Buckling restraining brace

Abstract

To provide a buckling restraining brace capable of suppressing interference between a core material, and an outer spacer and a stiffener when relative displacement occurs between a core material, and an outer spacer and a stiffener during an earthquake.SOLUTION: A buckling restraining brace comprises: a core material 10 made of a steel plate material and having wide surfaces 11 with the same width throughout the entire longitudinal direction; a pair of steel restraining members 30 arranged opposite the two wide surfaces 11 of the core material 10; a pair of stiffeners 50 welded to both side surfaces 32 of the pair of restraining members 30 at sides of the core material 10 and extending in the longitudinal direction; and a pair of outer spacers 40 extending in the longitudinal direction and interposed between narrow surfaces 12 of the core material 10 facing the stiffeners 50 and the stiffeners 50. A longitudinal length of the outer spacers 40 is set shorter than a longitudinal length of the stiffeners 50. A first gap G1 is provided between an inner surface 51 of an end 53 of the stiffeners 50 and the narrow surface 12 of the core material 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a buckling-restrained brace. [Background technology]

[0002] Buckling-restrained braces, which have been designed to prevent buckling, have traditionally been used as braces to form building frames (column-beam frames, roof frames, etc.). Buckling-restrained braces come in a variety of stiffening configurations, including a steel core stiffened only with steel plates, a steel core stiffened with reinforced concrete (RC), and a steel core covered with steel and mortar.

[0003] The core material that constitutes a buckling-restrained brace has a constricted shape, with a narrow central section that serves as a plasticized section to absorb seismic energy and wide sections at both ends of the narrow section. The core material with the narrow and wide sections is manufactured by laser cutting or other processes on the left and right sides of the center of a steel plate of constant width in the longitudinal direction. Patent Document 1 proposes a buckling-restrained brace that includes this type of core material. The core material of the buckling-restrained brace described in Patent Document 1 further has an intermediate slit for adjusting strength, into which an internal deformation prevention member made of steel that serves as a spacer is inserted so as to be movable relative to the longitudinal direction. This spacer inserted into the slit inside the core material can be referred to as an internal spacer.

[0004] In the buckling restraint brace described in Patent Document 1, a pair of restraint members consisting of square steel pipes are arranged facing a pair of wide surfaces of a core member, and a pair of stiffeners are welded to both sides of the pair of restraint members on the sides of the core member.

[0005] In the core material of the above form, waste material is generated when a part of the steel plate is laser cut or the like, and the laser cutting or the like can reduce the production yield of the core material, so in order to prevent the generation of this waste material and the reduction in production yield, core materials with a constant width in the longitudinal direction are sometimes used. Furthermore, laser cutting is used to form slits in the core material into which inner spacers are inserted, but laser cutting makes the reduction in the production yield of the core material mentioned above even more pronounced.

[0006] For these reasons, Patent Document 2 proposes a buckling restrained brace in which so-called external spacers are arranged on the sides of the core material, instead of providing slits in the core material and inserting internal spacers, by making the width of the core material constant along its length to prevent the generation of waste material and a decrease in production yield. By installing external spacers, the gap (clearance) between the width of the core material in the strong axis direction and the width of the restraining material that restrains the core material can be controlled to a specified value.

[0007] The buckling-restrained brace (here, a buckling-restrained building material) described in Patent Document 2 is a buckling-restrained building material in which a core material is sandwiched between two buckling restraint members, and gap-retaining members for ensuring a predetermined amount of gap between the core material and the core-material-facing surfaces of the two buckling restraint members are interposed between the two buckling restraint members on either side of the core material in the longitudinal direction, and displacement-suppressing members for suppressing lateral displacement of the core material are arranged on either side of the core material in the longitudinal direction. The gap-retaining members are composed of a displacement-suppressing member and a gap-adjusting member interposed between the displacement-suppressing member and the gap-retaining-member-facing surface of at least one of the two buckling restraint members, and the gap-adjusting member is a low-strength member with lower strength than the core material. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6445862 [Patent Document 2] Patent No. 6644370 Summary of the Invention [Problem to be solved by the invention]

[0009] In the buckling restrained brace (buckling restrained building material) described in Patent Document 2, a gap retaining member equivalent to an outer spacer is disposed inside the buckling restrained member, and both are set to the same length in the longitudinal direction. Therefore, if the structural surface to which the buckling restrained brace is attached deforms during an earthquake and the core material that makes up the buckling restrained brace expands and contracts in the longitudinal direction, causing relative displacement between the buckling restrained member and the gap retaining member, there is a risk that they may interfere with each other.

[0010] The present invention was made in consideration of the above-mentioned problems, and relates to a buckling-restrained brace in which a pair of stiffeners are joined to a pair of restraint members facing the wide faces of a core member, and an outer spacer is provided between the core member and the stiffeners.The present invention aims to provide a buckling-restrained brace that can suppress interference between the core member and the outer spacers and stiffeners when relative displacement occurs between the core member and the outer spacers and stiffeners during an earthquake. [Means for solving the problem]

[0011] In order to achieve the above object, one aspect of the buckling restrained brace according to the present invention is as follows: A core material made of a steel plate material, the width of the wide surface being the same throughout the longitudinal direction; a pair of steel restraint members arranged to face the two wide surfaces of the core member; a pair of stiffeners welded to both side surfaces of the pair of restraint members on the sides of the core member and extending in the longitudinal direction; a pair of outer spacers extending in the longitudinal direction and interposed between the stiffener and the narrow surface of the core facing the stiffener, The length of the outer spacer in the longitudinal direction is set shorter than the length of the stiffener in the longitudinal direction, A first gap is provided between the inner surface of the end of the stiffener and the narrow surface of the core.

[0012] According to this aspect, in a buckling restraint brace in which a pair of stiffeners are joined to a pair of restraint members facing the wide surfaces of a core material and an outer spacer is provided between the core material and the stiffeners, the longitudinal length of the outer spacer is set shorter than the longitudinal length of the stiffeners, and a first gap is provided between the inner surface of the end of the stiffener and the narrow surface of the core material.Therefore, when relative displacement occurs between the core material and the outer spacers and stiffeners during an earthquake, interference between the core material and the stiffeners can be suppressed by the first gap, and since the outer spacers are shorter than the stiffeners, interference between the core material and the outer spacers can be suppressed.

[0013] Furthermore, because the width of the wide surface of the core material is the same throughout the entire longitudinal direction and because slits for arranging internal spacers inside the core material are not required, there is no need to process constrictions or slits in the core material using laser cutting or other processes, which significantly improves the production yield of the core material and improves the manufacturability of the buckling restraint brace.

[0014] Here, with regard to how much shorter the longitudinal length of the outer spacer should be relative to the longitudinal length of the stiffener, and how large the first gap should be set, the first gap and the distance between the end of the stiffener and the end of the outer spacer (relative distance between the end) will be set based on the amount of deformation (compression and expansion) of the core material when the frame is deformed by the set seismic force, and the amount of relative displacement between the end of the core material and the outer spacer and stiffener, respectively.For example, the first gap can be set by setting the relative distance between the end of the stiffener and the end of the outer spacer to about half the designed expansion of the core material.

[0015] Another aspect of the buckling restrained brace according to the present invention is: a second gap is defined between the restraint material and the wide surface of the core material; The outer spacer is attached to the stiffener, and a third gap is defined between the narrow surface of the core material and the outer spacer.

[0016] According to this aspect, a second gap is set between the restraining material and the wide surface of the core material, and an outer spacer is attached to the stiffening material to set a third gap between the narrow surface of the core material and the outer spacer.This allows the second gap to prevent buckling of the core material in the weak axis direction while preventing deformation of the core material in the weak axis direction from being suppressed, and the third gap to prevent buckling of the core material in the strong axis direction while preventing deformation of the core material in the strong axis direction from being suppressed.

[0017] Another aspect of the buckling restrained brace according to the present invention is: The core material is characterized in that reinforcing fins are welded to the two wide surfaces of the core material, extending from each end over a predetermined range in the longitudinal direction of the core material in a direction perpendicular to the wide surfaces.

[0018] According to this aspect, reinforcing fins are provided on the two wide surfaces of the core material, extending from each end over a predetermined range in the longitudinal direction of the core material, thereby effectively reinforcing the end of the core material that is joined to a bracket or the like of a structure. Here, end plates that extend in a direction perpendicular to the longitudinal direction are welded to the longitudinal ends of the core material, and the bracket and end plates of the structure can be joined to each other by bolts or the like.

[0019] Another aspect of the buckling restrained brace according to the present invention is: a first slit is provided in the stiffener at a position corresponding to the core material, the first slit extending from an end of the stiffener over a predetermined range in the longitudinal direction thereof, and a closing plate is attached to an outer surface of the stiffener to close the first slit; A fourth gap is provided between the narrow surface of the core material and the inner surface of the closure plate.

[0020] According to this aspect, a first slit is provided at a position corresponding to the core material of the stiffener, a blocking plate that blocks the first slit is attached to the outer surface of the stiffener, and a fourth gap larger than the above-mentioned first gap is provided between the narrow surface of the core material and the inner surface of the blocking plate, so that interference between the core material and the stiffener can be suppressed by the fourth gap.

[0021] Here, "a first slit is provided over a predetermined range from the end of the stiffener in its longitudinal direction" means, for example, that based on the deformation mode within the structural plane of the end of the core material during a major earthquake, the range within which the deformed core material can come into contact with the stiffener is set to a predetermined range, and the first slit is provided within this range.

[0022] Another aspect of the buckling restrained brace according to the present invention is: a protrusion extending outward from an end of the stiffener over a predetermined range in the longitudinal direction thereof is provided at a position of the stiffener corresponding to the core; A fourth gap is provided between the narrow surface of the core material and the inner surface of the convex portion.

[0023] According to this aspect, a convex portion that protrudes outward is provided at a position corresponding to the core material of the stiffener, and a fourth gap larger than the above-mentioned first gap is provided between the narrow surface of the core material and the inner surface of the convex portion, thereby making it possible to suppress interference between the core material and the stiffener by the fourth gap.

[0024] Another aspect of the buckling restrained brace according to the present invention is: The restraining material is characterized in that a second slit that prevents interference with the reinforcing fin is provided at a position corresponding to the reinforcing fin, with a fifth gap between the restraining material and the reinforcing fin.

[0025] According to this aspect, the second slits, which prevent interference with the reinforcing fins at positions corresponding to the reinforcing fins, are provided in the restraining material with a fifth gap between them, so that even when the reinforcing fins are long and interference between the reinforcing fins and the end regions of the restraining material is likely to occur, interference between the two is effectively prevented. Here, the fifth gap between the reinforcing fins and the end faces of the second slits is set to a width that prevents contact between the reinforcing fins and the second slits when the core material is deformed, for example, during a major earthquake. [Effects of the Invention]

[0026] As can be understood from the above explanation, the buckling restraint brace of the present invention has a pair of stiffeners joined to a pair of restraint members facing the wide faces of the core member, and is provided with an outer spacer between the core member and the stiffeners.When relative displacement occurs between the core member and the outer spacers and stiffeners during an earthquake, interference between the core member and the outer spacers and stiffeners can be suppressed. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is an exploded perspective view of an example buckling restrained brace according to embodiments. [Figure 2] FIG. 1 is a perspective view of an example of a buckling restrained brace according to embodiments. [Figure 3] FIG. 3 is a view taken along the line III-III in FIG. 2. [Figure 4] FIG. 4 is a view taken along the line IV-IV in FIG. 2. [Figure 5] FIG. 10 is a perspective view of another example of a buckling restrained brace according to embodiments. [Figure 6] FIG. 6 is a view taken along the line VI-VI in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a buckling restrained brace according to an embodiment will be described with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components will be designated by the same reference numerals, and redundant description may be omitted.

[0029] [Buckling restrained brace according to the embodiment] An example of a buckling-restrained brace according to an embodiment will be described with reference to Figures 1 to 6. Here, Figure 1 is an exploded perspective view of an example of a buckling-restrained brace according to an embodiment, and Figure 2 is a perspective view of an example of a buckling-restrained brace according to an embodiment. Also, Figures 3 and 4 are views taken along arrows III-III and IV-IV in Figure 2, respectively. Furthermore, Figure 5 is a perspective view of another example of a buckling-restrained brace according to an embodiment, and Figure 6 is a view taken along arrows VI-VI in Figure 5.

[0030] As shown in Figure 1, the buckling restraint brace 100 comprises a core material 10, a pair of steel restraint members 30 arranged opposite the two wide faces 11 of the core material 10, a pair of stiffeners 50 welded to the upper and lower side faces 32 of the pair of restraint members 30 on the sides of the core material 10 and extending in the longitudinal direction, and a pair of outer spacers 40 extending in the longitudinal direction and interposed between the narrow faces 12 of the core material 10 and the inner faces 51 of the stiffeners 50.

[0031] The core member 10 is formed of an elongated steel plate, and the width t0 of the wide surface 11 is constant over the entire area in the longitudinal direction.

[0032] It is preferable that the core material 10 be formed from steel with a low yield point, such as SN material (rolled steel for architectural structures) or LYP material (extremely low yield point steel), and by using core material 10 made from these materials, the yielding of the core material 10 will result in good earthquake energy absorption.

[0033] Because the core material 10 has a long, narrow rectangular shape in plan view, with the width t0 of its wide surface 11 being the same throughout the longitudinal direction, as shown in Patent Document 1, it has a narrow section in the center and wide sections at both ends, eliminating the need for processing work such as laser processing of the narrow transition section between them, improving the production yield of the core material 10 and improving the manufacturability of buckling restraint braces that use the core material 10 as a component.

[0034] At the widthwise center position of the two wide faces 11 of the core material 10, reinforcing fins 15 made of steel plates extending in a direction perpendicular to the wide faces 11 are welded from the longitudinal end portions 13 of each over a predetermined range t4 in the longitudinal direction of the core material 10. The reinforcing fins 15 in the illustrated example have a planar shape in which the width changes stepwise along the way, but they may also have a constant width or a shape in which the width changes in two or more steps.

[0035] By providing reinforcing fins 15 on the two wide faces 11 of the end 13 of the core material 10 and forming the end in a cross shape, the rigidity (particularly the rigidity in the weak axis direction) of the longitudinal end of the core material 10 is ensured. Therefore, the length of the reinforcing fins 15 (predetermined range t4) is set to a length that provides the required strength (bending rigidity and shear rigidity) to resist the cross-sectional force generated at the end of the core material 10 when the core material 10 is deformed during a major earthquake.

[0036] An end plate 17 is welded to an end 13 in the longitudinal direction of the core material 10 shown in Fig. 1. Here, "welding" in this specification refers to groove welding (full penetration welding, partial penetration welding), fillet welding, laser welding, or other welding that is appropriate for the strength and joining mode required for the joint.

[0037] A cylindrical steel protrusion 14 projects from the center of the wide surface 11 of the core material 10 in the longitudinal direction. The protrusion 14 is joined to the wide surface 11 by welding or the like.

[0038] When manufacturing the buckling restrained brace, a steel end plate 17 extending in a direction perpendicular to the longitudinal direction is welded to the longitudinal end 13 of the core material 10. The end plate 17 has multiple bolt holes 17a (two in the illustrated example) through which bolts are inserted when the buckling restrained brace is bolted to a bracket or the like (not shown) attached to the side of a column that forms the building frame when the buckling restrained brace is incorporated into the building frame (not shown).

[0039] The restraint member 30 is formed from a square steel pipe that is rectangular in cross section, and has a projection hole 31a on the opposing surface 31 that faces the wide surface 11 of the core material 10, into which the projection 14 of the core material 10 fits. Here, the restraint member may be formed from a channel steel or a shaped steel unit formed by assembling two angle irons into a rectangular frame shape, in addition to the square steel pipe.

[0040] At a position of the restraint material 30 corresponding to the reinforcing fin 15 attached to the core material 10, a second slit 33 is provided within a predetermined length t5 from the end 34 to prevent interference with the reinforcing fin 15 when assembling the restraint material 30.

[0041] Furthermore, a gap G0 of a predetermined width is provided between the second slit 33 and the end face of the reinforcing fin 15.

[0042] The width of this gap G0 is set to a width that prevents contact between the reinforcing fin 15 and the end face of the second slit 33 when the core material 10 is deformed in the strong axis direction during a major earthquake, for example. This prevents the reinforcing fin 15 from pressing against the end face of the second slit 33 during a major earthquake, thereby preventing damage to the end of the restraint material 30.

[0043] Furthermore, a fifth gap (not shown) is provided between the tip of the reinforcing fin 15 and the end of the second slit 33, and the length t5 of the second slit 33 is set to a length that prevents the tip of the reinforcing fin 15 from contacting the second slit 33 when the core material 10 is subjected to a compressive force and shrinks in the longitudinal direction during, for example, a major earthquake. This fifth gap also makes it possible to prevent the reinforcing fin 15 from pressing against the end face of the second slit 33 during a major earthquake, thereby preventing the end of the restraint material 30 from being damaged.

[0044] On each opposing surface 51 of the pair of stiffeners 50, at a position facing the narrow surface 12 of the core material 10, a steel outer spacer 40 having a length t2 shorter than the longitudinal length t1 of the stiffener 50 is fixed by spot welding or the like at multiple locations.

[0045] Here, the cross-sectional shape of the outer spacer 40 in the illustrated example, which is perpendicular to the longitudinal direction, is circular, but outer spacers whose cross-sectional shape is rectangular or other polygonal shapes may also be used.

[0046] Compared to a configuration in which a slit is provided in the core material and an inner spacer is inserted, the configuration in which the outer spacer 40 is disposed to the side of the narrow face 12 of the core material 10 as shown in the figure increases the cross-sectional rigidity of the core material 10 in the strong axis direction (the height of the core material in the strong axis direction is reduced by the width of the slit provided in the core material, thereby decreasing the cross-sectional rigidity), thereby making it possible to increase the buckling wavelength in the strong axis direction. This is preferable because it can suppress an increase in load on the compression side during deformation at the narrow face 12 of the core material 10.

[0047] In the illustrated example, the distance between the end 53 of the stiffener 50 and the end 42 of the outer spacer 40 is t3, which is half the difference between the longitudinal length t1 of the stiffener 50 and the length t2 of the outer spacer 40 attached to its center.

[0048] The cross-sectional view shown in Figure 3 shows a cross-section perpendicular to the longitudinal direction of the general part at the center of the buckling restraint brace 100, and a third gap G3 of width t8 is provided between the narrow surface 12 of the core material 10 and the outer spacer 40.

[0049] On the other hand, as shown in FIGS. 3 and 4, a second gap G2 having a width t7 is provided between the wide surface 11 of the core material 10 and the opposing surface 31 of the restraining material 30.

[0050] The width t7 of the second gap G2 provided between the opposing surface 31 of the restraint member 30 and the wide surface 11 of the core material 10 is set to a width that prevents buckling of the core material 10 in the weak axis direction during a major earthquake, while preventing suppression of deformation of the core material 10 in the weak axis direction during a major earthquake, and can effectively absorb earthquake energy.

[0051] On the other hand, the width t8 of the third gap G3 provided between the outer spacer 40 and the narrow surface 12 of the core material 10 is set to a width that prevents buckling of the core material 10 in the strong axis direction during a major earthquake, while preventing suppression of deformation of the core material 10 in the strong axis direction during a major earthquake, and can effectively absorb earthquake energy.

[0052] Furthermore, since the length t2 of the outer spacer 40 is set shorter than the longitudinal length t1 of the stiffener 50, as shown in Figure 4, the outer spacer 40 is not present at the end 53 of the stiffener 50, and a first gap G1 of width t6 is provided between the inner surface 51 of the stiffener 50 and the narrow surface 12 of the core material 10.

[0053] In this way, the longitudinal length t2 of the outer spacer 40 is set shorter than the longitudinal length t1 of the stiffener 50, and a first gap G1 of width t6 is provided between the inner surface 51 of the end 53 of the stiffener 50 and the narrow surface 12 of the core material 10. This makes it possible to suppress interference between the narrow surface 12 of the core material 10 and the inner surface 51 of the stiffener 50 when relative displacement occurs between the core material 10, the outer spacer 40, and the stiffener 50 during a major earthquake. Furthermore, because the outer spacer 40 is shorter than the stiffener 50, the outer spacer 40 is not present in the area of ​​the end 53 of the stiffener 50 as shown in FIG. 4 , and interference between the narrow surface 12 of the core material 10 and the outer spacer 40 can also be suppressed.

[0054] The buckling restraint brace 100A shown in Figures 5 and 6 differs from the buckling restraint brace 100 in that a first slit 55 is provided over a predetermined range in the longitudinal direction from the end of the stiffener 50A at a position corresponding to the narrow surface 12 of the core material 10 of the stiffener 50A, and a blocking plate 57 that blocks the first slit 55 is attached to the outer surface 52 of the stiffener 50A.

[0055] A fourth gap G4 with a width t7 is provided between the narrow surface 12 of the core material 10 and the inner surface 58 of the closure plate 57. As is clear from a comparison with the first gap G1 with a width t6 shown in FIG. 4, a larger gap can be provided between the narrow surface 12 of the core material 10 and the stiffener 50A (or the closure plate 57 joined thereto). Therefore, when relative displacement occurs between the core material 10 and the outer spacer 40 and the stiffener 50A during a major earthquake, the fourth gap G4 can prevent interference between the narrow surface 12 of the core material 10 and the closure plate 57 located outside the first slit 55b of the stiffener 50A. Furthermore, because the outer spacer 40 is shorter than the stiffener 50A, the outer spacer 40 is not present in the end area of ​​the stiffener 50A, as shown in FIG. 6, and interference between the narrow surface 12 of the core material 10 and the outer spacer 40 can also be prevented.

[0056] Although not shown here, in addition to a configuration in which a first slit is provided in the stiffener and a blocking plate that blocks the first slit is attached to the outside, a configuration in which a convex portion that protrudes outward from the end of the stiffener over a predetermined range in the longitudinal direction is provided at a position in the stiffener corresponding to the core material, and a fourth gap is provided between the narrow surface 12 of the core material 10 and the inner surface of the convex portion, may also be used.

[0057] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0058] 10: Core material 11: Wide surface 12: Narrow surface 13:End 14: Protrusion 15: Reinforcement fin 17: End plate 17a: Bolt hole 30: Restraint material (square steel pipe) 31: Opposite surface 32: Side 33: Second slit 34: Edge 40: Outer spacer 50, 50A: Stiffener 51: Inner surface (opposing surface) 52:Outer surface 55: First slit 57: Occlusion plate 58: Inner surface 100,100A: Buckling restrained brace G0: Gap G1: First gap G2: Second gap G3: Third gap G4: 4th gap

Claims

1. A core material made of a steel plate material, the width of the wide surface being the same throughout the longitudinal direction; a pair of steel restraint members arranged to face the two wide surfaces of the core member; a pair of stiffeners welded to both side surfaces of the pair of restraint members on the sides of the core member and extending in the longitudinal direction; a pair of outer spacers extending in the longitudinal direction and interposed between the stiffener and the narrow surface of the core facing the stiffener, The length of the outer spacer in the longitudinal direction is set shorter than the length of the stiffener in the longitudinal direction, A buckling restrained brace, characterized in that a first gap is provided between the inner surface of the end of the stiffener and the narrow surface of the core material.

2. a second gap is defined between the restraint member and the wide surface of the core member; 2. The buckling restraint brace of claim 1, wherein the outer spacer is attached to the stiffener, and a third gap is defined between the narrow surface of the core and the outer spacer.

3. 3. A buckling restraint brace as described in claim 1 or 2, characterized in that reinforcing fins are welded to the two wide faces of the core material, extending in a direction perpendicular to the wide faces from each end over a predetermined range in the longitudinal direction of the core material.

4. a first slit is provided in the stiffener at a position corresponding to the core material, the first slit extending from an end of the stiffener over a predetermined range in the longitudinal direction thereof, and a closing plate is attached to an outer surface of the stiffener to close the first slit; 3. The buckling restraint brace according to claim 1, wherein a fourth gap is provided between the narrow surface of the core material and the inner surface of the closure plate.

5. a protrusion extending outward from an end of the stiffener over a predetermined range in the longitudinal direction thereof is provided at a position of the stiffener corresponding to the core; 3. The buckling restraint brace according to claim 1, wherein a fourth gap is provided between the narrow surface of the core material and the inner surface of the convex portion.

6. 4. The buckling restraint brace according to claim 3, wherein a second slit is provided in the restraint material at a position corresponding to the reinforcing fin to prevent interference with the reinforcing fin, with a fifth gap between the restraint material and the reinforcing fin.

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