JP2019035271A - Anchor reinforcement structure, anchor reinforcement method, and anchor reinforcement member - Google Patents

Abstract

To provide an anchor reinforcement structure capable of efficiently reinforcing an anchor bolt, an anchor reinforcement method, and an anchor reinforcement member.SOLUTION: A reinforcement member 11 is constituted of a shaft member 13 and a fixing member 15. The shaft member 13 has an expanded portion formed at one end and a male screw part formed on the other end portion thereof. There exists a shank portion between the expanded portion and the male screw part. A diameter of the shank portion is smaller than a diameter of a trough of the male screw part. The fixing member 15 is capable of receiving the shaft member 13 therein. The fixing member 15 has a hole 25 formed at one end thereof, through which the male screw part and the shank can be inserted. The expanded portion is joined to a thread portion 9a of an anchor bolt 9. In this state, the fixing member 15 is disposed to cover the shaft member 13 with the male screw part protruding upward from the hole 25 of the fixing member 15. A nut 17 is provided to the male screw part and is fixed to an upper portion of the fixing member 15.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an anchor reinforcement structure, an anchor reinforcement method, and an anchor reinforcement member for an anchor bolt that fixes, for example, a base plate of a column base.

  In order to prevent the collapse of the structure due to an earthquake, a structure such as a pillar is required to have a seismic strength of a predetermined level or more. However, since structures that were constructed before the current seismic standards were not required to be as severe as current seismic strength, the old structures may not meet the current seismic standards. However, it takes time and cost to newly rebuild all structures such as pillars.

  As a method for reinforcing such a structure, for example, there is a method of constructing a reinforced concrete root winding portion by placing concrete around a column base portion of an existing column. However, since concrete is constructed around the columns, a lot of work is required such as rebar and formwork, and the dimensions of the columns are increased by the amount of concrete, which hinders the convenience of the building.

  On the other hand, structures such as column bases are usually fixed to the foundation or ground by anchor bolts (for example, Patent Document 1).

JP 2006-104780 A

  If the strength and deformation capacity of the anchor bolt are not sufficient, there is a risk that the structure will fall due to the anchor bolt breaking or the like at an early stage. For this reason, reinforcement of an anchor bolt may be required for reinforcement of a structure. In particular, anchor bolts used in old steel-framed exposed column bases often have threaded parts that break before the shaft part of the anchor bolt is sufficiently plastically deformed. Many are scarce.

  The present invention has been made in view of such problems, and an object thereof is to provide an anchor reinforcement structure, an anchor reinforcement method, and an anchor reinforcement member that can efficiently reinforce an anchor bolt.

  In order to achieve the above-described object, a first invention is an anchor reinforcing structure, comprising an anchor bolt and a reinforcing member joined to an upper portion of the anchor bolt, and the reinforcing member is a shaft member. And a fixing member capable of accommodating the shaft member therein, with a gap between the shaft member and a fixing surface of the fixing member, and one end of the shaft member being the anchor bolt The fixing member has a hole at one end thereof through which the shaft member can be inserted, and the shaft protrudes above the fixing member in a state where the fixing member is covered on the shaft member. An anchor reinforcing structure, wherein a member is fixed at an upper portion of the fixing member, and the shaft member starts plastic deformation with a load smaller than a load at which a joint portion between the shaft member and the anchor bolt breaks. It is.

  The anchor bolt may fix the base plate of the column base.

  The lower end portion of the shaft member is formed with an enlarged diameter portion thicker than the thickness of the shaft portion of the intermediate portion of the shaft member, and a groove is formed on the lower surface side of the enlarged diameter portion. An anchor bolt may be welded at the groove.

  The load at which the shaft member starts plastic deformation may be larger than the load at which the threaded portion of the anchor bolt starts plastic deformation and smaller than the load at which the threaded portion of the anchor bolt breaks.

  The load at which the shaft member starts plastic deformation may be smaller than the load at which the threaded portion of the anchor bolt starts plastic deformation.

  According to the first invention, the reinforcing member is attached to the upper part of the anchor bolt, and the shaft member starts plastic deformation with a load smaller than the load at which the joint portion with the anchor bolt breaks. A sufficient amount of deformation can be ensured before the joint with the anchor bolt breaks.

  Such a reinforcing member is particularly effective for reinforcing the anchor bolt that fixes the base plate of the column base.

  Further, by forming an enlarged diameter portion thicker than the thickness of the shaft portion of the intermediate portion of the shaft member at the lower end portion of the shaft member, and forming a groove on the lower surface side of the enlarged diameter portion, the anchor bolt and the shaft member Can be easily welded. At this time, since the weld area of the joint can be made larger than the cross-sectional area of the intermediate part of the shaft member, the shaft member can be plastically deformed with a load smaller than the load at which the joint with the anchor bolt breaks. it can.

  In addition, if the load at which the shaft member starts plastic deformation is larger than the load at which the threaded portion of the anchor bolt starts plastic deformation and smaller than the load at which the threaded portion breaks, high strength and the effect of preventing anchor breakage can be obtained. It can be compatible.

  Further, if the load at which the shaft member starts plastic deformation is smaller than the load at which the threaded portion of the anchor bolt starts plastic deformation, the strength design of the shaft member is easy.

  The second invention is a method of reinforcing an existing anchor, using an anchor reinforcing member comprising a shaft member and a fixing member capable of accommodating the shaft member therein, and removing a nut of an anchor bolt; Welding one end of the shaft member to the anchor bolt, covering the fixing member over the shaft member, and projecting the other end of the shaft member over the fixing member, A step of fixing the shaft member and the fixing member at an upper portion of the fixing member, and there is a gap between the shaft member and the fixing surface of the fixing member. The anchor reinforcement method is characterized in that plastic deformation is started with a load smaller than a load at which a threaded portion of an anchor bolt breaks.

  According to the second invention, the existing anchor bolt can be easily reinforced.

  3rd invention is a reinforcing member of an anchor, Comprising: A shaft member and the fixing member which can accommodate the said shaft member inside are comprised, The intermediate part of the said shaft member is provided in the lower end part of the said shaft member A diameter-enlarged portion thicker than the diameter of the diameter-enlarged portion, a groove is formed on the lower surface side of the enlarged-diameter portion, and the fixing member has a hole through which the shaft member can be inserted at one end. It is the anchor reinforcement member characterized.

  According to the third invention, a reinforcing member capable of easily reinforcing the anchor bolt can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the anchor reinforcement structure which can reinforce an anchor bolt efficiently, an anchor reinforcement method, and an anchor reinforcement member can be provided.

The side view which shows the anchor reinforcement structure 1. FIG. The expanded sectional view of the anchor reinforcement structure 1. FIG. The exploded view of the reinforcement member 11. FIG. The figure which shows the existing column base 3. FIG. The figure which shows the state which removed the nut 27. FIG. The figure which shows the state which attached the shaft member 13. FIG. The figure which shows the state which arrange | positions the fixing member 15 and attaches the nut 17. FIG. The expanded sectional view of the anchor reinforcement structure 1a. The figure which shows the state which the column base 3 displaced. The expanded sectional view of the F section of FIG. The figure which shows the relationship between a load and a deformation amount.

  Hereinafter, the anchor reinforcement structure 1 concerning embodiment of this invention is demonstrated. FIG. 1 is a side view showing an anchor reinforcement structure 1. In the following description, the anchor reinforcement structure 1 shows a reinforcement structure for the anchor bolt 9 that fixes the base plate 7 of the column base 3. However, the present invention is not limited to this, and any structure that is fixed by an anchor can be used. Applicable.

  The column base 3 is constructed on a floor 5 (for example, a foundation). A base plate 7 is fixed on the floor 5 with anchor bolts 9. A reinforcing member 11 is fixed to the upper part of the anchor bolt 9.

  2 is an enlarged cross-sectional view of a part A in FIG. 1, and FIG. 3 is an exploded cross-sectional view of the reinforcing member 11. The reinforcing member 11 includes a shaft member 13 and a fixing member 15. As shown in FIG. 3, the shaft member 13 is provided with a male screw portion 21 at one end (upper end) and a diameter-enlarged portion 22 at the other end (lower end). An intermediate portion between the enlarged diameter portion 22 and the male screw portion 21 is a shaft portion 23. The enlarged diameter portion 22 is thicker than the thickness of the shaft portion 23. Further, the diameter of the shaft portion 23 is smaller than the diameter of the valley portion of the male screw portion 21 and the diameter of the enlarged diameter portion 22.

  The fixing member 15 can accommodate the shaft member 13 therein. A hole 25 into which the male screw portion 21 and the shaft portion 23 can be inserted is formed at one end portion of the fixing member 15.

  As shown in FIG. 2, the enlarged diameter portion 22 at the end of the shaft member 13 is joined to the threaded portion 9 a of the anchor bolt 9. The shaft member 13 and the anchor bolt 9 are joined by, for example, welding or pin joining. In the illustrated example, the shaft member 13 and the anchor bolt 9 are joined by a welded portion 31. That is, the shaft member 13 and the anchor bolt 9 are joined by means other than the screw structure. In this case, the shaft member 13 and the anchor bolt 9 can be easily welded by providing the groove 29 on the lower surface of the enlarged diameter portion 22. Note that the weld area of the welded portion 31 (the cross-sectional area of the joint surface between the weld bead and the anchor bolt 9, which is a cross section perpendicular to the axial direction of the anchor bolt 9) is larger than the cross-sectional area of the shaft portion 23.

  In this state, the fixing member 15 is disposed so as to cover the shaft member 13, and the male screw portion 21 protrudes upward from the hole 25 of the fixing member 15. Further, the male screw portion 21 is provided with a nut 17 and is fixed to the upper portion of the fixing member 15.

  At this time, a gap is formed between the tip of the shaft member 13 (the enlarged diameter portion 22) and the upper surface of the base plate 7 that is a fixing surface of the fixing member 15. That is, the shaft member 13 does not contact the fixed surface of the fixing member 15.

  The shaft member 13 and the fixing member 15 are made of steel, for example. The shaft member 13 has a male threaded portion 21 formed by tapping at the end of a rod-shaped material, and the shaft portion 23 may be made thinner by, for example, cutting the rod-shaped material.

  Next, the reinforcement method of the existing column base using the reinforcement member 11 is demonstrated. FIG. 4 is a diagram showing the existing column base 3. As described above, the column base 3 is installed on the floor 5. The base plate 7 of the column base 3 is fixed to the floor 5 by anchor bolts 9 and nuts 27.

  From this state, the nut 27 is removed from the anchor bolt 9 as shown in FIG. 5 (arrow C in the figure). Therefore, the threaded portion 9a of the anchor bolt 9 is projected on the base plate 7.

  Next, as shown in FIG. 6, the shaft member 13 is joined to the anchor bolt 9 protruding from the base plate 7. For example, the threaded portion 9 a of the anchor bolt 9 and the enlarged diameter portion 22 of the shaft member 13 are welded by the welded portion 31. At this time, as described above, a gap is formed between the lower end of the shaft member 13 (the enlarged diameter portion 22) and the upper surface of the base plate 7.

  Next, as shown in FIG. 7, the fixing member 15 is put on the shaft member 13. At this time, the male screw portion 21 of the shaft member 13 is inserted into the hole 25 of the fixing member 15 and protrudes above the fixing member 15. Furthermore, the anchor reinforcement structure 1 is constructed by attaching and fixing the nut 17 to the male screw portion 21 from above the fixing member 15 (arrow D in the figure). As the nut 17, the nut 27 that has fixed the anchor bolt 9 may be used as it is.

  When a plurality of anchor bolts 9 are adjacent to each other, after attaching the shaft member 13 to each anchor bolt 9, one fixing member 15 provided with a plurality of holes 25 is connected to the plurality of shaft members 13. The shaft members 13 may be fixed with nuts 17 in a lump.

  Moreover, you may join the shaft member 13 and the fixing member 15 by the welding part 31a like the anchor reinforcement structure 1a shown in FIG. In this case, the male screw portion 21 may not be provided at the upper end portion of the shaft member 13. Thus, the joining method is not particularly limited as long as the shaft member 13 and the fixing member 15 can be joined.

  Next, the function of the anchor reinforcement structure 1 will be described. FIG. 9 is a diagram showing a state in which the column base 3 is tilted (arrow E in the figure) in the event of an earthquake, and FIG. 10 is an enlarged cross-sectional view of a portion F in FIG. When the base plate 7 is lifted by an earthquake, tensile stress is applied to the anchor bolt 9 and the shaft member 13 of the reinforcing member 11.

  At this time, since the cross-sectional area of the shaft portion 23 of the shaft member 13 is smaller than the cross-sectional area of the valley portion of the male screw portion 21 and the cross-sectional area of the joint portion (welded portion 31) between the shaft member 13 and the anchor bolt 9, The shaft portion 23 undergoes plastic deformation (elongation deformation) with a smaller load than the male screw portion 21 or the welded portion 31 starts plastic deformation (arrow H in FIG. 10).

  Furthermore, the shaft portion 23 starts plastic deformation with a load smaller than the load at which the threaded portion 9a of the anchor bolt 9 breaks. FIG. 11 is a diagram illustrating the relationship between the load of each part and the amount of deformation. In the figure, I is a view showing the behavior of the anchor bolt 9 (screw portion 9a). The threaded portion 9a starts plastic deformation with a predetermined load (L in the figure). However, since the anchor bolt has insufficient strength and deformability, the threaded portion breaks before the shaft portion of the anchor bolt is sufficiently plastically deformed (M in the figure).

  On the other hand, the shaft portion 23 of the shaft member 13 behaves like K in the figure, for example. That is, the shaft portion 23 starts plastic deformation with a load smaller than the load at which the threaded portion 9a of the anchor bolt 9 breaks. For this reason, if the shaft part 23 is in a deformation amount range in which plastic deformation is possible, a load necessary for the screw part 9a to break is not applied to the screw part 9a.

  Thus, in this embodiment, it can prevent that the anchor bolt 9 fractures | ruptures because the axial part 23 preferentially plastically deforms. Further, since the load at which the shaft portion 23 starts plastic deformation is only slightly smaller than the load at which the screw portion 9a breaks, it is possible to suppress the shaft portion 23 from being easily plastically deformed with a small load. Can do. Thus, the load at which the shaft portion 23 starts plastic deformation is desirably larger than the load at which the screw portion 9a of the anchor bolt 9 starts plastic deformation and smaller than the load at which the screw portion 9a breaks.

  Here, the inclination allowed for the column base 3 is about 1/30 rad. For this reason, a necessary elongation amount is set in advance from the size of the base plate 7 and the inclination. At this time, by setting the gap between the shaft member 13 and the base plate 7 to be equal to or greater than a necessary elongation amount, the shaft portion 23 can be reliably allowed to extend.

  Note that the shaft portion 23 of the shaft member 13 may behave as shown in FIG. That is, the shaft portion 23 may start plastic deformation with a load smaller than the load at which the threaded portion 9a of the anchor bolt 9 starts plastic deformation. Even if it does in this way, the load required for the thread part 9a to fracture | rupture is not provided to the thread part 9a in the deformation amount range in which the shaft part 23 can be plastically deformed. Further, it is easy to design the strength of the shaft portion 23 for starting the plastic deformation with a load smaller than the load at which the threaded portion 9a of the anchor bolt 9 starts the plastic deformation.

  In this case, as compared with the above-described example, the shaft portion 23 starts plastic deformation with a smaller load. However, since the plastic deformation of the screw portion 9a of the anchor bolt 9 can be prevented, the earthquake Later, the repair can be completed simply by replacing the shaft member 13.

  As described above, according to the present embodiment, the anchor reinforcement structure 1 can be obtained with a simple operation. Therefore, reinforcement of the existing column base 3 is easy. Moreover, since the anchor reinforcement structure 1 can prevent the anchor bolt 9 that fixes the column base 3 from being broken, the column base 3 can be prevented from falling.

  Moreover, after an earthquake, it can repair easily by replacing | exchanging the shaft member 13. FIG.

  Further, since the cross-sectional area of the shaft portion 23 of the shaft member 13 is smaller than the cross-sectional area of the valley portion of the male screw portion 21 and the cross-sectional area of the welded portion 31, the shaft portion 23 of the shaft member 13 is preferentially plastically deformed. Can do.

  Further, if the plastic deformation start load of the shaft portion 23 is larger than the load at which the threaded portion 9a of the anchor bolt 9 starts plastic deformation and smaller than the load at which the threaded portion 9a breaks, the anchor bolt 9 can be prevented from breaking. , High strength can be achieved at the same time.

  Further, if the plastic deformation start load of the shaft portion 23 is smaller than the load at which the screw portion 9a of the anchor bolt 9 starts plastic deformation, the screw portion 9a of the anchor bolt 9 can be prevented from being deformed after the earthquake. .

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

DESCRIPTION OF SYMBOLS 1, 1a ......... Anchor reinforcement structure 3 ......... Column base 5 ......... Floor 7 ......... Base plate 9 ......... Anchor bolt 9a ......... Screw part 11 ......... Reinforcement member 13 ......... Shaft member 15 ......... Fixing member 17 ......... Nut 21 ......... Male threaded part 22 ......... Diameter-enlarged part 23 ......... Shaft part 25 ......... Hole 27 ......... Nut 29 ......... Bevels 31, 31a …… …welded part

Claims (7)

An anchor reinforcement structure,
Anchor bolts,
A reinforcing member joined to the top of the anchor bolt;
Comprising
The reinforcing member includes a shaft member, and a fixing member capable of accommodating the shaft member therein,
A gap is formed between the shaft member and the fixing surface of the fixing member, and one end of the shaft member is joined to the anchor bolt,
The fixing member has a hole through which the shaft member can be inserted at one end,
In a state where the fixing member is put on the shaft member, the shaft member protruding to the upper part of the fixing member is fixed at the upper part of the fixing member,
The anchor reinforcement structure according to claim 1, wherein the shaft member starts plastic deformation with a load smaller than a load at which a joint portion between the shaft member and the anchor bolt breaks.   2. The anchor reinforcing structure according to claim 1, wherein the anchor bolt fixes a base plate of a column base.   The lower end portion of the shaft member is formed with an enlarged diameter portion thicker than the thickness of the shaft portion of the intermediate portion of the shaft member, and a groove is formed on the lower surface side of the enlarged diameter portion. The anchor reinforcement structure according to claim 1 or 2, wherein an anchor bolt is welded at the groove.   The load at which the shaft member starts plastic deformation is larger than the load at which the threaded portion of the anchor bolt starts plastic deformation, and smaller than the load at which the threaded portion of the anchor bolt breaks. The anchor reinforcement structure according to claim 3.   The anchor reinforcing structure according to any one of claims 1 to 3, wherein a load at which the shaft member starts plastic deformation is smaller than a load at which a thread portion of the anchor bolt starts plastic deformation. A method for reinforcing an existing anchor,
Using an anchor reinforcing member comprising a shaft member and a fixing member capable of accommodating the shaft member inside,
Removing the nut of the anchor bolt;
Welding one end of the shaft member to the anchor bolt;
Covering the fixing member with the shaft member, causing the other end of the shaft member to protrude above the fixing member, and fixing the shaft member and the fixing member at an upper portion of the fixing member;
Comprising
There is a gap between the shaft member and the fixing surface of the fixing member, and the shaft member starts plastic deformation with a load smaller than a load at which the threaded portion of the anchor bolt breaks. Anchor reinforcement method to do. An anchor reinforcement member,
A shaft member;
A fixing member capable of accommodating the shaft member therein;
Comprising
The lower end portion of the shaft member is formed with an enlarged diameter portion thicker than the thickness of the intermediate portion of the shaft member, and a groove is formed on the lower surface side of the enlarged diameter portion,
The anchor member has a hole through which the shaft member can be inserted at one end.

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