JP4793955B1 - Anchor head and head back structure - Google Patents

Abstract

An object of the present invention is to provide a structure of the back of the head which can be easily visually checked without disassembling the back of the head for checking the soundness of the anchor end.
A support plate (anchor plate 3) for supporting a tension acting on a tension support member (11), an anchor head support member (2) mounted on the support plate (3), and a tension support member (tendon). 11) is provided with an anchor head (7) for adhering to the vicinity of the upper end of the anchor head, the anchor head support member (2) is filled with a corrosion inhibitor (for example, grease), and the viewing window (2w) is an anchor head support member. It is provided in (2).
[Selection] Figure 1

Description

  The present invention relates to a ground anchor, and more specifically, an anchor head and a head that apply tension to a tension support member (tendon) whose tip is fixed in the ground from the ground side and hold the upper end of the tendon. This relates to the back surface structure.

When the installation period of the ground anchor is prolonged, deterioration of the anchor head and the back of the head becomes a problem. When the anchor head and the back of the head deteriorate, the tendon on which the tension is applied is not sufficiently held on the ground side, and it may be difficult to maintain the supporting force of the ground anchor.
For example, a tendon made of stranded steel wire has corrosion resistance secured by a sheath at its free length, but the sheath is located above (in the direction away from the ground) the anchor plate that is the bearing member. Not present and tendon is exposed. Therefore, especially the tendon in the region immediately below the anchor head is likely to be corroded and deteriorated.
Therefore, if the field worker can visually check the state of the anchor head and the back of the head, particularly the state of the tendon immediately below the anchor head, it is determined whether the anchor head and the back of the head are deteriorated. It can be done easily.

However, with the conventional back structure of the anchor head, the state of the tendon directly under the anchor head cannot be confirmed unless the tension acting on the tendon is released and the anchor head and tendon are released. It was.
Therefore, even when a healthy anchor head and head rear structure that has not deteriorated are to be determined, it must be disassembled once to release the tension acting on the tendon. After the determination, it is necessary to apply tension to the tendon again with a jack or the like. Thus, disassembling a healthy anchor head and head back structure that has not deteriorated to release the tension acting on the tendon, and then applying the tension to the tendon again, requires a great deal of labor and cost. Will spend.
In order to reduce such labor and cost, there is a demand for a technique that can visually (or visually) observe the state of the anchor head and the back of the head, particularly the state of the tendon immediately below the anchor head. Not.

As another conventional technique, there is proposed an anchor head and head back mechanism that reliably exhibits water tightness regardless of the state of the sheath material when replacing the anchor head and head back parts. (See Patent Document 1).
According to the related art (Patent Document 1), when replacing parts of the anchor head and the back of the head, rainwater and spring water are prevented from entering the anchor head and the back of the head. It is possible to repair and prolong life reliably.
However, the technique of Patent Document 1 does not intend to visually recognize the state of the anchor head and the back of the head, particularly the state of the tendon immediately below the anchor head.

JP 2008-208623 A

  The present invention has been proposed in view of the above-mentioned problems of the prior art, and it is not necessary to disassemble the anchor head and the back of the head, and the state of the anchor head and the back of the head, particularly An object of the present invention is to provide an anchor head and a head back structure that can easily visually recognize (visually) the state of the tendon immediately below the anchor head.

  The anchor head and head back structure of the present invention includes a bearing plate (anchor plate 3) that supports tension acting on the tension supporting member (Tendon 11), and an anchor head supporting member placed on the bearing plate (3). (2) and an anchor head (7) that fixes the vicinity of the upper end of the tension support member (Tendon 11), and the anchor head support member (2) is filled with a corrosion inhibitor (for example, grease), A viewing window (2w) is provided on the anchor head support member (2).

  In the present invention, the tendon (11) is inserted into the anchor head support member (2), and a recess (step 2k) in which the anchor head (7) can be installed is formed above the anchor head support member (2). It is preferable to have a pipe made of a transparent material inserted into the anchor head support member (2) (FIGS. 1 to 5).

  Here, a flange portion (2f) is provided at the lower end of the anchor head support member (2), and the flange portion (2f) is attached to a pressure bearing plate (anchor plate 3). The anchor head support member (2) It is preferable that a water stop spacer (5) is provided in the lower part of the interior (FIG. 1).

A cap member (1) that covers the anchor head (7) and the free end (11e) of the tendon is provided, and the male screw portion (2st) formed on the upper end of the anchor head support member (2) and the cap member (1). It is preferable that the female thread portion (1st) formed at the lower end is screwed (FIG. 1).
Alternatively, the flange portion (2Af) is provided at the upper end of the anchor head support member (2A), the flange portion (1Af) is provided at the lower end of the cap member (1), and the flange portion (1Af) at the upper end of the anchor head support member (2A) ( 2Af) and the cap member (1) are preferably fastened with a lower end flange portion (1Af) with a fastening member (bolt BL2) (FIG. 5).

  According to the present invention having the above-described configuration, a mechanism for visually recognizing (viewing) the tendon immediately below the anchor head (7) is provided. Even if the tension acting on (11) is not released, the area just below the anchor head (7), where corrosion and deterioration are likely to proceed (since there is no sheath and the metal material constituting the tendon is exposed) It is possible to easily and accurately determine whether corrosion or deterioration has progressed by the mechanism for visually recognizing (observing) the tendon (11).

As a result, only the anchor head and the head back structure, which are judged to have deteriorated or corroded as a result of visual recognition (visual observation), are disassembled, the tension of the tendon (11) is released, and the necessary parts Can be replaced and repaired.
And, as a result of visual recognition (visual observation), when it is determined that deterioration or corrosion has not progressed, the anchor head and the head back structure are not disassembled, and it is not necessary to release the tension of tendon. It is possible to reduce the labor and cost required for such operations (disassembly operation of the anchor head and head back structure, tension release operation of tendon).

When the visual (visual) mechanism supports the tension acting on the tendon (11), the mechanism is made of a highly rigid material (for example, a metal such as iron) and is used for visual (visual). If a cylindrical member (4) made of a transparent material is inserted inside the window (2w), the state of tendon in the region immediately below the anchor head (7) is changed to the cylindrical member made of the transparent material ( 4) It can be visually recognized (viewed) through the window (2w) for viewing (viewing).
And since the tension | tensile_strength which acts on tendon (11) supports the part formed with a highly rigid material, it can maintain required intensity | strength as an anchor head and head back structure.
On the other hand, when the visual (visual) mechanism does not support the tension acting on the tendon (11), the mechanism is made of a transparent material, and the tendon state immediately below the anchor head (7) The mechanism can be seen through (viewed).

It is a longitudinal section showing a 1st embodiment of the present invention. It is a top view of a 1st embodiment. It is sectional drawing which shows the anchor head support member in 1st Embodiment. It is sectional drawing which shows the modification of an anchor head support member. It is a longitudinal cross-sectional view which shows 2nd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 and 2 show a first embodiment of the present invention.
In FIG. 1, an anchor plate 3 is installed on a frame 10, and a through hole 3 </ b> H is formed in the center of the anchor plate 3.
On the upper surface of the anchor plate 3, an anchor head support member 2 having a cylindrical shape as a whole is provided. A flange portion 2f (see FIG. 3) is formed at the lower end of the anchor head support member 2, and the flange 2f is attached to the anchor plate 3 by fastening bolts BL.

A water stop spacer 5 is interposed below the anchor head support member 2.
For example, a plurality of tendons 11 made of stranded steel wires pass through the through holes 3H of the anchor plate 3 and penetrate the water stop spacer 5, and the vicinity of the upper ends of the plurality of tendons 11 is fixed to the anchor head 7. is doing.
Although not clearly shown, the vicinity of the upper portion of the tendon 11 is fixed to the anchor head 7 using a conventionally known fixing device. The anchor head 7 is supported on the upper part of the anchor head support member 2 via a packing material 6.
Although not shown, the lower end of the tendon 11 is fixed in the ground, and a tensile force (tension) is applied to the tendon 11 by applying a tensile force to the upper end of the tendon 11 with a jack (not shown). Is working.

Although not clearly shown, the anchor head support member 2 is made of a material having rigidity capable of supporting the tension acting on the tendon 11, for example, various metals (iron or the like).
As shown in FIGS. 1 and 3 to 4, a viewing window 2 w is provided on the side surface of the anchor head support member 2. A cylindrical resin pipe 4 is inserted inward in the radial direction of the anchor head support member 2 having a cylindrical shape as a whole. The resin pipe 4 is made of a transparent resin (for example, acrylic resin).
As shown in FIG. 1, the vertical position of the viewing window 2 w is a position where the tendon 11 in the area immediately below the anchor head 7 can be seen, or a position where the most prone to deterioration and corrosion can be seen in the tendon 11. It is.
The position of the viewing window 2w in the circumferential direction is not particularly limited as long as it is a position where a field worker can visually recognize (view).

An anchor head 7 and a cap member 1 are attached above the anchor head support member 2. The cap member 1 is configured to cover the free end 11 e of the tendon 11.
In FIG. 1, the inside of the cap member 1 and the inside of the anchor head support member 2 are filled with, for example, grease as a corrosion inhibitor.
In FIG. 1, reference numeral 9a indicates a grease nipple, and reference numeral 9b indicates an air vent screw.

Details of the anchor head support member 2 are shown in FIG.
In FIG. 3, a flange portion 2 f is formed at the lower end portion of the cylindrical main body 2 a of the anchor head support member 2. The flange portion 2f is attached to the anchor plate 3 by fastening bolts BL.
A viewing window 2 w is formed on the side surface of the main body 2 a of the anchor head support member 2. A transparent resin pipe 4 is loosely fitted in the radially inner region of the main body 2a.
On the outer peripheral side of the upper end of the main body 2a of the anchor head support member 2, a male screw portion 2st is formed. The female screw portion 1st of the cap member 1 is screwed into the male screw portion 2st (see FIG. 1).

In FIG. 3, a step 2 k is formed on the inner peripheral side of the upper end of the main body 2 a of the anchor head support member 2. As shown in FIG. 1, the outer peripheral edge of the lower surface of the anchor head 7 is engaged with the step 2 k above the anchor head support member 2.
In FIG. 3, reference numeral 2 p indicates an insertion portion for inserting the water stop spacer 5.

The anchor head and the head rear structure described with reference to FIGS. 1 to 3 are tendons located in the radially inner space of the anchor head support member 2 and are most deteriorated and corroded. The tendon 11 in the region immediately below the easy anchor head 7 can be viewed (viewed) from the outside through the transparent resin pipe 4 and the viewing window 2w.
That is, the site worker visually observes (views) the visual window 2w to observe the tendon 11 in the region immediately below the anchor head 7 where deterioration or corrosion is most likely to proceed, and whether or not deterioration or corrosion has progressed. Can be determined.

Then, as a result of visual recognition (visual observation) from the visual window 2w, only the anchor head and the head rear structure, which are judged to be deteriorated or corroded, are disassembled to release the tendon tension, and the necessary parts Replacement and repair may be performed.
If it is determined that deterioration or corrosion has not progressed as a result of viewing (visually) from the viewing window 2w, it is necessary to release the tension of the tendon without disassembling the anchor head and head back structure. There is no.
In the first embodiment, the anchor head support member 2 receives the tension of the tendon 11 via the anchor head 7.

FIG. 4 shows an anchor head support member 2 according to a modification.
In the anchor head support member 2 shown in FIG. 3, a step 2 k provided on the inner periphery of the upper end is engaged with the anchor head 7. In other words, in the anchor head support member 2 shown in FIG. 3, only the step 2 k supports the tension acting on the tendon 11. However, since the area for supporting the tension of the tendon 11 is small in the step 2k, it is expected that the surface pressure or compressive stress acting on the step 2k will increase.
On the other hand, in the anchor head support member 2 shown in FIG. 4, a contact surface 2b extending radially inward from the stepped portion 2k is formed. The abutting surface 2 b also abuts on the anchor head 7 and supports the tension acting on the tendon 11.

In the modified example of FIG. 4, the contact surface 2b extending radially inward from the step 2k is formed so that the portion supporting the tension of the tendon 11 is expanded radially inward to achieve surface pressure or Compressive stress can be reduced.
Other configurations and operational effects in the modified example of FIG. 4 are the same as those described in FIGS.

Next, a second embodiment will be described with reference to FIG.
The second embodiment in FIG. 5 differs from the first embodiment in FIGS. 1 to 4 in the manner of attaching the anchor head support member and the cap member.
That is, in the first embodiment shown in FIGS. 1 to 4, the female screw portion 1 st at the lower end portion of the cap member 1 is screwed into the male screw portion 2 st formed on the outer periphery of the upper end portion of the anchor head support member 2. A head support member 2 and a cap member 1 are attached.

On the other hand, in FIG. 5, a flange 2Af is formed at the upper end of the anchor head support member 2A, and a flange 1Af is formed at the lower end of the cap member 1A. The flange 2Af and the flange 1Af are formed by bolts BL2. It is concluded.
In 2nd Embodiment of FIG. 5, the surface pressure in the coupling | bond part of 2 A of anchor head support members and the cap member 1A falls by bolting flange 2Af and flange 1Af. Further, the anchor head support member 2A and the cap member 1A are strongly coupled.
Other configurations and operational effects in the second embodiment of FIG. 5 are the same as those of the first embodiment of FIGS. Therefore, the configuration shown in FIGS. 4 and 4 can be applied to the second embodiment of FIG.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1, 1A ... Cap member 2, 2A ... Anchor head support member 2w ... Viewing window 3 ... Anchor plate 4 ... Resin pipe 5 ... Water stop spacer 7 ... Anchor Head 10 ... Frame 11 ... Tendon

Claims (2)

  A support plate that supports the tension acting on the tension support member, an anchor head support member mounted on the support plate, and an anchor head that adheres to the vicinity of the upper end of the tension support member. An anchor head and head back structure, wherein the anchor head is filled with an inhibitor and a viewing window is provided on the anchor head support member.   A tendon is inserted inside the anchor head support member, and a concave portion in which the anchor head can be installed is formed above the anchor head support member. A pipe made of a transparent material inserted into the anchor head support member is provided. The anchor head and head back structure according to claim 1.

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