary.
According to a fourth aspect of the present invention, there is provided the PC steel wire tension releasing device according to the first aspect, wherein the bearing plate portion is arranged so as to be concentric with the planar bearing plate provided with the communication hole and the communication hole. A hollow cylindrical collar, and
The collar is the convex part, and the shim member is interposed between the upper surface of the bearing plate and the sleeve.
A PC steel wire tension releasing device according to claim 5 is the pressure bearing plate according to claim 1, wherein the bearing plate portion is a projecting portion formed by projecting and forming the vicinity of the communication hole in a cylindrical shape, The shim member is interposed between the upper surface of the bearing plate and the sleeve.
A PC steel wire tension releasing device according to a sixth aspect of the present invention is the PC steel wire tension releasing device according to any one of the first to fifth aspects, wherein the shim member is formed so as to straddle a chuck portion including the wedge and the sleeve. A jack locking body provided with a possible opening, the bottom surface of the jack locking body is brought into contact with the bearing plate, the tension jack is attached to the top surface, and the tension jack is attached to the bearing plate. It is made to support.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings. 1 to 7 show the first embodiment, FIG. 8 shows the second embodiment, and FIG. 9 shows the third embodiment.
[0013]
(Embodiment 1)
As shown in FIG. 1, the PC steel wire tension releasing device according to the first embodiment includes a support plate 1, a shim member 2, a chuck 3, and a jack locking body 4. .
[0014]
The bearing plate 1 is composed of a bearing plate 11 and a cylindrical member 12.
[0015]
The support plate 11 is a well-known one having a communication hole 111 through which a PC steel wire is inserted at the center and having a substantially disk shape in appearance, and a connection hole for the PC steel wire W formed in the concrete structure A. It arrange | positions so that the part a1 may be plugged up.
[0016]
The cylindrical member 12 has a hollow cylindrical shape that is divided into two in the longitudinal direction with a shaft center provided with a first hole 122 into which a flange 121 is formed in the middle and the PC steel wire W is inserted. With the flange 121 as a boundary, the cylindrical upper portion 123 has a required outer diameter capable of coming into contact with the bottom surface of the wedge 31, and the cylindrical lower portion 124 has a communication hole 111 provided in the above-described bearing plate 11. The lower part 124 is fitted in the communication hole 111 of the bearing plate 11.
[0017]
As shown in FIG. 2, the shim member 2 has a required thickness that is curved at one end so as to contact the peripheral surface of the upper portion 123 of the cylindrical member 12 and is substantially equal to the height of the upper portion 123 of the cylindrical member 12. A pair of block shapes are provided, and are arranged so as to face each other with the upper portion 123 of the cylindrical member 12 interposed therebetween.
[0018]
The chuck portion 3 includes a wedge 31, a sleeve 32, a lid member 33, and a compression spring 34.
[0019]
The wedge 31 is provided with a meshing hole 311 formed with sawtooth-shaped meshing teeth for gripping the PC steel wire W in the longitudinal direction of the central portion, and is substantially truncated in an external view. It has a well-known structure with a shape.
[0020]
The sleeve 32 has a hollow shaft shape provided with a conical engagement hole 321 that engages with the wedge 31, and the wedge 31 is housed in the engagement hole 321. The sleeve 32 is disposed on the shim member 2, and the wedge 31 moves deeply into the engagement hole 321 by the force that the tensioned PC steel wire W tries to return to the original position. It is designed to bite and tension the steel wire W circumferential surface.
[0021]
The relationship between the sleeve 32, the wedge 31, the PC steel wire W, the shim member 2, and the thicknesses (dimensions) of each of them will be described. As shown in FIG. When the engagement hole 321 moves deeply and stops (PC steel wire W holding state), when the distance from the bottom surface of the sleeve 32 to the bottom surface of the wedge 31 is L1, and the thickness of the shim member 2 is L2, L2 > L1 is established, and when the shim member 2 is pulled out, a gap is generated between the sleeve 32 and the wedge 31 by an amount corresponding to subtracting L1 from L2, and the wedge engagement is released. .
[0022]
The lid member 33 has a disk shape with a PC steel wire W inserted in the center thereof, and is screwed into a step portion 322 formed on the upper portion of the sleeve 32.
[0023]
The compression spring 34 is a compression spring 34 having a required spring constant stretched between the lid member 33 and the wedge 31. The wedge 31 is always urged against the sleeve 32, so that the wedge 31 can be removed from the tension work. When switching to engagement, the movement of the wedge 31 is minimized.
[0024]
The jack locking body 4 is used when the tension is released from the state in which the wedge 31 is wedge-engaged with the sleeve 32 and the tension is maintained (the state in which the compressive force is applied to the concrete structure A). The hole 41 through which the PC steel wire W can be inserted has a cylindrical shape provided in the center of the upper surface portion, and the lower end thereof has a required size through which the shim member 2 and the cylindrical member 12 divided into two can be inserted. An opening 42 is provided, and a confirmation hole 43 for visually observing the movement of the sleeve 32 when tension is released is provided so as to face the midway portion of the side surface.
[0025]
Next, a series of opening operations using the PC steel wire W tension releasing device according to the first embodiment configured as described above will be described.
[0026]
As shown in FIG. 4, in order to release the tension of the PC steel wire W from the state in which the PC steel wire W is held in tension by the wedge mechanism constituted by the wedge 31 and the sleeve 32, first, the bearing plate 11 is released. The jack locking body 4 is put on the chuck portion 3 so as to abut against the chuck portion (see FIG. 1).
[0027]
Subsequently, the tension jack J is set on the upper portion of the jack locking body 4, and the PC steel wire W is pulled as in the normal tension work to lift the chuck portion 3 (see FIG. 5).
Whether or not the chuck portion 3 has been lifted is confirmed by looking through the confirmation hole 43 of the jack locking body 4. When the chuck portion 3 is lifted, the movement of the tension jack J is stopped and the shim member 2 is stopped via the opening 42. Is pulled out and removed (see FIG. 6).
[0028]
When the operation of pulling out the shim member 2 is finished, the tension of the PC steel wire W is gradually loosened, and the bottom surface of the sleeve 32 is brought into contact with the surface of the flange 121 of the tubular member 12. At this time, since the shim member 2 is removed, the sleeve 32 moves by the distance L2 illustrated in FIG. 1, but the wedge 31 moves only by the distance L1, and therefore the wedge is moved by the difference (L2−L1). A gap is formed between 31 and the sleeve 32. And the wedge 31 which has gripped the PC steel wire W can move in the direction perpendicular to the tension direction by the gap, and the grip of the PC steel wire W of the wedge 31 is released, and the through state is established. (See FIG. 7).
An upper portion 123 from the flange 121 of the cylindrical member 12 is a convex portion that abuts against the bottom surface of the wedge 31 and restricts the movement of the wedge 31.
[0029]
Thus, by releasing from the tension holding state, each member described above can be reused, and over-tension can be easily corrected.
The tension work opposite to the above-described tension release work is performed by setting the tension jack J on the upper portion of the chuck portion 3 without using the jack locking body 4 and obtaining a desired compressive force on the concrete structure A. Pull the PC steel wire W up to that point. Next, after the shim member 2 is inserted between the sleeve 32 and the cylindrical member 12, the tensioning operation is terminated and the tensioned state is maintained.
[0030]
Furthermore, the attachment procedure of the PC steel wire tension releasing device of the present embodiment is first performed using the jack locking body 4 with respect to the conventional one in which the tension state is already maintained only by the chuck portion 3. The cylindrical member 12 divided into two is set in the communication hole 111 through the opening 42, and then the shim member 2 is set in the cylindrical member 12 and the jack is removed to complete the process. As described above, since the cylindrical member 12 is also divided into at least two parts, it is possible to easily cope with a conventional member in which the tension state is already maintained.
[0031]
(Embodiment 2)
The PC steel wire tension releasing device according to the second embodiment is configured to be placed on the bearing plate 11 in place of the cylindrical member 12 with the flange 121 illustrated in the first embodiment instead of a simple collar 12b. It is a thing. When the shim member 2 is removed in a tension state, the collar 12b becomes a convex portion so that the wedge engagement is released, and the other constituent members are the same as those in the first embodiment. The same reference numerals as those in the first embodiment are given, and detailed description thereof is omitted.
[0032]
(Embodiment 3)
The PC steel wire tension releasing device according to the third embodiment is provided with a convex portion 11c on the bearing plate 11b instead of the tubular member 12 of the first embodiment and the collar 12b of the second embodiment. With this configuration, the cylindrical member 12 and the collar 12b can be provided separately. Since the other constituent members are the same as those in the first embodiment, the same reference numerals as those in the first embodiment are given, and the detailed description thereof is omitted.
[0033]
As mentioned above, although the PC steel wire tension release apparatus concerning this embodiment was demonstrated, embodiment mentioned above shows an example of suitable embodiment of this invention, and this invention is not limited to it. Various modifications can be made without departing from the scope of the invention.
[0034]
【The invention's effect】
According to the present invention, by pulling the tension-maintained PC steel wire, and then removing the clamped shim member and releasing the tension, the amount of movement of the wedge is regulated by the convex portion, and the wedge and the sleeve Since the PC steel wire in a tension state can be opened between the two, the PC steel wire tension holding member can be easily reused or over-tensed can be corrected.
Further, since the cylindrical member is also divided into at least two parts and set in the communication hole, it is possible to easily cope with a conventional member in which the tension state is already maintained in the chuck portion.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view of a PC steel wire tension releasing device according to a first embodiment.
2 is a cross-sectional view taken along the line (A)-(A) in FIG.
FIG. 3 is an exploded perspective view of the same.
FIG. 4 is a longitudinal front view of the PC steel wire tension releasing device in the tension holding state.
FIG. 5 is a longitudinal front view of the PC steel wire tension releasing device during the tension releasing operation.
FIG. 6 is a longitudinal front view of the PC steel wire tension releasing device showing the detaching operation of the shim member following FIG. 5;
FIG. 7 is a longitudinal sectional front view of the PC steel wire tension releasing device showing a state in which the shim member is completely detached, following FIG. 6;
FIG. 8 is a longitudinal front view of the PC steel wire tension releasing device according to the second embodiment.
FIG. 9 is a longitudinal front view of a PC steel wire tension releasing device according to a third embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Supporting plate part 11 Supporting plate 12 Cylindrical member 123 Upper part (convex part)
2 Shim member 3 Chuck part 31 Wedge 32 Sleeve 4 Jack locking body 42 Opening part 43 Confirmation hole 12b Collar (convex part)
11c Convex part J Tension jack A Concrete structure W PC steel wire

Claims (6)

A bearing plate provided with a communication hole that is disposed in a connecting hole portion of the PC steel wire formed in the concrete structure and through which the PC steel wire is inserted;
Between the wedge and the sleeve configured to be wedge-engaged so as to sandwich the PC steel wire extended through the bearing plate,
While interposing a shim member having a required thickness longer than the distance from the bottom surface of the sleeve to the bottom surface of the wedge in a tension state,
Detach the shim member released from the sandwiched state by tensioning the PC steel wire with a tension jack that takes reaction force on the bearing plate.
Further, when the tension of the PC steel wire is relaxed and the sleeve is supported by the bearing plate, the convex portion that abuts the bottom surface of the wedge and restricts the movement of the wedge to release the wedge engagement is provided. A PC steel wire tension releasing device, which is provided on the pressure plate portion and is configured to be capable of opening a tensioned PC steel wire. The bearing plate is
A planar bearing plate provided with the communication hole;
A hollow cylindrical tubular member that is detachably inserted into the communication hole so that a flange is formed in the middle portion, and the lower surface of the flange contacts the upper surface of the bearing plate;
Consists of
2. The PC steel wire tension releasing device according to claim 1, wherein the convex portion is formed above the flange, and the shim member is interposed between the upper surface of the flange and the sleeve. The PC steel wire tension releasing device according to claim 2, wherein the cylindrical member is divided in a longitudinal direction with an axis as a boundary. The bearing plate is
A planar bearing plate provided with the communication hole;
A hollow cylindrical collar disposed so as to be concentric with the communication hole;
Consists of
2. The PC steel wire tension releasing device according to claim 1, wherein the collar is the convex portion, and the shim member is interposed between the upper surface of the bearing plate and the sleeve. 3. The pressure-bearing plate portion is a pressure-bearing plate that is formed in a cylindrical shape in the vicinity of the communication hole so as to form the convex portion, and
2. The PC steel wire tension releasing device according to claim 1, wherein the shim member is interposed between the upper surface of the bearing plate and the sleeve. A jack locking body that is formed so as to straddle a chuck portion that includes the wedge and the sleeve and that has an opening through which the shim member can be removed, and the bottom surface of the jack locking body is 6. The PC steel wire tension releasing device according to claim 1, wherein the tension jack is attached to a top surface of the pressure plate portion, and the tension jack is supported by the supporting pressure plate portion. .

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