Buckling restraint brace

Abstract

To provide a buckling restraint brace that can prevent components from falling off or the occurrence of areas that cannot be stiffened when the core material is deformed, while enjoying 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 a decrease in strength in the strong axis direction.SOLUTION: Provided is a buckling restraint brace 100 having 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 an axial force adjustment means of the core material 10, and both ends 18A of the two notches 17 have a linear shape that gradually approaches the other notch side.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, but by providing slits on the wide surface, the strength of the core material in the strong axis direction decreases, and there is a trade-off in which higher-order mode buckling occurs in the strong axis direction. To suppress this decrease in strength 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 adjust the axial force of the core material while suppressing a decrease in strength in the strong axis direction.

[0007] In a configuration in which a slit is 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 reduction in strength reduction 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 comprising a steel plate-shaped core member, a pair of restraint members made of square steel pipes arranged to face two wide surfaces of the core member, and an unbonded member interposed between the core member and the restraint members, 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 core material, the through hole and the notches forming an axial force adjustment means of the core material; The end portions of the two cuts each have a linear shape that gradually approaches the other cut side.

[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 a decrease in strength of the core material in the strong axis direction, while eliminating problems such as the falling off of the spacer or the creation of areas 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, since both ends of the two notches have a linear shape that gradually approaches the other notch, it is possible to prevent a sudden change in the cross-sectional rigidity of the core material at, for example, the end positions of the two linear notches, and when external forces during an earthquake are input to the core material, it is possible to prevent the core material from being damaged near the ends of the notches, which could be the points of sudden change in cross-sectional rigidity.

[0014] 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 deformable property such as butyl rubber. By interposing this 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 by using the thickness of the unbond material as a clearance when the core material is subjected to a compressive force. 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.

[0015] 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, 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 core material, the through hole and the notches forming an axial force adjustment means of the core material; The end portions of the two cuts each have a linear shape that gradually approaches the other cut side.

[0016] 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 left and right notches form an axial force adjustment means for the core material, so that the area inside the two left and right notches becomes a spacer, and since this spacer is the core material itself and is not inserted into a slit, the through hole and the two left and right notches allow for both adjustment of the axial force of the core material and prevention of a decrease in strength in the strong axis direction of the core material, while eliminating problems such as the falling off of the spacer or the occurrence of areas that cannot be stiffened due to the spacer moving. Furthermore, since both ends of the two notches have a linear shape that gradually approaches the other notch, it is possible to prevent a sudden change in the cross-sectional rigidity of the core material at, for example, the end positions of the two linear notches, and when external forces during an earthquake are input to the core material, it is possible to prevent the core material from being damaged near the ends of the notches, which could be the points of sudden change in cross-sectional rigidity.

[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, a first unit and a second unit are provided on the wide surface of the core material with a gap therebetween in the longitudinal direction of the core material, the first unit and the second unit forming an axial force adjustment means of the core material; the first unit includes 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; the second unit includes a through hole and two notches extending in a longitudinal direction of the core material on both the left and right sides of the through hole, the notches communicating with the through hole, The end portions of the two cuts each have a linear shape that gradually approaches the other cut side.

[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 restraining members made of square steel pipes, a first unit and a second unit which form an axial force adjustment means for the core material are arranged on the wide surfaces of the core material with a gap between them, the first unit has one through hole and two notches which communicate with the through hole and extend in the longitudinal direction of the core material on one side of the through hole, and the second unit has one through hole and two notches which communicate with the through hole and extend in the longitudinal direction of the core material on both the left and right sides of the through hole, respectively.As a result, the area inside the two notches becomes a spacer, and this spacer is the core material itself and is not inserted into a slit, the through holes and multiple notches allow for both adjustment of the axial force of the core material and suppression of a decrease in strength in the strong axis direction of the core material, while eliminating problems such as the occurrence of areas that cannot be stiffened due to the spacer falling off or the spacer moving. Furthermore, since both ends of the two notches have a linear shape that gradually approaches the other notch, it is possible to prevent a sudden change in the cross-sectional rigidity of the core material at, for example, the end positions of the two linear notches, and when external forces during an earthquake are input to the core material, it is possible to prevent the core material from being damaged near the ends of the notches, which could be the points of sudden change in cross-sectional rigidity.

[0019] Another aspect of the buckling restraint brace according to the present invention is The end of the cut is characterized in that it has a curved shape.

[0020] According to the present embodiment, since the linear shape of the end of the notch is curved, the cross-sectional rigidity of the core material at the end of the notch can be gradually changed, and abrupt changes in the cross-sectional rigidity of the core material can be effectively suppressed.

[0021] Another aspect of the buckling restraint brace according to the present invention is The end of the cut is characterized in that it has a tapered shape bent from a straight line in the longitudinal direction.

[0022] According to the present embodiment, since the linear shape of the end of the notch is tapered and bent from a straight line in the longitudinal direction, the cross-sectional rigidity of the core material at the end of the notch can be gradually changed, and sudden changes in the cross-sectional rigidity of the core material can be effectively suppressed.

[0023] Another aspect of the buckling restraint brace according to the present invention is The present invention is characterized in that a plurality of units each consisting of one through hole and two of the notches are provided with gaps in the longitudinal direction.

[0024] According to the present embodiment, multiple units each consisting of one through hole and two notches are provided with gaps 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.

[0025] Another aspect of the buckling restraint brace according to the present invention is The present invention is characterized in that a plurality of units each consisting of one through hole and two notches on each of the left and right sides are provided with gaps in the longitudinal direction.

[0026] According to the present embodiment, multiple units each consisting of one through hole and two notches on each side are provided with gaps 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. This eliminates 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.

[0027] Another aspect of the buckling restraint brace according to the present invention is At least one of the first unit and the second unit is provided in plurality.

[0028] According to this aspect, by providing multiple first units and / or second units, multiple peaks can be effectively restrained during buckling in a higher mode in the strong axis direction of the core material, and the problem of the longitudinal length of the through hole increasing when absorbing design strain by, for example, one through hole, leading to the occurrence of an unstiffened region can be eliminated. Here, "providing multiple first units and / or second units" includes a form having one first unit and multiple second units, a form having multiple first units and one second unit, and a form having multiple first units and multiple second units. Effect of the Invention

[0029] 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 preventing a decrease in strength 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]

[0030] [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 6A] FIG. 2 is an enlarged view of an example of the ends of two incisions in a core material. [Figure 6B]13 is an enlarged view of another example of the ends of two incisions in a core material. FIG. [Figure 7] FIG. 11 is a plan view of another example of the core material. [Figure 8] FIG. 11 is a plan view of another example of the core material. [Figure 9] 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 10] FIG. 13 is a plan view of yet another example of the core material. [Figure 11A] 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 11B] 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

[0031] 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.

[0032] [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 11. Here, Figure 1 is an exploded perspective view of an example of a buckling restrained brace according to an embodiment, Figure 2 is a perspective view of an example of a buckling restrained brace according to an embodiment, and Figure 3 is a longitudinal cross-sectional view of the buckling restrained brace according to an embodiment in a direction perpendicular to the axis. Also, Figure 4 is a plan view of an example of a core material, Figure 5A is an enlarged view of a through hole and a portion of two notches in the core material, showing the state of the core material before and after compression, and Figure 6A is an enlarged view of an example of the ends of the two notches in the core material.

[0033] 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.

[0034] 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.

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

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

[0037] 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.

[0038] 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.

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

[0040] The wide portion 12 and the connecting plate 13 are provided with bolt holes 12a, 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.

[0041] 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.

[0042] 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.

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

[0044] The 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.

[0045] On the sides of the core material 10, both sides (sides corresponding to the short sides of the rectangle) of the pair of restraint materials 30 are connected by welding or the like to a pair of 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.

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

[0047] The example shown in Figure 4 is a 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.

[0048] The through-holes 16 are formed by hollowing out the core material 10 in the longitudinal direction thereof with a predetermined width t1, for example, by laser processing.

[0049] The width t1 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 t1 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.

[0050] 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.

[0051] 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 18A 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.

[0052] Therefore, the through hole 16 and the two notches 17 make it possible to adjust the axial force of the core material 10 and suppress a decrease in strength in the strong axis direction of the core material 10, while eliminating problems such as the falling off of the spacer S or the occurrence of areas that cannot be stiffened due to movement of the spacer S.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] Also, as shown in FIG. 6A, ends 18A of two cuts 17 each have a linear shape that gradually approaches the other cut 17, and in the example shown in FIG. 6A, the linear shape of end 18A is curved.

[0059] In this way, because the ends 18A of the two notches 17 have a linear shape that gradually approaches the other notch 17, a sudden change in the cross-sectional rigidity of the core material 10 at the end positions of the two linear notches 17 can be suppressed, and when external force during an earthquake is input to the core material 10, damage to the core material 10 near the ends of the notches, which could be the points of a sudden change in the cross-sectional rigidity, can be suppressed.

[0060] More specifically, because a virtual spacer S is formed between the two cuts 17, the cross-sectional rigidity in the region of core material 10 where the virtual spacer S exists is reduced by the width of the spacer S compared to the region where the spacer S does not exist. If the ends of the two linear cuts 17 were to stop on a linear line, the cross-sectional rigidity of core material 10 would change abruptly at the line connecting the ends of the two cuts 17.

[0061] In contrast, since the ends of the two notches 17 have a linear shape that gradually approaches the other notch, the cross-sectional rigidity of the core material 10 gradually changes toward the end of the spacer S, thereby suppressing a sudden change in the cross-sectional rigidity of the core material 10 at the end 18A of the notch 17.

[0062] In the example shown in FIG. 6B, the linear shapes of the ends 18B of the two incisions 17 are bent and tapered from a straight line in the longitudinal direction.

[0063] In this way, even when the ends 18B of the two cuts 17 are tapered, the ends 18B of the two cuts 17 have a linear shape that gradually approaches the other cut 17, thereby preventing a sudden change in the cross-sectional rigidity of the core material 10 at the end positions of the two linear cuts 17.

[0064] 7 shows an example in which a plurality of units 15 (two in the illustrated example) each consisting of one through hole 16 and two notches 17 are provided in narrow width portion 11 of core material 10A. More specifically, the left-right positions of through holes 16 in both units 15 relative to the two notches 17 are uniform (in the illustrated example, through hole 16 is located on the left side). Since two units 15 are provided in narrow width portion 11 of core material 10A, each unit 15 is provided on the left and right of central protrusion 14 with through holes 16 located on the left side.

[0065] A virtual slit is formed by a pair of cuts 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. Ends 18A of the two cuts 17 are curved so as to gradually approach the other cut 17 side as described above, but may also have a tapered linear shape.

[0066] 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), and the two units 15 are not continuous.

[0067] Here, two units 15 may be provided with the through holes 16 disposed on the right side. Alternatively, three or more units 15 may be disposed with gaps G between them in the narrow portion 11 of the core material 10A.

[0068] Next, still another example of the core material will be described with reference to Figs.

[0069] The example shown in Figure 8 is a form in which two units 15A, each consisting of one through hole 16A and two notches 17 on either side of the through hole 16A that communicate with the through hole 16A, are provided in the narrow width portion 11 of the core material 10B, and the two units 15A shown form the axial force adjustment means of the core material 10B.

[0070] The through-hole 16A is hollowed out in the longitudinal direction of the core material 10 by, for example, laser processing, to a predetermined width t1.

[0071] A gap G is provided between the two cuts 17 forming the two units 15A (near the center of the core material 10B), and the two units 15A are not continuous. Also, the ends 18A of the two cuts 17 are curved so as to gradually approach the other cut 17 side, as described above.

[0072] Although not shown in the drawings, three or more units 15A may be arranged with gaps G between them in the longitudinal direction of the narrow width portion 11 of the core material 10B.

[0073] As shown by solid lines in FIGS. 8 and 9, the through-hole 16A has a rectangular shape in a plan view, and both left and right contours are defined by straight lines 16d that are perpendicular to the longitudinal direction.

[0074] A through hole 16A 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 16A are provided extending in the longitudinal direction of core material 10B, so that a virtual slit for adjusting axial force is formed in core material 10B 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, although it is core material 10 itself. Furthermore, end portions 18A of the two left and right notches 17 on the opposite side to through hole 16A are continuous with another core material 10B, so 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] Therefore, by using the through hole 16A and the two left and right notches 17, it is possible to adjust the axial force of the core material 10B and suppress a decrease in strength in the strong axis direction of the core material 10B, while eliminating problems such as the falling off of the two spacers S and the creation of areas that cannot be stiffened due to movement of the spacers S.

[0076] Furthermore, since the planar shape of the through hole 16A is rectangular and both left and right contours are straight lines 16d, when the core material 10B is compressed longitudinally in the X2 direction, mutual interference between the left and right straight lines 16d of the through hole 16A is suppressed, and free compression strain of the core material 10B can be ensured.

[0077] On the other hand, the example shown in Figure 10 is a configuration in which two first units 15B and one second unit 15C are provided on the left and right sides of the narrow portion 11 of the core material 10C, respectively, and are arranged between the two first units 15B with a gap G therebetween.

[0078] The first unit 15B has one through hole 16B and two notches 17 that communicate with the through hole 16B on the right side of the through hole 16B. On the other hand, the second unit 15C has one through hole 16C and two notches 17 that communicate with the left and right sides of the through hole 16C. In addition, the ends 18A of the two notches 17 are curved so as to gradually approach the other notch 17 side as described above.

[0079] In the illustrated example, two first units 15B and one second unit 15C are provided on the left and right of the center in the narrow width portion 11 of the core material 10C, and a total of four first units 15B and two second units 15C form the axial force adjustment means of the core material 10C.

[0080] A gap G is provided between adjacent first units 15B and second units 15C or between two adjacent first units 15B, and the first units 15B and second units 15C are not continuous with each other.

[0081] On each of the left and right sides of the narrow width portion 11 of the core material 10C, the two first units 15B have the same left and right positions of the through holes 16B relative to the two cuts 17 (in the illustrated example, the through holes 16B are located on the left side). Here, both of the two first units 15B on each of the left and right sides of the core material 10C may have the two cuts 17 communicating with the through holes 16B on the left side of the through holes 16B (the through holes 16B may be located on the right side).

[0082] The through holes 16B, 16C are both hollowed out by, for example, laser processing, to predetermined widths t2, t3 in the longitudinal direction of the core material 10C.

[0083] The widths t2, t3 of the through holes 16B, 16C are set, for example, to a length between the length corresponding to the design strain as the lower limit and the buckling length (the length between the peaks) when higher-order mode buckling in the strong axis direction occurs in the core material 10C.

[0084] Next, with reference to Figs. 11A and 11B, a description will be given of higher-order mode buckling occurring in the weak axis direction of the core material 10.

[0085] 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.

[0086] 11B, a compressive force N acting on core material 10 causes higher-order mode buckling, and the peaks of the wavy deformation caused by buckling come into contact with restraining material 30, applying a compressive force Q to restraining material 30. For this reason, the local yield strength of restraining material 30 is set so that localized failure does not occur due to the compressive force Q acting locally.

[0087] 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]

[0088] 10, 10A, 10B, 10C: 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 15B: 1st unit 15C: 2nd unit 16:Through hole 16a: 1st curvature 16b: 2nd curvature 16c: straight line 17: Cut 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, 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 core material, the through hole and the notches forming an axial force adjustment means of the core material; A buckling restraint brace, characterized in that the ends of the two cuts each have a linear shape that gradually approaches the other cut side.

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, 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 core material, the through hole and the notches forming an axial force adjustment means of the core material; A buckling restraint brace, characterized in that the ends of the two cuts each have a linear shape that gradually approaches the other cut side.

3. 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, a first unit and a second unit are provided on the wide surface of the core material with a gap therebetween in the longitudinal direction of the core material, the first unit and the second unit forming an axial force adjusting means of the core material; the first unit includes 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; the second unit includes a through hole and two notches extending in a longitudinal direction of the core material on both the left and right sides of the through hole, the notches communicating with the through hole, A buckling restraint brace, characterized in that the ends of the two cuts each have a linear shape that gradually approaches the other cut side.

4. The buckling restraint brace according to claim 1 , wherein the end of the cut has a curved linear shape.

5. The buckling restraint brace according to claim 1 , wherein the end of the cut has a tapered shape bent from a straight line in the longitudinal direction.

6. The buckling restraint brace according to claim 1, characterized in that a plurality of units each consisting of one through hole and two of the notches are provided with gaps in the longitudinal direction.

7. The buckling restraint brace according to claim 2, characterized in that a plurality of units each consisting of one through hole and two notches on each side are provided with gaps in the longitudinal direction.

8. The buckling restraint brace according to claim 3 , characterized in that at least one of the first unit and the second unit is provided in plurality.

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