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; a pair of restraining materials 30 composed of a square steel pipe arranged facing 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 the wide surface 10a of the core material 10, one through hole 16 and two notches 17 are formed extending in the longitudinal direction of the core material 10 in communication with the through hole 16 at the one side of the through hole 16, and the through hole 16 and the notches 17 constitute as the axial force adjustment means of the core material 10.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a buckling restraint brace.

Background Art

[0002] Conventionally, as braces for forming building structures (column-beam structures, roof structures, etc.), buckling restraint braces with buckling prevention measures have been applied. As buckling restraint braces, there are various bracing forms, such as a form in which the periphery of a steel core material is braced only with steel plates, a form in which the periphery of a steel core material is braced with RC (Reinforced Concrete), and a form in which the periphery of a steel core material is covered with steel and mortar.

[0003] Here, Patent Document 1 proposes a buckling restraint brace in which a core material is restrained by a restraint material formed of a pair of square steel pipes, and the buckling restraint brace does not cause local failure in the restraint material receiving a pressing force from the core material. Specifically, it is a buckling restraint brace including a core material having joints for joining with other members at both ends of a plate-shaped portion, and restraint materials arranged to face each surface orthogonal to the weak axis direction of the plate-shaped portion.

[0004] In this buckling restraint brace, slits are provided on the wide surfaces of the core material, and axial force adjustment (or yield strength adjustment) acting on the core material is performed by these slits. Due to these slits, when the core material receives an axial force (compressive force), high-order mode buckling effectively occurs in the weak axis direction of the core material. However, due to the provision of slits on the wide surfaces, there is a trade-off relationship in that the strength in the strong axis direction of the core material decreases and high-order mode buckling occurs in the strong axis direction. To suppress this decrease in strength in the strong axis direction, spacers shorter in length than the slits are inserted into the slits.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] According to the buckling-restrained brace described in Patent Document 1, by providing slits in 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] Incidentally, in a configuration where a slit is provided on the wide surface of the core material and a separately manufactured, relatively short spacer is inserted into it, the length of the slit in the longitudinal direction is made longer than that of the spacer to prevent the predetermined compressive strain in the longitudinal direction of the core material due to the axial force (compressive force) acting during an earthquake from being hindered by the spacer. However, when buckling of higher-order modes occurs while the slit is compressed in the longitudinal direction in this way, there is a risk that the spacer may fall out of the slit due to its own weight. Furthermore, when buckling of higher-order modes occurs in the strong-axis direction of the core material, the spacer may be biased towards one end of the slit, increasing the gap on the other side of the slit and creating a region that is not stiffened by the spacer.

[0008] The present invention has been made in view of the above problems, and aims to provide a buckling-restrained brace that, while enjoying similar effects to the 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 reduction in strength in the strong axis direction, can prevent the member from falling out or the occurrence of a region that cannot be stiffened when the core material deforms. [Means for solving the problem]

[0009] To achieve the above objective, one embodiment of the buckling-restrained brace according to the present invention is: A buckling-restrained brace comprising a steel plate-shaped core material, a pair of restraining members made of rectangular steel pipes arranged opposite to the two wide surfaces of the core material, and an unbonded material interposed between the core material and the restraining members, 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 the notches form a means for adjusting the axial force of the core material.

[0010] According to this embodiment, in a buckling-restrained brace in which two wide surfaces of a steel plate-shaped core are restrained by a pair of restraining members made of square steel pipes, one through-hole and two notches are provided on the wide surface of the core, communicating with the through-hole and extending in the longitudinal direction of the core on one side of the through-hole. The through-hole and the two notches form an axial force adjustment means for the core, so that the area inside the two notches becomes a spacer, and since this spacer is the core itself and not inserted through a slit, the through-hole and the two notches can be used to adjust the axial force of the core and suppress the reduction in strength in the strong axis direction of the core, while eliminating problems such as spacer detachment and the occurrence of areas that cannot be stiffened due to 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 placed, rather than a spacer that is manufactured separately as in the conventional method.

[0012] Furthermore, compared to a manufacturing method that involves processing slits into the wide surface of the core material, separately manufacturing spacers, and inserting the spacers into the slits, this method only requires creating through holes (cutting) into the wide surface of the core material, for example by laser processing, and then processing two notches that connect to the through holes, thus significantly improving manufacturing efficiency.

[0013] Here, 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 acts as a clearance, making it possible to induce higher-order mode buckling within this clearance when the core material is subjected to compressive force.

[0014] Furthermore, other embodiments of the buckling-restrained brace according to the present invention include: The present invention is characterized in that multiple units, each consisting of one through-hole and two notches, are provided with gaps between them in the longitudinal direction.

[0015] According to this embodiment, by providing multiple units consisting of one through-hole and two notches with gaps in the longitudinal direction, multiple peaks during buckling of higher-order modes in the strong axis direction of the core material can be effectively restrained, and the problem of the longitudinal length of the through-hole becoming large when the design strain is absorbed by, for example, one through-hole, which can lead to the occurrence of a region that cannot be stiffened can be resolved.

[0016] Furthermore, other embodiments of the buckling-restrained brace according to the present invention include: The plurality of the aforementioned units are provided in a unified orientation, with the left and right positions of the through-holes relative to the cuts aligned.

[0017] According to this embodiment, since multiple units are provided with the left and right positions of the through holes relative to the cuts in a unified orientation, the strain generated in the core material can be absorbed as evenly as possible by the multiple through holes along the entire longitudinal direction of the core material. For example, there are configurations in which two units are provided along the longitudinal direction of the core material (one unit is provided on each side from the center of the core material), three units are provided, and four units are provided (two units are provided on each side from the center of the core material).

[0018] Furthermore, other embodiments of the buckling-restrained brace according to the present invention include: The plurality of the aforementioned units are provided in a configuration in which the left-right positions of the through-holes with respect to the cuts are reversed left to right.

[0019] According to this aspect, since the plurality of the units are provided in a posture in which the left - right positions of the through - holes with respect to the notch are reversed left - right, for example, at through - holes located at positions separated from each other in the longitudinal direction of the core material, the strain generated in the core material can be absorbed. For example, in a form in which four units are provided along the longitudinal direction of the core material, a form in which two units are provided on the left and right of the center of the core material in a posture in which their respective through - holes are reversed, and a form in which, among the two units on the left and right of the center of the core material, for example, the two units on the right side are both provided in a posture in which the through - holes are arranged on the right side, and the two units on the left side are both provided in a posture in which the through - holes are arranged on the left side, etc. can be cited.

[0020] Another aspect of the buckling restraint brace according to the present invention is Among 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 is continuous without providing the gap.

[0021] According to this aspect, for example, in a form in which two adjacent units are provided in a posture in which the left - right positions of their through - holes are reversed left - right, among 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 is continuous without providing the gap. Thus, the connection between the two units and the core material can be achieved by only one gap.

[0022] Another aspect of the buckling restraint brace according to the present invention is In the plan view shape of the through - hole, the contour on the other side without the notch has a first curvature, and the contour on the one side with the notch has a second curvature convex to the first curvature side.

[0023] According to this aspect, in the plan view shape of the through hole, since the contour on the other side without a notch has a curvature (first curvature), it is possible to suppress the generation of a stress concentration region around the contour on the other side of the through hole. For example, when the contour on the other side without a notch has a shape having two corner portions of a rectangle, the periphery of these corner portions becomes a stress concentration region, and local damage is feared.

[0024] Furthermore, in the plan view shape of the through hole, the contour on the other side without a notch has a first curvature, and the contour on the one side with a notch has a second curvature convex toward the first curvature side, that is, the contours of the left and right end faces (both end faces in the longitudinal direction) of the through hole both have a curvature convex in the same direction. Thus, when the core material is compressed in the longitudinal direction, the contour on the 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 the free (designed) compressive 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 with the same curvature radius.

[0025] Also, another aspect of the buckling restraint brace according to the present invention is In the plan view shape of the through hole, the contour on the other side without the notch has a first curvature, and the contour on the one side with the notch has a linear shape orthogonal to the longitudinal direction.

[0026] According to this aspect, since the contour on the other side without a notch has a first curvature, as described above, it is possible to suppress the generation of a stress concentration region around the contour on the other side of the through hole. Also, since the contour on the one side with a notch has a linear shape orthogonal to the longitudinal direction, in this form as well, when the core material is compressed in the longitudinal direction, the mutual interference between the contour on the other side (first curvature) and the contour on the one side (a straight line orthogonal to the longitudinal direction) of the through hole is suppressed, and in addition to being able to ensure the free (designed) compressive strain of the core material, since the contour on the one side is a straight line, the manufacturing efficiency can be improved compared to a form in which both the contours on the one side and the other side have curvatures.

[0027] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, A pair of connecting plates are fixed to both ends of the core material, perpendicular to the wide surface and joined to other members. A reinforcing plate is fixed to the pair of joining plates, and the end of the restraining member is housed in the space formed by the wide surface, the pair of joining plates, and the reinforcing plate. On the side of the core material, a pair of stiffening members connect both sides of the pair of restraining members. The core material is characterized by being surrounded by the pair of restraining members and the pair of stiffening members.

[0028] In this embodiment, 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 member is housed in the space formed by the wide surface, the pair of connecting plates, and the reinforcing plate, thereby creating 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 plane from corners of building frames, etc. Furthermore, if the end of the core material is a web, the pair of connecting plates perpendicular to this web become a pair of flanges.

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

[0030] Furthermore, the buckling-restrained brace according to the present invention may have an interposition plate between the unbonded material and the restraining material. In this configuration, the interposition of an interposition plate, for example made of steel, between the unbonded material and the restraining material allows the compressive force due to buckling of higher-order modes in the weak axis direction of the core material to act directly on the restraining material, effectively suppressing local failure of the restraining material. [Effects of the Invention]

[0031] As can be understood from the above explanation, the buckling-restrained brace of the present invention provides similar effects to the 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 reduction in strength in the strong axis direction, while preventing the member from falling out or the occurrence of areas that cannot be stiffened when the core material deforms. [Brief explanation of the drawing]

[0032] [Figure 1] This is an exploded perspective view of an example of a buckling-restrained brace according to an embodiment. [Figure 2] This is a perspective view of an example of a buckling-restrained brace according to an embodiment. [Figure 3] This is a longitudinal cross-sectional view of the buckling-restrained brace according to the embodiment, in the direction perpendicular to the axis. [Figure 4] A plan view of an example of a core material. [Figure 5A] This is a magnified view of a portion of the through-hole and two cuts in the core material, and is a plan view showing the state of the core material before and after compression. [Figure 5B] This is a plan view showing another example of a through-hole in the core material and a magnified view of part of two cuts, illustrating the state of the core material before and after compression. [Figure 6] This is a plan view of another example of the core material. [Figure 7] This is a plan view of yet another example of the core material. [Figure 8] This is a plan view of yet another example of the core material. [Figure 9A] This is a schematic longitudinal cross-sectional view of a buckling-restrained brace in the direction perpendicular to the axis, illustrating the state in which the compressive force during higher-order mode buckling acts from the core material to the restraining material. [Figure 9B] This is a schematic axial longitudinal section diagram of a buckling-restrained brace, illustrating the state in which compressive forces during higher-order mode buckling are acting from the core material to the restraining material. [Modes for carrying out the invention]

[0033] The buckling-restrained brace according to the embodiment will be described below with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0034] [Buckling-restrained brace according to an embodiment] An example of a buckling-restrained brace according to the 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 the embodiment, Figure 2 is a perspective view of an example of a buckling-restrained brace according to the embodiment, and Figure 3 is a longitudinal cross-sectional view of the buckling-restrained brace according to the embodiment in the direction perpendicular to the axis. Furthermore, Figure 4 is a plan view of an example of a core material, and Figure 5A is an enlarged view of a part of the through hole and two cuts in the core material, showing the state of the core material before and after compression.

[0035] The buckling-restrained brace 100 comprises a core material 10, a pair of restraining members 30 arranged to face the two wide surfaces 10a of the core material 10, and an unbonded material 20 interposed between the core material 10 and the restraining members 30. In addition to the illustrated example, an insert plate made of steel plate may be interposed between the unbonded material 20 and the restraining members 30.

[0036] The core material 10 is preferably made of steel with a low yield point, such as SN material (rolled steel for building structures) or LYP material (ultra-low yield point steel). By applying a core material 10 made of these materials, the seismic energy absorption performance due to yielding of the core material 10 is improved.

[0037] The core material 10 is formed from an elongated steel plate, and has a narrow section 11 at the center of its longitudinal direction where the width of the wide surface 10a is relatively narrow, and a wide section 12 at the end of its longitudinal direction where the width of the wide surface 10a is relatively wide.

[0038] The core material 10 has a narrow section 11 on its longitudinal central side and a wide section 12 on its longitudinal end side. This makes the narrow section 11 on the central side a region that is easily plasticized, and furthermore, the plasticization region can be limited to the narrow section 11 on the central side. Here, the boundary region between the narrow section 11 and the wide section 12 of the core material 10 has a shape in which the width gradually widens in a curved manner from the narrow section 11 to the wide section 12, preventing the occurrence of localized stress concentration areas due to abrupt changes in width.

[0039] At the center of the narrow section 11 of the core material 10, cylindrical steel projections 14 protrude from the two wide surfaces 10a of the narrow section 11. The projections 14 are joined to the wide surfaces 10a of the narrow section 11 by welding or the like.

[0040] Furthermore, the narrow portion 11 of the core material 10 is provided with a 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 of the through hole 16 (the right side in the illustrated example). This unit 15 will be described in detail below.

[0041] A pair of steel plates, each consisting of a connecting plate 13, are joined to the wide sections 12 at both ends of the core material by welding or other means, perpendicular to the wide surface 10a and connected to other members.

[0042] The wide section 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 members) such as brackets and gusset plates that protrude into the structural plane from corners of a building frame (not shown), and are bolted together.

[0043] A reinforcing plate 18 made of steel is joined to a pair of connecting plates 13 by welding or the like, and the end of the restraint member 30 is housed in the space formed by the wide portion 12 of the core material 10, the pair of connecting plates 13, and the reinforcing plate 18. The reinforcing plate 18 suppresses the opening of the end of the core material 10 of the restraint member 30 in the weak axis direction, thereby suppressing a decrease in strength and damage to the end of the buckling restraint brace 100.

[0044] The unbonded material 20 is interposed between the narrow portion 11 of the core material 10 and the restraining material 30, and the thickness of the unbonded material 20 provides a clearance so that when the building frame deforms, a compressive force acts on the core material 10, causing buckling (wavy deformation) of a higher-order mode in the out-of-plane direction (weak axis direction) in the narrow portion 11.

[0045] For the unbonded material 20, an elastic material such as butyl rubber is used. In addition, a projection hole 20a is provided at the center of the longitudinal direction of the unbonded material 20, into which the projection 14 of the core material 10 fits.

[0046] The restraining member 30 is formed from a rectangular steel pipe with a rectangular cross-section, and the side corresponding to the longer side of the rectangle is in contact with the unbonded material 20. The side of the restraining member 30 that is in contact with the unbonded material 20 is also provided with a projection hole 30a into which the projection 14 of the core material 10 fits. In the illustrated example, each corner of the rectangular steel pipe 30 is not a right angle but forms a curved surface (R section), but each corner may be a right angle.

[0047] On the side of the core material 10, a pair of stiffeners 50 made of steel plates connect both sides (the sides corresponding to the shorter sides of the rectangle) of a pair of restraining members 30 by welding or the like, and the core material 10 is surrounded by the pair of restraining members 30 and the pair of stiffeners 50.

[0048] Next, with reference to Figures 4 to 8, the axial force adjustment means provided in the core material will be described.

[0049] In the example shown in Figure 4, a unit 15 consisting of one through hole 16 and two notches 17 is provided in the narrow portion 11 of the core material 10, and the illustrated unit 15 forms the axial force adjustment means of the core material 10.

[0050] The through-hole 16 is cut out in the longitudinal direction of the core material 10 with a predetermined width t, for example, by laser processing.

[0051] The width t of the through-hole 16 is set to a length between, for example, the length corresponding to the design strain as the lower limit and the buckling length (length between peaks) when buckling of a higher-order mode in the strong axis direction occurs in the core material 10 as the upper limit. By setting the width t of the through-hole 16 in this way, the design strain can be absorbed by the through-hole 16, and the stiffening effect during buckling of a higher-order mode in the strong axis direction of the core material 10 can be ensured.

[0052] As shown by the solid lines in Figures 4 and 5A, the plan view shape of the through hole 16 is such that the contour on the side without the two notches 17 (left side in the illustrated example) has a first curvature 16a, and the contour on the side with the two notches 17 (right side in the illustrated example) has a second curvature 16b that is convex toward the first curvature 16a side. Here, it is preferable from the viewpoint of manufacturing efficiency that the radii of curvature of both the first curvature 16a and the second curvature 16b are the same, but the radii of curvature of both may be different.

[0053] In the narrow portion 11 of the core material 10, a through hole 16 is provided to absorb the design strain of the core material 10. Two notches 17 are provided that communicate with this through hole 16 and extend 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 axial force adjustment, and the area sandwiched between the two notches 17 forms a virtual spacer S inserted into the virtual slit, even though it is the core material 10 itself. Furthermore, since the ends of the two notches 17 opposite to the through hole 16 (the right end in the illustrated example) are continuous with the rest of the core material 10, the spacer S sandwiched between the two notches 17 will not fall out from other areas of the core material 10.

[0054] Therefore, the through hole 16 and the two notches 17 allow for both adjustment of the axial force of the core material 10 and suppression of strength reduction in the strong axis direction of the core material 10, while eliminating problems such as the spacer S falling off or the occurrence of areas where stiffening is not possible due to the movement of the spacer S.

[0055] Furthermore, compared to the conventional manufacturing method in which a slit is processed into the narrow portion of the core material, a spacer is manufactured separately, and the spacer is inserted into the slit, the illustrated example only requires, for example, laser processing to create a through hole 16 in the narrow portion 11 of the core material 10, and then laser processing two notches 17 that communicate with the through hole 16, thus significantly improving manufacturing efficiency.

[0056] Furthermore, as shown in Figure 5A, in the plan view shape of the through hole 16, the contour on the other side without the notch 17 (the left side in the illustrated example) has a first curvature 16a, which suppresses the occurrence of stress concentration regions around the contour on the other side of the through hole 16. For example, if the contour on the other side without the notch 17 has a rectangular shape with two corners, the area around these corners will become a stress concentration region, raising concerns about localized damage.

[0057] Furthermore, in the plan view shape of the through hole 16, the contour on the other side without the notch 17 has a first curvature 16a, and the contour on the one side with the notch 17 (the right side in the illustrated example) has a second curvature 16b that is convex toward the first curvature 16a. As a result, when the core material 10 is compressed in the longitudinal direction 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 compressive strain of the core material 10.

[0058] Here, as shown in Figure 5B, in the plan view shape of the through hole 16A forming the unit 15A, the contour on the other side without the notch 17 may have a first curvature 16a, and the contour on the one side with the notch 17 may have a straight line 16c perpendicular to the longitudinal direction of the core material 10.

[0059] In this configuration, the contour on one side with the notch 17 is a straight line perpendicular to the longitudinal direction of the core material 10. Therefore, even in this configuration, when the core material 10 is compressed in the longitudinal direction X1, mutual interference between the first curvature 16a of the through hole 16A and the straight line 16c on one side is suppressed, and the free compressive strain of the core material 10 can be guaranteed. In addition, because the contour on one side is a straight line 16c, manufacturing efficiency can be improved compared to a configuration in which both the contours on one side and the other side have curvature.

[0060] The example shown in Figure 6 is a configuration in which multiple units 15, each consisting of one through-hole 16 and two notches 17, are provided in the narrow section 11 of the core material 10A (two units in the illustrated example). More specifically, in both units 15, the left-right position of the through-hole 16 relative to the two notches 17 is consistent (in the illustrated example, the through-hole 16 is positioned on the left side). Since two units 15 are provided in the narrow section 11 of the core material 10A, each unit 15 is provided on either side of the central projection 14, with the through-hole 16 positioned on the left side.

[0061] A virtual slit is formed by a pair of notches 17 in each of the two units 15, and a virtual spacer S formed by the core material 10 itself is provided within the virtual slit.

[0062] A gap G is provided between the two notches 17 that form the left unit 15 and the through hole 16 that forms the right unit 15 (near the center of the core material 10A), so the two units 15 are not continuous.

[0063] Here, the two units 15 may be arranged in a configuration where each through-hole 16 is positioned on the right side. Alternatively, in the narrow portion 11 of the core material 10A, three or more units 15 may be arranged with gaps G between them.

[0064] In the example shown in Figure 7, in the narrow section 11 of the core material 10B, the left-right positions of the through holes 16 relative to the two notches 17 are reversed in both units 15 (in the illustrated example, the through hole 16 of the left unit 15 is located on the left side, and the through hole 16 of the right unit 15 is located on the right side). In the core material 10B as well, a virtual slit is formed by the pair of notches 17 of each of the two units 15, and a virtual spacer S formed by the core material 10B itself is provided within the virtual slit.

[0065] A gap G is provided between the two notches 17 that form the left and right units 15 (near the center of the core material 10), and the two units 15 are not continuous.

[0066] Here, although not shown in the diagram, the core material 10B may be provided with four units 15, with two units 15 having the through-hole 16 positioned on the left side to the left of the center of the core material 10B, and two units 15 having the through-hole 16 positioned on the right side to the right of the center. Alternatively, there may be a total of six or eight units 15 (each with three and four units 15 on the left and four on the right sides, respectively, where the positions of the through-holes 16 are reversed left and right).

[0067] The example shown in Figure 8 is a configuration in which one of the two gaps G in the core material 10B shown in Figure 7 is eliminated, and the corresponding notches 17 of both units 15 are continuous.

[0068] In this configuration as well, the presence of a gap G between the corresponding notches 17 of both units 15 forms a virtual spacer S between the pair of notches 17 on the left and right, and these are integrated with the area outside the notches 17 in the core material 10C via the gap G, thereby preventing the virtual spacer S from falling out of the core material 10C.

[0069] Here, in the core materials 10A, 10B, and 10C shown in Figures 6 to 8, the through-hole 16A shown in Figure 5B may be used instead of the through-hole 16 of each unit 15.

[0070] As explained above, the buckling-restrained brace 100, by having core members 10, 10A, 10B, and 10C, enjoys the same effects as the conventional structure in which spacers are inserted into slits in the core members, such as adjusting the axial force of the core members and suppressing the reduction in strength in the strong axis direction, while preventing problems such as the spacers falling out or the occurrence of areas in the slits that cannot be stiffened when the core members 10, 10A, 10B, and 10C deform.

[0071] Next, with reference to Figure 9, we will explain the buckling of higher-order modes occurring in the weak axis direction of the core material 10.

[0072] The buckling-restrained brace 100 is incorporated into the building frame by bolting its ends to connecting fixtures provided at corners or other locations within 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 via the connecting fixtures. These external forces are transmitted as a compressive force N from the ends of the core material 10 to its entire surface, causing the entire core material 10 to undergo plastic deformation, thereby exhibiting its energy absorption performance during earthquakes. In other words, when a compressive force N acts on the core material 10, higher-order mode buckling (wave-like deformation) occurs in the weak axis direction throughout the entire core material 10, causing the entire core material 10 to buckle as uniformly as possible, thereby enabling the buckling-restrained brace 100 to exhibit its overall plastic deformation performance.

[0073] As shown in Figure 9B, the compressive force N acting on the core material 10 causes buckling of higher-order modes, and the peaks of the wave-like deformation due to buckling come into contact with the restraining member 30, applying a pressing force Q to the restraining member 30. Therefore, the local yield strength of the restraining member 30 is set so that local failure does not occur in response to the locally acting pressing force Q.

[0074] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0075] 10: Core material 10a: Wide surface 11: Narrow section 12: Wide section 12a: Bolt hole 13: Joint plate 13a: Bolt hole 14: Protrusion 15,15A: Unit 16: Through hole 16a: 1st curvature 16b: 2nd curvature 16c: straight line 17: Cut 18: Reinforcement plate 20: Unbonded material 20a:Protrusion hole 30: Retaining 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 comprising a steel plate-shaped core material, a pair of restraining members made of rectangular steel pipes arranged opposite to the two wide surfaces of the core material, and an unbonded material interposed between the core material and the restraining members, 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 the notches form an axial force adjustment means for the core material. Multiple units, each consisting of one through-hole and two notches, are provided with gaps between them in the longitudinal direction. Multiple of the aforementioned units are provided in a configuration in which the left-right position of the through-hole relative to the cut is reversed left to right, A buckling-restrained brace characterized in that, of the two notches extending from the left and right, there is a gap between one pair of corresponding notches, and the other pair of corresponding notches is continuous without the gap.

2. The buckling-restrained brace according to claim 1, characterized in that, in the plan view shape of the through hole, the contour on the other side without the notch has a first curvature, and the contour on the side with the notch has a second curvature that is convex toward the first curvature side.

3. The buckling-restrained brace according to claim 1, characterized in that, in the plan view shape of the through hole, the contour on the other side without the notch has a first curvature, and the contour on the one side with the notch is a straight line perpendicular to the longitudinal direction.

4. A pair of connecting plates are fixed to both ends of the core material, perpendicular to the wide surface and joined to other members. A reinforcing plate is fixed to the pair of joining plates, and the end of the restraining member is housed in the space formed by the wide surface, the pair of joining plates, and the reinforcing plate. On the side of the core material, a pair of stiffening members connect both sides of the pair of restraining members. The buckling-restrained brace according to any one of claims 1 to 3, characterized in that the core material is surrounded by the pair of restraining members and the pair of stiffening members.

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