Buckling Restrained Brace

Abstract

To provide a buckling restraint brace capable of preventing the occurrence of a drop-off of a member or a non-reinforcable area when a core material deforms while achieving the same effects of adjusting the axial force of the core material and suppressing the decrease in strength in the strong axis direction by a conventional structure in which a spacer is inserted into a slit in a core material.SOLUTION: A buckling restraint brace 100 includes: a steel plate core material 10; and a pair of restraining materials 30 composed of a square steel pipe arranged facing two wide surfaces 10a of the core material 10. A first unit 15A and a second unit 15B are provided to form the axial force adjustment means of the core material 10. The first unit 15A has one through hole 16 A and two notches 17 that communicate one through hole 16A and extending in one side. The second unit 15B has one through hole 16B and two notches 17 which communicate with the one through hole 16B and extending on both left and right sides thereof.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] Patent Document 1 proposes a buckling-restrained brace in which a core member is restrained by restraining members formed of a pair of square steel pipes, and which prevents localized failure of the restraining members when subjected to compressive force from the core member. Specifically, the buckling-restrained brace includes a core member with joints at both ends of the plate-like portion for joining to other members, and restraining members arranged opposite each face of the plate-like portion perpendicular to the weak axis direction.

[0004] In this buckling-restrained brace, slits are provided on the wide faces of the core material to adjust the axial force (or strength) acting on the core material. When the core material is subjected to axial force (compression), these slits effectively induce higher-order mode buckling in the weak axis direction of the core material. However, there is a trade-off between the slits on the wide faces, which reduces the strength of the core material in the strong axis direction, causing higher-order mode buckling in the strong axis direction. To prevent this reduction in strength in the strong axis direction, spacers shorter than the slits are inserted into the slits. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6445862 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the buckling restraint brace described in Patent Document 1, by providing slits on the wide surface of the core material and inserting spacers into the slits, it is possible to adjust the axial force of the core material while suppressing a decrease in strength in the strong axis direction.

[0007] In a configuration in which a slit is formed in the broad surface of a core material and a separately manufactured, relatively short spacer is inserted into the slit, the longitudinal length of the slit is made longer than the spacer to prevent the spacer from interfering with the predetermined compressive strain in the longitudinal direction of the core material due to the axial force (compression) acting during an earthquake. However, when the slit is compressed longitudinally and higher-order mode buckling occurs, there is a risk that the spacer will fall out of the slit due to its own weight. Another issue is that when higher-order mode buckling occurs along the core material's strong axis, the spacer may be biased toward one end of the slit, widening the gap on the other side of the slit and creating an area that is not stiffened by the spacer.

[0008] The present invention was made in consideration of the above-mentioned problems, and aims to provide a buckling-restrained brace that can prevent components from falling off or areas that cannot be stiffened when the core material deforms, while enjoying the same effects as the conventional structure in which spacers are inserted into slits in the core material, such as adjusting the axial force of the core material and preventing a decrease in strength in the strong axis direction. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the buckling restrained brace according to the present invention is as follows: A buckling restrained brace having a steel plate-shaped core member and a pair of restraint members made of square steel pipes arranged so as to face two wide surfaces of the core member, a first unit and a second unit, which form an axial force adjusting means for the core material, are provided on the wide surface of the core material with a gap therebetween in the longitudinal direction of the core material; the first unit includes one through hole and two notches communicating with the through hole and extending in the longitudinal direction of the core material on one side of the through hole; The second unit is characterized by having one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core material on both the left and right sides of the through hole.

[0010] According to this aspect, in a buckling restraint brace in which the two wide faces of a steel plate-shaped core material are restrained by a pair of restraint members made of square steel pipes, a first unit and a second unit, which form the axial force adjustment means of the core material, are arranged on the wide faces of the core material with a gap between them, and the first unit has one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core material on one side of the through hole, and the second unit has one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core material on both the left and right sides of the through hole, respectively.As a result, the area inside the two notches becomes a spacer, and this spacer is the core material itself and is not inserted into a slit, so the through holes and multiple notches can both adjust the axial force of the core material and prevent a decrease in strength in the strong axis direction of the core material, while eliminating problems such as the occurrence of an unstiffened area due to spacer detachment or spacer movement.

[0011] In this way, a virtual slit is formed in the core material by a pair of cuts, and within this virtual slit, a virtual spacer formed by the core material itself is arranged, rather than a spacer that is manufactured separately as in the conventional case.

[0012] Furthermore, compared to the series of manufacturing methods that involve machining a slit in the wide surface of the core material, separately manufacturing a spacer, and inserting the spacer into the slit, this method only requires drilling (cutting out) a through hole in the wide surface of the core material, for example by laser processing, and machining two notches that connect to the through hole, thereby significantly improving manufacturing efficiency.

[0013] There are two types of structures: one in which an unbonded material is interposed between the core material and the restraining material, and one in which no unbonded material is interposed (an unbonded material-less structure). In the structure in which an unbonded material is interposed, the unbonded material is formed from an elastic material with deformability, such as butyl rubber. By interposing this unbonded material between the wide surface of the core material and the restraining material, the thickness of the unbonded material serves as a clearance, allowing higher-order mode buckling to occur within this clearance when the core material is subjected to a compressive force. On the other hand, in the structure in which no unbonded material is interposed, a gap is provided between the core material and the restraining material, allowing the gap to absorb higher-order mode buckling of the core material.

[0014] Another aspect of the buckling restrained brace according to the present invention is: The device is characterized in that at least one of the first unit and the second unit is provided in plurality.

[0015] According to this aspect, by providing multiple first units and / or second units, multiple peaks can be effectively restrained during higher-order mode buckling in the strong axis direction of the core material, and this can solve the problem that when design strain is absorbed by, for example, a single through-hole, the longitudinal length of the through-hole becomes large, leading to the occurrence of an unstiffened region. Here, "providing multiple first units and / or second units" includes a configuration having one first unit and multiple second units, a configuration having multiple first units and one second unit, and a configuration having multiple first units and multiple second units.

[0016] Another aspect of the buckling restrained brace according to the present invention is: The gap is present between a corresponding pair of notches among the two notches extending from adjacent left and right first units, or adjacent left and right second units, or adjacent left and right first and second units, and the other corresponding pair of notches is continuous without the gap.

[0017] According to this aspect, for example, between adjacent first and second units, or between adjacent first units, there is a gap between a corresponding pair of two notches extending from the left and right, and the other corresponding pair of notches is continuous without any gap, so that the two units can be connected to the core material with only one gap.

[0018] Another aspect of the buckling restrained brace according to the present invention is: In the planar view shape of the through hole of the first unit, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch has a second curvature that is convex toward the first curvature.

[0019] According to this aspect, in the planar shape of the through hole of the first unit, the contour on the other side where there is no notch has a curvature (first curvature), which can prevent a stress concentration region from occurring around the contour on the other side of the through hole. For example, if the contour on the other side where there is no notch has a rectangular shape with two corners, the areas around these corners become a stress concentration region, which may cause localized damage.

[0020] Furthermore, in the planar shape of the through hole of the first unit, the contour on the other side without the notch has a first curvature, and the contour on one side with the notch has a second curvature that is convex toward the first curvature, i.e., the contours of both the left and right end faces (both longitudinal end faces) of the through hole have convex curvatures in the same direction, so that when the core material is compressed in the longitudinal direction, the contour on one side (second curvature) fits into the contour on the other side (first curvature) of the through hole, suppressing mutual interference between the two and ensuring free (design) compressive strain of the core material. Here, from the perspective of manufacturing efficiency, it is preferable that the first and second curvatures be processed to have the same radius of curvature.

[0021] Another aspect of the buckling restrained brace according to the present invention is: In the planar view shape of the through hole of the first unit, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch is a straight line perpendicular to the longitudinal direction.

[0022] According to this aspect, in the planar shape of the through hole of the first unit, the contour on the other side where there is no notch has a first curvature, which makes it possible to prevent a stress concentration region from occurring around the contour on the other side of the through hole, as described above. Also, because the contour on the one side where there is a notch is linear and perpendicular to the longitudinal direction, this aspect also prevents mutual interference between the contour on the other side of the through hole (first curvature) and the contour on one side (linear and perpendicular to the longitudinal direction) when the core material is compressed in the longitudinal direction. This ensures free (design) compressive strain of the core material. In addition, because the contour on one side is linear, production efficiency can be improved compared to an aspect in which the contours on both sides have curvatures.

[0023] Another aspect of the buckling restrained brace according to the present invention is: The through-hole in the second unit has a rectangular shape in plan view, and two of the notches extend from each of the left and right straight lines of the rectangle that are perpendicular to the longitudinal direction.

[0024] According to this embodiment, the planar shape of the through hole in the second unit is rectangular, and the left and right contours of the rectangle are straight lines perpendicular to the longitudinal direction. Therefore, when the core material is compressed in the longitudinal direction, mutual interference between the left and right contours of the through hole is suppressed, and free (design) compression strain of the core material can be guaranteed. In addition, since the entire contour of the through hole, including the left and right contours, is formed by straight lines, the manufacturing efficiency of the through hole is improved.

[0025] In another aspect of the buckling restrained brace according to the present invention, A pair of joining plates are fixed to both ends of the core material, and are joined to other members perpendicular to the wide surfaces, a reinforcing plate is fixed to the pair of joining plates, and an end of the restraint material is accommodated in a space formed by the wide surface, the pair of joining plates, and the reinforcing plate; A pair of stiffeners connects both sides of the pair of restraint members on the sides of the core member, The core material is surrounded by the pair of restraining materials and the pair of stiffening materials.

[0026] According to this aspect, a pair of connecting plates perpendicular to the wide faces are fixed to both ends of the core member, and a reinforcing plate is fixed to the pair of connecting plates. The ends of the restraint members are accommodated in the space formed by the wide faces, the pair of connecting plates, and the reinforcing plate, resulting in a buckling-restrained brace with a high-strength end structure. Here, examples of other components to which the connecting plates are attached include connecting jigs such as brackets and gusset plates that extend into the structural surface from corners of a building frame. Furthermore, if the ends of the core member are webs, the pair of connecting plates perpendicular to the webs become a pair of flanges.

[0027] Furthermore, by connecting both sides of the pair of restraining members to the sides of the core member, deformation of the core member in the width direction (strong axis direction) can be restrained by the stiffening members.

[0028] Furthermore, when the buckling restrained brace according to the present invention has an unbonded material, an insert plate may be interposed between the unbonded material and the restraining material. In this configuration, by interposing an insert plate, for example made of steel, between the unbonded material and the restraining material, the pressing force caused by higher-order mode buckling in the weak axis direction of the core material acts directly on the restraining material, effectively preventing localized failure of the restraining material. [Effects of the Invention]

[0029] As can be understood from the above explanation, the buckling restraint brace of the present invention provides the same benefits as the conventional structure in which spacers are inserted into slits in the core material, such as adjusting the axial force of the core material and preventing a decrease in strength in the strong axis direction, while preventing components from falling out or areas that cannot be stiffened when the core material deforms. [Brief explanation of the drawings]

[0030] [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. 1 is a longitudinal cross-sectional view of a buckling restrained brace according to an embodiment, taken in a direction perpendicular to the axis. [Figure 4] FIG. 2 is a plan view of an example of a core material. [Figure 5A] 10 is an enlarged plan view of a portion of the through-hole and two notches of the first unit in the core material, showing the state of the core material before and after compression. FIG. [Figure 5B] 10A and 10B are enlarged plan views of another example of a through-hole of a first unit in a core material and a portion of two notches, showing the states of the core material before and after compression. [Figure 5C] 10 is a partially enlarged plan view of the through-hole and two notches on the left and right sides of the second unit in the core material, showing the state of the core material before and after compression. FIG. [Figure 6] FIG. 10 is a plan view of another example of the core material. [Figure 7] FIG. 10 is a plan view of yet another example of a core material. [Figure 8] FIG. 10 is a plan view of yet another example of a core material. [Figure 9A] FIG. 10 is a schematic diagram of a longitudinal cross section of a buckling restrained brace taken in a direction perpendicular to the axis, illustrating the state in which a pressing force acts from the core material to the restraining material during higher-order mode buckling. [Figure 9B] FIG. 10 is a schematic diagram of a vertical cross section of a buckling restrained brace taken along the axial direction, illustrating the state in which a pressing force acts from the core material to the restraining material during higher-order mode buckling. DETAILED DESCRIPTION OF THE INVENTION

[0031] 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.

[0032] [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 9. Here, Figure 1 is an exploded perspective view of an example of a buckling restrained brace according to an embodiment, Figure 2 is a perspective view of an example of a buckling restrained brace according to an embodiment, and Figure 3 is a longitudinal cross-sectional view of the buckling restrained brace according to an embodiment in a direction perpendicular to the axis. Also, Figure 4 is a plan view of an example of a core material, Figure 5A is an enlarged view of a portion of a through hole and two notches of a first unit in the core material, showing the state of the core material before and after compression, and Figure 5C is an enlarged view of a portion of a through hole and two notches on each side of a second unit in the core material, showing the state of the core material before and after compression.

[0033] The buckling restrained brace 100 has a core material 10, a pair of restraining members 30 arranged to face the two wide surfaces 10a of the core material 10, and unbonded members 20 interposed between the core material 10 and the restraining members 30. In addition to the illustrated example, a configuration in which an insert plate made of a steel plate is interposed between the unbonded members 20 and the restraining members 30 may also be used. An unbonded member-less configuration without the unbonded members 20 is also possible, in which a gap of approximately the same thickness as the unbonded members 20 is provided between the core material 10 and the restraining members 30.

[0034] 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.

[0035] The core material 10 is formed from a long, thin steel plate, and has a narrow width portion 11 at the center of its longitudinal direction where the width of the wide surface 10a is relatively narrow, and a wide width portion 12 at the end of its longitudinal direction where the width of the wide surface 10a is relatively wide.

[0036] By having the core material 10 have a narrow width portion 11 at the center in the longitudinal direction and wide width portions 12 at the end portions in the longitudinal direction, the narrow width portion 11 at the center can be made into a region that is easily plasticized, and further, the plasticized region can be limited to the narrow width portion 11 at the center. Here, the boundary region between the narrow width portion 11 and the wide width portion 12 of the core material 10 has a shape in which the width gradually increases in a curved manner from the narrow width portion 11 to the wide width portion 12, preventing the occurrence of localized stress concentration areas due to a sudden change in width.

[0037] At the center position of the narrow width portion 11 of the core material 10, a cylindrical protrusion 14 made of steel protrudes from the two wide width surfaces 10a of the narrow width portion 11. The protrusion 14 is joined to the wide width surfaces 10a of the narrow width portion 11 by welding or the like.

[0038] Additionally, a first unit 15A and a second unit 15B are provided in the narrow portion 11 of the core material 10 with a gap between them in the longitudinal direction of the core material 10. The first unit 15A has one through hole 16A and two notches 17 that communicate with the through hole 16A and extend in the longitudinal direction of the core material 10 on one side of the through hole 16A (the right side in the illustrated example). On the other hand, the second unit 15B has one through hole 16B and two notches 17 that communicate with the through hole 16B and extend in the longitudinal direction of the core material 10 on both the left and right sides of the through hole 16B. These units 15A and 15B will be described in detail below.

[0039] A pair of joining plates 13 made of steel plates are joined by welding or the like to the wide portions 12 at both ends of the core material, and are joined to other members perpendicular to the wide surfaces 10a.

[0040] The wide portion 12 and the connecting plate 13 are provided with bolt holes 12a and 13a, respectively, which are aligned with the bolt holes of connecting jigs (other components) such as brackets and gusset plates that protrude into the structural surface from corners of the building frame (not shown), and are bolted together.

[0041] Reinforcing plates 18 made of steel plates are joined to the pair of connecting plates 13 by welding or the like, and the ends of the restraint members 30 are accommodated in the space formed by the wide portion 12 of the core member 10, the pair of connecting plates 13, and the reinforcing plates 18. The reinforcing plates 18 prevent the ends of the core member 10 of the restraint members 30 from opening in the weak axis direction, thereby preventing a decrease in strength or damage to the ends of the buckling restrained brace 100.

[0042] The unbonded material 20 is inserted between the narrow portion 11 of the core material 10 and the restraint material 30, and with the thickness of the unbonded material 20 as a clearance, when the building frame is deformed, a compressive force acts on the core material 10, causing higher-order mode buckling (wavy deformation) in the out-of-plane direction (weak axis direction) in the narrow portion 11.

[0043] An elastic material such as butyl rubber is used as the unbond material 20. Furthermore, a projection hole 20a into which the projection 14 of the core material 10 fits is provided at the center position in the longitudinal direction of the unbond material 20.

[0044] The restraint material 30 is formed from a square steel pipe that is rectangular in cross section, and the side surface corresponding to the long side of the rectangle abuts against the unbonded material 20. The side surface of the restraint material 30 that abuts against the unbonded material 20 also has projection holes 30a into which the projections 14 of the core material 10 fit. Note that, although each corner portion of the square steel pipe 30 in the illustrated example is not a right angle but forms a curved surface (R portion), each corner portion may also be a right angle.

[0045] On the sides of the core material 10, both sides (sides corresponding to the short sides of the rectangle) of the pair of restraint materials 30 are connected by welding or the like to a pair of stiffeners 50 made of steel plates, and the core material 10 is surrounded by the pair of restraint materials 30 and the pair of stiffeners 50.

[0046] Next, the axial force adjusting means provided on the core material will be described with reference to FIGS.

[0047] The example shown in Figure 4 is a configuration in which two first units 15A are provided on each side of the narrow portion 11 of the core material 10, and one second unit 15B is arranged between these two first units 15A with a gap G between them.

[0048] The first unit 15A has one through hole 16A and two notches 17 on the right side of the through hole 16A that communicate with the through hole 16A. On the other hand, the second unit 15B has one through hole 16B and two notches 17 that communicate with the left and right sides of the through hole 16B, respectively.

[0049] In the illustrated example, two first units 15A and one second unit 15B are provided on the left and right sides of the center in the narrow width portion 11 of the core material 10, and a total of four first units 15A and two second units 15B form the axial force adjustment means of the core material 10.

[0050] A gap G is provided between adjacent first units 15A and second units 15B, or between two first units 15A, and the first units 15A and second units 15B are not continuous with each other.

[0051] On each of the left and right sides of the narrow width portion 11 of the core material 10, the two first units 15A have the same left-right position of the through hole 16A relative to the two notches 17 (in the illustrated example, the through hole 16A is located on the left side). Here, both of the two first units 15A on each of the left and right sides of the core material 10 may have the two notches 17 communicating with the through hole 16A on the left side of the through hole 16A (the through hole 16A may be located on the right side).

[0052] The through holes 16A and 16B are both hollowed out by, for example, laser processing in the longitudinal direction of the core material 10 to have predetermined widths t1 and t2.

[0053] The widths t1 and t2 of the through holes 16A and 16B are set to a length between, for example, a length corresponding to the design strain as a lower limit and a buckling length (the length between peaks) when higher-order mode buckling occurs in the strong axis direction of the core material 10 as an upper limit. By setting the widths t1 and t2 of the through holes 16A and 16B in this manner, the design strain can be absorbed by the through holes 16A and 16B, and a stiffening effect can be ensured when higher-order mode buckling occurs in the strong axis direction of the core material 10.

[0054] 4 and 5A, the planar shape of through hole 16A of first unit 15A has a contour on the other side (the left side in the illustrated example) where there are no two notches 17, which has a first curvature 16a, and a contour on the one side (the right side in the illustrated example) where there are two notches 17, which has a second curvature 16b that is convex toward first curvature 16a. Here, it is preferable from the standpoint of manufacturing efficiency that both first curvature 16a and second curvature 16b have the same radius of curvature, but the radii of curvature may also be different.

[0055] In the narrow portion 11 of the core material 10, a through hole 16A of the first unit 15A that absorbs the design strain of the core material 10 is provided, and two notches 17 that communicate with this through hole 16A are provided extending in the longitudinal direction of the core material 10. As a result, the two notches 17 form a virtual slit in the core material 10 for adjusting axial force, and the area sandwiched between the two notches 17 is the core material 10 itself, but also forms a virtual spacer S inserted into the virtual slit. Furthermore, the ends of the two notches 17 on the opposite side from the through hole 16A (the right end in the illustrated example) are continuous with another core material 10, so the spacer S sandwiched between the two notches 17 will not fall off from other areas of the core material 10.

[0056] Therefore, the through hole 16A and the two notches 17 can adjust the axial force of the core material 10 and suppress a decrease in strength in the strong axis direction of the core material 10, while eliminating problems such as the falling off of the spacer S or the creation of areas that cannot be stiffened due to the movement of the spacer S.

[0057] Furthermore, compared to the conventional series of manufacturing methods in which a slit is machined in the narrow portion of the core material, a spacer is manufactured separately, and the spacer is inserted into the slit, in the illustrated example, it is only necessary to open a through hole 16A in the narrow portion 11 of the core material 10, for example by laser processing, and then laser process two notches 17 that communicate with the through hole 16A, thereby significantly improving manufacturing efficiency.

[0058] 5A, in the planar shape of through hole 16A, the outline on the other side (the left side in the illustrated example) where there is no notch 17 has first curvature 16a, which can prevent a stress concentration region from occurring around the outline on the other side of through hole 16. For example, if the outline on the other side where there is no notch 17 has a rectangular shape with two corners, the areas around these corners become a stress concentration region, and localized breakage is likely to occur.

[0059] Furthermore, in the planar view shape of the through hole 16A, the contour on the other side where there is no notch 17 has a first curvature 16a, and the contour on one side where there is notch 17 (the right side in the illustrated example) has a second curvature 16b that is convex toward the first curvature 16a.Therefore, when the core material 10 is compressed longitudinally in the X1 direction, the second curvature 16b on one side fits into the first curvature 16a on the other side of the through hole 16, suppressing mutual interference between the two and ensuring free compression strain of the core material 10.

[0060] Here, as shown in Figure 5B, in the planar view shape of the through hole 16A' forming the unit 15A', the contour on the other side where there is no notch 17 may have a first curvature 16a, and the contour on the one side where there is notch 17 may have a straight line 16c perpendicular to the longitudinal direction of the core material 10.

[0061] In this configuration, the outline on one side where the incision 17 is located is linear and perpendicular to the longitudinal direction of the core material 10, so that even in this configuration, when the core material 10 is compressed longitudinally in the X1 direction, mutual interference between the first curvature 16a of the through hole 16A' and the straight line 16c on one side is suppressed, ensuring free compressive strain of the core material 10. In addition to this, because the outline on one side is straight line 16c, production efficiency can be improved compared to a configuration in which the outlines on both sides have curvatures.

[0062] On the other hand, as shown by the solid lines in FIGS. 4 and 5C, through-hole 16B of second unit 15B has a rectangular shape in plan view, and both left and right contours of through-hole 16B are straight lines 16d that are perpendicular to the longitudinal direction.

[0063] In the narrow portion 11 of the core material 10, a through hole 16B of the second unit 15B that absorbs the design strain of the core material 10 is provided, and two left and right notches 17 that communicate with this through hole 16B are provided extending in the longitudinal direction of the core material 10, so that the two left and right notches 17 form a virtual slit in the core material 10 for adjusting axial force, and the area sandwiched between the two left and right notches 17 forms a virtual spacer S inserted into the virtual slit, while being the core material 10 itself. Furthermore, the ends of the two left and right notches 17 opposite the through hole 16B are continuous with another core material 10, so the two spacers S sandwiched between the two left and right notches 17 will not fall off from other areas of the core material 10.

[0064] Furthermore, in the second unit 15B, it is only necessary to open a through hole 16B in the narrow portion 11 of the core material 10, for example by laser processing, and then laser process two notches 17 on the left and right that communicate with the through hole 16B, thereby significantly improving production efficiency.

[0065] Furthermore, since the planar shape of the through hole 16B is rectangular and both left and right contours are straight lines 16d, when the core material 10 is compressed longitudinally in the X2 direction, mutual interference between the left and right straight lines 16d of the through hole 16B is suppressed, ensuring free compression strain of the core material 10.

[0066] 6 shows a configuration in which the left-right positions of the through holes 16A relative to the two notches 17 are reversed in the two first units 15A on each side of the core material 10A (in the illustrated example, the through hole 16A in the left first unit 15A is positioned on the left side, and the through hole 16A in the right first unit 15A is positioned on the right side). In the core material 10A as well, a virtual slit is formed by each pair of notches 17 in each first unit 15A and second unit 15B, and a virtual spacer S formed by the core material 10A itself is provided within the virtual slit.

[0067] 7 shows a configuration in which, on each of the left and right sides of core material 10B, two of the four gaps G between the left and right notches 17 of the central second unit 15B and the two notches 17 of the first unit 15A on either side thereof are eliminated, and the corresponding notches 17 of the three first units 15A and second unit bodies 15B are continuous with each other. In the illustrated example, only two gaps G exist above the three first units 15A and second unit bodies 15B. However, a configuration in which one of the two upper gaps G is eliminated to connect the notches 17 with each other, and the three first units 15A and second unit bodies 15B are continuous with the surrounding core material 10B by only one gap G may also be used.

[0068] Even in this form, there are a total of two gaps G between the corresponding notches 17 of the first unit 15A and the second unit 15B, so that a virtual spacer S is formed between each pair of notches 17, and these are integrated with the area outside the notches 17 in the core material 10B via the gap G, thereby preventing the virtual spacer S from falling out of the core material 10C.

[0069] The core 10C shown in FIG. 8 has a configuration including one first unit 15A and a pair of second units 15B on the left and right of the first unit 15A shown in FIG.

[0070] In this configuration, the number of first units 15A and second units 15B is as small as possible, and therefore the manufacturing efficiency of core material 10C is further improved compared to core material 10, 10A, and 10B.

[0071] Even in this form, the ends of the notches 17 of the first unit 15A and the second unit 15B are connected to other areas of the core material 10C, thereby preventing the virtual spacer S sandwiched between the pair of notches 17 from falling out of the core material 10C.

[0072] As described above, the buckling restraint brace 100, which is equipped with core materials 10, 10A, 10B, and 10C, provides the same benefits as the conventional structure in which spacers are inserted into slits in the core material, such as adjusting the axial force of the core material and preventing a decrease in strength in the strong axis direction, while preventing problems such as the spacers falling out when the core materials 10, 10A, 10B, and 10C deform, or problems such as the creation of areas in the slits that cannot be stiffened.

[0073] Next, with reference to FIG. 9, a description will be given of the buckling of a higher mode occurring in the weak axis direction of the core material 10. FIG.

[0074] The buckling-restrained brace 100 is incorporated into a building frame by bolting its ends to connecting jigs installed at corners of the building frame. When the building frame deforms during an earthquake, external forces such as horizontal forces during the earthquake enter the ends of the buckling-restrained brace 100 through the connecting jigs, and the external force is transmitted as a compressive force N from the ends of the core material 10 to the entire area, causing plastic deformation throughout the entire core material 10, thereby demonstrating its energy absorption performance during an earthquake. In other words, when compressive force N acts on the core material 10, higher-order mode buckling (wave-like deformation) occurs throughout the entire core material 10 in its weak axis direction, causing the entire core material 10 to buckle as evenly as possible, thereby enabling the buckling-restrained brace 100 to demonstrate its overall plastic deformation performance.

[0075] 9B, a compressive force N acting on core material 10 causes higher-order mode buckling, and the peaks of the wave-like deformation caused by buckling come into contact with restraining material 30, applying a compressive force Q to restraining material 30. Therefore, the local yield strength of restraining material 30 is set so that the locally acting compressive force Q does not cause localized failure.

[0076] 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.

[0077] For example, of the first and second units that form the axial force adjusting means of the core material, only the first unit may be provided.

[0078] Specifically, an example is a buckling restraint brace having only a first unit, which is a buckling restraint brace having a steel plate-shaped core member and a pair of restraint members made of square steel pipes arranged opposite the two wide faces of the core member, and the wide face of the core member has one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core member on one side of the through hole, and the through hole and the notches form the axial force adjustment means of the core member.

[0079] In a configuration having only this first unit, there may be a configuration in which a plurality of first units each consisting of one through-hole and two notches are provided with gaps in the longitudinal direction.

[0080] In addition, in a configuration having only first units, there is also a configuration in which the plurality of first units have through holes with the same left and right positions relative to the cutouts.

[0081] In addition, in a configuration having only first units, there is also a configuration in which the first units are provided with the left and right positions of the through holes with respect to the cutouts reversed.

[0082] In addition, in a form having only the first unit, there may be a form in which, of the two notches extending from the left and right, there is a gap between a corresponding pair of the notches, and the other corresponding pair of the notches are continuous without any gap.

[0083] In addition, in a form having only the first unit, in the planar shape of the through hole, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch has a second curvature that is convex toward the first curvature.

[0084] Furthermore, in a form having only the first unit, in the planar view shape of the through hole, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch is a straight line perpendicular to the longitudinal direction.

[0085] On the other hand, of the first and second units that form the axial force adjusting means of the core material, only the second unit may be provided.

[0086] Specifically, an example is a buckling restraint brace having only a second unit, which is a buckling restraint brace having a steel plate-shaped core member and a pair of restraint members made of square steel pipes arranged opposite the two wide faces of the core member, and the wide face of the core member has one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core member on either side of the through hole, the through hole and the notches forming an axial force adjustment means for the core member.

[0087] In a configuration having only this second unit, there may be a configuration in which a plurality of second units each consisting of one through-hole and two notches on each side are provided with gaps in the longitudinal direction.

[0088] In addition, in a configuration having only the second unit, there may be a configuration in which, of the two notches extending from the adjacent left and right second units, there is a gap between one corresponding pair of the notches, and the other corresponding pair of the notches are continuous without a gap.

[0089] Furthermore, in a configuration having only the second unit, the through-hole may have a rectangular shape in plan view, with two slits extending from each of the left and right straight lines of the rectangle that are perpendicular to the longitudinal direction. [Explanation of symbols]

[0090] 10: Core material 10a: Wide surface 11: Narrow section 12: Wide section 12a: Bolt hole 13: Joint plate 13a: Bolt hole 14: Protrusion 15A, 15A': 1st unit 15B: 2nd unit 16A, 16B: Through hole 16a: 1st curvature 16b: 2nd curvature 16c,16d: Straight line 17: Cut 18: Reinforcement plate 20: Unbonded material 20a:Protrusion hole 30: Restraint material (square steel pipe) 30a:Protrusion hole 50: Stiffener 100: Buckling restrained brace S: Spacer (virtual spacer) G: Gap N: Axial force (compressive force) Q: Pressing force

Claims

1. A buckling restrained brace having a steel plate-shaped core member and a pair of restraint members made of square steel pipes arranged so as to face two wide surfaces of the core member, a first unit and a second unit, which form an axial force adjusting means for the core material, are provided on the wide surface of the core material with a gap therebetween in the longitudinal direction of the core material; the first unit includes one through hole and two notches communicating with the through hole and extending in the longitudinal direction of the core material on one side of the through hole; A buckling restraint brace, characterized in that the second unit has one through hole and two notches that communicate with the through hole and extend in the longitudinal direction of the core material on both the left and right sides of the through hole.

2. The buckling restraint brace according to claim 1 , wherein at least one of the first unit and the second unit is provided in plurality.

3. 3. The buckling restraint brace according to claim 1 or 2, characterized in that, of the two notches extending from adjacent left and right first units, or adjacent left and right second units, or adjacent left and right first units and second units, the gap is present between a corresponding pair of the notches, and the other corresponding pair of the notches is continuous without the gap.

4. 4. A buckling restraint brace as described in any one of claims 1 to 3, characterized in that, in a planar view of the through hole of the first unit, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch has a second curvature that is convex toward the first curvature.

5. 4. A buckling restraint brace as described in any one of claims 1 to 3, characterized in that, in a planar view of the through hole of the first unit, the contour on the other side where there is no notch has a first curvature, and the contour on the one side where there is the notch is a straight line perpendicular to the longitudinal direction.

6. 6. A buckling restraint brace as described in any one of claims 1 to 5, characterized in that the planar shape of the through hole in the second unit is rectangular, and two of the notches extend from each of the left and right lines of the rectangle that are perpendicular to the longitudinal direction.

7. A pair of joining plates are fixed to both ends of the core material, and are joined to other members perpendicular to the wide surfaces, a reinforcing plate is fixed to the pair of joining plates, and an end of the restraint material is accommodated in a space formed by the wide surface, the pair of joining plates, and the reinforcing plate; A pair of stiffeners connects both sides of the pair of restraint members on the sides of the core member, 7. The buckling restrained brace according to claim 1, wherein the core member is surrounded by the pair of restraining members and the pair of stiffening members.

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