Joint structure
The joint structure for laminated bamboo lumber uses a plate-shaped protrusion and load transmission part to efficiently transmit tensile loads, addressing the challenge of balancing high tensile strength and securing bearing capacity.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- KAJIMA CORP
- Filing Date
- 2025-01-17
- Publication Date
- 2026-07-30
AI Technical Summary
Bolted joints in laminated bamboo lumber face challenges in securing sufficient bearing capacity that balances its high tensile strength, necessitating inefficient increases in bolt number and size.
A joint structure featuring a plate-shaped protrusion fitted into the bamboo laminated timber, transmitting tensile loads through a load transmission part, such as a steel plate, to enhance bearing capacity.
The joint structure efficiently transmits tensile loads, ensuring balanced bearing capacity by increasing the bearing area of the protrusion, simplifying the configuration, and securely holding the protrusion in place.
Smart Images
Figure 2026123607000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a joint structure at the end of laminated bamboo lumber.
Background Art
[0002] Laminated bamboo lumber is manufactured by integrating members cut from bamboo with an adhesive or the like. In recent years, laminated bamboo lumber has begun to attract attention mainly overseas as a sustainable, low-carbon and high-strength natural material, and its use as a structural body has been progressing.
[0003] When using laminated bamboo lumber as a structural body, it is basically necessary to follow the construction method for wooden materials. For joining laminated bamboo lumber, bolt joining is generally used in the same way as for joining wooden materials. This involves inserting a steel plate extending from the joining target into a slit of the laminated bamboo lumber, using bolts that penetrate the laminated bamboo lumber and the steel plate, and fastening the laminated bamboo lumber on both sides of the steel plate.
[0004] In addition, Patent Document 1 discloses that a plate-like consolidated body formed of bamboo is disposed on both side surfaces of a pair of wooden materials so as to straddle the opposing ends of the wooden materials, and bolts that penetrate the ends of the respective wooden materials and the consolidated bodies on both side surfaces thereof are used to fasten the consolidated bodies on both side surfaces of the respective wooden materials, thereby joining the pair of wooden materials. Conical claw portions are provided on the surface of the consolidated body on the wooden material side, and when the consolidated body is disposed on both side surfaces of the wooden material, the claw portions bite into the wooden material.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] In bolted joints of wood materials, the tensile load from the joint is transmitted from the steel plate to the bolt, and then further transmitted from the bolt to the wood material by the bearing pressure of the bolt shaft. In this case, in order to prevent the bolted joint from yielding before the general part of the wood material (the part other than the bolted joint), the bearing capacity of the bolt must be greater than the tensile strength of the wood material.
[0007] Bamboo laminated timber has extremely high tensile strength compared to ordinary wood, and if the joint described above is designed in the same way as for ordinary wood, it is difficult to secure bearing capacity that balances the tensile strength. In other words, in order to secure sufficient bearing capacity, it is necessary to drastically increase the number of bolts and enlarge the bearing area of the bolt shafts, which is inefficient.
[0008] This invention has been made in view of the above problems, and aims to provide a joint structure, etc., that can easily secure bearing capacity that balances the high tensile strength of laminated bamboo timber. [Means for solving the problem]
[0009] The present invention, which solves the above problems, is a joint structure for the end of a bamboo laminated timber, characterized by having a plate-shaped protrusion that is held in a state of being fitted into the bamboo laminated timber, and a load transmission part that transmits a tensile load from the end of the bamboo laminated timber to the protrusion.
[0010] According to the above-described joint structure, the tensile load from the object to be joined is transmitted to the protrusion by a load-transmitting part such as a steel plate, and this tensile load is further transmitted from the protrusion to the bamboo laminated timber by the bearing pressure of the protrusion. In this invention, by fitting a plate-shaped protrusion into the bamboo laminated timber, the bearing area of the protrusion can be increased. As a result, the tensile load can be efficiently transmitted between the protrusion and the bamboo laminated timber, and a bearing capacity that balances the high tensile strength of the bamboo laminated timber can be easily secured.
[0011] Preferably, the load transmission portion is a steel plate extending from the object to be joined, and the protrusion is provided on the side of the steel plate facing the bamboo laminated material. By providing the protrusions on the steel plate extending from the object to be joined, the configuration of the joining structure becomes simpler, and the steel plate, which is the load-transmitting part, and the protrusions can be manufactured as a single integrated component.
[0012] The steel plates are arranged, for example, on both sides of the bamboo laminated timber, and the steel plates on both sides of the bamboo laminated timber are fastened together using bolts and nuts. Alternatively, the steel plates may be arranged to cover the entire circumference of the cross-section of the bamboo laminated timber. By fastening steel plates on both sides of the bamboo laminated timber using bolts and nuts, or by placing steel plates around the entire circumference of the bamboo laminated timber, the protruding portion can be securely held in place while embedded in the bamboo laminated timber.
[0013] Steel plates are arranged on both sides of the bamboo laminated timber, the protrusions are provided on the bamboo laminated timber-facing surfaces of both steel plates, the steel plates arranged on both sides of the bamboo laminated timber are fastened together using bolts and nuts that penetrate the bamboo laminated timber, and the load transmission portion includes the bolts and an inserting member that extends from the objects to be joined and is inserted into the interior of the bamboo laminated timber, and it is also desirable that the bolts pass through the inserting member. In this case, a bolt and nut are used to securely hold the protrusion in place within the bamboo laminated timber. Furthermore, by passing the bolt through the insert, the load transmission section, including the bolt and insert, can transmit tensile load from the joined object to the protrusion. Additionally, when a tensile load is applied to the insert, a force is applied to the steel plates on both sides of the bamboo laminated timber in a direction that reduces the distance between the steel plates. As a result, the steel plates restrain the bamboo laminated timber from both sides, increasing its bearing strength.
[0014] It is desirable that recesses for fitting the protrusions are formed in advance in the aforementioned bamboo laminated material. This allows the protruding part to be easily fitted into the bamboo laminated material. [Effects of the Invention]
[0015] The present invention provides a joint structure and the like that can easily ensure bearing capacity that balances the high tensile strength of laminated bamboo timber. [Brief explanation of the drawing]
[0016] [Figure 1] An example in which the ends of the laminated bamboo lumber 2 are joined using the joining structure 1. [Figure 2] A diagram showing the joining structure 1. [Figure 3] A diagram showing the load transmission part 3 and the laminated bamboo lumber 2. [Figure 4] A diagram showing the joining material 8a. [Figure 5] A diagram showing the load transmission part 3a. [Figure 6] A diagram showing the load transmission part 3b. [Figure 7] A diagram showing the load transmission part 3c. [Figure 8] A diagram showing the joining structure 10. [Figure 9] A diagram showing the insertion piece 40, the load transmission part 30, and the laminated bamboo lumber 20. [Figure 10] A diagram showing the joining structure 100. [Figure 11] A diagram showing the insertion material 300a. [Figure 12] A diagram showing the insertion piece 40a. [Figure 13] A diagram showing the insertion piece 40b. [Figure 14] A diagram showing the joining structure 100a.
Embodiments for Carrying Out the Invention
[0017] Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.
[0018] [First Embodiment] FIG. 1 is a diagram showing an example in which the ends of the laminated bamboo lumber 2 are joined using the joining structure 1 according to the first embodiment of the present invention. The laminated bamboo lumber 2 in FIG. 1 is used as a brace material in a steel frame structure, and the joining target of the ends of the laminated bamboo lumber 2 is a steel joining material 8 fixed to a steel frame beam 9 or a steel frame column by welding or fasteners.
[0019] As mentioned above, bamboo laminated timber 2 is manufactured by laminating pieces cut from bamboo using adhesive or the like. There are no particular restrictions on the shape or size of the pieces cut from the bamboo, or on the adhesive or bonding method used for lamination. Furthermore, laminated timbers that have been secondarily bonded together, or laminated timbers joined together using finger joints, etc., are also included in bamboo laminated timber 2.
[0020] Figure 2 shows the joint structure 1, which is a cross-section of the bamboo laminated timber 2 in the thickness direction along line AA in Figure 1. As shown in Figure 2, the joint structure 1 at the end of the bamboo laminated timber 2 has a load transmission part 3, a protrusion 4, a fastener 5, etc.
[0021] The load transmission section 3 is positioned along each of the opposing sides (referred to as both sides) of the bamboo laminated timber 2 and transmits tensile load from the joining member 8 to the protrusion 4. The load transmission section 3 is a flat steel plate and is provided so as to extend from the joining member 8 towards the bamboo laminated timber 2. In this example, the end of the joining member 8 on the bamboo laminated timber 2 side is branched in a Y shape, and the load transmission sections 3 on both sides of the bamboo laminated timber 2 are joined to each of the branched ends 81 of the joining member 8 by welding or the like. Reference numeral 82 in Figure 2 indicates a reinforcing rib provided between the branched ends 81.
[0022] The protrusion 4 is provided on the bamboo laminated wood 2 side of the load transmission section 3. Figure 3(a) shows the relevant surface of the load transmission section 3. The protrusion 4 is a plate-shaped steel member formed to protrude from the surface, and is provided along the width direction of the load transmission section 3, extending across the entire width of the load transmission section 3.
[0023] Figure 3(b) shows the bamboo laminated timber 2. In this embodiment, the cross-section (hereinafter simply referred to as the cross-section) perpendicular to the longitudinal direction of the bamboo laminated timber 2 is rectangular. Also, recesses 21 for fitting the protrusions 4 are formed on both sides of the bamboo laminated timber 2. The recesses 21 are provided along the width direction of the bamboo laminated timber 2, extending over the entire width of the bamboo laminated timber 2. The width direction of the bamboo laminated timber 2 and the load transmission section 3 refers to the direction perpendicular to the load transmission direction of the tensile load. The load transmission direction corresponds to the left and right directions in Figures 2 and 3(a) and (b).
[0024] As shown in Figure 2, the fastener 5 has a bolt 51 and a nut 52. The bolt 51 is a bolt with a head, and a high-strength bolt can also be used.
[0025] The bamboo laminated timber 2 and the load-transmitting section 3 have pre-formed holes 22 and 31 that penetrate through the thickness direction of each member, and the shaft portion of the bolt 51 is passed through these holes 22 and 31 from one side of the load-transmitting section 3. By tightening a nut 52 onto the tip of the shaft portion protruding from the other load-transmitting section 3, the load-transmitting sections 3 on both sides of the bamboo laminated timber 2 are fastened together, maintaining a constant distance between them, and the protruding portion 4 is held in a state where it is fitted into the recess 21 of the bamboo laminated timber 2.
[0026] Multiple fasteners 5 are arranged at intervals in the width direction and load transmission direction of the bamboo laminated wood 2 (and load transmission section 3). The protrusions 4 are positioned on both sides of the bolt 51 of each fastener 5 in the load transmission direction.
[0027] The joint structure 1 transmits the tensile load acting from the object to be joined (joining material 8) to the protrusion 4 via the load transmission section 3. This tensile load is transmitted to the bamboo laminated timber 2 by the bearing pressure of the protrusion 4. As a result, the bamboo laminated timber 2 can bear and resist the tensile load.
[0028] In the joint structure 10 of this embodiment, the bearing area of the protrusion 4 can be increased by fitting the plate-shaped protrusion 4 into the bamboo laminated timber 2. This allows for efficient transmission of tensile load between the protrusion 4 and the bamboo laminated timber 2, and makes it easy to secure bearing capacity that balances the high tensile strength of the bamboo laminated timber 2. Furthermore, by providing a recess 21 in the bamboo laminated timber 2, the protrusion 4 can be easily fitted into the bamboo laminated timber 2.
[0029] Furthermore, by providing the protrusion 4 on the bamboo laminated wood 2 side of the load transmission part 3, the configuration of the joint structure 1 is simplified, and the load transmission part 3 and the protrusion 4 can be manufactured as a single integrated component. In addition, by fastening the load transmission parts 3 on both sides of the bamboo laminated wood 2 with fasteners 5 consisting of bolts 51 and nuts 52, the state in which the protrusion 4 is fitted into the bamboo laminated wood 2 can be reliably maintained, preventing the protrusion 4 from coming out of the bamboo laminated wood 2 when a tensile load is applied from the jointed object.
[0030] However, this embodiment is not limited to the above-described embodiment. For example, the dimensions and number of protrusions 4 are not limited to those shown in Figure 2, etc., and the design should be such that the total bearing capacity of the protrusions 4 is greater than the tensile strength of the bamboo laminated timber 2. The bearing capacity is determined by the product of the bearing area of the protrusions 4 and the bearing strength of the bamboo laminated timber 2, and if the total bearing area of the protrusions 4 is the same, the bearing capacity will be the same. Therefore, it is possible to increase the bearing area of each protrusion 4 and reduce the number of protrusions 4 installed. In addition, although the load transmission part 3 and the protrusions 4 are made of steel in this embodiment, they may be made of other metal members such as aluminum or titanium alloy.
[0031] In this embodiment, the load transmission section 3 is fastened using a fastener 5 consisting of a bolt 51 and a nut 52. However, instead of the fastener 5, a rod such as a drift pin can be used. In this case, the rod is passed through the holes 22 and 31 of the bamboo laminated wood 2 and the load transmission section 3, and retaining pins are inserted into both ends of the rod that protrude from the load transmission section 3 on both sides of the bamboo laminated wood 2, thereby maintaining the state in which the protrusion 4 is fitted into the bamboo laminated wood 2.
[0032] Furthermore, the shape and configuration of the joining material 8 are not particularly limited. For example, as shown in Figure 4, the joining material 8a may be a pair of steel plates, and each joining material 8a may be fastened to the load-transmitting parts 3 on both sides of the bamboo laminated timber 2 using fasteners 6 consisting of bolts and nuts. Alternatively, the joining material 8 may be omitted, and the load-transmitting parts 3 on both sides of the bamboo laminated timber 2 may be extended, with their ends directly joined to the object to be joined, such as a steel beam 9 or steel column, by welding or fasteners.
[0033] Furthermore, the configuration of the load transmission section 3 is not particularly limited. For example, as shown in Figure 5(a), it is possible to arrange the load transmission section 3a so as to cover the entire circumference of the cross-section of the bamboo laminated timber 2. That is, the load transmission section 3a is a U-shaped member, and a pair of load transmission sections 3a are arranged so as to cover the entire circumference of the rectangular cross-section of the bamboo laminated timber 2.
[0034] As shown in Figure 5(b), the protrusions 4 are provided on the inner surface of the load transmission section 3a (the surface facing the bamboo laminated wood 2). The protrusions 4 are rectangular plate-shaped members, and are fixed to the load transmission section 3a by welding its three sides to the inner surface of the load transmission section 3a. The protrusions 4 on the inner surface of each load transmission section 3a are fitted into the recesses 21 of the bamboo laminated wood 2, and the ends of a pair of load transmission sections 3a are welded together at the welded joint 32, and the load transmission sections 3a are arranged around the entire circumference of the cross-section of the bamboo laminated wood 2, thereby holding the protrusions 4 fitted into the recesses 21.
[0035] Figure 6(a) shows the case where the cross-section of the bamboo laminated timber 2 is circular, in which case the load transmission part 3b is semicircular. As shown in Figure 6(b), the protrusion 4 is a semicircular plate material and is fixed to the inner surface of the load transmission part 3b by welding or the like.
[0036] Figure 7(a) shows the case where the cross-section of the bamboo laminated timber 2 is triangular. In this case, as shown in Figure 7(b), the load-transmitting section 3c is made flat, and three load-transmitting sections 3c are arranged along each of the three sides of the bamboo laminated timber 2. The protrusion 4 is provided in a trapezoidal shape on the bamboo laminated timber 2 side of the load-transmitting section 3c. In this example, instead of welding the load-transmitting sections 3c together, a triangular cylindrical body 33 is fitted onto the outside of the three load-transmitting sections 3c, thereby holding the protrusion 4 in place of the recess 21 of the bamboo laminated timber 2. A similar configuration can be applied when the cross-section of the bamboo laminated timber 2 is a polygon other than a triangle. Furthermore, the method of holding the protrusion 4 using the cylindrical body can be used instead of welding in the examples of Figures 5 and 6, and can be used instead of the fastener 5 in the example of Figure 2.
[0037] In this embodiment, the laminated bamboo timber 2 is used as a bracing member in a steel frame structure, but it is not limited to this. It can also be used as a bracing member in columns and beams of other structural types such as reinforced concrete (RC) or wood. Furthermore, it is applicable when the laminated bamboo timber 2 is used as a axial member other than a bracing member, such as the upper chord, lower chord, or diagonal member of a truss member. The target of the connection at the end of the laminated bamboo timber 2 varies depending on the application of the laminated bamboo timber 2 and is not particularly limited.
[0038] Hereinafter, other examples of the present invention will be described as second and third embodiments. The differences between the second and third embodiments and the embodiments described so far will be explained, and similar components will be denoted by the same reference numerals in the figures, etc., and their descriptions will be omitted. In addition, the components described in each embodiment, including the first embodiment, can be combined as needed.
[0039] [Second Embodiment] Figure 8(a) shows a cross-section of the bamboo laminated timber 20 in the thickness direction for the joint structure 10 according to the second embodiment of the present invention, similar to Figure 2. Figure 8(b) is a top view of the joint structure 10 as seen from the direction indicated by arrow a in Figure 8(a). Figure 8(a) shows a cross-section along line BB in Figure 8(b).
[0040] The joint structure 10 of the second embodiment has a load transmission part 30, an insertion piece 40, a fastener 5, etc., and differs from the first embodiment mainly in that the protrusion 41 that fits into the bamboo laminated wood 20 is separate from the load transmission part 30. That is, in the second embodiment, the protrusion 41 is provided on the insertion piece 40, which is a separate component from the load transmission part 30.
[0041] The load transmission section 30 is a flat steel plate and, similar to the first embodiment, is positioned along each of the two sides of the bamboo laminated timber 20, which has a rectangular cross-section, and transmits tensile load from the joining member 80 to the protrusion 41. The load transmission section 30 is positioned to extend from the joining member 80 towards the bamboo laminated timber 20. In the example shown in Figure 8, the load transmission sections 30 on both sides of the bamboo laminated timber 20 are fastened to the joining member 80 using fasteners 6.
[0042] The insertion piece 40 is a U-shaped component with a steel plate body and protrusions 41 on both sides. The protrusions 41 are provided on the side of the steel plate body facing the bamboo laminated wood 2, and each protrusion 41 fits into a recess 21 in the bamboo laminated wood 20. The protrusions 41 are positioned on both sides of the load transmission direction of the tensile load relative to the bolt 51 of the fastener 5. The load transmission direction corresponds to the left and right directions in Figures 8(a), (b) and Figures 9(a) to (c) described later. The tip of the protrusion 41 on the bamboo laminated wood 20 side is processed to an acute angle, and the tip of the recess 21 has a corresponding shape.
[0043] Figures 9(a) to 9(c) show the insert piece 40, the load transmission section 30, and the bamboo laminated timber 2, respectively. As shown in Figure 9(a), the protrusion 41 is a plate-shaped member extending in the width direction of the insert piece 40. The width direction of the insert piece 40 is perpendicular to the load transmission direction of the tensile load.
[0044] As shown in Figure 9(b), the load transmission section 30 has a slit 34 formed in the width direction of the load transmission section 30 for inserting the protrusion 41 of the insertion piece 40. Also, as shown in Figure 9(c), the width of the end portion 20-1 of the bamboo laminated wood 20 is smaller than that of the general portion (the portion other than the end portion 20-1) 20-2.
[0045] The insertion pieces 40 and load transmission parts 30 have pre-formed holes 42 and 31 that penetrate each member in the thickness direction. As shown in Figure 8(a), the load transmission parts 30 are placed on both sides of the bamboo laminated wood 20, and the insertion pieces 40 are positioned by inserting the protrusions 41 into the slits 34 of each load transmission part 30, so that the protrusions 41 fit into the recesses 21 on both sides of the bamboo laminated wood 20. In this state, the shaft portion of the bolt 51 is passed through the holes 42 and 31 of each insertion piece 40 and each load transmission part 30 from one side of the insertion piece 40, and a nut 52 is tightened on the tip of the shaft portion protruding from the other insertion piece 40. As a result, the insertion pieces 40 on both sides of the bamboo laminated wood 20 are fastened together, their spacing is kept constant, and the protrusions 41 are securely held in place while fitted into the recesses 21 of the bamboo laminated wood 20.
[0046] Furthermore, in this embodiment, as shown in Figure 8(b), the width of the load transmission section 30 and the fitting piece 40 is greater than the width of the end portion 20-1 of the bamboo laminated wood 20, and the shaft portion of the bolt 51 is positioned to avoid the end portion 20-1 of the bamboo laminated wood 20.
[0047] In the joint structure 10 of the second embodiment, the same effect as in the first embodiment can be obtained by fitting the plate-shaped protrusion 41 into the bamboo laminated wood 20. Also, since the bolt 51 passes outside the end portion 20-1 of the bamboo laminated wood 20, a hole 22 for passing the shaft portion of the bolt 51 through the bamboo laminated wood 20 is not required, making it easier to manufacture the bamboo laminated wood 20.
[0048] In this embodiment, the protrusion 41 of the insertion piece 40 is inserted into the recess 21 of the bamboo laminated wood 20. However, the recess 21 may not be formed in the bamboo laminated wood 20, and the protrusion 41 may be directly embedded into the bamboo laminated wood 20. To facilitate the insertion of the protrusion 41, linear notches may be provided in the bamboo laminated wood 20.
[0049] [Third Embodiment] Figure 10(a) shows a cross-section of the bamboo laminated timber 200 in the thickness direction for the joint structure 100 according to the third embodiment of the present invention, similar to Figure 2. Figure 10(b) shows the cross-section of Figure 10(a) along line CC. Figure 10(a) shows the cross-section of Figure 10(b) along line DD.
[0050] The joint structure 100 of the third embodiment includes an inserting member 300, a fitting piece 40, a fastener 5, etc., and differs from the joint structure 1 of the first embodiment in that the inserting member 300 is inserted into the bamboo laminated wood 200.
[0051] The insert material 300 is a flat steel plate and is inserted into a slit 23 provided near the center of the thickness direction at the end of the bamboo laminated wood 200. The insert material 300 is positioned to extend from the joining material 800 towards the bamboo laminated wood 200. In the example shown in Figure 10(a), the insert material 300 is joined to the joining material 800 using fasteners 6.
[0052] The insert pieces 40 are arranged on both sides of the bamboo laminated wood 200, and their protrusions 41 are fitted into recesses 21 provided in the bamboo laminated wood 200, similar to the second embodiment. From one insert piece 40 side, the shaft of the bolt 51 is passed through the holes 42 of each insert piece 40, the holes 22 of the bamboo laminated wood 200, and the holes 310 of the insert material 300, and a nut 52 is tightened onto the tip of the shaft protruding from the other insert piece 40. As a result, the insert pieces 40 on both sides of the bamboo laminated wood 200 are fastened together, maintaining a constant distance between them, and the protrusions 41 are securely held in place while fitted into the recesses 21 of the bamboo laminated wood 200.
[0053] In the third embodiment of the joint structure 100, the tensile load acting from the object to be joined (joining material 800) is transmitted to the protrusion 41 via the insert 300 and bolt 51. This tensile load is transmitted to the bamboo laminated timber 200 by the bearing pressure of the protrusion 41. In other words, in the joint structure 100, the insert 300 and bolt 51 function as load transmission parts that transmit the tensile load from the object to be joined to the protrusion 41.
[0054] In the third embodiment, the same effect as in the first embodiment can be obtained by fitting the protrusion 41 into the bamboo laminated timber 200. Furthermore, in the joint structure 100, when a tensile load is applied to the insert 300 as shown by arrow b, a force is applied to the fitting pieces 40 on both sides of the bamboo laminated timber 200 in a direction that narrows the distance between the fitting pieces 40 as shown by arrow d. As a result, the fitting pieces 40 restrain the bamboo laminated timber 200 from both sides, increasing the bearing strength of the bamboo laminated timber 200. The joint structure 100 is more effective when the cross-section of the bamboo laminated timber 200 is large.
[0055] In this embodiment, the insert member 300 is a flat plate-shaped member, but as shown in Figure 11 with a cross-section similar to that in Figure 10(b), the insert member 300a may be a rod-shaped member. In the example in Figure 11, the cross-section of the insert member 300a perpendicular to the axial direction is circular, and the bolt 51 of the fastener 5 passes through the radial hole 310a of that cross-section. For example, reinforcing bars can be used for the insert member 300a. Alternatively, a wire or other wire may be connected to a cylindrical body such as a pin having a hole 310a.
[0056] As shown in Figure 12, it is also possible to provide a single insert piece 40a for multiple fasteners 5 arranged in the direction of tensile load transmission (corresponding to the left-right direction in Figure 12). In this case as well, the insert piece 40a is provided on both sides of the bamboo laminated wood 200, and protrusions 41 are provided on both sides in the direction of load transmission for each bolt 51 of the fastener 5.
[0057] Alternatively, as shown in Figure 13, the insertion piece 40b may be miniaturized, and insertion pieces 40b may be provided on both sides of the bamboo laminated material 200 for each fastener 5. In this example, the protrusion 41b is a cylindrical plate-like member rather than a flat plate, and the protrusion 41b is provided on one side of the disc-shaped steel plate body 43. The hole 42 for inserting the shaft of the bolt 51 is provided in the steel plate body 43 inside the protrusion 41b. The protrusion 41b may be an elliptical or rectangular cylindrical member, in addition to being cylindrical.
[0058] Furthermore, the joining structure 100 of this embodiment can be used to join bamboo laminated timber 200 to steel beams 9, etc., as in the first embodiment, but the object to be joined is not limited to this, and other bamboo laminated timber 200 may also be used. Figure 14 shows an example of a joining structure 100a for joining bamboo laminated timber 200 together, in which both ends of the inserting member 300 are inserted into the slits 23 at the ends of the bamboo laminated timber 200 to be joined. Other points, such as the inserting piece 40, are the same as in Figure 10. This makes it possible to join bamboo laminated timber 200 together. The joining structure 100a can be applied, for example, to joints between bamboo laminated timber 200, and the length of the bamboo laminated timber 200 can be extended.
[0059] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the technical idea disclosed herein, and these will naturally also fall within the technical scope of the present invention. [Explanation of Symbols]
[0060] 1, 10, 100, 100a: Joint structure 2, 20, 200: Bamboo laminated wood 3, 3a, 3b, 3c, 30: Load transmission part 4, 41, 41b: Convex part 5, 6: Fasteners 8, 8a, 80, 800: Bonding material 21: Recess 40, 40a, 40b: Inset piece 43: Steel plate body 51: Bolt 52: Nut 300, 300a: Insertion material
Claims
1. A joint structure for the end of a bamboo laminated timber, A plate-shaped protrusion is held in place while embedded in the aforementioned bamboo laminated material, A load transmission section that transmits tensile load from the end of the bamboo laminated timber to the protruding part, A joining structure characterized by having the following features.
2. The load transmission portion is a steel plate extending from the object to be joined. The joining structure according to claim 1, characterized in that the protrusion is provided on the surface of the steel plate that is on the bamboo laminated wood side.
3. The steel plates are arranged on both sides of the bamboo laminated material. The joining structure according to claim 2, characterized in that the steel plates on both sides of the bamboo laminate are fastened together using bolts and nuts.
4. The joining structure according to claim 2, characterized in that the steel plate is arranged to cover the entire circumference of the cross-section of the bamboo laminated timber.
5. Steel plates are placed on both sides of the aforementioned bamboo laminated material. The aforementioned protrusions are provided on the bamboo laminated material side of both steel plates. Steel plates placed on both sides of the aforementioned laminated bamboo material are fastened together using bolts and nuts that penetrate the laminated bamboo material. The load transmission section includes the bolt and an insert member that extends from the object to be joined and is inserted into the interior of the bamboo laminated timber. The joint structure according to claim 1, characterized in that the bolt is passed through the insert material.
6. The joint structure according to claim 1, characterized in that a recess for fitting the convex portion is formed in advance in the bamboo laminated material.