JPH0327165Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a water-stop structure for the anchorage of unbonded PC steel in a prestressed concrete structure in which prestress is introduced by unbonded PC steel.

Unbonded PC steel is one of the tendons for prestressed concrete structures. This unbonded PC steel material is made by applying lubricant such as grease around the prestressed steel strands and covering this with a plastic sheath, so there is no need to grout the gap between the prestressing steel material insertion hole and the prestressing steel material. Therefore, it has the advantage of being able to save labor in construction. In addition, when introducing prestress into a concrete structure using such unbonded PC steel materials, for example, one end of the unbonded PC steel material is fixed with a crimp grip, etc., and the coating is removed from the other end.
A method is used in which the PC steel strands are tensed using tension jacks, etc., and then fixed with a fixing device via a bearing plate, and then the fixing device is covered with concrete.

However, in the past, the unbonded PC steel material was used as a tendon to join the end faces of a concrete structure, for example, a divided box formed in a cylindrical shape with a top plate, a bottom plate, and both side plates, to each other. When the box is used in an assembled underground water storage tank made of multiple tension members, water may leak into the prestressing steel material insertion hole from the joints of the concrete covering the fixing device or the joints between split boxes. The water penetrates into the area where the coating of the unbonded PC steel material is removed, and from there it also penetrates into the inside of the unbonded PC steel material, causing the PC to deteriorate.
There were problems such as the wire rusting more than the steel.

This idea was proposed based on the above-mentioned circumstances, and by applying a filler that adheres to the unbonded PC steel material to the part where the coating of the unbonded PC steel material has been removed, it is possible to fill the inside of the PC steel material insertion hole. To provide a water-stopping structure for an unbonded PC steel fixing part, which prevents water from penetrating into the coating of the unbonded PC steel even if water penetrates into the surface of the unbonded PC steel, and allows easy construction of a filler.

This invention will be explained below with reference to the drawings.

1 and 2 show a first embodiment in which this invention is applied to an assembled underground water tank.
First, let me explain about this prefabricated underground water tank.
This prefabricated underground water tank is constructed by joining together the end faces 1d of a divided box 1 formed into a cylindrical shape by an arc-shaped top plate part 1a, a bottom plate part 1b, and both side plates 1c, 1c, as well as opening an opening. The split box 1 and the end board 2 are covered with an end plate 2 and are constructed by integrating the split box 1 and the end board 2 with a plurality of unbonded PC steel members 3 arranged in the connection direction of the split box 1.

Moreover, this unbonded PC steel material 3 is inserted into the PC steel material insertion hole 4 as shown in FIG.
One end (the right end in the figure) is crimped with a crimp grip 5 and is supported by a bearing plate 8 within a grout hole 6 via a guide member 7, and the other end is stripped of its covering, a fixing device 9 is attached, and the grout hole is crimped with a crimping grip 5. 10 and is supported by a bearing plate 11. Note that the fixing tool 9
is composed of a female cone 12 and a male cone 13, and the inner peripheral surface of the female cone 12 and the male cone 13
The PC steel stranded wire 3a of the unbonded PC steel material 3 is sandwiched between the outer peripheral surface of the PC steel member 3 and the PC steel wire 3a of the unbonded PC steel material 3, and is locked by friction.

The water-stopping structure of the unbonded PC steel fixing part according to this invention is such that the PC steel insertion hole 4 is formed to have a larger diameter from the end 4a on the fixing tool 9 side toward the covering part 3b of the unbonded PC steel 3. A backup material 15 made of an elastic material such as liquid-tight rubber is provided in the annular gap G between the inner wall 14a of the large diameter portion 14 and the covering portion 3b of the unbonded prestressing steel material 3. A through hole 16 is formed that communicates the large diameter portion 14 with the outside, and the unbonded PC steel material is inserted from the through hole 16 into the large diameter portion 14 between the unbonded PC steel material 3 and the bearing plate 11. 3 is coated with an adhesive filler 17.

The large diameter portion 14 of the prestressed steel material insertion hole 4 is formed to penetrate through the end plate 2 in the thickness direction, and the joint portion between the divided box 1 and the end plate 2 is connected to the prestressed steel material insertion hole 4 and its large diameter portion 14. It is the boundary between

Further, the back-up material 15 is provided at the boundary between the PC steel material insertion hole 4 and its large diameter portion 14, and the filler material 17 filled in the large diameter portion 14 is
This is provided to prevent leakage into the steel material insertion hole 4.

Further, the through hole 16 is for inserting a filler 17 into the large diameter portion 14, and is formed above and below the bearing plate 11 with the unbonded PC steel material 3 sandwiched therebetween.

The filler 17 is for preventing water that has penetrated into the prestressing steel material insertion hole 4 from penetrating into the covering portion of the unbonded prestressed steel material 3, and is made of, for example, resin, mortar, etc. .

It goes without saying that the grout holes 6 and 10 are filled with concrete 18 and the like after the tensioning work of the unbonded PC steel material 3 is completed to cover the fixing portions at both ends of the PC steel material 3. Preferably, the ends of the fixing tool 9 and the uncoated PC steel material 3 may be coated with a resin or the like, and then concrete or the like may be filled into the grout hole 10.

Next, the method for applying the filler 17 in the large diameter portion 14 will be explained. Before tensioning the unbonded PC steel material 3, filler material 17 is placed in the annular gap G between the inner wall 14a of the large diameter portion 14 and the unbonded PC steel material 3. A backup material 15 is inserted in advance, and after tensioning the PC steel material, a filler 17 is injected into the large diameter portion 14 from the through hole 16 on the lower side of the bearing pressure plate 11. Fill the hole 16 until it overflows. At this time, even if the backup material 15 is pushed by the filler 17, it is supported by the boundary between the large diameter portion 14 and the prestressing steel material insertion hole 4, and the backup material 15 pushes the inside of the prestressing steel material insertion hole 4. Since the filler 17 does not leak, the filler 17
is filled only into the large diameter portion 14, which is a small volume between the backup material 15 and the bearing pressure plate 11. Therefore, the amount of filler 17 is small and the filling operation can be easily performed.

Further, the backup material 15 is normally inserted from the end of the unbonded PC steel material 3 into the annular gap G between the inner wall surface 14a of the large diameter portion 14 and the covering portion 3b of the unbonded PC steel material 3. In this first embodiment, the PC steel insertion hole of the end plate 2 is the large diameter part 14, so when assembling the underground water tank, it can be inserted from the end face side (right rule in Figure 2). , since the inserted point is the boundary between the PC steel material insertion hole 4 and the large diameter part 14, the backup material 15
can be easily installed.

According to the water-stop structure configured as described above, even if water seeps into the prestressing steel material insertion hole 4, the portion where the coating is peeled off will be covered with the filler material 17. Therefore, water never enters the inside of the coating of the unbonded PC steel material 3 from the part where the coating is removed. Furthermore, since the amount of filler 17 to be injected is very small, the filling operation can be easily and quickly performed, and costs can be reduced.

Further, FIG. 3 shows a second embodiment of this invention, in which the PC steel material insertion hole of the end plate 2 is made into a stepped hole 19, and the embodiment configured in this way is also different from the previous embodiment. Similar effects can be obtained, and even when the thickness of the end plate 2 is increased, the amount of filler 17 can be reduced, and the filling work can be shortened when the plate thickness is thick.

Next, a third embodiment of this invention will be described with reference to FIG. This is carried out when each PC steel material insertion hole 4 of the divided box 1 and the end plate 2 is sufficiently large to insert the backup material 15, and the filler material 17 is inserted into the through hole 16. A backup material 15 having enough elasticity to not shift when injected from the inside is pushed up to the covering portion 3b of the unbonded prestressed steel material 3. In such a case, it is not particularly necessary to provide the large diameter portion 14 for inserting the backup material 15, and the same effects as in the embodiment described above can be achieved.

As explained above, this invention involves removing the coating from the end of the unbonded PC steel material inserted into the PC steel material insertion hole, and attaching the fixing device to this end via the bearing plate. ,
A back-up material is provided between the inner wall of the prestressing steel material insertion hole and the covering portion of the end of the unbonded prestressing steel material, a through hole is formed in the bearing plate to communicate the insertion hole with the outside, and Since the structure is such that a filler having adhesiveness to the unbonded PC steel material is applied between the backup material and the bearing plate in the insertion hole from one of the holes,
Even if water seeps into the PC steel material insertion hole from the outside,
The filler prevents water from entering the coating of the unbonded PC steel material, and only a small amount of filler is needed, so the filling process can be done easily and in a short time, further reducing costs. When planned, it produces a great effect.

[Brief explanation of the drawing]

1 and 2 are a schematic perspective view and a sectional view of an assembled underground water tank to which the water stop structure of the first embodiment of this invention is applied, and FIG. 3 is a sectional view showing the second embodiment of this invention. 4 are sectional views showing a third embodiment of this invention. 1... Divided box, 2... End plate, 3... Unbonded PC steel material, 3a... PC steel stranded wire, 3b... Covering part, 4... PC steel material insertion hole, 4a... End part, 9...
... Fixing tool, 10... Grout hole, 11... Bearing plate, 14... Large diameter portion, 15... Backup material, 16... Through hole, 17... Filling material.

Claims (1)

[Scope of utility model registration request] In the unbonded PC steel material fixing section, in which the coating of the end of the unbonded PC steel material inserted into the PC steel material insertion hole is peeled off, and a fixing device is attached to this end via a bearing plate, the inner wall of the PC steel material insertion hole and the A backup material is provided between the end of the unbonded PC steel material and the covering part, a through hole is formed in the bearing plate to communicate the insertion hole with the outside, and one of the through holes is inserted into the insertion hole. A water-stopping structure for an unbonded PC steel fixing part, wherein a filler having adhesiveness to the unbonded PC steel is applied between the back-up material and the bearing plate.