JPS5821859Y2 - P/C concrete tension material tension fixing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a P-C concrete tendon tension fixing device.

Generally, when constructing PC concrete, an end fixing device using a cone that wedges the ends of PC strands is used.

When using this type of device to fix the ends of tendons such as P-C strands, the tendons inserted into the concrete structure are passed through the tendon insertion holes in the cone, and one end of the tendon insertion holes is inserted into the concrete structure. The tension material is preliminarily fixed by pushing a plurality of wedges into the tapered wedge-fitting portion formed in the tension material, and then the ends of the tension material are pulled with a tension jack to apply prestress to the tension material. .

Therefore, by pulling the tension material with a tension jack, the pre-fixed wedge must be pulled out to a certain extent to release the fixation, and when the tension by the tension jack is released, the tension material returns and the wedge is reattached. It is necessary for the tendon to be drawn into the tapered wedge-fitting part and fixed, and it is desirable that there is little return of the tendon at that time.
Furthermore, when the wedge is drawn in, each of the multiple parts needs to be drawn in uniformly.

In order to solve this problem, conventionally, for example, a plate has been used, and the removal of the wedge during tensioning with a tensioning jack has been kept to the minimum necessary.

However, with conventional equipment, it is not possible to completely prevent the tension material from returning after tensioning, and for this reason, heavy tensioning is performed in anticipation of the tension material returning in advance.
In this case, there were variations in the tension return for each wedge, and there was a drawback that uniform tension could not be obtained.

In view of the above-mentioned points, the present invention allows the tension material to be almost completely fixed by the wedge after pre-fixing, after tensioning the tension material with a tension jack and before releasing the tension by the tension jack, Minimize the return
Alternatively, the purpose is to provide a P-C concrete tendon end fixing device that can almost completely prevent return, and its gist is that the tendon inserted into the concrete structure is inserted into the concrete structure, and one end of the tendon is fixed. a pressure plate through which the tension material can freely pass through an end face of a fixing cone into which a fixing wedge for sandwiching a tension material is inserted into a shaped wedge-fitting portion and abutting on the fixing wedge; and a tensioning jack for tensioning the tension material. and,
a jack chair for supporting the reaction force of the jack on the peripheral edge of the fixing cone, a gap portion from which the fixing wedge can be freely extracted is provided on the surface of the jack air, and the pressing plate and the flat plate are provided in the gap portion. A P-shaped plate having a tension material through hole into which the tension material can be freely inserted, and a plate jack that is expanded by injection of pressure fluid and pushes out the pressure plate toward the fixing cone side are stacked together.
C. Contains tension anchoring equipment for concrete tension members.

Next, an example of implementation of the present invention will be described with reference to the drawings.

In the figure, 1 is a concrete structure, 2 is a sheath for inserting tendons, 3 is a bearing plate embedded in the end face of the concrete structure, and 4 is a tendon made of PC strands.

The tension member 4 includes a salt cone 6 having a large number of tension member insertion holes 5, a female cone 7 that is screwed onto the outer periphery of the salt cone 6 and abuts against the bearing pressure plate 3, and a A tapered wedge fitting portion 8 formed at the outer end of the tendon insertion hole 5
The end portion is fixed by a fixing device consisting of a half-split wedge 9 that is fitted into the tension member 4 and holds the tension member 4 therebetween.A tension fixing device that further tensions and fixes the tension member 4 includes a horizontal pressing plate 14;
It is comprised of a tensioning jack 10 that pulls the end of the tensioning material 4 and applies tension, and a plate jack 11 that pushes the wedge 9 into the wedge insertion part 8.

In the tension jack 10, the tip of the jack air 12 is engaged with the periphery of the tip of the salt cone 6, and the tension material 4 is inserted into the cut portion.

A wedge extraction cavity 13 is formed at the tip of the jack chair 12, and a horizontal pressing plate 14 and a plate jack 11 are inserted into the cavity 13.

The plate jack 11 is formed into a hollow flat plate shape, has a flexible curved portion 16 around its periphery, and has a bulging portion 18 that swells by pressurizing a pressure fluid into a hollow interior 17 on one side.

Tensor through holes 19 and 20 are formed in the central portion and on the front and back sides of the horizontal pressing plate 14 to correspond to the tendon through holes 5 of the salt cone 6.

By pressurizing the pressure fluid into the plate jack 11, the bulging portion 18 expands, pushing the lateral pressing plate 14 toward the wedge 9, and pushing the wedge 9 into the wedge fitting portion 8.

Further, by removing the pressure fluid from the plate jack 11, the bulging portion 18 returns to its original state, and the wedge 9 forms a gap necessary for releasing the tension material 4 from fixing.

Incidentally, the plate jack 11 may be provided with bulges 18 and 18 on both the front and back sides, as shown in FIG.

The P-C concrete tendon tension fixing device of the present invention is constructed as described above, and is provided with a wedge extraction cavity at the tip of the jack chair of the tension jack that is engaged with the outer peripheral edge of the cone. It has a flat plate shape and has a tension rod through hole into which a tension member can be freely inserted, and a plate jack that expands when pressure fluid is injected is inserted, and the wedge is pushed into the wedge insertion part of the cone using the plate jack. Therefore, it becomes possible to firmly bite the wedge that comes out by pulling the tension material with the tension jack after pre-fixing into the wedge insertion part before the tension is released by the tension jack.
Therefore, there is almost no return of tension when the tension is released, which eliminates variations in the tension force for each tendon, and allows the desired and accurate tension force to be obtained.

[Brief explanation of drawings]

The drawings show an example of the implementation of the present invention; FIG. 1 is a longitudinal sectional view, FIG. 2 is a partially enlarged sectional view showing the operating state, and FIG. 3 is a partially enlarged sectional view showing another embodiment of the plate jack. FIG. 1...Concrete structure, 4...Tension material, 5...Tension material insertion hole, 6...Salt cone, 8... Wedge insertion part, 9...Wedge,
10...Tension jack, 11...Plate jack, 12...Jack chair,
13...Wedge extraction gap, 14...Horizontal pressing plate, 18...Bulging part, 19°20...
...Tension material penetrates.

Claims (1)

[Scope of utility model registration request] The tension material is inserted into the concrete structure, and the tension material can freely pass through the end surface of an anchoring cone in which a fixing wedge that holds the tension material is inserted into a tapered wedge-fitting part at one end, and the tension material can freely pass through the fixing wedge. It has a pressing plate that comes into contact with it, a tension jack that pulls the tension material, and a jack chair that supports the reaction force of the jack on the peripheral edge of the fixing cone, and the jack chair has a surface on the fixing cone side. The fixing wedge is provided with a gap portion from which the fixing wedge can be freely pulled out, and in the gap portion, the pressing plate is formed into a flat plate-like shape, and has a tendon through hole through which the tension member can be freely inserted, and is expanded by injection of pressure fluid. and a plate jack for pushing out the pressing plate toward the fixing cone side.