JP7362210B2 - Construction method of concrete anchors - Google Patents

Description

The present invention relates to a method for constructing a concrete anchor by removing an existing anchor installed in a concrete frame and replacing it with a new anchor.

When anchors are installed on a concrete frame and an attachment is attached, it is possible to remove the anchor that is no longer needed due to rust, etc. or that is not compatible with the new attachment and replace it with another new anchor. be. For example, we have patented a main body driving type anchor consisting of a main body with a female thread formed on the inner periphery into which a mounting bolt is screwed, an expanding piece formed on the tip side, and a cone that is press-fitted into the main body when the main body is driven. Anchor removal tools such as those described in Documents 1 and 2 are used to pull out and remove the anchor from the concrete structure, and in place of the removed existing anchor, another new anchor is cast into the concrete structure.

At this time, as shown in FIG. 10, the existing hole 301 left in the concrete frame 300 by placing the existing anchor is backfilled with mortar 302, and a new hole is drilled at another location nearby. A new hole 303 is formed by doing this, and another new anchor is driven into the new hole 303 at a different location. In FIG. 10, S10 is a supposed failure surface of the concrete frame 300, and R10 is a stress-loaded area where tensile stress is continuously applied by an existing anchor.

Note that Patent Document 3 discloses a partially enlarged diameter portion cutting tool that forms a partially enlarged diameter portion in the middle of a hole formed in a concrete frame in the longitudinal direction.

JP2015-71216A Japanese Patent Application Publication No. 2005-66725 Japanese Patent Application Publication No. 2012-71505

By the way, as mentioned above, in the construction method in which the existing hole 301 left after driving the existing anchor is filled with mortar 302 and then a new hole 303 is formed at another location, the mortar for backfilling the existing hole 301 is Injection work requires labor and construction efficiency is poor. Furthermore, since a new hole 303 for driving a new anchor is drilled near the backfilled existing hole 301, the concrete frame 300 becomes full of holes, which places a large load on the concrete frame and reduces its strength and durability. There are concerns about a decline in sexuality.

The present invention is proposed in view of the above-mentioned problems, and is not only highly efficient in construction, but also capable of minimizing the load applied to the concrete frame and reliably maintaining the strength and durability required for the concrete frame. The purpose is to provide a construction method for concrete anchors.

The concrete anchor construction method of the present invention includes the first step of extracting the existing original anchor from the existing hole in the concrete structure, and drilling a new hole concentrically with the existing hole with a diameter larger than the existing hole. The present invention is characterized by comprising a second step of drilling a hole, and a third step of driving a new updated anchor into the new hole.
According to this, mortar injection work for backfilling the existing hole becomes unnecessary, and the construction efficiency of the concrete anchor can be improved. Additionally, since there is no need to create new holes in new locations in the concrete structure that are different from existing holes, the load on the concrete structure can be kept to a minimum and the strength and durability required for the concrete structure can be ensured. can be maintained. In addition, by driving the updated anchor into a newly drilled hole with a larger diameter than the existing hole, the area of healthy concrete outside the stressed area where the original anchor applied tensile stress can be used to update the area. Anchors can be made to work reliably. In addition, by forming a new hole concentrically with the existing hole and with a diameter larger than the existing hole, the existing hole can be used as a guide hole to form a straight and concentric new hole. , Also from this point of view, the construction efficiency of concrete anchors is excellent.

The concrete anchor construction method of the present invention is characterized in that, in the second step, the new hole is drilled to a depth that is deeper than the existing hole.
According to this, by driving a renewed anchor into a newly drilled hole that is deeper than the existing hole, a healthy concrete area outside the stressed area where the original anchor applied tensile stress can be used. can be used more extensively to ensure that update anchors work more reliably.

The method for constructing a concrete anchor of the present invention includes a first step of extracting an existing original anchor from an existing hole in a concrete frame, and drilling a new hole concentrically with the existing hole to a depth deeper than the existing hole. The present invention is characterized by comprising a second step of drilling a hole, and a third step of driving a new updated anchor into the newly created hole.
According to this, mortar injection work for backfilling the existing hole becomes unnecessary, and the construction efficiency of the concrete anchor can be improved. Additionally, since there is no need to create new holes in new locations in the concrete structure that are different from existing holes, the load on the concrete structure can be kept to a minimum and the strength and durability required for the concrete structure can be ensured. can be maintained. In addition, by driving the updated anchor into a newly drilled hole that is deeper than the existing hole, it is possible to utilize the healthy concrete area outside the stressed area where the original anchor applied tensile stress. You can ensure that update anchors are effective.

The construction method of the concrete anchor of the present invention is such that the original anchor has a main body formed with a female thread on the inner periphery into which a mounting bolt is screwed and an expansion piece formed on the distal end side, and a main body formed from the distal end side to the main body side. The anchor is a main body driving type anchor consisting of a cone that is press-fitted and expands the expansion piece, and the renewal anchor is provided with a tapered portion that gradually increases in diameter toward the tip on the distal end side of the base, and It is a sleeve-driving type anchor consisting of an inner member with a female thread formed on the inner periphery of which the mounting bolt is screwed, and a sleeve provided with an expansion piece on the distal end side that expands when the tapered part is press-fitted. It is characterized by
According to this, the main body driving type anchor can be easily extracted and removed using, for example, an existing anchor extraction tool. In addition, the sleeve-driving type anchor, which is considered to be a renewal anchor, has a mounting bolt screwed into the female thread of the inner member, and when a load is applied to the mounting bolt, the tapered part is pulled in by the expansion piece, creating an expansion force and fixing the anchor. By increasing the force, the fixing power and supporting power of the updated anchor can be further increased.

The method for constructing a concrete anchor according to the present invention includes a first step of extracting an existing original anchor from an existing hole in a concrete structure, and forming a partially enlarged diameter portion concentrically with the existing hole in a part of the hole in the depth direction. and a third step of driving a new renewal anchor into the newly created hole by inserting the expanded expansion piece into the partially enlarged diameter portion. do.
According to this, mortar injection work for backfilling the existing hole becomes unnecessary, and the construction efficiency of the concrete anchor can be improved. Additionally, since there is no need to create new holes in new locations in the concrete structure that are different from existing holes, the load on the concrete structure can be kept to a minimum and the strength and durability required for the concrete structure can be ensured. can be maintained. In addition, by driving the updated anchor into a new hole that is concentric with the existing hole and has a partially enlarged diameter section in the hole depth direction, it is possible to remove the stress-loaded area where the original anchor applied tensile stress. Areas of sound concrete on the outside can be used to ensure that the renewal anchors are effective.

In the concrete anchor construction method of the present invention, in the second step, the new hole is drilled with a diameter larger than that of the existing hole, or the new hole is drilled with a depth deeper than the existing hole. The method is characterized in that a new hole is drilled, or the new hole is drilled with a diameter larger than that of the existing hole and a drilling depth that is deeper than the existing hole.
According to this, a new hole with a larger diameter than the existing hole, a new hole with a deeper drilling depth than the existing hole, or a hole with a larger diameter than the existing hole and a deeper hole than the existing hole. By driving the replacement anchor into a newly drilled hole with a deep drilling depth, the replacement anchor can be installed using a wider area of sound concrete outside the stressed area where the original anchor applied tensile stress. can be more reliably effective.

The method for constructing a concrete anchor according to the present invention is such that the original anchor has a main body formed with a female thread on the inner periphery into which a mounting bolt is screwed and an extension piece formed on the tip side, and a main body side by driving the main body. This is a main body driving type anchor consisting of a cone press-fitted into the main body, and the renewal anchor is provided with a tapered part on the distal end side of the base that gradually increases in diameter toward the distal end, and a male threaded part on the rear end side of the base. The anchor is characterized by being an expansion-bottom anchor comprising a shaft body provided with a base cylinder, and an outer member provided with an expansion piece that expands by press-fitting the tapered part through a thin wall part on the distal end side of the base cylinder. .
According to this, the main body driving type anchor can be easily extracted and removed using, for example, an existing anchor extraction tool. In addition, the expanded bottom type anchor, which is considered as an updated anchor, opens an expanded piece at the partially expanded diameter part in a newly installed hole that has a partially expanded diameter part, and when a force in the pulling direction is applied to the shaft body, the expanded piece extends outward from the opened expanded piece. Since the force acts in the direction of pushing the concrete towards the concrete, it develops a very large anchoring force and can further increase the anchoring force and supporting force of the renewed anchor.

According to the concrete anchor construction method of the present invention, construction can be performed with excellent construction efficiency, and the load on the concrete framework can be minimized, ensuring the strength and durability required for the concrete framework. can be maintained.

(a) is an exploded front view of the original anchor that is replaced by the concrete anchor construction method of the embodiment according to the present invention, (b) is a right side view of the same original anchor, and (c) is an exploded front view of the original anchor that is replaced by the concrete anchor construction method according to the embodiment of the present invention. A vertical cross-sectional view, (d) is a cross-sectional explanatory view of a state in which the same anchor is cast into a concrete frame and an attachment is attached. (a) is an exploded front view of a renewed anchor replaced by the concrete anchor construction method of the first embodiment of the present invention, (b) is a longitudinal cross-sectional view of the sleeve and inner member of the renewed anchor, and (c) is the same renewed anchor. An explanatory cross-sectional view showing a state in which an anchor is cast into a concrete frame and an attachment is attached. (a) to (f) are explanatory diagrams illustrating the construction procedure of the concrete anchor construction method of the first embodiment. FIG. 3 is an explanatory diagram illustrating a stress-loaded area on a concrete frame by the original anchor replaced in the concrete anchor construction method of the embodiment. FIG. 2 is an explanatory diagram illustrating the installation state of an updated anchor to be replaced by the concrete anchor construction method of the first embodiment. 2 is a graph showing the results of a pull-out loading test of an updated anchor replaced by the concrete anchor construction method of the first embodiment and an original anchor replaced with the updated anchor. (a) is a front view of the updated anchor replaced by the anchor construction method of the second embodiment of the present invention, (b) is an AA end view of the same figure (a), and (c) is a longitudinal cross-section of the updated anchor. (d) is a front view of the shaft of the updated anchor, (e) is a cross-sectional explanatory diagram of the updated anchor placed in the concrete frame, and (f) is the updated anchor placed in the concrete frame. FIG. (a) to (f) are explanatory diagrams illustrating the construction procedure of the concrete anchor construction method of the second embodiment. FIG. 7 is an explanatory diagram illustrating the installation state of an updated anchor to be replaced by the concrete anchor construction method of the second embodiment. Explanatory diagram illustrating replacement of anchors in a conventional concrete frame.

[Construction method of concrete anchor of the first embodiment]
The method for constructing a concrete anchor according to the first embodiment of the present invention is to remove the existing original anchor 50 shown in FIG. This is a construction method in which a new updated anchor 10 shown in FIG. 2 is driven into the newly installed hole 102.

The original anchor 50 in FIG. 1 is a main body driving type anchor, and has a substantially cylindrical main body 51 and a cone 52 inserted into the distal end side of the main body 51. A female thread 511 is formed on the inner periphery of the rear portion of the main body 51, and a mounting bolt 53, which is a fully threaded bolt in the illustrated example, can be screwed into the female thread 511. A slit 512 is formed in the front portion of the main body 51 and extends in the axial direction by cutting from the tip thereof, and a plurality of slits 512 are provided at predetermined intervals in the circumferential direction. The portion between the slits 512 in the circumferential direction of the main body 51 is an expanding piece 513, and a plurality of expanding pieces 513 are provided on the distal end side of the main body 51 in a line in the circumferential direction. On the outer surface of the expansion piece 513, unevenness 514 is formed to increase the fixing force by frictional resistance.

The cone 52 has a substantially cylindrical and short base 521 and a tapered portion 522 that is provided on the distal end side of the base 521 and gradually increases in diameter toward the distal end. The outer diameter of the base portion 521 is approximately the same diameter as the inner diameter of the expansion piece 513 of the main body 51 in the non-expanded state, or is slightly smaller. A base 521 is fitted into the tip of the base 51 .

The original anchor 50 is cast into the existing hole 101 of the concrete frame 100 with the cone 52 disposed on the tip side, as shown in FIG. 1(d). In the original anchor 50 of the main body driving type anchor, the cone 52 is relatively press-fitted to the main body 51 side, in other words, the expansion piece 513 side by driving the main body 51 to the back side of the hole, and the cone 52 is The expansion piece 513 expanded by press-fitting is fixed so as to bite into the peripheral wall of the existing hole 101. Then, the mounting bolt 53 is screwed into the female thread 511 of the main body 51 that has been driven. An attachment 151 is inserted onto the screwed attachment bolt 53, a washer 161 is inserted onto the attachment bolt 53 from the outside of the attachment 151, a nut 162 is screwed, and the attachment 151 is attached to the concrete frame 100. .

The updated anchor 10 in FIG. 2 is a sleeve-driving type anchor to which a mounting bolt with the same thread diameter as the original anchor 50 is attached, and includes a substantially cylindrical sleeve 11 and an inner insert inserted into the distal end side of the sleeve 11. It has a member 12. A slit 111 is formed in the front part of the sleeve 11 and extends in the axial direction by being cut from the tip, and a plurality of slits 111 are provided at predetermined intervals in the circumferential direction. The portion between the slits 111 in the circumferential direction of the sleeve 11 is an expansion piece 112, and a plurality of expansion pieces 112 are provided on the distal end side of the sleeve 11 in a line in the circumferential direction. On the outer surface of the expansion piece 112, unevenness 113 is formed to increase the fixing force by frictional resistance.

The inner member 12 has a substantially cylindrical base portion 121 constituting a rear portion, and a tapered portion 122 formed on the distal end side of the base portion 121 so as to gradually increase in diameter toward the distal end. The outer diameter of the base 121 is approximately the same as or slightly smaller than the inner diameter of the expansion piece 112 of the sleeve 11 in the non-expanded state. The base portion 121 is fitted over a portion of the rear portion 114 from the piece 112, and the tapered portion 122 is disposed so as to project entirely toward the distal end side of the sleeve 11. A female thread 123 is formed on the inner periphery of the base 121 of the inner member 12, and the mounting bolt 13, which is a fully threaded bolt in the illustrated example, can be screwed into the female thread 123.

As shown in FIG. 2(c), the updated anchor 10 is cast into a new hole 102 of the concrete frame 100 with the inner member 12 disposed on the tip side. In the renewed anchor 10 of the sleeve-driving type anchor that has been driven, the tapered part 122 of the inner member 12 is relatively press-fitted to the sleeve 11 side, in other words, to the expansion piece 112 side by driving the sleeve 11 to the deep side of the hole. The expansion piece 112 expanded by press-fitting the tapered portion 122 is fixed so as to bite into the peripheral wall of the newly formed hole 102. Then, the mounting bolt 13 is screwed into the internal thread 123 of the inner member 12 that has been driven. An attachment 152 is inserted onto the screwed attachment bolt 13, a washer 163 is inserted onto the attachment bolt 13 from the outside of the attachment 152, a nut 164 is screwed, and the attachment 152 is attached to the concrete frame 100. .

When replacing the existing original anchor 50 with the updated anchor 10 in the concrete anchor construction method of the first embodiment, for example, the original anchor 50 is driven into the existing hole 101 of the concrete frame 100, and the attachment 151 is attached. In this state, the nut 162 and washer 161 are removed from the mounting bolt 53, the attachment 151 is removed from the mounting bolt 53, and the mounting bolt 53 screwed into the main body 51 of the original anchor 50 is removed from the main body 51. Then, by extracting the main body 51 and the cone 52 from the existing hole 101 using an existing anchor extraction tool such as those disclosed in Patent Documents 1 and 2, the existing original anchor 50 is extracted and removed from the existing hole 101 (FIG. 3 (see (a), (b)). In FIG. 3(b), D1 is the diameter of the existing hole 101, L1 is the depth of the existing hole 101, and the depth L1 of the existing hole 101 is the depth of the outer diameter portion of the existing hole 101.

Thereafter, as shown in FIGS. 3(c) and 3(d), a hole is drilled concentrically with the existing hole 101 using a drill 171, and the hole is larger in diameter than the existing hole 101 and deeper than the existing hole 101. A new hole 102 concentric with the existing hole 101 is drilled in the concrete frame 100 at the drilling depth. In FIG. 3(d), D2 is the diameter of the newly installed hole 102, and has a relationship of diameter D2 of the newly installed hole 102>diameter D1 of the existing hole 101. In addition, in FIG. 3(d), L2 is the depth of the new hole 102, and the depth L2 of the new hole 102 is the depth of the outer diameter part of the new hole 102, and the depth of the new hole 102 is the depth of the new hole 102. The relationship is L2>depth L1 of the existing hole 101.

Next, the sleeve 11 and inner member 12 of the new updated anchor 10, which is a sleeve-driving type anchor, are inserted into the new hole 102 with the inner member 12 disposed on the distal end side. Then, the sleeve 11 is driven into the deep side of the hole using the driving tool 172 and the hammer 173, and the tapered part 122 of the inner member 12 is relatively press-fitted into the expansion piece 112 side of the sleeve 11, and expanded by the press-fitting of the tapered part 122. The opened expansion piece 112 is inserted into the peripheral wall of the new hole 102, and the updated anchor 10 is driven into the new hole 102 (see FIGS. 3(e) and 3(f)). Note that the renewed anchor 10 of the sleeve-driving type anchor of this example has a female thread 123 formed on the inner periphery of the inner member 12, so it is usually more external than the original anchor 50 of the body-driving type anchor of this example. The diameter becomes larger.

Thereafter, as shown in FIG. 3(f), the mounting bolt 13 is screwed into the female thread 123 of the inner member 12 of the updated anchor 10, and the mounting object 152 is inserted onto the threaded mounting bolt 13, and the mounting bolt 152 is attached to the outside of the mounting object 152. Then, a washer 163 is inserted onto the mounting bolt 13 and a nut 164 is screwed onto the mounting bolt 13 to attach the fixture 152 to the concrete frame 100. This completes the replacement of the original anchor 50 with the updated anchor 10 and the installation of the attachment 152 with the updated anchor 10 according to the concrete anchor construction method of the first embodiment. Note that the attachment 151 and the attachment 152 may be the same or different.

Here, the installation conditions of the original anchor 50 and the updated anchor 10 and the expected failure of the concrete frame 100 will be explained. As shown in FIG. 4, due to its nature, concrete tends to shear failure at an angle α1=45 degrees from the tip of the cast anchor toward the surface 103 of the concrete body 100, and the maximum pullout stress of the original anchor 50 is determined by concrete failure, it is assumed that the concrete frame 100 will fracture on the illustrated cone-shaped fracture surface S1. Therefore, the stress-loaded area where the original anchor 50 that supported the attachment 151 applied tensile stress to the concrete frame 100 and had a continuous influence becomes the stress-loaded area R1 in FIG. 4.

On the other hand, the updated anchor 10, which was driven concentrically with the original anchor 50, is driven into a new hole 102 that has a larger diameter than the existing hole 101 and is deeper than the existing hole 101, as shown in FIG. If an attempt is made to shear failure from the tip of the anchor toward the surface 103 of the concrete body 100 at an angle of α2=45 degrees, and the maximum pullout stress of the updated anchor 10 is determined by the concrete failure, the concrete body 100 will have the cone shape shown in the figure. It is assumed that the rupture occurs at the expected rupture surface S2. The expected stress load area where the updated anchors 10 support the attachments 152 and tensile stress is applied to the concrete frame 100 is, in addition to the stress loaded area R1, outside the stress loaded area R1 from the expected failure surface S2. The inner region becomes a healthy region R2 where tensile stress has not been continuously applied. In other words, the renewed anchor 50 can be reliably effective by using the healthy area R2 of the concrete outside the stressed area R1 to which the original anchor 50 has applied tensile stress.

FIG. 6 shows the results of a pull-out loading test of the updated anchor 10 replaced by the concrete anchor construction method of the first embodiment and the original anchor 50 replaced by the updated anchor 10. In this pull-out loading test, a pull-out test was performed on original anchors P1, P2, and P3, which had the same configuration as the original anchor 50 cast in different locations of the concrete frame, and the applied load and displacement of the anchors were measured. The diameter D1 of the existing hole in the concrete frame in which the original anchors P1, P2, and P3 were cast is 18 mm, and the depth L1 of the existing hole 101 is 56 mm. This corresponds to the thread diameter M12.

Furthermore, after the original anchors P1, P2, and P3 were extracted by a pull-out test, holes with a diameter D2: 22.5 mm and a depth L2: New holes were formed with a diameter of 67 mm, and renewal anchors P1', P2', and P3' having the same configuration as the renewal anchor 10 were driven into each new hole. The installation positions of the updated anchors P1', P2', and P3' correspond to the original anchors P1, P2, and P3, respectively, and the updated anchors P1', P2', and P3' correspond to the thread diameter M12 of the mounting bolt 13. It is something. Then, a pullout test was performed on the installed updated anchors P1', P2', and P3', and the applied load and the displacement of the anchors were measured. As is clear from FIG. 6, by reusing the existing hole 101 concentrically to form a new hole 102 and driving the updated anchor 10 into the new hole 102, the pull-out strength and supporting force are higher than that of the original anchor 50. An update anchor 50 with a higher value can be installed.

According to the concrete anchor construction method of the first embodiment, mortar injection work for backfilling the existing hole 101 is not necessary, and the concrete anchor construction efficiency can be improved. In addition, since it is not necessary to form a new hole in a new location of the concrete frame different from the existing hole 101, the load on the concrete frame 100 can be kept to a minimum, and the strength and durability required for the concrete frame 100 can be maintained. can be maintained reliably.

Additionally, in addition to driving the updated anchor 10 into the newly drilled hole 102 which has a larger diameter than the existing hole 101, the updated anchor 10 is driven into the newly drilled hole 102 which has a deeper drilling depth than the existing hole 101. By doing so, the renewed anchor 10 can be more reliably effective by making extensive use of the healthy area R2 of the concrete outside the stressed area R1 to which the original anchor 50 has applied tensile stress.

In addition, by forming a new hole 102 concentrically with the existing hole 101 with a diameter larger than that of the existing hole 101, the existing hole 101 can be used as a pilot hole for the guide, and the new hole 102 can be straightly and concentrically formed. From this point of view, the construction efficiency of concrete anchors can be improved.

Furthermore, by making the original anchor 50 a main body driving type anchor and the updated anchor 10 a sleeve driving type anchor, the main body driving type anchor can be easily extracted and removed using, for example, an existing anchor extraction tool. . In addition, in the sleeve-driving anchor used as the updated anchor 10, the mounting bolt 13 is screwed into the internal thread 123 of the inner member 12, and when a load is applied to the mounting bolt 13, the tapered portion 122 is retracted by the expansion piece 112. Since the expansion force is generated and the anchoring force is increased, the anchoring force and supporting force of the renewal anchor 10 can be further increased.

[Construction method of concrete anchor of second embodiment]
The method for constructing a concrete anchor according to the first embodiment of the present invention is to remove the existing original anchor 50 shown in FIG. This construction method involves driving a new updated anchor 20 shown in FIG. 7 into the newly installed hole 104. Note that the configuration of the original anchor 50 is the same as in the first embodiment.

The renewal anchor 20 in FIG. 7 is an expanded-bottom type anchor, and includes a substantially cylindrical outer member 21 and a shaft body 22 inserted into the outer member 21. A slit 211 is formed in the front part of the outer member 21 and extends in the axial direction by being cut from the tip, and a plurality of slits 211 are provided at predetermined intervals in the circumferential direction. The portion between the slits 211 in the circumferential direction of the outer member 21 is an expansion piece 212, and a plurality of expansion pieces 212 are provided on the distal end side of the outer member 21 in a line in the circumferential direction. A thin part 214 that is locally bent and functions as a hinge is formed between the base cylinder 213 and the front part of the outer member 21. An extension piece 212 is provided.

The shaft body 22 has a substantially cylindrical base portion 221, a tapered portion 222 whose diameter gradually increases toward the tip is provided on the distal end side of the base portion 221, and a male thread is formed on the outer periphery on the rear end side of the base portion 221. A male threaded portion 223 is provided. The outer diameter of the base portion 221 and the male threaded portion 223 is approximately the same as or slightly smaller than the inner diameter of the base tube 213 of the outer member 21 and the inner diameter of the expansion piece 212 in a non-expanded state that is approximately the same as this. In the non-expanded state of the outer member 21, the base 221 and the male threaded portion 223 of the shaft body 22 are fitted from the expansion piece 212 of the outer member 21 to the base tube 213, and the tapered portion 222 is inserted into the base tube 213 of the outer member 21. It is arranged so that the entire body protrudes toward the tip side. Reference numeral 224 is a driving mark indicating the position where the outer member 21 is driven into the shaft body 22. When the outer member 21 is driven until the driving mark 224 is exposed from the outer member 21, the expansion piece 212 of the outer member 21 is properly aligned. It is designed to expand in different positions and states.

As shown in FIGS. 7(e) and 7(f), the updated anchor 20 is cast by placing the tapered portion 222 of the shaft body 22 on the tip side in a newly installed hole 104 having a partially enlarged diameter portion 105 in the concrete frame 100. be done. In the updated anchor 20 of the expanded bottom type anchor that has been driven, the tapered portion 222 of the shaft body 22 is relatively press-fitted into the outer member 21 side, in other words, the expansion piece 212 side by driving the outer member 21 to the back side of the hole. The expansion piece 212 expanded by press-fitting the tapered portion 222 enters the partially enlarged diameter portion 105 and is expanded. Then, the attachment 153 is inserted into the male threaded portion 223 of the shaft body 22 protruding from the surface 103 of the concrete frame 100, the washer 165 is inserted into the male threaded portion 223 from the outside of the attachment 153, and the nut 166 is screwed. A fixture 153 is attached to the concrete frame 100.

When replacing the existing original anchor 50 with the updated anchor 20 in the concrete anchor construction method of the second embodiment, for example, the original anchor 50 is driven into the existing hole 101 of the concrete frame 100, and the attachment 151 is attached. In this state, the nut 162 and washer 161 are removed from the mounting bolt 53, the attachment 151 is removed from the mounting bolt 53, and the mounting bolt 53 screwed into the main body 51 of the original anchor 50 is removed from the main body 51. Then, similarly to the first embodiment, the main body 51 and cone 52 are extracted from the existing hole 101 using the existing anchor extraction tool, and the existing original anchor 50 is extracted from the existing hole 101 and removed (see FIG. 8). (see a), (b)). In FIG. 8(b), similarly to the first embodiment, D1 is the diameter of the existing hole 101, L1 is the depth of the existing hole 101, and the depth L1 of the existing hole 101 is the depth of the outer diameter portion of the existing hole 101. It's getting dark.

Thereafter, as shown in FIG. 8(c), a hole is drilled concentrically with the existing hole 101 using a drill 174, and a new hole 104 concentric with the existing hole 101 is drilled with a diameter larger than that of the existing hole 101. Drill a hole to 100. In FIG. 8(c), D2' is the diameter of the newly installed hole 104, and the relationship is such that the diameter D2' of the newly installed hole 104>the diameter D1 of the existing hole 101.

Thereafter, as shown in FIG. 8(d), a new hole is created concentrically with the existing hole 101 using an existing partial enlarged diameter portion cutting tool 175 such as the partial enlarged diameter portion cutting tool of Patent Document 3, for example. A partially enlarged diameter portion 105 is formed in a portion of the hole 104 in the depth direction, and a new hole 104 having the partially enlarged diameter portion 105 concentric with the existing hole 101 is formed. The partially enlarged diameter portion 105 in the illustrated example is formed in a substantially tapered shape whose diameter gradually increases toward the back side of the hole. In FIG. 8(d), D3 is the maximum diameter of the partially enlarged diameter portion 105, and the relationship is such that the maximum diameter D3 of the partially enlarged diameter portion 105>the diameter D2' of the newly formed hole 104.

Next, the outer member 21 and shaft body 22 of the new updated anchor 20, which is a bottom-expanding type anchor, are inserted into the new hole 104 with the tapered portion 222 of the shaft body 22 disposed on the distal end side. Then, the outer member 21 is driven into the back of the hole using the driving tool 176 and the hammer 177, and the tapered part 222 of the shaft body 22 is relatively press-fitted to the expansion piece 212 side of the outer member 21, and the tapered part 222 is press-fitted. The expansion piece 212 is expanded to enter the partially enlarged diameter portion 105, and the renewal anchor 20 is driven into the new hole 104 having the partially enlarged diameter portion 105 (see FIGS. 8(e) and 8(f)).

Thereafter, as shown in FIG. 8(f), the attachment 153 is externally inserted into the male threaded portion 223 of the renewal anchor 20 protruding from the surface 103 of the concrete frame 100, and the washer 165 is removed from the outside of the attachment 153 to the male threaded portion 223. The attachment 153 is attached to the concrete frame 100 by inserting the nut 166 and screwing it together. This completes the replacement of the original anchor 50 with the updated anchor 20 and the installation of the attachment 153 with the updated anchor 10 according to the concrete anchor construction method of the second embodiment. Note that the attachment 151 and the attachment 153 may be the same or different.

By the way, in the type of anchor that is fixed in a straight hole, such as the updated anchor 10 of the sleeve-driving type anchor in the first embodiment described above, when a force is applied in the direction of pulling out the anchor, the expanded part of the anchor absorbs the frictional force against the concrete. try to resist with. On the other hand, in the updated anchor 20 of the expansion type anchor, the expansion piece 212 opens and enters the partially expanded diameter part 105, and when a force in the pulling direction is applied to the shaft body 22, the expansion piece 212 moves outward from the expanded expansion piece 212. Since force acts in the direction of pushing the concrete frame 100 (see FIG. 8(f) and the thick arrow in FIG. 9), a very large fixing force is developed. In the second embodiment, this force in the pushing direction is applied to the stress-loaded region R1 by the original anchor 50 and the sound region R3 outside the stress-loaded region R1 to which the tensile stress has not been continuously applied. As a result, the stress-loaded region R1 and the healthy region R3 are pressed. Normally, the concrete can withstand the pulling force without shear failure until the male threaded portion 223 of the shaft body 22 is severed.

According to the concrete anchor construction method of the second embodiment, the renewed anchor 20 is driven into the new hole 104 which is concentric with the existing hole 101 and has a partially enlarged diameter portion 105 formed in a part of the hole depth direction. By providing this, the renewed anchor 20 can be reliably effective by utilizing the sound area R3 of the concrete outside the stressed area R1 to which the original anchor 50 has applied tensile stress. Furthermore, by driving the updated anchor 20 into the newly drilled hole 104 with a diameter larger than that of the existing hole 101, the healthy area R3 of the concrete outside the stress-loaded area R1 is utilized more widely, and the updated anchor 20 can be more reliably effective.

In addition, the updated anchor 20 of the expansion type anchor opens the expansion piece 212 at the partially enlarged diameter portion 105 of the newly installed hole 104, and when a force in the pulling direction is applied to the shaft body 22, the expansion piece 212 is opened outward from the expanded expansion piece 212. Since the force acts in the direction of pushing the concrete, a very large anchoring force is developed, and the anchoring force and supporting force of the renewal anchor 20 can be further increased. In addition, the second embodiment can obtain corresponding effects from the configuration corresponding to the first embodiment.

[Scope of coverage of the invention disclosed herein]
In addition to each invention and each embodiment listed as an invention, the invention disclosed in this specification is specified by changing the partial contents of these to other contents disclosed in this specification to the extent applicable. , or specified by adding other contents disclosed in this specification to these contents, or specified by deleting these partial contents to the extent that partial effects can be obtained and converting them into a general concept. includes. The invention disclosed in this specification also includes the following contents and modifications.

For example, in the first embodiment, a new hole 102 that is concentric with the existing hole 101 is drilled in the concrete frame 100 with a diameter larger than that of the existing hole 101 and a drilling depth that is deeper than the existing hole 101. However, a new hole 102 is drilled in the concrete frame 100 with a diameter larger than the existing hole 101 and concentric with the existing hole 101. A configuration in which the updated anchor 10 is driven into the hole 102, or a new hole 102 that is concentric with the existing hole 101 is drilled in the concrete frame 100 with a drilling depth deeper than the existing hole 101, and this new hole 102 is It is also suitable as a configuration for driving the updated anchor 10, and thereby the updated anchor 10 can be reliably effective by utilizing the healthy area of the concrete outside the area R1 where stress has been applied by the original anchor 50.

In addition, in the second embodiment, a new hole 104 having a partially enlarged diameter portion 105 in a part of the hole depth direction was formed with a diameter larger than that of the existing hole 101, but a new hole having the same diameter as the existing hole 101 104 (that is, by using the original existing hole 101 as it is), a partially enlarged diameter portion 105 is formed in a part of the hole depth direction, and an existing hole having a partially enlarged diameter portion 105 in a part of the hole depth direction. Even if the renewal anchor 20 is driven into the new hole 104 having the same diameter as the hole 101, the renewal anchor 20 can be reliably effective as in the second embodiment, which is good. In addition, a new hole 104 having the same diameter as the existing hole 101 having a partially enlarged diameter portion 105 in a part of the hole depth direction, or a new hole 104 having a diameter larger than the existing hole 101 having a partially enlarged diameter portion 105 in a part of the hole depth direction. The new hole 104 may be formed with a deeper drilling depth than the existing hole 101, and the renewal anchor 20 may be driven into the new hole 104 formed in this way. This is good because the anchor 20 can be made to work reliably.

In addition, the original anchor and the renewed anchor in the present invention are appropriate within the scope to which the present invention can be applied, and the present invention is also applicable to original anchors other than main body driving type anchors. The present invention is also applicable to update anchors other than built-in anchors and expanded-bottom anchors. For example, the present invention can be applied to the case where the original anchor of the main body driving type anchor is replaced with an updated anchor of the main body driving type anchor.

INDUSTRIAL APPLICATION This invention can be utilized when removing the existing anchor installed in the concrete frame and replacing with a new anchor.

10, P1', P2', P3'...Updated anchor 11...Sleeve 111...Slit 112...Expansion piece 113...Irregularity 114...Rear part 12...Inner member 121...Base 122...Tapered part 123...Female thread 13...Mounting bolt 20...Update Anchor 21...Outer member 211...Slit 212...Expansion piece 213...Base cylinder 214...Thin wall part 22...Shaft body 221...Base 222...Tapered part 223...Male thread part 224...Drive mark 50, P1, P2, P3...Original anchor 51...Body 511...Female thread 512...Slit 513...Expanding piece 514...Irregularity 52...Cone 521...Base 522...Tapered part 53...Mounting bolt 100...Concrete frame 101...Existing hole 102...New hole 103...Surface 104...New hole 105...Partial enlarged diameter part 151, 152, 153...Attachment 161, 163, 165...Washer 162, 164, 166...Nut 171, 174...Drill 172, 176...Driver 173, 177...Hammer 175...Partial diameter enlargement Part cutting tool 300... Concrete frame 301... Existing hole 302... Mortar 303... New hole D1... Diameter of existing hole, L1... Depth of existing hole D2, D2'... Diameter of new hole L2... Depth of new hole D3 ...Maximum diameter of the partially enlarged diameter part α1...Inclination angle of the assumed failure surface of the original anchor S1...Supposed failure surface R1...Stress loaded area α2...Inclination angle of the assumed failure surface of the updated anchor S2...Supposed failure surface R2...Sound area R3...Sound area to be pressed S10...Fracture assumed surface R10...Stress loaded area

Claims (6)

The first step is to extract the existing original anchor from the existing hole in the concrete frame;
a second step of drilling a new hole concentrically with the existing hole with a diameter larger than the existing hole;
A third step of driving a new renewal anchor into the newly installed hole ,
The original anchor has a main body in which a female thread into which a mounting bolt is screwed is formed on the inner periphery and an expanding piece is formed on the distal end side, and the main body is press-fitted from the distal end side into the main body side to expand the expanding piece. It is a main body driving type anchor consisting of a cone,
The renewal anchor includes an inner member provided with a tapered portion that gradually increases in diameter toward the distal end on the distal end side of the base, and a female thread formed on the inner periphery of the base to which a mounting bolt is screwed; A method for constructing a concrete anchor, characterized in that the anchor is a sleeve-driving type anchor comprising a sleeve provided with an expansion piece that expands by press-fitting a tapered part . 2. The method for constructing a concrete anchor according to claim 1, wherein in the second step, the new hole is drilled to a depth that is deeper than the existing hole. The first step is to extract the existing original anchor from the existing hole in the concrete frame;
a second step of drilling a new hole concentrically with the existing hole at a drilling depth that is deeper than the existing hole;
A third step of driving a new renewal anchor into the newly installed hole ,
The original anchor has a main body in which a female thread into which a mounting bolt is screwed is formed on the inner periphery and an expanding piece is formed on the distal end side, and the main body is press-fitted from the distal end side into the main body side to expand the expanding piece. It is a main body driving type anchor consisting of a cone,
The renewal anchor includes an inner member provided with a tapered portion that gradually increases in diameter toward the distal end on the distal end side of the base, and a female thread formed on the inner periphery of the base to which a mounting bolt is screwed; A method for constructing a concrete anchor, characterized in that the anchor is a sleeve-driving type anchor comprising a sleeve provided with an expansion piece that expands by press-fitting a tapered part . The first step is to extract the existing original anchor from the existing hole in the concrete frame;
a second step of drilling a new hole by forming a partially enlarged diameter portion in a depth direction of the hole concentrically with the existing hole;
A method for constructing an anchor for concrete, comprising a third step of driving a new updated anchor into the new hole by inserting an enlarged expansion piece into the partially enlarged diameter portion. In the second step, the new hole is drilled with a diameter larger than that of the existing hole, or the new hole is drilled with a drilling depth that is deeper than the existing hole, or the new hole is drilled with a drilling depth that is deeper than the existing hole. 5. The method for constructing a concrete anchor according to claim 4 , wherein the new hole is drilled with a larger diameter and a deeper hole depth than the existing hole. The original anchor has a main body formed with a female thread on the inner periphery into which a mounting bolt is screwed and an expansion piece formed on the distal end side, and a cone press-fitted into the main body by driving the main body. It is a built-in anchor,
The renewal anchor includes a shaft body provided with a tapered part that gradually increases in diameter toward the distal end of the base, and a male screw part provided with the rear end of the base, and a thin wall part on the distal end of the base tube. 6. The method of constructing a concrete anchor according to claim 4, wherein the anchor is an expanding-bottom type anchor comprising an outer member provided with an expansion piece that expands when the tapered portion is press-fitted through the outer member.

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