Buckling-restrained brace

Abstract

To provide a buckling-restrained brace capable of sufficiently exhibiting the axial strength of a core member against axial compressive loads.SOLUTION: A buckling-restrained brace 100 comprises: an elongate core member 10; a covering member 50 that covers the surface of the core member 10; a tubular restraining member 30 that houses the core member 10 such that both ends thereof protrude; and a filler 40 filled between the restraining member 30 and the core member 10. The core member 10 comprises a plasticized portion 11 having a smaller cross-sectional area than both end portions. The covering member 50 is in close contact with the surface of the core member 10 in the region where the filler 40 is present along the longitudinal direction of the core member 10. The thickness of a portion of the covering member corresponding to the plasticized portion 11 is constant in the longitudinal direction of the core member 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Buckling-restrained braces have been used as reinforcement 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., so that the core material undergoes 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. The buckling restraint brace in Patent Document 1 discloses a buckling restraint brace that includes a core material, restraint materials made of square steel pipes provided on each surface of the core material perpendicular to the weak axis direction, and unbonded materials arranged between the core material and the restraint materials, with the unbonded materials provided with a gap in the direction of the short side of the core material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-93904 Summary of the Invention [Problem to be solved by the invention]

[0004] According to Patent Document 1, by providing gaps between the unbonded materials, it is possible to prevent the unbonded materials from overlapping each other, thereby preventing the occurrence of locations where the thickness of the unbonded material differs from the designed thickness. In a buckling restrained brace, it is preferable that the distance between the core material and the restraining material is constant along the length of the core material. For example, if there is a location where the distance is greater than the surrounding area, local buckling may occur at that location. This may result in a large localized out-of-plane deformation at that location, causing the core material to break and preventing the core material from fully exerting its axial strength. Here, the core material of the buckling restraint brace is generally made of steel material several thousand mm in length. In addition, in Patent Document 1, square steel pipes are used as the restraint materials. It is difficult to maintain a constant separation distance between the core material and the square steel pipes over the aforementioned length because the core material and the square steel pipes are required to have very high accuracy of straightness.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a buckling restraint brace that can fully exert the axial strength of the core material against axial compressive loads. [Means for solving the problem]

[0006] <1> The buckling restraint brace of aspect 1 of the present invention is a buckling restraint brace comprising a long core material, a covering member that covers the surface of the core material, a tubular restraint member that contains the core material with both ends protruding, and a filler material that is filled between the restraint member and the core material, wherein the core material has a plasticized portion having a smaller cross-sectional area than both ends, the covering member is in close contact with the surface of the core material in the range in the longitudinal direction of the core material where the filling material is present, and the thickness of the portion corresponding to the plasticized portion is constant in the longitudinal direction of the core material.

[0007] According to the first aspect, the space between the restraining member and the core material is filled with a filler material. This makes it easier to keep the distance between the core material and the filler material constant along the length of the core material, compared to when the core material is restrained by a square steel pipe or the like. In addition, the covering member is in close contact with the surface of the core material in the range where the filler is present in the longitudinal direction of the core material. This results in the covering member being interposed between the core material and the filler. This makes it possible to prevent the core material and the filler from coming into direct contact with each other. Therefore, when the core material deforms due to the application of a load, interference between the core material and the filler, or the filler following the deformation of the core material, can be prevented, and deformation of the filler can be prevented.

[0008] Here, if there is a location where the distance between the plasticized portion and the filling material is partially large, that location may be significantly deformed (buckled) when an axial compressive load is input to the core material. Therefore, the thickness of the covering member at the portion corresponding to the plasticized portion is constant in the longitudinal direction of the core material. This makes it possible to make the distance between the plasticized portion of the core material and the filling material constant along the longitudinal direction. Therefore, when an axial compressive load is input to the core material, it is possible to prevent significant deformation (buckling) in the portions of the core material where the distance between the plasticized portion and the filling material is partially large. Therefore, it is possible to prevent extremely large strain from occurring locally in the plasticized portion of the core material, and to uniformize the longitudinal strain distribution in the core material. In other words, it is possible to generate strain evenly along the longitudinal direction of the core material. In addition, it is possible to uniformize the load applied to the plasticized portion of the core material in the longitudinal direction. Therefore, the axial strength of the core material can be fully exerted against the axial compressive load. This improves the fatigue properties of the core material, making it easier to prevent breakage due to repeated compressive and tensile loads during an earthquake. Effect of the Invention

[0009] According to the present invention, it is possible to provide a buckling restrained brace that can fully exert the axial strength of the core material against axial compressive load. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view of a buckling restraint brace according to an embodiment of the present invention when viewed from the front. [Diagram 2] FIG. 2 is an exploded perspective view of a buckling restraint brace according to an embodiment. [Diagram 3] 4 is an enlarged view of the periphery of a protrusion provided on a core material. FIG. [Figure 4] 13 is a diagram showing a state in which a plurality of sheet-like members forming a covering member are provided on a core material with their end faces butted against each other. FIG. [Diagram 5] 4 is a cross-sectional view showing the positional relationship between the core material and the covering member at an end portion of the core material in the plate width direction. FIG. [Figure 6] FIG. 2 is a cross-sectional view perpendicular to the longitudinal direction of the buckling restraint brace, showing a portion corresponding to the plasticized portion of the core material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A buckling restrained brace 100 according to one embodiment of the present invention will now be described with reference to the drawings. The buckling restrained brace 100 is attached to a structure. The buckling restrained brace 100 is used, for example, to reinforce a structure made up of columns and beams in a building. In other words, the buckling restrained brace 100 is used as a diagonal brace in the building. FIG. 1 is a cross-sectional front view of a buckling restrained brace 100 according to an embodiment. FIG. 2 is an exploded perspective view of the buckling restraint brace 100 according to an embodiment. As shown in FIGS. 1 and 2, the buckling restrained brace 100 includes a core material 10, stiffening members 20, restraining members 30, a filling material 40, and a covering member 50.

[0012] The core material 10 is a long member. In this embodiment, the core material 10 is plate-shaped. More specifically, the core material 10 is a flat plate made of steel plate. The core material 10 reinforces the building by having both ends attached to the structure of the building. 1, the core material 10 includes a plasticized portion 11, a wide portion 12, and a width-changing portion 13. In this embodiment, the core material 10 is formed, for example, by cutting it out from a single flat plate.

[0013] The plasticized portion 11 is located at the center of the core material 10 in the longitudinal direction. The wide portions 12 are located at both ends of the core material 10 in the longitudinal direction. In this embodiment, the length of the plasticized portion 11 in the longitudinal direction is longer than the length of the wide portion 12 in the longitudinal direction. In the core material 10, the cross-sectional area of ​​the plasticized portion 11 is smaller than the cross-sectional area of ​​the wide portions 12 located at both ends of the core material 10. That is, in this embodiment in which the core material 10 is a flat plate, the plate thicknesses of the plasticized portion 11 and the wide portions 12 are the same. The plate width of the plasticized portion 11 is smaller than the plate width of the wide portions 12. By providing core material 10 with the above-mentioned shape, when an axial compressive load is applied to core material 10, plasticized portion 11 is deformed before other portions of core material 10, and deformation of portions other than plasticized portion 11 can be suppressed. In other words, the center of core material 10 in the longitudinal direction (i.e., plasticized portion 11) becomes a region that is easily plasticized, and the plasticized region is limited to the center. It is preferable that the plasticized portion 11 has a constant cross-sectional shape along the longitudinal direction in order to make constant the load applied to each portion and the amount of strain caused by the load.

[0014] FIG. 3 is an enlarged view of the periphery of a protrusion 11p provided on the core material 10. As shown in FIG. 3, the plasticized portion 11 includes a protrusion 11p. The protrusion 11p is a portion that protrudes from the plasticized portion 11 of the core material 10 toward the covering member 50. The protrusion 11p is 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 100, etc. The protrusion 11p is provided in the center of the core material 10 in the longitudinal direction. The protrusion 11p is provided on both sides of the core material 10 in the width direction. The protrusions 11p provided on both sides of the core material 10 in the width direction are arranged so that their positions in the longitudinal direction of the core material 10 coincide. The protrusion 11p protrudes along the width direction from the side surface of the core material 10 in the width direction. The material of the protrusion 11p is the same as the material of the core material 10. The protrusion 11p is formed integrally with the core material 10. That is, the protrusion 11p is formed, for example, by cutting out from a flat plate together with the plasticized portion 11.

[0015] The protrusion 11p is covered by the filler 40. The protrusion 11p is not covered by the covering member 50. That is, the protrusion 11p is exposed from the covering member 50, and at least its tip 11t is covered by the filler 40. Here, the filler 40 is formed of a material described later, and does not deform after hardening. Therefore, the tip 11t of the protrusion 11p covered by the filler 40 is supported by the hardened filler 40, and cannot move relative to the filler 40. In this way, the protrusion 11p prevents the core material 10 from being displaced relative to the filler 40 at the center of the core material 10.

[0016] As shown in FIG. 3, the width of the protrusion 11p increases from the tip 11t toward the base 11r of the protrusion 11p. This allows the base 11r of the protrusion 11p, where stress is likely to concentrate, to be made wider relative to the tip 11t. Thus, stress is dispersed at the base 11r of the protrusion 11p, making it possible to form a shape that is less susceptible to cracking. This makes it possible to suppress the occurrence of cracks originating from the base 11r of the protrusion 11p, suppress breakage of the core material 10 due to such cracks, and improve the fatigue properties of the core material 10 against repeated earthquakes.

[0017] In this embodiment, the protrusion 11p may have any shape, such as a cylindrical shape, a prismatic shape, a truncated cone shape, or a truncated pyramid shape. When the protrusion 11p is in the shape of a truncated cone or a truncated pyramid, the side surface connecting the upper base and the lower base may be formed in an arc shape as shown in Fig. 3. In this case, stress concentration can be made less likely to occur at the base 11r of the protrusion 11p protruding from the plasticized portion 11.

[0018] The width-changing portion 13 is a boundary region between the wide portion 12 and the plasticized portion 11. The length in the width direction of the width-changing portion 13 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 toward the plasticized portion 11. That is, the width of the width-changing portion 13 narrows toward the center of the core material 10 in the longitudinal direction. The width changing portion 13 absorbs, for example, an additional bending moment acting on the core material 10 .

[0019] The stiffening members 20 are plate-shaped members made of steel plates. The stiffening members 20 are provided on both ends (i.e., the wide portions 12) of the core material 10. The stiffening members 20 reinforce both ends of the core material 10 and prevent the core material 10 from bending in the thickness direction.

[0020] The stiffening members 20 are provided on the front and back surfaces of the wide portion 12 (i.e., the surfaces facing the plate thickness direction of the wide portion 12). The stiffening members 20 extend from the wide portion 12 along the plate thickness direction of the core material 10. The stiffening members 20 are joined to the wide portion 12 by welding. The core material 10 and the stiffening members 20 have a cross-shaped cross section.

[0021] Bolt holes (not shown) are formed in the stiffening member 20 and the wide portion 12. The buckling restraint brace 100 is attached to a structure by bolts (not shown) that are inserted into the bolt holes.

[0022] The restraining member 30 is a tubular member that houses the core material 10 with both ends protruding. For example, a steel pipe is used for the restraining member 30. That is, the restraining member 30 may be a square steel pipe or a cylindrical steel pipe. In this embodiment, a cylindrical steel pipe is used for the restraining member 30 as shown in Figs. 1 and 2.

[0023] The restraining member 30 covers the outer periphery of the core material 10. 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 plasticized portion 11. As a result, the wide portion 12 of the core material 10 protrudes outward from the restraining member 30.

[0024] The filler 40 is filled between the restraining member 30 and the core material 10. For example, the material of the filler 40 is concrete or mortar. In order to prevent the filler 40 from leaking out from the ends of the restraining member 30, both end openings of the restraining member 30 are closed by lids (not shown). The filler 40 is injected into the space inside the restraining member 30 in a state in which the core material 10 to which the stiffening members 20 and the covering members 50 are attached is placed inside the restraining member 30. The filler 40 then hardens, thereby fixing the core material 10 and the restraining member 30 together. Before hardening, the filler 40 can be appropriately deformed to match the shape of the core material 10. This makes it possible to keep the distance between the core material 10 and the filler 40 constant throughout the longitudinal direction of the core material 10, even if there is a distribution in the thickness of the core material 10 within the range of intersection.

[0025] FIG. 4 is a diagram showing a state in which a plurality of sheet-like members forming the covering member 50 are provided on the core material 10 with their end faces butted against each other. FIG. 5 is a cross-sectional view showing the positional relationship between the core material 10 and the covering member 50 at an end portion of the core material 10 in the plate width direction. The covering member 50 covers the surface of the core material 10. The covering member 50 is in close contact with the surface of the core material 10 in the range in the longitudinal direction of the core material 10 where the filler material 40 is present. In other words, the covering member 50 covers the portions of the core material 10 and the stiffening member 20 that are disposed inside the restraining member 30. The covering member 50 is provided between the core material 10 and the stiffening member 20 and the filler material 40. The covering member 50 prevents the core material 10 and the stiffening member 20 and the filler material 40 from adhering to one another. The covering member 50 allows the core material 10 and the stiffening member 20 to move relative to the filling material 40 .

[0026] By providing the covering member 50, the filler 40 holds the core material 10 so that it can 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 40 restrict deformation of the core material 10 in directions other than the longitudinal direction.

[0027] That is, by interposing the covering member 50 between the core material 10 and the stiffening member 20 and the filling material 40, when the core material 10 deforms due to the application of a load, it is possible to prevent the core material 10 and the filling material 40 from interfering with each other, or the filling material 40 from following the deformation of the core material 10. This makes it possible to prevent the deformation of the filling material 40. In addition, when an axial compressive load is applied to the core material 10, the core material 10 contracts due to vertical strain and at the same time the outer surface of the core material 10 moves so as to expand due to horizontal strain, it is possible to prevent the outer surface of the core material 10 from interfering with the filling material 40.

[0028] In this embodiment, the thickness of the covering member 50 at the portion corresponding to the plasticized portion 11 of the core material 10 is constant in the longitudinal direction of the core material 10. In this embodiment, the constant thickness of the covering member 50 means that the member used as the covering member 50 has a constant thickness. That is, for example, when filling the space between the restraining member 30 and the core material 10 with the filler 40, the thickness of the covering member 50 may change due to the weight of the filler 40, resulting in a slight difference in thickness in the longitudinal direction of the core material 10, but in such a case, the thickness of the covering member 50 is considered to be constant. This allows the covering member 50 to keep the distance between the core material 10 and the filler material 40 constant along the longitudinal direction of the core material 10 . When an axial compressive load is applied to the core material 10, the core material 10 shrinks due to vertical strain. Then, the core material 10 is deformed so as to expand due to horizontal strain. This causes the outer peripheral surface of the core material 10 to approach the filler material 40. In this case, the ratio of the amount of approach of the side surface of the core material 10 in the plate width direction to the filler material 40 and the amount of approach of the side surface of the core material 10 in the plate thickness direction to the filler material 40 is the same as the ratio of the plate width of the core material 10 to the plate thickness of the core material 10.

[0029] In this embodiment, the covering member 50 is an elastic member. The elastic member is a plurality of sheets. That is, the covering member 50 is formed by attaching a plurality of sheet-like elastic members to the core material 10. The elastic member forming the sheet-like member preferably has the following properties, for example. In other words, it is preferable that the sheet-like elastic member, for example, when attached to the outer surface of core material 10, be capable of deforming to an extent that no gap is created between core material 10 and covering member 50 along the outer surface of core material 10, which is not completely flat, and also have a hardness sufficient to retain its shape when filler 40 is injected between core material 10 and restraining member 30. Furthermore, the sheet-like elastic member preferably has an adhesive property that allows it to be attached without gaps to the internal corners of the L-shaped cross section of the core material 10 provided with the stiffening members 20. That is, for example, the sheet-like elastic member preferably has a penetration of 50 to 77 as defined in JIS K 2207. Examples of sheet-like members that satisfy the above-mentioned performance include the following: That is, as the elastic sheet-like member, any of butyl rubber, viscoelastic plastic, natural rubber, polyisoprene, polybutadiene, styrene butadiene rubber, ethylene propylene rubber, polychloroprene, polyisobutylene, asphalt, paint, and mixtures thereof can be appropriately selected and used.

[0030] In this embodiment, the multiple sheets forming the covering member 50 are arranged on the core material 10 so that their end faces face each other, as shown in Fig. 4. This prevents gaps from being generated between the multiple sheets on the outer surface of the core material 10. The thickness of the covering member 50 varies depending on the number of layers of the sheet-like elastic member. In other words, the thickness of the covering member 50 is adjusted by the number of layers of the sheet-like elastic member. That is, for example, as shown in Fig. 5, the thickness of the covering member 50 is adjusted by folding the ends of the sheet of the covering member 50 attached to both side surfaces of the core material 10 in the thickness direction at the ends in the plate width direction of the core material 10, and arranging the ends of the sheets so that they overlap each other.

[0031] Here, since the cross-sectional area of ​​the plasticized portion 11 of the core material 10 is smaller than that of the other portions than the plasticized portion 11, the lateral strain due to the axial compressive load is larger than that of the other portions than the plasticized portion 11. Therefore, in this embodiment, the thickness of the covering member 50 at the portion corresponding to the plasticized portion 11 is greater than the thickness of the portion other than the portion corresponding to the plasticized portion 11. That is, the thickness of the covering member 50 provided at the plasticized portion 11 is greater than the thickness of the covering member 50 provided at least at the wide portion 12. This makes it possible to optimize the amount of covering member 50 provided at each portion of the core material 10. That is, it is possible to prevent the covering member 50 from being provided more than necessary while making the covering member 50 thick enough for the amount of deformation of the core material 10. Furthermore, it is possible to increase the binding force of the core material 10 at the wide portion 12. The thickness of the covering member 50 in each of the plasticized portion 11 and the wide portion 12 is preferably adjusted in accordance with the difference in the amount of cross-sectional expansion based on, for example, Poisson's ratio.

[0032] In each of the plasticized portion 11 and the wide portion 12, the thickness of the covering member 50 is constant along the longitudinal direction of the core material 10. Furthermore, the thickness of the covering member 50 in the width-changing portion 13 may change stepwise along the longitudinal direction, for example, between the thickness of the covering member 50 in the plasticized portion 11 and the thickness of the covering member 50 in the wide portion 12. Alternatively, a boundary may be provided at any position in the longitudinal direction of the width-changing portion 13 between a portion having the same thickness as the covering member 50 in the plasticized portion 11 and a portion having the same thickness as the covering member 50 in the wide portion 12.

[0033] As described above, according to the buckling restrained brace 100 of this embodiment, the space between the restraining member 30 and the core material 10 is filled with the filler material 40. This makes it easier to keep the distance between the core material 10 and the filler material 40 constant along the longitudinal direction of the core material 10, compared to when the core material 10 is restrained by, for example, a square steel pipe or the like. In addition, the covering member 50 is in close contact with the surface of the core material 10 in the range in which the filler 40 is present in the longitudinal direction of the core material 10. As a result, the covering member 50 is interposed between the core material 10 and the filler 40. This makes it possible to prevent the core material 10 and the filler 40 from coming into direct contact with each other. Therefore, when the core material 10 deforms due to the application of a load, interference between the core material 10 and the filler 40, or the filler 40 following the deformation of the core material 10, can be prevented, and deformation of the filler 40 can be prevented.

[0034] Here, if there is a location where the distance between the plasticized portion 11 and the filling material 40 is partially large, when an axial compressive load is input to the core material 10, that location may be significantly deformed (buckled). Therefore, the thickness of the covering member 50 at the portion corresponding to the plasticized portion 11 is constant in the longitudinal direction of the core material 10. This makes it possible to make the distance between the plasticized portion 11 of the core material 10 and the filling material 40 constant along the longitudinal direction. Therefore, when an axial compressive load is input to the core material 10, it is possible to prevent significant deformation (buckling) in the portions of the core material 10 where the distance between the plasticized portion 11 and the filling material 40 is partially large. Therefore, it is possible to prevent extremely large strain from occurring locally in the plasticized portion 11 of the core material 10, and to uniform the longitudinal strain distribution in the core material 10. In other words, it is possible to generate strain evenly along the longitudinal direction of the core material 10. In addition, it is possible to uniformly apply the load to the plasticized portion 11 of the core material 10 in the longitudinal direction. Therefore, it is possible for the core material 10 to fully exert its axial strength against the axial compressive load. This improves the fatigue properties of the core material 10, making it easier to prevent breakage due to repeated compressive and tensile loads during an earthquake.

[0035] Here, since the cross-sectional area of ​​the plasticized portion 11 of the core material 10 is smaller than that of the other portions than the plasticized portion 11, the lateral strain due to the axial compressive load is larger than that of the other portions than the plasticized portion 11. Therefore, the thickness of the covering member 50 at the portion corresponding to the plasticized portion 11 is greater than the thickness of the portion other than the portion corresponding to the plasticized portion 11. This allows the covering member 50 to have a sufficient thickness when the plasticized portion 11 is deformed by an axial compressive load. This prevents the plasticized portion 11 after deformation from interfering with the filler 40. Furthermore, by reducing the thickness of the covering member 50 at the portion other than the portion corresponding to the plasticized portion 11, the cost of the covering member 50 can be reduced. Furthermore, the binding force of the core material 10 can be increased in the wide portion 12.

[0036] Here, in the longitudinal direction of the core material 10, a distribution in thickness or diameter may occur within the intersection. Therefore, the covering member 50 is an elastic member. As a result, the elastic member deforms appropriately according to the distribution of the thickness and diameter of the core material 10, and the separation distance between the plasticized portion 11 of the core material 10 and the filling material 40 can be made constant along the longitudinal direction while preventing the occurrence of gaps between the core material 10 and the covering member 50. Therefore, the occurrence of the gaps in the core material 10 can prevent extremely large strain from occurring in those areas.

[0037] Furthermore, the thickness of the covering member 50 varies depending on the number of layers of the elastic member. In other words, the thickness of the covering member 50 is adjusted by the number of layers of the elastic member. Therefore, the thickness of the covering member 50 can be easily adjusted.

[0038] Moreover, the elastic member is a plurality of sheets. In this way, the covering member 50 is provided by attaching the sheet-like elastic member to the core material 10. At this time, the plurality of sheets are arranged on the core material 10 so that their end faces face each other. This makes it possible to prevent gaps from being generated between the plurality of sheets. Therefore, it is possible to prevent extremely large distortion from being generated in the core material 10 in the portion where the gap is generated.

[0039] Moreover, the plasticized portion 11 includes a protruding portion 11p that protrudes toward the covering member 50. This allows the protruding portion 11p to be disposed so as to bite into the filler 40. This makes it possible to prevent the core material 10 and the filler 40 from being misaligned in the longitudinal direction of the core material 10.

[0040] Furthermore, the protruding portion 11p is exposed from the covering member 50, and at least its tip 11t is covered by the filler 40. This allows only the protruding portion 11p in the core material 10 to be in direct contact with the filler 40. This further prevents the core material 10 and the filler 40 from being misaligned in the longitudinal direction of the core material 10.

[0041] Moreover, the width of the protrusion 11p increases from the tip 11t toward the base 11r of the protrusion 11p. This allows the base 11r of the protrusion 11p, where stress is likely to concentrate, to be made wider relative to the tip 11t. Thus, stress is dispersed at the base 11r of the protrusion 11p, making it possible to form a shape that is less susceptible to cracking. This makes it possible to suppress the occurrence of cracks originating from the base 11r of the protrusion 11p, suppress breakage of the core material 10 caused by such cracks, and improve the fatigue properties of the core material 10 against repeated earthquakes.

[0042] Second embodiment Next, a buckling restrained brace 100 according to a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted, with only the differences being described. FIG. 6 is a cross-sectional view perpendicular to the longitudinal direction of the buckling restraint brace 100, and is a cross-sectional view of a portion corresponding to the plasticized portion 11 of the core material 10. In the second embodiment, the ratio of the thickness of the covering member 50 in the width direction of the core material 10 to the thickness in the thickness direction of the core material 10 is the same as the ratio of the width of the core material 10 to the thickness of the core material 10. That is, dw: thickness of the covering member 50 in the plate width direction of the core material 10 dt: thickness of the covering member 50 in the thickness direction of the core material 10 w: width of core material 10 t: thickness of core material 10 When dw / dt=w / t This allows the thickness of the covering member 50 to be made sufficient to withstand the amount of deformation that occurs when the core material 10 is deformed so as to expand due to lateral strain.

[0043] When an axial compressive load is input to core material 10 and the length of core material 10 shortens due to longitudinal strain, the cross-sectional area of ​​core material 10 increases due to lateral strain. If core material 10 is plate-shaped, the increase in the dimension of core material 10 in the plate width direction and the increase in the dimension of core material 10 in the plate thickness direction are proportional to the ratio of the plate width to the plate thickness. Therefore, according to the buckling restrained brace 100 of the second embodiment, the ratio of the thickness of the covering member 50 in the width direction of the core material 10 to the thickness of the core material 10 in the thickness direction is the same as the ratio of the width of the core material 10 to the thickness of the core material 10. This makes it possible to make the ratio of the thickness of the covering member 50 in the width direction of the core material 10 to the thickness direction of the core material 10 the same as the ratio of the increase in the dimension of the core material 10 in the width direction to the increase in the dimension of the core material 10 in the thickness direction when an axial compressive load is input to the core material 10. Therefore, the rate of deformation of the covering member 50 when the core material 10 is deformed by an axial compressive load can be made the same in the thickness direction and the width direction. Therefore, it is possible to suppress the occurrence of a difference in the state of the covering member 50 in the thickness direction and the width direction of the core material 10.

[0044] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the core material 10 has been described as being a flat plate, this is not limiting. That is, for example, the core material 10 may be cylindrical. That is, the cross section of the core material 10 may be circular or elliptical. In addition, although the stiffening member 20 has been described as being provided in the wide portion 12 of the core material 10, this is not limited thereto. That is, a member equivalent to the stiffening member 20 may be provided in the width changing portion 13 and the plasticized portion 11. In this way, the core material 10 may have a cross-shaped cross section along the longitudinal direction. Furthermore, the protrusions 11p may be formed separately from the plasticized portion 11 and attached by welding, etc. In this case, the protrusions 11p may be provided on the side surfaces of the plasticized portion 11 in the plate thickness direction. Also, although the covering member 50 has been described as a sheet-like elastic member, it is not limited to this. That is, the covering member 50 may be provided by coating or spraying a liquid member on the plasticized portion 11 and the wide portion 12 of the core material 10, on the premise that the thickness can be made constant along the longitudinal direction.

[0045] In addition, within the scope of the invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0046] 10 Core material 11 Plasticization part 11p protrusion 11r Base 11t tip 12 Wide section 13 Width change section 20 Reinforcement member 30 Restraining member 40 Filler 50 Covering material 100 Buckling Restraint Brace

Claims

1. A long core material; A coating member that coats a surface of the core material; A cylindrical restraining member that houses the core material with both ends protruding; A filler material is filled between the restraining member and the core material; A buckling restraint brace comprising: The core material includes a plasticized portion having a cross-sectional area smaller than both ends, The covering member is in close contact with the surface of the core material in a range in which the filler is present in the longitudinal direction of the core material, and a thickness of a portion corresponding to the plasticized portion is constant in the longitudinal direction of the core material. A buckling restrained brace characterized by:

2. The core material is plate-shaped, The ratio of the thickness of the covering member in the plate width direction of the core material to the thickness of the core material in the plate thickness direction of the core material is The ratio is the same as the ratio of the width of the core material to the thickness of the core material.

2. The buckling restrained brace of claim 1.

3. The thickness of the covering member at a portion corresponding to the plasticized portion is greater than the thickness of a portion other than the portion corresponding to the plasticized portion.

2. The buckling restrained brace of claim 1.

4. The covering member is an elastic member.

2. The buckling restrained brace of claim 1.

5. The thickness of the covering member varies depending on the number of layers of the elastic member.

5. The buckling restrained brace of claim 4.

6. the elastic member is a plurality of sheets; The plurality of sheets are disposed on the core material such that their end faces face each other.

5. The buckling restrained brace of claim 4.

7. The plasticized portion includes a protrusion protruding toward the covering member.

2. The buckling restrained brace of claim 1.

8. The protrusion is exposed from the covering member, and at least a tip thereof is covered with the filling material.

8. The buckling restrained brace of claim 7.

9. The width of the protrusion increases from the tip to the base of the protrusion.

9. The buckling restrained brace of claim 8.

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