JP7747253B2 - Wooden shaft members and building frames - Google Patents

Description

The present invention relates to wooden shaft members and building frames.

In wooden buildings constructed using the wooden frame construction method, the wooden shaft members that make up the columns, beams, and foundations are joined together using fastening hardware such as drift pins and lag screw bolts. Fastening the members together increases the rigidity and strength of the joints, improving seismic performance. However, while the use of fastening hardware such as lag screw bolts increases the rigidity of the joints, it also reduces the deformation capacity of the joints, raising concerns about brittle fracture at the joints.

In order to impart deformation performance to the joints between components, various methods have been proposed, including creating an axially extending long hole inside a fastening fixture such as a screw or bolt, and fastening the bolt to a thread groove at the end of the long hole, or crimping the bolt to a pipe with threads on its outer surface, thereby increasing the bolt's deformation performance when pulled.

For example, Patent Document 1 proposes a connecting fitting comprising a lag screw body and a connecting threaded shaft that is integral with the lag screw body and protrudes concentrically from one end of the lag screw body. This lag screw body is constructed from a pipe material with a rotational angular shaft portion on the outer periphery of one end and a bolt crimp-fixing region on the other end, with a helical ridge formed on the outer periphery between the rotational angular shaft portion and the bolt crimp-fixing region. The connecting threaded shaft is formed by the rear end threaded shaft portion of a bolt inserted into the lag screw body, and the other end of the bolt is provided with a tip threaded shaft portion located inside the bolt crimp-fixing region of the lag screw body, with the inner periphery of the bolt crimp-fixing region being crimped onto the tip threaded shaft portion of the bolt, thereby integrating the two. This connecting fitting is said to enable easy and inexpensive manufacture of long lag screw-type connecting fittings and to provide a lag screw-type connecting fitting with high seismic isolation effects that utilizes the elongation performance of the bolt.

Meanwhile, Patent Document 2 proposes a fastener with a cylindrical outer shape and spiral ridges formed on the circumferential surface, an axially extending lead-in hole formed in the center of one end face, and a female thread at the back of the lead-in hole that extends axially and reaches the opposite face, with the diameter of the lead-in hole being larger than the outer diameter of the female thread. By embedding this fastener in, for example, a beam and connecting a lag screw bolt embedded in a column to the fastener via the lead-in hole, when an external force during an earthquake acts and deforms the column and beam so that they separate, the lag screw bolt will plastically deform, absorbing energy and preventing the fastener or lag screw bolt from falling out, thereby avoiding damage to the fastening portion.

Japanese Patent Application Laid-Open No. 2019-2200 JP 2010-7428 A

The connecting fittings and fastening hardware described in Patent Documents 1 and 2 are all expected to rely only on the deformation performance of the tensile side of the bolts they connect. Therefore, while the bolts' deformation performance on the tensile side is exerted in response to the tensile force acting on the joint between the members during an earthquake, sufficient performance cannot be expected to withstand the compressive force acting on the joint during an earthquake. As a result, they cannot be said to have high strain energy absorption performance during an earthquake.

Furthermore, when a building frame is deformed during an earthquake, once the compressive load acting on the connecting fittings and fastening hardware at the joints of the wooden shaft members reaches a certain load, the wooden shaft members may crack due to the pressing force acting from the connecting fittings on the wooden shaft members, but Patent Documents 1 and 2 do not disclose any means for preventing this cracking.

The present invention was made in consideration of the above-mentioned problems, and aims to provide a wooden shaft member that has excellent strain energy absorption performance and can suppress cracking that can occur when a building frame is deformed by utilizing the deformation performance of both the tensile and compressive sides of the metal shaft member attached to the end of the wooden shaft member, and a building frame that is equipped with this wooden shaft member and has excellent earthquake resistance performance.

In order to achieve the above object, one aspect of the wooden shaft member according to the present invention is:
a wooden body having a receiving hole at an end thereof;
a metal fitting embedded in the receiving hole,
The connecting fitting is
a first pipe made of steel, the first pipe having a first hollow portion therein and a first thread groove at one end of the first hollow portion;
a steel shaft member including a steel core material and a first screw and a second screw located at both ends of the core material and having a diameter larger than that of the core material;
a first steel cotter having a second hollow portion therein and a second thread groove;
a part of the first pipe is accommodated in the second hollow portion, the shaft member is accommodated in the second hollow portion and the first hollow portion, the first screw groove and the first screw are screw-fixed, and the second screw groove and the second screw are screw-fixed,
A second steel pipe is provided around the first pipe and axially inside the wooden body relative to the first cotter.

In this aspect, a core material and a shaft member having a first screw and a second screw at both ends, each with a larger diameter than the core material, are disposed in the first hollow portion of the first pipe, which is housed and fixed in the housing hole at the end of the wooden body, and the second hollow portion of the first cotter, which houses a portion of the first pipe. The shaft member is screwed into the first screw groove of the first pipe and the second screw groove of the first cotter. When a tensile force is applied during an earthquake, the first pipe and the shaft member undergo tensile deformation, and when a compressive force is applied, the core material that constitutes the shaft member undergoes buckling deformation, thereby effectively absorbing strain energy during an earthquake.

Furthermore, according to this embodiment, a second steel pipe is provided around the first pipe, axially inward of the first cotter. This allows the second pipe to press down on the first pipe, preventing splitting of the wood body, which can occur starting from the first cotter like a firewood split, and preventing the wood body from opening due to this splitting.

In this embodiment, the steel core material that actually deforms has a smaller diameter than the first and second screws that screw into the first pipe and first cotter. This creates gaps that allow for buckling deformation between the core material and the first hollow portion of the first pipe, and between the core material and the second hollow portion of the first cotter. In the shaft member, the first and second screws at both ends that screw into the first pipe and first cotter are relatively larger in diameter than the central core material. This means that when a compressive force is applied to the shaft member, the core material buckles and deforms, preventing the first and second screws from breaking first.

Furthermore, when the core material buckles, because the first pipe and first cotter are located around the core material and the wooden body is located around the first pipe and first cotter, the core material, which is allowed to deform, buckles inside the first pipe and first cotter, but is restrained by the first pipe, first cotter, and wooden body, preventing buckling failure of the core material. In other words, the first pipe and first cotter are embedded at the ends of the wooden body, and both ends of the shaft member are fixed inside the first pipe and first cotter with a gap between the core material and the first pipe and first cotter, forming so-called buckling-restrained braces at the ends of the wooden shaft member.

The wooden body may be solid wood, or may be made of laminated wood consisting of multiple laminated lamina. For example, even when a weak wood species such as cedar is used, the embedded structure of the first pipe, first cotter, and shaft member allows for stable deformation performance in both compression and tension.

In another aspect of the wooden shaft member according to the present invention,
A second pipe is provided at the end of the first cotter through a gap for allowing deformation of the wooden body.
The second hollow portion of the first cotter is characterized in that a gap for allowing deformation of the core material is provided.

In this aspect, the second pipe is provided at the end of the first cotter via a gap for the deformation of the wooden body. This prevents the first cotter and the second pipe from coming into contact and interfering with each other when a compressive force acts on the wooden body and the core material buckles. Furthermore, the provision of a gap for the deformation of the core material in the second hollow portion of the first cotter allows buckling deformation to occur in the core material when a compressive force acts on the wooden body.

In another aspect of the wooden shaft member according to the present invention,
a second cotter having a third steel pipe, at least a portion of which is buried in the end of the wooden body, and the first pipe is disposed inside the third pipe;
A gap is provided at the end of the third pipe to allow for deformation of the wooden body,
The core material protrudes outward from the end of the wooden body and is further fixed to the second cotter with a screw.

In this aspect, at least a portion of the third pipe provided in the second cotter is embedded in the end of the wooden body, and the core material extends outward from the end of the wooden body and is screwed to the second cotter. This allows the third pipe to exert buckling stiffening power together with the wooden body when the core material buckles. Furthermore, because the third pipe presses against the periphery of the first pipe, it is possible to suppress cracking that may occur in the wooden body starting from the second cotter. Furthermore, by providing both buckling stiffening power and the ability to prevent cracking of the wooden body, it is possible to reduce manufacturing costs.

In another aspect of the wooden shaft member according to the present invention,
The receiving hole is a threaded hole, and the first pipe has a threaded circumferential surface.
The first pipe is threadedly engaged with the receiving hole.

In this embodiment, a first pipe with threads on its circumferential surface is threaded into the receiving hole, which is a screw hole, thereby producing a wooden shaft member with a high joint strength between the receiving hole in the wooden main body and the first pipe. Here, an example of a first pipe with threads on its circumferential surface is a pipe plug screw bolt (pipe LSB).

In another aspect of the wooden shaft member according to the present invention,
The housing hole and the first pipe are fixed to each other via an adhesive.

According to this aspect, for example, a cylindrical receiving hole is bored into the end of the wooden main body, and the cylindrical first pipe is inserted into the receiving hole while filling it with adhesive. This makes it possible to produce a wooden shaft member with high manufacturing efficiency and a strong bond between the receiving hole in the wooden main body and the first pipe.

Another aspect of the wooden shaft member according to the present invention is:
A rotating piece that is rotatably attached to a connecting jig connected to the building frame is directly or indirectly attached to the outer end of the first cotter or the second cotter.

In this aspect, a rotating piece is attached to the outer end of the first or second cotter, which is rotatably attached to a connecting jig connected to the building frame. This allows the wooden shaft member to be attached to columns or beams efficiently and with high strength at a highly flexible attachment angle.

Furthermore, one aspect of the building frame according to the present invention is
The structure includes a wooden brace made of the wooden shaft member, a beam, and a column,
The wooden braces are connected to the beams and the columns.

In this aspect, by using the wooden shaft member of the present invention as a wooden brace, a building frame is formed that has excellent deformation performance on both the compression and tension sides at the joints between the columns or beams and the wooden brace, and has excellent strain energy absorption performance during an earthquake. Furthermore, the deformation performance of the wooden brace suppresses a sudden increase in load at the joints between the columns or beams and the wooden brace when external forces are applied during an earthquake. Furthermore, because the metal fittings such as the first pipe, first cotter, second cotter, and shaft member are embedded inside the wooden body, the metal fittings cannot be seen in their entirety from the outside, resulting in a building frame with wooden braces that has excellent exterior design.

Here, the building frame of this embodiment may be a building frame that constitutes a wooden building in which both the columns and beams are made of wood, a building frame that constitutes a steel-framed building in which the columns and beams are made of steel, or a building frame that constitutes an RC (Reinforced Concrete) building in which the columns and beams are made of reinforced concrete.

As can be seen from the above explanation, the wooden shaft member and building frame of the present invention enable the metal shaft members attached to the ends of the wooden shaft member to exhibit deformation performance on both the tensile and compressive sides, resulting in a wooden shaft member with excellent strain energy absorption performance and the ability to suppress cracking that can occur when the building frame is deformed, as well as a building frame equipped with this wooden shaft member that has excellent earthquake resistance.

1 is a longitudinal cross-sectional view of an example of a wooden shaft member according to a first embodiment. FIG. 10A and 10B are diagrams showing a state in which a compressive force is applied to the wooden shaft member according to the first embodiment. 10A and 10B are diagrams showing a state in which a tensile force is applied to the wooden shaft member according to the first embodiment. FIG. 10 is a longitudinal cross-sectional view of an example of a wooden shaft member according to a second embodiment. 1A to 1E are schematic diagrams showing an example of a building frame according to an embodiment. FIG. 6 is a front view specifically showing the building frame shown in FIG. 5(d).

Below, examples of wooden shaft members and building frames according to each embodiment will be described with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components will be designated by the same reference numerals, and redundant explanations may be omitted.

[Wood shaft member according to the first embodiment]
First, an example of a wooden shaft member according to the first embodiment will be described with reference to Figures 1 to 3. Here, Figure 1 is a longitudinal cross-sectional view of an example of a wooden shaft member according to the first embodiment. Also, Figures 2 and 3 are diagrams showing states in which a compressive force and a tensile force are applied to the wooden shaft member according to the first embodiment, respectively. Here, Figures 1 to 3 show a wooden shaft member 80 cut in half.

The wooden shaft member 80 has a long wooden body 10 with two end portions 11 each having a receiving hole 12, and metal joints 15 embedded in each receiving hole 12.

The wooden body 10 is made of solid wood or laminated wood with laminated lamina. The storage hole 12 provided at the end 11 of the wooden body 10 is, for example, a multi-stage cylindrical storage hole with different cross-sectional dimensions (the illustrated example is a two-stage cylindrical shape).

The connecting fitting 15 includes a first steel pipe 20, a first steel cotter 40, and a steel shaft member 30.

The first pipe 20 has a first hollow portion 21 inside, a first thread groove 22 at one end of the first hollow portion 21, and a threaded circumferential surface 23. This first pipe 20 is a pipe plug screw bolt (pipe LSB) with a threaded circumferential surface.

The receiving hole 12 in the wooden body 10 is, for example, a threaded hole, and the first pipe 20 is screwed into the receiving hole 12 in the wooden body 10 by screwing it into the receiving hole 12. However, the receiving hole may not be a threaded hole, and the circumferential surface of the first pipe may not be threaded, and the first pipe may be inserted into the receiving hole and fixed to the first pipe with an adhesive.

The shaft member 30 has a core material 31 and a first screw 32 and a second screw 33 located at both ends of the core material 31 and having a larger diameter than the core material 31. Thus, the shaft member 30, which has the first screw 32 and the second screw 33 at both ends and the relatively small-diameter core material 31 in the center, is formed by, for example, rolling.

The first cotter 40 has a second hollow portion 41 inside and a second screw groove 42 at its end.

A portion of the first pipe 20 is accommodated in the second hollow portion 41 of the first cotter 40, the shaft member 30 is accommodated in the second hollow portion 41 and the first hollow portion 21, the first thread groove 22 of the first pipe 20 is screwed into the first screw 32 of the shaft member 30, and the second thread groove 42 of the first cotter 40 is screwed into the second screw 33 of the shaft member 30.

A portion of the first cotter 40 protrudes outside the wooden body 10, and a pivot piece 60 is attached to a fixing jig 45 at the end of the first cotter 40. This pivot piece 60 is a member that is rotatably attached to a connecting jig that is connected to the building frame, as described below.

In the shaft member 30, the core material 31 has a smaller diameter than the first screw 32 and the second screw 33. Therefore, in the first hollow portion 21 of the first pipe 20, a gap G1 is formed between the core material 31 and the wall surface of the first hollow portion 21, which allows buckling of the core material 31.

In addition, a hexagonal nut 35 is fixed to the entrance region of the second hollow portion 41 in the core material 31, and the hexagonal nut 35 is in sliding contact with the wall surface of the second hollow portion 41.

In the second hollow portion 41, a gap G3 (width t1) is provided between the hexagonal nut 35 and the bottom of the countersink of the second hollow portion 41 to allow for deformation margins for buckling deformation of the core material 31.

A steel second pipe 50 is provided around the first pipe 20, axially inward of the first cotter 40, with a gap G2 (width t1) for the wooden body 10 to deform. In other words, the inner diameter of the second pipe 50 is larger than the outer diameter of the first pipe 20.

As shown in Figure 2, when a compressive force N1 acts on the wooden shaft member 80, the wooden body 10 is pushed axially inward, eliminating the deformation-substituting gaps G2 and G3 shown in Figure 1. If the applied compressive force N1 is greater than the buckling strength of the core material 31, the core material 31 buckles and deforms in the gap G1 of the first hollow portion 21, abutting against the wall surface of the first hollow portion 21 and restraining further deformation. Depending on the amount of compressive deformation of the wooden body 10, the deformation-substituting gaps G2 and G3 may not completely disappear as in the illustrated example, but may remain slightly.

In this way, when a compressive force N1 acts on the wooden body 10 and the connecting fitting 15 during an earthquake, the core material 31 of the shaft member 30 that constitutes the connecting fitting 15 buckles and deforms, effectively absorbing the strain energy during the earthquake. In this case, the first screw 32 and second screw 33 of the shaft member 30, which are larger in diameter than the central core material 31, are fixed to the first pipe 20 and first cotter 40 at both ends of the core material 31, respectively. Therefore, the first screw 32 and second screw 33 do not break first in response to the compressive force N1, and the core material 31 buckles and deforms.

Furthermore, when the core material 31 buckles, the first pipe 20 and the first cotter 40 are located on the outer periphery of the core material 31, and the wooden body 10 is located on the outer periphery of the first pipe 20 and the first cotter 40. Therefore, even though the core material 31 buckles in the first hollow portion 21 of the first pipe 20 and the second hollow portion 41 of the first cotter 40, it is restrained by the first pipe 20, the first cotter 40, and the wooden body 10, preventing buckling failure of the core material 31.

Furthermore, a steel second pipe 50 is provided around the first pipe 20, axially inward of the first cotter 40 on the wooden body 10. This allows the second pipe 50 to press down on the first pipe 20, preventing cracks that may occur in the wooden body 10, such as firewood splitting, originating from the first cotter 40, and preventing the wooden body 10 from opening due to such cracks.

On the other hand, as shown in Figure 3, when a tensile force N2 acts on the wooden body 10 and the connecting fitting 15, the wooden body 10 is pulled axially outward, the width dimension of the deformation-substituting gap G2 increases to t2 (> t1), and the first cotter 40 protrudes further outward from the end 11 of the wooden body 10.

Furthermore, if the applied tensile force N2 is greater than the tensile strength of the core material 31, the core material 31 will deform in the tensile direction, thereby absorbing strain energy during an earthquake.

In this way, the wooden main body 10 and the building frame are connected via a metal joint 15 that exhibits deformation performance in both tension and compression, allowing the wooden shaft member 80 with spindle-shaped hysteresis characteristics to be incorporated as a wooden brace.

[Wood shaft member according to the second embodiment]
Next, an example of a wooden shaft member according to a second embodiment will be described with reference to Fig. 4. Here, Fig. 4 is a vertical cross-sectional view of an example of a wooden shaft member according to the second embodiment.

The wooden shaft member 80A differs from the wooden shaft member 80 in that it has a connector 15A equipped with a second cotter 70 instead of the connector 15 equipped with a first cotter 40 and a second pipe 50.

The connecting fitting 15A has a first steel pipe 20, a second steel cotter 70, and a steel shaft member 30.

The steel second cotter 70 has a third pipe 71 with a third hollow portion 73 and a disk 72, with one end of the third pipe 71 welded to one side of the disk 72.

A third screw groove 74 is formed in the disk 72, and one end of the shaft member 30 inserted into the first hollow portion 21 of the first pipe 20 is inserted into the third hollow portion 73, with the second screw 33 threaded into the third screw groove 74 while protruding outward from the end portion 11 of the wooden body 10.

A gap G4 is provided at the end of the third pipe 71 in the wooden body 10 to allow for deformation of the wooden body 10 when the wooden body 10 is compressed and deformed. Furthermore, a gap G5 is provided between the end 11 of the wooden body 10 in the third pipe and the disk 72 to allow for deformation of the wooden body 10.

With the wooden shaft member 80A equipped with the connecting fitting 15A, at least a portion of the third pipe 71 provided on the second cotter 70 is embedded in the end of the wooden main body 10, and the core material 31 extends outward from the end 11 of the wooden main body 10 and is screwed to the second cotter 70. This allows the third pipe 71 to exert buckling stiffness together with the wooden main body 10 when the core material 31 buckles.

In addition, because the third pipe 71 presses against the periphery of the first pipe 20, it is possible to prevent cracking of the wooden body 10 that may occur starting from the second cotter 70. Furthermore, because the connecting fitting 15A has both the ability to stiffen the wooden body 10 against buckling and the ability to prevent cracking of the wooden body 10, there is no need to use separate components that have both functions, which makes it possible to reduce manufacturing costs.

[Building frame according to the embodiment]
Next, several examples of building frames according to the embodiment will be described with reference to Fig. 5 and Fig. 6. Here, Fig. 5(a) to Fig. 5(e) are schematic diagrams showing examples of building frames according to the embodiment, and Fig. 6 is a front view specifically showing the building frame shown in Fig. 5(d).

In each building frame shown in Figure 5, the wooden shaft member 80 (80A) is incorporated into the frame as a wooden brace. The beams 91 and columns 93 that make up each building frame may be wooden members, steel members, or reinforced concrete members. Furthermore, as long as the building frame is equipped with at least the wooden brace 80 (80A), it may be in a form other than the example shown.

The K-shaped building frame 100A shown in Figure 5(a) has a beam 91 and two columns 93 that support the beam 91, with two wooden braces 80 (80A) attached to connect the bottom ends of each column 93 to the center of the beam 91.

The building frame 100B shown in Figure 5(b) is an irregular K-shaped structure, with a beam 91 and two columns 93 supporting the beam 91, and two wooden braces 80 (80A) attached to connect the bottom ends of each column 93 to the left and right sides of the beam 91.

The knee-braced building frame 100C shown in Figure 5(c) has a beam 91 and two columns 93 that support the beam 91, with two wooden braces 80 (80A) attached so as to connect the upper ends of each column 93 to the left and right ends of the beam 91.

The single-braced building frame 100D shown in Figure 5(d) has a beam 91 and two columns 93 supporting the beam 91, with one wooden brace 80 (80A) attached to connect the upper end of one column 93 to the lower end of the other column 93.

The building frame 100E shown in Figure 5(e) is a K-type structure inverted by 90 degrees, and has a beam 91 and two columns 93 supporting the beam 91, with two wooden braces 80 (80A) attached to connect the upper and lower ends of one column to the center of the other column.

Figure 6 specifically illustrates the building frame 10D shown in Figure 5(d), and also shows the base 92 as a component of the building frame.

Connecting jigs 95, such as brackets, are attached via bolts or the like to the upper right and lower left joints of the beams 91 and columns 93, which form a rectangular frame when viewed from the front. The pivot pieces 60 at both ends of the wooden brace 80 (80A) are attached to each connecting jig 95 with bolts and nuts 96.

The building frames 100A to 100E shown in the figures use wooden shaft members 80 (80A) as wooden braces, resulting in excellent deformation performance in both compression and tension at the joints between the columns 93 or beams 91 and the wooden braces 80 (80A), resulting in a building frame with excellent strain energy absorption performance during an earthquake. Furthermore, the deformation performance of the wooden braces 80 (80A) prevents a sudden increase in load at the joints between the columns 93 or beams 91 and the wooden braces 80 (80A) when external forces are applied during an earthquake.

Furthermore, since most of the metal joints 15, 15A are embedded inside the wooden body 10, the entire metal cannot be seen from the outside, resulting in a building frame with wooden braces that has excellent exterior design.

Note that other embodiments may be possible in which other components are combined with the configurations described in the above embodiments, and the present invention is in no way limited to the configurations shown here. In this regard, changes can be made without departing from the spirit of the present invention, and can be determined appropriately depending on the application form.

10: Wooden body 11: End 12: Receiving hole 15, 15A: Joint fitting 20: First pipe 21: First hollow portion 22: First screw groove 23: Threaded peripheral surface (periphery)
30: Shaft member 31: Core material 32: First screw 33: Second screw 35: Hexagonal nut 40: First cotter 41: Second hollow portion 42: Second screw groove 45: Fixing jig 50: Second pipe 60: Rotating piece 70: Second cotter 71: Third pipe 72: Disk 73: Third hollow portion 74: Third screw groove 80, 80A: Wooden shaft member (wooden brace)
91: Beam 92: Foundation 93: Pillar 95: Connection jig 96: Bolt and nut 100A, 100B, 100C, 100D, 100E: Building frame G1: Gap G2, G3, G4, G5: Gap for deformation substitution N1: Compressive force N2: Tensile force

Claims (8)

a wooden body having a receiving hole at an end thereof;
a metal fitting embedded in the receiving hole,
The connecting fitting is
a first pipe made of steel, the first pipe having a first hollow portion therein and a first thread groove at one end of the first hollow portion;
a steel shaft member including a steel core material and a first screw and a second screw located at both ends of the core material and having a diameter larger than that of the core material;
a first steel cotter having a second hollow portion therein and a second thread groove;
a part of the first pipe is accommodated in the second hollow portion, the shaft member is accommodated in the second hollow portion and the first hollow portion, the first screw groove and the first screw are screw-fixed, and the second screw groove and the second screw are screw-fixed,
A wooden shaft member characterized in that a second steel pipe is provided around the first pipe and axially inside the wooden body relative to the first cotter. A second pipe is provided at the end of the first cotter via a gap for allowing deformation of the wooden body.
2. The wooden shaft member according to claim 1, wherein the second hollow portion of the first cotter is provided with a gap for allowing deformation of the core material. a wooden body having a receiving hole at an end thereof;
a metal fitting embedded in the receiving hole,
The connecting fitting is
a first pipe made of steel, the first pipe having a first hollow portion therein and a first thread groove at one end of the first hollow portion;
a steel shaft member including a steel core material and a first screw and a second screw located at both ends of the core material and having a diameter larger than that of the core material;
a second steel cotter having a third steel pipe and a third thread groove ;
At least a part of the third pipe is buried in an end of the wood body, the first pipe is disposed inside the third pipe , and the first screw is screw-fixed to the first screw groove.
A gap is provided at the end of the third pipe to allow for deformation of the wooden body,
A wooden shaft member characterized in that the core material extends outward from the end of the wooden body, and the second screw of the core material is screwed into the third screw groove of the second cotter. The receiving hole is a threaded hole, and the first pipe has a threaded circumferential surface.
4. The wooden shaft member according to claim 1, wherein the first pipe is threadedly engaged with the receiving hole. A wooden shaft member according to any one of claims 1 to 3, characterized in that the storage hole and the first pipe are fixed together via an adhesive. A wooden shaft member as described in claim 1 or 2, characterized in that a rotating piece that is freely rotatably attached to a connecting jig connected to a building frame is directly or indirectly attached to the outer end of the first cotter. A wooden shaft member as described in claim 3, characterized in that a rotating piece that is freely rotatably attached to a connecting jig connected to a building frame is directly or indirectly attached to the outer end of the second cotter. A wooden brace comprising the wooden shaft member according to claim 6 or 7 , a beam, and a column,
A building frame, characterized in that the wooden braces are connected to the beams and the columns.