Earthquake-resistant structure of wooden buildings

Abstract

Compared to the case where a conventional general washer is used, it is possible to increase the restoring force of the second material against a force that tends to tilt the second material in the region of large deformation angles. [Solution] The earthquake-resistant structure of a wooden building includes a foundation, anchor bolts (11), wooden pillars (20), and a cylindrical metal damper (30). The pillars (20) have an insertion hole (23) through which the anchor bolts (11) are inserted, a first recess (21) that opens to the side and communicates with the tip of the insertion hole (23), and a second recess (22) located above the first recess (21), that opens to the side and communicates with the first recess (21). Both ends of the second recess (22) in the width direction (W) are located outside both ends of the first recess (21) in the width direction (W). The damper (30) is housed within the second recess (22) and abuts against the second recess (22), making it immovable in the vertical direction (Z). The damper (30) has a through hole (31) through which the anchor bolt (11) passes and is fixed to the anchor bolt (11) with a nut (40).

Description

[Technical Field]

[0001] The present invention relates to earthquake-resistant structures for wooden buildings. [Background technology]

[0002] In some wooden buildings, as shown in Fig. 6, a wooden pillar 120 is fixed to a foundation via an anchor bolt 111 that protrudes upward from the foundation (not shown) (see, for example, Patent Document 1). The pillar 120 has an insertion hole 123 through which the anchor bolt 111 is inserted. The pillar 120 has a hole 122 that opens to the side and communicates with the insertion hole 123. A nut 140 is threaded onto the upper end of the anchor bolt 111 that is exposed inside the hole 122. 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 an earthquake causes a force to tilt the pillar, the force is transmitted from the bottom of the hole 122 to the nut 140 via the washer 130 . [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-62775 Summary of the Invention [Problem to be solved by the invention]

[0005] When the force tending to tilt the pillar increases, the washer 130 sinks into the bottom surface of the hole 122, and the destruction of the pillar 120 progresses. For this reason, in an area where the deformation angle, which is the magnitude of the tilt of the pillar 120, is large, the restoring force of the pillar 120 against the force tending to tilt the pillar 120 decreases, and the pillar 120 is no longer able to return to a vertical position. As a result, the building becomes more susceptible to collapse. [Means for solving the problem]

[0006] Various aspects of earthquake-resistant structures for wooden buildings to solve the above problems will be described below. [Aspect 1] a first member that is one of a foundation, a wooden column, and a wooden cross member; a bolt protruding upward or laterally from the first member; A second member is either a wooden pillar or a wooden cross member, and extends along the bolt and is fixed to the first member via the bolt; A metal cylindrical damper is provided. 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 to a side surface and communicates with a tip of the insertion hole; a second recess portion that is located on the opposite side of the insertion hole with the first recess portion in the extending direction of the second material, the second recess portion being open to the side surface and communicating with the first recess portion, both ends of the second recess in the width direction of the side surface are located outside both ends of the first recess in the width direction, The damper is accommodated in the second recess and abuts against the second recess so as to be immovable in the extension direction of the second material, has a through hole through which the bolt passes, and is fixed to the bolt by a nut. Earthquake-resistant structure of wooden buildings.

[0007] According to this embodiment, a cylindrical metal damper is housed in the second recess of the second material. The damper is immobilized in the extension direction of the second material by abutting against the second recess. A bolt protruding from the first material is inserted into an insertion hole in the second material, passes through a through-hole in the damper, and is fixed to the damper with a nut. Therefore, when an earthquake causes a force that tilts the second material relative to the first material, i.e., a force that moves the second material away from the first material, the force is transmitted to the portion of the damper adjacent to the first recess. This not only serves as a resistance element against the force, but also attenuates the force by deforming the portion of the damper adjacent to the first recess so that it bulges toward the first recess. In other words, the force is consumed in deforming the damper itself, preventing the damper from sinking into the second wooden material and destroying the second material.

[0008] Therefore, compared to when a conventional general washer is used, it is possible to increase the restoring force of the second material against a force that tends to tilt the second material in a large deformation angle range. [Aspect 2] the first recess has a rectangular parallelepiped accommodation space formed between two first inner surfaces extending along the extension direction of the second material, the second recess has a rectangular parallelepiped accommodation space formed between two second inner surfaces extending along the extension direction of the second material, The damper is a square tube. The earthquake-resistant structure of the wooden building according to aspect 1.

[0009] According to this configuration, the damper has a rectangular cylindrical shape, which simplifies the shape of the damper, making it easy to form the damper. [Aspect 3] The first material is a foundation, The bolt is an anchor bolt protruding upward from the first material, The second material is a pillar, The first recess and the second recess are provided in a base portion of the second material. An earthquake-resistant structure of a wooden building according to aspect 1 or aspect 2.

[0010] According to this configuration, it is possible to increase the restoring force of a column fixed to an anchor bolt protruding from the foundation in a large deformation angle range compared to when a conventional general washer is used. [Effects of the Invention]

[0011] According to the present invention, it is possible to increase the restoring force of the second material against a force tending to tilt the second material in a large deformation angle range, compared to when a conventional general washer is used. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view of a foundation and a column base in an embodiment of an earthquake-resistant structure for a wooden building. [Figure 2] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. [Figure 3] FIG. 3 is a perspective view of the damper of FIG. [Figure 4] FIG. 4 is a cross-sectional view of the foundation and the column base, showing the damper after deformation. [Figure 5] Figure 5 is a graph showing the relationship between the column deformation angle and horizontal force. [Figure 6] FIG. 6 is a cross-sectional view of a conventional pillar. [Figure 7] FIG. 7 is a cross-sectional view of columns and cross members in a modified example of the earthquake-resistant structure of a wooden building. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, one embodiment of an earthquake-resistant structure for a wooden building will be described with reference to FIGS. As shown in FIG. 1, the earthquake-resistant structure of a wooden building includes a foundation 10, anchor bolts 11, columns 20, dampers 30, and nuts 40.

[0014] <Foundation 10 and anchor bolts 11> As shown in FIG. 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> 1 and 2, the pillar 20 is made of wood. The pillar 20 extends along the anchor bolts 11, i.e., in the vertical direction Z, and is fixed to the foundation 10 via the anchor bolts 11. The pillar 20 in this embodiment is a rectangular pillar with a square cross section. However, the pillar 20 may also be a round pillar with a circular cross section.

[0016] The pillar 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. That is, in this embodiment, two sets of the insertion hole 23, the first recess 21, and the second recess 22 are provided.

[0017] The insertion holes 23 extend along the extension direction of the pillar 20, i.e., along the up-down direction Z. An anchor bolt 11 is inserted into the insertion holes 23. In this embodiment, two insertion holes 23 are provided on either side of the central axis of the pillar 20. The insertion holes 23 are circular holes.

[0018] The first recess 21 and the second recess 22 are provided in the base of the pillar 20. As shown in FIG. 1, the first recess 21 opens to the side surface 20a of the pillar 20 and communicates with the tip of the insertion hole 23, that is, the upper end.

[0019] In the following description, the width direction of the side surface 20a will be simply referred to as the width direction W. Furthermore, the direction perpendicular to both the up-down direction Z and the width direction W will be referred to as the depth direction D. 1 and 2, the first recess 21 has a rectangular parallelepiped storage space formed between two first inner sides 21b extending along the up-down direction Z. More specifically, the first recess 21 has two first inner sides 21b facing each other in the width direction W, and a first bottom surface 21a connecting the lower ends of the first inner sides 21b.

[0020] The first inner side surface 21b extends along both the up-down direction Z and the depth direction D. The first bottom surface 21a extends along both the width direction W and the depth direction D. In other words, the first bottom surface 21a extends perpendicular to the up-down direction Z. The insertion hole 23 opens in the first bottom surface 21a.

[0021] The second recess 22 is located on the opposite side of the first recess 21 in the vertical direction Z from the insertion hole 23, that is, on the upper side. As shown in FIG. 1, the second recess 22 opens to the side surface 20a of the pillar 20 and communicates with the first recess .

[0022] 1 and 2, the second recess 22 has a rectangular parallelepiped storage space formed between two second inner sides 22b extending along the up-down direction Z. More specifically, as shown in Fig. 2, the second recess 22 has two second inner sides 22b facing each other in the width direction W, two second bottom surfaces 22a continuing to the lower ends of the second inner sides 22b, and a second top surface 22c connecting the upper ends of the second inner sides 22b.

[0023] The second inner surface 22b extends along both the up-down 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. In other words, the second bottom surface 22a and the second top surface 22c extend perpendicular to the up-down direction Z.

[0024] 2, both ends of the second recess 22 in the width direction W are located outward from both ends of the first recess 21 in the width direction W. The first recess 21 is open 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> 1 to 3, the damper 30 is a cylindrical metal member and is housed in the second recess 22. The damper 30 of this embodiment is made of steel.

[0026] As shown in Fig. 3, the damper 30 of this embodiment has a rectangular cylindrical 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, respectively, 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. In this embodiment, the lower wall 30a, the two side walls 30b, and the upper wall 30c are all square plate-shaped.

[0027] The damper 30 is configured to be immovable in the vertical direction Z by abutting against 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 FIG. 3).

[0028] The damper 30 is fixed to the anchor bolt 11 by nuts 40. The two nuts 40 sandwich the damper 30 therebetween. The foundation 10, anchor bolt 11, and column 20 in this embodiment correspond to the first material, bolt, and second material in the "Means for solving the problem" section, respectively.

[0029] <Operation of this embodiment> As shown in Figure 2, a cylindrical metallic 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 into an insertion hole 23 of the column 20 and passes through a through-hole 31 of the damper 30, and is fixed to the damper 30 by a nut 40. Therefore, when an earthquake causes a force that tries to tilt the column 20 relative to the foundation 10, that is, a force that tries to move the column 20 away from the foundation 10, the force is transmitted to the lower wall 30a, which is the portion of the damper 30 adjacent to the first recess 21.

[0030] 4, the damper 30 serves 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 that it bulges toward the first recess 21. In other words, the force is consumed in deforming the damper 30 itself, which prevents the damper 30 from sinking into the second bottom surface 22a of the wooden pillar 20 and destroying the pillar 20.

[0031] <Relationship between column deformation angle and horizontal force in Examples and Comparative Examples> Next, with reference to FIG. 5, 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 a force tending to tilt the column, will be described.

[0032] In Fig. 5, the solid line indicates the measurement results for the earthquake-resistant structure of the wooden building of the example, and the two-dot chain line indicates the measurement results for the earthquake-resistant structure of the wooden building of the comparative example. The earthquake-resistant structure of the wooden building of the comparative example is a structure using washer 130 shown in Fig. 6.

[0033] The cross section of the pillar 20 in this embodiment is a square with sides of 300 mm. The length of the pillar 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 pillar 120 of the comparative example is a square with sides of 300 mm. The length of the pillar 120 is 6000 mm. The washer 130 is a square with sides of 75 mm. The thickness of the washer 130 is 3.2 mm.

[0035] As shown by the two-dot chain 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 rapidly as the deformation angle θ increases. In the region where the deformation angle θ is from 0.015 to 0.024, the horizontal force p decreases rapidly as the deformation angle θ increases. Furthermore, in the region where the deformation angle θ is greater than 0.024, the horizontal force p decreases gradually as the deformation angle θ increases.

[0036] In the region where the deformation angle θ is from 0.015 to 0.024, it is thought that the force tending to tilt the column 120 caused the washer 130 to sink into the bottom surface of the hole 122, and the destruction of the column 120 progressed, causing the horizontal force p to decrease rapidly as the deformation angle θ increased.

[0037] As shown by the solid line in Figure 5, in the Example, the horizontal force p increases as the deformation angle θ increases in the region where the deformation angle θ is 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 that of the Comparative Example, but in the region where the deformation angle θ is 0.024 or more, the horizontal force p is larger than that of the Comparative Example.

[0038] In the region where the deformation angle θ is from 0 to 0.06, it is thought that the horizontal force p increased as the deformation angle θ increased because the lower wall 30a of the damper 30 bulged toward the first recess 21 due to the force tending to tilt the pillar 20.

[0039] <Effects of this embodiment> (1) The earthquake-resistant structure of a wooden building includes a foundation 10, an anchor bolt 11, a wooden pillar 20, and a cylindrical metal damper 30. The pillar 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 outward from both ends of the first recess 21 in the width direction W. The damper 30 is housed in the second recess 22 and abuts against the second recess 22, making it immovable in the extension direction of the pillar 20. The damper 30 has a through hole 31 through which the anchor bolt 11 passes, and is fixed to the anchor bolt 11 with a nut 40.

[0040] This configuration achieves the effects of the above-described embodiment, and makes it possible to increase the restoring force of the column 20 against forces tending to tilt the column 20 in the large deformation angle range compared to when a conventional general washer 130 is used.

[0041] (2) The first recess 21 has a rectangular parallelepiped storage space formed between two first inner surfaces 21b extending along the extension direction of the pillar 20. The second recess 22 has a rectangular parallelepiped storage space formed between two second inner surfaces 22b extending along the extension direction of the pillar 20. The damper 30 has a rectangular tubular shape.

[0042] According to this configuration, the damper 30 has a rectangular cylindrical shape, which simplifies the shape of the damper 30. Therefore, the damper 30 can be easily formed. <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0043] The number of anchor bolts 11 provided in one pillar 20 is not limited to two. For example, if four anchor bolts 11 are provided, four sets of insertion holes 23, first recesses 21, and second recesses 22 may be provided corresponding to the number of anchor bolts 11. In this case, the anchor bolts 11 are preferably provided at 90-degree intervals around the central axis of the pillar 20. Furthermore, if the pillar 20 is thin, one anchor bolt 11 may be provided so as to pass through the central axis of the pillar 20.

[0044] The shape of the damper 30 is not limited to a rectangular tubular shape. For example, if the second recess 22 has a cylindrical storage space extending along the depth direction D, the damper 30 may be cylindrical.

[0045] In the above embodiment, the first member, bolt, and second member are respectively embodied as the foundation 10, anchor bolt 11, and column 20, but the present invention is not limited to this. Alternatively, for example, the first member may be a cross member and the second member may be a column extending upward from the cross member.

[0046] As shown in FIG. 7 , the first member may be a wooden pillar 210, and the second member may be a wooden cross member 220 extending laterally from the pillar 210. In this case, a bolt 211 protrudes laterally from the pillar 210. The cross member 220 extends along the bolt 211 and is fixed to the pillar 210 via the bolt 211. The cross member 220 is provided with a first recess 221, a second recess 222, and an insertion hole 223. The damper 30 is accommodated in the second recess 222 and abuts against the second recess 222, making it immovable in the extension direction of the cross member 220, i.e., the horizontal direction. Note that the damper 30 has the same configuration as in the above embodiment, and therefore will not be described here. [Explanation of symbols]

[0047] 10…Basics 11,111...Anchor bolt 20,120...pillar 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...Nut 122...hole 130...Washer 210...pillar 211...Bolt 220...beam 221...First recess 222...Second recess 223...Through hole

Claims

1. a first member that is one of a foundation, a wooden column, and a wooden cross member; a bolt protruding upward or laterally from the first member; A second member is either a wooden pillar or a wooden cross member, and extends along the bolt and is fixed to the first member via the bolt; A metal cylindrical damper is provided. 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 to a side surface and communicates with a tip of the insertion hole; a second recess located on the opposite side of the insertion hole with the first recess in the extending direction of the second material, the second recess opening to the side surface and communicating with the first recess, both ends of the second recess in the width direction of the side surface are located outside both ends of the first recess in the width direction, The damper is accommodated in the second recess and abuts against the second recess so as to be immovable in the extension direction of the second material, has a through hole through which the bolt passes, and is fixed to the bolt by a nut. Earthquake-resistant structure of wooden buildings.

2. the first recess has a rectangular parallelepiped accommodation space formed between two first inner surfaces extending along an extension direction of the second material, the second recess has a rectangular parallelepiped accommodation space formed between two second inner surfaces extending along the extension direction of the second material, The damper is a square tube. The earthquake-resistant structure of a wooden building according to claim 1.

3. The first material is a foundation, The bolt is an anchor bolt protruding upward from the first material, the second member is a pillar, The first recess and the second recess are provided in the base portion of the second material.

3. An earthquake-resistant structure for a wooden building according to claim 1 or 2.

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