JP3636632B2 - Anchor structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anchor hardware and an anchor structure for post-installation for reinforcing and expanding an existing concrete structure.
[0002]
[Prior art]
Post-installed anchors are drilled holes in the existing reinforced concrete frame with a drill, etc. to the depth required to anchor the anchor body, the anchor body is embedded in the anchor hole, and a reinforcing member such as steel is attached to the anchor body. The anchors are roughly classified into mechanical anchors (bottom expansion anchors) and adhesive anchors (resin anchors).
[0003]
Of these, in the case of adhesive anchors (resin anchors), the anchor length is required to be longer than that of metal anchors, and when a crack occurs in the anchoring portion due to repeated loads during an earthquake, the anchor body easily escapes from the anchor hole. In addition, when constructing the anchor body to extend downward at a vertically upper position, it is difficult to fix the reinforcing bar by preventing the resin from flowing out from the inside of the anchor hole, and high-quality construction is difficult. difficult.
[0004]
On the other hand, mechanical anchors usually have slits in the anchor body, etc., and are provided with an expanded portion that spreads like a skirt. After inserting the anchor body into an anchor hole drilled in a concrete structure, the expanded portion is expanded in the hole. It is established by this expansion force.
[0005]
In order to make the anchor fastening reliable with such a mechanical anchor, an anchor structure as shown in FIGS. 5 to 10 has also been proposed.
[0006]
First, as shown in FIG. 5, the anchor hole 2 having a specified depth is drilled in the existing concrete structure 1 with a drilling tool such as a pilot hole bit 8 in the same manner as in the ordinary drill hole construction. The chips are removed with a cleaner 3 as shown.
[0007]
Next, as shown in FIG. 7, the undercutter 9 is inserted into the anchor hole 2 to form an enlarged diameter portion (an enlarged bottom portion) 2 a in the vicinity of the hole bottom. The formation position of the enlarged diameter portion 2a corresponds to the position of the expansion member of the anchor, and is formed by cutting the hole wall.
[0008]
As an example, the undercutter 9 is provided with a pair of plate pieces 9b having an appropriate elasticity, which are formed to face each other by machining the main body 9a, at the lower part of the main body 9a, and a cutting edge 9c is provided at the lower end thereof. Is engaged with a guide groove provided on the overhanging rod 9e of the wedge center 9d so that the main body 9a can be extended outward by a downward movement so that the main body 9a is pushed into the anchor hole 2 while being rotated. In this case, the diameter of the hole wall is increased to a position where the cutting blade 9c moves on the overhanging rod 9e and protrudes outward from the overhanging rod 9e, thereby forming the expanded diameter portion (bottomed portion) 2a.
[0009]
As shown in FIG. 8, the chips are removed by the cleaner 3. An anchor is inserted into the anchor hole 2 formed in this way as shown in FIG. When the sleeve 7 is driven with the driving rod 10, the expansion member 6 is pressed downward, the plurality of expansion pieces 6a move onto the taper portion 4a of the Anzek bolt 4, and each expansion piece 6a expands along the taper portion 4a. Then, it is press-fitted into the enlarged diameter portion 2a, and the anchor is fixed in the anchor hole 2 by the expansion force of the expansion piece 6a.
[0010]
A screw portion 5 is formed at the upper end portion of the Anzek bolt 4 and, as shown in FIG. 10, the bolt hole of the mounting member 11 is inserted, and then the nut 13 is screwed in via the washer 12 to fasten the mounting member 11. .
[0011]
[Problems to be solved by the invention]
The mechanical anchor shown in FIGS. 5 to 10 mechanically connects a bolt to an undercut hole and reduces stress applied to the concrete. There is a problem with cracks in the concrete structure 1, and sufficient anchorage in the anchor holes cannot be expected.
[0012]
Further, the fixing location is limited by the relationship of the Anzek bolt 4, and as a result, the fixing length and the protruding length cannot be adjusted.
[0013]
The object of the present invention is to eliminate the inconveniences of the conventional example, can be reliably fixed with a shorter fixing length than the adhesive anchor, has high initial rigidity and adhesion performance, and has high reliability against cracks. Also, it is an object of the present invention to provide an anchor structure that can be freely set as a fixing length and a protruding length and is easy to use as an anchor hardware.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, firstly, the diameter of the hole wall is enlarged and cut into an anchor hole formed in an existing concrete structure to form an enlarged portion of the upper concavity. A screw rod as the main body, a tapered nut formed with a tapered portion on the upper portion that is screwed to the screw rod, and an expansion piece that is pushed and expanded by contacting the tapered portion of the nut are attached to the lower portion of the ring body. Insert an anchor hardware consisting of a skirt-shaped expanded metal fitting into the skirt, push the expanded metal fitting with a jig to expand the expanded piece, engage it with the expanded diameter portion of the hole wall, and The gist is that the filler is filled in the gap between the anchor hole and the anchor hole.
[0015]
Secondly, in the diameter-expanding metal fitting, the extended piece defined by the vertical cut from below is continuous to the ring body through the thin-walled hinge part, and thirdly, the thin-walled hinge part between the ring body and the extended piece. The gist of the present invention is to form a groove-shaped recess on the outer side of the screw, and fourthly, to fasten an attachment member such as a steel material to the screw rod.
[0016]
According to the first aspect of the present invention, the advantage of both the mechanical anchor and the resin anchor is utilized, and the screw rod as the anchor body is fixed in the anchor hole by the expansion force of the expansion piece. Further, the fixing can be made stronger with a filler such as resin and mortar, and high reliability against cracking can be obtained by filling the filler. Furthermore, the screw rod as the anchor body has high adhesion performance to the filler due to the presence of the screw groove.
[0017]
In addition, since it is fixed in the hole whose diameter has been expanded in advance, it does not give an initial stress to the existing concrete, and the initial rigidity against tension is high by filling with a filler such as resin or mortar.
[0018]
In addition to this, since the tapered nut is screwed to the screw rod, the position thereof can be freely changed, and as a result, the position where the expansion piece of the diameter expanding metal member is expanded can be freely changed with respect to the screw rod. Thereby, the fixing length and the protrusion length in the anchor hole of the screw rod can be freely set.
[0019]
According to the second aspect of the present invention, in addition to the above-described function, the diameter-expanding metal fitting is integrated with the ring body and the extension piece via the thin hinge portion, and is not divided into two parts. The piece can be smoothly expanded with a small force due to the presence of the thin hinge portion.
[0020]
According to the third aspect of the present invention, the groove-shaped recess formed on the outer side of the thin hinge portion between the ring body and the expansion piece secures a clearance for bending the expansion piece, and has a relatively large angle. Bending is possible.
[0021]
According to the fourth aspect of the present invention, an attachment member such as a steel material is fastened to the screw rod, which is optimal for attaching an iron plate, a bracket, an iron pillar, or the like to the existing concrete.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 2 are partially cutaway front views showing an anchor hardware used in the anchor structure of the present invention, and a screw rod 14 as an anchor body is used.
[0023]
In the figure, reference numeral 15 denotes a nut that is screwed onto the threaded rod 14, and the lower part is a hexagonal nut, but a tapered nut having a conical taper part 15a with a constriction at the upper part formed in the upper part.
[0024]
Reference numeral 16 denotes a diameter-enlarging metal fitting, which includes a ring body 19 and an expansion piece 17 formed in a skirt shape below the ring body 19 and has six expansion pieces that are partitioned by a longitudinal cut from below. 17 are continuous with the ring body 19 via the thin-walled hinge portions 18.
[0025]
The extension piece 17 is a thick piece about three times thicker than the ring body 19 (about 2 mm), and the thin hinge portion 18 is less than half the thickness of the ring body 19. In this way, the groove-shaped recess 20 is formed between the ring body 19 and the extension piece 17 on the outer side of the thin hinge portion 18.
[0026]
A lock nut 21 is screwed onto the end of the screw rod 14, a tapered nut 15 is screwed thereon, and the diameter-expanded metal fitting 16 is positioned so that the screw rod 14 penetrates the ring body 19 thereon. The positions of the locking nut 21 and the tapered nut 15 can be freely set with respect to the screw rod 14 by adjusting the screw.
[0027]
Further, as another embodiment, the retaining nut 21 may be omitted, and a hexagonal nut may be provided at the lower portion of the tapered nut 15 correspondingly.
[0028]
Next, the anchor structure of the present invention using the anchor metal as described above will be described. As in the conventional example, first, the anchor hole 2 having a specified depth is drilled in the existing concrete structure 1 with a drilling tool such as a pilot hole bit 8 as shown in FIG. Then, the internal chips are removed by the cleaner 3 as shown in FIG.
[0029]
Next, the undercutter 9 is inserted into the anchor hole 2 as shown in FIG. As shown in FIG. 8, the chips are removed by the cleaner 3.
[0030]
The undercutter 9 is as described in the above-mentioned conventional example, and a pair of plate pieces 9b having appropriate elasticity, which are formed to face each other by cutting the main body 9a, are provided at the lower part of the main body 9a, and a cutting blade is provided at the lower end thereof. 9c is provided, and this cutting edge 9c is engaged with a guide groove provided on the overhanging rod 9e of the wedge center 9d so that it can be extended outward of the main body 9a by downward movement.
[0031]
As shown in FIG. 2, a screw rod 14 screwed with a locking nut 21 and a tapered nut 15 is inserted into the anchor hole 2 formed in this way, and the diameter-expanding metal fitting 16 is dropped onto the tapered nut 15. If the diameter-expanding metal fitting 16 is driven by a driving rod as a jig directly or via the sleeve 7 so as to fit on the tapered nut 15, the diameter-expanding metal fitting 16 is pressed downward as shown in FIG. The expanded piece 17 moves onto the tapered portion 15a of the tapered nut 15, the expanded pieces 17 expand along the tapered portion 15a, and are press-fitted into the expanded diameter portion 2a. The screw rod 14 is fixed in the anchor hole 2 by the expansion force of the expansion piece 17.
[0032]
By dropping the diameter expansion fitting 16, the thin hinge 18 is bent without difficulty because the expansion piece 17 is pushed up while being joined to the taper portion 15 a of the tapered nut 15, and the groove-like recess 20 is bent of the expansion piece 17. Therefore, a relatively large angle can be bent.
[0033]
Thereafter, a filler 22 such as resin or mortar is injected into the gap (including the enlarged diameter portion 2 a) between the screw rod 14 and the existing concrete structure 1, thereby fixing the screw rod 14 to the anchor hole 2. Therefore, even if a certain amount of cracking occurs in the fixing portion due to seismic force or other causes, the pull-out resistance of the screw rod 14 increases due to the concrete bearing resistance of the enlarged diameter portion 2a. The filler 22 also prevents corrosion of the screw rod 14.
[0034]
A washer 12 and a nut 13 are fitted to the screw rod 14, and an attachment member 23 such as a steel material is fastened. The attachment member 23 can be a variety of objects such as an iron plate that covers the surface of the existing concrete structure 1, a reinforcing steel frame, a bracket, a base plate of an iron pillar, and the like.
[0035]
【The invention's effect】
As described above, the anchor structure of the present invention can be reliably fixed with a shorter fixing length than the adhesive anchor, has high initial rigidity and adhesion performance, and has high reliability against cracks. The fixing length and protrusion length can be set freely, making it easy to use as an anchor hardware.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view of an anchor structure according to an embodiment of the present invention after an anchor hardware is installed.
FIG. 2 is a partially cutaway front view showing an embodiment of the anchor structure of the present invention in the middle of anchor metal installation.
FIG. 3 is a partially cutaway front view of an anchor hardware used in the anchor structure of the present invention before expansion.
FIG. 4 is a partially cutaway front view of an anchor hardware used in the anchor structure of the present invention after expansion.
FIG. 5 is a longitudinal sectional front view showing a first construction process of a conventional example.
FIG. 6 is a longitudinal front view showing a second construction process of a conventional example.
FIG. 7 is a longitudinal sectional front view showing a third construction process of a conventional example.
FIG. 8 is a longitudinal sectional front view showing a fourth construction process of a conventional example.
FIG. 9 is a longitudinal sectional front view showing a fifth construction step of a conventional example.
FIG. 10 is a longitudinal sectional front view showing a sixth construction process of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Concrete structure 2 ... Anchor hole 2a, 2b ... Diameter expansion part 3 ... Cleaner 4 ... Anzek bolt 4a ... Taper part 5 ... Screw part 6 ... Expansion member 6a ... Expansion piece 7 ... Sleeve 8 ... Bit for pilot hole 9 ... Under cutter 9a ... Main body 9b ... Plate piece 9c ... Cutting blade 9d ... Wedge center 9e ... Overhang rod 10 ... Pieting rod
11 ... Mounting member 12 ... Washer
13 ... Nut 14 ... Threaded rod
14a ... Screw 15 ... Nut
15a ... Taper part 16 ... Diameter expansion fitting
17 ... Expansion piece 18 ... Thin hinge part
19 ... Ring body 20 ... Groove-shaped recess
21 ... Stop nut 22 ... Filler
23… Mounting member

Claims (4)

The hole wall is enlarged and cut into the anchor hole formed in the existing concrete structure to form the enlarged portion of the upper constriction, and the screw rod as the anchor body and the screw rod are screwed into the anchor hole. An anchor hardware consisting of a tapered nut with an upper tapered portion at the top and an expanded fitting formed in a skirt shape at the bottom of the ring body with an expansion piece that is pushed and expanded in contact with the tapered portion of the nut. The expansion piece is expanded by pushing the expansion metal fitting with a jig, and this is engaged with the expanded diameter portion of the hole wall, and further, a filler is filled in the gap between the screw rod and the anchor hole. An anchor structure characterized by that. 2. The anchor structure according to claim 1, wherein the expansion fitting is divided into a ring body through a thin hinge portion. The expansion piece is partitioned by a longitudinal cut from below. The anchor structure according to claim 2, wherein a groove-like recess is formed outside the thin hinge portion between the ring body and the extension piece. The anchor structure according to any one of claims 1 to 3, wherein an attachment member such as a steel material is fastened to the screw rod.

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