Anchor bolt construction method

Abstract

To provide an anchor bolt construction method for constructing an anchor bolt in an existing concrete skeleton easily with high quality.SOLUTION: An anchor bolt construction method is provided with: a boring step of boring a through hole in an existing concrete skeleton; a shield step of shielding a hole at a tip side of the through hole with a lid member 4; an injection step of injecting filler from a hole at a base end side of the through hole; and an insertion step of inserting the anchor bolt from the hole of the base end side of the through hole. In the lid member 4, an insertion hole 41 into which the anchor bolt is penetrable is formed and a sheet member 5 shielding the insertion hole is installed in a surface at a side of the existing concrete skeleton, wherein in the insertion step, the sheet member 5 is broken through with a tip of the anchor bolt to insert the tip of the anchor bolt into the through hole 41.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for installing an anchor bolt. [Background technology]

[0002] As a method for reinforcing an existing concrete structure, there is a case where reinforcing members (bridge fall prevention materials, steel plates, additional concrete, etc.) are added to the surface of the existing concrete skeleton. As a method for fixing such reinforcing members, there is a case where anchor bolts are fixed to the existing concrete skeleton by post-construction, and the reinforcing members are fixed to these anchor bolts. For example, Patent Document 1 discloses a reinforcement structure in which a reinforcing plate is fixed to the end of a bolt member (anchor bolt) that penetrates an existing concrete skeleton. The bolt member of the reinforcement structure in Patent Document 1 is inserted into an anchor hole formed in the existing concrete skeleton by post-construction, with both ends protruding from the side surface of the existing concrete skeleton and fixed by a filler material filled in the anchor hole. The general procedure for installing an anchor bolt is to insert the anchor bolt into an anchor hole formed in the existing concrete structure, install an injection pipe for injecting filler while covering the opening of the bolt hole, and fill the anchor hole with filler from the injection pipe while removing the air from the anchor hole (see, for example, Patent Document 2). The conventional anchor bolt installation method requires the laborious task of laying the injection pipe. In addition, the injection pipe is cut after the filler hardens, but it is necessary to process it smoothly so that it does not protrude from the surface of the existing concrete structure. In addition, since the filler is filled into the small gap between the anchor hole and the anchor bolt, it is necessary to use a low-viscosity material such as cement milk as the filler. However, low-viscosity filler does not easily adhere to the upper part of the anchor hole, so air pockets (unfilled areas) are likely to form in the upper part of the anchor hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-092005 A [Patent Document 2] JP 2000-248750 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to propose an anchor bolt installation method that enables easy and high-quality installation of anchor bolts into an existing concrete structure. [Means for solving the problem]

[0005] The anchor bolt installation method of the present invention for solving the above problems includes a drilling step of forming a through hole in an existing concrete structure, a shielding step of shielding the tip end side opening of the through hole with a cover material, an injection step of injecting a filler material from the base end side opening of the through hole, and an insertion step of inserting an anchor bolt from the base end side opening of the through hole. The cover material has an insertion hole through which the anchor bolt can be inserted, and a sheet material that shields the insertion hole is installed on the surface of the existing concrete structure side. Then, in the insertion step, the tip of the anchor bolt is inserted into the insertion hole while breaking through the sheet material with the tip of the anchor bolt.

[0006] This anchor bolt construction method is excellent in workability because it does not require work such as smoothing the surface of the existing concrete structure after construction. In addition, since the filler is injected into the through hole before the anchor bolt is inserted, a highly viscous material can be used as the filler. If a highly viscous filler is used, unfilled areas (air pockets) are unlikely to form in the upper part of the through hole, allowing for high-quality construction. When the anchor bolt is inserted into the insertion hole of the lid material, the anchor bolt breaks through the sheet material, so the filler is unlikely to leak out from the tip side of the through hole.

[0007] If the sheet material is a cloth tape, the fibers of the sheet material become entangled with the anchor bolt when the anchor bolt is inserted into the insertion hole of the lid material, thereby further suppressing leakage of the filler material. Furthermore, if the anchor bolt is inserted with its tip covered with a protective material, it is possible to prevent the filler material from adhering to the threaded portion even if the tip of the anchor bolt is threaded. Furthermore, it is preferable that the method further comprises a refilling step of refilling a filler material from the base end side hole opening after the inserting step. Effect of the Invention

[0008] According to the anchor bolt installation method of the present invention, it is possible to install an anchor bolt in an existing concrete structure easily and with high quality. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a cross-sectional view showing an installation state of an anchor bolt according to an embodiment of the present invention. [Diagram 2] 4 is a flowchart showing the steps of an anchor bolt installation method. [Diagram 3] 1A and 1B are cross-sectional views showing steps of an anchor bolt installation method, in which (a) is a hole drilling step and (b) is a shielding step. [Figure 4] FIG. [Diagram 5] 1A and 1B are cross-sectional views showing steps of an anchor bolt installation method, in which (a) is an injection step and (b) is an insertion step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following describes an anchor bolt installation method for installing anchor bolts in an existing concrete structure. An anchor bolt 1 is shown in Fig. 1. As shown in Fig. 1, the anchor bolt 1 is installed in a state in which it penetrates a through hole 21 formed in an existing concrete skeleton 2 so that both ends protrude from the side surfaces of the existing concrete skeleton 2. A filler material 3 is filled in the gap between the anchor bolt 1 and the through hole 21. Both ends of the anchor bolt 1 of this embodiment are threaded to form male threads 11, 11.

[0011] The steps of the anchor bolt installation method are shown in Figure 2. As shown in Figure 2, the method includes a hole drilling step S1, a shielding step S2, an injection step S3, an insertion step S4, and a replenishing step S5. Fig. 3(a) shows the hole drilling step S1. As shown in Fig. 3(a), in the hole drilling step S1, a through hole 21 is formed in an existing concrete skeleton 2. The through hole 21 has an inner diameter larger than the outer diameter of the anchor bolt 1. The through hole 21 is formed horizontally by core boring. After drilling, the inside of the through hole 21 is cleaned, and cutting chips and the like are removed from inside the through hole 21.

[0012] FIG. 3(b) shows the shielding step S2. As shown in FIG. 3(b), in the shielding step S2, the tip side opening of the through hole 21 is shielded by the lid material 4. FIG. 4 shows the lid material 4. As shown in FIG. 4, the lid material 4 is made of a plate material in which an insertion hole 41 through which the anchor bolt 1 can be inserted is formed. In this embodiment, the lid material 4 is made of a wooden plate material such as a so-called plywood. The lid material 4 has a width and height (e.g., 100 mm×100 mm) that are sufficiently large compared to the diameter of the through hole 21. The insertion hole 41 has an inner diameter (e.g., bolt diameter+2 mm) that is smaller than the diameter of the through hole 21 and is equal to or larger than the outer diameter of the anchor bolt 1. A sheet material 5 that shields the insertion hole 41 is installed (attached) on the surface of the lid material 4 facing the existing concrete skeleton 2. The sheet material 5 is, for example, a cloth tape, and has an adhesive layer on one side. In this embodiment, the lid material 4 is fixed to the existing concrete skeleton 2 by concrete screws 6. The concrete screws 6 are attached to the lid material 4 diagonally, and penetrate the corners of the lid material 4.

[0013] Fig. 5(a) shows the injection step S3. As shown in Fig. 5(a), in the injection step S3, the filler 3 is injected from the base end side hole opening of the through hole 21. The filler 3 is made of an inorganic material (e.g., non-shrink mortar). In this embodiment, the filler 3 is injected from the tip side (the lid material 4 side) of the through hole 21 using a hand gun (not shown). The amount of the filler 3 injected in the injection step S3 is equal to or more than the amount obtained by subtracting the volume of the length of the through hole 21 of the anchor bolt 1 from the internal volume of the through hole 21.

[0014] The insertion step S4 is shown in Fig. 5(b). As shown in Fig. 5(b), in the insertion step S4, the anchor bolt 1 is inserted from the base end side hole opening of the through hole 21. In the insertion step S4, the tip of the anchor bolt 1 is inserted into the insertion hole 41 while breaking through the sheet material 5 with the tip of the anchor bolt 1. At this time, the tip of the anchor bolt 1 (around the male thread 11) is covered with a protective material 7. For example, a polyethylene tape may be used as the protective material 7.

[0015] In the refilling step S5, filler 3 is refilled from the base end side hole opening of through hole 21. In the refilling step S5, the amount of filler 3 that leaked out from the base end side hole opening when anchor bolt 1 was inserted is refilled. The base end side hole opening is finished to be flat using a spatula or the like. The refilled filler 3 may be newly refilled, or the filler that leaked out from the base end side hole opening may be used. After the filling material 3 has been cured, the lid material 4 and the protective material 7 are removed.

[0016] As described above, according to the anchor bolt construction method of the present embodiment, there is no need for the time and effort of installing an injection pipe, and there is also no need for work such as grinding to smooth the surface of the existing concrete body 2 after construction, resulting in excellent workability. In addition, since the filler 3 is injected into the through hole 21 before the anchor bolt 1 is inserted, a highly viscous material can be used for the filler 3. Therefore, unfilled areas (air pockets) are unlikely to form in the upper part of the through hole 21, allowing for high-quality construction. When the anchor bolt 1 is inserted into the insertion hole 41 of the lid material 4, the anchor bolt 1 breaks through the sheet material 5 made of cloth tape, and the sheet material 5 becomes entangled with the anchor bolt 1, blocking the gap between the insertion hole 41 of the lid material 4 and the anchor bolt 1, so that the filler material 3 is less likely to leak out from the tip side of the through hole 21. In addition, since the anchor bolt 1 is inserted into the through hole 21 with the tip portion of the anchor bolt 1 covered with the protective material 7, it is possible to prevent the filler material 3 in the through hole 21 from adhering to the male thread 11 at the tip of the anchor bolt 1.

[0017] Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention. The replenishing step S5 may be performed as necessary, and may be omitted if the gap between the through hole 21 and the anchor bolt 1 is filled with the filler material 3 when the insertion step S4 is completed. The protective material 7 may be installed as necessary, and may be omitted, for example, when the anchor bolt 1 is a steel bar or reinforcing bar. The material constituting the sheet material 5 is not limited to cloth tape, and may be, for example, polyethylene tape or paper tape, as long as it is a material that can prevent leakage of the filler 3 and can be broken through by the anchor bolt 1. Also, it may be a vinyl sheet or paper without an adhesive layer. The method of injecting the filler 3 into the through hole 21 in the injection step is not limited to the method using a hand gun, and may be, for example, a method using an injection tube. When using an injection tube, the injection of the filler 3 may be started with the tip of the injection tube positioned near the lid member 4, and the injection tube may be gradually withdrawn while injecting the filler. Alternatively, a container (capsule, bag, etc.) filled with the filler 3 may be inserted into the through hole 21, and when the anchor bolt 1 is inserted into the through hole 21 in the insertion step, the anchor bolt 1 may break through the container, thereby filling the through hole 21 with the filler 3. [Explanation of symbols]

[0018] 1 Anchor bolt 11 Male thread 2 Existing concrete structure 21 Through hole 3 Filling material 4 Lid material 41 Insertion hole 5 Sheet material 6 Concrete screws 7 Protective materials S1 Hole drilling process S2 shielding process S3 injection process S4 Insertion process S5 Replenishment process

Claims

1. A drilling process for forming a through hole in the existing concrete structure; a covering step of covering a tip side opening of the through hole with a cover material; an injection step of injecting a filler material from a base end side opening of the through hole; and an inserting step of inserting an anchor bolt from a base end side hole opening of the through hole, The cover material has an insertion hole through which the anchor bolt can be inserted, and a sheet material for covering the insertion hole is installed on a surface of the existing concrete structure side, The method for installing an anchor bolt, wherein in the inserting step, the tip of the anchor bolt is inserted into the insertion hole while breaking through the sheet material with the tip of the anchor bolt.

2. 2. The anchor bolt installation method according to claim 1, wherein the sheet material is a cloth tape.

3. 2. The anchor bolt installation method according to claim 1, wherein in the inserting step, the anchor bolt is inserted in a state in which a tip portion of the anchor bolt is covered with a protective material.

4. 2. The anchor bolt installation method according to claim 1, further comprising a refilling step of refilling a filler material from the base end side hole opening after the inserting step.

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