JP2024083923A - Buckling restraint brace - Google Patents

Abstract

To provide a buckling restraining brace capable of suppressing the rupture of a core material due to the concentration of stress on a dislocation preventing projection.SOLUTION: A buckling restraining brace comprises a core material 10, a restraining member 30 covering the outer periphery of the core material 10, and a filler 31 filled between the core material 10 and the restraining member 30 and covering the core material 10, a displacement preventing projection 40 for preventing displacement of the core material 10 is provided in the central part of the core material 10, and the displacement preventing projection 40 is covered with a filler 31, the width of the displacement prevention projection 40 increases from the tip of the displacement prevention projection 40 toward the root of the displacement prevention projection 40.SELECTED DRAWING: Figure 1

Description

The present invention relates to a buckling restraint brace.

Buckling-restrained braces have traditionally been used as reinforcing materials for structures. In buckling-restrained braces, the core material that receives axial force is restrained from the outer periphery by restraining members and fillers, etc., allowing the core material to undergo plastic deformation while being prevented from buckling or deforming in any direction other than the longitudinal direction. The use of buckling-restrained braces improves the earthquake resistance and vibration control performance of structures.

In the buckling restraint brace of Patent Document 1, to prevent misalignment between the core material and the restraint member, a misalignment prevention protrusion is provided in the center of the core material, and a recess that engages with the misalignment prevention protrusion is provided in the center of the restraint member.

JP 2001-214541 A

In the structure of Patent Document 1, the anti-slip projections are provided perpendicular to the core material. Therefore, when a longitudinal tensile force is applied to the core material, stress tends to concentrate at the base of the anti-slip projections. When stress concentrates at the base of the anti-slip projections, cracks may occur starting from the base, causing the core material to break.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a buckling restraint brace that can prevent breakage of the core material due to stress concentration on the anti-slip protrusions.

<1> A buckling restraint brace according to one aspect of the present invention is a buckling restraint brace that is attached to a structure and includes a core material, a restraining member that covers the outer periphery of the core material, and a filler that is filled between the core material and the restraining member and covers the core material. The central portion of the core material is provided with a slippage prevention protrusion for preventing slippage of the core material, the slippage prevention protrusion is covered with the filler, and the width of the slippage prevention protrusion increases from the tip of the slippage prevention protrusion toward the base of the slippage prevention protrusion.

By increasing the width of the anti-slip protrusion from its tip towards its base, the base, where stress is likely to concentrate, can be made relatively thicker, dispersing stress at the base and making cracks less likely to occur. This prevents cracks from occurring at the base and inhibits breakage of the core material caused by such cracks, improving the fatigue properties of the core material against repeated earthquakes.

<2> In the buckling restraint brace according to <1> above, the tip may be configured to include a straight portion parallel to the longitudinal direction of the core material.

The anti-slip projections are formed by cutting them out of a steel plate. The inclusion of a straight portion at the tip improves the efficiency of cutting the plate from the steel material, thereby improving material yield.

<3> In the buckling restraint brace according to <2> above, a configuration may be adopted in which the side of the anti-slip protrusion is provided with an arc-shaped portion whose center of curvature is outside the core material and the anti-slip protrusion.

By providing an arc-shaped portion on the side, stress concentration at the base can be more effectively alleviated, and breakage of the core material due to stress concentration on the anti-slip protrusion can be more effectively prevented. In addition, by having the center of curvature of the arc-shaped portion on the outside of the core material and the anti-slip protrusion, the filler is prevented from slipping on the side of the anti-slip protrusion compared to when it is on the inside, and shear fracture of the filler by the anti-slip protrusion is prevented.

<4> In the buckling restraint brace according to <3> above, a configuration may be adopted in which the length of the straight portion is shorter than the radius of curvature of the arc-shaped portion.
<5> In the buckling restraint brace according to <4> above, a configuration may be adopted in which the length of the straight portion is 5 mm or more and 10 mm or less.
<6> In the buckling restraint brace according to <4> or <5> above, a configuration may be adopted in which the radius of curvature of the arc-shaped portion is 15 mm or more and 40 mm or less.

This makes it possible to more effectively alleviate stress concentration at the base, and more effectively prevent breakage of the core material due to stress concentration on the anti-slip projections.
In addition, when the length of the straight portion is 5 mm or more and 10 mm or less, it is possible to prevent a decrease in the strength of the anti-slip projection while mitigating stress concentration at the base. In addition, since the straight portion can be made long, the efficiency of cutting the steel material from the plate is improved.
Furthermore, when the radius of curvature of the arc-shaped portion is 15 mm or more and 40 mm or less, it is possible to reduce stress concentration at the base while ensuring the length of the plasticized region in the core material.

<7> In the buckling restraint brace according to any one of <1> to <6> above, a configuration may be adopted in which the length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material is 20 mm or less.

This makes it possible to more effectively reduce stress concentration on the anti-slip protrusions. In addition, by making the length from the tip to the base of the anti-slip protrusions 20 mm or less, it is possible to prevent a decrease in the efficiency of cutting the steel material from the plate.

<8> In the buckling restraint brace according to any one of <1> to <7> above, the anti-slip protrusions may be provided on both sides of the width of the core material, on both sides of the center of the core material, and the length in the width direction from the tip of one of the anti-slip protrusions to the tip of the other of the anti-slip protrusions provided on each of the core material may be shorter than the width of each of the ends of the core material.

The core material and the anti-slip projections are cut out from a steel plate. The length in the width direction from one tip to the other tip of each of the anti-slip projections is shorter than the width of each of the ends of the core material, which improves the efficiency of cutting the plate from the steel material and therefore improves material yield.

<9> The buckling restraint brace according to any one of <1> to <8> above may further include a stiffening member extending from the core material along the thickness direction of the core material, and the length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material may be shorter than the width of the stiffening member along the width direction of the core material.

This improves the efficiency of cutting steel sheets, thereby improving material yield.

<10> In the buckling restraint brace according to any one of <1> to <9> above, the core material may have a width-changing section whose width narrows toward the center of the core material, and the length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material may be shorter than the narrowing width of the width-changing section.

This improves the efficiency of cutting steel sheets, thereby improving material yield.

<11> The buckling restraint brace according to any one of <1> to <10> above may further include an unbonded material that covers a portion of the core material, and the anti-slip projection may be configured not to be covered by the unbonded material.

This allows the anti-slip protrusions to more effectively prevent the core material from shifting relative to the filler at the center of the core material.

<12> In the buckling restraint brace according to any one of <1> to <7>, <10>, and <11> above, the core material may have a cross-shaped cross section, and the core material may have a first core material plate portion, a second core material plate portion, a third core material plate portion, and a fourth core material plate portion arranged to form the cross shape, the first core material plate portion and the second core material plate portion are arranged in the same plane, the third core material plate portion and the fourth core material plate portion are arranged in the same plane, and the anti-slip projections may be provided on one or both of the first core material plate portion and the second core material plate portion and the third core material plate portion and the fourth core material plate portion.

The core material has a first core material plate portion, a second core material plate portion, a third core material plate portion, and a fourth core material plate portion that are arranged to form a cross-shaped cross section, so that the yield strength of the core material can be improved compared to when the core material is formed from a single steel plate.

<13> In the buckling restraint brace according to any one of <1> to <11> above, the anti-slip projections may be provided on both sides of the width of the core material, on both sides of the center of the core material, and at the same position when viewed along the width direction.

This allows the anti-slip protrusions on both sides of the core material's width to prevent the core material from shifting relative to the filler.

<14> In the buckling restraint brace according to any one of <1> to <7> and <9> to <11> above, the anti-slip projections may be provided on both sides of the core material in the thickness direction by being welded to both sides of the center of the core material.

This allows the anti-slip protrusions to be provided on both sides of the core material in the thickness direction by welding.

The present invention makes it possible to prevent the core material from breaking due to stress concentration on the anti-slip projections.

FIG. 2 is a view of the buckling restraint brace according to the first embodiment, viewed along the thickness direction of the core material. FIG. 2 is a view of the buckling restraint brace according to the first embodiment, viewed along the width direction of the core material. FIG. 4 is an enlarged view of a displacement prevention protrusion according to the first embodiment. FIG. 2 is a partially enlarged view of the core material according to the first embodiment. FIG. 11 is a view of the buckling restraint brace according to the second embodiment, viewed along the thickness direction of the core material. FIG. 11 is a view of the buckling restraint brace according to the second embodiment, viewed along the width direction of the core material. 13 is a view of a buckling restraint brace according to a third embodiment, viewed along the plate thickness direction of the first core plate portion. A diagram showing the buckling restraint brace according to the second embodiment, viewed along the width direction of the first core plate portion.

First Embodiment
Hereinafter, a buckling restraint brace 1 according to a first embodiment of the present invention will be described with reference to FIGS.
The buckling restraint brace 1 is attached to a structure. The buckling restraint brace 1 is used, for example, to reinforce a structure made up of columns and beams in a building.

The buckling restraint brace 1 comprises a core material 10, a stiffening member 20, a restraint member 30, a filler 31, an unbonding material 32, and a projection 40 for preventing slippage.
In the following description of each component of the buckling restraint brace 1, directions may be referred to as the plate thickness direction, width direction, and longitudinal direction based on the core material 10. In the width direction and plate thickness direction, the side toward the core material 10 is referred to as the inside, and the side away from the core material 10 is referred to as the outside.
Fig. 1 is a view of the buckling restrained brace 1 viewed along the thickness direction of the core material 10. Fig. 2 is a view of the buckling restrained brace 1 viewed along the width direction of the core material 10. Fig. 3 is an enlarged view of the anti-slip protrusion 40. Fig. 4 is a partial enlarged view of the core material 10.

The core material 10 is a flat plate made of steel plate. Both ends of the core material 10 are attached to the structure of a building to reinforce the building.
As shown in FIG. 1 , the core material 10 includes a narrow width portion 11 , a wide width portion 12 , and a width-changing portion 13 .

The narrow width portion 11 is located at the center in the longitudinal direction of the core material 10. The wide width portions 12 are located at both ends in the longitudinal direction of the core material 10.
4, the length in the width direction of the narrow width portion 11 is referred to as the width Wc1 of the narrow width portion 11. The length in the width direction of the wide width portion 12 is referred to as the width Wc2 of the wide width portion 12. The width Wc2 of the wide width portion 12 is wider than the width Wc1 of the narrow width portion 11.
The length of the narrow portion 11 along the longitudinal direction is referred to as the length of the narrow portion 11. The length of the wide portion 12 along the longitudinal direction is referred to as the length of the wide portion 12. The length of the wide portion 12 is shorter than the length of the narrow portion 11.
Since the longitudinal center of the core material 10 is narrow width portion 11 and the longitudinal ends are wide width portions 12, the longitudinal center of the core material 10 (i.e., narrow width portion 11) becomes a region that is easily plasticized, and the plasticization region is limited to the center.

The width-changing portion 13 is the boundary region between the wide portion 12 and the narrow portion 11. The length of the width-changing portion 13 in the width direction is referred to as the width of the width-changing portion 13. The width of the width-changing portion 13 changes along the longitudinal direction. The width of the width-changing portion 13 narrows from the wide portion 12 side toward the narrow portion 11 side. In other words, the width of the width-changing portion 13 narrows toward the center of the longitudinal direction of the core material 10. The width-changing portion 13 absorbs, for example, an additional bending moment acting on the core material 10.

The stiffening member 20 is a plate-shaped member made of steel plate. The stiffening member 20 is provided on both ends of the core material 10 (i.e., the wide portion 12). The stiffening member 20 reinforces both ends of the core material 10 and prevents the core material 10 from bending in the thickness direction.

The stiffening member 20 is provided on the front and back surfaces of the wide portion 12 (i.e., the surfaces of the wide portion 12 facing the plate thickness direction). The stiffening member 20 extends from the wide portion 12 along the plate thickness direction of the core material 10. The stiffening member 20 is joined to the wide portion 12 by welding. The core material 10 and the stiffening member 20 have a cross-shaped cross section.

Bolt holes (not shown) are provided in the stiffening member 20 and the wide portion 12. The buckling restraint brace 1 is attached to the structure by bolts (not shown) inserted into the bolt holes.

The restraining member 30 is tubular. For example, the restraining member 30 is a rectangular steel pipe. The restraining member 30 may also be a cylindrical steel pipe.

The restraining member 30 covers the outer periphery of the core material 10. The length of the restraining member 30 along the longitudinal direction is referred to as the length of the restraining member 30. The length of the restraining member 30 is shorter than the length of the entire core material 10 along the longitudinal direction. The length of the restraining member 30 is longer than the length of the narrow width portion 11. As a result, the wide width portion 12 of the core material 10 protrudes outward from the restraining member 30.

The filler 31 is filled between the core material 10 and the restraining member 30. For example, the material of the filler 31 is concrete or mortar. To prevent the filler 31 from leaking out from the ends of the restraining member 30, both end openings of the restraining member 30 are closed with lids (not shown).

The unbond material 32 covers the portions of the core material 10 and the stiffening member 20 that are positioned inside the restraining member 30. The unbond material 32 is provided between the core material 10 and the stiffening member 20 and the filler 31. The unbond material 32 prevents the core material 10 and the stiffening member 20 from adhering to the filler 31. The unbond material 32 allows the core material 10 and the stiffening member 20 to move relative to the filler 31.

By providing the unbonding material 32, the filler 31 holds the core material 10 in a position that allows it to move relative to the restraining member 30 in the longitudinal direction so that the axial force of the core material 10 is not transmitted to the restraining member 30. The restraining member 30 and the filler 31 restrict deformation of the core material 10 in any direction other than the longitudinal direction.

The slip prevention protrusions 40 are provided to prevent the amount of misalignment between the core material 10 and the restraining member 30 (the amount of relative movement of the core material 10 with respect to the restraining member 30) from being equal at both ends due to the influence of the weight of the buckling restraint brace 1, etc. The slip prevention protrusions 40 are provided in the center of the core material 10 in the longitudinal direction. The slip prevention protrusions 40 are provided on both sides of the core material 10 in the width direction. The slip prevention protrusions 40 protrude outward in the width direction from the side surfaces of the core material 10 in the width direction. The material of the slip prevention protrusions 40 is the same as the material of the core material 10. The slip prevention protrusions 40 are formed integrally with the core material 10.

The anti-slip protrusion 40 is covered by the filler 31. The anti-slip protrusion 40 is not covered by the unbond material 32. In other words, the anti-slip protrusion 40 is exposed from the unbond material 32. This makes the anti-slip protrusion 40 unable to move relative to the filler 31. The anti-slip protrusion 40 prevents the core material 10 from shifting out of position relative to the filler 31 at the center of the core material 10.

The slippage prevention protrusions 40 include a first slippage prevention protrusion 41 provided on one side of the core material 10 in the width direction, and a second slippage prevention protrusion 42 provided on the other side of the core material 10 in the width direction. The first slippage prevention protrusion 41 and the second slippage prevention protrusion 42 are positioned so that their longitudinal positions coincide.

The first anti-slip projection 41 and the second anti-slip projection 42 have the same shape. The shapes of the first anti-slip projection 41 and the second anti-slip projection 42 will be collectively described as the shape of the anti-slip projection 40.
Fig. 3 is an enlarged view of the anti-slip projection 40. In Fig. 3, for ease of explanation, the boundary between the core material 10 and the anti-slip projection 40 is shown by a dotted line.

The anti-slip projection 40 has a tip 40a, a base 40b, and a pair of side surfaces 40c connecting the tip 40a and the base 40b. The base 40b is the portion of the anti-slip projection 40 that is connected to the core material 10, and the tip 40a is the portion opposite the base 40b. The tip 40a is located on the outer side of the anti-slip projection 40 in the width direction, and the base 40b is located on the inner side of the anti-slip projection 40 in the width direction. The side surfaces 40c are the surfaces of the anti-slip projection 40 that face the longitudinal direction.

The length of the anti-slip projection 40 along the longitudinal direction of the core material 10 is referred to as the width of the anti-slip projection 40. The width of the anti-slip projection 40 increases from the tip 40a to the base 40b.
Here, when a tensile force is applied in the longitudinal direction to the core material 10, stress is likely to concentrate at the base 40b of the anti-slip protrusion 40, and cracks are likely to occur starting from the base 40b. By increasing the width of the anti-slip protrusion 40 from the tip 40a to the base 40b of the anti-slip protrusion 40, stress concentration at the base 40b of the anti-slip protrusion 40 can be suppressed, and cracks can be suppressed.

The tip 40a includes a linear portion 40a1 that is parallel to the longitudinal direction of the core material 10. The length of the linear portion 40a1 along the longitudinal direction is referred to as the length L of the linear portion 40a1. In other words, the length L of the linear portion 40a1 is the width of the anti-slip projection 40 at the tip 40a.

When viewed from the plate thickness direction, the side surface 40c is arc-shaped. That is, the side surface 40c has an arc-shaped portion 40c1. The center of curvature of the arc-shaped portion 40c1 is C, and the radius of curvature of the arc-shaped portion 40c1 is R. The center of curvature C of the arc-shaped portion 40c1 is located outside the core material 10 and the anti-slip projection 40.

The length L of the linear portion 40a1 is shorter than the radius of curvature R of the arcuate portion 40c1.
For example, the length L of the straight portion 40a1 is preferably 5 mm or more and 10 mm or less. If the length L of the straight portion 40a1 exceeds 10 mm, stress concentration increases at the base 40b of the anti-slip protrusion 40. If the length L of the straight portion 40a1 is less than 5 mm, the width of the anti-slip protrusion 40 at the tip 40a becomes small, and the strength of the anti-slip protrusion 40 decreases.
The radius of curvature R of the arc-shaped portion 40c1 is preferably 15 mm or more and 40 mm or less. If the radius of curvature R of the arc-shaped portion 40c1 is less than 15 mm, stress concentration at the base 40b of the anti-slip projection 40 increases. On the other hand, if the radius of curvature R of the arc-shaped portion 40c1 is large, the length of the plasticized region in the core material 10 decreases. In order to ensure the length of the plasticized region in the core material 10, the radius of curvature R of the arc-shaped portion 40c1 is preferably 40 mm or less.

The length from the tip 40a to the base 40b of the anti-slip protrusion 40 as viewed along the longitudinal direction of the core material 10 is defined as the height H of the anti-slip protrusion 40. In this embodiment, the height H of the anti-slip protrusion 40 is the length along the width direction of the core material 10 from the tip 40a to the base 40b of the anti-slip protrusion 40. For example, the height H of the anti-slip protrusion 40 is 20 mm or less. If the height H of the anti-slip protrusion 40 exceeds 20 mm, stress concentration at the base 40b of the anti-slip protrusion 40 increases.

4, the length of the stiffening member 20 along the width direction of the core material 10 is defined as the width Wh of the stiffening member 20. The height H of the anti-slip projection 40 is shorter than the width Wh of the stiffening member 20.
As described above, the width of width-changing portion 13 narrows from the wide portion 12 toward the narrow portion 11. The narrowed width of width-changing portion 13 is designated as Wc3. The height H of anti-slip protrusion 40 is shorter than the narrowed width Wc3 of width-changing portion 13. In other words, the side surface in the width direction of wide portion 12 is located outward in the width direction than the tip 40a of anti-slip protrusion 40.

As shown in FIG. 4, the length along the width direction of the core material 10 from the tip 40a of the first anti-slip projection 41 to the tip 40a of the second anti-slip projection 42 is the tip-to-tip length Wp. The tip-to-tip length Wp is shorter than the width Wc2 of the wide portion 12 (i.e., the width of each of the two end portions of the core material 10).

As described above, the buckling restraint brace 1 according to this embodiment comprises a core material 10, a restraining member 30 that covers the outer periphery of the core material 10, and a filler 31 that is filled between the core material 10 and the restraining member 30 and covers the core material 10. A slippage prevention protrusion 40 for preventing slippage of the core material 10 is provided in the center of the core material 10. The slippage prevention protrusion 40 is covered with the filler 31. The width of the slippage prevention protrusion 40 increases from the tip 40a of the slippage prevention protrusion 40 toward the base 40b of the slippage prevention protrusion 40.

Due to manufacturing errors in the buckling restraint brace 1 and the influence of the buckling restraint brace 1's own weight, the longitudinal displacement of the core material 10 when a longitudinal compressive force or tensile force is applied to the core material 10 may be asymmetric between one side and the other side of the core material 10. By providing the anti-slip protrusions 40, the core material 10 is prevented from shifting relative to the filler 31 at the center of the core material 10. As a result, when a longitudinal compressive force is applied to the core material 10, the core material 10 shrinks toward the center of the core material 10 (anti-slip protrusions 40), and the longitudinal displacement of the core material 10 can be made symmetric between one side and the other side of the core material 10 in the longitudinal direction.

In addition, by increasing the width of the anti-slip projection 40 from the tip 40a to the base 40b, the base 40b, where stress is likely to concentrate, can be made relatively thick, dispersing stress at the base 40b and making cracks less likely to occur. This makes it possible to suppress the occurrence of cracks originating from the base 40b and to suppress breakage of the core material 10 caused by such cracks, thereby improving the fatigue properties of the core material 10 against repeated earthquakes.

Further, the tip 40 a includes a linear portion 40 a 1 that is parallel to the longitudinal direction of the core material 10 .
The anti-slip projection 40 is formed by cutting out from a steel plate. Since the tip 40a includes the linear portion 40a1, the efficiency of cutting out the plate from the steel material is improved, and the material yield can be improved.

Further, the side surface 40 c of the anti-slip projection 40 is provided with an arc-shaped portion 40 c 1 whose center of curvature C is located outside the core material 10 and the anti-slip projection 40 .
By providing the arc-shaped portion 40c1 on the side surface 40c, stress concentration at the base 40b can be more effectively alleviated, and breakage of the core material 10 due to stress concentration on the anti-slip protrusion 40 can be more effectively suppressed. Furthermore, when the center of curvature of the arc-shaped portion is on the inside of the core material 10 and the anti-slip protrusion 40, the filler 31 tends to slide on the side surface 40c of the anti-slip protrusion 40, making the filler 31 more likely to undergo shear fracture. By having the center of curvature C of the arc-shaped portion 40c1 on the outside of the core material 10 and the anti-slip protrusion 40, the filler 31 is prevented from sliding on the side surface 40c of the anti-slip protrusion 40, and shear fracture of the filler 31 by the anti-slip protrusion 40 is suppressed, compared to when it is on the inside.

Additionally, the length L of the linear portion 40a1 is shorter than the radius of curvature R of the arcuate portion 40c1.
The length L of the linear portion 40a1 is not less than 5 mm and not more than 10 mm.
The radius of curvature R of the arcuate portion 40c1 is not less than 15 mm and not more than 40 mm.
This makes it possible to more effectively alleviate stress concentration at the base 40b, and more effectively prevent breakage of the core material 10 due to stress concentration on the anti-slip projections 40.
Furthermore, when the length L of the straight portion 40a1 is 5 mm or more and 10 mm or less, it is possible to alleviate stress concentration at the base 40b while preventing a decrease in the strength of the anti-slip projection 40. Furthermore, since the straight portion 40a1 can be made long, the efficiency of cutting the steel material is improved.
Furthermore, when the radius of curvature R of the arc-shaped portion 40c1 is 15 mm or more and 40 mm or less, the length of the plasticized region in the core material 10 can be ensured while stress concentration at the base 40b can be alleviated.

Furthermore, the length from the tip 40a to the base 40b of the anti-slip projection 40 as viewed along the longitudinal direction of the core material 10 (height H of the anti-slip projection 40) is 20 mm or less.
This makes it possible to more effectively alleviate stress concentration on the anti-slip projection 40. Furthermore, by making the length from the tip 40a to the base 40b of the anti-slip projection 40 20 mm or less, it is possible to prevent a decrease in the efficiency of cutting the plate from the steel material.

The anti-slip projections 40 are provided on both sides in the width direction of the core material 10, on both sides of the center of the core material 10. The length in the width direction from one tip 40a to the other tip 40a of each of the anti-slip projections 40 (tip-to-tip length Wp) is shorter than the width of each of the end portions of the core material 10 (Wc2 of the wide portion 12).
The core material 10 and the anti-slip projections 40 are formed by cutting out from a steel plate. The length in the width direction from one tip 40a to the other tip 40a of each of the anti-slip projections 40 is shorter than the width of each of the two ends of the core material 10, which improves the efficiency of cutting the plate from the steel material and therefore improves the material yield.

The buckling restraint brace 1 further includes a stiffening member 20 extending from the core material 10 along the thickness direction of the core material 10. The length from the tip 40a to the base 40b of the anti-slip protrusion 40 as viewed along the longitudinal direction of the core material 10 (height H of the anti-slip protrusion 40) is shorter than the width Wh of the stiffening member 20, which is the width along the width direction of the core material 10.
This improves the efficiency of cutting steel sheets, thereby improving material yield.

Additionally, the core material 10 includes a width varying portion 13 whose width narrows toward the center of the core material 10. The length from the tip 40a to the base 40b of the anti-slip projection 40 as viewed along the longitudinal direction of the core material 10 (height H of the anti-slip projection 40) is shorter than the narrowing width Wc3 of the width varying portion 13.
This improves the efficiency of cutting steel sheets, thereby improving material yield.

The buckling restraint brace 1 further includes an unbond material 32 that covers a portion of the core material 10. The anti-slip protrusion 40 is not covered by the unbond material 32.
As a result, the anti-slip projection 40 can more effectively prevent the core material 10 from shifting relative to the filler 31 at the center of the core material 10 .

The anti-slip projections 40 are provided on both sides of the width of the core material 10, on both sides of the center of the core material 10, and at the same position when viewed along the width direction.
As a result, the anti-slip projections 40 can prevent the core material 10 from shifting relative to the filler 31 from both sides in the width direction of the core material 10 .

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

A finite element analysis was performed to verify the effect of the anti-slip protrusions 40 in reducing cumulative damage due to ultra-low cycle fatigue (ULCF) when the shape of the anti-slip protrusions 40 (length L of the straight portion 40a1, height H of the anti-slip protrusions 40, and radius of curvature R of the arc-shaped portion 40c1) was changed.

Table 1 shows the length L of the straight portion 40a1, the height H of the anti-slip projection 40, and the radius of curvature R of the arcuate portion 40c1 in Examples 1 to 3 and Comparative Examples 1 to 3, as well as the analysis results of the cumulative damage (ULCF damage) of the anti-slip projection 40. In all of Examples 1 to 3 and Comparative Examples 1 to 3, the thickness of the anti-slip projection 40 was 25 mm. In all of Examples 1 to 3 and Comparative Examples 1 to 3, the anti-slip projection 40 was integrally formed with the core material 10 (i.e., the anti-slip projection 40 and the core material 10 were not welded). In Table 1, the cumulative damage (ULCF damage) of the anti-slip projection 40 is shown based on Comparative Example 1. In other words, the smaller the cumulative damage (ULCF damage) value of the anti-slip protrusion 40, the more the cumulative damage to the anti-slip protrusion 40 is reduced compared to Comparative Example 1.

As shown in Table 1, when the length L of the straight portion 40a1 is 5 mm or more and 10 mm or less, the cumulative damage of the anti-slip projection 40 is reduced by 24% or more based on Comparative Example 1, that is, the cumulative damage of the anti-slip projection 40 is significantly reduced. When the length L of the straight portion 40a1 is 5 mm or more and 10 mm or less, the stress concentration at the base 40b is effectively alleviated, and therefore the cumulative damage of the anti-slip projection 40 is significantly reduced. In addition, when comparing Example 2 and Example 3, the cumulative damage of the anti-slip projection 40 is significantly reduced in both cases, but when the radius of curvature R of the arcuate portion 40c1 is 15 mm, the cumulative damage of the anti-slip projection 40 is more significantly reduced.

Second Embodiment
Next, a buckling restrained brace 1A according to a second embodiment of the present invention will be described with reference to Figures 5 and 6. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and their description will be omitted, and only the differences will be described.
Fig. 5 is a view of the buckling restrained brace 1A viewed along the thickness direction of the core material 10. Fig. 6 is a view of the buckling restrained brace 1A viewed along the width direction of the core material 10.

In this embodiment, the buckling restraint brace 1A has anti-slip protrusions 50 instead of anti-slip protrusions 40.
5 and 6, anti-slip protrusions 50 are provided on both sides in the thickness direction of core material 10. Anti-slip protrusions 50 protrude outward in the thickness direction from the front and back surfaces of core material 10 (i.e., the surfaces of core material 10 facing the thickness direction). Anti-slip protrusions 50 are disposed in the center of core material 10 in the longitudinal direction and the center of core material 10 in the width direction. Anti-slip protrusions 50 are joined to core material 10 by welding.

The slippage prevention protrusions 50 include a first slippage prevention protrusion 51 provided on one side of the core material 10 in the thickness direction, and a second slippage prevention protrusion 52 provided on the other side of the core material 10 in the thickness direction. The first slippage prevention protrusion 51 and the second slippage prevention protrusion 52 are positioned so that their longitudinal positions coincide. The first slippage prevention protrusion 51 and the second slippage prevention protrusion 52 have the same shape.

The anti-slip protrusion 50 has the same shape as the anti-slip protrusion 40. That is, the anti-slip protrusion 50 has a tip, a base, and a pair of side surfaces connecting the tip and the base. The base is the portion of the anti-slip protrusion 50 that is connected to the core material 10 (in this embodiment, the portion that is welded to the core material 10), and the tip is the portion opposite the base. The tip is located on the outside of the anti-slip protrusion 50 in the plate thickness direction, and the base is located on the inside of the anti-slip protrusion 50 in the plate thickness direction. The side surfaces are surfaces of the anti-slip protrusion 50 that face the longitudinal direction.
The width of the anti-slip projection 50 increases from the tip to the base. The tip of the anti-slip projection 50 includes a straight portion parallel to the longitudinal direction of the core material 10. The side surface of the anti-slip projection 50 is provided with an arc-shaped portion whose center of curvature is outside the core material 10 and the anti-slip projection 50.

As described above, in the buckling restraint brace 1A according to this embodiment, the anti-slip projections 50 are provided on both sides of the core material 10 in the thickness direction by being welded to both sides of the central part of the core material 10.

The buckling restrained brace 1A of this embodiment can achieve the same effects as the buckling restrained brace 1 of the first embodiment.
That is, by increasing the width of the anti-slip projection 50 from the tip to the base, the base of the anti-slip projection 50, where stress is likely to concentrate, can be made relatively thick, dispersing stress and making cracks less likely to occur at the base of the anti-slip projection 50. This makes it possible to suppress the occurrence of cracks originating from the base of the anti-slip projection 50 and to suppress breakage of the core material 10 caused by such cracks, thereby improving the fatigue properties of the core material 10 against repeated earthquakes.
In addition, anti-slip projections 50 can be provided on both sides of the core material 10 in the thickness direction by welding.

Third Embodiment
Next, a buckling restrained brace 1B according to a third embodiment of the present invention will be described with reference to Figures 7 and 8. In this embodiment, the same components as those in the first embodiment are given the same reference numerals, and their description will be omitted, and only the differences will be described.

In this embodiment, the buckling restraint brace 1B has a core material 60 with a cross-shaped cross section instead of the core material 10 and stiffening member 20. The buckling restraint brace 1B also has a slippage prevention protrusion 70 instead of the slippage prevention protrusion 40.

The core 60 has a first core plate 61, a second core plate 62, a third core plate 63, and a fourth core plate 64. The first core plate 61, the second core plate 62, the third core plate 63, and the fourth core plate 64 are arranged to form a cross shape. That is, the first core plate 61 and the second core plate 62 are arranged in the same plane. The third core plate 63 and the fourth core plate 64 are arranged in the same plane. The first core plate 61 and the second core plate 62 are arranged so as to be perpendicular to the third core plate 63 and the fourth core plate 64. Each of the first to fourth core plate portions 61 to 64 has a narrow width portion 11 located in the center in the longitudinal direction, a wide width portion 12 located at both ends in the longitudinal direction, and a width changing portion 13 which is the boundary area between the wide width portion 12 and the narrow width portion 11.
For example, the first core material plate portion 61 and the second core material plate portion 62 may be formed from a single steel plate, and the third core material plate portion 63 and the fourth core material plate portion 64, each made of a different steel plate, may be joined to the front and back surfaces of this steel plate by welding, thereby forming the core material 60.

The anti-slip projections 70 are provided on both the first core plate portion 61 and the second core plate portion 62 and the third core plate portion 63 and the fourth core plate portion 64. That is, the anti-slip projections 70 include a first anti-slip projection 71 provided on the first core plate portion 61, a second anti-slip projection 72 provided on the second core plate portion 62, a third anti-slip projection 73 provided on the third core plate portion 63, and a fourth anti-slip projection 74 provided on the fourth core plate portion 64. The first to fourth anti-slip projections 71 to 74 are integrally formed with the first to fourth core plate portions 61 to 64, respectively.

The first to fourth anti-slip projections 71 to 74 are provided in the longitudinal center of the first to fourth core plate portions 61 to 64, respectively. The first to fourth anti-slip projections 71 to 74 protrude outward in the width direction from the widthwise side surfaces of the first to fourth core plate portions 61 to 64, respectively. The first to fourth anti-slip projections 71 to 74 are positioned so that their longitudinal positions are aligned. The first to fourth anti-slip projections 71 to 74 have the same shape.

The anti-slip projections 70 may be provided on only one of the first core plate portion 61 and the second core plate portion 62, and the third core plate portion 63 and the fourth core plate portion 64. That is, the anti-slip projections 70 may include only the first anti-slip projections 71 and the second anti-slip projections 72. The anti-slip projections 70 may include only the third anti-slip projections 73 and the fourth anti-slip projections 74.

The anti-slip protrusion 70 has the same shape as the anti-slip protrusion 40. That is, the anti-slip protrusion 70 has a tip, a base, and a pair of side surfaces connecting the tip and the base. The base is the portion of the anti-slip protrusion 70 that is connected to the core material 60, and the tip is the portion opposite the base. The side surfaces are the surfaces of the anti-slip protrusion 70 that face in the longitudinal direction.
The width of the anti-slip protrusion 70 increases from the tip to the base. The tip of the anti-slip protrusion 70 includes a straight portion parallel to the longitudinal direction of the core material 60. The side surface of the anti-slip protrusion 70 is provided with an arc-shaped portion whose center of curvature is outside the core material 60 and the anti-slip protrusion 70.

As described above, in the buckling restraint brace 1B according to this embodiment, the core material 60 has a cross-shaped cross section. The core material 60 has a first core material plate portion 61, a second core material plate portion 62, a third core material plate portion 63, and a fourth core material plate portion 64, which are arranged to form a cross-shaped cross section. The first core material plate portion 61 and the second core material plate portion 62 are arranged in the same plane, and the third core material plate portion 63 and the fourth core material plate portion 64 are arranged in the same plane. The anti-slip projections 70 are provided on one or both of the first core material plate portion 61 and the second core material plate portion 62 and the third core material plate portion 63 and the fourth core material plate portion 64.

The buckling restraint brace 1B of this embodiment can achieve the same effects as the buckling restraint brace 1 of the first embodiment.
That is, by increasing the width of anti-slip protrusion 70 from the tip to the base of anti-slip protrusion 70, the base of anti-slip protrusion 70, where stress is likely to concentrate, can be made relatively thick, so that stress is dispersed and cracks are less likely to occur at the base of anti-slip protrusion 70. This makes it possible to suppress the occurrence of cracks originating from the base of anti-slip protrusion 70 and to suppress breakage of core material 60 caused by such cracks, thereby improving the fatigue properties of core material 60 against repeated earthquakes.
In addition, since the core material 60 has the first core material plate portion 61, the second core material plate portion 62, the third core material plate portion 63, and the fourth core material plate portion 64, which are arranged to form a cross-shaped cross section, the yield strength of the core material 60 can be improved compared to when the core material is formed from a single steel plate.

The present invention is not limited to the above-described embodiment described with reference to the drawings, and various modifications are possible within the technical scope.

For example, in the first or second embodiment, a plurality of core materials 10 may be provided parallel to each other. In this case, the plurality of core materials 10 are each provided with the anti-slip projections 40, 50.
In the third embodiment, a plurality of first core plate portions 61 and a plurality of second core plate portions 62 may be provided parallel to each other. In this case, a slippage prevention protrusion 70 is provided on each of the plurality of first core plate portions 61 and the plurality of second core plate portions 62. A plurality of third core plate portions 63 and a plurality of fourth core plate portions 64 may be provided parallel to each other. In this case, a slippage prevention protrusion 70 is provided on each of the plurality of third core plate portions 63 and the plurality of fourth core plate portions 64.

In addition, the components in the above embodiment may be replaced with well-known components as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be combined as appropriate.

Reference Signs List 1, 1A, 1B Buckling restraint brace 10, 60 Core material 11 Narrow width portion 12 Wide width portion 13 Width changing portion 20 Stiffening member 30 Restraint member 31 Filler 32 Unbond material 40, 50, 70 Anti-slip projection 40a Tip 40a1 Straight portion 40b Base 40c Side 40c1 Arc-shaped portion 61 First core material plate portion 62 Second core material plate portion 63 Third core material plate portion 64 Fourth core material plate portion

Claims (14)

A core material;
A restraining member covering an outer periphery of the core material;
A filler that is filled between the core material and the restraining member and covers the core material;
A buckling restraint brace for attachment to a structure, comprising:
A projection for preventing slippage of the core material is provided at the center of the core material,
The anti-slip projection is covered with the filler,
The width of the anti-slip projection increases from the tip of the anti-slip projection to the base of the anti-slip projection.
A buckling restrained brace characterized by: The tip includes a linear portion parallel to the longitudinal direction of the core material.
2. The buckling restrained brace of claim 1. An arc-shaped portion having a center of curvature located outside the core material and the anti-slip projection is provided on a side surface of the anti-slip projection.
3. The buckling restrained brace of claim 2. The length of the linear portion is shorter than the radius of curvature of the arc portion.
4. The buckling restrained brace of claim 3. The length of the linear portion is 5 mm or more and 10 mm or less.
5. The buckling restrained brace of claim 4. The radius of curvature of the arcuate portion is 15 mm or more and 40 mm or less.
6. The buckling restrained brace of claim 5. The length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material is 20 mm or less.
7. The buckling restrained brace of claim 6. The anti-slip projections are provided on both sides of the width direction of the core material and on both sides of a center portion of the core material,
The length in the width direction from the tip of one of the anti-slip projections to the tip of the other of the anti-slip projections is shorter than the width of each of both ends of the core material.
8. The buckling restrained brace of claim 1 . A stiffening member extending from the core material along a thickness direction of the core material;
Further comprising:
The length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material is shorter than the width of the stiffening member as viewed along the width direction of the core material.
8. The buckling restrained brace of claim 1 . The core material has a width change portion in which the width becomes narrower toward the center of the core material;
Equipped with
The length from the tip to the base of the anti-slip projection as viewed along the longitudinal direction of the core material is shorter than the narrowed width of the width changing portion.
8. The buckling restrained brace of claim 1 . an unbond material covering a portion of the core material;
Further comprising:
The anti-slip projection is not covered by the unbond material.
8. The buckling restrained brace of claim 1 . The core material has a cross-shaped cross section,
the core material has a first core material plate portion, a second core material plate portion, a third core material plate portion, and a fourth core material plate portion arranged to form the cross shape,
The first core plate and the second core plate are disposed in the same plane,
The third core plate portion and the fourth core plate portion are disposed in the same plane,
The anti-slip projection is provided on one or both of the first core plate portion and the second core plate portion, and the third core plate portion and the fourth core plate portion.
8. The buckling restrained brace of claim 1 . The anti-slip projections are provided on both sides of the width direction of the core material, on both sides of the center of the core material, and are provided at the same position as viewed along the width direction.
8. The buckling restrained brace of claim 1 . The anti-slip projections are provided on both sides of the core material in the thickness direction by being welded to both sides of the central portion of the core material.
8. The buckling restrained brace of claim 1 .

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