Earthquake-resistant structure of wooden buildings

Abstract

Compared to using conventional washers, this method makes it possible to increase the restoring force of the second material against forces that attempt to tilt it in the range of large deformation angles. [Solution] The seismic-resistant structure of the wooden building comprises a foundation, anchor bolts 11, wooden columns 20, and a cylindrical metal damper 30. The column 20 has an insertion hole 23 through which the anchor bolt 11 is inserted, a first recess 21 that opens on the side and communicates with the tip of the insertion hole 23, and a second recess 22 located above the first recess 21, which opens on the side and communicates with the first recess 21. Both ends of the second recess 22 in the width direction W are located further out than both ends of the first recess 21 in the width direction W. The damper 30 is housed in the second recess 22 and is configured to be immovable in the vertical direction Z by contacting the second recess 22, has a through hole 31 through which the anchor bolt 11 passes, and is fixed to the anchor bolt 11 by a nut 40.

Description

Technical Field

[0001] The present invention relates to a seismic structure for wooden buildings.

Background Art

[0002] In wooden buildings, as shown in FIG. 6, there is a case where a wooden column 120 is fixed to a foundation via an anchor bolt 111 protruding upward from a foundation (not shown) (see, for example, Patent Document 1). The column 120 has an insertion hole 123 through which the anchor bolt 111 is inserted. The column 120 has a hole 122 that opens on the side surface and communicates with the insertion hole 123. A nut 140 is screwed onto the upper end portion of the anchor bolt 111 exposed inside the hole 122. Also, a flat washer 130 is disposed between the nut 140 and the bottom surface of the hole 122.

[0003] In such a conventional wooden building, when a force acts to tilt the column due to an earthquake, the force is transmitted from the bottom surface of the hole 122 to the nut 140 via the washer 130.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the force trying to tilt the column becomes large, the washer 130 sinks into the bottom surface of the hole 122 and the destruction of the column 120 progresses. Therefore, in a region where the deformation angle, which is the magnitude of the tilt of the column 120, is large, the restoring force of the column 120 against the force trying to tilt the column 120 becomes low, and the column 120 cannot be restored to a vertical posture. As a result, the building is likely to collapse.

Means for Solving the Problems

[0006] This section describes various types of earthquake-resistant structures for wooden buildings that address the above-mentioned problems. [Aspect 1] The first member is either a foundation, a wooden column, or a wooden horizontal member, A bolt protruding upward or sideways from the first material, A second member which is either a wooden column or a wooden horizontal member, extends along the bolt and is fixed to the first member via the bolt, It is equipped with a cylindrical metal damper, The second material is, An insertion hole extending along the extending direction of the second material and through which the bolt is inserted, A first recess that opens on the side and communicates with the tip of the insertion hole, The second material has a second recess located on the opposite side of the insertion hole from the first recess in the extending direction of the second material, which opens to the side surface and communicates with the first recess, Both ends of the second recess in the width direction of the side surface are located further out than both ends of the first recess in the width direction. The damper is housed within the second recess and is configured to be immovable in the extending direction of the second material by contacting the second recess, and has a through hole through which the bolt passes and is fixed to the bolt by a nut. Earthquake-resistant structure for wooden buildings.

[0007] In this embodiment, a cylindrical metal damper is housed within a second recess of the second material. The damper is configured to be immovable in the extending direction of the second material by contacting the second recess. A bolt protruding from the first material is inserted through a through hole in the second material and also through a through hole in the damper, and is fixed to the damper with a nut. Therefore, when an earthquake causes a force to tilt the second material relative to the first material, that is, a force to separate the second material from the first material, this force is transmitted to the portion of the damper adjacent to the first recess. As a result, the damper acts as a resistance element against the force, and the force is attenuated by the deformation of the portion of the damper adjacent to the first recess so as to bulge out toward the first recess. In other words, since the force is consumed by deforming the damper itself, the damper is prevented from sinking into the wooden second material and destroying the second material.

[0008] Therefore, compared to using conventional washers, it is possible to increase the restoring force of the second material against forces that attempt to tilt it in the range of large deformation angles. [Aspect 2] The first recess has a rectangular parallelepiped-shaped receiving space formed between two first inner surfaces that extend along the extending direction of the second material. The second recess has a rectangular parallelepiped-shaped receiving space formed between two second inner surfaces that extend along the extending direction of the second material. The damper is rectangular in shape. The earthquake-resistant structure for a wooden building as described in Embodiment 1.

[0009] With this configuration, the damper is rectangular in shape, which simplifies its design. Therefore, the damper can be easily manufactured. [Aspect 3] The first material is the foundation, The bolt is an anchor bolt that protrudes upward from the first material. The second member is a column, The first recess and the second recess are provided in the column base portion of the second member. The seismic structure of the wooden building according to Embodiment 1 or Embodiment 2.

[0010] According to this configuration, compared with the case of using a conventional washer, it is possible to increase the restoring force of the column fixed to the anchor bolt protruding from the foundation in the region of a large deformation angle.

Effect of the Invention

[0011] According to the present invention, compared with the case of using a conventional washer, it is possible to increase the restoring force of the second member against the force that tries to tilt the second member in the region of a large deformation angle.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a cross-sectional view of a foundation and a column base portion in an embodiment of the seismic structure of a wooden building. [Figure 2] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. [Figure 3] FIG. 3 is a perspective view of the damper of FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view of a foundation and a column base portion, showing a cross-sectional view of the damper after deformation. [Figure 5] FIG. 5 is a graph showing the relationship between the deformation angle of the column and the horizontal force. [[ID=3३]] [Figure 6] FIG. 6 is a cross-sectional view of a conventional column. [Figure 7] FIG. 7 is a cross-sectional view of a column and a horizontal member in a modified example of the seismic structure of a wooden building. [[ID=५1]]

Mode for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the seismic structure of a wooden building will be described with reference to FIGS. 1 to 6. As shown in FIG. 1, the seismic structure of the wooden building includes a foundation 10, an anchor bolt 11, a column 20, a damper 30, and a nut 40.

[0014] <Foundation 10 and Anchor Bolt 11> As shown in Figure 1, the foundation 10 is made of concrete. As shown in Figures 1 and 2, the anchor bolts 11 protrude upward from the foundation 10. The anchor bolts 11 are made of steel. It is preferable that, for example, two or four anchor bolts 11 are provided for one column 20. In this embodiment, two anchor bolts 11 are provided for one column 20.

[0015] <Column 20> As shown in Figures 1 and 2, the column 20 is made of wood. The column 20 extends along the anchor bolts 11, that is, along the vertical direction Z, and is fixed to the foundation 10 via the anchor bolts 11. In this embodiment, the column 20 is a rectangular column with a square cross-section. However, the column 20 may also be a round column with a circular cross-section.

[0016] The column 20 has an insertion hole 23, a first recess 21, and a second recess 22. One set of the insertion hole 23, the first recess 21, and the second recess 22 is provided for one anchor bolt 11. In other words, in this embodiment, two sets of the insertion hole 23, the first recess 21, and the second recess 22 are provided.

[0017] The through-hole 23 extends along the extending direction of the column 20, that is, along the vertical direction Z. An anchor bolt 11 is inserted through the through-hole 23. In this embodiment, two through-holes 23 are provided so as to sandwich the central axis of the column 20. The through-hole 23 is a circular hole.

[0018] The first recess 21 and the second recess 22 are provided at the base of the column 20. As shown in Figure 1, the first recess 21 opens into the side surface 20a of the column 20 and communicates with the tip, i.e., the upper end, of the insertion hole 23.

[0019] In the following explanation, the width direction of the side surface 20a will simply be referred to as the width direction W. Furthermore, the direction perpendicular to both the vertical direction Z and the width direction W will be referred to as the depth direction D. As shown in Figures 1 and 2, the first recess 21 has a rectangular parallelepiped-shaped storage space formed between two first inner surfaces 21b that extend along the vertical direction Z. More specifically, the first recess 21 has two first inner surfaces 21b that face each other in the width direction W, and a first bottom surface 21a that connects the lower ends of the first inner surfaces 21b.

[0020] The first inner surface 21b extends along both the vertical direction Z and the depth direction D. The first bottom surface 21a extends along both the width direction W and the depth direction D. That is, the first bottom surface 21a extends perpendicular to the vertical direction Z. The insertion hole 23 is opened in the first bottom surface 21a.

[0021] The second recess 22 is located on the opposite side of the insertion hole 23 in the vertical direction Z, with the first recess 21 in between, i.e., on the upper side. As shown in Figure 1, the second recess 22 opens into the side surface 20a of the column 20 and communicates with the first recess 21.

[0022] As shown in Figures 1 and 2, the second recess 22 has a rectangular parallelepiped-shaped storage space formed between two second inner surfaces 22b that extend along the vertical direction Z. More specifically, as shown in Figure 2, the second recess 22 has two second inner surfaces 22b facing each other in the width direction W, two second bottom surfaces 22a connected to the lower ends of the second inner surfaces 22b, and a second top surface 22c connecting the upper ends of the second inner surfaces 22b.

[0023] The second inner surface 22b extends along both the vertical direction Z and the depth direction D. The second bottom surface 22a and the second top surface 22c extend along both the width direction W and the depth direction D. That is, the second bottom surface 22a and the second top surface 22c extend perpendicular to the vertical direction Z.

[0024] As shown in Figure 2, both ends of the second recess 22 in the width direction W are located further out than both ends of the first recess 21 in the width direction W. The first recess 21 opens between the two second bottom surfaces 22a. In this embodiment, the first recess 21 and the second recess 22 have symmetrical shapes in the width direction W.

[0025] <Damper 30 and nut 40> As shown in Figures 1 to 3, the damper 30 is a cylindrical metal unit housed within the second recess 22. The damper 30 in this embodiment is made of steel.

[0026] As shown in Figure 3, the damper 30 of this embodiment is rectangular in shape. The damper 30 has a lower wall 30a that abuts against the second bottom surface 22a of the second recess 22, two side walls 30b that abut against the two second inner surfaces 22b, and an upper wall 30c that abuts against the second top surface 22c. The damper 30 is open on both sides in the depth direction D. The lower wall 30a, the two side walls 30b, and the upper wall 30c of this embodiment are all square in shape.

[0027] The damper 30 is configured to be immovable in the vertical direction Z by contacting the second recess 22. The damper 30 has a through hole 31 through which the anchor bolt 11 passes. The through hole 31 is a circular hole (see Figure 3).

[0028] The damper 30 is fixed to the anchor bolt 11 by nuts 40. Two nuts 40 sandwich the damper 30. In this embodiment, the foundation 10, anchor bolts 11, and columns 20 correspond to the first material, bolts, and second material, respectively, in the [Means for Solving the Problem] section.

[0029] <Operation of this embodiment> As shown in Figure 2, a cylindrical metal damper 30 is housed in the second recess 22 of the column 20. The damper 30 is configured to be immovable in the vertical direction Z by abutting against the second recess 22. An anchor bolt 11 protruding from the foundation 10 is inserted through the insertion hole 23 of the column 20 and also passes through the through hole 31 of the damper 30, and is fixed to the damper 30 by a nut 40. Therefore, when an earthquake acts to tilt the column 20 relative to the foundation 10, that is, when a force acts to separate the column 20 from the foundation 10, this force is transmitted to the lower wall 30a, which is the part of the damper 30 adjacent to the first recess 21.

[0030] As a result, as shown in Figure 4, the damper 30 acts as a resistance element against the force, and the force is attenuated by the deformation of the lower wall 30a of the damper 30 so as to bulge out toward the first recess 21. In other words, since the force is consumed by deforming the damper 30 itself, the damper 30 is prevented from sinking into the second bottom surface 22a of the wooden column 20 and from destroying the column 20.

[0031] <Relationship between column deformation angle and horizontal force in examples and comparative examples> Next, referring to Figure 5, we will explain the relationship between the deformation angle θ (rad) of the column and the horizontal force p (kN) acting on the column, that is, the restoring force of the column against the force that tries to tilt the column.

[0032] In Figure 5, the solid line represents the measurement results for the seismic-resistant structure of the wooden building in the example, and the dashed line represents the measurement results for the seismic-resistant structure of the wooden building in the comparative example. The seismic-resistant structure of the wooden building in the comparative example is a structure using washer 130 as shown in Figure 6.

[0033] The cross-section of the column 20 in this embodiment is a square with sides of 300 mm. The length of the column 20 is 6000 mm. The lower wall 30a, side wall 30b, and upper wall 30c of the damper 30 are all squares with sides of 75 mm. The thickness of the lower wall 30a, side wall 30b, and upper wall 30c is 3.2 mm.

[0034] The cross-section of the comparative example column 120 is a square with sides of 300 mm. The length of column 120 is 6000 mm. The washer 130 is a square with sides of 75 mm. The thickness of washer 130 is 3.2 mm.

[0035] As shown by the dashed line in Figure 5, in the comparative example, in the region where the deformation angle θ is from 0 to 0.015, the horizontal force p increases sharply with increasing deformation angle θ. In the region where the deformation angle θ is from 0.015 to 0.024, the horizontal force p decreases sharply with increasing deformation angle θ. Furthermore, in the region where the deformation angle θ is greater than 0.024, the horizontal force p decreases gradually with increasing deformation angle θ.

[0036] In the region where the deformation angle θ is between 0.015 and 0.024, the washer 130 was driven into the bottom of the hole 122 by a force attempting to tilt the column 120, and the failure of the column 120 progressed. As a result, the horizontal force p decreased rapidly as the deformation angle θ increased.

[0037] As shown by the solid line in Figure 5, in the embodiment, the horizontal force p increases with increasing deformation angle θ in the region from 0 to 0.06. In the region where the deformation angle θ is less than 0.024, the horizontal force p is smaller than in the comparative example, but in the region where it is 0.024 or greater, the horizontal force p is larger than in the comparative example.

[0038] In the region where the deformation angle θ is between 0 and 0.06, the lower wall 30a of the damper 30 bulged outwards toward the first recess 21 due to the force attempting to tilt the column 20, and it is thought that the horizontal force p increased with increasing deformation angle θ.

[0039] <Effects of this embodiment> (1) The seismic-resistant structure of the wooden building comprises a foundation 10, anchor bolts 11, wooden columns 20, and a cylindrical metal damper 30. The column 20 has an insertion hole 23, a first recess 21, and a second recess 22. Both ends of the second recess 22 in the width direction W of the side surface 20a are located further out than both ends of the first recess 21 in the width direction W. The damper 30 is housed in the second recess 22 and is configured to be immovable in the extending direction of the column 20 by contacting the second recess 22. The damper 30 has a through hole 31 through which the anchor bolt 11 passes and is fixed to the anchor bolt 11 by a nut 40.

[0040] With this configuration, the effects of the embodiment described above are achieved, making it possible to increase the restoring force of the column 20 against forces that attempt to tilt the column 20 in the range of large deformation angles, compared to the case where a conventional washer 130 is used.

[0041] (2) The first recess 21 has a rectangular parallelepiped-shaped accommodating space formed between two first inner surfaces 21b that extend along the extending direction of the column 20. The second recess 22 has a rectangular parallelepiped-shaped accommodating space formed between two second inner surfaces 22b that extend along the extending direction of the column 20. The damper 30 is rectangular tubular.

[0042] With this configuration, since the damper 30 is rectangular in shape, the shape of the damper 30 becomes simple. Therefore, the damper 30 can be easily manufactured. <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0043] The number of anchor bolts 11 provided on a single column 20 is not limited to two. For example, if four anchor bolts 11 are provided, four sets of through holes 23, first recesses 21, and second recesses 22 should be provided, corresponding to the number of anchor bolts 11. In this case, it is preferable that the anchor bolts 11 be provided at 90-degree intervals around the central axis of the column 20. Also, if the column 20 is thin, one anchor bolt 11 may be provided so as to pass through the central axis of the column 20.

[0044] The shape of the damper 30 is not limited to a rectangular tube. For example, if the second recess 22 has a cylindrical housing space that extends along the depth direction D, the damper 30 can also be made cylindrical.

[0045] In the above embodiment, the first member, bolt, and second member were embodied as the foundation 10, anchor bolt 11, and column 20, respectively, but the present invention is not limited thereto. For example, the first member could be a horizontal member, and the second member could be a column extending upward from the horizontal member.

[0046] As shown in Figure 7, the first member can be a wooden column 210, and the second member can be a wooden horizontal member 220 extending laterally from the column 210. In this case, the bolt 211 protrudes laterally from the column 210. The horizontal member 220 extends along the bolt 211 and is fixed to the column 210 via the bolt 211. The horizontal member 220 is provided with a first recess 221, a second recess 222, and an insertion hole 223. The damper 30 is housed in the second recess 222 and is configured to be immovable in the direction of extension of the horizontal member 220, i.e., in the horizontal direction, by abutting against the second recess 222. Note that the damper 30 has the same configuration as in the above embodiment, so its description will be omitted. [Explanation of Symbols]

[0047] 10…Basics 11,111… Anchor bolts 20,120... pillars 20a...side 21…First recess 21a…1st bottom surface 21b…First inner surface 22...Second recess 22a…Second bottom surface 22b…Second inner surface 22c…Second top surface 23,123… Through holes 30... Damper 30a…Lower wall 30b…Side wall 30c…Top wall 31…Through hole 40,140...nuts 122... Hole 130... Washer 210... pillars 211... Bolts 220... Horizontal structural members 221...First recess 222...Second recess 223... Through hole

Claims

1. The first member is either a foundation, a wooden column, or a wooden horizontal member, A bolt protruding upward or sideways from the first material, A second member which is either a wooden column or a wooden horizontal member, extends along the bolt and is fixed to the first member via the bolt, It is equipped with a cylindrical metal damper, The second material is, An insertion hole extending along the extension direction of the second material and through which the bolt is inserted, A first recess that opens on the side and communicates with the tip of the insertion hole, The second material has a second recess located on the opposite side of the insertion hole from the first recess in the extending direction of the second material, which opens to the side surface and communicates with the first recess, Both ends of the second recess in the width direction of the side surface are located further out than both ends of the first recess in the width direction. The damper is housed within the second recess and is configured to be immovable in the extending direction of the second material by contacting the second recess, and has a through hole through which the bolt passes and is fixed to the bolt by a nut. Earthquake-resistant structure for wooden buildings.

2. The first recess has a rectangular parallelepiped-shaped receiving space formed between two first inner surfaces that extend along the extending direction of the second material. The second recess has a rectangular parallelepiped-shaped receiving space formed between two second inner surfaces that extend along the extending direction of the second material. The damper is rectangular in shape. The earthquake-resistant structure for a wooden building as described in claim 1.

3. The first material is the foundation, The bolt is an anchor bolt that protrudes upward from the first material. The second member mentioned above is a column, The first recess and the second recess are provided in the column base portion of the second member. An earthquake-resistant structure for a wooden building according to claim 1 or claim 2.

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