Buckling-restrained brace

Abstract

To provide a buckling restraint brace which is suitable for use by being incorporated into a frame of a wooden building or the like, and can suppress manufacturing costs.SOLUTION: A buckling restraint brace 100 includes: a core material 10 that is formed of one first steel plate 11 and two second steel plates 12 that are joined perpendicularly to a wide surface of the first steel plate 11, and has a cross-sectional shape; and a restraining material 20 that includes wooden shaft members 21 arranged in four arrangement areas A3 formed by the first steel plate 11 and the second steel plate 12 respectively and extending in a longitudinal direction of the core material 10, and connecting means 22 for connecting adjacent wooden shaft members 21 to each other.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a buckling restraint brace.

Background Art

[0002] Conventionally, as braces for forming building structures (column-beam structures, roof structures, etc.), buckling restraint braces with buckling prevention measures have been applied. As buckling restraint braces, there are various bracing forms such as a form in which only steel plates reinforce around a steel core material, a form in which RC (Reinforced Concrete) reinforces around a steel core material, and a form in which a steel core material is covered with steel and mortar.

[0003] By the way, recently, efforts have been made to improve the fire resistance and seismic resistance of wooden buildings (wooden houses, wooden warehouses, wooden stadiums, etc.). Wooden houses inherently have advantages such as a high degree of freedom in floor plans and designs, a soothing effect due to natural wood, a humidity control effect of wood, and generally lower construction costs compared to steel-frame or RC structures depending on the building use such as houses. However, the improvement of the above-mentioned fire resistance and seismic resistance is one of the factors increasing the attention of wooden buildings including wooden houses. When incorporating the above-mentioned conventional buckling restraint braces into the structure of such wooden houses, it is inevitable that wooden columns and beams and buckling restraint braces having metal or concrete reinforcing materials will coexist, resulting in an unbalanced appearance.

[0004] Therefore, a measure can be considered to cover the entire buckling restraint brace with a wooden or paper panel or the like so that the metal or concrete reinforcing material cannot be visually recognized from the outside. However, this measure requires a great deal of labor, so there is a concern about an increase in construction costs. In addition, since conventional buckling restraint braces use a lot of metal, concrete, mortar, etc., they tend to be heavy, and it is structurally unbalanced to attach a heavy buckling restraint brace to lightweight wooden beams and columns constituting a wooden house.

[0005] Here, Patent Document 1 proposes a buckling-restrained brace suitable for use incorporated into the frame of wooden buildings, including wooden houses. Specifically, it is a buckling-restrained brace having a core material and a pair of restraining members arranged along both sides of the core material, in which the core material is made of steel and the pair of restraining members are made of wood, and laminated timber is applied to these restraining members, and the laminated timber has laminations stacked parallel to the core material. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 4901491 [Overview of the project] [Problems that the invention aims to solve]

[0007] Conventional buckling-restrained braces consist of a steel core surrounded by restraining plates, each made up of a pair of restraining plates facing the two wide surfaces of the core, and a pair of side plates connecting the ends of the restraining plates. However, these restraining plates and side plates each have their own unique cross-sectional shape and dimensions, and commonly available lumber cannot be used as is. As a result, the unit cost per unit area of ​​the restraining material is inevitably high, which often leads to high overall manufacturing costs for buckling-restrained braces.

[0008] This invention has been made in view of the above problems, and aims to provide a buckling-restrained brace that is suitable for use incorporated into the framework of wooden buildings and the like, and that can reduce manufacturing costs. [Means for solving the problem]

[0009] To achieve the above objective, one embodiment of the buckling-restrained brace according to the present invention is: A core material is formed by one first steel plate and two second steel plates joined perpendicularly to the wide surface of the first steel plate, and has a cross-shaped cross-section. The structure is characterized by having wooden shaft members that are arranged in four arrangement regions formed by the first steel plate and the second steel plate, extending in the longitudinal direction of the core material, and restraining members that are equipped with connecting means for connecting adjacent wooden shaft members to each other.

[0010] According to this embodiment, wooden battens extending in the longitudinal direction of the core are arranged in four arrangement regions of a core material with a cross-shaped cross section formed by the first steel plate and the second steel plate, and adjacent wooden battens are connected to each other by connecting means to form a restraining member. As a result, the wooden battens can be made of, for example, commonly available square timber that can be accommodated in one of the cross-shaped arrangement regions of the core material, thus resulting in a buckling-restrained brace with reduced manufacturing costs. Here, wooden members other than commonly available square timber may be used for the wooden battens.

[0011] Furthermore, since the restraint member is formed from four wooden shank members, the processing of the restraint member becomes easier. For example, the buckling restraint brace described in Patent Document 1 requires processing laminated timber to produce two L-shaped restraint members, and then connecting them with the core material sandwiched between them, with the two shank members inverted. In contrast, the buckling restraint brace of this embodiment has four wooden shank members arranged around a core material with a cross-shaped cross-section, and the buckling restraint brace is produced simultaneously when the restraint member is made by connecting the wooden shank members to each other. This makes the production of the buckling restraint brace even easier, and combined with the fact that the commonly available square timber can be used, the production cost of the buckling restraint brace can be reduced. Moreover, even if the wooden shank members are not made from commonly available square timber, this ease of production makes it possible to reduce production costs.

[0012] Furthermore, because the core material is surrounded by four wooden framing members, it becomes a buckling-restrained brace with excellent aesthetic design. Therefore, even when applied to the frame of a wooden building, there is no risk of it appearing inconsistent with the structural members.

[0013] Furthermore, other embodiments of the buckling-restrained brace according to the present invention include: The invention is characterized in that no spacer is interposed in the gap formed between adjacent wooden frame members and the end of the first steel plate or the end of the second steel plate.

[0014] According to this embodiment, even in a configuration where a gap is formed between adjacent wooden frame members and the end of the first or second steel plate, that is, in a configuration where the length of one side of a wooden frame member is longer than the length of one side of a core member with a cross-shaped cross-section, the wooden frame members are connected to each other by connecting means while their positions are defined in each of the four arrangement regions of the cross-shaped core member. Therefore, it becomes unnecessary to install spacers to prevent misalignment of the wooden frame members in the gap that is formed. Thus, eliminating the need for spacers, which are an essential component in conventional buckling-restrained braces, also contributes to reducing the manufacturing cost of buckling-restrained braces.

[0015] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The aforementioned wooden frame is formed from square timbers with a rectangular cross-section. The second steel plate is welded to the first steel plate. The wooden frame material is characterized in that the corners on the welded joint side of the first steel plate and the second steel plate are chamfered to form a means for preventing interference with the welded material.

[0016] In this embodiment, a second steel plate is welded to a first steel plate, and therefore there is weld reinforcement at the corners of both steel plates. The corners of the wooden frame, formed from rectangular (e.g., square) timbers, on the side with the weld reinforcement are chamfered. This chamfering forms a means to prevent interference with the weld reinforcement. As a result, the wooden frame, made from timbers, can be brought into smooth surface contact with both the first and second steel plates, and a buckling-restrained brace can be formed in which the core material is restrained by a restraining member that connects the four wooden frame members to each other with high strength. Here, it is preferable to use the timbers that are commonly available as described above.

[0017] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The connecting means is characterized in that it is a single first surface member straddling adjacent wooden shaft members and shaft-shaped fixing members for fixing the first surface member to each of the adjacent wooden shaft members.

[0018] According to this aspect, since the connecting means is a single first surface member straddling adjacent wooden shaft members and shaft-shaped fixing members for fixing the first surface member to each of the adjacent wooden shaft members, for example, by integrating adjacent wooden shaft members with a single long first surface member, good manufacturability can be enjoyed and high integrity of adjacent wooden shaft members can be obtained.

[0019] Here, examples of the first surface member include steel plates, inorganic board materials, fiber reinforced plastic surface materials, wooden surface materials, and the like. Examples of the shaft-shaped fixing members include nails and screws.

[0020] Also, in another aspect of the buckling restraint brace according to the present invention, The connecting means is characterized in that it is a plurality of second surface members straddling adjacent wooden shaft members and shaft-shaped fixing members for fixing the second surface members to each of the adjacent wooden shaft members.

[0021] According to this aspect, since the connecting means is a plurality of second surface members straddling adjacent wooden shaft members and shaft-shaped fixing members for fixing the second surface members to each of the adjacent wooden shaft members, for example, adjacent wooden shaft members can be connected using a plurality of piece-shaped second surface members, so that the generation of waste materials that may occur in the manufacturing process of the second surface members can be suppressed as much as possible. Examples of the planar shape of the second surface member include a rectangle and a triangle.

[0022] Also, in another aspect of the buckling restraint brace according to the present invention, The first surface member or the second surface member is a wooden surface member, and the restraining member is a wooden restraining member.

[0023] According to this aspect, since the first face material or the second face material is a wooden face material and the restraint material is a wooden restraint material, a buckling restraint brace excellent in appearance design can be formed. Further, by applying a wood screw to the axial fixing member, only wood is exposed to the outside, so that the buckling restraint brace is further excellent in appearance design. Incidentally, even when screws, bolts or the like are applied to the axial fixing member, the heads of the screws or the like can be buried inside the face material and the inlaid wood can be embedded in the surface so that the screws or the like cannot be visually recognized from the outside.

[0024] Further, in another aspect of the buckling restraint brace according to the present invention, the first face material or the second face material is a steel plate, and the restraint material is a hybrid restraint material made of the wooden shaft material and the steel plate.

[0025] According to this aspect, since the first face material or the second face material is a steel plate and the restraint material is a hybrid restraint material made of a wooden shaft material and a steel plate, a buckling restraint brace with extremely high restraint property of the core material can be formed. In this aspect, screws, nails, bolts or the like are applied to the axial fixing member.

[0026] Further, in another aspect of the buckling restraint brace according to the present invention, the connecting means is a tenon.

[0027] According to this embodiment, since the connecting means is a staple, a face material is not required, and adjacent wooden timbers can be connected using only staples, thereby further reducing the manufacturing cost of the buckling-restrained brace. Here, the staples may connect adjacent wooden timbers in a direction perpendicular to the longitudinal direction of the core material, and multiple staples may be arranged at intervals along the longitudinal direction. Alternatively, for example, multiple staples may be arranged in a V-shape or inverted V-shape along the longitudinal direction of the core material to form a staple truss. By forming a staple truss in this way, adjacent wooden timbers can be connected even more firmly, and the cross-sectional rigidity in two directions of the core material with a cross-shaped cross section in the restraining material can be increased. Furthermore, for example, if the thickness of the first steel plate and the second steel plate are the same and the overhang lengths of both are the same, there will be no strong axis direction and weak axis direction in the two directions (the direction along the first steel plate and the direction along the second steel plate) of the cross-shaped core material. However, for example, in configurations where the thickness of the second steel plate is relatively thinner than that of the first steel plate, or where the overhang length of the second steel plate is relatively shorter, the direction along the first steel plate will be the strong axis direction, and the direction along the second steel plate will be the weak axis direction.

[0028] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, Both the first steel plate and the second steel plate are characterized in that they have a narrow portion on the central side in the longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion on the end side in the longitudinal direction where the width of the wide surface is relatively wide.

[0029] In this embodiment, both the first and second steel plates have a narrow section with a relatively narrow width on the central side in their longitudinal direction, and a wide section with a relatively wide width on the end side in their longitudinal direction. This makes the narrow section on the central side a region that is easily plasticized, and furthermore, the plasticization region can be limited to the narrow section on the central side. In addition, since the boundary region between the wide section and the narrow section is a change region in which the planar area and cross-sectional area of ​​the core material change, the additional bending moment acting on the core material can be absorbed in this change region. An additional bending moment (or simply additional bending) is a bending moment that acts on the core material and the restraining member as a result of deformation, for example, when the frame and buckling-restrained brace deform significantly during a major earthquake. Thus, in this embodiment, it is possible to effectively absorb the additional bending moment acting on the core material in the boundary region between the wide section and the narrow section of the core material.

[0030] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The wooden frame is characterized in that at least one recess is provided at both ends of the wooden frame to form a gap between it and the second steel plate.

[0031] According to this embodiment, at least two recesses are provided at both ends of the wooden frame member to form a gap between them and the second steel plate. This allows the deformation of the core material to be absorbed by the gap, effectively suppressing the additional bending moment that acts on the ends of the wooden frame member constituting the restraining member due to the deformation of the core material. Here, "at least two recesses are provided to form a gap between them and the second steel plate" means that when the first steel plate is arranged in the in-plane direction of the structural plane and the second steel plate connected to it extends out of the plane of the structural plane, a recess is provided to form a gap between it and the second steel plate on which an additional bending moment may act. In addition, it also includes the possibility that two recesses are provided at both ends of the wooden frame member to form gaps between them and both the second steel plate and the first steel plate. [Effects of the Invention]

[0032] As can be understood from the above explanation, the buckling-restrained brace of the present invention is suitable for use incorporated into the framework of wooden buildings and the like, and provides a buckling-restrained brace that can reduce manufacturing costs. [Brief explanation of the drawing]

[0033] [Figure 1] This is a perspective view showing an example of a core material for forming a buckling-restrained brace according to the embodiment. [Figure 2A] This is a perspective view of an example of a restraint material forming a buckling-restrained brace according to the first embodiment. [Figure 2B] This is a perspective view of an example of a wooden frame. [Figure 3] This is a perspective view of an example of a buckling-restrained brace according to the first embodiment. [Figure 4] This is a perspective view of an example of a buckling-restrained brace according to the second embodiment. [Figure 5] This is a perspective view of an example of a buckling-restrained brace according to the third embodiment. [Figure 6] This figure shows the buckling-restrained brace according to the first embodiment incorporated into the frame of a wooden building or the like. [Figure 7] This figure illustrates the deformation patterns of the frame during a major earthquake and the additional bending moment at the buckling-restrained brace joints caused by the deformation of the frame. [Figure 8] This figure shows the overall buckling curve of the buckling-restrained brace. [Modes for carrying out the invention]

[0034] The buckling-restrained braces according to each embodiment will be described below with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0035] [Buckling-restrained brace according to the first embodiment] First, an example of a buckling-restrained brace according to the first embodiment will be described with reference to Figures 1 to 3. Here, Figure 1 is a perspective view showing an example of a core material forming a buckling-restrained brace according to the embodiment, Figure 2A is a perspective view of an example of a restraint material forming a buckling-restrained brace according to the first embodiment, and Figure 2B is a perspective view of an example of a wooden frame. Also, Figure 3 is a perspective view of an example of a buckling-restrained brace according to the first embodiment. Note that the core material 10 shown is common to all of the buckling-restrained braces 100, 100A, and 100B according to the first to third embodiments.

[0036] As shown in Figure 1, the core material 10 is formed by welding two second steel plates 12, similarly made of flat steel, to a first steel plate 11, which is made of a long, slender, plate-shaped flat steel, and the cross-section perpendicular to the longitudinal direction of the core material 10 is cross-shaped. By fillet welding the second steel plates 12 to the first steel plate 11, weld welding 15 is formed at the corners (joints) of both steel plates.

[0037] The first steel plate 11 has a narrow section 11A at the center in the longitudinal direction where the width of the wide surface is relatively narrow, and a wide section 11B at the end in the longitudinal direction where the width of the wide surface is relatively wide.

[0038] Similarly, the second steel plate 12 also has a narrow section 12A where the width of the wide surface is relatively narrow at the center in the longitudinal direction, and a wide section 12B where the width of the wide surface is relatively wide at the end in the longitudinal direction.

[0039] In the illustrated core material 10, the width t1 of the narrow portion 11A of the first steel plate 11 is set to be the same as the total width t1 of the narrow portions 12A of the two second steel plates 12 and the thickness of the first steel plate 11. Furthermore, the width t2 of the wide portion 11B of the first steel plate 11 is set to be the same as the total width t2 of the wide portions 12B of the two second steel plates 12 and the thickness of the first steel plate 11. In addition, the thickness of both the first steel plate 11 and the second steel plate 12 is set to be the same.

[0040] This configuration ensures that the core material 10, with its cross-shaped cross-section, has the same rigidity in the X and Y directions, thus forming a core material with equal rigidity in two orthogonal directions. Furthermore, within the core material 10 with its cross-shaped cross-section, four wooden framing members 21 (see Figures 2 and 3), which constitute the restraining member 20 described below, are each placed in one of the four arrangement regions A3 formed by the first steel plate 11 and the two second steel plates 12.

[0041] Here, for example, the thickness of the second steel plate 12 may be relatively thin, or the total width of the thicknesses of the two second steel plates 12 and the first steel plate 11 may be relatively narrower than the width of the first steel plate 11. In these configurations, the X direction is the strong axis direction, and the Y direction is the weak axis direction. In the illustrated example, both the first steel plate 11 and the second steel plate 12 have a stepped (single-stage) configuration in which the width widens in a tapered manner from the narrow sections 11A and 12A to the wide sections 11B and 12B, but they may also have a multi-stage configuration in which the width widens in two or more stages.

[0042] Both the first steel plate 11 and the second steel plate 12 have narrow sections 11A and 12A on the central side in the longitudinal direction and wide sections 11B and 12B on the end sides in the longitudinal direction. This makes it possible to make the regions A1 and A2 on the wide side of the narrow sections 11A and 12A on the central side more easily plastic, and furthermore, these easily plastic regions A1 and A2 can be limited to the regions on the wide side of the narrow sections 11A and 12A.

[0043] Furthermore, bolt holes 11a and 12a are provided in the wide portions 11B and 12B of both the first steel plate 11 and the second steel plate 12, respectively, for bolt connection via splice plates to gusset plates provided on the structural plane or fin stiffeners (see Figure 6) attached to the gusset plates, as will be explained below. When the buckling-restrained brace 100 is attached to the gusset plate such that the first steel plate 11 of the core material 10 is arranged parallel to the structural plane of the building, the core material 10 has a second steel plate 12 perpendicular to the first steel plate 11 which is parallel to the structural plane, thereby increasing the rigidity of the core material 10 in the direction outside the structural plane in addition to the rigidity in the direction inside the structural plane.

[0044] The first steel plate 11 and the second steel plate 12 forming the core material 10 are preferably made of steel with a low yield point, such as SN material (rolled steel for building structures) or LYP material (ultra-low yield point steel), which improves the seismic energy absorption due to yielding of the core material 10.

[0045] As shown in Figure 2A, the restraint member 20 is formed by four wooden frame members 21 with a square (or rectangular) cross-section, and four sets of connecting means 22 that connect adjacent wooden frame members 21 across gaps G1 and G2, where the first steel plate 11 and the second steel plate 12 that constitute the core material 10 shown in Figure 1 are arranged.

[0046] Here, the wooden frame 21 is formed from commonly available lumber, and examples include lumber with a square cross-section of 105mm (105mm square) or 120mm (120mm square), made from solid wood such as cedar or pine, or laminated lumber with laminated laminas. The length of the lumber 21 can be set to approximately 3m, for example, depending on the length of the core material 10.

[0047] Of the rectangular timber 21, the corners on the welded joint side of the first steel plate 11 and the second steel plate 12 are chamfered, and this chamfer 21a forms a means to prevent interference with the weld reinforcement 15.

[0048] Furthermore, as shown in Figure 2B, recesses 21b of a certain length t5 in the longitudinal direction are provided at both ends of the square members 21. In the buckling-restrained brace 100 (see Figure 3) in which the core member 10 and the restraining member 20 are assembled, a gap G4 is formed between the second steel plate 12 constituting the core member 10 and the ends of each square member 21 by the recesses 21b. When the buckling-restrained brace 1100 is installed on the structural plane, if the first steel plate 11 of the core member 10 is positioned in the in-plane direction of the structural plane and the second steel plate 12 is positioned to protrude out of the structural plane, the gap G4 provided at both ends of each square member 21 between the second steel plate 12 protruding out of the structural plane allows the deformation of the core member 10 during an earthquake to be absorbed by the gap G4, and it is possible to suppress the additional bending moment acting on the ends of the square members 21 due to the deformation of the core member 10. For this reason, the length of the recesses 21b is set to a length over which an additional bending moment can act. Furthermore, in addition to the recesses 21b provided on the second steel plate 12 side at both ends of the square timber 21, additional recesses may also be provided on the first steel plate 11 side.

[0049] The connecting means 22 is formed by a long first facing material 23 that surrounds almost the entire area of ​​each side of two adjacent wooden shafts 21, and a plurality of axial fixing members 24 that fix the first facing material 23 to each wooden shaft 21.

[0050] Here, the first facing material 23 can be steel plate, inorganic board material (cement board, gypsum board, calcium silicate board, etc.), fiber-reinforced plastic facing material such as CFRP (Carbon Fiber Reinforced Plastics) and GFRP (Glass Fiber Reinforced Plastic), or wood facing material such as plywood, CLT (Cross Laminated Timber) panel, or LVL (Laminated Veneer Lumber). By applying wood facing material, a buckling-restrained brace with excellent aesthetic design can be formed. Furthermore, by applying steel plate, a buckling-restrained brace with extremely high restraint of the core material 10 can be formed.

[0051] When a wood-based panel is applied to the first panel 23, the restraint member 20 becomes a wooden restraint member. On the other hand, when a steel plate is applied to the first panel 23, the restraint member 20 becomes a hybrid restraint member formed from a wooden frame and a steel plate.

[0052] Nails, screws, bolts (including wood screws), and bolts (including lag screw bolts) can be used for the axial fixing member 24. However, when a wooden panel is used for the first panel 23, wood screws can be used for the axial fixing member 24, resulting in only wood being exposed to the outside, thus creating a buckling-restrained brace with even better aesthetic appeal. On the other hand, when a steel plate is used for the first panel 23, nails, screws, bolts, and other fasteners can be used for the axial fixing member 24.

[0053] In practice, wooden shaft members 21 are placed in each of the four arrangement regions A3 of the core material 10 shown in Figure 1, and first facing members 23 are placed so as to straddle adjacent wooden shaft members 21. By fixing the first facing members 23 to both wooden shaft members 21 with multiple axial fixing members 24, a restraining member 20 is formed in which the four wooden shaft members 21 are interconnected by the four first facing members 23. At the same time that the restraining member 20 is formed around the core material 10, the buckling-restrained brace 100 shown in Figure 3 is formed.

[0054] Since the connecting means 22 consists of a single first surface material 23 that spans adjacent wooden frame members 21 and an axial fixing member 24 that fixes the first surface material 23 to each of the adjacent wooden frame members 21, the adjacent wooden frame members 21 can be integrated using a single long first surface material 23, thereby enjoying good manufacturability and forming a highly integrated restraining material 20 between adjacent wooden frame members 21.

[0055] In the buckling-restrained brace 100, the wooden shaft members 21 of the restraining member 20 protrude laterally beyond the end faces of the narrow sections 11A and 12A of the first steel plate 11 and second steel plate 12 of the core material 10. Therefore, a gap G3 is formed between adjacent wooden shaft members 21, the end faces of the narrow sections 11A and 12A, and the first face material 23. However, since the wooden shaft members 21 are connected to each other by the first face material 23 with their positions defined in the four arrangement regions A3 of the cross-shaped core material 10, it becomes unnecessary to install spacers to prevent displacement of the wooden shaft members 21 in the formed gap G3. In this way, the spacers, which are an essential component in conventional buckling-restrained braces, can be made unnecessary, thus reducing the manufacturing cost of the buckling-restrained brace.

[0056] Furthermore, by using commonly available square timbers 21 that can be accommodated in each of the four cross-shaped arrangement regions A3 of the core material 10 as the wooden timbers 21 that form the restraint members 20 of the buckling-restrained brace, the material cost of the restraint members 20 can be reduced, which also contributes to reducing the manufacturing cost of the buckling-restrained brace 100.

[0057] Furthermore, since the restraint member 20 has a simple structure, consisting of four wooden shaft members 21 and connecting means 22 that connect them, it is easy to manufacture the restraint member 20, which also contributes to reducing the manufacturing cost of the buckling-restrained brace 100.

[0058] Furthermore, in a configuration where the first facing material 23 is made of steel plate and screws, nails, bolts, etc. are applied to the axial fixing member 24, a buckling-restrained brace 100 with extremely high restraint on the core material 10 is formed. On the other hand, in a configuration where the first facing material 23 is made of wood and wood screws are applied to the axial fixing member 24, the restraining material 20 is made entirely of wood, resulting in a wooden restraining material, and thus a buckling-restrained brace 100 with excellent aesthetic design is formed.

[0059] [Buckling-restrained brace according to the second embodiment] Next, an example of a buckling-restrained brace according to the second embodiment will be described with reference to Figure 4. Here, Figure 4 is a perspective view of an example of a buckling-restrained brace according to the second embodiment.

[0060] The buckling-restrained brace 100A differs from the buckling-restrained brace 100 in that it is equipped with a restraining member 20A.

[0061] The connecting means 25 that forms the restraint member 20A includes a plurality of second facing members 26 that straddle adjacent wooden frame members 21, and axial fixing members 27 that fix the second facing members 26 to each of the adjacent wooden frame members 21. The second facing members 26 can also be made of steel plates, inorganic board materials, fiber-reinforced plastic facing members, wood facing members, etc., but by using wood facing members for the second facing members 26, a buckling-restrained brace with excellent appearance and design can be formed. Furthermore, in the configuration in which wood facing members are used for the second facing members 26, the restraint member 20A becomes a wooden restraint member formed entirely of wood. On the other hand, in the configuration in which steel plates are used for the second facing members 26, a buckling-restrained brace with extremely high restraint of the core member 10 can be formed.

[0062] The second facing material 26 has trapezoidal facing material pieces at both ends and a triangular facing material piece in the center, and each facing material piece is arranged such that the tops or vertices of adjacent facing material pieces 26 are in a relative vertical position to each other. With this arrangement configuration, multiple second facing material pieces 26 are arranged over almost the entire side surface of adjacent wooden frame members 21, and each second facing material 26 is fixed to both wooden frame members 21 by axial fixing members 27, thereby forming a highly integrated restraining material 20A between adjacent wooden frame members 21.

[0063] Furthermore, by using multiple piece-shaped second facing materials 26 to connect adjacent wooden frame materials 21, the generation of waste materials that may occur during the manufacturing process of the second facing materials 26 can be suppressed as much as possible.

[0064] [Buckling-restrained brace according to the third embodiment] Next, an example of a buckling-restrained brace according to the third embodiment will be described with reference to Figure 5. Here, Figure 5 is a perspective view of an example of a buckling-restrained brace according to the third embodiment.

[0065] The buckling-restrained brace 100B differs from the buckling-restrained braces 100 and 100A in that it is equipped with a restraining member 20B.

[0066] The connecting means 28 that form the restraining member 20B are a plurality of staples. In the illustrated example, the plurality of staples 28 are arranged at intervals along the longitudinal direction of the wooden frame 21, but for example, the plurality of staples may be arranged in a V-shape or inverted V-shape along the longitudinal direction of the wooden frame 21 to form a staple truss.

[0067] Since the connecting means 28 that form the restraining member 20B are staples, a face material is not required as a component of the connecting means, which further reduces the manufacturing cost of the buckling-restrained brace.

[0068] [Example of applying buckling-restrained braces to a structural frame] Next, with reference to Figures 6 to 8, examples of the application of buckling-restrained braces to a frame will be described. Here, Figure 6 shows the buckling-restrained brace according to the first embodiment incorporated into the frame of a wooden building or the like. Figure 7 is a diagram illustrating the deformation of the frame during a major earthquake and the additional bending moment at the buckling-restrained brace joint caused by the deformation of the frame. Note that the buckling-restrained brace in the illustrated example may be incorporated into frames of steel (S) buildings, reinforced concrete (RC) buildings, and steel-reinforced concrete (SRC) buildings, in addition to wooden building frames. Furthermore, the buckling-restrained brace 100A according to the second embodiment and the buckling-restrained brace 100B according to the third embodiment may be applied to the frame.

[0069] The frame S shown in Figure 6 is formed by wooden columns C and beams B that make up a wooden building. Gusset plates GP made of flat steel are attached to the two diagonal corners. Fin stiffeners FS are welded to the surface of the gusset plates GP so as to be perpendicular to the surface. The fin stiffeners FS are joined to the gusset plates GP such that their center L3 intersects the intersection point O of the column center L1 of column C and the beam center L2 of beam B. The buckling-restrained braces 100 are also arranged linearly, passing through the intersection points O of both diagonally opposite positions.

[0070] The gusset plate GP and the first steel plate 11 of the core material 10 are joined by high-tension bolts via a splice plate SP, and the fin stiffener FS and the second steel plate 12 of the core material 10 are joined by high-tension bolts via a splice plate SP.

[0071] As shown in Figure 7, during a major earthquake, the structural plane deforms, and in the buckling-restrained brace joint, an additional bending moment shown in equation (1) below may act, assuming the joint is rigid.

[0072]

number

[0073] With the buckling-restrained brace 100, the core material 10, which has a cross-shaped cross-section, is surrounded by a restraining member 20 equipped with four wooden shaft members 21. This increases the rigidity of the frame S in both the in-plane and out-plane directions, making it possible to form a frame S with a high deformation suppression effect.

[0074] <Consideration of overall buckling> Next, we will explain a design method for preventing overall buckling of a buckling-restrained brace.

[0075] In designing buckling-restrained braces, the following equation (2) should be satisfied so that overall buckling of the buckling-restrained brace does not occur.

[0076]

number

[0077] Here, the bending moment acting at the center of the wooden frame can be expressed by the following equation (3).

[0078]

number

[0079] The condition for preventing overall buckling of the restraint material is that the following equation (4) is satisfied.

[0080]

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[0081] Equation (4) is shown in Figure 8 as the overall buckling curve of the buckling-restrained brace. In Figure 8, the area above the overall buckling curve is the safety zone, and the area below is the danger zone. The design axial force of the restraining material, the Euler load, the length of the general part of the core material, and the yield bending strength of the restraining material are set so that they fall within the safety zone. Note that the overall buckling curve of the buckling-restrained brace shown in Figure 8 is valid for both overall buckling in the weak axis direction and overall buckling in the strong axis direction of the core material in a configuration in which the core material has a strong axis direction and a weak axis direction.

[0082] In addition to checking the relationship between the yield bending strength of the restraining material and the bending moment acting on it, it is also advisable to check that the short-term allowable bending strength of the restraining material is greater than the bending moment acting on it when the core material yields (formulas omitted).

[0083] <Investigation of indentation failure of wooden frame materials> Next, we will explain the method for examining the failure of the wooden frame due to the core material embedding into it. In order to prevent the wooden frame from failing due to the core material embedding into it, we must verify that the following equation (5) is satisfied.

[0084]

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[0085] In addition to examining the relationship between the indentation resistance of the wooden frame and the bracing force acting on it, it is also advisable to examine whether the short-term allowable indentation resistance of the wooden frame is greater than the bracing force acting at the time of core material yielding (formulas omitted).

[0086] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0087] 10: Core material 11: 1st steel plate 11A: Narrow width part 11B: Wide section 11a: Bolt hole 12:Second steel plate 12A: Narrow part 12B: Wide section 12a: Bolt hole 15: Welding excess 20, 20A, 20B: Retaining material 21: Wooden timber (square timber) 21a: Chamfering (means to prevent interference) 21b: Recess 22: Connecting means 23: First facing material 24: Wood screw (shaft-shaped fixing member) 25: Connecting means 26: Second facing material (facing material piece) 27: Wood screw (shaft-shaped fixing member) 28: A means of connection 100, 100A, 100B: Buckling-restrained brace G1, G2, G3, G4: Gap A1, A2: Regions that are easily plasticized (regions that absorb additional bending) A3: Placement area S: Frame (composition) C: Pillar B: Beam GP: Gusset Plate FS: Finstiffna SP: Splice Plate

Claims

1. A core material is formed by one first steel plate and two second steel plates joined perpendicularly to the wide surface of the first steel plate, and has a cross-shaped cross-section. The structure comprises four wooden shaft members, each positioned in one of the four arrangement regions formed by the first steel plate and the second steel plate, extending in the longitudinal direction of the core material, and a restraining member equipped with connecting means for connecting adjacent wooden shaft members. A buckling-restrained brace characterized in that a gap equivalent to the thickness of the first or second steel plate is interposed between each adjacent wooden frame member, and the wooden frame members are connected to each other across the gap by the connecting means.

2. The buckling-restrained brace according to claim 1, characterized in that no spacer is interposed in the gap formed by the adjacent wooden frame members and the end of the first steel plate or the end of the second steel plate.

3. The aforementioned wooden frame is formed from square timbers with a rectangular cross-section. The second steel plate is welded to the first steel plate. The buckling-restrained brace according to claim 1 or 2, characterized in that the corner portion of the wooden frame material on the welded joint side of the first steel plate and the second steel plate is chamfered to form a means for preventing interference with the welded material.

4. The buckling-restrained brace according to claim 1, characterized in that the connecting means comprises a first surface material that spans adjacent wooden frame materials and an axial fixing member that fixes the first surface material to each of the adjacent wooden frame materials.

5. The buckling-restrained brace according to claim 1, characterized in that the connecting means comprises a plurality of second facing members that straddle adjacent wooden stiles, and axial fixing members that fix the second facing members to each of the adjacent wooden stiles.

6. The buckling-restrained brace according to claim 4, characterized in that the first facing material is a wood facing material and the restraining material is a wooden restraining material.

7. The buckling-restrained brace according to claim 5, characterized in that the second facing material is a wood facing material and the restraining material is a wooden restraining material.

8. The buckling-restrained brace according to claim 4, characterized in that the first facing material is a steel plate, and the restraining material is a hybrid restraining material made of the wooden frame and the steel plate.

9. The buckling-restrained brace according to claim 5, characterized in that the second facing material is a steel plate, and the restraining material is a hybrid restraining material made of the wooden frame and the steel plate.

10. The buckling-restrained brace according to claim 1 or 2, characterized in that the connecting means is a staple.

11. The buckling-restrained brace according to claim 1 or 2, characterized in that both the first steel plate and the second steel plate have a narrow portion on the longitudinal central side where the width of the wide surface is relatively narrow, and a wide portion on the longitudinal end side where the width of the wide surface is relatively wide.

12. The buckling-restrained brace according to claim 1 or 2, characterized in that recesses are provided at least at both ends of the wooden frame member to form a gap between it and the second steel plate.

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