Buckling restraint brace

Abstract

To provide a buckling restraint brace that can prevent components from falling off or the occurrence of regions that cannot be stiffened when the core material is deformed, while maintaining the same effects as those of a conventional structure in which a spacer is inserted into a slit provided in the core material, such as adjusting the axial force of the core material and suppressing the pressing force in the strong axis direction.SOLUTION: A buckling restraint brace 100 includes a steel plate-shaped core material 10, a pair of restraint materials 30 made of square steel pipes arranged opposite two wide surfaces 10a of the core material 10, and an unbonded material 20 interposed between the core material 10 and the restraint materials 30. The wide surface 10a of the core material 10 is provided with one through hole 16 and two notches 17 that communicate with the through hole 16 and extend in the longitudinal direction of the core material 10 on one side of the through hole 16. The through hole 16 and the notches 17 form axial force adjustment means of the core material 10, and both of the two notches 17 extend to one of wide portions 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Buckling-restrained braces with buckling prevention measures have been used as braces that form building frames (column-beam frames, roof frames, etc.). Buckling-restrained braces come in a variety of stiffening forms, including a form in which the periphery of a steel core is stiffened only with steel plates, a form in which the periphery of a steel core is stiffened with RC (Reinforced Concrete), and a form in which the periphery of a steel core is covered with steel and mortar.

[0003] Here, 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 does not cause local destruction in the restraining members that receive a pressing force from the core member. Specifically, the buckling-restrained brace includes a core member that has joints at both ends of the plate-like portion for joining to other members, and restraining members arranged opposite each face perpendicular to the weak axis direction of the plate-like portion.

[0004] In this buckling restrained brace, slits are provided on the wide surface of the core material, and these slits are used to adjust the axial force (or strength) acting on the core material. When the core material receives an axial force (compressive force), higher-order mode buckling effectively occurs in the weak axis direction of the core material. However, by providing slits on the wide surface, the moment of inertia in the strong axis direction of the core material decreases, and there is a trade-off in that the compressive force in the strong axis direction increases. To suppress this compressive force in the strong axis direction, a spacer shorter than the slit is inserted into the slit. [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 suppress the compressive force in the strong axis direction while adjusting the axial force of the core material.

[0007] In a configuration in which a slit is provided on the broad surface of the core material and a relatively short spacer that is separately manufactured is inserted into the slit, the longitudinal length of the slit is made longer than the spacer to prevent the spacer from hindering a predetermined compressive strain in the longitudinal direction of the core material caused by the axial force (compressive force) acting during an earthquake. However, when the slit is compressed in the longitudinal direction and buckling in a higher mode occurs, there is a risk that the spacer will fall out of the slit under its own weight. In addition, there is also a problem that when buckling in a higher mode in the strong axis direction of the core material occurs, the spacer is biased to one end side of the slit, and the gap on the other side of the slit becomes large, resulting in an area that is not stiffened by the spacer.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a buckling restraint brace that can prevent components from falling off or areas that cannot be stiffened when the core material deforms, while achieving 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 suppressing the pressing force in the strong axis direction. [Means for solving the problem]

[0009] In order to achieve the above object, one aspect of the buckling restraint brace according to the present invention is as follows: A buckling restraint brace having a steel plate-shaped core material and a pair of restraint members made of square steel pipes arranged to face two wide surfaces of the core material, The core material has a narrow portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide portion at an end side in the longitudinal direction, where the width of the wide surface is relatively wide, a 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 are provided on the wide surface of the narrow portion, the through hole and the notches forming an axial force adjustment means for the core material; The two cuts each extend to one of the wide portions.

[0010] According to this aspect, in a buckling restraint brace in which the two wide surfaces of a steel plate-shaped core material are restrained by a pair of restraining members made of square steel pipes, the wide surface of the core material is provided with 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 through hole and two notches form an axial force adjustment means for the core material, so that the area inside the two notches becomes a spacer, and since this spacer is the core material itself and is not inserted into a slit, the through hole and two notches can both adjust the axial force of the core material and suppress the pressing force in the strong axis direction of the core material, while eliminating problems such as the falling off of the spacer or the creation of an area that cannot be stiffened due to the spacer moving.

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

[0012] Furthermore, compared to a 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, it is only necessary to open (hollow out) a through hole in the wide surface of the core material, for example by laser processing, and then machine two notches that lead to the through hole, thereby dramatically improving manufacturing efficiency.

[0013] Furthermore, the core material has a narrow portion at the center in the longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion at the end in the longitudinal direction where the width of the wide surface is relatively wide, and each of the two cuts extends to one of the wide portions, so that, for example, the ends of the two linear cuts are located in the narrow portions that are plastic deformation regions, causing the cross-sectional rigidity of the core material to change suddenly, and when an external force during an earthquake is input to the core material, the core material is damaged near the ends of the cuts that may be the points at which the cross-sectional rigidity changes suddenly. In other words, since the wide portions do not or are less likely to plastically deform in comparison with the narrow portions that plastically deform during an earthquake, the end of the cut is located in the wide portion, and therefore there is no risk of the core material being damaged near the end of the cut.

[0014] In another embodiment, even if the ends of the two cuts have a linear shape that gradually approaches the other cut, the cross-sectional rigidity of the core material can be prevented from suddenly changing at the ends of the two linear cuts. However, in this embodiment, if the distance between the two cuts is small, there may be a case where the margin for making the ends of both cuts linearly approach the other cut cannot be secured, and in such a case, this embodiment cannot be adopted. In contrast, in this embodiment, the cuts are extended to the wide portion, so that damage to the core material near the ends of the cuts can be prevented regardless of the size of the distance between the two cuts.

[0015] Here, if the width of the wide surface changes suddenly from the narrow portion to the wide portion, this change point becomes a structurally weak portion, and it may break first during an earthquake, which may hinder the earthquake energy absorption due to plastic deformation in the entire narrow portion or at a desired position. Therefore, it is preferable to provide a width transition region in which the width of the wide surface gradually increases in a tapered or curved shape from the narrow portion to the wide portion, and such a width transition region is considered to be included in the wide portion in this specification.

[0016] Between the core material and the restraining material, there is a form in which an unbond material is interposed, and a form without an unbond material. In the form with an unbond material interposed, the unbond material is formed of an elastic material having a deformation performance such as butyl rubber, or a mixture of a lubricant and a synthetic resin. By interposing the unbond material between the wide surface of the core material and the restraining material, it becomes possible to cause buckling of a higher mode within the clearance when the core material is subjected to a compressive force, with the thickness of the unbond material as a clearance. On the other hand, in the form without an unbond material, a gap is provided between the core material and the restraining material, and the gap can absorb buckling of a higher mode of the core material.

[0017] Another aspect of the buckling restraint brace according to the present invention is A buckling restraint brace having a steel plate-shaped core material and a pair of restraint members made of square steel pipes arranged to face two wide surfaces of the core material, The core material has a narrow portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide portion at an end side in the longitudinal direction, where the width of the wide surface is relatively wide, a through hole and two notches communicating with the through hole and extending in the longitudinal direction of the core material on both the left and right sides of the through hole are provided on the wide surface of the narrow portion, the through hole and the notches forming an axial force adjustment means for the core material; The two cuts on the left and right sides each extend to the wide portion on the left and right sides.

[0018] According to this aspect, in a buckling restraint brace in which the two wide surfaces of a steel plate-shaped core material are restrained by a pair of restraint members made of square steel pipes, the wide surface of the core material is provided with 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, and the through hole and the two notches on the left and right form an axial force adjustment means for the core material, so that the area inside the two notches on the left and right serves as a spacer, and since this spacer is the core material itself and is not inserted into a slit, the through hole and the two notches on the left and right allow for both adjustment of the axial force of the core material and suppression of the pressing force in the strong axis direction of the core material, while eliminating problems such as the spacer falling off or the occurrence of areas that cannot be stiffened due to the spacer moving.

[0019] Furthermore, the core material has a narrow width portion at the center of its longitudinal direction where the width of the wide surface is relatively narrow, and a wide width portion at the end sides of its longitudinal direction where the width of the wide surface is relatively wide, and both of the two left and right notches extend to the left and right wide portions, which are areas that do not undergo plastic deformation or are difficult to undergo plastic deformation when external forces are input to the core material during an earthquake.For example, the ends of the two straight notches are located in the narrow width portions, which are areas of plastic deformation, causing the cross-sectional rigidity of the core material to change suddenly, and it is possible to prevent the core material from being damaged near the ends of the notches, which may be the points of sudden change in cross-sectional rigidity during an earthquake.

[0020] Another aspect of the buckling restraint brace according to the present invention is Two units each including one through hole and two of the notches are provided with a gap in the longitudinal direction, Both of the two units are characterized in that the through hole is disposed on the central side of the narrow portion, and the two cuts extend to the wide portion.

[0021] According to the present embodiment, two units each consisting of one through hole and two notches are provided with a gap in the longitudinal direction, thereby effectively restraining multiple peaks that occur during higher-order mode buckling in the strong axis direction of the core material, thereby eliminating 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 creation of an area that cannot be stiffened.

[0022] Another aspect of the buckling restraint brace according to the present invention is 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 the notch is present has a second curvature that is convex toward the first curvature.

[0023] According to this aspect, in the planar shape of the through hole, the contour on the other side where there is no cut has a curvature (first curvature), so that it is possible to suppress the occurrence of a stress concentration region around the contour on the other side of the through hole. For example, if the contour on the other side where there is no cut has a rectangular shape with two corners, the periphery of these corners becomes a stress concentration region, and there is a concern of localized breakage.

[0024] Furthermore, in the planar shape of the through hole, 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 convex toward the first curvature, i.e., the contours of the left and right end faces (both longitudinal end faces) of the through hole both have a convex curvature 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 of the through hole (first curvature), suppressing mutual interference between the two and ensuring free (design) compression strain of the core material. Here, from the viewpoint of manufacturing efficiency, it is preferable that the first curvature and the second curvature are processed to have the same radius of curvature.

[0025] Another aspect of the buckling restraint brace according to the present invention is 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 straight and perpendicular to the longitudinal direction.

[0026] According to this embodiment, since the contour on the other side where there is no cut has a first curvature, it is possible to suppress the occurrence of a stress concentration region around the contour on the other side of the through hole, as described above. Also, since the contour on the one side where there is a cut has a straight line perpendicular to the longitudinal direction, this embodiment also suppresses mutual interference between the contour on the other side of the through hole (first curvature) and the contour on one side (straight line perpendicular to the longitudinal direction) when the core material is compressed in the longitudinal direction, and in addition, it is possible to guarantee free (design) compression strain of the core material. In addition, since the contour on one side is a straight line, it is possible to improve production efficiency compared to an embodiment in which the contours on both sides have curvature.

[0027] Another aspect of the buckling restraint brace according to the present invention is A pair of joining plates are fixed to both ends of the core material, and are joined to other members perpendicular to the wide surface, A reinforcing plate is fixed to the pair of joining plates, and an end of the restraining material is accommodated in a space formed by the wide surface, the pair of joining plates, and the reinforcing plate, A pair of stiffening members connects both sides of the pair of restraining 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.

[0028] According to this aspect, a pair of connecting plates perpendicular to the wide surface are fixed to both ends of the core material, a reinforcing plate is fixed to the pair of connecting plates, and the end of the restraining material is accommodated in the space formed by the wide surface and 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 members to which the connecting plates are joined include connecting jigs such as brackets and gusset plates that protrude into the structural surface from corners of the building frame. In addition, if the end of the core material is a web, the pair of connecting plates perpendicular to the web will be a pair of flanges.

[0029] In addition, by connecting both sides of the pair of restraining materials by a pair of stiffening materials on the sides of the core material, deformation of the core material in the width direction (strong axis direction) can be restrained by the stiffening materials.

[0030] The buckling restrained brace according to the present invention may also have an insert plate between the unbonded material and the restraining material. In this embodiment, by having an insert plate, for example made of steel, between the unbonded material and the restraining material, the pressing force caused by the 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. Effect of the Invention

[0031] As can be understood from the above explanation, the buckling restraint brace of the present invention provides 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 suppressing the compressive force in the strong axis direction, while preventing components from falling off or areas that cannot be stiffened when the core material deforms. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is an exploded perspective view of an example buckling restrained brace according to embodiments. [Diagram 2] FIG. 1 is a perspective view of an example of a buckling restrained brace according to embodiments. [Diagram 3] FIG. 2 is a longitudinal cross-sectional view of a buckling restraint brace according to an embodiment of the present invention 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] FIG. 2 is an enlarged plan view of a portion of the through hole and two notches in the core material, showing the state of the core material before and after compression. [Figure 5B] 13 is an enlarged plan view of another example of a through hole in a core material and a portion of two cuts, showing the state of the core material before and after compression. FIG. [Figure 6] FIG. 11 is a plan view of another example of the core material. [Figure 7] FIG. 13 is a plan view of yet another example of the core material. [Figure 8] 8 is an enlarged view of a portion of the through hole and two notches in the core material shown in FIG. 7, showing the states of the core material before and after compression. FIG. [Figure 9A] FIG. 13 is a schematic diagram of a vertical cross section of a buckling restraint brace in a direction perpendicular to the axis, illustrating the state in which a pressing force acts from the core material to the restraint material during higher-order mode buckling. [Figure 9B] FIG. 13 is a schematic diagram of a vertical cross section in the axial direction of a buckling restraint brace, illustrating the state in which a pressing force acts from the core material to the restraint material during higher-order mode buckling. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, a buckling restraint brace according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components are designated by the same reference numerals to avoid redundant description.

[0034] [Buckling restraint brace according to 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 a partially enlarged view of a through hole and two notches in the core material, showing the state of the core material before and after compression, and Figure 5B is a partially enlarged view of another example of a through hole and two notches in the core material, showing the state of the core material before and after compression.

[0035] The buckling restrained brace 100 has a core material 10, a pair of restraining materials 30 arranged to face two wide surfaces 10a of the core material 10, and an unbonded material 20 interposed between the core material 10 and the restraining material 30. In addition to the illustrated example, an insert plate made of a steel plate may be interposed between the unbonded material 20 and the restraining material 30. Also, an unbonded material-less form not including the unbonded material 20 may be used, in which a gap of approximately the same thickness as the unbonded material 20 is provided between the core material 10 and the restraining material 30.

[0036] It is preferable that the core material 10 be formed from a steel material with a low yield point, such as SN material (rolled steel material for architectural structures) or LYP material (very low yield point steel material). By using a core material 10 made from these materials, the yielding of the core material 10 results in good earthquake energy absorption.

[0037] 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.

[0038] 4, there is a width transition region 12A between the narrow width portion 11 and the wide width portion 12, where the width of the wide width surface gradually increases, but the width transition region 12A is considered to be included in the wide width portion 12. The width gradually increases in a curved shape from the narrow width portion 11 to the wide width portion 12 due to the width transition region 12A, thereby preventing the occurrence of localized stress concentration areas due to a sudden change in width.

[0039] Since the core material 10 has a narrow width portion 11 at the center of its longitudinal direction and a wide width portion 12 at each end of the longitudinal direction, the narrow width portion 11 at the center can be made into a region that is easily plasticized, and further, the plasticization region can be limited to the narrow width portion 11 at the center.

[0040] A cylindrical steel protrusion 14 protrudes from the two wide surfaces 10a of the narrow portion 11 at the center of the narrow portion 11 of the core material 10. The protrusion 14 is joined to the wide surfaces 10a of the narrow portion 11 by welding or the like.

[0041] Furthermore, a unit 15 is provided in the narrow portion 11 of the core material 10, the unit 15 having one through hole 16 and two notches 17 that communicate with the through hole 16 and extend in the longitudinal direction of the core material 10 on one side (the right side in the illustrated example) of the through hole 16. This unit 15 will be described in detail below.

[0042] 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 so as to be joined to other members perpendicular to the wide surfaces 10a.

[0043] The wide portion 12 and the connecting plate 13 are provided with bolt holes 12a, 13a, respectively, which are aligned with the bolt holes of connecting fixtures (other components) such as brackets and gusset plates that protrude into the structural surface from corners, etc. of the building frame (not shown), and are bolted together.

[0044] A reinforcing plate 19 made of a steel plate is joined to the pair of connecting plates 13 by welding or the like, and an end of the restraining material 30 is accommodated in the space formed by the wide portion 12 of the core material 10, the pair of connecting plates 13, and the reinforcing plate 19. The reinforcing plate 19 prevents the end of the core material 10 of the restraining material 30 from opening in the weak axis direction, and prevents a decrease in strength or damage to the end of the buckling restrained brace 100.

[0045] The unbonded material 20 is inserted between the narrow width 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 width portion 11.

[0046] The unbonded material 20 is formed of, for example, an elastic material such as butyl rubber, or a mixture of a lubricant and a synthetic resin. In the latter form, the lubricant can be a solid lubricant or a liquid lubricant. Examples of the solid lubricant include molybdenum disulfide (MoS2), graphite, and fluororesin (PTFE: polytetrafluoroethylene). By forming a solid lubricant film on the friction surface, direct contact of the friction surface material can be suppressed, thereby suppressing the occurrence of galling. On the other hand, an example of the liquid lubricant is lubricating oil. Examples of the synthetic resin (paint) include epoxy resin, silicon resin, acrylic resin, acrylic silicon resin, chlorinated rubber resin, silicon resin, phenol resin, phthalic acid resin, unsaturated polyester resin, and polyurethane resin.

[0047] Further, at the center position in the longitudinal direction of the unbonded material 20, a projection hole 20a into which the projection 14 of the core material 10 fits is provided.

[0048] The restraining material 30 is formed of 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 restraining material 30 that abuts against the unbonded material 20 is also provided with 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.

[0049] 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 stiffening materials 50 made of steel plates, and the core material 10 is surrounded by the pair of restraint materials 30 and the pair of stiffening materials 50.

[0050] Next, the axial force adjusting means provided on the core material will be described with reference to FIGS.

[0051] The example shown in Figure 4 is a form in which one unit 15 consisting of one through hole 16 and two notches 17 is provided in the narrow width portion 11 of the core material 10, and the one unit 15 shown forms the axial force adjustment means of the core material 10.

[0052] The through-hole 16 is formed by hollowing out the core material 10 in the longitudinal direction thereof with a predetermined width t, for example, by laser processing.

[0053] The width t of the through hole 16 is set to a length between, for example, a length corresponding to the design strain as a lower limit and a buckling length (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 width t of the through hole 16 in this manner, the design strain can be absorbed by the through hole 16, 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, in terms of the planar shape of through hole 16, the contour on the other side (the left side in the illustrated example) where there are no two notches 17 has a first curvature 16a, and the contour on one side (the right side in the illustrated example) where there are two notches 17 has a second curvature 16b that is convex toward first curvature 16a. Here, it is preferable from the viewpoint of manufacturing efficiency that the radii of curvature of first curvature 16a and second curvature 16b are the same, but the radii of curvature of both may be different.

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

[0056] Therefore, by using the through hole 16 and the two notches 17, it is possible to adjust the axial force of the core material 10 and suppress the pressing force in the strong axis direction of the core material 10, while eliminating problems such as the falling off of the spacer S or the occurrence of areas that cannot be stiffened due to 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 16 in the narrow portion 11 of the core material 10, for example by laser processing, and then laser process two notches 17 connecting to the through hole 16, thereby dramatically improving manufacturing efficiency.

[0058] 5A, in the planar shape of through hole 16, the contour 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 contour on the other side of through hole 16. For example, if the contour 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 16, the contour on the other side where there is no notch 17 has a first curvature 16a, and the contour on the one side where there is the 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 FIG. 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 the notch 17 may have a straight line 16c perpendicular to the longitudinal direction of the core material 10.

[0061] In this embodiment, the contour on one side where the incision 17 is located is linear, perpendicular to the longitudinal direction of the core material 10, so that even in this embodiment, 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 compression strain of the core material 10. In addition to this, because the contour on one side is straight line 16c, production efficiency can be improved compared to a form in which the contours on both sides have curvatures.

[0062] As shown in FIG. 4, the two cuts 17 extend to a position midway through the wide portion 12, and ends 17a of the cuts 17 are located at a position midway through the wide portion 12.

[0063] If the ends of the two cuts 17 were located in narrow portion 11, which is a region subject to plastic deformation, the cross-sectional rigidity of core material 10 would change suddenly near the ends of cuts 17, and when an external force during an earthquake is input to core material 10, there is a risk that core material 10 would break near the ends of cuts 17, which could be the point at which the cross-sectional rigidity changes suddenly. In contrast, as in the illustrated example, this problem can be solved by having ends 17a of cuts 17 located midway through wide portion 12, which is a region that does not or is difficult to plastically deform.

[0064] In another embodiment, the ends of the two cuts 17 each have a linear shape that gradually approaches the other cut, which can prevent the cross-sectional stiffness of the core material from suddenly changing at the ends of the two linear cuts. However, in this embodiment, if the distance between the two cuts is small, there may be a case where the margin for making the ends of both cuts linearly approach the other cut cannot be secured, and in such a case, this embodiment cannot be adopted. In contrast, in the illustrated example, the cut 17 is extended to the wide portion 12, so that damage to the core material 10 near the end 17a of the cut 17 can be prevented regardless of the size of the distance between the two cuts 17.

[0065] The position of the end 17a of the notch 17 is preferably set within a range from at least the width transition region 12A included in the wide portion 12 to, for example, just before the bolt hole 12a in the wide portion 12.

[0066] 6 shows an example in which two units 15, each of which has one through hole 16 and two notches 17, are provided in narrow portion 11 of core material 10A. More specifically, in both units 15, the through hole 16 is disposed on the side of protrusion 14 at the center of core material 10A.

[0067] In core material 10A, a virtual slit is formed by a pair of cuts 17 in each of two units 15, and a virtual spacer S formed by core material 10A itself is provided within the virtual slit.

[0068] A gap G is provided between the two through holes 16 forming the left and right units 15, and the two units 15 are not continuous, thereby preventing the two imaginary spacers S from falling out of the core material 10A.

[0069] Further, the two cuts 17 forming the two units 15 each extend to a midpoint of the left and right wide portions 12 , and end portions 17 a of the cuts 17 are located at a midpoint of the wide portions 12 .

[0070] In core material 10A as well, ends 17a of each slit 17 are located midway through wide portion 12, eliminating the risk of damage to the core material during an earthquake when the ends of slits 17 are located in narrow portions 11.

[0071] On the other hand, the example shown in Figure 7 is a form in which one unit 15 is provided in the narrow width portion 11 of the core material 10B, the unit 15 consisting of one through hole 16 and two notches 17 connected to the through hole 16, one on each side of the through hole 16.

[0072] In core material 10B, a virtual slit is formed by a pair of cuts 17 on the left and right of through hole 16, and two virtual spacers S formed by core material 10B itself are provided within the virtual slit.

[0073] As shown by the solid lines in FIG. 8, the through-hole 16 has a rectangular shape in plan view, and both of its left and right contours are defined by straight lines 16d that are perpendicular to the longitudinal direction.

[0074] A through hole 16 that absorbs the design strain of core material 10B is provided in narrow portion 11 of core material 10B, and two left and right notches 17 that communicate with this through hole 16 are provided extending in the longitudinal direction of core material 10, so that a virtual slit for adjusting axial force is formed in core material 10 by the two left and right notches 17, and the area sandwiched between the two left and right notches 17 forms a virtual spacer S inserted into the virtual slit, while being core material 10B itself. And, because the ends of the two left and right notches 17 on the opposite side to through hole 16 are continuous with another core material 10B, the two spacers S sandwiched between the two left and right notches 17 will not fall off from other areas of core material 10B.

[0075] The two left and right cuts 17 forming the unit 15 extend to midway positions of the left and right wide portions 12 , and end portions 17 a of the cuts 17 are located midway positions of the wide portions 12 .

[0076] In core material 10B as well, ends 17a of each slit 17 are located midway through wide portion 12, eliminating the risk of damage to the core material during an earthquake when the ends of slits 17 are located in narrow portion 11.

[0077] Next, with reference to Figs. 9A and 9B, a description will be given of higher-order mode buckling occurring in the weak axis direction of the core material 10.

[0078] The buckling restrained brace 100 is assembled into the building frame by bolting both ends to connecting jigs provided at the corners of the building frame. When the building frame is deformed during an earthquake, an external force such as a horizontal force during the earthquake enters the end of the buckling restrained brace 100 through the connecting jig, and the external force is transmitted as a compressive force N from the end of the core material 10 to the entire area, causing the entire core material 10 to plastically deform, thereby exerting its energy absorption performance during an earthquake. In other words, when a compressive force N acts on the core material 10, a higher-order mode buckling (wave-like deformation) occurs in the weak axis direction throughout the entire core material 10, and the entire core material 10 is buckled as evenly as possible, thereby allowing the entire buckling restrained brace 100 to exert its overall plastic deformation performance.

[0079] 9B, a compressive force N acting on the core material 10 causes buckling in a higher mode, and the peaks of the wavy deformation caused by buckling come into contact with the restraining material 30, applying a compressive force Q to the restraining material 30. Therefore, the local yield strength of the restraining material 30 is set so that the locally acting compressive force Q does not cause localized failure.

[0080] In addition, the present invention is not limited to the configuration shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like of the above-mentioned embodiment. In this regard, the present invention may be modified within the scope of the gist of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0081] 10, 10A, 10B, 10C: Core material 10a: Wide surface 11: Narrow section 12: Wide section 12A: Width transition area 12a: Bolt hole 13: Joint plate 13a: Bolt hole 14: Protrusion 15, 15A: Unit 15B: 1st unit 15C: 2nd unit 16:Through hole 16a: 1st curvature 16b: 2nd curvature 16c,16d: Straight line 17: Cut 17a: End 18A, 18B: Ends (ends of the notches) 19: Reinforcement plate 20: Unbonded material 20a:Protrusion hole 30: Restraint material (square steel pipe) 30a:Protrusion hole 50: Stiffener 100: Buckling restraint brace S: Spacer (virtual spacer) G: Gap N: Axial force (compressive force) Q: Pressing force

Claims

1. A buckling restraint brace having a steel plate-shaped core material and a pair of restraint members made of square steel pipes arranged to face two wide surfaces of the core material, The core material has a narrow portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide portion at an end side in the longitudinal direction, where the width of the wide surface is relatively wide, a 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 are provided on the wide surface of the narrow portion, the through hole and the notches forming an axial force adjustment means for the core material; A buckling restraint brace, characterized in that each of the two cuts extends to one of the wide portions.

2. A buckling restraint brace having a steel plate-shaped core material and a pair of restraint members made of square steel pipes arranged to face two wide surfaces of the core material, The core material has a narrow portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide portion at an end side in the longitudinal direction, where the width of the wide surface is relatively wide, a through hole and two notches communicating with the through hole and extending in the longitudinal direction of the core material on both the left and right sides of the through hole are provided on the wide surface of the narrow portion, the through hole and the notches forming an axial force adjustment means for the core material; A buckling restraint brace, characterized in that both of the two left and right notches extend to the left and right wide portions.

3. Two units each including one through hole and two of the notches are provided with a gap therebetween in the longitudinal direction, The buckling restraint brace according to claim 1, characterized in that in both of the two units, the through hole is positioned toward the center of the narrow portion and the two notches extend to the wide portion.

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, the contour on the other side where the notch is not present has a first curvature, and the contour on the one side where the notch is present has a second curvature that is convex toward the first curvature.

5. 4. The buckling restraint brace according to claim 1, wherein in a planar view of the through hole, the contour on the other side where the notch is not present has a first curvature, and the contour on the one side where the notch is present is a straight line perpendicular to the longitudinal direction.

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

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