Method for fixing the base of a building column and washer for the column base fixing structure

Abstract

This invention provides a method for fixing the base of a building column, which involves filling the space below the base plate with grout, as well as the space between the anchor bolts and the holes for the anchor bolts. [Solution] This method for fixing the column base of a building involves injecting grout G into the space below the base plate 21 of the column base 2 located above the foundation 1, and also filling the space between the anchor bolt 11 protruding from the foundation 1 and the anchor bolt hole 21a, which is an oversized hole formed in the base plate 21, with grout G from the grout filling section 61 of the filling frame 6. Then, the filled grout G is allowed to overflow from a notch 3b in at least one washer 3 that is connected to the bolt insertion hole 3a of the washer 3 and has an open edge, and additional grout G is injected into the notch 3b of the washer 3 in the area where the filled grout G did not overflow.

Description

Technical Field

[0001] This invention relates to a method for fixing a building column base and a washer for a column base fixing structure.

Background Art

[0002] Conventionally, in order to accurately transmit the shear force caused by an earthquake or wind from a base plate in which an anchor bolt hole is formed as an oversized hole to the anchor bolt, a washer with an appropriate hole is fitted onto the anchor bolt at the site, and the periphery of the washer is welded to the base plate. As a technique for eliminating such on-site welding, a method has been proposed in which grout injected into the space below the base plate is also filled between the anchor bolt and the anchor bolt hole.

[0003] Patent Document 1 discloses a method for fixing a column base in a steel column base of a building, in which the upper part of an anchor bolt buried in a lower part in a foundation concrete is inserted through bolt holes of a base plate and a washer at the lower part of the column base, and after installing by screwing a nut onto the anchor bolt, grout is filled in the gap between the upper surface of the foundation and the lower surface of the base plate to integrally fix the column base. In the injection holes provided in advance, a plug body or a cylindrical body having a through hole in the central part is fitted into the opening of the injection hole near the injection hole used for injection before filling the grout, and then the grout is filled. On the back surface side of the washer, an injection port and a concave groove for injecting grout into the space below the base plate are formed.

[0004] Patent Document 2 discloses an exposed column base anchoring structure in which, in addition to an oversized hole for inserting an anchor bolt in a base plate fixed to the lower end of a steel column, a leg portion provided on the lower surface of a washer is fitted from the upper side, and with the anchor bolt protruding from the surface of the foundation concrete inserted into the washer, the anchor bolt is tightened from above with a nut that screws onto the anchor bolt, and the steel column is fixed to the foundation concrete by filling the lower surface of the base plate with grout, wherein the length of the leg portion of the washer is smaller than the thickness of the base plate, and the inside of the oversized hole below the leg portion is filled with the grout that has penetrated to the lower side of the base plate. The washer has a nesting structure.

[0005] Patent Document 3 discloses a column base fixing structure that facilitates and reduces the cost of grout injection after nut fastening. This column base fixing structure comprises an anchor bolt fixed to the foundation concrete, a base plate having an anchor bolt through-hole through which the anchor bolt passes, a column base whose lower end is fixed to the base plate, an upper nut that screws onto the anchor bolt as it passes through the anchor bolt through-hole and fastens the base plate by pressing it against the side where the foundation concrete is located, and a washer having an assembly hole through which the anchor bolt passes and being sandwiched between the upper nut and the base plate. The washer is provided on the fastening surface that contacts the upper nut or the base plate and has a groove that extends from the outer circumference of the washer in the direction of the assembly hole. This groove communicates with the gap between the anchor bolt and the anchor bolt through-hole. Furthermore, a filling frame surrounding the base plate is installed on the upper surface of the foundation concrete, and grout is injected inside this filling frame to form base plate underfill grout. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 2898786 [Patent Document 2] Japanese Patent Publication No. 2020-16104 [Patent Document 3] Patent No. 6284603 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, the technology described in Patent Document 1 has the disadvantage of high washer costs because the washer has an injection port and groove formed therein for injecting grout into the space below the base plate. Also, if all of the grout is injected through the washer's injection port, the time required for this injection becomes long.

[0008] The technology described in Patent Document 2 has the drawback of high washer costs because the washers have a nested structure. In addition, since the filling frame is placed at a position spaced apart from the periphery of the base plate and the grout is poured through the gap between the base plate and the filling frame, a separate process is required to apply pressure to the grout in the gap.

[0009] In the technology described in Patent Document 3, the part into which the grout formed in the washer is injected is the groove, which helps to keep the cost of the washer down, but if all of the grout is injected from the groove of the washer, the time required for this injection becomes longer.

[0010] The object of this invention is to provide a method for fixing the base of a building column and a washer for a column base fixing structure that allows for rapid additional grout injection to areas where the grout between the anchor bolt and the anchor bolt hole is insufficiently filled, in a method in which grout is injected into the space below the base plate and also fills the space between the anchor bolt and the hole for the anchor bolt. [Means for solving the problem]

[0011] The present invention provides a method for fixing the base of a building column in order to solve the above problems, which involves injecting grout into the space below the base plate of the column base located above the foundation, and filling the space between the anchor bolts protruding from the foundation and the oversized holes for the anchor bolts formed in the base plate with the grout. The process involves fitting a washer onto the anchor bolt protruding from the anchor bolt hole on the base plate and screwing a nut onto it, A step of creating a frame for filling the grout, positioned close to the outer edge of the base plate, The process involves filling the grout from the grout filling section provided in the filling frame, and allowing the filled grout to overflow from a notch in at least one of the washers that is connected to the bolt insertion hole of the washer and has an open edge. For areas where the above-mentioned filled grout did not overflow, the grout injection nozzle is inserted into the notch of the washer at that location, and the grout is injected. This method is characterized by including (hereinafter referred to as the first method in this section).

[0012] In the first method described above, a grout filling frame is created close to the outer edge of the base plate, and the grout is filled from the grout filling section provided in this filling frame. This eliminates the need to apply pressure to the grout in the gap between the base plate and the filling frame, which is a problem when pouring grout through the gap between the base plate and the filling frame, and also suppresses the prolonged injection time that would occur if all the grout were injected from the groove of the washer. Furthermore, since the filled grout overflows from at least one notch in the washer, the number of insufficiently filled areas in the grout filling section can be minimized. For any insufficiently filled areas where the filled grout did not overflow, a grout injection nozzle is inserted into the notch in the washer at that location, and grout is injected, so that ultimately all the gaps between the anchor bolts and the anchor bolt holes can be filled with grout. Furthermore, since the notch in the washer connects to the bolt insertion hole of the washer and the edge of the washer is open, air can be effectively removed during grout filling from the grout-filled section, and additional grout can be effectively injected by inserting a grout injection nozzle into the notch.

[0013] Furthermore, the method for fixing the base of a building column according to this invention involves injecting grout into the space below the base plate at the base of the column located above the foundation, and filling the space between the anchor bolts protruding from the foundation and the oversized holes for the anchor bolts formed in the base plate with the grout. A washer having a notch connected to the bolt insertion hole and with an open edge, and a hole edge opening cut out in one direction from the bolt insertion hole, is fitted onto the anchor bolt protruding from the anchor bolt hole on the base plate, and a nut is screwed onto the anchor bolt, A step of creating a frame for filling the grout, spaced apart from the outer edge of the base plate, The process of filling the above-mentioned grout into the above-mentioned filling frame, The process involves inserting a grout injection nozzle into the notch of the washer in the area where the filled grout did not overflow, and injecting the grout. This method is characterized by including (hereinafter referred to as the second method in this section).

[0014] In the second method described above, for areas where the filled grout did not overflow from the washer, the grout injection nozzle is inserted into the notch in the washer at that location, and grout is injected, thereby filling all the spaces between the anchor bolts and the holes for the anchor bolts with grout. Furthermore, since the washer has an opening at the edge of the hole, air can be effectively removed when additional grout is injected by inserting the grout injection nozzle into the notch.

[0015] In the first and second methods described above, the outer shape of the washer may be an octagon formed by cutting off the four corners of a square. This reduces the amount of washer material used compared to a circular washer that accommodates the octagon, and also makes it easier to avoid the problem of the corners of the washer contacting the weld bead between the column and the base plate, which can occur when the washer is a square.

[0016] In the first method described above, the washer may have a hole edge opening cut out in one direction from the bolt insertion hole of the washer. This allows for better air removal during grout filling from the grout-filled section due to the presence of the hole edge opening, and also allows for better injection of additional grout by inserting a grout injection nozzle into the notch due to the presence of the hole edge opening.

[0017] The outer shape of the washer is a square or an octagon with four corners of the square cut off. The one direction in which the hole-edge opening is formed is the direction of one of the corners. The hole-edge opening and the notch are positioned 180 degrees to 135 degrees apart from each other around the bolt insertion hole. The width of the hole-edge opening may be substantially the same as the width of the notch. According to this, it becomes easy to secure the hole-edge opening while maintaining the strength of the washer.

[0018] Further, the washer for the column base fixing structure of this invention is a washer that is fitted and used on the base plate in which grout is injected into the lower space of the base plate in the column base positioned above the foundation, and the grout is also filled between the anchor bolt protruding from the foundation and the anchor bolt hole which is an oversized hole formed in the base plate. It is characterized by having a notch that is connected to the bolt insertion hole of the washer and the edge side of the washer is open.

[0019] With the above configuration, since the notch is connected to the bolt insertion hole of the washer and the edge side of the washer is open, air bleeding during grout filling from the grout filling portion can be performed well, and additional injection of grout by inserting a grout injection nozzle into the notch can also be performed well.

[0020] The width of the notch may be 10 mm or more and 18 mm or less. According to this, compared with the case where the width of the notch is less than 10 mm, air bleeding during grout filling from the grout filling portion can be performed better, and additional injection of grout by inserting a grout injection nozzle into the notch can also be performed better. Also, compared with the case where the width of the notch exceeds 18 mm, a decrease in the strength of the washer can be avoided.

[0021] The outer shape of the washer may be an octagon obtained by cutting off four corners of a square. According to this, compared with a circular washer into which the above octagon fits, the amount of washer material used can be reduced, and it becomes easy to avoid the problem that the corners of the washer contact the welding beads of the column and the base plate when the washer is made into the above square.

[0022] The washer may have a hole-edge opening cut out in one direction from the bolt insertion hole of the washer. According to this, air bleeding in grout filling from the grout filling portion can be better performed due to the presence of the above hole-edge opening, and additional injection of grout performed by inserting a grout injection nozzle into the notch can also be better performed due to the presence of the above hole-edge opening.

[0023] The outer shape of the washer is a square or an octagon obtained by cutting off four corners of a square, the above one direction in which the hole-edge opening is formed is the direction of one of the above corners, the hole-edge opening and the notch are spaced 180 degrees to 135 degrees apart from each other around the bolt insertion hole, and the width of the hole-edge opening may be substantially the same as the width of the notch. According to this, it becomes easy to secure the hole-edge opening while maintaining the strength of the washer.

Advantages of the Invention

[0024] According to the present invention, in a method of filling grout injected into the space below the base plate between the anchor bolt and the hole for the anchor bolt, various effects such as quickly injecting grout into the space below the base plate and also quickly performing additional injection of grout into insufficiently filled portions of the grout between the anchor bolt and the hole for the anchor bolt can be achieved.

Brief Description of the Drawings

[0025] [Figure 1] It is a perspective explanatory view of a column base fixing structure according to a method for fixing a column base of a building in an embodiment. [Figure 2] It is a sectional explanatory view of a column base fixing structure according to a method for fixing a column base of a building in an embodiment. [Figure 3] This is a plan view diagram illustrating the washer for the column base fixing structure of the embodiment. [Figure 4] This is an explanatory diagram of the additional grout injection in the method for fixing the column base of a building according to the embodiment. [Figure 5] This is a plan view comparison diagram of circular and octagonal washers for a column base fixing structure in an embodiment. [Figure 6] This is an explanatory diagram showing an example of the arrangement of washers for a square-type column base fixing structure of an embodiment, and their contact with the weld bead. [Figure 7] This is an explanatory diagram showing a modified example of a washer for an octagonal type column base fixing structure according to the embodiment. [Figure 8] This is a perspective view diagram illustrating a column base fixing structure related to a column base fixing method for another building embodiment. [Modes for carrying out the invention]

[0026] Embodiments of this invention will now be described based on the attached drawings. As shown in Figures 1 and 2, the method for fixing the column base of a building according to this embodiment involves injecting grout G into the space below the base plate 21 at the column base 2 located above the foundation 1 of the building, and filling the space (clearance) between the multiple anchor bolts 11 protruding from the foundation 1 and the anchor bolt holes 21a, which are oversized holes formed on the edge of the base plate 21 through which these anchor bolts 11 are inserted, with grout G. The diameter of the anchor bolt holes 21a is, for example, 37 mm, which is 10 mm larger, if the anchor bolts 11 are M27 bolts. Level mortar 12 is formed on the center side of the above-mentioned space below, and the base plate 21 is placed on this level mortar 12 after adjusting its height.

[0027] In this method, a washer 3 for the column base fixing structure according to the embodiment is fitted onto the anchor bolt 11 protruding from the anchor bolt hole 21a on the upper surface of the base plate 21. In this example, a circular general washer 4 is placed on top of the washer 3, and nuts 5, 5 are screwed onto the general washer 4. The washer 3 has a notch 3b that connects to the bolt insertion hole 3a for bolt insertion and is open on the edge of the washer 3. The outer diameter of the general washer 4 is about 2 to 3 mm larger than the diameter of the bolt insertion hole 3a, and the diameter of the through hole of the general washer 4 is about 2 to 3 mm larger than the diameter of the anchor bolt 11.

[0028] As an example, as shown in Figure 3, the diameter of the bolt insertion hole 3a in the washer 3 is 30 mm, and the width of the notch 3b is 16 mm. The outer shape of the washer 3 is an octagon formed by cutting off 15 mm from both ends (corners) of a square with a length and width of 75 mm each. In this dimensional setting, the width of the notch 3b is not limited to 16 mm, but can be in the range of 12 mm to 18 mm. The thickness of the washer 3 is, for example, 9 mm.

[0029] In this method, a grout G filling frame 6 is made using a plate or the like, positioned close to the outer edge of the base plate 21. A grout filling section 61 with an opening on the upper side is provided on the side of this filling frame 6.

[0030] Then, grout G is filled into the grout-filled section 61 through the filling port 61a (by pouring it in using a bucket or the like). In the areas of the washer 3 where the grout G overflows from the notch 3b, the grout G is filled into the space (clearance) between the anchor bolt 11 and the anchor bolt hole 21a. In this grout filling process, it is sufficient if the filled grout G overflows from the notches 3b of all the washers 3 within a certain amount of time. However, if the filled grout G does not overflow from the notches 3b of all the washers 3 after a certain amount of time has passed, it is sufficient if the filled grout G overflows from at least one notch 3b of the washer 3 within a certain amount of time, rather than waiting further for the filled grout G to overflow from all the notches 3b of all the washers 3.

[0031] Next, for any areas where the filled grout G did not overflow due to insufficient filling, as shown in Figure 4, the grout injection nozzle 7 is inserted into the notch 3b of the washer 3 at that location, and additional grout G is injected between the anchor bolt 11 and the anchor bolt hole 21a (clearance).

[0032] With the above method, a filling frame 6 is created close to the outer edge of the base plate 21, and grout G is filled from the grout filling section 61 provided in this filling frame 6. This eliminates the need to apply pressure to the grout G in the gap between the base plate 21 and the filling frame 6, which is a problem when pouring grout G through the gap. It also suppresses the long injection time that occurs when injecting all of the grout G from the groove of the washer in the conventional method. Furthermore, since the filled grout G overflows from the notch 3b of at least one washer 3, the number of insufficiently filled areas in the grout filling section 61 can be minimized. For any insufficiently filled areas where the filled grout G did not overflow, a grout injection nozzle 7 is inserted into the notch 3b of the washer 3 at that location, and grout G is injected, so that ultimately all grout G can be filled between the anchor bolts 11 and the anchor bolt holes 21a. Furthermore, since the notch 3b of the washer 3 is connected to the bolt insertion hole 3a of the washer 3 and the edge of the washer 3 is open, air can be effectively removed during grout filling from the grout filling section 61, and additional grout G can be effectively injected by inserting the grout injection nozzle 7 into the notch 3b.

[0033] When the width of the notch 3b in the washer 3 is 10 mm or more and 18 mm or less, compared to when the width of the notch 3b is less than 10 mm, air can be better removed during grout filling from the grout filling section 61, and additional grout G can be injected more effectively by inserting the grout injection nozzle 7 into the notch 3b. Furthermore, compared to when the width of the notch 3b exceeds 18 mm, a reduction in the strength of the washer 3 can be avoided.

[0034] If the outer shape of the washer 3 is an octagon formed by cutting off the four corners of a square, as shown in Figure 5, the amount of washer material used can be reduced compared to a circular washer 3X, indicated by the dashed line that encloses the octagon. However, if a circular washer is used that fits inside the octagon, the washer strength may be insufficient compared to the octagonal washer 3. Also, as shown in Figure 6, if the washer 3 is a square washer 3Y, its corners may come into contact with the weld bead 211 of the column and the base plate 21. In other words, if the column base 2 is a corner column or a side column, and a parapet wall 13 is constructed near the base plate 21 prior to the erection of the column, when filling grout G through the notch 3b of the washer 3Y, the position of the notch 3b must be oriented in a direction that allows for grout filling at locations A, B, and C shown in the figure. In particular, for locations B and C, using a square washer 3Y with corners increases the likelihood of contact with the weld bead 211 of the column base 2, limiting the range of adjustment for the position of the notch 3b. Using an octagonal washer 3 makes it easier to avoid the problem of contact with the weld bead 211.

[0035] Next, Figure 7 shows an octagonal washer 3A, which is a modified example of the octagonal washer 3. This washer 3A has a hole edge opening 3c that is cut out in one direction from the bolt insertion hole 3a of the washer 3A toward one corner of the square (the corner cut-off side of the octagon). The hole edge opening 3c is located 180 degrees away from the bolt insertion hole 3a with respect to the notch 3b, and is approximately the same width as the notch 3b. Furthermore, in the hole edge opening 3c, the distance from the center of the bolt insertion hole 3a to the edge of the hole edge opening 3c is approximately equal to, for example, the diameter of the bolt insertion hole 3a, which is 30 mm, and the size of the cutout of the hole edge opening 3c is secured. This size of cutout is such that even if a general washer 4 is placed there, the hole edge opening 3c is not blocked by the general washer 4 and a certain opening range is formed.

[0036] According to this, air can be better removed during grout filling from the grout-filled section 61 due to the presence of the hole edge opening 3c, and additional grout G can also be better injected by inserting the grout injection nozzle 7 into the notch 3b due to the presence of the hole edge opening 3c. Furthermore, since the hole edge opening 3c is cut out in one direction on the side of one corner of the square of the washer 3A (the side where the corner of the octagon is cut off), the amount of material between the edge of the hole edge opening 3c and the edge of the washer 3A on the corner side can be increased compared to a shape in which the cutout is on the side of one side of the square of the washer 3A, thus avoiding a reduction in the strength of the washer 3A.

[0037] Thus, in washer 3A, the hole edge opening 3c is positioned 180 degrees away from the notch 3b with respect to the bolt insertion hole 3a, and is approximately the same width as the notch 3b. This makes it easy to secure the hole edge opening 3c while maintaining the strength of washer 3A. Note that the above separation angle is not limited to 180 degrees; the hole edge opening 3c and the notch 3b may be positioned at a separation of 180 to 135 degrees from each other with respect to the bolt insertion hole 3a. Furthermore, the hole edge opening 3c may also be formed in washer 3X and washer 3Y.

[0038] Figure 8 shows a method for fixing the column base of another building. Note that components identical to those in the method shown in Figure 1 are denoted by the same reference numerals, and their explanations are omitted. In this method as well, grout G is injected into the space below the base plate 21 at the column base 2 located above the building's foundation 1. Grout G is also filled into the space (clearance) between the multiple anchor bolts 11 protruding from the foundation 1 and the oversized holes 21a formed on the edge of the base plate 21 through which these anchor bolts 11 are inserted. The diameter of the anchor bolt holes 21a is, for example, 37mm, which is 10mm larger, if the anchor bolts 11 are M27 bolts.

[0039] On the other hand, in this method, a washer 3A (not limited to octagonal, but can also be square, circular, etc.) shown in Figure 7 is fitted onto the anchor bolt 11 protruding from the anchor bolt hole 21a on the upper surface of the base plate 21. In addition, a grout filling frame 6 is made so that there is a gap of about 40 mm from the outer edge of the base plate 21. The grout G can be poured through the above gap. A section for additional grout filling will be formed in the above gap.

[0040] When the grout G is poured in, in the areas of the washer 3A where the grout G overflows from the notch 3b, the grout G fills the space (clearance) between the anchor bolt 11 and the anchor bolt hole 21a. After a certain amount of time has passed during this grout filling process, the pouring of grout G is terminated even if there is no more overflow of grout G from the notch 3b in the washer 3A.

[0041] Then, for areas where the filled grout G did not overflow due to insufficient filling, the grout injection nozzle 7 is inserted into the notch 3b of the washer 3A at that location, as shown in Figure 4, and additional grout G is injected between the anchor bolt 11 and the anchor bolt hole 21a (clearance). This method can also be described as a method of forming a post-filled grout area in which the washer 3A is used exclusively for the additional injection of grout G.

[0042] With the above method, for areas where the filled grout G did not overflow due to insufficient filling, the grout injection nozzle 7 is inserted into the notch 3b of the washer 3A at that location, and additional grout G is injected, so that all the space between the anchor bolts 11 and the anchor bolt holes 21a can be filled with grout G. In addition, the washer 3A has an opening 3c at the edge of the hole, and this opening 3c allows for good air removal when additional grout G is injected.

[0043] Although embodiments of this invention have been described above with reference to the drawings, this invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as this invention, or within the equivalent scope. [Explanation of Symbols]

[0044] 1: Basics 2: Column base 3: Washers for fixing column bases 3A: Washer for fixing column base structure 3X: Washer for fixing column base structure 3Y: Washer for fixing column base structure 3a: Bolt insertion hole 3b: Notch 3c: Hole edge opening 4: General Washer 5: Nut 6: Filling frame 7: Grout injection nozzle 11: Anchor bolts 12: Leveling mortar 21: Base plate 21a: Hole for anchor bolt 61: Grout filling section 61a: Filling port 211: Weld bead G: Grout

Claims

1. A method for fixing the base of a building column, comprising injecting grout into the space below the base plate at the base of the column located above the foundation, and filling the space between the anchor bolts protruding from the foundation and the oversized holes for the anchor bolts formed in the base plate, wherein The process involves fitting a washer onto the anchor bolt protruding from the anchor bolt hole on the base plate and screwing a nut onto it, A step of creating a frame for filling the grout, positioned close to the outer edge of the base plate, The process involves filling the grout from the grout filling section provided in the filling frame, and allowing the filled grout to overflow from a notch in at least one of the washers that is connected to the bolt insertion hole of the washer and has an open edge. For areas where the above-mentioned filled grout did not overflow, the grout injection nozzle is inserted into the notch of the washer at that location, and the grout is injected. A method for fixing the base of a building column, characterized by including the following:

2. A method for fixing the base of a building column, comprising injecting grout into the space below the base plate at the base of the column located above the foundation, and filling the space between the anchor bolts protruding from the foundation and the oversized holes for the anchor bolts formed in the base plate, wherein A washer having a notch connected to the bolt insertion hole and with an open edge, and a hole edge opening cut out in one direction from the bolt insertion hole, is fitted onto the anchor bolt protruding from the anchor bolt hole on the base plate, and a nut is screwed onto the anchor bolt, A step of creating a frame for filling the grout, spaced apart from the outer edge of the base plate, The process of filling the above-mentioned grout into the above-mentioned filling frame, The process involves inserting a grout injection nozzle into the notch of the washer in the area where the filled grout did not overflow, and injecting the grout. A method for fixing the base of a building column, characterized by including the following:

3. A method for fixing the base of a building column according to claim 1 or claim 2, characterized in that the outer shape of the washer is an octagon obtained by cutting off the four corners of a square.

4. A method for fixing the base of a building column according to claim 1, characterized in that the washer has a hole edge opening cut out in one direction from the bolt insertion hole of the washer.

5. A method for fixing the base of a building column according to claim 2 or claim 4, characterized in that the outer shape of the washer is a square or an octagon with four corners cut off from a square, the direction in which the hole edge opening is formed is the direction of one of the corners, the hole edge opening and the notch are spaced 180 to 135 degrees apart from each other with respect to the bolt insertion hole, and the width of the hole edge opening is approximately the same width as the width of the notch.

6. In a column base fixing structure in which grout is injected into the space below the base plate at the column base located above the foundation, and the grout is also filled between the anchor bolts protruding from the foundation and the anchor bolt holes which are oversized holes formed in the base plate, a washer is fitted onto the anchor bolts protruding from the anchor bolt holes on the base plate for use, A washer for a column base fixing structure, characterized in that it has a notch that connects to a bolt insertion hole in the washer and the edge of the washer is open.

7. A washer for a column base fixing structure according to claim 6, characterized in that the outer shape of the washer is an octagon formed by cutting off the four corners of a square.

8. A washer for a column base fixing structure according to claim 6, characterized in that it has a hole edge opening cut out in one direction from the bolt insertion hole of the washer.

9. A washer for a column base fixing structure according to claim 8, wherein the outer shape of the washer is a square or an octagon with four corners cut off from a square, the direction in which the hole edge opening is formed is the direction of one of the corners, the hole edge opening and the notch are spaced 180 to 135 degrees apart from each other with respect to the bolt insertion hole, and the width of the hole edge opening is approximately the same as the width of the notch.

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