JP2014122462A - Buckling restrained brace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buckling restrained brace which achieves strength high enough to resist even repeated big earthquakes and in which the occurrence of a camber after being welded can be effectively suppressed.SOLUTION: A pair of buckling restraining members 3 and 4 arranged along both surfaces of a brace core material 2 are connected together by weld zones 18 in a plurality of locations while the brace core material 2 is held between the buckling restraining members. In this case, the plurality of weld zones 18 are arranged in such a manner that central areas of the buckling restraining members 3 and 4 are lower in arrangement density of the weld zones 18 than end areas at both ends adjacent to the central areas.

Description

  The present invention relates to a buckling restrained brace.

  Conventionally, what is shown in patent documents 1 is known as a buckling restraint brace. The buckling restraint brace shown in Patent Document 1 has a structure in which a brace core material having a long plate shape is sandwiched between a pair of buckling restraining members in the thickness direction, and the buckling restraining members are joined together by welding in this state.

JP 2008-75280 A

  In the conventional buckling restrained brace described above, warping occurs due to shrinkage of the welded portion after welding. For this, a countermeasure is taken in which a buckling restraining member is given a reverse warp in advance.

  However, when the warpage generated after welding is large, it is necessary to manufacture a buckling restraining member to which a large amount of reverse warpage is applied, which is problematic in terms of productivity and strength.

  On the other hand, it is also possible to suppress the occurrence of warping by reducing the number of welding locations. However, simply reducing the number of welds makes it difficult to secure a strength that can withstand repeated large earthquakes.

  The present invention has been invented in view of the above problems, and is capable of realizing a strength sufficient to withstand repeated large earthquakes and effectively suppressing the occurrence of warpage after welding. It is an object to provide a restrained brace.

  In order to solve the above problems, the present invention is a buckling restrained brace having the following configuration.

  The present invention comprises a brace core material that is in the form of a long plate, and a pair of buckling restraining members disposed along both surfaces in the thickness direction of the brace core material, This is a buckling restrained brace that is joined by a plurality of welds in a state where the brace core material is sandwiched in the thickness direction. The welded portions are arranged at a plurality of positions spaced in the longitudinal direction of the buckling restraining member, and the end portion is formed by a central region of the buckling restraining member and end regions at both ends adjacent thereto. The density of the welded portion over the entire length is set so that the density of the welded portion is sparser in the central region than in the region.

  In the present invention, the pair of buckling restraining members includes a grooved metal material having flange portions projecting from both end edges in the width direction of the web having a long plate shape, and between the flange portions at both ends of the grooved metal material. It is preferable that the flange part which the said groove type metal material has at both ends is respectively couple | bonded with the said metal material by the said some welding part.

  Furthermore, in the present invention, the metal material is a square metal tube having four corners, and one surface of the square metal tube on the outer periphery presses against one side of the brace core material and buckles. A first buckling restraining surface that restrains buckling, and the inner surface of the web of the grooved metal material is pressed against the other one surface of the brace core material to become a second buckling restraining surface that restrains buckling, The first buckling of the flange portions at both ends and the four corner portions of the square metal tube in a state where the square metal tubes are fitted between the flange portions at both ends of the grooved metal material. It is preferable that two said corner | angular parts located in the side away from the constraining surface, or these vicinity parts are couple | bonded by the said some welding part.

  Furthermore, in the present invention, the tip of the flange portion of the grooved metal material protrudes to the side away from the first buckling restraint surface than the rectangular metal tube, and more than the plurality of welded portions. It is preferable to provide it so as to protrude to the side away from the first buckling restraint surface.

  Furthermore, in the present invention, both end portions in the longitudinal direction of the brace core material have a reinforcing material protruding from the center portion in the width direction of the one side surface, and both end portions in the longitudinal direction of the square metal tube are The first buckling constraining surface has slit portions that are notched at both ends, a portion of the reinforcing material in the longitudinal direction is disposed in the slit portion, and the remaining portion of the reinforcing material in the longitudinal direction is the square metal tube. It is preferable to be provided so as to protrude from the center.

  The present invention achieves the strength that can withstand repeated large earthquakes and can effectively suppress the occurrence of warpage after welding.

It is the perspective view which fractured | ruptured partially the buckling restraint brace of one Embodiment of this invention. It is the XX sectional view taken on the line of FIG. It is the YY sectional view taken on the line of FIG. It is a disassembled perspective view of a buckling restraint brace same as the above. It is explanatory drawing at the time of a deformation | transformation force acting on the brace core material with which a buckling restraint brace same as the above is equipped, (a) is the case where the deformation force of the out-of-plane direction of a brace core material acts, (b) is a brace core material. This is a case where a deforming force in the in-plane direction is applied. The example which fixed the connection member to the connection part of the edge part of a buckling restraint brace same as the above is shown, (a) is a front view, (b) is a bottom view, (c) is an expanded sectional view. It is a front view of the load-bearing frame comprised using the buckling restraint brace same as the above. The connection member used for the same strength frame is shown, (a) is a plan view, (b) is a bottom view, and (c) is a side view. The arrangement | positioning of the junction part in a buckling restraint brace same as the above is shown, (a) is a front view, (b) is a bottom view.

  The present invention will be described based on embodiments shown in the accompanying drawings.

  1 to 9 show a buckling restrained brace 1 according to an embodiment of the present invention. In the following, first, the overall configuration of the buckling restrained brace 1 of the present embodiment and the load-bearing frame 24 using the same will be described.

  As shown in FIGS. 1 and 4, the buckling restrained brace 1 includes a brace core material 2 that is a long plate, a first buckling restraining member 3 that is a long metal member, and a long metal that is also long. The main body is configured using the second buckling restraining member 4 which is a member.

  The long plate-like brace core material 2 is made of steel such as carbon steel, stainless steel, alloy steel, but is not limited to this material, and may be made of other materials such as aluminum. . Both ends of the brace core material 2 in the longitudinal direction serve as connection portions 13 for connection to building structural materials (columns, beams, etc.).

  On one side of the brace core material 2, the reinforcing material 11 is fixed to both ends in the longitudinal direction. The reinforcing material 11 is fixed to the intermediate portion in the width direction of the brace core material 2 along the longitudinal direction.

  The first buckling restraining member 3 is formed of a square metal cylinder 5 made of a material such as carbon steel, stainless steel, alloy steel, or aluminum. The rectangular metal cylinder 5 is a rectangular cylindrical metal material having four corners.

  The square metal cylinder 5 is disposed over substantially the entire length of one side of the brace core material 2 (upper surface in FIGS. 2 and 3) in the longitudinal direction. One surface (the lower surface in FIGS. 2 and 3) of the square metal tube 5 is a first buckling restraint surface 6 that is located opposite to the one surface of the brace core material 2. The first buckling restraint surface 6 is a surface that restrains the buckling of the brace core material 2. Furthermore, the slit part 10 which notches the both ends of the 1st buckling restraining surface 6 in a longitudinal direction and an inner-outer direction is formed in the both ends of the longitudinal direction of the square metal cylinder 5. FIG.

  The second buckling restraining member 4 is formed of a groove-type metal material 7 made of a material such as carbon steel, stainless steel, alloy steel, or aluminum.

  The grooved metal material 7 is arranged over substantially the entire length in the longitudinal direction of the other one surface (the lower surface in FIGS. 2 and 3) of the brace core material 2. The groove-shaped metal material 7 is a member having a U-shaped cross section in which flange portions 9 are projected from both end edges in the width direction of the web 12 having a long plate shape. The inner surface (the upper surface in FIGS. 2 and 3) of the web 12 serves as a second buckling restraint surface 8 that faces the other one surface of the brace core material 2. The second buckling restraint surface 8 is a surface that restrains the buckling of the brace core 2 together with the first buckling restraint surface 6.

  The projecting lengths of both flange portions 9 of the groove-shaped metal material 7 project so as to exceed one surface (side surface in FIGS. 2 and 3) orthogonal to the first buckling restraint surface 6 of the square metal tube 5. , Each set. The protruding lengths of both flange portions 9 are the same.

  The dimensions in the longitudinal direction of the square metal cylinder 5 and the grooved metal material 7 are the same or substantially the same, and are set slightly shorter than the dimensions in the longitudinal direction of the brace core material 2.

  In the buckling restrained brace 1 of the present embodiment, the brace core material 2, the square metal tube 5, and the groove metal material 7 are assembled as follows.

  That is, as indicated by a hollow arrow in FIG. 4, the brace core material 2 is fitted into the groove space 23 between both flange portions 9 from the opening between the two flange portions 9 of the groove-shaped metal material 7, and then the corner The mold metal cylinder 5 is fitted. By fitting in this order, one side of the brace core material 2 comes into contact with the second buckling restraint surface 8 and the other side of the brace core material 2 comes into contact with the first buckling restraint surface 6.

  Here, the two corners located on the side away from the first buckling restraint surface 6 among the four corners of the square metal cylinder 5 are the portions located on the tip side of both flange portions 9. In FIG. Note that both flange portions 9 may be fixed to the square metal tube 5 in the vicinity of the two corner portions located on the side away from the first buckling restraint surface 6.

  The fixing here is performed by providing the welded portion 18. As shown in FIG. 1, the welds 18 are arranged at a plurality of locations spaced in the longitudinal direction. The arrangement pattern of the welds 18 will be described later with reference to FIG.

  The brace core material 2 is fixed to the square metal tube 5 or the grooved metal material 7 at an arbitrary position in the longitudinal direction. For example, the brace core material 2 is fixed to the square metal tube 5 and the groove metal material 7 by welding at one end in the longitudinal direction. As a result, the brace core material 2, the square metal tube 5, and the groove metal material 7 can be relatively moved except for one fixed portion.

  In the buckling-restrained brace 1 formed as described above, as shown in FIG. 1 and the like, the connecting portions 13 at both ends in the longitudinal direction of the brace core material 2 are connected to the square metal tube 5 and the grooved metal material 7. It protrudes from both ends in the longitudinal direction.

  In addition, among the reinforcing members 11 provided on both ends of one side of the brace core material 2, a part in the longitudinal direction is disposed in the slit part 10, and the remaining part in the longitudinal direction is the square metal cylinder 5. Projecting from both ends in the longitudinal direction of the groove-shaped metal material 7.

  The reinforcing material 11 effectively reinforces the portion near the connecting portion 13 where the buckling deformation is most concentrated in the brace core material 2. That is, the reinforcing material 11 extends from the connection portion 13 that is the end portion in the longitudinal direction of the brace core material 2 to the portion of the brace core material 2 that faces the end portion in the longitudinal direction of the square metal tube 5. Effectively reinforce the area.

  Moreover, in this buckling restraint brace 1, with respect to the full length and full width of the part except the connection part 13 among both surfaces of the brace core material 2, the 1st buckling restraint surface 6 which the square metal cylinder 5 has, respectively The second buckling restraining surface 8 of the groove-type metal material 7 comes into contact, and restrains the buckling of the brace core material 2.

  Further, in this buckling restraint brace 1, the protruding length of both flange portions 9 of the grooved metal material 7 is set to the side surface of the square metal tube 5 (that is, one surface orthogonal to the first buckling restraint surface 6), The size is set to be larger than the welded portion 18. Therefore, the cross-sectional secondary moment with respect to the out-of-plane of the grooved metal material 7 is set large, and the structure is more difficult to deform.

  As a result, even if a compressive force acts on the brace core material 2 and a force that moves so as to wave in the out-of-plane direction (see the arrow in FIG. 5A) is applied, the groove-shaped metal material 7 is not welded. Therefore, the groove-type metal material 7 can be made thinner.

  In addition, the two flange portions 9 of the groove-shaped metal material 7 are welded at two corner portions located on the side away from the first buckling restraining surface 6 of the square metal tube 5 or in the vicinity of the corner portions, respectively. Since it is fixed to the square metal cylinder 5, even if a compressive force acts on the brace core 2 and a force that moves in the in-plane direction as shown by the arrow in FIG. The deformation of the material 7 can be reduced, and the buckling restraint performance in the in-plane direction is improved.

  The buckling restrained brace 1 having the above-described configuration is connected to a building structural material (column, beam, etc.) using a connecting portion 13.

  In connection, for example, as shown in FIGS. 6 and 7, the connection members 15 and 16 are used for connection.

  FIG. 6 shows an example in which the connection member 15 is fixed to one end of the buckling restrained brace 1 in advance. In the case of this example, as shown in FIG. 7, two buckling-restraining braces 1 each having a connecting member 15 fixed to one end are used, and these buckling-restraining braces 1 are welded to the upper and lower portions of the side surface of the support column 17 respectively. Stick. Then, the other end portions of the two buckling restrained braces 1 are fixed to the common connecting member 16 by welding, thereby forming the load-bearing frame 24.

  The connection member 15 has a pair of fixing pieces 19 arranged in parallel. The connection member 15 is fixed to the buckling restraint brace 1 by welding the connection portion 13 at one end of the buckling restraint brace 1 between the pair of fixed pieces 19.

  As shown in FIG. 8, the connecting member 16 is formed by connecting and fixing the upper ends and the lower ends of a pair of fixed pieces 20 arranged in parallel via connecting pieces 22. The upper and lower connecting pieces 22 each have a bolt hole 21.

  The connecting member 16 has the lower end of the buckling restraint brace 1 located on the upper side disposed between the upper parts of the pair of fixed pieces 20 and fixed by welding, and the upper end of the buckling restraint brace 1 located on the lower side. A part is arrange | positioned between the lower parts of a pair of fixed piece 20, and it adheres by welding.

  In the load-bearing frame 24 formed in this way, for example, a support column 17 is erected between a building base and a beam, and the support column 17 is connected to the base or beam with a bolt or the like. Are connected to another adjacent column. Further, a support column 17 may be provided between the upper and lower beams, and the support column 17 may be connected to the upper and lower beams with a bolt or the like.

  By the way, when welding the connection part 13 of the one end side which the buckling restraint brace 1 has to the connection member 15, as shown in FIG. Both ends in the width direction of one side are fixed to the pair of fixed pieces 19 by welding. Similarly, when welding the connecting portion 13 on the other end side of the buckling restrained brace 1 to the connecting member 16, both widthwise end portions on one side of the connecting portion 13 on which the reinforcing material 11 is not projected are provided. The two fixed pieces 20 are fixed by welding. According to this, welding can be performed without being disturbed by the reinforcing material 11.

  In the above, based on FIGS. 1-8, the whole structure of the buckling restraint brace 1 of this embodiment and the strength frame 24 formed using this was demonstrated.

  Next, the arrangement pattern of the welds 18 formed by flare welding will be described with reference to FIG.

  As described above, the welded portion 18 joins the square metal tube 5 and the grooved metal material 7 with the long plate-like brace core material 2 sandwiched therebetween. The welds 18 are arranged in a line along the longitudinal direction of the buckling restraint brace 1.

  That is, one of the pair of corners located on the side away from the first buckling restraint surface 6 of the square metal cylinder 5 and the flange 9 on the side located adjacent to the corner are It is fixed by seven convenient welds 18 located at the boundary between the corner and the flange 9. Similarly, the other of the pair of corners located on the side away from the first buckling restraint surface 6 of the square metal tube 5 and the flange 9 on the side located adjacent to the corner are: It is fixed by seven convenient welds 18 located at the boundary between the corner and the flange 9. In the present text, a group of seven welds 18 arranged in a line along the longitudinal direction is referred to as a series of weld groups.

  In a series of weld groups, the longitudinal dimensions of the seven welds 18 are the same or substantially the same, specifically, 15 mm. Moreover, the dimension of the mutual width direction of these welding parts 18 is also provided in the same or substantially the same.

  On the other hand, the arrangement density in the longitudinal direction of the welded portion 18 is set so as to be sparse in the central region A1 in the longitudinal direction and dense in the end region A2 on both sides adjacent to the central region A1 in the longitudinal direction. Yes.

  Specifically, the welds 18 are arranged at a pitch of P1 = 280 mm in the central region A1. On the other hand, in the end region A2, the welded portions 18 are arranged at a pitch of P2 = 140 mm. The center area A1 is an area of about ½ of the entire length, and the end areas A2 on both sides are areas of about ¼ of the entire length. That is, the density of the weld groups on both sides in the width direction is set so that the welded portion 18 is arranged at a density twice as high in the end region A2 than in the central region A1 that occupies about half of the total length. .

  In the buckling restraint brace 1, it is particularly effective that the welds 18 are densely arranged on the end side in the longitudinal direction in order to maintain a strength sufficient to withstand repeated large earthquakes. On the other hand, in order to suppress the overall warp generated in the buckling restrained brace 1 after welding, it is particularly effective that the welded portion 18 is sparsely arranged at the central portion in the longitudinal direction. The density of the welded portion 18 set in the present embodiment is a comprehensive consideration of these problems and effects.

  In other words, by setting the above-described density in the weld groups on both sides in the width direction, warping occurring in the buckling-restrained brace 1 after welding is suppressed as much as possible while maintaining a strength sufficient to withstand repeated large earthquakes. Is possible.

  To confirm this, seven welds 18 each having a length of 15 mm are arranged on both sides in the sparse and dense arrangement shown in FIG. 9 and five welds 40 mm long on both sides, not shown, at a pitch of 280 mm. The force test was repeatedly performed with and evenly arranged. In this test, repeated pressurization of ± 1/50 rad was performed on the buckling restrained brace 1 fixed in an inclined posture.

  According to the repeated pressurization test, the weld length meter is 15 × 7 × 2 = 210 mm in the sparse / dense arrangement of FIG. 9, although it is about half of the weld length meter 40 × 5 × 2 = 400 mm in the uniform arrangement. The number of times until breakage was 56 to 71 in the case of the dense arrangement, and 29 to 44 in the case of the uniform arrangement.

  Furthermore, in order to confirm the effect of suppressing warpage, FEM model analysis was performed on the buckling restrained brace 1 having the same sparse arrangement and equal arrangement as in the repeated pressurization test under the condition that the weld 18 contracts by 3.6%. went.

  According to the FEM model analysis described above, the total warpage amount is 1.04 mm in the sparse / dense arrangement of FIG. 9, and the total warpage amount is 2.64 mm in the uniform arrangement. The result was obtained that the amount was suppressed to about 0.4 times.

  For further comparison, the same FEM analysis was performed for the case where the square metal tube 5 and the grooved metal material 7 were welded over the entire length on both sides in the width direction. A result of 0.03 mm was obtained.

  As described above, also from the results of the repeated pressurization test and the FEM model analysis, in the buckling restrained brace 1 of the present embodiment, the welded portion 18 is provided at a plurality of locations spaced in the longitudinal direction of the buckling restrained brace 1. In the central region A1 of the buckling restrained brace 1 and the end regions A2 at both ends adjacent to the central region A1, the central region A1 has a lower arrangement density of the welds 18 than the end region A2. As described above, since the arrangement density of the welded portions 18 over the entire length is set to be sparse and dense, it is possible to maintain a strength sufficient to withstand repeated large earthquakes and to suppress warping generated in the buckling restrained brace 1 after welding. It can be seen that both are achieved at a high level.

  In addition, in the buckling restrained brace 1 of the present embodiment, the pair of buckling restraining members 3 and 4 are grooved metal materials in which the flange portions 9 are projected from both end edges in the width direction of the web 12 which is a long plate shape. 7 and a metal material (square metal cylinder 5) fitted between the flange portions 9 at both ends of the grooved metal material 7. The flange portions 9 which the groove-type metal material 7 has at both ends are respectively coupled to the metal material by the plurality of welded portions 18 which are densely and dispersedly arranged as described above.

  Thereby, a functional buckling restrained brace 1 in which the brace core material 2 is sandwiched with a lightweight and high-strength structure in which the metal material is fitted into the groove-type metal material 7 can be obtained. Moreover, since the welds 18 are arranged densely as described above, they can withstand repeated large earthquakes, and warpage after welding is also suppressed.

  In addition, the metal material here may be other than the square metal cylinder 5 shown in the embodiment. For example, the first buckling restraint surface 6 among the four plate portions constituting the square metal cylinder 5 of the embodiment is provided. The plate part to be formed may be a metal material formed by being separated at the center part in the width direction, or the plate located on the opposite side to the plate part constituting the first buckling restraint surface 6 It may be a metal material formed by separating the portions at the center in the width direction. It is also possible to use a T-shaped metal material having the first buckling restraint surface 6. Regardless of the shape, the first buckling restraint surface 6 is fitted between the flange portions 9 at both ends of the grooved metal material 7 and sandwiches the brace core material 2 between the grooved metal material 7. If it is a metal material, there exists the same effect.

  Furthermore, in the present embodiment, the metal material is a square metal tube 5 having four corners, and one surface of the square metal tube 5 on the outer periphery presses against one side of the brace core material 2. The first buckling restraint surface 6 restrains buckling. The inner surface of the web 12 included in the grooved metal material 7 becomes the second buckling restraining surface 8 that presses against the other surface of the brace core material 2 and restrains buckling. Then, in a state where the square metal tube 5 is fitted between the flange portions 9 at both ends of the groove-shaped metal material 7, the first seat among the flange portions 9 at both ends and the four corner portions of the square metal tube 5. The two corners located on the side away from the bending restraint surface 6 or the vicinity thereof are joined by the plurality of welds 18 arranged in a dense and distributed manner as described above.

  Thereby, even when a compressive force acts on the brace core material 2 and a force that moves in the in-plane direction or a force that moves so as to wave in the out-of-plane direction, the groove-type metal material 7 The deformation can be reduced, and as a result, the grooved metal material 7 can be made thinner.

  Furthermore, in the present embodiment, the tip of the flange portion 9 of the grooved metal material 7 protrudes to the side away from the first buckling restraint surface 6 rather than the square metal tube 5, and the above-mentioned density It is provided so as to protrude to the side away from the first buckling constraining surface 6 rather than the plurality of welded portions 18 dispersedly arranged.

  Thereby, the cross-sectional secondary moment with respect to the out-of-plane of the groove-type metal material 7 is set to be larger, and the structure is more difficult to deform.

  Furthermore, in this embodiment, the both ends of the longitudinal direction of the brace core material 2 have the reinforcing material 11 which protrudes from the width direction center part of one single side | surface. Both ends of the rectangular metal tube 5 in the longitudinal direction have slit portions 10 that cut out both ends of the first buckling restraint surface 6. A part of the reinforcing material 11 in the longitudinal direction is disposed in the slit portion 10, and the remaining part of the reinforcing material 11 in the longitudinal direction is provided so as to protrude from the rectangular metal tube 5.

  Thereby, in the brace core material 2, it is possible to reinforce the vicinity of the connection portion 13 where buckling deformation is most likely to concentrate, and the strength of the entire buckling restraint brace 1 is further improved.

  Although the present invention has been described based on the embodiments shown in the accompanying drawings, the present invention is not limited to the above-described embodiments, and appropriate design changes are made within the intended scope of the present invention. It is possible.

DESCRIPTION OF SYMBOLS 1 Buckling restraint brace 2 Brace core material 3 1st buckling restraint member 4 2nd buckling restraint member 5 Square metal cylinder 6 1st buckling restraint surface 7 Groove type metal material 8 2nd buckling restraint surface 9 Flange part 10 Slit part 11 Reinforcement material 12 Web 13 Connection part 18 Welding part A1 Central area A2 End area

Claims (5)

A brace core material having a long plate shape and a pair of buckling restraining members disposed along both sides of the brace core material in the thickness direction, the pair of buckling restraining members being attached to the brace core material; A buckling restrained brace that is joined by a plurality of welds in a state of being sandwiched in the thickness direction,
The welded portions are arranged at a plurality of positions spaced in the longitudinal direction of the buckling restraining member, and the end portion is formed by a central region of the buckling restraining member and end regions at both ends adjacent thereto. A buckling restrained brace characterized in that the arrangement density of the welds over the entire length is set so that the arrangement density of the welds is sparser in the central area than in the area. The pair of buckling restraining members includes a grooved metal material having flange portions projecting from both end edges in the width direction of the long web, and a metal fitted between the flange portions at both ends of the grooved metal material. Consisting of materials,
2. The buckling restrained brace according to claim 1, wherein each of the flange portions of the groove metal material at both ends is coupled to the metal material by a plurality of the weld portions. The metal material is a square metal tube having four corners,
One surface of the square metal cylinder on the outer periphery is a first buckling restraining surface that restrains buckling by pressing against one side of the brace core,
The inner surface of the web of the groove-type metal material is a second buckling restraining surface that restrains buckling by pressing against the other side of the brace core material,
The first seat among the flange portions at both ends and the four corner portions of the square metal tube in a state where the square metal tubes are fitted between the flange portions at both ends of the grooved metal material. The buckling constraining brace according to claim 2, wherein the two corners located on the side away from the bending constraining surface or the vicinity thereof are joined by a plurality of the welds. The tip of the flange portion of the groove metal material is
Protruding to the side away from the first buckling constraining surface from the square metal tube, and projecting to the side away from the first buckling constraining surface from the plurality of welds. The buckling restrained brace according to claim 3. Both end portions in the longitudinal direction of the brace core material have a reinforcing material protruding from the center portion in the width direction of the one side surface,
Both ends in the longitudinal direction of the rectangular metal cylinder have slit portions that cut out both ends of the first buckling restraint surface,
4. A portion of the reinforcing material in the longitudinal direction is disposed in the slit portion, and the remaining portion of the reinforcing material in the longitudinal direction is provided so as to protrude from the rectangular metal tube. Or the buckling restraint brace of 4.

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