JP2001132165A - Fixing tool for pc cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing tool for a PC cable allowing the inserting work and the stretching/fixing work of the PC cable and the grout injecting work simply and safely. SOLUTION: This fixing tool is provided with a tapered male cone 40 holding the PC cable, a female cone 50 having an insertion hole matched with the outer shape of the male cone 40, and a buried member 30 buried in concrete to transfer the fixing load of the PC cable to the concrete. A pair of cylinder sections 31 are crossed into a nearly X-shape to integrally form the buried member 30. Each cylinder section 31 has a storage section 51 of the male cone 40 on one end side and a fitting port 33 of a sheath 70 on the other end side. A grout cap 60 can be fitted to the opening of the cylinder section 31 by screwing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for tensioning a PC cable which is mainly used for introducing prestress in a circumferential direction of a circular concrete structure such as a shield tunnel or a tank.

[0002]

2. Description of the Related Art Generally, the lining of a shield tunnel is
As shown in FIG. 5, an arc-shaped concrete segment 80 produced at a factory is assembled into a tubular shape in a pit. The assembled segment 80 must be firmly integrated so as to withstand the earth pressure and water pressure acting on the tunnel, and as a means of introducing prestress in the circumferential direction of the segment 80 is performed.

[0003] Prestress is introduced by inserting a PC cable into a sheath 70 embedded in the circumferential direction of each segment 80 in advance and tightening. At that time, as shown in FIG. 6, the PC cable goes around the lining body, and both ends intersect at the inner periphery of the segment, and the notch 91 formed at the inner periphery of the segment.
Pull out each end from the jack and tighten with jack 90. Also,
The fixing device 10 is embedded in the segment 80, and the end of the PC cable inserted into the fixing device 10 is fixed using a male cone (wedge) or the like. The following technology is known as the fixing device 10 for fixing a PC cable as described above.

(A) Conventional technique 1: JP-A-10-46991, "Segment for shield tunnel lining body and method for introducing prestress of shield tunnel lining body" As shown in FIG. It comprises a pair of cylindrical portions 100 integrated in an X shape, and a male cone 110 that is inserted into one end of the cylindrical portion and fixes a PC cable. The fixing tool is buried in the segment in advance, a PC cable is inserted into the tubular portion 100 later, the male cone 110 is set, and tension and fixing are performed using a jack and a bending chair.

(B) Prior art 2: Fixing tool (ring anchor) of FIG. 8 This fixing tool 10 is also common to the fixing tool of prior art 1 in that a pair of cylindrical portions 100 are arranged in parallel and integrated. . The difference is
While the fixing device of the prior art 1 is previously embedded in the segment, the fixing device performs tensioning of the PC cable and fixing by the male cone 110 in the large cutout 120 formed in the segment 80. Post-cast concrete in the notch. The holes formed on both sides of the notch 120 are grout injection holes 130.

[0006]

However, the above prior art has the following problems. In the case of “Prior art 1”, the cylindrical portion itself is a storage portion for the male cone, and the storage portion for the male cone needs to be processed into a tapered shape. But very difficult. Further, when the strand is tensioned by installing the male cone, there is a concern that rust is generated on the tapered surface in the cylindrical portion where the male cone is installed, and the fixing cannot be performed normally. further,
When grouting is performed by installing a grout cap in the opening of the cylindrical portion, grout is injected into the entire cable only from the gap between the male cones, so that the injection workability is poor. The grout cap has a structure in which the grout cap is fixed to the fixing tool with a plurality of small bolts, and the work of tightening the bolts in the cutouts in the segments is extremely complicated.

In the case of "Prior Art 2", the problem as in "Prior Art 1" does not occur. However, a large notch for accommodating the entire fixing device is required, and the reinforcing bar is cut at that portion, which sometimes causes a structural defect.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a PC cable fixing device which can easily and safely perform a PC cable insertion operation, a tension / fixing operation, and a grout injection operation.

[0009]

According to the present invention, the above object is achieved by using a female cone in addition to a male cone and a buried member having a cylindrical portion integrated in an X shape.

That is, the fixing device of the present invention comprises a tapered male cone for holding a PC cable, a female cone having an insertion hole adapted to the external shape of the male cone, and a fixing load of the PC cable embedded in concrete. A buried member for transmitting to concrete. The buried members are integrally formed in parallel so that a pair of cylindrical portions intersect substantially in an X shape. Each of the cylindrical portions has a female cone storage portion on one end side and a sheath mounting port on the other end side.

In the conventional fixing device, since the cylindrical portion has the function of the female cone, the male cone storage portion needs to be formed in a tapered shape, so that a sufficient inner diameter cannot be obtained. In the fixing device of the present invention, since the female cone is a member independent of the cylindrical portion, the female cone housing portion in the cylindrical portion does not need to be formed in a tapered shape, and can be formed to have a uniform inner diameter in the axial direction. Therefore, the inner diameter of the cylindrical portion can be made large, and the insertability of the PC cable can be improved.

Further, in this fixing device, a male cone and a female cone are installed just before the tension after inserting the PC cable.
Unstable fixing of the male cone due to the generation of rust can be avoided.

Further, by applying the following constitutions individually or in combination to the fixing device, the workability of the PC cable insertion operation, the tension / fixing operation or the grout injection operation can be further improved.

[0014] A groove is provided on the inner periphery of the storage section in which the female cone is disposed, through which grout passes. With this groove, a gap can be formed between the female cone and its storage portion, and grout can be easily injected through the gap.

[0015] A grout cap screwed through a packing is provided on the opening side of the storage portion, and the grout cap is provided with a grout injection hole. By using such a grout cap, mounting can be performed easily and quickly even in a small cutout in the segment, and the grout cap can be securely fixed to a degree that can withstand the pressure of the grout. In addition, the entire area held by the male cone, which is very important for the quality of the PC cable, is reliably filled with grout and the rust prevention effect is also improved, so reliability is improved. Furthermore, if the cross-sectional shape of the grout cap is polygonal, the cap can be easily held and can be easily screwed.

The mounting hole of the sheath is formed into a tapered shape in which the inner diameter on the opening side is large and the inner diameter on the back side is small, and the end of the sheath mounting hole on the back side stops the end of the sheath. A step is formed. With such a mounting hole, without using a special sheath joint,
Simple and reliable connection can be achieved simply by inserting the sheath directly.
At this time, the insertion length of the sheath does not vary due to the step that stops. Further, when the fixing device into which the sheath is inserted is embedded in concrete (segment), water can be stopped so that the concrete does not turn inside the fixing body.

Each cylindrical portion is configured to have a certain bending. When prestress is introduced into a circular structure such as a tunnel or a thin concrete member having a floor slab structure, the end of the PC cable needs to be drawn out to the inner periphery of a circular structure (eg, a segment for a shield tunnel). At that time, a notch is provided on the inner periphery of the segment, and the opening side of the fixing tool is put into the notch. If the cylindrical portion is bent, the size of the notch can be reduced because the opening side of the fixing tool is close to the inner peripheral surface of the segment. For this reason, the cutting points of the reinforcing bars in the segment can be minimized, and a decrease in segment strength can be suppressed.

A groove for passing grout is provided on the inner periphery of the storage section in which the female cone is disposed, and this groove is located outside the bend of the fixing device. When applying a fixing device in which each cylindrical portion has a constant bend to the segment for the shield tunnel, the PC cable is inserted along the outside of the bend of the cylindrical portion. At this time, the female cone storage portion in each cylindrical portion has a step where the inner part of the female cone is abutted, so that if the end of the PC cable hits this step, it cannot be inserted smoothly. . Therefore, if the grouting groove is formed outside the bend on the inner peripheral surface of the cylindrical portion, the end of the PC cable can be easily inserted without hitting the step.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Here, a case where prestress is introduced in the circumferential direction of the shield tunnel segment is taken as an example.

FIG. 1 is a partial sectional view showing a state in which a PC cable is fixed by the fixing device of the present invention, FIG. 2 (A) is a sectional view taken along line AA of FIG. 1, and FIG. 2 (B) is a sectional view taken along line BB of FIG.

The fixing device 10 includes a buried member 30 buried in concrete and transmitting the fixing load of the PC cable 20 to the concrete, a male cone 40 having a tapered shape for gripping the PC cable 20, and an outer shape of the male cone 40. And a female cone 50 having an insertion hole adapted to the above. FIG. 1 also shows a grout cap 60 attached to the opening of the embedded member 30 and a sheath 70 inserted into the fixing device 10.

(Buried Member) First, the buried member 30 will be described with reference to FIGS. FIG. 3 is a partial sectional view of the buried member,
4A is a sectional view taken along line CC in FIG. 3, and FIG. 4B is a sectional view taken along line DD in FIG. The buried member 30 is made of cast iron and has a pair of cylindrical portions 31.
Are integrated in parallel so as to intersect substantially in an X shape. Each of the cylindrical portions 31 is formed with a certain bend, a storage portion 32 of the female cone 50 is formed at one end, and a mounting hole 33 of a sheath which is thinner at one end than the one end is formed. The storage portions 32 in the respective cylindrical portions are arranged so as to open in opposite directions.

The female cone storage section 32 is a cylindrical hole having a uniform inner diameter in the axial direction. The opening side of the storage section 32 is a step.
The inner portion of the grout cap mounting portion 35, which has a larger inner diameter via 34, is formed with four inner peripheral protrusions 36 on the inner periphery of the mounting portion 35 (FIGS. 4B and 1). Notches are formed between the inner peripheral projections 36, and a pair of opposing members is a wide notch 37, and the other pair is a narrow notch 38. Also, the end of the storage portion 32 on the back side is an intermediate portion 30 having a smaller inner diameter via a step 39.
Continues to 0. The step 39 serves as a stop for the female cone 50.

A groove 301 for injecting grout was formed in the inner peripheral surface of the storage section 32. In this example, as shown in FIG. 4A, three grooves 301 are formed at substantially 90 ° intervals, and one of them is formed on the inner peripheral surface of the storage portion at a position outside the bending of the cylindrical member. . One end of each groove 301 faces the grout cap mounting portion 35, and the other end goes around the depth of the step 39 and faces the intermediate portion 300. The transition point 302 from the other end of the groove 301 to the intermediate portion 300 is preferably formed of a curved surface. This is because the PC cable 20 can be smoothly inserted along the curved surface.

On the other hand, the sheath mounting hole 33 is formed in a tapered shape in which the opening side is wide and the back side is narrow. The inside diameter on the opening side is larger than the outside diameter of the sheath 70, and the inside diameter on the back side is slightly smaller than the outside diameter of the sheath 70. Further, a step 303 is formed on the inner side of the sheath mounting hole 33 so as to stop the end of the sheath. Therefore, the sheath can be easily and reliably connected by inserting the sheath into the mounting hole 33 and pushing the sheath until the end of the sheath hits the step 303.

(Male Cone) The male cone 40 is composed of a plurality of metal pieces that become conical when combined (FIG. 1).
In this example, a male cone 40 composed of three metal pieces was used. Further, a grip hole for the PC cable is formed in the axial direction of the male cone 40. The inner peripheral surface of the holding hole is roughened to increase friction with the PC cable 20. Further, a circumferential groove is formed on the large-diameter side of the outer peripheral surface of the male cone.
The metal pieces can be prevented from coming apart when the ring 41 is fitted and the PC cable 20 is gripped.

(Female Cone) The female cone 50 is a cylindrical body having a tapered insertion hole 51 formed therein (FIG. 1). Its outer diameter is substantially equal to the inner diameter of the female cone storage portion 32 in the cylindrical portion 31.
And the tapered insertion hole 51 has a shape and dimensions adapted to the external shape of the male cone 40, wedges the fitted male cone 40,
Tensioned with female corn 50 acting as wedge catch
The fixing of the PC cable 20 is performed.

(Grout Cap) Grout Cap 60
Is attached to the opening of the cylindrical portion 31 and serves as a spout for filling grout into the fixing device and the sheath (FIG. 1). A grout injection hole 61 is formed at one end, and an intermediate portion 62 is formed.
Is formed in the shape of a rectangular prism having a rectangular cross section (FIG. 2B), and at the other end side, the outer diameter changes from a large diameter portion 63 to a small diameter portion 64 to form a step 65. A pair of outer projections 66 are formed on the outer periphery of the small-diameter portion 64 so as to fit into the opening of the cylindrical portion 31. The outer peripheral projection 66 has a narrow width in the circumferential direction. When the outer peripheral projection 66 is aligned with the wide notch 37 (FIG. 4B) of the storage section opening, and the grout cap 60 is pushed in from the opening of the cylindrical section 31 and rotated, the outer peripheral projection 66 becomes the inner peripheral projection of the storage section opening.
36 (FIG. 4B), the grout cap 60 is
Attached to.

A ring-shaped packing 67 is fitted on the outer periphery of the small diameter portion 64. Thus, when the grout cap 60 is attached to the opening of the cylindrical portion 31, the packing 67 is interposed between the grout cap 60 and the opening of the cylindrical portion, and leakage of the grout can be prevented.

Further, since the middle portion 62 of the grout cap is formed in a prismatic shape, it can be easily grasped by hand, and can be easily screwed into the cylindrical portion 31.

The material of the grout cap 60 is not particularly limited. In this example, inexpensive polyethylene which is easy to mold was used.

(PC cable) Fixed by the fixing device of the present invention
PC cable 20 (Fig. 1) is used for PC strand or unbonded PC.
Strands can be used. In this example, a coating 22 was formed on a PC steel wire 21 in which a plurality of strands were twisted, and an unbonded PC strand filled with grease between the coating 22 and the PC steel wire 21 was used. The end of the unbonded PC strand that is in tension is stripped of the coating 22 to expose the PC steel wire 21.

(Sheath) The end of the sheath 70 is inserted into the sheath mounting hole 33 of the embedding member, and is preliminarily embedded in the segment together with the embedding member 30 (FIG. 1). In this example, a corrugated pipe made of polyethylene was used.

(Fixing Procedure) The fixing device of the present invention is used as follows. (1) The sheath 70 is inserted into the sheath mounting hole 33 of the fixing device, and placed in a mold in that state, and concrete is cast to form an arc-shaped segment. Therefore, the embedded member is embedded in the segment. The opening of the cylindrical portion of the embedded member faces a notch 81 formed in the segment 80 (FIG. 6).

(2) The segments are assembled to form a cylinder (FIG. 5).

(3) From the opening of one cylindrical portion 31 to the PC cable 2
Insert 0. The inserted PC cable 20 proceeds along the outside of the bend in the inner peripheral surface of the cylindrical portion, and is introduced into the sheath. The end of the PC cable 20 that has passed through the sheath and around the wrapper is drawn out from the opening of the other cylindrical portion 31 (FIGS. 5 and 6).

(4) The female cones 50 are fitted around the outer ends of both cable ends, and the female cones 50 are inserted into the storage portions 32 of the respective cylindrical portions. Furthermore, the male cone 40 is also attached to the outer circumference of the PC cable,
The O-ring 41 stops each metal piece so that it does not come apart (FIG. 1).

(5) Tension the end of the PC cable with the jack 90 (FIGS. 5 and 6). 5 and 6, only one jack is shown, and the other one is omitted. In this tension state, the male cone 40 is inserted into the insertion hole of the female cone 50, and the end of the PC cable 20 is fixed. Here, each end of the PC cable 20 is tensioned by two jacks 90 arranged on both sides of the fixing device. However, one end is fixed in the fixing device, and only the other end is tensioned by the jack 90. May be.

(6) Remove the jack 90 and connect the PC cable 20
Is cut off, and a grout cap 60 is attached to one of the cylindrical openings (FIG. 1). Grout is injected from the injection hole 61 of the cap. The injected grout fills the inside of the cylindrical part through the groove on the inner circumference of the cylindrical part, and further, the sheath 70 and PC
The space between the cable 20 is also filled. Then, the grout is discharged from the other cylindrical portion opening.

(7) Thereafter, concrete is filled in the notches 81 of the segments to complete the lining (FIGS. 5 and 6).

It should be noted that the fixing device for a PC cable of the present invention is not limited to the illustrated example described above, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0042]

As described above, according to the fixing device of the present invention, the following effects can be obtained. Therefore, it can be effectively used as a fixing device for a circular structure, an intermediate tension fixing device for members, and a fixing device for a general prestressed concrete structure.

By making the female cone a member independent of the cylindrical portion, the female cone housing portion in the cylindrical portion does not need to be formed in a tapered shape, and can be formed in the axial direction to have a uniform and large inner diameter. Cable insertability can be improved.

Since the male cone and the female cone are installed immediately before the tension after the insertion of the PC cable, unstable fixing of the male cone due to the generation of rust can be avoided.

A groove is formed on the inner periphery of the storage section where the female cone is arranged to allow grout to pass therethrough, thereby forming a gap between the female cone and the storage section, and grout is injected through this gap. It can be done easily.

By providing a grout cap which is screwed through the packing on the opening side of the storage portion, the grout cap can be easily and quickly mounted even in a small notch in the segment, and can be securely fixed to the extent that it can withstand the pressure of the grout. In addition, the entire area where the PC cable is held by the male cone can be reliably filled with grout, and the rust prevention effect is also improved. Furthermore, if the cross-sectional shape of the grout cap is polygonal,
The cap is easy to hold and can be easily screwed on.

The mounting hole of the sheath is tapered with a large diameter at the opening side, and a step is formed at the back side to stop the end of the sheath, so that the sheath is directly inserted without using a special sheath joint. Can be easily and reliably connected.

By providing a bend in each cylindrical portion, the notch of the segment where the opening side of the cylindrical portion is exposed can be reduced,
The number of cuts of the reinforcing bars in the segment can be minimized, and a decrease in segment strength can be suppressed.

By providing a bend in each cylindrical portion and providing a grouting groove on the inner periphery of the storage portion in which the female cone is arranged, the end of the PC cable hits a step which stops the female cone. This prevents the PC cable from being inserted.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a state in which a PC cable is fixed by a fixing device of the present invention.

2 (A) is a sectional view taken along line AA of FIG. 1, and FIG. 2 (B) is FIG.
It is BB sectional drawing of.

FIG. 3 is a partial sectional view of an embedded member in the fixing device of the present invention.

4A is a sectional view taken along the line CC in FIG. 3, and FIG.
3 is a sectional view taken along the line DD in FIG.

FIG. 5 is an explanatory diagram when introducing a prestress into a shield tunnel lining body with a PC cable.

6 (A) is an enlarged view of the vicinity of the fixing device of FIG. 5, and FIG. 6 (B) is an enlarged view of the vicinity of the fixing device as viewed from the inner periphery of the segment.

7A and 7B show a conventional fixing device, wherein FIG. 7A is a perspective view as viewed from an opening side, and FIG. 7B is a partial sectional view of EE.

FIG. 8 is an explanatory diagram illustrating an example of use of a fixing device having a configuration different from that of FIG. 7;

[Explanation of symbols]

 10 Fixing device 20 Cable 21 Steel wire 22 Insulation 30 Buried member 31 Cylindrical part 32 Female cone storage part 33 Sheath mounting hole 34 Step 35 Grout cap mounting part 36 Inner circumference projection 37 Wide notch 38 Narrow notch 39 Step 40 Male cone 41 O Ring 50 Female cone 51 Insertion hole 60 Grout cap 61 Grout injection hole 62 Middle part 63 Large diameter part 64 Small diameter part 65 Step 66 Outer peripheral protrusion 67 Packing 70 Sheath 80 Segment 81 Notch 90 Jack 91 Notch 100 Cylindrical part 110 Male cone 120 Notch 130 Grout injection hole 300 Middle part 301 Groove 302 Transition point 303 Step

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Taiji Mikami 1-3-12 Moto-Akasaka, Minato-ku, Tokyo Sumitomo Electric Industries, Ltd. Tokyo Head Office (72) Inventor Yoichi Takayama Kitaichi Kunyo, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Shinichiro Kumagai 13-13 Arakicho, Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd. (72) Inventor Shinichi Kondo 13-Arakicho, Shinjuku-ku, Tokyo No.4 Sumitomo Construction Co., Ltd. (72) Inventor Masashi Kaneko 13-4 Arakicho, Shinjuku-ku, Tokyo Sumitomo Construction Co., Ltd. F-term (reference) 2D047 AB02 2D055 BB01 GC03 2E164 AA02 DA01 DA12 DA22

Claims (8)

[Claims] A male cone having a tapered shape for gripping a PC cable; a female cone having an insertion hole adapted to the external shape of the male cone; and a buried member buried in the concrete to transmit a fixing load of the PC cable to the concrete. The embedded member is integrally formed in parallel so that a pair of cylindrical portions intersect substantially in an X shape. Each of the cylindrical portions has a female cone storage portion on one end side, and the other end. A fixing device for a PC cable, characterized by having a sheath mounting port on the side. 2. The fixing device for a PC cable according to claim 1, wherein the accommodation portion of the female cone in the cylindrical portion is formed to have a uniform inner diameter in the axial direction. 3. The fixing device for a PC cable according to claim 1, wherein a groove for allowing grout to pass therethrough is provided on an inner periphery of the storage portion in which the female cone is arranged. 4. A grout cap which is screwed through a packing on the opening side of the storage portion, wherein the grout cap has a grout injection hole.
The fixing device for a PC cable according to 1. 5. The fixing device for a PC cable according to claim 4, wherein the grout cap has a polygonal cross-sectional shape. 6. The mounting hole of the sheath is formed into a tapered shape in which the inside diameter on the opening side is large and the inside diameter on the back side is small, and the end on the back side of the sheath mounting hole is stopped by the end of the sheath. The fixing device for a PC cable according to claim 1, wherein a step is formed. 7. The fixing device for a PC cable according to claim 1, wherein each cylindrical portion is formed to have a predetermined bending. 8. The PC according to claim 7, further comprising a groove for allowing a grout to pass through an inner periphery of the storage section in which the female cone is disposed, wherein the groove is outside a bend of the fixing device. Fixing tool for cable.