JP7669097B2 - Joint structure of wooden members - Google Patents

Description

The present invention relates to a joint structure for wooden members used in buildings.

In recent years, following the revision of the Building Standards Act in 2000, restrictions on height and size were relaxed for wooden buildings that met certain standards and performance standards, making it possible to build taller wooden buildings. Following the trend toward taller wooden buildings, it has become possible to build mid- to high-rise wooden buildings of three stories or more even on sites with narrow frontage.
On the other hand, the number of wooden public facilities is increasing following the enforcement of the Law for Promoting the Use of Wood in Public Buildings in 2010. The wooden construction rate for public buildings that began construction in fiscal 2014 exceeded 10%, and it is expected that the number of public facilities using wood will increase in the future.
In mid- to high-rise wooden buildings with three or more floors, there is a prior art that uses structural steel columns as the main structural members and wooden structural beams (main beams) as the cross members, and uses beam support metal fittings at the joints between the structural columns and the wooden structural beams to improve the rigidity and durability of the building. Restrictions on the height and size of wooden buildings have been relaxed if certain standards are met, so there is an increasing trend for medium to large wooden buildings.

Traditionally, when joining wooden components such as columns and beams in wooden buildings, steel plate insertion drift pin joints and GIR (Glued in Rod) joints are used.

A steel plate insertion type drift pin joint is a joining method in which a steel plate is inserted into a wooden member, and drift pins are inserted into holes drilled in the wooden member and the steel plate to sew the two members together. This joining method is currently one of the most frequently used techniques for wooden rigid frames, and has very stable yield behavior up to the end of the load, but if the wooden member splits before the drift pin at the end of the load, the yield behavior becomes unstable (see non-patent document 1).

On the other hand, GIR joints are a method of joining wooden components by inserting metal fittings (steel rods) into holes drilled in advance in the wooden components and then applying adhesive to join the components together. This joining method is often used in small houses and the like, and each metal fitting can withstand a high tensile force. In addition, since the joints are not visible, it is also superior in terms of design and fire resistance (see non-patent document 2).

"Guide to the development and design of joints in wooden houses using Hokkaido timber" by the Hokkaido Research Organization, a local independent administrative institution "Connectors / Glue-In Rods (GIR)" with explanations of connectors and components (http://media.toriaez.jp/b0409/118283611265.pdf)

However, the former type of steel plate insertion drift pin joint has low rigidity because resistance to external forces is provided by the bending rigidity of the drift pin and the embedding rigidity of the wood, and so is subject to large deformation when subjected to external forces. In addition, because the wood embeds itself in the joint, if the component is significantly deformed, the wood will be damaged and difficult to repair.

On the other hand, with the latter GIR joint, the elements that resist external forces are the axial rigidity of the metal (adhesive) and the embedding rigidity of the wood, and in many cases the surrounding wood breaks before the metal, making it prone to very unstable fracture behavior. Furthermore, when multiple metals are used in one joint, there are problems such as the tendency for the forces borne by each metal to vary, and the difficulty of improving construction precision. Another problem is that if large deformation occurs in the components, the wood will break, making repairs difficult.

The present invention was made to solve the above problems, and aims to provide a joint structure for wooden members that can suppress deformation due to external forces such as earthquake loads and wind loads, has stable ultimate yield behavior, and is easy to repair after a disaster.

In order to achieve the above-mentioned object, the present invention is a joint structure for wooden members used in buildings, characterized in that it comprises a pair of first steel plates arranged to sandwich a joint of a first wooden member, a first fastening member that penetrates the joint of the first wooden member and the first steel plate to fix the pair of first steel plates to the first wooden member, a pair of second steel plates arranged to sandwich a joint of a second wooden member, a second fastening member that penetrates the joint of the second wooden member and the second steel plate to fix the pair of second steel plates to the second wooden member, and a connecting member that connects the first steel plate and the second steel plate.

The joining structure of wooden members according to the present invention described above may also include elastic members provided between the first fastening member and the first steel plate, and between the second fastening member and the second steel plate.

In the above-mentioned joint structure for wooden members according to the present invention, the elastic member may be a disc spring.

In the joining structure of wooden members according to the present invention described above, the connecting member may be joined to the first steel plate and the second steel plate.

The above-mentioned joint structure for wooden members according to the present invention may further include an insert member provided on the joint surfaces of the first wooden member and the second wooden member.

In the joint structure of wooden members according to the present invention described above, both the first wooden member and the second wooden member may be pillars.

In the joint structure of wooden members according to the present invention described above, the first wooden member may be a pillar, and the second wooden member may be a beam.

The present invention provides a variety of excellent effects, such as suppressing deformation caused by external forces such as earthquake loads and wind loads.

1 is a front view showing a joint structure for wooden members according to a first embodiment of the present invention; 1 is a side view showing a joint structure for wooden members according to a first embodiment of the present invention; FIG. 6 is a front view showing a joint structure for wooden components according to a second embodiment of the present invention. FIG. 6 is a plan view showing a joint structure for wooden members according to a second embodiment of the present invention.

The joining structure of wooden members according to an embodiment of the present invention will be described below with reference to the attached drawings.

[First embodiment]
First, a joint structure 10 for wooden members according to a first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a front view of the joint structure 10 for wooden members according to the first embodiment of the present invention, and Figure 2 is a side view of the joint structure 10 for wooden members according to the first embodiment of the present invention. For convenience, in the following description, the front side of the paper in Figure 1 is taken as the front side, and the left and right directions are described based on the direction as seen from the front.

The joining structure 10 for wooden members according to the first embodiment of the present invention relates to a structure for joining an upper column 11 as a first wooden member and a lower column 12 as a second wooden member. Note that Figs. 1 and 2 show an example of joining upper and lower columns 11, 12 each having a cross-sectional dimension of 600 mm x 600 mm.

The joint 13 at the lower end of the upper column 11 has notches 14a, 14b formed on the front and back sides, respectively. A pair of first steel plates 15a, 15b fit into these notches 14a, 14b so as to sandwich the joint 13. Note that the first steel plates 15a, 15b can be fixed to the joint 13 without forming the notches 14a, 14b in the joint 13 at the lower end of the upper column 11, but by forming the notches 14a, 14b in the column 11 where the first steel plates 15a, 15b fit, as shown in Figures 1 and 2, the construction of the fire-resistant coating can be made easier and the design can be improved.

The first steel plates 15a, 15b are rectangular with front dimensions of, for example, 600 mm x 600 mm and have a thickness of 22 mm. The first steel plates 15a, 15b have a plurality of (17 in the figure) circular holes 16a, 16b formed at equal intervals at corresponding positions. The circular holes 16a, 16b do not necessarily have to be formed at equal intervals. In addition, the lower ends of the first steel plates 15a, 15b have notches 17 (only the front side is shown) formed at one each on the left and right. The notches 17 are formed by vertical portions 18 extending upward from the lower ends of the first steel plates 15a, 15b in a front view, and widening portions 19 extending left and right at the upper ends of the vertical portions 18.

The pair of first steel plates 15a, 15b are fixed to the joint 13 by a plurality of (17 in the figure) first fastening members 20 that penetrate the round holes 16a, 16b and the joint 13 of the upper column 11 horizontally from the front side to the back side. The first fastening members 20 are composed of, for example, an M24 bolt 21, a nut 22 that screws into the tip of the bolt 21, and a coned disc spring 23 as an elastic member. The coned disc spring 23 has an outer diameter of, for example, 50 mm, and is interposed between the head of the bolt 21 and the first steel plate 15a on the front side. Note that the coned disc spring 23 may be interposed in a stack of multiple sheets, or may be interposed between the nut 22 and the first steel plate 15b on the back side. Also, instead of providing the first fastening members 20, it may be configured to apply prestress between the first steel plates 15a and 15b.

The joint 24 at the upper end of the lower column 12 has notches 25a, 25b formed on the front and back sides, respectively. A pair of second steel plates 26a, 26b fit into these notches 25a, 25b so as to sandwich the joint 24. Note that the second steel plates 26a, 26b can be fixed to the joint 24 without forming the notches 25a, 25b in the joint 24 at the lower end of the lower column 12, but by forming the notches 25a, 25b in the column 12 where the second steel plates 26a, 26b fit, as shown in Figures 1 and 2, the construction of the fire-resistant coating can be made easier and the design can be improved.

The second steel plates 26a, 26b are rectangular with front dimensions of, for example, 600 mm x 600 mm and have a thickness of 22 mm. The second steel plates 26a, 26b have a plurality of (17 in the figure) round holes 27a, 27b formed at equal intervals at corresponding positions. The plurality of round holes 27a, 27b do not necessarily have to be formed at equal intervals. The second steel plates 26a, 26b do not necessarily have to have the same shape as the first steel plates 15a, 15b. The upper ends of the second steel plates 26a, 26b have notches 28 (only the front side is shown) formed below the notches 17 of the first steel plates 15a, 15b, one on each side. When viewed from the front, the notch 28 is formed by a vertical portion 29 that extends downward from the upper end of the second steel plate 26a, 26b, and a widened portion 30 that extends left and right at the lower end of the vertical portion 29, and has a shape that is the upside-down shape of the notch 17 of the first steel plate 15a, 15b.

The pair of second steel plates 26a, 26b are fixed to the joint 24 by a plurality of (17 in the figure) second fastening members 31 that penetrate the round holes 27a, 27b and the joint 24 of the lower column 12 horizontally from the front side to the back side. The second fastening members 31 are configured to include a bolt 32, a nut 33, and a coned disc spring 34 as an elastic member, similar to the first fastening members 20. The coned disc spring 34 has an outer diameter of, for example, 50 mm, and is interposed between the head of the bolt 32 and the second steel plate 26a on the front side. Note that the coned disc spring 34 may be interposed in a stack of multiple sheets, or may be interposed between the nut 33 and the second steel plate 26b on the back side. Also, instead of providing the second fastening members 31, it may be configured to apply prestress between the second steel plates 26a and 26b.

By fixing the first steel plates 15a, 15b and the second steel plates 26a, 26b to the joints 13, 24 of the upper and lower columns 11, 12, respectively, the first steel plates 15a, 15b and the second steel plates 26a, 26b are in contact with each other along the joint surfaces of the upper and lower columns 11, 12 on the front and back sides of the columns 11, 12. Therefore, a connecting member 35 is provided between the first steel plates 15a, 15b and the second steel plates 26a, 26b.

The connecting member 35 is made of steel plate and has a shape that combines the notches 17 of the first steel plates 15a, 15b and the notches 28 of the second steel plates 26a, 26b, and is composed of a straight section 36 that extends vertically, and an upper end widening section 37 and a lower end widening section 38 that extend horizontally at the upper and lower ends of the straight section 36, respectively. Therefore, the connecting member 35 fits into the space formed by the notches 17 of the first steel plates 15a, 15b and the notches 28 of the second steel plates 26a, 26b, thereby fastening the first steel plates 15a, 15b and the second steel plates 26a, 26b.

In addition, an insert member 39 is inserted and glued into the joint surfaces of the upper pillar 11 and the lower pillar 12. The insert member 39 is, for example, a GIR (Glued in Rod) with an outer diameter of 24 mm, and multiple pieces (for example, five pieces) are provided on each side. Note that the insert member 39 may be a material other than a GIR, such as a wooden dowel.

According to the joint structure 10 for wooden members according to the first embodiment described above, the joints of the columns 11, 12 utilize the frictional forces between the columns 11, 12 and the first steel plates 15a, 15b and the second steel plates 26a, 26b, so that horizontal deformation due to external forces such as earthquake loads and wind loads can be suppressed, particularly when constructing medium- to large-scale wooden buildings. This also makes it possible to reduce the number of horizontal force resistance members such as braces, which reduces costs and provides design benefits. Furthermore, since the wood will not be damaged unless a force greater than the maximum static friction force is generated, it is also possible to easily repair the building after a disaster. In addition, since only the steel material is damaged, the yield behavior of the joints is stable.

In addition, since the first fastening member 20 and the second fastening member 31 are equipped with elastic members (e.g., disc springs 23, 34), even if the pillars 11, 12 expand and contract due to changes in the surrounding humidity, the action of the elastic members keeps the steel plate and the wood in constant pressure contact, and can follow the changes in the cross-sectional dimensions of the pillars 11, 12, thereby suppressing the reduction in the above-mentioned frictional force due to changes in the cross-sectional dimensions of the pillars 11, 12.

Furthermore, because the steel plates are divided into the first steel plates 15a, 15b and the second steel plates 26a, 26b for each of the columns 11, 12 to be joined, it is possible to deal with cases in which the cross-sectional deformation of the columns 11, 12 to be joined is uneven, and the reduction in the above-mentioned frictional force can be suppressed.

In addition, by inserting the insert members 39 into the joint surfaces of the columns 11 and 12, the insert members 39 can bear the shear force that occurs at the joints of the columns 11 and 12.

In the joint structure 10 for wooden members according to the first embodiment described above, the first steel plates 15a, 15b and the second steel plates 26a, 26b are attached only to the two faces, the front and back sides, of the upper and lower columns 11, 12, but these steel plates 15a, 15b, 26a, 26b can also be attached to the left and right sides of the upper and lower columns 11, 12 in a similar manner. By attaching the steel plates 15a, 15b, 26a, 26b to the four faces of the upper and lower columns 11, 12 in this way, the frictional force is further strengthened, and the effect of suppressing horizontal deformation due to external forces such as earthquake loads and wind loads can be further improved.

Second Embodiment
Next, a joint structure 40 for wooden members according to a second embodiment of the present invention will be described with reference to Figures 3 and 4. Figure 3 is a front view of the joint structure 40 for wooden members according to the second embodiment of the present invention, and Figure 4 is a plan view of the joint structure 40 for wooden members according to the second embodiment of the present invention. In the following description, for convenience, the front side of the paper in Figure 3 is the front side, and the left and right directions are described based on the direction seen from the front. In addition, in the following description, detailed description of the same configuration and operation as those of the joint structure 10 for wooden members according to the first embodiment described above will be omitted.

The joining structure 40 for wooden members according to the second embodiment of the present invention relates to a structure for joining a beam 42 as a second wooden member horizontally to the side of a column 41 as a first wooden member. Note that Figures 3 and 4 show an example of joining a column 41 and a beam 42 each having a cross-sectional dimension of 600 mm x 600 mm.

The joint 43 of the column 41 has notches 44a and 44b formed on the front and back sides, respectively. A pair of first steel plates 45a and 45b are fitted into these notches 44a and 44b so as to sandwich the joint 43. A plurality of round holes 46a and 46b are formed at equal intervals in the first steel plates 45a and 45b at corresponding positions. The plurality of round holes 46a and 46b do not necessarily have to be formed at equal intervals. In addition, notches 47 (only the front side is shown) are formed at the right ends of the first steel plates 45a and 45b, one each at the top and bottom. The notches 47 are formed by a horizontal portion 48 extending leftward from the right ends of the first steel plates 45a and 45b in a front view, and a widening portion 49 extending up and down at the left end of the horizontal portion 48.

The pair of first steel plates 45a, 45b are fixed to the joint 43 by a plurality of first fastening members 50 that penetrate the round holes 46a, 46b and the joint 43 of the column 41 horizontally from the front side to the back side. The first fastening members 50 are configured to include a bolt 51, a nut 52, and a coned disc spring 53 as an elastic member. The coned disc spring 53 is interposed between the head of the bolt 51 and the first steel plate 45a on the front side. Note that the coned disc spring 53 may be interposed in a stack of multiple sheets, or may be interposed between the nut 52 and the first steel plate 45b on the back side. Also, instead of providing the first fastening members 50, it may be configured to apply prestress between the first steel plates 45a and 45b.

At the joint 54 at the left end of the beam 42, notches 55a and 55b are formed on the front side and the back side, respectively. A pair of second steel plates 56a and 56b are fitted into these notches 55a and 55b so as to sandwich the joint 54. The second steel plates 56a and 56b have the same shape as the first steel plates 45a and 45b. The second steel plates 56a and 56b have a plurality of round holes 57a and 57b formed at equal intervals at corresponding positions. Note that the plurality of round holes 57a and 57b do not necessarily have to be formed at equal intervals. In addition, at the left end of the second steel plates 56a and 56b, one notch 58 (only the front side is shown) is formed at the top and bottom, respectively, to the right of the notch 47 of the first steel plates 45a and 45b. When viewed from the front, the notch 58 is formed by a horizontal portion 59 that extends to the right from the left end of the second steel plates 56a and 56b, and a widened portion 60 that extends up and down at the right end of the horizontal portion 59, and has a shape that is the left-right inversion of the notch 47 of the first steel plates 45a and 45b.

The pair of second steel plates 56a, 56b are fixed to the joint 54 by a plurality of second fastening members 61 that horizontally penetrate the round holes 57a, 57b and the joint 54 of the beam 42 from the front side to the back side. The second fastening member 61 is configured to include a bolt 62, a nut 63, and a coned disc spring 64 as an elastic member, similar to the first fastening member 50. The coned disc spring 64 is interposed between the head of the bolt 62 and the second steel plate 56a on the front side. Note that the coned disc spring 64 may be interposed in a stack of multiple sheets, or may be interposed between the nut 63 and the second steel plate 56b on the back side. Also, instead of providing the second fastening member 61, it may be configured to apply prestress between the second steel plates 56a and 56b.

By fixing the first steel plates 45a, 45b and the second steel plates 56a, 56b to the joints 43, 54 of the column 41 and the beam 42, respectively, the first steel plates 45a, 45b and the second steel plates 56a, 56b are in contact with each other on the front and back sides of the column 41 and the beam 42 along the joint surfaces of the column 41 and the beam 42. Therefore, a connecting member 65 is provided between the first steel plates 45a, 45b and the second steel plates 56a, 56b.

The connecting member 65 is made of steel plate and has a shape that combines the notches 47 of the first steel plates 45a, 45b and the notches 58 of the second steel plates 56a, 56b, and is composed of a straight portion 66 extending left and right, and a left end widening portion 67 and a right end widening portion 68 that extend up and down at the left and right ends of the straight portion 66, respectively. Therefore, the connecting member 65 fits into the space formed by the notches 47 of the first steel plates 45a, 45b and the notches 58 of the second steel plates 56a, 56b, thereby fastening the first steel plates 45a, 45b and the second steel plates 56a, 56b.

In addition, insert members 69 are inserted and glued into the joint surfaces of the columns 41 and beams 42. The insert members 69 are made of GIR (Glued in Rod), and multiple pieces are provided on both the front and back sides. Note that the insert members 69 may be materials other than GIR, such as wooden dowels.

According to the joint structure 40 of wooden members according to the second embodiment described above, the joint between the column 41 and the beam 42 utilizes the frictional force between the column 41 and the beam 42 and the first steel plates 45a, 45b and the second steel plates 56a, 56b, so that it is possible to suppress horizontal deformation due to external forces such as earthquake loads and wind loads, particularly when constructing medium- to large-scale wooden buildings. This also makes it possible to reduce horizontal force resistance members such as braces, which reduces costs and provides design benefits. Furthermore, since the wood is not damaged unless a force greater than the maximum static friction force is generated, it is also possible to easily repair the building after a disaster. In addition, since only the steel material is damaged, the yield behavior of the joint is stable.

In addition, since the first fastening member 50 and the second fastening member 61 are equipped with elastic members (e.g., disc springs 53, 64), even if the pillars 41 and beams 42 expand and contract due to changes in the surrounding humidity, the action of the elastic members keeps the steel plate and the wood in constant pressure contact, and can follow the changes in the cross-sectional dimensions of the pillars 41 and beams 42, thereby suppressing the reduction in the above-mentioned frictional force due to changes in the cross-sectional dimensions of the pillars 41 and beams 42.

Furthermore, because the steel plates are divided into first steel plates 45a, 45b and second steel plates 56a, 56b for each joining column 41 and beam 42, it is possible to deal with cases in which the cross-sectional deformation of the joining column 41 and beam 42 is non-uniform, and the reduction in the above-mentioned frictional force can be suppressed.

Furthermore, by inserting the insert members 69 into the joint surfaces of the column 41 and the beam 42, even if a force greater than the maximum static friction force is generated at the joint between the column 41 and the beam 42, the subsequent behavior can be made relatively stable until the end.

In the wooden member joint structures 10, 40 according to the first and second embodiments described above, the disc springs 23, 64 are used as the elastic members, but the elastic members may be coil springs, leaf springs, rubber, or a combination of these, in addition to disc springs.

In addition, in the joint structures 10, 40 of wooden members according to the first and second embodiments described above, the connecting members 35, 65 are fitted into the spaces formed by the notches 17, 47 of the first steel plates 15a, 15b, 45a, 45b and the notches 28, 58 of the second steel plates 26a, 26b, 56a, 56b, so that the first steel plates 15a, 15b, 45a, 45b and the second steel plates 26a, 26b, 56a, 56b are connected to each other. Although the structure in which the first steel plates 15a, 15b, 45a, 45b and the second steel plates 26a, 26b, 56a, 56b are fastened has been described, the first steel plate and the second steel plate can also be connected by other connecting means, such as by providing a connecting member (e.g., a steel plate) between the first steel plate 15a, 15b, 45a, 45b and the second steel plate 26a, 26b, 56a, 56b, and fastening the connecting member to the first steel plate and the second steel plate, respectively, with fasteners such as bolts.

In addition, in the first and second embodiments of the joining structures 10 and 40 for wooden members described above, the cases of joining columns 11 and 12 to each other and joining a column 41 to a beam 42 have been described, but this is merely an example, and the present invention can also be applied to cases of joining beams to each other, for example.

The present invention may be modified as appropriate within the scope of the claims and the overall specification without violating the spirit or concept of the invention, and the joint structure of wooden members that involves such modifications is also included in the technical concept of the present invention.

10 Joint structure of wooden members 11 Upper pillar (first wooden member)
12 Lower pillar (second wooden member)
13 Joint portion 15a, 15b First steel plate 20 First fastening member 23 Disc spring (elastic member)
24 Joint portion 26a, 26b Second steel plate 31 Second fastening member 34 Disc spring (elastic member)
35 Connection member 39 Insert member 40 Joint structure of wooden members 41 Pillar (first wooden member)
42 Beam (second wooden member)
43 Joint portion 45a, 45b First steel plate 50 First fastening member 53 Disc spring (elastic member)
54 Joint portion 56a, 56b Second steel plate 61 Second fastening member 64 Disc spring (elastic member)
65 Connection member 69 Insertion member

Claims (7)

A joint structure for wooden members used to join a joint portion of a first wooden member and a joint portion of a second wooden member ,
a pair of first steel plates arranged to sandwich the joint of the first wooden member so as to generate a frictional force between the first steel plates and the joint of the first wooden member;
a first fastening member that penetrates the joint of the first wooden member and the first steel plate to fix the pair of first steel plates to the joint of the first wooden member;
a pair of second steel plates provided to sandwich the joint of the second wooden member so as to generate a frictional force between the second steel plates and the joint of the second wooden member;
a second fastening member that penetrates the joint of the second wooden member and the second steel plate to fix the pair of second steel plates to the joint of the second wooden member;
A connection member provided across the first steel plate and the second steel plate;
wherein the first steel plate and the second steel plate are fastened by the connecting member in a state in which the first steel plate and the second steel plate are in contact with each other along a joint surface between the joint of the first wooden member and the joint of the second wooden member. The joining structure of wooden members according to claim 1, further comprising elastic members provided between the first fastening member and the first steel plate and between the second fastening member and the second steel plate. The joining structure for wooden members according to claim 2, wherein the elastic member is a disc spring. A joining structure for wooden members according to any one of claims 1 to 3, in which the connecting member is joined to the first steel plate and the second steel plate. The joining structure for wooden members according to any one of claims 1 to 4, further comprising an insert member provided on the joining surfaces of the first wooden member and the second wooden member. The joining structure of wooden members according to any one of claims 1 to 5, wherein the first wooden member and the second wooden member are both pillars. The joint structure for wooden members according to any one of claims 1 to 5, wherein the first wooden member is a pillar and the second wooden member is a beam.

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