JP7852201B2 - Buckling-restrained brace - Google Patents

Description

This invention relates to a buckling-restrained brace.

Conventionally, buckling-restrained braces, which incorporate buckling prevention measures, have been used as braces to form building structures (column and beam frames, roof frames, etc.). Various bracing configurations exist for buckling-restrained braces, including those with a steel core reinforced only with steel plates, those reinforced with reinforced concrete (RC), and those covered with steel and mortar.

Here, Patent Document 1 proposes a buckling-restrained brace in which the core material is restrained by a restraining member formed from a pair of square steel pipes, and which prevents localized failure of the restraining member that receives compressive force from the core material. Specifically, it is a buckling-restrained brace comprising a core material having joints at both ends of a plate-like portion for joining with other members, and restraining members arranged opposite each surface perpendicular to the weak axis direction of the plate-like portion.

In this buckling-restrained brace, slits are provided on the wide surface of the core material, allowing for adjustment of the axial force (or load-bearing capacity) acting on the core material. These slits effectively induce higher-order mode buckling in the weak-axis direction of the core material when subjected to axial force (compressive force). However, the presence of slits on the wide surface reduces the strength of the core material in the strong-axis direction, creating a trade-off where higher-order mode buckling occurs in the strong-axis direction. To mitigate this reduction in strength in the strong-axis direction, spacers shorter than the slits are inserted into the slits.

Patent No. 6445862

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.

Incidentally, in a configuration where a slit is provided in 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. This prevents 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 become 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.

This invention has been made in view of the above problems, and aims to provide a buckling-restrained brace that, while enjoying similar effects to conventional structures in which spacers are inserted into slits 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 areas where stiffening is not possible when the core material deforms.

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.

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, the wide surfaces of the core are provided with one through-hole and two notches that communicate with the through-hole and extend 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 acts as a spacer. Since this spacer is the core itself and not inserted through a slit, the through-hole and the two notches allow for both axial force adjustment of the core and suppression of strength reduction in the strong axis direction of the core, while eliminating problems such as spacer detachment and the occurrence of areas where stiffening is not possible due to spacer movement.

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 conventional methods.

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 significantly improves manufacturing efficiency because it 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.

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, allowing higher-order mode buckling to occur within this clearance when the core material is subjected to compressive force.

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.

According to this embodiment, by providing multiple units consisting of one through-hole and two notches spaced apart in the longitudinal direction, multiple buckling points during higher-order modes in the strong-axis direction of the core material can be effectively restrained. This eliminates the problem of the longitudinal length of the through-hole becoming large when absorbing design strain, for example, through a single through-hole, which can lead to the occurrence of a region where stiffening is not possible.

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.

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

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.

According to this embodiment, by arranging the multiple units in a position where the left-right positions of the through-holes relative to the cuts are reversed, strain generated in the core material can be absorbed, for example, in through-holes located at mutually separated positions in the longitudinal direction of the core material. For example, in a configuration where four units are provided along the longitudinal direction of the core material, examples include a configuration where two units are provided on the left and right sides of the core material's center, with their through-holes reversed, and a configuration where, for example, the two units on the right side of the core material's center both have their through-holes positioned on the right, and the two units on the left side both have their through-holes positioned on the left.

Furthermore, other embodiments of the buckling-restrained brace according to the present invention include:
The invention is 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.

According to this embodiment, for example, in a configuration where two adjacent units are provided with their through-holes positioned in a left-right inverted orientation, a gap exists between one pair of corresponding notches from each of the two notches extending from the left and right, while the other pair of corresponding notches continues without a gap. This allows the two units to be connected to the core material through only one gap.

Furthermore, other embodiments of the buckling-restrained brace according to the present invention include:
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.

According to this embodiment, in the plan view shape of the through-hole, the contour on the other side without a cut has curvature (first curvature), thereby suppressing the occurrence of stress concentration regions around the contour on the other side of the through-hole. For example, if the contour on the other side without a cut has a rectangular shape with two corners, the area around these corners becomes a stress concentration region, raising concerns about localized damage.

Furthermore, in the plan view of the through-hole, the contour on the 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. That is, both the left and right end faces of the through-hole (both longitudinal ends) have curvatures that are convex in the same direction. Therefore, 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), suppressing mutual interference between the two and ensuring the core material's free (design) compressive strain. Here, from the viewpoint of manufacturing efficiency, it is preferable that the first and second curvatures are processed with the same radius of curvature.

Furthermore, other embodiments of the buckling-restrained brace according to the present invention include:
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 is a straight line perpendicular to the longitudinal direction.

According to this embodiment, since the contour on the other side without the notch has a first curvature, the occurrence of a stress concentration region around the contour on the other side of the through-hole can be suppressed, as described above. Furthermore, since the contour on the one side with the notch is a straight line perpendicular to the longitudinal direction, even in this configuration, when the core material is compressed in the longitudinal direction, mutual interference between the contour on the other side of the through-hole (first curvature) and the contour on the one side (straight line perpendicular to the longitudinal direction) is suppressed, ensuring the free (design) compressive strain of the core material. In addition, because the contour on one side is a straight line, manufacturing efficiency can be improved compared to configurations where both the one and the other contours have curvature.

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 connects 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.

According to this embodiment, a pair of connecting plates perpendicular to the wide surface are fixed at both ends of the core material, and reinforcing plates are fixed to the pair of connecting plates. The ends of the restraining member are housed in the space formed by the wide surface, the pair of connecting plates, and the reinforcing plates, 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 plane from corners of building frames. Furthermore, if the ends of the core material are webs, the pair of connecting plates perpendicular to this web become a pair of flanges.

Furthermore, by connecting a pair of restraining members to both sides of the core material on its lateral side 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.

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

As can be understood from the above explanation, the buckling-restrained brace of the present invention, while enjoying the same effects as the conventional structure in which spacers are inserted into slits 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 areas that cannot be stiffened when the core material deforms.

This is an exploded perspective view of an example of a buckling-restrained brace according to an embodiment. This is a perspective view of an example of a buckling-restrained brace according to an embodiment. This is a longitudinal cross-sectional view of the buckling-restrained brace according to the embodiment, in the direction perpendicular to the axis. A plan view of an example of a core material. 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. 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. This is a plan view of another example of the core material. This is a plan view of yet another example of the core material. This is a plan view of yet another example of the core material. 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. 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.

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

[Buckling-restrained brace according to this 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.

The buckling-restrained brace 100 comprises a core material 10, a pair of restraint 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 restraint members 30. In addition to the illustrated example, an interposition plate made of steel sheet may be interposed between the unbonded material 20 and the restraint members 30.

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

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.

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 allows the narrow section 11 on the central side to be 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 where 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.

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 other means.

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.

At both ends of the core material, the wide sections 12 are joined by welding or other means to a pair of steel plates 13 that are perpendicular to the wide surface 10a and joined to other members.

The wide section 12 and the connecting plate 13 are provided with bolt holes 12a and 13a, respectively. These 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 the building frame (not shown), and are bolted together.

A reinforcing plate 18 made of steel is joined to a pair of connecting plates 13 by welding or other means. 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 restraint member 30 of the core material 10 in the weak axis direction, thereby suppressing a decrease in strength and damage to the end of the buckling-restrained brace 100.

The unbonded material 20 is interposed between the narrow portion 11 of the core material 10 and the restraining material 30. The thickness of the unbonded material 20 provides a clearance, causing a compressive force to act on the core material 10 during deformation of the building frame, resulting in buckling (wavy deformation) of a higher-order mode in the out-of-plane direction (weak axis direction) of the narrow portion 11.

As the unbonded material 20, an elastic material such as butyl rubber is used. Furthermore, 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.

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 abuts against the unbonded material 20. The side of the restraining member 30 that abuts against the unbonded material 20 is also provided with a projection hole 30a into which the projection 14 of the core material 10 fits. Note that in the illustrated example, the corners of the rectangular steel pipe 30 are not right angles but curved (R-shaped), however, the corners may also be right angles.

On the side of the core material 10, a pair of stiffening members 50, made of steel plates, are connected to both sides (corresponding to the shorter sides of the rectangle) of a pair of restraining members 30 by welding or other means. The core material 10 is surrounded by the pair of restraining members 30 and the pair of stiffening members 50.

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

The example shown in Figure 4 is a configuration in which a single unit 15, consisting of one through-hole 16 and two notches 17, is provided in the narrow portion 11 of the core material 10. This single unit 15 forms the axial force adjustment means for the core material 10.

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.

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 occurs in the core material 10 in the strong axis direction due to higher-order modes, with the upper limit being the length between these two values. 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 the core material 10 in the strong axis direction due to higher-order modes can be ensured.

As shown by the solid lines in Figures 4 and 5A, the plan view shape of the through-hole 16 has a first curvature 16a on the side without the two notches 17 (left side in the illustrated example), and a second curvature 16b convex toward the first curvature 16a on the side with the two notches 17 (right side in the illustrated example). While it is preferable from the viewpoint of manufacturing efficiency for the radii of curvature of both the first curvature 16a and the second curvature 16b to be the same, their radii of curvature may be different.

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, extending in the longitudinal direction of the core material 10 and communicating with this through-hole 16. As a result, the two notches 17 form a virtual slit in the core material 10 for axial force adjustment. The region sandwiched between the two notches 17, while still being part of the core material 10, forms a virtual spacer S inserted into the virtual slit. Furthermore, since the ends of the two notches 17 opposite the through-hole 16 (the right-hand ends in the illustrated example) are continuous with other parts of the core material 10, the spacer S sandwiched between the two notches 17 will not fall out of other areas of the core material 10.

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 simultaneously resolving issues such as the detachment of the spacer S and the occurrence of areas where stiffening is not possible due to the movement of the spacer S.

Furthermore, compared to the conventional manufacturing method, which involves processing a slit in the narrow portion of the core material, separately manufacturing a spacer, and then inserting the spacer into the slit, the illustrated example significantly improves manufacturing efficiency because, for example, a through-hole 16 is created in the narrow portion 11 of the core material 10 by laser processing, and two notches 17 communicating with the through-hole 16 are then laser-processed.

Furthermore, as shown in Figure 5A, in the plan view 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 areas around these corners will become stress concentration regions, raising concerns about localized damage.

Furthermore, in the plan view 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 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. Therefore, 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.

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

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, ensuring free compressive strain of the core material 10. Furthermore, because the contour on one side is a straight line 16c, manufacturing efficiency can be improved compared to configurations where both the contours on one and the other side have curvature.

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.

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.

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

Here, the two units 15 may be arranged with their through holes 16 positioned to the right. Alternatively, three or more units 15 may be arranged in the narrow section 11 of the core material 10A with gaps G between them.

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 positioned on the left side, and the through hole 16 of the right unit 15 is positioned on the right side). In the core material 10B as well, a virtual slit is formed by the pair of notches 17 in each of the two units 15, and a virtual spacer S formed by the core material 10B itself is provided within this virtual slit.

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.

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

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.

In this configuration, the presence of a single 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. This spacer S is integrated with the outer region of the notches 17 in the core material 10C via the gap G, thus preventing the virtual spacer S from falling out of the core material 10C.

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.

As explained above, the buckling-restrained brace 100, by incorporating core members 10, 10A, 10B, and 10C, enjoys similar effects to conventional structures where 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. However, it prevents problems such as the spacers falling out or the occurrence of un-stiffened regions in the slits during deformation of the core members 10, 10A, 10B, and 10C.

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

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 enter the ends of the buckling-restrained brace 100 via the connecting fixtures. This external force is transmitted as a compressive force N from the ends of the core material 10 to its entire surface, causing plastic deformation of the entire core material 10, 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. By causing the entire core material 10 to buckle as uniformly as possible, the overall plastic deformation performance of the buckling-restrained brace 100 can be achieved.

As shown in Figure 9B, the compressive force N acting on the core material 10 causes buckling in higher-order modes. The peaks of the wavy 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 under the locally acting pressing force Q.

Furthermore, other embodiments may exist 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 are possible without departing from the spirit of the present invention, and can be appropriately determined according to the application.

10: Core material 10a: Wide surface 11: Narrow section 12: Wide section 12a: Bolt hole 13: Joint plate 13a: Bolt hole 14: Projection 15, 15A: Unit 16: Through hole 16a: First curvature 16b: Second curvature 16c: Straight line 17: Notch 18: Reinforcement plate 20: Unbonded material 20a: Projection hole 30: Retaining material (square steel pipe)
30a: Projection hole 50: Stiffener 100: Buckling-restrained brace S: Spacer (virtual spacer)
G: Gap N: Axial force (compressive force)
Q: Pressure force

Claims (4)

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. 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. 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. 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 connects 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.