JP6371522B2 - How to remove the sole plate - Google Patents

Description

  The present invention relates to a method of removing a sole plate for removing a sole plate welded to a lower flange of a bridge girder of a bridge, and more particularly, a sole capable of safely and quickly removing a sole plate without damaging the lower flange. It relates to the removal method of the plate.

  Many bridges manufactured during the period of high economic growth have been over 50 years old and have to be repaired to cope with rust and cracks. In addition, repair work is underway to reinforce the bridge so that it can respond to a major earthquake. Thus, there are a large number of repair points necessary for bridges nationwide, and repair work is being carried out at a rapid pace in recent years. For this reason, how to perform this repair work efficiently and at low cost is a very important issue.

  For example, in the bridge to be repaired, as shown in FIG. 9, the sole plate 10 is disposed below the lower flange 1 a of the bridge girder 1 and supported by the pier 3 via the support 2. When the load is transmitted from the bridge girder 1 to the support 2 by the sole plate 10, the flow of the load is made smooth and the stress concentration is eased. The sole plate 10 is joined to the lower flange 1a of the bridge girder 1 by fillet welding on the entire circumference, and receives a load due to traveling of the vehicle or the like.

  In the sole plate 10, a bead 10 a is formed at the edge of the entire circumference, and the bonding strength is ensured. However, since the bridge receives a large load every time a vehicle or the like passes over a long period of time, there is a problem in that a large compressive load and a tensile load act repeatedly on the bead 10a to cause a crack due to fatigue. If the bead 10a has a crack, the crack grows and becomes larger, which may lead to the destruction of the bridge girder 1. Therefore, recently, in order to prevent the bead 10a from cracking, the old sole plate 10 is removed from the lower flange 1a and replaced with a new sole plate. The new sole plate is joined to the lower flange 1a via a high-strength bolt.

  Here, FIG. 10 is a view for explaining a method of removing the sole plate 10 from the lower flange 1a in the conventional method. As shown in FIG. 10, the operator manually operates the grinder 20 and presses the radially outer end 21 a of the rotating grinding blade 21 against the bead 10 a of the sole plate 10. Thereby, the bead 10a is gradually ground, and the sole plate 10 is separated from the lower flange 1a by cutting the bead 10a.

  Patent Document 1 below describes that the bead 10a of the sole plate 10 is cut using a cutting device that moves a disc grinder. As shown in FIG. 9, this cutting device 200 has a disc grinder 210 mounted on an XY table (not shown), and the grinding blade 211 of the disc grinder 210 can be moved in the horizontal direction by the XY table. As a result, the grinding blade 211 moves in the plane direction (horizontal direction) with respect to the joint surface of the bead 10a to be joined to the lower flange 1a, so that the sole plate 10 is separated from the lower flange 1a.

JP 2004-346518 A

  However, the conventional method for removing the sole plate has the following problems. First, when the operator manually operates the grinder 20, the work must be performed upward at a high place on the upper side of the pier 3 and in a narrow narrow portion 4 (see FIG. 9) between the bridge girder 1 and the pier 3. Don't be. For this reason, the operation of the grinder 20 is difficult. Therefore, there is a possibility that the grinding blade 21 enters obliquely toward the lower flange 1a and damages the lower flange 1a. Further, operating the relatively heavy grinder 20 upward in the narrow portion 4 consumes a great deal of the physical strength of the worker, and the safety of the work is not high. Furthermore, the operation of gradually grinding the bead 10a with the grinding blade 21 takes a lot of time, and there is a large variation in the time during which the bead 10a can be removed according to the skill of the worker.

  On the other hand, if the cutting device 200 described in Patent Document 1 is used, the grinding blade 211 of the disc grinder 210 is moved in the plane direction (horizontal direction) along the lower flange 1a, so that the lower flange 1a is damaged. Can be prevented. In addition, work safety can be improved. However, this cutting apparatus 200 also has a problem that it takes a lot of time to grind the bead 10a because the bead 10a is gradually ground by the grinding blade 211, and the working efficiency is not good. Furthermore, there are the following problems.

  That is, even if the grinding blade 211 is moved in the plane direction along the lower flange 1a, as shown in FIG. 11, the thin skin portion 10g remains between the grinding groove 10f formed by grinding and the lower flange 1a. End up. This is because when the disc grinder 210 moves the rail member of the XY table, the position of the grinding blade 211 is slightly lowered from the correct position due to the deflection of the rail member and the gravity acting on the cutting device 200. Thus, if any thin skin portion 10g remains, the sole plate 10 remains joined to the lower flange 1a.

  Therefore, it is conceivable that after the thin skin portion 10g is formed, the operator manually operates the grinder 20 and grinds the thin skin portion 10g with the grinding blade 21 to remove the thin skin portion 10g. However, since the thickness dimension of the grinding blade 211 when forming the grinding groove 10f is about 1 to 2 mm and is thin (see paragraph 0023 of Patent Document 1 above), the width dimension U2 of the grinding groove 10f is also about 1 to 2 mm. become. For this reason, even if an operator tries to grind the thin skin part 10g remaining with the grinding blade 21 of the grinder 20, the innermost inner joint end z1 joined to the lower flange 1a of the bead 10a cannot be visually recognized. As a result, it is very difficult to reliably and quickly remove the thin skin portion 10g. Furthermore, the grinding blade 21 may be caught in the grinding groove 10f having a narrow width of about 1 to 2 mm, and the behavior of the grinder 20 may become unstable, which may be dangerous.

  Therefore, the present invention has been made to solve the above-described problems, and while ensuring work safety, work quality and work time can be stabilized, and construction efficiency can be improved. It aims at providing the removal method of a soleplate.

  The sole plate removing method according to the present invention is such that the sole plate is fillet welded to the lower flange of the bridge girder, and the bead formed on the edge of the sole plate is cut to remove the sole plate from the lower flange. A cutting method formed by cutting using a cutting device having a disk-shaped cutting blade to move the cutting blade in a plane direction along the lower flange while rotating the cutting blade. A thin skin portion is formed between the groove and the lower flange so that an innermost inner joint end joined to the lower flange of the beads can be visually recognized, and the thin skin portion is removed while visually checking the inner joint end. It is characterized by doing.

  According to the method for removing the sole plate according to the present invention, since the bead is cut with the cutting blade of the cutting device instead of grinding the bead, the time until the cutting groove is formed is relatively short. Since the cutting groove is formed by moving the relatively thick cutting blade in the plane direction along the lower flange, the width dimension of the cutting groove is relatively large. Thereby, a thin skin part is formed so that the inner side joining edge of a bead can be visually recognized. For this reason, when an operator grinds a thin skin part with the grinding blade of a grinder, for example, since the inner joint edge of a bead can be visually recognized, a thin skin part can be removed reliably and quickly. Furthermore, since the width dimension of the cutting groove is relatively large, the grinding blade does not bite into the cutting groove, and there is no risk that the behavior of the grinder becomes unstable. Thus, the work quality and the work time can be stabilized while ensuring the safety of the work, and the construction efficiency can be improved.

Moreover, in the removal method of the sole plate which concerns on this invention, it is good to form the said cutting groove with the cutting blade whose thickness dimension is 5 mm or more and smaller than 8 mm.
In this case, when the cutting edge has a thickness dimension of 5 mm or more, the inner joint end of the bead can be surely visually recognized when the thin skin portion is formed. On the other hand, when the thickness of the cutting blade is 8 mm or more, the cutting device that rotationally drives the cutting blade increases in size. Thereby, the weight of a cutting device becomes large and the operation | work which an operator lifts a cutting device becomes difficult. Thus, if a cutting blade having a thickness dimension of 5 mm or more and smaller than 8 mm is used, the present invention can be more suitably implemented.

Further, in the method for removing the sole plate according to the present invention, the cutting blade includes a plurality of blades formed at equal intervals in the circumferential direction at the radially outer end portions, and an upper surface side and a lower surface side in the circumferential direction. It is preferable that the cutting groove is formed by the zigzag blade side cutter.
In this case, the staggered side cutter has high cutting ability and is suitable for deep groove processing, and therefore, a cutting groove having a relatively wide width can be optimally formed.

  According to the method for removing the sole plate of the present invention, the cutting blade is moved in the plane direction along the lower flange using the cutting device, so that the lower flange is not damaged. And since a thin skin part can be removed visually recognizing the inner joint edge of a bead, work quality and work time can be stabilized irrespective of a worker's skill. Furthermore, the cutting groove can be formed quickly by the cutting blade, and the thin skin portion can be removed quickly by visually recognizing the inner joint end of the bead, so that the construction efficiency can be improved and the construction cost is greatly reduced compared to the conventional case. Can do.

(A) It is the bottom view which showed the sole plate welded to the lower flange of the bridge girder. (B) It is sectional drawing which followed the XX line of FIG. 1 (A). It is the perspective view which showed the cutting device of this embodiment. It is a front view of the cutting apparatus shown in FIG. It is a top view of the cutting device shown in FIG. (A) It is an enlarged view of the cutting blade shown in FIG. (B) It is a side view of the cutting blade shown in FIG. It is the figure which showed the state in which the cutting groove was formed in the bead. It is the figure which showed the state from which the thin skin part of the bead was removed. (A) It is a top view of the cutting blade of a modification. (B) It is a side view of the cutting blade of the modification shown to FIG. 8 (A). It is the figure which showed the state by which the bead of a soleplate is cut | disconnected by the conventional cutting device. It is a figure for demonstrating the method of removing a sole plate from a lower flange in the conventional method. It is the figure which showed the state which cannot visually recognize the inner side joining end of a bead.

  An embodiment of a method for removing a sole plate according to the present invention will be described with reference to the drawings. FIG. 1A is a bottom view showing the sole plate 10 that is fillet welded to the lower flange 1 a of the bridge girder 1. The sole plate 10 is a rectangular and flat steel plate, and is fillet welded to the lower flange 1a of the bridge girder 1 by arc welding on the entire circumference (see FIG. 9). For this reason, as shown to FIG. 1 (A), bead 10a is formed in each long side edge part 10A, 10B and each short side edge part 10C, 10D of the soleplate 10, respectively. Here, FIG. 1B is a cross-sectional view taken along line XX of FIG.

  As shown in FIG. 1 (B), the bead 10a is melted to the inner side (left side of FIG. 1 (B)) from the long side edge portion 10A and has a substantially triangular cross section. The height dimension T1 between the lower flange 1a and the lowest end x1 of the bead 10a is about 8 mm. Further, the width dimension S1 between the outer joint end y1 that joins the lower flange 1a on the outermost side of the bead 10a and the long side edge portion 10A is about 8 mm. Further, the width dimension S2 between the inner joint end z1 that joins the lower flange 1a on the innermost side of the bead 10a and the long side edge portion 10A is about 5 mm. Thus, the long side edge portion 10A and the lower flange 1a are joined by about 13 mm which is the width dimension (S1 + S2) between the outer joint end y1 and the inner joint end z1 of the bead 10a. The bead 10a formed on the long side edge portion 10A is the same as the bead 10a formed on the other long side edge portion 10B and the short side edge portions 10C and 10D, and thus the description thereof is omitted.

  By the way, if a crack due to fatigue occurs in the bead 10a, the crack grows and becomes large, which may lead to destruction of the bridge girder 1. For this reason, in order to prevent the bead 10a from cracking, the old sole plate 10 is removed from the lower flange 1a as a bridge repair work. Thereafter, a new sole plate is joined to the lower flange 1a using a high-strength bolt. Here, conventionally, when the sole plate 10 is removed from the lower flange 1a, the bead 10a is cut using the grinder 20 (see FIG. 10).

  However, as described in the problem to be solved by the invention, the work of cutting the bead 10a with the grinder 20 takes a lot of time. This is because the grinding blade 21 of the grinder 20 grinds the bead 10a, that is, scrapes off gradually. And the operation | work which operates the grinder 20 upwards in the narrow part 4 (refer FIG. 9) consumes a worker's physical strength largely, and is not high safety | security. On the other hand, even if the cutting device 200 shown in FIG. 9 is used, the thin skin portion 10g remains as shown in FIG. In this case, even if the operator manually operates the grinder 20 and tries to grind the thin skin portion 10g with the grinding blade 21, the inner joint end z1 of the bead 10a cannot be visually recognized. For this reason, it is very difficult to reliably and quickly remove the thin skin portion 10g. Furthermore, the grinding blade 21 may be caught in the thin grinding groove 10f and the behavior of the grinder 20 may become unstable.

  Therefore, the above-described problems can be solved by the method for removing the sole plate of the present embodiment. Here, first, the cutting apparatus 100 used in the present embodiment will be described. 2 is a perspective view showing the cutting device 100 of the present embodiment, FIG. 3 is a front view of the cutting device 100 shown in FIG. 2, and FIG. 4 is a plan view of the cutting device 100 shown in FIG. is there. As shown in FIGS. 2 to 4, the cutting apparatus 100 mainly includes a holding plate 110, a rail member 120, a screw rod 130, an electromagnet 140, an electric motor 150, and a T-shaped cutting tool 160. It is configured.

  The holding plate 110 is a rectangular and flat steel plate, and serves as a base for the cutting apparatus 100. Standing support members 111 are provided at both ends of the holding plate 110. Further, as shown in FIG. 3, a jack point 110 a that serves as a mark when supported by the jack 5 is provided on the lower surface of the holding plate 110. In this way, each jack 5 is supported by each jack point 110a, so that the cutting device 100 can be held in a correct posture.

  Two rail members 120 are attached in parallel to the upper side of the holding plate 110 and extend in the longitudinal direction of the holding plate 110. Hereinafter, the longitudinal direction of the holding plate 110 is simply referred to as “longitudinal direction”. A flat base 121 is provided above each rail member 120, and the base 121 is slidably attached to each rail member 120 via each locking member 122.

  As shown in FIG. 4, the screw rod 130 extends in the longitudinal direction between the rail members 120, and is rotatably supported by the support member 111 via bearings 131 at both ends. A rotating handle 132 is attached to one end portion (right end portion in FIG. 3) of the screw rod 130, and a male screw is formed on the peripheral surface of the screw rod 130. An engaging member (not shown) is fixed to the lower side of the base 121, and a female screw formed on the engaging member and a male screw formed on the screw rod 130 are screwed together. Thus, when the rotary handle 132 is rotated, the screw rod 130 is rotated, and the base 121 can be moved along the rail members 120 in the longitudinal direction.

  The electromagnets 140 are respectively provided above the four corners of the holding plate 110, and are attached to the holding plate 110 via support bars 141 extending in the vertical direction. These electromagnets 140 generate or extinguish electromagnetic force when the switch 142 is turned on or off. For this reason, when the switch 142 is turned on in a state where each electromagnet 140 is in contact with the lower flange 1a, each electromagnet 140 is attracted to the lower flange 1a by electromagnetic force, and the cutting device 100 can be attached to the lower flange 1a. .

  The electric motor 150 rotates the T-shaped cutting tool 160 by operating a switch (not shown). The electric motor 150 includes a rectangular parallelepiped body portion 151 attached to the upper side of the base 121 and a hollow cylindrical attachment portion 152 attached to the upper side of the body portion 151. As shown in FIG. 3, the attachment portion 152 accommodates the shaft portion 162 of the T-shaped cutting tool 160 therein.

  The T-shaped cutting tool 160 cuts the bead 10a. As shown in FIG. 3, the T-shaped cutting tool 160 has a disk-shaped cutting blade 161 on the upper side and a shaft portion 162 on the lower side. 5A is an enlarged view of the cutting blade 161 shown in FIG. 4, and FIG. 5B is a side view of the cutting blade 161 shown in FIG. As shown in FIG. 5 (A), the cutting blade 161 has a plurality of blades 161c and 161d at the radially outer ends, and a V-shaped chip pocket 161e on the front side in the rotational direction (counterclockwise direction). Have. The blades 161c and 161d are arranged at equal intervals in the circumferential direction.

  5B, the blade 161c is formed on the upper surface 161a side (right side of FIG. 5B) of the cutting blade 161, and the blade 161d is formed on the lower surface 161b side of the cutting blade 161 (FIG. 5). (Left side of (B)). Each blade 161c and each blade 161d are provided with their directions alternately changed on the upper surface 161a side and the lower surface 161b side in the circumferential direction. Thus, the cutting blade 161 is a so-called staggered side cutter, which has a high cutting ability and is suitable for deep groove processing. The thickness K1 of the cutting blade 161 is set to 5 mm. Thus, since the cutting blade 161 is a staggered blade side cutter, a relatively wide cutting groove 10b (see FIG. 6) can be optimally formed as will be described later. And when forming the cutting groove 10b, each blade 161c, 161d can be alternately involved in the wall surface of the cutting groove 10b, and the deformation | transformation of the cutting blade 161 can be suppressed.

  As shown in FIG. 3, the shaft portion 162 is non-rotatably attached to the attachment portion 152 using a key member (not shown). A spring member 163 is interposed between the lower end of the shaft portion 162 and the bottom portion of the attachment portion 152. By this spring member 163, the cutting blade 161 is urged upward so that the upper surface 161a of the cutting blade 161 is pressed in a state of surface contact with the lower flange 1a. Further, a bolt 164 extending in the radial direction (left-right direction in FIG. 3) is attached to the attachment portion 152. By this bolt 164, the shaft portion 162 is pressed into the mounting portion 152, and the radial position of the shaft portion 162 is fixed. A nut 165 is screwed onto the bolt 164 to prevent loosening due to vibration of the bolt 164 when the cutting blade 161 is cut.

  Next, a procedure for removing the sole plate 10 using the cutting device 100 configured as described above will be described. First, the bridge girder 1 is provisionally received by a jack (not shown) supported by the pier 3 to secure a work space. And as shown in FIG. 3, the holding plate 110 is supported by each jack 5, and the height of the cutting device 100 is adjusted. At the same time, the screw rod 130 and the rail member 120 are arranged in parallel to the long side edge portion 10A of the sole plate 10, and alignment for cutting the bead 10a formed on the long side edge portion 10A is performed. Thereafter, each electromagnet 140 is attracted to the lower flange 1a, and the upper surface 161a of the cutting blade 161 is pressed against the lower flange 1a.

  Then, the T-shaped cutting tool 160 is rotated, and the rotary handle 132 is rotated to move the cutting blade 161, the electric motor 150, and the base 121 along the rail members 120 in the longitudinal direction. The moving speed of the cutting blade 161 is about 2 cm / min. Thereby, the rotating cutting blade 161 cuts the bead 10a along the lower flange 1a, and the cutting groove 10b is formed in the bead 10a as shown in FIG. Here, since the width dimension (S1 + S2) between the outer joint end y1 and the inner joint end z1 of the bead 10a is about 13 mm as described above, in this embodiment, the width dimension W1 of the cutting groove 10b is 13 mm. Cut to the above. Since the thickness dimension K1 of the cutting blade 161 is 5 mm as described above, the width dimension U1 of the cutting groove 10b is 5 mm.

  At the time of this cutting, as shown in FIG. 6, a thin skin portion 10c is formed between the cutting groove 10b and the lower flange 1a. The thin skin portion 10 c is formed by slightly lowering the position of the cutting blade 161 from the correct position due to the deflection of the rail member 120 and the gravity acting on the cutting device 100. However, in this embodiment, since the wide cutting groove 10b whose width dimension U1 is 5 mm is formed, the inner joint end z1 of the bead 10a can be visually recognized.

  Thus, after the cutting of the bead 10a formed on the long side edge portion 10A is completed, the mounting position of the cutting device 100 on the lower flange 1a is changed, and the bead 10a formed on the long side edge portion 10B and each short edge The bead 10a formed in the portions 10C and 10D is similarly cut. Thereafter, the operator manually operates the grinder 20 (see FIG. 10), and grinds the thin skin portion 10c with the grinding blade 21 while visually recognizing the inner joint end z1 of the bead 10a. Accordingly, as shown in FIG. 7, the thin skin portion 10c is removed, and the sole plate 10 is not joined to the lower flange 1a. In this way, removal of the sole plate 10 is completed.

The effect of this embodiment is demonstrated.
According to the method for removing the sole plate of the present embodiment, the bead 10a is not ground by the grinding blade 21 of the grinder 20 to form the grinding groove 10f (see FIG. 11) as in the prior art. The bead 10a is cut with the blade 161 to form the cutting groove 10b. For this reason, the time until the cutting groove 10b is formed is relatively short. And since the cutting blade 161 is moved to a plane direction along the lower flange 1a using the cutting device 100, the lower flange 1a is not damaged.

  In particular, in the present embodiment, a relatively wide cutting groove 10b is formed using a relatively thick cutting blade 161. Thereby, the thin skin part 10c is formed so that the inner side joining edge z1 of the bead 10a can be visually recognized. For this reason, when grinding the thin skin part 10c with the grinding blade 21 of the grinder 20 after that, it can remove, visually recognizing the inner side joining edge 1z of the bead 10a. Accordingly, the thin skin portion 10c can be reliably and quickly removed. Thus, the cutting groove 10b can be quickly formed by the cutting blade 161, and the thin skin portion 10c can be quickly removed by visually recognizing the inner joint end z1 of the bead 10a, so that the construction efficiency can be improved. As a result, the construction cost can be greatly reduced as compared with the conventional case.

  In addition, since the cutting groove 10b is formed only by moving the cutting blade 161 using the cutting device 100, it can be easily performed even by a worker who has relatively little experience. Even in the operation of removing the thin skin portion 10c, since the width dimension U1 (5 mm) of the cutting groove 10b is relatively large, the grinding blade 21 does not bite into the cutting groove 10b. Therefore, there is no risk that the behavior of the grinder 20 becomes unstable. In this way, work safety is high and work quality and work time can be stabilized regardless of the skill of the worker.

  Here, in this embodiment, the reason for using the cutting blade 161 whose thickness dimension K1 is 5 mm is based on the following. That is, if the cutting blade 161 has a thickness dimension K1 of 5 mm, the inner joint end z1 of the bead 10a can be reliably recognized when the thin skin portion 10c is formed. Therefore, it is considered that the larger the thickness dimension K1, the better. However, if a cutting blade having a thickness dimension K1 of 8 mm or more is used, a cutting device that rotationally drives the cutting blade becomes large. Thereby, the weight of a cutting device becomes large and the operation | work which an operator lifts a cutting device becomes difficult. The weight of the cutting device 100 that rotationally drives the cutting blade 161 of this embodiment is about 60 kg. Thus, it is preferable to use a cutting blade having a thickness dimension K1 of 5 mm or more and smaller than 8 mm from the viewpoint of visually recognizing the inner joint end z1 and the weight of the cutting device 100.

  As can be seen from the above description, in this embodiment, when forming the cutting groove 10b, it is not a technical idea to eliminate the thin skin portion 10c as much as possible, and it is assumed that the thin skin portion 10c remains, and the inner joint of the bead 10a remains. It has an unprecedented technical idea of cutting so that the end z1 can be visually recognized. And the effect of the removal method of the sole plate of this embodiment mentioned above appears more remarkable, so that the sole plate 10 is joined more firmly by the bead 10a.

As mentioned above, although the removal method of the sole plate which concerns on this invention was demonstrated, this invention is not limited to this embodiment, A various change is possible in the range which does not deviate from the meaning.
In this embodiment, the staggered blade side cutter is used as the cutting blade 161, but the cutting blade is not limited to the staggered blade cutter. For example, as shown in FIGS. 8A and 8B, each of the blades 161c formed at the radially outer end may be a normal side cutter that is orthogonal to the upper surface 161a and the lower surface 161b. Moreover, you may use the side cutter which is the throw away tip which each blade can attach or detach.
In the present embodiment, the thin skin portion 10c is removed by grinding with the grinder 20. However, the method for removing the thin skin portion 10c can be changed as appropriate. For example, the thin skin portion 10c is removed using a driving arrow and a hammer. You may do it.
In addition, the dimensions S1 (8 mm), S2 (5 mm), T1 (8 mm), K1 (5 mm), and W1 (13 mm or more) described in the present embodiment are merely examples, and can be appropriately changed. is there.

DESCRIPTION OF SYMBOLS 1 Bridge girder 1a Lower flange 10 Sole plate 10a Bead 10b Cutting groove 10c Thin skin part 20 Grinder 100 Cutting device 110 Holding plate 120 Rail member 130 Screw rod 140 Electromagnet 150 Electric motor 160 T type cutting tool 161,166 Cutting blade 161a Upper surface 161b Lower surface 161c, 161d, 166c blade y1 outer joint end z1 inner joint end

Claims (3)

In the method of removing the sole plate, the sole plate is welded to the lower flange of the bridge girder, and the bead formed on the edge of the sole plate is cut to remove the sole plate from the lower flange.
Using a cutting device having a disk-shaped cutting blade having a thickness such that the inner joint end of the bead can be surely recognized when forming a thin skin portion, a plane is formed along the lower flange while rotating the cutting blade. The thin skin portion so that the innermost inner joint end joined to the lower flange of the beads can be visually recognized between the cut groove formed by cutting and the lower flange. Form the
A method for removing a sole plate, wherein the thin skin portion is removed while visually checking the inner joint end. The method for removing a sole plate according to claim 1,
A method for removing a sole plate, wherein the cutting groove is formed by a cutting blade having a thickness dimension of 5 mm or more and smaller than 8 mm. In the method for removing the sole plate according to claim 1 or 2,
The cutting blade is a staggered blade side in which a plurality of blades formed at equal intervals in the circumferential direction at radially outer ends are alternately changed in the direction of the upper surface side and the lower surface side in the circumferential direction. A cutter,
The method of removing a sole plate, wherein the cutting groove is formed by the staggered side cutter.

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