Buckling-restrained brace
The buckling-restrained brace design with a steel core and separate fastening components for wooden bending resistance members addresses the weakness of wooden restraints, ensuring structural integrity and reducing manufacturing effort by allowing gaps, thus enhancing buckling restraint performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2023-06-30
- Publication Date
- 2026-06-23
AI Technical Summary
Buckling-restrained braces using wood as a restraining material face challenges due to the low strength of wooden restraints, which can break when the core buckles, and the formation of gaps between the core and restraint materials, necessitating strict manufacturing controls to prevent damage, increasing effort and cost.
A buckling-restrained brace design featuring a steel core material sandwiched by buckling-restraining members and wooden bending resistance members, with spacers and separate fastening components to absorb manufacturing errors and reduce the risk of wood fracture, allowing for gaps between the core and restraint materials.
This design effectively prevents wood fracture and reduces manufacturing effort by allowing for gaps between the core and restraint materials, ensuring sufficient buckling restraint performance without strict tolerance controls, enhancing structural integrity and cost-effectiveness.
Smart Images
Figure 0007878183000001 
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Figure 0007878183000003
Abstract
Description
Technical Field
[0001] The present invention relates to a buckling restraint brace using wood.
Background Art
[0002] In a building, braces may be provided as members that resist shear forces during an earthquake. The braces are provided obliquely in the plane of the frame of columns and beams, and are mainly members that resist the shear deformation of the layers caused by earthquake loads. During an earthquake, axial tensile and compressive loads act repeatedly, so the brace is required to have sufficient strength and deformation capacity against both loads.
[0003] Generally, when an axial compressive load acts, there is a risk of buckling in the member, and the buckling reduces the strength and deformation capacity of the member. In a brace, a reduction in strength and deformation capacity due to buckling can also occur. Therefore, there is a buckling restraint brace composed of a core material that resists earthquake loads and a buckling restraint material arranged to cover the periphery of the core material to suppress the buckling deformation of the core material. FIGS. 16 and 17 show such a buckling restraint brace 51 arranged in the plane of a frame composed of columns 53 and beams 55.
[0004] The buckling restraint material is required to have sufficient strength against the bending deformation due to the buckling of the core material, and the buckling restraint material or the joint of the buckling restraint material is required to have sufficient strength against the local compressive force due to the buckling deformation of the core material. FIG. 18 is a cross-sectional view of a conventional buckling restraint brace 51 composed of a steel core material 57 and a steel restraint material 59. As the cross-sectional shape of the conventional core material 57, there are a plate (see FIG. 18(a)), a circular shape (see FIG. 18(b)), a cross (see FIG. 18(c)), an H shape (see FIG. 18(d)), etc. The restraint material 59 covering the core material 57 is often box-shaped (see FIGS. 18(a), (c), (d)) or circular (see FIG. 18(b)).
[0005] The local compressive force due to the buckling deformation of the core material 57 is proportional to the compressive load acting on the core material 57 and the amount of buckling deformation of the core material 57. Therefore, the larger the gap between the restraining member 59 and the core material 57, the higher the load-bearing capacity required of the restraining member 59. For this reason, some designs include filling material 61 such as mortar in the gap between the restraining member 59 and the core material 57 (see Figure 18(a)). In addition, some designs involve applying or attaching an unbonding material 63 to the restraining material 59 to prevent the axial force of the core material 57 from flowing through it (see Figure 18(a)).
[0006] Regarding the connection between both ends of the buckling-restrained brace 51 and the frame, there are two types: one with a bolted connection 65, as shown in Figure 16, and another with a pin connection 67, as shown in Figure 17. In all cases, the width of the core material 57 near the joint is increased, high-strength steel is used, and reinforcing ribs are provided to increase the load-bearing capacity of the core material 57 and prevent plastic deformation, thus preventing the joint from failing prematurely. In addition, because the restraining material 59 is made of steel, localized failure due to contact with the core material 57 is unlikely to occur.
[0007] On the other hand, the use of wood is being promoted in recent years due to concerns about CO2 emissions. Since wood burns in the event of a fire, it is sometimes used for columns and beams in buildings after being treated to be fire-resistant. In addition, wood is sometimes used in steel structures, such as in floor slabs, and recently, the use of wood as a bracing material is being considered.
[0008] Patent Document 1 proposes a buckling-restrained brace consisting of a steel plate-shaped core material and a pair of wooden restraining members placed on both sides of the wide surface of the core material, with the two being bolted together at both ends in the axial direction. Furthermore, Patent Document 1 proposes a buckling-restrained brace in which a pair of wooden restraining members are arranged to sandwich both sides of the web of an H-shaped core material.
[0009] Patent Document 2 proposes a buckling-restrained brace composed of a steel plate-shaped core material, wooden restraining members positioned on both sides of the core material in the thickness direction, and spacers positioned on both sides of the core material in the width direction. In the buckling-restrained brace of Patent Document 2, the thickness of the spacers is made less than or equal to the thickness of the core material so that no gap is created between the core material and the restraining members. This reduces the load on the restraining members caused by the buckling of the core material and prevents damage to the restraining members.
[0010] Patent Document 3 also proposes a buckling-restrained brace consisting of a steel core and a wooden restraining member, and, similar to Patent Document 2, it is designed to prevent gaps from forming between the core and the restraining member. [Prior art documents] [Patent Documents]
[0011] [Patent Document 1] Japanese Patent Publication No. 2019-214881 [Patent Document 2] Patent No. 6942280 [Patent Document 3] Japanese Patent Publication No. 2022-53009 [Overview of the project] [Problems that the invention aims to solve]
[0012] As shown in Patent Documents 1 to 3, buckling-restrained braces consisting of a steel core and wooden restraints have been proposed. However, because the wooden restraints have low strength, there is a risk that they may break when the core buckles and the restraints are pressed against the core.
[0013] As mentioned above, the larger the gap between the restraint material and the core material, the greater the local compressive force, making the restraint material more prone to damage. Therefore, it is necessary to devise ways to prevent the formation of gaps between the core material and the restraint material, as described in Patent Documents 2 and 3. However, even if measures are taken to prevent gap formation, in reality, there is a high possibility that gaps will form between the core material and the restraint material due to initial defects or dimensional errors that inevitably occur during manufacturing, and depending on the size of the gap, sufficient buckling restraint may not be obtained.
[0014] Therefore, in order to prevent the above-mentioned gaps from occurring, it is necessary to strictly limit the tolerance for initial defects and dimensional errors, requiring rigorous manufacturing control. Furthermore, if initial defects or dimensional errors do not fall within the tolerance range, numerous rework and corrections will be required, making the manufacturing process time-consuming.
[0015] As mentioned above, although the use of wood is being promoted, when using wood as a restraining material for buckling-restrained braces, it is necessary to take measures to prevent gaps from forming between the core material and the restraining material in order to ensure sufficient buckling restraint performance, which increases the effort required for manufacturing and is problematic.
[0016] This invention was made to solve the aforementioned problems, and aims to provide a buckling-restrained brace that can prevent wood fracture without strictly limiting the gap between the core material and the restraining material, and that can reduce the effort required for manufacturing. [Means for solving the problem]
[0017] (1) The buckling-restrained brace according to the present invention is characterized by comprising: a plate-shaped steel core material; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling-restraining members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling-restraining member fastening component for fastening the two buckling-restraining members together; two wooden bending resistance members arranged on the side of the buckling-restraining member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling-restraining member fastening component.
[0018] (2) In addition, in the case described in (1) above, the bending resistance member is characterized in that it is made of a wood material formed by bonding and laminating a plurality of wood pieces in the width direction of the core material.
[0019] (3) In addition, the above-mentioned (1) or (2) is characterized in that the spacer and the buckling restraint member are made of steel, and the contact surface between the spacer and the buckling restraint member is treated with a friction surface treatment.
[0020] (4) Further, in the one described in the above (1) or (2), a through-hole for inserting the bending resistance member fastening component is provided in the bending resistance member, and the hole diameter of the through-hole is equivalent to the shaft diameter of the bending resistance member fastening component.
[0021] (5) Further, in the one described in the above (4), the bending resistance member fastening component is composed of a bolt and a nut, and the head of the bolt and the nut are arranged in a counterbore provided at the end of the through-hole of the bending resistance member, and a wooden plug for covering the head of the bolt and the nut is provided in the counterbore.
[0022] (6) Further, in the one described in the above (1) or (2), lubricants are applied to both surfaces of the core material.
[0023] (7) Further, in the one described in the above (1) or (2), the bending resistance member fastening component is provided so as to penetrate the buckling restraint material and the spacer, and the buckling restraint material fastening component and the bending resistance member fastening component are provided at positions offset in the longitudinal direction of the brace.
[0024] (8) Further, in the one described in the above (1) or (2), wooden decorative materials for making the buckling restraint material and the spacer invisible from the outside are further provided on both side surfaces in the plate width direction of the buckling restraint material.
[0025] (9) Further, in the one described in the above (8), the bending resistance member fastening component penetrates the decorative material.
Advantages of the Invention
[0026] In this invention, two buckling restraint members are placed on both sides of the core material in the thickness direction via spacers, and these two buckling restraint members are fastened together with buckling restraint member fastening components. In conventional structures, the wood and the fastening components resist the local compressive force when the core material buckles, whereas in this invention, the buckling restraint members and buckling restraint member fastening components resist the local compressive force, thus significantly suppressing the local compressive force applied to the wooden bending resistance member. Therefore, it is not necessary to strictly limit the gap between the core material and the buckling restraint members, and the manufacturing effort can be reduced. [Brief explanation of the drawing]
[0027] [Figure 1] This is a cross-sectional view of the buckling-restrained brace according to the embodiment (corresponding to the DD section as seen by the arrow in Figure 5(a)). [Figure 2] This is a cross-sectional view of the buckling-restrained brace according to the embodiment (corresponding to the EE section as seen by the arrow in Figure 5(a)). [Figure 3] This is a diagram (part 1) illustrating the internal structure of a buckling-restrained brace according to an embodiment. Figure 3(a) is a view of the core material from the width direction of the plate, and Figure 3(b) is a view taken along arrow AA in Figure 3(a). [Figure 4] This is a diagram (part 2) illustrating the internal structure of a buckling-restrained brace according to an embodiment. Figure 4(a) is a view of the core material from the width direction of the plate, and Figure 4(b) is a view of the BB arrow in Figure 4(a). [Figure 5] This is the third diagram illustrating the internal structure of the buckling-restrained brace according to the embodiment. Figure 5(a) is a view of the core material from the width direction of the plate, and Figure 5(b) is a view of the CC arrow in Figure 5(a). [Figure 6] This figure shows the buckling-restrained brace in Figure 1 with the bending resistance member fastening component removed. [Figure 7] This is an explanatory diagram of another embodiment of the bending resistance member (corresponding to the DD section as seen by the arrow in Figure 5(a)). [Figure 8] This is an explanatory diagram of another embodiment of the bending resistance member (corresponding to the EE section as seen by the arrow in Figure 5(a)). [Figure 9] This is an explanatory diagram of another embodiment 1 of the buckling-restrained brace according to the embodiment. [Figure 10] This is an explanatory diagram of another embodiment 2 of the buckling-restrained brace according to the embodiment. [Figure 11] This is an explanatory diagram of another embodiment 3 of the buckling-restrained brace according to the embodiment. [Figure 12] Figure 11 shows the manufacturing process of another embodiment 3 of the buckling-restrained brace. [Figure 13] This is an explanatory diagram of another embodiment 4 of the buckling-restrained brace according to the embodiment. [Figure 14] This figure shows a comparative example related to the example. [Figure 15] This figure shows an example of the invention according to the embodiment. [Figure 16] This is an explanatory diagram (part 1) of a typical buckling-restrained brace installed within a structural plane. [Figure 17] This is a diagram (part 2) illustrating a typical buckling-restrained brace installed within a structural plane. [Figure 18] This is an explanatory diagram of the core material and restraint material of a typical buckling-restrained brace. [Modes for carrying out the invention]
[0028] The buckling-restrained brace 1 according to this embodiment will be described with reference to Figures 1 to 5. Figure 1 corresponds to the DD section in the line of arrow 5(a), and shows the cross-section of the buckling-restrained brace 1 where the reinforcing rib 13 is not provided. Figure 2 corresponds to the EE section in the line of arrow 5(a), and shows the cross-section of the buckling-restrained brace 1 where the reinforcing rib 13 is provided.
[0029] As shown in Figures 1 and 5, the buckling-restrained brace 1 mainly consists of a steel, plate-shaped core material 3, two buckling-restraining members 5 positioned to sandwich the core material 3, and two wooden bending-resistance members 7 positioned to sandwich the two buckling-restraining members 5. To make this internal structure easier to understand, Figure 3 shows only the core material 3, and Figure 4 shows only the core material 3 and the buckling-restraining members 5. The following describes each component in detail.
[0030] <Core material> As shown in Figure 3, the core material 3 is a plate-like body made of steel with a rectangular cross-section, and the longitudinal end of the core material 3 is a joint 9 for joining the buckling-restrained brace 1 to the frame. In this embodiment, both ends of the buckling-restrained brace 1 are bolted to the frame with high-strength bolts, so bolt holes 11 are provided in the joint 9. However, in the case of a pin joint type, a clevis is provided in the joint 9.
[0031] Furthermore, reinforcing ribs 13 are provided at both longitudinal ends of the core material 3 to prevent plastic deformation. The reinforcing rib 13 is a plate material joined to the core material 3 by fillet welding or partial penetration welding so as to be perpendicular to the wide surface of the core material 3, and a cross cross section is formed by the core material 3 and the reinforcing rib 13 within the joining area of the reinforcing rib 13 (see Figure 2).
[0032] Furthermore, it is preferable that a lubricant is applied to both sides of the core material 3. If the sliding properties between the core material 3 and the buckling restraint material 5 are poor, when the core material 3 buckles and comes into contact with the buckling restraint material 5, a longitudinal load will be applied to the buckling restraint material 5 by the amount of frictional force, which may accelerate failure. Therefore, by applying a lubricant to both sides of the core material 3 to improve the sliding properties between the core material 3 and the buckling restraint material 5, the load acting on the buckling restraint material 5 can be reduced.
[0033] <Buckling restraint material> The buckling restraint member 5 is a plate-shaped member that is positioned on both sides of the core material 3 in the thickness direction. Spacers 15 are placed on both sides of the core material 3 in the width direction of the plate, and the buckling restraint member 5 is positioned to sandwich the core material 3 via these spacers 15. The spacers 15 may be long members extending in the longitudinal direction of the brace, or they may be divided and arranged in the longitudinal direction of the brace.
[0034] The two buckling restraint members 5, positioned to sandwich the core material 3, are fastened together by a buckling restraint member fastening component 17. In this embodiment, the buckling restraint member fastening component 17 consists of a bolt 19 and a nut 21, and the buckling restraint member 5 and the spacer 15 are provided with through holes 5a and 15a, respectively, for passing the bolt 19 through.
[0035] The buckling restraint fastening components 17 are provided in one row on each side of the core material 3 so as not to interfere with the core material 3. Since buckling of the core material 3 can occur along its entire length, the buckling restraint fastening components 17 are provided along the entire length of the buckling restraint 5 in the longitudinal direction (see Figure 4).
[0036] Furthermore, a slit 5b larger than the shape of the reinforcing rib 13 is provided at the longitudinal end of the buckling restraint member 5 so as not to interfere with the reinforcing rib 13 (see Figures 2 and 4(b)). If the buckling restraint member 5 may interfere with the weld between the reinforcing rib 13 and the core material 3, the buckling restraint member 5 may be cut out to match the shape of the weld.
[0037] While the present invention does not limit the material of the buckling restraint member 5, since the buckling restraint member 5 resists the buckling deformation of the core material 3, a highly rigid material such as concrete or steel is desirable. For the same reason, it is desirable to use a component with high strength and rigidity, such as a bolt 19 and a nut 21, for the buckling restraint member fastening component 17 of the present invention.
[0038] In this embodiment, the thickness of the spacer 15 is greater than the thickness of the core material 3, which creates a gap S between the core material 3 and the buckling restraint member 5 (see Figure 1). By providing a gap S between the core material 3 and the buckling restraint member 5 in this way, manufacturing errors of the core material 3 and the buckling restraint member 5 can be absorbed, and manufacturing costs can be reduced. Note that the gap S is not essential in this invention, so the thickness of the spacer 15 may be the same as the thickness of the core material 3.
[0039] Furthermore, both the spacer 15 and the buckling restraint member 5 may be made of steel, in which case it is advisable to apply a friction surface treatment to the contact surfaces of the spacer 15 and the buckling restraint member 5. Specific examples of friction surface treatment include applying red rust or creating irregularities on the surface. By applying a friction surface treatment, displacement between the spacer and the buckling restraint member 5 can be suppressed, and higher buckling restraint performance can be expected.
[0040] <Bending resistance member> The bending resistance member 7 is a wooden member positioned on the side of the buckling restraint member 5 opposite to the core material 3. Two bending resistance members 7, positioned to sandwich two buckling restraint members 5, are fastened together by bending resistance member fastening components 23. These fastening components 23 can be drift pins, lag screw bolts, or the like, and the bending resistance members 7 are provided with through holes 7a for passing the fastening components 23 through. As described above, the two buckling restraint members 5 and the two bending resistance members 7 are fastened together by separate fastening components.
[0041] In the examples shown in Figures 1 to 5, the bending resistance member 7 is wider than the buckling restraint member 5 so that the bending resistance member fastening components 23 do not interfere with the buckling restraint member 5, and the bending resistance member fastening components 23 are positioned on the outside of both sides of the buckling restraint member 5. In addition, similar to the buckling restraint member fastening components 17, the bending resistance member fastening components 23 are provided in one row on each side in the width direction of the bending resistance member 7, along the entire length in the longitudinal direction of the bending resistance member 7 (see Figure 5).
[0042] The surface of the bending resistance member 7 that contacts the buckling restraint member 5 is provided with a counterbore 7b to avoid interference with the bolts 19 and nuts 21 that fasten the buckling restraint member 5. Furthermore, the longitudinal end of the bending resistance member 7 is provided with a slit 7c, similar to the buckling restraint member 5, to prevent interference with the reinforcing rib 13 (see Figures 2 and 5(b)).
[0043] As mentioned above, the buckling restraint member 5 is made of a material with higher rigidity than wood, such as concrete or steel, and is a member that exhibits high resistance to local compressive forces generated by contact with the core material 3. However, because it is a plate-like body, it is prone to bending and deforming into an arc when compressive force is applied to the core material 3. Therefore, by sandwiching the buckling restraint member 5 with the bending resistance member 7, the bending rigidity of the buckling restraint member 5 is reinforced, and the above bending deformation is prevented.
[0044] Furthermore, from the viewpoint of ensuring resistance to bending of the buckling restraint member 5, it is desirable that the diameter of the through hole 7a of the bending resistance member 7 be the same as the shaft diameter of the bending resistance member fastening component 23 (see Figure 6). By ensuring that the inner circumferential surface of the through hole 7a and the bending resistance member fastening component 23 are in close contact and no gap is created, the two bending resistance members 7 behave as a single unit. This increases the resistance to bending and allows for the exercise of high bending rigidity, thereby suppressing the bending deformation of the core material 3 when the brace is compressed.
[0045] As described above, this embodiment consists of a plate-shaped core material 3 sandwiched between two plate-shaped buckling restraint members 5, and further sandwiched from the outside by two wooden bending resistance members 7, so that the core material 3 does not directly touch the wooden bending resistance members 7. Therefore, the local compressive force due to buckling of the core material 3 is less likely to act on the wood, and damage to the wood can be prevented. In addition, by making the buckling restraint members 5 plate-shaped, the increase in cross-sectional size is suppressed.
[0046] Compared to conventional examples in which the core material is directly sandwiched between wooden buckling restraint members, this embodiment eliminates the need to strictly control the gap between the core material 3 and the buckling restraint member 5, thereby reducing manufacturing effort. Furthermore, by allowing a gap between the core material 3 and the buckling restraint material 5, it becomes possible to intentionally create a gap S as shown in Figure 1 to absorb initial defects and dimensional errors, thereby reducing manufacturing costs.
[0047] Regarding the provision of other components between the core material and the wood, Patent Document 2 describes a method in which a steel plate that is in close contact with the core material is inserted between the wooden buckling restraint material and the core material, and these are then integrated together with bolts or the like (see Figure 11 of Patent Document 2). However, the above method does not sufficiently prevent damage to the wood. This point will be explained below.
[0048] In the method described in Patent Document 2 above, the core material, the internal steel plate, and the wooden buckling restraint member are integrated with bolts. Therefore, when the core material buckles, a large bending moment is applied to the wood between the bolts via the internal steel plate, and a strong tensile force acts on the bolts. This can cause bending failure of the wood or indentation failure of the wood at the bolt fastening points, potentially impairing the buckling restraint performance.
[0049] In contrast, in this embodiment, the wood (bending resistance member 7) and the buckling restraint member 5 located immediately adjacent to the core material 3 are fastened together with separate components. As a result, when the core material 3 buckles, the buckling restraint member 5 and the buckling restraint member fastening component 17 immediately adjacent to the core material 3 strongly resist most of the load acting on the bending resistance member 7 and the bending resistance member fastening component 23. Therefore, the load acting on the bending resistance member 7 and the bending resistance member fastening component 23 is reduced, and damage to the wood can be prevented.
[0050] Furthermore, if there is a gap between the core material 3 and the buckling restraint member 5, the load acting on the buckling restraint member 5 when the core material 3 buckles will increase. However, in this embodiment, for the reasons mentioned above, even if a gap S between the core material 3 and the buckling restraint member 5 is allowed, the bending resistance member 7 is less likely to be damaged, and high buckling restraint performance can be ensured.
[0051] Furthermore, as shown in Figures 7 and 8, the bending resistance member 7 can be made of wood-based material (such as laminated timber or LVL) in which multiple pieces of wood 25 are bonded and laminated in the width direction of the core material 3. In this embodiment, the bending resistance member 7 is expected to have a large dimension in the width direction of the core material 3 due to its configuration. However, by making the width direction of the core material the same as the adhesive lamination direction, as shown in Figures 7 and 8, it becomes easy to prepare a bending resistance member 7 with a large dimension in the width direction of the core material.
[0052] Furthermore, while the above description shows examples of using drift pins or lag screw bolts as the bending resistance member fastening components 23, in other embodiments, the bending resistance member fastening components 23 may be composed of bolts and nuts. An example of this is shown in Figure 9. In another embodiment of this design, the buckling-restrained brace 27, as shown in Figure 9, has two bending resistance members 7 fastened together by a bending resistance member fastening component 23 consisting of a bolt 29 and a nut 31.
[0053] The bending resistance member 7 is provided with a through hole 7a for inserting a bolt 29, and a counterbore 7d is formed at the end of the through hole 7a. The head of the bolt 29 and the nut 31 are positioned within the counterbore 7d, and a wooden plug 33 is provided in the counterbore 7d to cover the head of the bolt 29 and the nut 31. As described above, when a bolt 29 and a nut 31 are used as fastening components 23 for the bending resistance member, the head of the bolt 29 and the nut 31 are hidden from view from the outside by providing a counterbore 7d and a wooden plug 33 in the bending resistance member 7, thereby improving the aesthetic appearance.
[0054] Furthermore, in the above description, the bending resistance member fastening component 23 was provided so as to pass through the outside in the width direction of the buckling restraint member 5 and the spacer 15. In other embodiments, the bending resistance member fastening component 23 may be provided so as to penetrate the buckling restraint member 5 and the spacer 15. An example of this is shown in Figure 10. Figure 10(a) is a view of a buckling-restrained brace 35, which is another embodiment 2 of this model, as seen from the plate width direction of the core material 3. Figure 10(b) is a view corresponding to the FF cross section as seen by the arrow in Figure 10(a), and Figure 10(c) is a view corresponding to the GG cross section as seen by the arrow in Figure 10(a).
[0055] The buckling-restrained brace 35 has through-holes 5a and 15a for passing through the buckling-restrained member fastening component 17, as well as through-holes 5c and 15b for passing through the bending-resistance member fastening component 23 (see Figure 10(c)). The two bending-resistance members 7 are fastened together by the bending-resistance member fastening component 23, which passes through the buckling-restrained member 5, the spacer 15, and the bending-resistance member 7.
[0056] In the example described above, the buckling restraint fastening component 17 and the bending resistance member fastening component 23 were positioned at the same location along the longitudinal direction of the brace. However, in the example shown in Figure 10, the two components are positioned offset along the longitudinal direction of the brace so as not to interfere with each other. Note that in examples other than Figure 10, the buckling restraint fastening component 17 and the bending resistance member fastening component 23 are shown positioned at the same location along the longitudinal direction of the brace for easier understanding of the configuration, but there is no problem if they are positioned at different locations along the longitudinal direction of the brace.
[0057] In this embodiment, the bending resistance member fastening component 23 can be provided near both sides of the core material 3 in the plate width direction, so the dimensions of the bending resistance member 7 in the plate width direction of the core material 3 can be reduced, and miniaturization and weight reduction can be expected. Furthermore, when viewed from the width direction of the core material 3, the bending resistance member fastening component 23 is not exposed, thus improving the aesthetic appearance.
[0058] In this example, the bending resistance member fastening component 23 penetrates the buckling restraint member 5, but since the buckling restraint member 5 and the bending resistance member 7 are fastened together by separate components, as in the previously mentioned example, this does not impair the load reduction effect acting on the bending resistance member 7.
[0059] As mentioned above, the example in Figure 10 improves the aesthetics because the bending resistance member fastening component 23 is not exposed. However, the distance between the buckling restraint member fastening component 17 and the bending resistance member fastening component 23 tends to be small, so care must be taken to prevent interference between them. Also, if there is insufficient space, the configuration shown in Figure 10 may not be feasible. Therefore, as another embodiment to improve the design, wooden decorative materials may be further provided on both sides of the buckling restraint member 5 in the width direction of the plate to conceal the buckling restraint member 5 and the spacer 15 from external view. An example of this is shown in Figure 11. Another embodiment of this model, the buckling-restrained brace 37, has a similar configuration to the buckling-restrained brace 1 in Figure 1, but as shown in Figure 11, a wooden decorative material 39 is provided between the upper and lower bending resistance members 7. The decorative material 39 may be a long member that is elongated in the longitudinal direction of the brace, or it may be divided and arranged in a line in the longitudinal direction of the brace (see Figure 12(a)).
[0060] The size of the decorative material in the thickness direction of the core plate is equal to or greater than the sum of the thickness of the spacer 15 and the thickness of the two buckling restraint members 5, so that it can cover the buckling restraint member 5, the spacer 15, and the bending resistance member fastening component 23.
[0061] By providing decorative material 39 on both sides of the buckling restraint member 5 in the width direction of the plate, specifically further outward from the position where the bending resistance member fastening component 23 is provided, the buckling restraint member 5, spacer 15, and bending resistance member fastening component 23 are not exposed in the width direction of the core material plate, thereby improving the aesthetic appearance.
[0062] The decorative material 39 may simply be fitted between the two bending resistance members 7, but it is preferable to join it to one of the bending resistance members 7 to improve manufacturability. This point will be explained using Figure 12. Figure 12(a) shows the state of the manufacturing process of the buckling-restrained brace 37 in Figure 11, and Figure 12(b) is a cross-sectional view taken along the arrow HH in Figure 12(a). As shown in Figure 12, by joining the decorative material 39 to one of the bending resistance members 7 (the lower bending resistance member 7 in Figure 12), the position of the decorative material 39 can be fixed during manufacturing, improving manufacturability. The decorative material 39 may be joined to the bending resistance member 7 by screws, or by nails or adhesive.
[0063] The above is an example in which a decorative material 39 is provided on the outside of the bending resistance member fastening component 23, but it is also possible to configure the bending resistance member fastening component 23 to pass through the decorative material 39. Such an example is shown in Figure 13. In another embodiment 4 of this design, the buckling-restrained brace 41, the thickness of the decorative material 39 is greater than in the example in Figure 11, and a through hole 39a is formed in the decorative material 39 for passing the bending resistance member fastening component 23 through. The two bending resistance members 7 are then fastened together by a bending resistance member fastening component 23 that penetrates the decorative material 39 and the bending resistance members 7, as shown in Figure 13. In this example, as in the example in Figure 11, the buckling restraint member 5, spacer 15, and bending resistance member fastening component 23 are not exposed in the width direction of the core material plate, improving the aesthetic appearance. Furthermore, since the decorative material 39 is fastened by the bending resistance member fastening component 23, the decorative material 39 becomes integrated with the opposing bending resistance member 7, thereby improving the rigidity of the bending resistance member 7. [Examples]
[0064] The stiffening capacity of the present invention against local loads caused by buckling of the core material was investigated. Specifically, the difference in stiffening capacity with and without fastening members connecting the buckling restraint members 5 was examined. The following explanation will be given with reference to Figures 14 and 15. Figure 14 shows the buckling-restrained brace 43, a comparative example, under localized load. The buckling-restrained brace 43 has the buckling-restraining member 5 and the bending-resistance member 7 fastened together with the same fastening component 45. The fastening component 45 consists of a bolt 47 and a nut 49. Figure 15 shows the state in which a local load is applied to the buckling-restrained brace 1 of Figure 1, which is an example of the present invention. As mentioned above, the buckling-restrained brace 1 has the buckling-restraining member 5 and the bending-resistance member 7 fastened together with separate fastening components.
[0065] First, we will explain the behavior of the comparative example in Figure 14 when a localized load is applied. As shown in Figure 14, when the buckling restraint member 5 and the bending resistance member 7 are fastened together with the same fastening component 45, when an extrusive force is applied to the buckling restraint member 5 and the bending resistance member 7 by the buckled core material 3, the fastening component 45 that fastens them together resists this force. At this time, a tensile force acts on the fastening component 45, and a local stress acts on the contact portion between the fastening component 45 and the bending resistance member 7. As a result, the bolts 47 and nuts 49 of the fastening component 45 may become embedded in the bending resistance member 7, which can cause the bending resistance member 7 to break.
[0066] Furthermore, as the fastening components 45 resist the extruding force of the core material 3, bending deformation occurs in the bending resistance member 7 and the buckling restraint member 5 with the fastening components 45 as the fulcrum, and a strong bending moment acts between the fastening components 45 on both sides in the width direction of the core material 3. In some cases, the bending resistance member 7 may break due to such a bending moment. For the reasons stated above, in the comparative example configuration, there is a risk that the wooden bending resistance member 7 will break when the core material buckles.
[0067] Here, in a given cross-section, if P is the local extruding force due to buckling of the core material 3, and u is the distance between the fastening components 45 on both sides of the core material 3 in the width direction, then the load acting on each fastening component 45 can be expressed as P / 2, and the bending moment acting on the bending resistance member 7 can be expressed as P / 2 × u / 2 = Pu / 4.
[0068] Next, we will explain the behavior of the example of the invention shown in Figure 15 when a local load is applied. As shown in Figure 15, when the buckling restraint member 5 and the bending resistance member 7 are fastened together by separate components, the buckling restraint member fastening component 17 strongly resists the extruding force due to buckling of the core material 3. Therefore, the bending resistance member 7 bears the load remaining after deducting the load borne by the buckling restraint member fastening component 17.
[0069] Therefore, if the load borne by each buckling-restraining member fastening component 17 is Pa / 2, then the load borne by each bending-resistance member fastening component 23 is (P-Pa) / 2, and the bending moment acting on the bending-resistance member 7 is (P-Pa)u / 4. As described above, the present invention is preferable because, compared to the comparative example, the force acting on the bending resistance member fastening component 23 and the bending moment acting on the bending resistance member 7 are reduced, making it less likely for the bending resistance member 7 to break.
[0070] In particular, if the buckling restraint member 5 and the buckling restraint member fastening component 17 have sufficient strength and rigidity against localized extruding forces P, the bending resistance member 7 and the bending resistance member fastening component 23 may be a mechanism that provides almost no resistance to localized extruding forces P (drift pin, round bar), and sufficient stiffening performance can be obtained as long as the bending resistance member fastening component 23 prevents displacement of the core material axial direction of the pair of bending resistance members 7. [Explanation of symbols]
[0071] 1. Buckling-restrained brace 3 Core material 5. Buckling restraints 5a through hole 5b Slit 5c through hole 7 Bending resistance member 7a Through hole 7b Counterbore 7c slit 7d Counterbore 9 Joint 11 bolt holes 13 Reinforcement Ribs 15 Spacers 15a through hole 15b Through hole 17 Buckling Restraint Fastening Components 19 volts 21 nuts 23. Fastening components for bending resistance members 25 Wood Piece 27 Buckling-restrained brace (other embodiment 1) 29 volts 31 nuts 33 Wood plug 35 Buckling-restrained brace (other embodiment 2) 37 Buckling-restrained brace (other embodiment 3) 39 Decorative materials 39a through hole 41 Buckling-restrained brace (other embodiment 4) 43. Buckling-restrained brace (comparative example) 45 Fastening components 47 volts 49 Nuts 51 Buckling-restrained brace (conventional example) 53 pillars 55 Beam 57 Core material 59 Restraint material 61 Filling material 63 Unbonded material 65 Bolt joint 67 Pin joint S Gap
Claims
1. The device comprises a plate-shaped steel core material, spacers positioned on both sides of the core material in the width direction, two plate-shaped buckling restraint materials positioned on both sides of the core material in the thickness direction via the spacers, a buckling restraint fastening component for fastening the two buckling restraint materials together, two wooden bending resistance members positioned on the side of the buckling restraint material opposite to the core material, and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint fastening component, A buckling-restrained brace characterized in that the thickness of the spacer is greater than the thickness of the core material, and a gap is created between the core material and the buckling-restraining member.
2. The buckling-restrained brace according to claim 1, characterized in that the bending resistance member is provided with a through hole for inserting the bending resistance member fastening component, and the diameter of the through hole is equal to the shaft diameter of the bending resistance member fastening component.
3. The buckling restraint brace according to claim 1, further comprising wooden decorative materials on both sides of the buckling restraint member in the width direction of the plate, for concealing the buckling restraint member and spacer from external view.
4. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, The buckling-restrained brace is characterized in that the bending resistance member is made of a wood material formed by bonding and laminating a plurality of wood pieces in the width direction of the core material.
5. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, A buckling-restrained brace characterized in that the spacer and the buckling-restraining member are made of steel, and the contact surfaces of the spacer and the buckling-restraining member are treated with a friction surface treatment.
6. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, The bending resistance member is provided with a through hole for inserting the bending resistance member fastening component, and the diameter of the through hole is equal to the shaft diameter of the bending resistance member fastening component. The buckling-restrained brace is characterized in that the fastening component for the bending resistance member is composed of a bolt and a nut, the head of the bolt and the nut are positioned in a counterbore provided at the end of the through hole of the bending resistance member, and a wooden plug is provided in the counterbore to cover the head of the bolt and the nut.
7. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, A buckling-restrained brace characterized in that a lubricant is applied to both sides of the core material.
8. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, The buckling-restrained brace is characterized in that the bending resistance member fastening component is provided so as to penetrate the buckling-restraining member and the spacer, and the buckling-restraining member fastening component and the bending resistance member fastening component are provided at positions offset in the longitudinal direction of the brace.
9. A steel core material in the shape of a plate; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint members arranged on both sides of the core material in the plate thickness direction via the spacers; a buckling restraint member fastening component for fastening the two buckling restraint members together; two wooden bending resistance members arranged on the side of the buckling restraint member opposite to the core material; and a bending resistance member fastening component for fastening the bending resistance members together separately from the buckling restraint member fastening component, The buckling restraint member is further provided with wooden decorative materials on both sides in the width direction of the plate to conceal the buckling restraint member and spacer from external view. The buckling-restrained brace is characterized in that the bending resistance member fastening component penetrates the decorative material.
10. The buckling-restrained brace according to any one of claims 1, 2, 3, 5 to 9, characterized in that the bending resistance member is made of a wood material obtained by bonding and laminating a plurality of wood pieces in the board width direction of the core material.