Buckling-restrained brace

Abstract

To provide a buckling-restrained brace that can reduce friction between the end face of a narrow-width part of the core material and a spacer, which prevents damages to the wooden restraint due to localized strong-axis buckling in the core material.SOLUTION: A buckling-restrained brace 100 has a plate-shaped core material 10 made of steel and a wooden restraint 20 formed by a pair of wooden restraints 30 arranged facing two wide faces 11a of the core material 10 and a pair of side plates 40 connecting the pair of restraints 30. A first gap G1 is provided between an end face 11b of a narrow-width part 11 of the core material 10 and the side plates 40, a steel spacer 15 is interposed in the first gap G1, and friction reducing means 18 is provided between the spacer 15 and the narrow-width part 11 to reduce the friction force between them.SELECTED DRAWING: Figure 1

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 the periphery of a steel core material is braced only with steel plates, a form in which the periphery of a steel core material is braced with RC (Reinforced Concrete), and a form in which the periphery of 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 performance 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 bracing materials will coexist, resulting in an unbalanced appearance.

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

[0005] Here, Patent Document 1 proposes a buckling restraint brace suitable for being incorporated and used within the framework of wooden buildings including wooden houses. Specifically, it is a buckling restraint brace having a core material and a pair of restraint materials arranged along both sides of the core material. The core material is formed of steel, the pair of restraint materials are formed of wood, and laminated veneer lumber is applied to these restraint materials, and the laminated veneer lumber is a structure in which laminas are laminated parallel to the core material.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] According to the buckling restraint brace described in Patent Document 1, by means of a pair of restraint materials formed of wood, it is possible to improve the strength against overall buckling of the buckling restraint brace.

[0008] By the way, the core material of the buckling restraint brace may be in a form having a narrow-width portion where the width of the wide-width surface is relatively narrow on the central side in the longitudinal direction thereof, and a wide-width portion where the width of the wide-width surface is relatively wide on the end side in the longitudinal direction thereof. According to this form, the narrow-width portion on the central side can be made into a region where plasticization is easy, and the effect that the plasticization region can be limited to the narrow-width portion on the central side is achieved. And since a gap naturally forms between the end face of the narrow-width portion of the core material and the wooden restraint material or side plate, by disposing a steel spacer in this gap, displacement of the core material in the gap direction is suppressed.

[0009] During an earthquake, a buckling restraint brace causes higher-order buckling in the weak-axis direction or the strong-axis direction over the entire narrow-width portion of the steel core material to absorb seismic energy. However, if there is locally significant friction between the end face of the steel core material and the steel spacer, local buckling in the strong-axis direction may occur due to this friction, and excessive indentation may occur in the wooden restraint body such as the side plate due to the local buckling in the strong-axis direction of the core material, raising concerns about damage. Therefore, it is crucial to reduce the friction between the end face of the narrow-width portion of the core material and the spacer. However, Patent Document 1 does not disclose any means for reducing such friction between the end face of the narrow-width portion of the core material and the spacer.

[0010] The present invention has been made in view of the above problems, and an object thereof is to provide a buckling restraint brace that can reduce the friction between the end face of the narrow-width portion of the core material and the spacer and suppress damage to the wooden restraint body due to local buckling in the strong-axis direction of the core material.

Means for Solving the Problems

[0011] To achieve the above object, one aspect of the buckling restraint brace according to the present invention is a steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members disposed to face the two wide-width surfaces of the core material and a pair of side plates connecting the pair of restraint members, the core material includes a narrow-width portion where the width of the wide-width surface is relatively narrow on the central side in the longitudinal direction thereof, and a wide-width portion where the width of the wide-width surface is relatively wide on the end side in the longitudinal direction thereof, a first gap is provided between the end face of the narrow-width portion of the core material and the side plate, and a steel spacer is interposed in the first gap, characterized in that friction reduction means for reducing the frictional force between the spacer and the narrow-width portion is provided.

[0012] According to this aspect, in a form where a steel spacer is interposed in a first gap between an end face of a narrow-width portion of a core material and a side plate, friction reducing means for reducing the frictional force between the spacer and the narrow-width portion is provided, so that local buckling in the strong axis direction occurs in the core material due to the frictional force, and it is possible to suppress breakage of the side plate in particular of the wooden restraint due to the local buckling.

[0013] Further, since the wooden restraint has a pair of restraint members and a pair of wooden side plates that connect the corresponding ends of the pair of restraint members, the core material can be surrounded by a wooden restraint having a strong closed structure. Here, the wooden restraint members and the side plates can be connected by an adhesive, nails, screws, bolts, or a plurality of these. Furthermore, since the core material is surrounded by the wooden restraint, it becomes a buckling restraint brace with excellent appearance design, so even when applied to the structure of a wooden building, there is no risk of giving a mismatched appearance to the structural components.

[0014] Another aspect of the buckling restraint brace according to the present invention is a steel plate-shaped core material, a wooden restraint formed by a pair of wooden restraint members arranged to face two wide-width surfaces of the core material and having a U-shaped or L-shaped cross section, the core material includes a narrow-width portion where the width of the wide-width surface is relatively narrow on the central side in the longitudinal direction, and a wide-width portion where the width of the wide-width surface is relatively wide on the end side in the longitudinal direction, a first gap is provided between an end face of the narrow-width portion of the core material and the restraint member, and a steel spacer is interposed in the first gap, characterized in that friction reducing means for reducing the frictional force between the spacer and the narrow-width portion is provided.

[0015] According to this aspect, in a form where a steel spacer is interposed in a first gap between an end face of a narrow portion of a core material and a restraint member having a U-shaped or L-shaped cross-sectional shape, a friction reduction means for reducing the frictional force between the spacer and the narrow portion is provided, so that local buckling in the strong axis direction occurs in the core material due to the frictional force, and it is possible to suppress damage to a portion of the wooden restraint member that faces the end face of the core material, particularly in the restraint member.

[0016] Further, since the wooden restraint member has a pair of restraint members with a U-shaped or L-shaped cross-sectional shape, the core material can be surrounded by a wooden restraint member having a strong closed structure. Furthermore, since the core material is surrounded by the wooden restraint member, it becomes a buckling restraint brace with excellent aesthetic design. Therefore, even when applied to the structure of a wooden building, there is no risk of giving an unbalanced appearance to the structural components.

[0017] Another aspect of the buckling restraint brace according to the present invention is The friction reduction means is characterized in that it is a curved or tapered end face that protrudes toward the other side on at least one of the spacer or the narrow portion.

[0018] According to this aspect, since the friction reduction means is a curved or tapered end face that protrudes toward the other side on at least one of the spacer or the narrow portion, the frictional force between the spacer and the narrow portion can be effectively reduced only by processing the end face of the spacer or the like. Here, "at least one of the spacer or the narrow portion" includes both a form in which one end face of the spacer and the narrow portion is a curved or tapered end face that protrudes toward the other side and a form in which both end faces of the spacer and the narrow portion are curved or tapered end faces that protrude toward the other side.

[0019] Another aspect of the buckling restraint brace according to the present invention is The friction reduction means is an axially shaped steel material that is interposed between the spacer and the narrow portion and has a curved surface or a tapered surface that protrudes toward the other side from at least one of the spacer or the narrow portion.

[0020] According to this aspect, the friction reducing means is an axially-shaped steel material having a convex curved surface or a tapered surface that intervenes between the spacer and the narrow portion and protrudes from at least one of the spacer or the narrow portion toward the other side. By simply disposing the axially-shaped steel material with a simple structure between the spacer and the narrow portion, the frictional force between the spacer and the narrow portion can be effectively reduced. Here, "protruding from at least one of the spacer or the narrow portion toward the other side" includes both a form in which the curved or tapered end surface of one axially-shaped steel material is disposed with the other side facing it, and a form in which the curved or tapered end surfaces of two axially-shaped steel materials are disposed with the other side facing it. Further, the axially-shaped steel material may be simply disposed between the spacer and the narrow portion, or may be fixed to the spacer or the narrow portion by welding or the like. Among these, fixing the axially-shaped steel material to the spacer by welding is preferable because it can prevent stress from occurring during welding in the core material when welding the axially-shaped steel material to the core material, and can prevent displacement of both the spacer and the axially-shaped steel material.

[0021] Another aspect of the buckling restraint brace according to the present invention is characterized in that the friction reducing means is any one of round steel, wire mesh, wooden board, or butyl rubber that intervenes between the spacer and the narrow portion.

[0022] According to this aspect, since the friction reducing means is any one of round steel, wire mesh, wooden board, or butyl rubber that intervenes between the spacer and the narrow portion, a commercially available and inexpensive member can be applied to effectively reduce the frictional force between the spacer and the narrow portion. For example, round steel and wire mesh can be welded to the spacer, and wooden boards and butyl rubber can be adhered to either the spacer or the core material.

[0023] Another aspect of the buckling restraint brace according to the present invention is characterized in that a second gap is further provided between the end surface of the wide portion and the side plate or the restraint material.

[0024] According to the present embodiment, a second gap is further provided between the end face of the wide portion of the core material and the side panel or restraint material. Therefore, when the frame in which the buckling restraint brace is incorporated and the buckling restraint brace are deformed within the structural plane, contact between the end face of the wide portion of the core material and the side panel or restraint material is eliminated or reduced, making it possible to suppress cracks that may occur in the side panel or restraint material due to this contact.

[0025] Another aspect of the buckling restraint brace according to the present invention is A reinforcing rib is joined to the wide surface of the wide portion so as to be perpendicular to the wide surface, and the wide surface has a cross-shaped cross section. the restraint member has a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, The reinforcing rib is accommodated in the slit with a third gap therebetween.

[0026] According to this aspect, the reinforcing ribs perpendicular to the wide surface of the core material are joined to form a cross-shaped cross section, so that when the buckling restrained brace is attached to the gusset plate with the wide surface of the core material arranged parallel to the structural surface of the building, the core material has reinforcing ribs perpendicular to the wide surface parallel to the structural surface, so that the rigidity of the end of the core material in the direction outward from the structural surface can be increased. In the gusset plate of the structural surface to which the core material with a cross-shaped cross section is attached, fin stiffeners are attached to the gusset plate, and the core material and gusset plate, and the reinforcing ribs and fin stiffeners of the buckling restrained brace are each joined by high tension bolts or the like via splice plates.

[0027] Furthermore, a slit is provided in the restraining material at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, and the reinforcing rib is accommodated in the slit with a third gap therebetween. This prevents the reinforcing rib from coming into contact with and being pressed against the restraining material when the frame and buckling restraint brace deform, thereby preventing damage to the restraining material. Effect of the Invention

[0028] As can be understood from the above description, according to the buckling restraint brace of the present invention, the friction between the end face of the narrow-width portion of the core material and the spacer is reduced, and damage to the wooden restraint body due to local buckling in the strong axis direction of the core material can be suppressed.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0030] Hereinafter, the buckling restraint brace according to the embodiment will be described with reference to the attached drawings. In the present specification and drawings, substantially the same components may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0031] [Buckling Restraint Brace According to Embodiment] First, with reference to FIGS. 1 to 6, an example of the buckling restraint brace according to the embodiment will be described. Here, FIG. 1 is a perspective view showing an example of a core material forming the buckling restraint brace according to the embodiment together with an example of friction reduction means and a spacer. FIGS. 2A and 2B are both perspective views showing another example of the friction reduction means together with the spacer. Further, FIG. 3 is a perspective view of an example of the buckling restraint brace according to the embodiment, and FIGS. 4 and 5 are respectively a view taken along the line IV-IV and a view taken along the line V-V of FIG. 3.

[0032] As shown in FIG. 1, the core material 10 is formed of an elongated plate-shaped flat steel, and has a narrow-width portion 11 where the width t1 of the wide-width surface 11a is relatively narrow on the central side in the longitudinal direction, and a wide-width portion 12 where the width t2 of the wide-width surface 12a is relatively wide on the end side in the longitudinal direction. Further, a reinforcing rib 13 orthogonal to the wide-width surface 12a is joined to the wide-width surface 12a of the wide-width portion 12 by welding to exhibit a cross-sectional cruciform shape.

[0033] The wide-width portion 12 has a width-increasing portion 12' where the width gradually increases in a tapered shape from the narrow-width portion 11. Here, the illustrated example has a form with a single-stage width-increasing portion 12', but it may have a form with two or more stages of width-increasing portions and the width may increase in a multi-stage shape.

[0034] The core material 10 is preferably formed of a steel material with a low yield point such as SN material (rolled steel for building structures) or LYP material (extra low yield point steel material), and the earthquake energy absorption property due to the yield of the core material 10 becomes good.

[0035] Since the core material 10 has a narrow-width portion 11 on the central side in its longitudinal direction and a wide-width portion 12 on the end side in the longitudinal direction, among the narrow-width portions 11 located on the central side, a region where the narrow-width portion 11 is easily plasticized can be formed. In the entire area of the narrow-width portion 11, buckling (higher-order buckling) in the weak-axis direction occurs on the wide surface 11a, and buckling (higher-order buckling) in the strong-axis direction occurs on the end surface 11b, thereby absorbing seismic energy.

[0036] Also, bolt holes 12c and 13a for bolt connection via a splice plate are provided in the wide-width portion 12 and the reinforcing rib 13, respectively, to be bolted to a gusset plate provided on the structural surface or a fin stiffener (see FIG. 7) attached to the gusset plate, as described below.

[0037] When the buckling restraint brace 100 is attached to the gusset plate such that the wide surfaces 11a and 12a of the core material 10 are arranged parallel to the structural surface of the building, by having the reinforcing rib 13 orthogonal to the wide surfaces 11a and 12a parallel to the structural surface in the core material 10, the rigidity in the out-of-plane direction can be increased at the end of the core material 10.

[0038] On the side of the narrow-width portion 11, a first gap G1 is formed due to the difference in width between the narrow-width portion 11 and the wide-width portion 12. Steel spacers 15 are arranged in the respective first gaps G1 on the two sides of the narrow-width portion 11.

[0039] On one first end surface 15a (the first end surface 15a on the core material side) along the longitudinal direction of the spacer 15, friction reduction means 18 (an example of a shaft-shaped steel material) formed of round steel is fixed by welding. That is, on the first end surface 15a of the spacer 15, the round steel 18 becomes a shaft-shaped steel material having a convex curved surface or a tapered surface protruding toward the core material side. Here, instead of round steel, a wire mesh may be applied as the friction reduction means 18.

[0040] Further, among the spacers 15, a tapered surface 15c is provided on the second end surface 15b which is the longitudinal end portion. Due to this tapered surface 15c, when an axial force is generated in the core material 10 causing it to expand and contract, contact between the second end surface 15b of the spacer 15 and the width increasing portion 12' of the wide width portion 12 of the core material 10 can be suppressed.

[0041] In a buckling restraint brace 100 in which a steel spacer 15 is interposed in a first gap G1 between an end surface 11b of a narrow width portion 11 of a core material 10 and a side plate 40 (see FIG. 3) forming a wooden restraint body 20, friction reducing means 18 for reducing the frictional force between the spacer 15 and the end surface 11b of the narrow width portion 11 of the core material 10 is provided. As a result, local buckling in the strong axis direction (not buckling occurring over the entire area of the narrow width portion 11 but local buckling) occurs in the narrow width portion 11 of the core material 10 due to the frictional force, and damage to the side plate 40 in particular of the wooden restraint body 20 due to the local buckling can be suppressed. This will be described in detail below.

[0042] As friction reducing means provided on the first end surface 15a of the spacer 15, in addition to the round steel 18 shown in FIG. 1, there are also the forms shown in FIGS. 2A and 2B.

[0043] The friction reducing means 18A shown in FIG. 2A is an axially shaped steel material with a triangular cross-sectional shape perpendicular to the longitudinal direction, and is an axially shaped steel material having a tapered surface convex toward the core material side. The axially shaped steel material 18A is fixed to the first end surface 15a of the spacer 15 by welding.

[0044] On the other hand, the friction reducing means 18B shown in FIG. 2B is a form in which the first end surface 15a of the spacer 15A is formed into a curved end surface convex toward the core material side.

[0045] Thus, there are various forms of means for reducing the frictional force between the steel spacer 15 and the end face 11b of the narrow-width portion 11 of the core material 10. These may be arranged between the spacer 15 and the end face 11b of the narrow-width portion 11 without being fixed by welding as in the illustrated example. Further, instead of the steel shaft-like steel materials 18, 18A, wooden boards, butyl rubber, etc. may be applied as the friction-reducing means. Further, instead of the curved end face 18B, the first end face 15a of the spacer may be formed as a tapered end face convex toward the core material side. Furthermore, on both the first end face 15a of the spacer 15 and the end face 11b of the narrow-width portion 11 of the core material 10, a curved or tapered shaft-like steel material convex toward the other side may be fixed, or a curved or tapered end face convex toward the other side may be formed.

[0046] As shown in FIG. 3, a pair of wooden restraint members 30 are arranged so as to face the two wide-width surfaces 11a of the core material 10. By connecting the ends of the pair of restraint members 30 with a pair of wooden side plates 40, a wooden restraint body 20 is formed, and a buckling restraint brace 100 is formed in which the region of the core material 10 from the narrow-width portion 11 to the middle of the width-increasing portion 12' of the wide-width portion 12 is surrounded by the wooden restraint body 20.

[0047] Here, the connection between the restraint member 30 and the side plate 40 is performed by any one or a plurality of types of adhesives, nails, screws, bolts.

[0048] The wooden restraint body 20 in the illustrated example is formed by a pair of wooden restraint members 30 and a pair of side plates 40 connecting the pair of restraint members 30. However, the wooden restraint body may also be formed by a pair of wooden restraint members having a U-shaped or L-shaped cross-sectional shape (not shown).

[0049] Slits 35 are provided at the longitudinal ends of the restraint member 20, and a part of the reinforcing rib 13 joined to the end of the core material 10 is loosely fitted in the slits 35 in a state having a third gap G3, thereby preventing interference between the restraint member 30 and the reinforcing rib 13.

[0050] The restraint member 30 is a laminated wood formed by laminating and bonding a plurality of laminas. As will be described in detail below, the cross-sectional area, cross-sectional rigidity, Young's modulus, etc. of the wooden restraint body 20 are set so as to prevent the overall buckling of the buckling restraint brace. And this Young's modulus is determined by the material of the wood. Examples of the wood material include cypress, red pine, larch, fir, and spruce. On the other hand, the side plate 40 is formed of, for example, a solid wood material.

[0051] As shown in FIG. 4, a second gap G2 with a predetermined width is provided between the wide-width portion 12 (width-increasing portion 12') of the core material 10 and the side plate 40, and a third gap G3 with the above-mentioned predetermined width is provided between the slit 35 and the reinforcing rib 13.

[0052] In this way, since the second gap G2 is provided between the end face 12b of the wide-width portion 12 and the side plate 40, when the buckling restraint brace 100 is incorporated into the structure and the buckling restraint brace 100 deforms in the plane, the contact between the end face 12b of the wide-width portion 12 and the side plate 40 is eliminated or relaxed, and it becomes possible to suppress cracks that may occur in the side plate 40 due to this contact.

[0053] Furthermore, in the restraint member 30, a slit 35 that does not interfere with the reinforcing rib 13 is provided at a position corresponding to the reinforcing rib 13, and since the reinforcing rib 13 is accommodated in a state having the third gap G3 with respect to the slit 35, when the structure and the buckling restraint brace 100 deform, it is possible to suppress the reinforcing rib 13 from contacting and pressing the restraint member 30 and damaging the restraint member 30.

[0054] Also, as shown in FIG. 5, a round steel 18 fixed to the first end face 15a of a spacer 15 disposed in the first gap G1 between the end face 11b of the narrow-width portion 11 of the core material 10 and the side plate 40 is in line contact, and the generation of frictional force between the end face 11b of the narrow-width portion 11 and the spacer 15 is suppressed or inhibited, and the core material 10 is in a state where displacement toward the side plate 40 is prevented.

[0055] As shown in FIG. 6, when the structure incorporating the buckling restraint brace 100 deforms during an earthquake and a compressive force N is generated as an axial force on the core material 10, for example, the narrow portion 11 of the core material 10 can undergo buckling deformation in a higher-order buckling mode in its strong axis direction.

[0056] At this time, by interposing the friction reduction means 18 between the end face 11b of the narrow portion 11 and the first end face 15a of the spacer 15, a large local frictional force is generated locally between the first end face 15a of the spacer 15 and the end face 11b of the narrow portion 11. Due to this local frictional force, local buckling in the strong axis direction occurs in the narrow portion 11, and damage to the side plate 40 due to this local buckling in the strong axis direction is suppressed. That is, instead of local buckling in the strong axis direction, in the entire area of the narrow portion 11, a higher-order buckling in the strong axis direction with a small deformation amount of the peak 11' of the buckling deformation occurs, and seismic energy can be effectively absorbed without damaging the side plate 40.

[0057] [Application Example of Buckling Restraint Brace to Structure] Next, with reference to FIGS. 7 to 9, an application example of the buckling restraint brace to a structure will be described. Here, FIG. 7 is a diagram showing a state in which the buckling restraint brace according to the embodiment is incorporated into a structure such as a wooden building. FIG. 8 is a diagram for explaining the deformation mode of the structure during a major earthquake and the additional bending moment at the buckling restraint brace joint caused by the deformation of the structure. Here, the "additional bending moment (or simply, additional bending)" means, for example, when the structure and the buckling restraint brace are greatly deformed during a major earthquake, a pressing force (supplementary stiffness force) acts on the wooden restraint member from the core material due to this deformation, and the bending moment that can be caused by this supplementary stiffness force. Note that the buckling restraint brace in the illustrated example may be incorporated into the structures of S-structured (S: Steel) buildings, RC-structured buildings, and SRC-structured (SRC: Steel Reinforced Concrete) buildings in addition to the structure of a wooden building.

[0058] The frame S shown in FIG. 7 is formed by wooden columns C and beams B that make up a wooden building or the like. Gusset plates GP formed of flat steel are attached to two corner portions at diagonal positions. Finned stiffeners FS are joined to the surface of the gusset plate GP by welding so as to be orthogonal to the surface. The finned stiffeners FS are joined to the gusset plate GP such that the core L3 of the finned stiffeners FS intersects the intersection O of the column core L1 of the column C and the beam core L2 of the beam B. And the buckling restraint brace 100 is also linearly arranged passing through both intersections O at diagonal positions.

[0059] The gusset plate GP and the wide-width portion 12 of the core material 10 are joined by high-tension bolts via a splice plate SP, and the finned stiffener FS and the reinforcing rib 13 are joined by high-tension bolts via a splice plate SP.

[0060] As shown in FIG. 8, when the structure deforms during a major earthquake, the following additional bending moment shown in formula (1) can act at the buckling restraint brace joint when the joint is regarded as rigid.

[0061]

Equation

[0062] According to the buckling restraint brace 100, the overall buckling of the buckling restraint brace 100 can be suppressed by restraining the core material 10 with a wooden restraint body 20 including a pair of wooden restraint members 30. Therefore, the buckling restraint brace 100 has strength against both overall buckling and higher-order buckling of the core material 10. Therefore, it becomes possible to form a frame S with excellent seismic resistance.

[0063] [Examination of overall buckling] Next, a design method for preventing the overall buckling of the buckling restraint brace will be described.

[0064] In the design of the buckling restraint brace, it is designed so as not to cause overall buckling of the buckling restraint brace by satisfying the following formula (2).

[0065]

Number

[0066] Here, the bending moment acting on the center of the restraint material can be expressed by the following formula (3).

[0067]

Number

[0068] The condition for preventing the overall buckling of the wooden restraint is to satisfy the following formula (4).

[0069]

Number

[0070] Formula (4) is shown in FIG. 9 as the overall buckling line of the buckling restraint brace. In FIG. 9, the upper side of the overall buckling line is the safe region, and the lower side is the dangerous region. The design axial force, Euler load, length of the general part of the core material, and yield bending resistance of the wooden restraint are set so as to enter the safe region. Note that the overall buckling line of the buckling restraint brace shown in FIG. 9 is valid for both the overall buckling in the weak axis direction and the overall buckling in the strong axis direction of the core material.

[0071] In addition to examining the relationship between the yield bending resistance of the wooden restraint described above and the acting bending moment, it is also advisable to examine that the allowable bending resistance of the short-term wooden restraint is greater than the bending moment acting at the time of core material yield (mathematical formulas are omitted).

[0072] [Examination of the embedment failure of the wooden restraint] Next, with reference to FIG. 10, a method for examining the embedment failure of the wooden restraint will be described. In the buckling restraint brace 100, in order to prevent the wooden restraint from being destroyed by the core material embedding into the wooden restraint, it is verified that the following formula (5) is satisfied.

[0073]

Number

[0074] Here, in addition to examining the relationship between the embedment strength of the above-described restraint material and the supplementary stiffness acting thereon, it is also advisable to examine that the allowable embedment strength of the short-term restraint material is greater than the supplementary stiffness acting at the time of core material yielding (mathematical expressions are omitted).

[0075] In addition, other embodiments in which other components are combined with the configurations and the like described in the above embodiments may be possible, and the present invention is not limited to the configurations shown here. In this regard, it can be changed without departing from the gist of the present invention and can be appropriately determined according to the application form.

Explanation of Signs

[0076] 10: Core material 11: Narrow width part 11a: Wide width surface 11b: End face 12: Wide width part 12': Width increasing part 12a: Wide width surface 12b: End face 12c: Bolt hole 13: Reinforcing rib 13a: Bolt hole 15: Spacer 15a: First end face 15b: Second end face 15c: Tapered surface 18: Friction reduction means (axial steel material, round steel) 18A: Friction reduction means (axial steel material) 18B: Friction reduction means (curved surface) 20: Wooden restraint body 30: Restraint material 35: Slit 40: Side plate 100: Buckling restraint brace G1: First gap G2: Second gap G3: The 3rd gap S: Structure (plane) C: Column B: Beam GP: Gusset plate FS: Fin stiffener SP: Splice plate

Claims

1. a steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members disposed so as to face two wide surfaces of the core material and a pair of side plates connecting the pair of restraint members, the core material includes a narrow-width portion where the width of the wide surface is relatively narrow on the central side in the longitudinal direction thereof, and a wide-width portion where the width of the wide surface is relatively wide on the end side in the longitudinal direction thereof, a first gap is provided between the end face of the narrow-width portion of the core material and the side plate, and a steel spacer is interposed in the first gap, a buckling restraint brace, characterized in that friction reducing means for reducing the frictional force between the two is provided between the spacer and the narrow-width portion.

2. a steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members having a U-shaped or L-shaped cross section disposed so as to face two wide surfaces of the core material, the core material includes a narrow-width portion where the width of the wide surface is relatively narrow on the central side in the longitudinal direction thereof, and a wide-width portion where the width of the wide surface is relatively wide on the end side in the longitudinal direction thereof, a first gap is provided between the end face of the narrow-width portion of the core material and the restraint member, and a steel spacer is interposed in the first gap, a buckling restraint brace, characterized in that friction reducing means for reducing the frictional force between the two is provided between the spacer and the narrow-width portion.

3. The buckling restraint brace according to claim 1 or 2, characterized in that the friction reducing means is a curved or tapered end face convex toward the other side on at least one of the spacer or the narrow-width portion.

4. The buckling restraint brace according to claim 1 or 2, characterized in that the friction reducing means is a shaft-shaped steel material having a curved surface or a tapered surface convex toward the other side from at least one of the spacer or the narrow-width portion and interposed between the spacer and the narrow-width portion.

5. The buckling restraint brace according to claim 1 or 2, characterized in that the friction reducing means is any one of round steel, wire mesh, wooden board, or butyl rubber interposed between the spacer and the narrow-width portion.

6. The buckling restraint brace according to claim 1 or 2, characterized in that a second gap is further provided between the end face of the wide-width portion and the side plate or the restraint member.

7. On the wide surface of the wide portion, a reinforcing rib orthogonal to the wide surface is joined to present a cross-sectional shape, Among the restraint members, a slit that does not interfere with the reinforcing rib is provided at a position corresponding to the reinforcing rib, The buckling restraint brace according to claim 1 or 2, wherein the reinforcing rib is accommodated in the slit with a third gap.

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