Buckling restraint brace

Abstract

To provide a buckling restraint brace fitted with a wooden restraining material high in biting resistance.SOLUTION: A buckling restraint brace 100 comprises: a steel plate-like core material 10; and a wooden restraining body 20 formed by a pair of wooden restraining materials 30 and disposed to face the two wide surfaces 10a of at least the core material 10. Each of the restraining materials 30 is provided with a first restraining material 33 relatively high in biting strength and a second restraining material 34 relatively low in biting strength. One wide surface 31 of the first restraining material 33 is in contact with the wide surface 10a of the core material 10, and the wide surface 31 of the second restraining materials 34 is in contact with the other wide surface 31 of the first restraining material 33.SELECTED DRAWING: Figure 3B

Description

[Technical Field]

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

[0002] Buckling-restrained braces, which have been designed to prevent buckling, have traditionally been used as braces to form building frames (column-beam frames, roof frames, etc.). Buckling-restrained braces come in a variety of stiffening configurations, including a steel core reinforced only with steel plates, a steel core reinforced with reinforced concrete (RC), and a steel core covered with steel and mortar.

[0003] Recently, efforts have been made to improve the fire resistance and earthquake resistance of wooden buildings (such as wooden houses, wooden warehouses, and wooden stadiums). Wooden buildings inherently have advantages such as a high degree of freedom in floor plan and design, the soothing effect of natural wood, the humidity-regulating properties of wood, and generally lower construction costs compared to steel-framed or reinforced concrete structures, depending on the building application (e.g., residential). However, the improved fire resistance and earthquake resistance are one factor that has led to increased attention being paid to wooden buildings, including wooden houses. When the above-described conventional buckling restrained braces are incorporated into the framework of such wooden buildings, wooden columns and beams are mixed with buckling restrained braces with metal or concrete stiffeners, which inevitably results in an unbalanced appearance.

[0004] One possible solution is to cover the entire buckling restrained brace with a wooden or paper panel, making the metal or concrete stiffener invisible from the outside. However, this requires a great deal of work, which raises concerns about increased construction costs. Furthermore, conventional buckling restrained braces tend to be heavy because they make extensive use of metal, concrete, mortar, etc., and installing heavy buckling restrained braces inside the lightweight wooden beams and columns that make up a wooden building is structurally unbalanced.

[0005] Patent Document 1 proposes a buckling restrained brace suitable for use within the framework of wooden buildings such as wooden houses. Specifically, this is a buckling restrained brace that has a core material and a pair of restraining members arranged along both sides of the core material, where the core material is made of steel and the pair of restraining members are made of wood, and the restraining members are made of laminated lumber, with the lamina stacked parallel to the core material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4901491 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the buckling restrained brace described in Patent Document 1, the strength of the buckling restrained brace against global buckling can be improved by using a pair of restraining members made of wood.

[0008] During an earthquake, a buckling-restrained brace has wooden restraining bodies that stiffen the core material to prevent it from buckling, but if the core material buckles in a higher-order buckling mode along its weak axis, it will sink into the wooden restraining material, causing the restraining material to deform. If the restraining material has low compressive strength (or compressive rigidity), compressive deformation will occur early, increasing the gap between the core material buckling in a higher-order buckling mode and the restraining material that has become compressively deformed. This will generate a larger stiffening force that acts on the restraining material, potentially causing it to break. The buckling-restrained brace described in Patent Document 1 does not disclose any solution for suppressing compressive deformation of the restraining material when the core material buckles in a higher-order buckling mode.

[0009] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a buckling restrained brace in which wooden restraining members have high compressive strength. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the buckling restrained brace according to the present invention is as follows: A steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members arranged so as to face at least two wide surfaces of the core material; The restraining material includes a first restraining material having a relatively high embedment strength and a second restraining material having a relatively low embedment strength, The invention is characterized in that one wide surface of the first restraint member abuts against the wide surface of the core material, and the other wide surface of the first restraint member abuts against the wide surface of the second restraint member.

[0011] According to this aspect, the pair of wooden restraining members that form the wooden restraint include a first restraining member with a relatively high compressive strength (or compressive rigidity) and a second restraining member with a relatively low compressive strength. One wide surface of the first restraining member abuts the wide surface of the core member, and the wide surface of the second restraining member abuts the other wide surface of the first restraining member. This suppresses the compressive deformation (deformation) of the core member, which is buckling in a higher-order buckling mode, into the first restraining member, resulting in a buckling-restrained brace with a wooden restraint that has high compressive strength. Furthermore, because the core member is surrounded by the wooden restraining members, the buckling-restrained brace has excellent exterior design, so even when applied to the frame of a wooden building, it does not present an appearance that is out of sync with the frame components.

[0012] In this embodiment, for example, the wide surfaces of both of the pair of first constraining members abut against the entire pair of wide surfaces of the core material, constraining the core material. When both the first constraining member and the second constraining member are formed of lamina, the pair of wide surfaces of the core material are directly constrained by the first constraining member consisting of a pair (two) laminas, and one lamina or a stack of multiple laminas is stacked on each first constraining member to form a pair of constraining members. Here, the first constraining member and the second constraining member are formed by being bonded to each other via adhesive, fastened to each other with fasteners such as wood screws, or joined by both adhesive and attachment, for example.

[0013] Here, examples of wood species (tree species) with different embedment strength include domestic cypress, larch, and domestic cedar. For example, since cypress has a higher embedment strength than cedar, a restraining material can be formed by combining a first restraining material made of cypress and a second restraining material made of cedar.

[0014] Another aspect of the buckling restrained brace according to the present invention is: A separate first restraining member is disposed at the outermost edge of the restraining member, and the wide surface of the separate first restraining member abuts against the wide surface of the second restraining member.

[0015] According to this aspect, a separate first restraining member is disposed on the outermost edge of the restraining member, and the wide surface of the separate first restraining member abuts the wide surface of the second restraining member, thereby increasing the bending strength (or bending rigidity, bending strength) of the wooden restraint. Therefore, in this aspect, first restraining members are disposed on both the core side (inside) and the outermost edge (outside) of the restraint member, and the second restraining member is disposed between them, resulting in a buckling-restrained brace with a wooden restraint member that has both high compressive strength and bending strength.

[0016] A more specific form is one in which the first restraint material and the second restraint material are both formed from laminas, and a second restraint material made of one or more laminas is arranged between the first restraint material made up of a pair of laminas, and the restraint materials are joined to each other.

[0017] Another aspect of the buckling restrained brace according to the present invention is: A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; The restraining material includes a first restraining material having a relatively high embedment strength and a second restraining material having a relatively low embedment strength, The wide surfaces of the multiple first restraining materials abut against each other, the narrow surfaces of the multiple first restraining materials abut against at least a portion of the wide surface of the core material, and the wide surface of the second restraining material abuts against the wide surface of the first restraining material.

[0018] According to this aspect, the wide surfaces of the multiple first restraint members abut against each other, the narrow surfaces of the multiple first restraint members abut against at least a portion of the wide surface of the core material, and the wide surface of the second restraint member abuts against the wide surface of the first restraint member.This suppresses the core material, which is buckling in a higher-order buckling mode, from sinking (deforming) into the first restraint member, and allows the formation of a buckling-restrained brace with a wooden restraint body that has high sink-resistance.

[0019] In this embodiment, the narrow surfaces of the first constraining members abut against and constrain the wide surfaces of the core material, so that the strong axis direction of the first constraining members is the direction that constrains the wide surfaces of the core material. This increases the constraining effect of the first constraining members compared to a configuration in which the wide surfaces of the first constraining members abut against the wide surfaces of the core material, i.e., a configuration in which the weak axis direction of the first constraining members is the direction that constrains the wide surfaces of the core material. Therefore, even if the narrow surfaces of the multiple first constraining members do not constrain the entire wide surface of the core material, it is possible to effectively suppress the core material from sinking into the first constraining member (deformation). Therefore, the configuration may be such that "the narrow surfaces of the multiple first constraining members abut against at least a portion of the wide surface of the core material." Here, "contacting at least a portion of the wide surface of the core material" includes a configuration in which the narrow surfaces of the multiple first restraint materials contact, for example, a range of approximately 30% to 70% of the central area of ​​the wide surface of the core material, as well as a configuration in which they contact the entire wide surface of the core material.

[0020] For example, as mentioned above, when domestically produced cypress and cedar are used as the first and second restraining materials, respectively, the material cost of cypress is higher than that of cedar. Therefore, by making the first restraining material abut against part of the wide surface of the core material, the material cost of the entire restraining material (and wooden restraint body) can be reduced as much as possible.

[0021] In this embodiment, the first restraining member, which has high compressive strength, is located at the outermost edge of the region where the first restraining member is located, which increases the bending strength (bending rigidity, bending strength) of the wooden restraint. Therefore, in this embodiment, the first restraining member is arranged in a position extending from the core side (inside) to the outermost edge (outside), and the second restraining member is arranged to the side of the first restraining member, resulting in a buckling-restrained brace with a wooden restraint member that has both high compressive strength and bending strength.

[0022] In another aspect of the buckling restrained brace according to the present invention, the core material has a narrow portion at a center side in a longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, a reinforcing rib orthogonal to the wide surface of the end of the core material in the longitudinal direction is joined to the wide surface, forming a cross-shaped cross section; The pair of restraining members are characterized in that a slit is provided at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib.

[0023] According to this aspect, the core material has a narrow portion at the center in the longitudinal direction where the wide surface is relatively narrow, and a wide portion at the end in the longitudinal direction where the wide surface is relatively wide, so that the narrow portion at the center can be made a region that is easily plasticized, and further, the plasticized region can be limited to the narrow portion at the center. Furthermore, since the boundary region between the wide portion and the narrow portion is a transition region where the planar area and cross-sectional area of ​​the core material change, the transition region can absorb the additional bending moment acting on the core material.

[0024] Here, the additional bending moment (or simply, additional bending) refers to the bending moment that occurs at the end of the buckling-restrained brace due to deformation of the structural plane during, for example, a major earthquake. In this manner, in this mode, the additional bending moment that occurs at the end of the buckling-restrained brace (core member) can be effectively absorbed by the boundary region between the wide and narrow sections of the core member.

[0025] Furthermore, by joining reinforcing ribs perpendicular to the wide faces of the core material to the longitudinal ends of the core material, giving the core material a cross-shaped cross section, when the buckling restrained brace is attached to a gusset plate so that the wide faces of the core material are arranged parallel to the structural face of the building, the core material has reinforcing ribs perpendicular to the wide faces parallel to the structural face, which increases the rigidity of the end of the core material in the direction outward from the structural face.In the gusset plate of the structural face to which this cross-sectional core material is attached, fin stiffeners are attached to the gusset plate, and the core material of the buckling restrained brace and gusset plate, and the reinforcing ribs and fin stiffeners are each joined via splice plates with high-tension bolts or the like.

[0026] Furthermore, the restraining material is provided with slits at positions corresponding to the reinforcing ribs so as not to interfere with the reinforcing ribs, and the reinforcing ribs are accommodated in the slits with a gap between them. This prevents the reinforcing ribs from coming into contact with and being pressed against the restraining material when the frame and buckling restraint brace are deformed, thereby suppressing or preventing damage to the restraining material.

[0027] In another aspect of the buckling restrained brace according to the present invention, The wooden restraint body is characterized by further having a pair of wooden side panels that connect the corresponding ends of the pair of restraint members.

[0028] According to this aspect, the wooden restraint further includes a pair of wooden side panels that connect the corresponding ends of the pair of restraining members, thereby enabling the core member to be enclosed by the wooden restraint with a strong closed structure. The wooden restraint and the side panels can be connected by adhesive, nails, screws, bolts, or a combination thereof.

[0029] Another aspect of the buckling restrained brace according to the present invention is: A spacer is disposed in the gap between the narrow portion and the side plate.

[0030] According to this aspect, the spacer is disposed in the gap between the narrow portion and the side plate, thereby preventing the core material from shifting toward the side plate. [Effects of the Invention]

[0031] As can be understood from the above description, the buckling restrained brace of the present invention can provide a buckling restrained brace in which the wooden restraining member has high compressive strength. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a perspective view illustrating an example of a core material that forms a buckling restrained brace according to an embodiment. [Figure 2] FIG. 1 is a perspective view of an example of a buckling restrained brace according to embodiments. [Figure 3A] 3 is a view taken along the arrows IIIa-IIIa in FIG. 2, showing a longitudinal cross-sectional view of an end portion of an example of a buckling restrained brace according to an embodiment. FIG. [Figure 3B] FIG. 3 is a view taken along the line IIIb-IIIb in FIG. 2, showing a longitudinal cross-sectional view of the center of an example of a buckling restrained brace according to an embodiment. [Figure 4A] FIG. 3B is a diagram corresponding to FIG. 3A and is a longitudinal cross-sectional view of the end portion of another example of a buckling restrained brace according to an embodiment. [Figure 4B] FIG. 3C is a diagram corresponding to FIG. 3B and is a longitudinal cross-sectional view of the center portion of another example of a buckling restrained brace according to an embodiment. [Figure 5A] FIG. 3B is a diagram corresponding to FIG. 3A and is a longitudinal cross-sectional view of the end portion of yet another example of a buckling restrained brace according to an embodiment. [Figure 5B] FIG. 3C is a diagram corresponding to FIG. 3B and is a longitudinal cross-sectional view of the center portion of yet another example of a buckling restrained brace according to an embodiment. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. 2, taken at a position midway through the thickness of the restraint material. [Figure 7] 10 is a schematic diagram illustrating a state in which the first constraining member resists deformation of the core member in a higher-order buckling mode by its embedment strength. FIG. [Figure 8] FIG. 1 is a diagram showing a state in which a buckling restraint brace according to an embodiment is incorporated into the frame of a wooden building or the like. [Figure 9] 1 is a diagram illustrating the deformation of the frame during a major earthquake and the additional bending moment at the buckling-restrained brace joint due to the deformation of the frame. [Figure 10] FIG. 10 is a diagram showing the overall buckling line of the buckling restraint brace. [Figure 11] 10A and 10B are diagrams illustrating the buckling and stiffening force of the higher-order buckling mode of the core material. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, a buckling restrained brace according to an embodiment will be described with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components will be designated by the same reference numerals, and redundant description may be omitted.

[0034] [Buckling restrained brace according to the embodiment] First, an example of a buckling-restrained brace according to an embodiment will be described with reference to FIGS. 1 to 7. Here, FIG. 1 is a perspective view showing an example of a core material forming a buckling-restrained brace according to an embodiment, and FIG. 2 is a perspective view of an example of a buckling-restrained brace according to an embodiment. Also, FIG. 3A is a view taken along arrows IIIa-IIIa in FIG. 2 and is a longitudinal cross-sectional view of an end portion of an example of a buckling-restrained brace according to an embodiment. FIG. 3B is a view taken along arrows IIIb-IIIb in FIG. 2 and is a longitudinal cross-sectional view of the center portion of an example of a buckling-restrained brace according to an embodiment. Also, FIGS. 4A and 5A correspond to FIG. 3A and are longitudinal cross-sectional views of the end portion of another example of a buckling-restrained brace according to an embodiment. FIGS. 4B and 5B correspond to FIG. 3B and are longitudinal cross-sectional views of the center portion of another example of a buckling-restrained brace according to an embodiment. Furthermore, Figure 6 is a view taken along the arrows VI-VI in Figure 2, and is a cross-sectional view cut at a position midway through the thickness of the restraint material, and Figure 7 is a schematic diagram explaining the state in which the first restraint material resists the deformation of the core material in a higher-order buckling mode with its embedment strength.

[0035] As shown in Figure 1, the core material 10 is formed from a long, slender, plate-shaped flat steel, and has a narrow width portion 11 at the center of its longitudinal direction, where the width of the wide surface 10a is relatively narrow, and a wide width portion 12 at the end of its longitudinal direction, where the width of the wide surface 10a is relatively wide.

[0036] More specifically, the wide portion 12 has a first wide portion 12A at the end and a second wide portion 12B that is relatively narrower than the first wide portion 12A. The width is tapered from the first wide portion 12A to the second wide portion 12B. Here, the wide portion 12 does not have to have two wide portions with different widths, and may instead have only one wide portion (wide portion 12A).

[0037] A reinforcing rib 14 perpendicular to the wide surface 10a is welded to the center of the wide surface 10a from the first wide portion 12A to the second wide portion 12B, giving the wide portion 12 a cross-shaped cross section.

[0038] The core material 10 has a narrow width portion 11 at the center of its longitudinal direction and a wide width portion 12 at the end of its longitudinal direction, so that the narrow width portion 11 at the center can be made into a region that is easily plasticized (plasticization region).

[0039] In the illustrated example, the reinforcing ribs 14 are attached to the wide portion 12, which further increases the rigidity of the wide portion 12, making the narrow portion 11 more susceptible to plastic deformation. The additional bending moment acting on the core material 10 is effectively absorbed in the narrow portion 11, which is the plastic deformation region.

[0040] In addition, the wide portion 12 and the reinforcing rib 14 are each provided with bolt holes 12a, 14a for bolting via a splice plate to a gusset plate provided on the structural surface or a fin stiffener (see Figure 8) attached to the gusset plate, as described below.

[0041] When the buckling restraint brace 100 is attached to the gusset plate so that the wide surface 10a of the core material 10 is arranged parallel to the structural face of the building, the core material 10 has reinforcing ribs 14 that are perpendicular to the wide surface 10a that is parallel to the structural face, thereby increasing the rigidity of the end of the core material 10 in the direction outside the structural face.

[0042] The core material 10 is preferably formed from a steel material with a low yield point, such as SN material (rolled steel for building structures) or LYP material (extremely low yield point steel), and the yielding of the core material 10 improves earthquake energy absorption.

[0043] As shown in Figure 2, a pair of wooden restraint members 30 are arranged on either side of a pair of wide surfaces 10a of the core material 10, and a pair of wooden side panels 40 are connected to the ends of the pair of restraint members 30 to form a wooden restraint body 20, and a buckling restraint brace 100 is formed in which the core material 10 is surrounded by the wooden restraint body 20.

[0044] The restraining members 30 and the side panels 40 are connected by one or more of adhesive, nails, screws, and bolts. The wooden restraining body may also be formed by only a pair of restraining members (a configuration without side panels), in which case the pair of restraining members are connected by adhesive, nails, screws, etc.

[0045] A slit 35 is provided at the longitudinal end of the restraint material 30, and a portion of the reinforcing rib 14 joined to the end of the core material 10 is loosely fitted into the slit 35, thereby preventing interference between the restraint material 30 and the reinforcing rib 14.

[0046] 3A and 3B, the restraining member 30 is a laminated wood formed by stacking and bonding multiple laminas together. More specifically, the restraining member 30 includes a first restraining member 33 with relatively high compressive strength and a second restraining member 34 with relatively low compressive strength. One wide surface 31 of the first restraining member 33 abuts against the entire wide surface 10a of the core material 10, and the other wide surface 31 of the first restraining member 33 abuts against the wide surface 31 of the second restraining member 34.

[0047] The restraint material 30 in the illustrated example is a laminate of one layer of a first restraint material 33 and three layers of a second restraint material 34, but it may have a number of layers other than that shown in the illustration, for example, it may be a laminate of one layer of a first restraint material 33 and two or four or more layers of a second restraint material 34.

[0048] The wood species suitable for the lamina, in descending order of compressive strength, include beimatsu (Japanese larch), Dahurica larch, hinoki (Japanese cypress), larch, cedar, and Scots pine (beimatsu, Dahurica larch > hinoki, larch > cedar, Scots pine). Therefore, two species can be selected from these and used as the first restraining member 33 and the second restraining member 34, respectively, to form the restraining member 30.

[0049] As shown in Figure 7, when core material 10 buckles in a higher-order buckling mode, a stiffening force P (pressure) acts from the peak of the deformed core material 10 to the wide surface 31 of restraining material 30. However, because first restraining material 33, which has high compressive strength, faces wide surface 10a of core material 10, the compressive strength of restraining material 30 against compressive deformation of core material 10 into restraining material 30 can be increased, and compressive deformation of restraining material 30 can be suppressed. This makes it possible to suppress damage to restraining material 30 due to compressive deformation, and improves the durability of buckling-restrained brace 100.

[0050] Here, among the above-mentioned tree species, by using cypress and cedar, which are native to Japan, it is possible to meet the needs for using native materials, and since these native materials have excellent external design properties, the external design properties of the buckling restraint brace 100 can be further improved.

[0051] Although not shown in the figure, the core material 10 may have protrusions on both wide surfaces 10a of the narrow portion 11, and grooves at positions corresponding to the protrusions on the wide surfaces of the restraining material 30, so that the protrusions fit into both grooves, thereby preventing the core material 10 from slipping relative to the restraining material 30.

[0052] 3A and 6, a gap G1 of a predetermined width is provided between the slit 35 of the restraint member 30 and the reinforcing rib 14. When the structural surface to which the buckling restrained brace 100 is attached undergoes significant deformation in the strong axis direction or the weak axis direction, this gap G1 absorbs the deformation of the core member 10 (and the reinforcing rib 14), preventing the reinforcing rib 14 from acting on the restraint member 30 and damaging the wooden restraint body 20.

[0053] 3A and 6, a gap G2 is provided in the end region of the core material 10 between the wide portion 12 and the side panel 40 and between the wide portion 12 and the side panel 40 and the restraining member 30. This gap G2, like gap G1, absorbs deformation of the core material 10 and prevents the wide portion 12 of the core material 10 from acting on the side panel 40 or the restraining member 30 and damaging the wooden restraining body 20.

[0054] On the other hand, as shown in FIG. 3B , the central region of the core material 10 is restrained by the wide surface 10a of the core material 10 abutting against the wide surface 31 of the first restraining member 33 of the restraining member 30. Meanwhile, a spacer 50 is interposed between the narrow surface 10b of the core material 10 and the side panel 40 to prevent the core material 10 from shifting toward the side panel 40. Here, the spacer 50 may be made of steel or wood. If wood, it is preferably made of a wood species with high embedding strength, similar to the first restraining member 33. The spacer 50 may also be fixed to one of the restraining members 30 with nails, screws, or the like. Furthermore, although not shown, the pair of restraining members 30 and the spacer 50 may be joined to each other by a plurality of bolts passing through these members.

[0055] On the other hand, the wooden restraint body 20A that forms the buckling restraint brace 100A shown in Figures 4A and 4B differs from the restraint material 30 of the wooden restraint body 20 in that a pair of restraint materials 30A has first restraint materials 33 with relatively high embedment strength on the core side and outermost edge, and has multiple (two in the illustrated example) second restraint materials 34 between them.

[0056] The first restraining members 33, which have high compressive strength, are also provided on the outermost edges of the restraining members 30A, thereby increasing the bending strength of the wooden restraining body 20A. Therefore, the first restraining members 33 are provided on both the core side and the outermost edges of the restraining member 30A, and the second restraining members 34 are provided between them, resulting in a buckling-restrained brace 100A equipped with wooden restraining members 20A that have both high compressive strength and bending strength.

[0057] On the other hand, the wooden restraint body 20B that forms the buckling restraint brace 100B shown in Figures 5A and 5B differs from the restraint member 30 of the wooden restraint body 20 and the restraint member 30A of the wooden restraint body 20A in that, in each of the pair of restraint members 30B, the wide surfaces 31 of multiple (two in the illustrated example) first restraint members 33 abut against each other, the narrow surfaces 32 of the multiple first restraint members 33 abut against portions of the wide surface 10a of the core material 10, and the wide surface 31 of the second restraint member 34 abuts against the wide surface 31 of the first restraint member.

[0058] Since the narrow surface 32 of the first restraining member 33 abuts against the wide surface 10a of the core material 10 to restrain the core material 10, the strong axis direction of the first restraining member 33 is in the direction that restrains the wide surface 10a of the core material 10. Therefore, the restraining effect of the first restraining member 33 is greater than in the case of restraining members 30, 30A in which the wide surface 31 of the first restraining member 33 abuts against the wide surface 10a of the core material 10, i.e., the weak axis direction of the first restraining member 33 is in the direction that restrains the wide surface 10a of the core material 10.

[0059] Therefore, even if the narrow surfaces 32 of the multiple first restraining members 33 do not restrain the entire wide surface 10a of the core material 10, the core material 10 can be effectively prevented from sinking (deforming) into the first restraining members 33, making it unnecessary for multiple (two in the illustrated example) first restraining members 33 to abut the entire wide surface 10a of the core material 10, as in the illustrated example.

[0060] For example, in the illustrated example, the narrow faces 32 of the two first restraining members 33 abut against an area of ​​about 70% of the wide face 10a of the core material 10, but if necessary, there may be only one first restraining member 33 abutting against about 30% of the wide face 10a of the core material 10. Note that in the illustrated example, the four central lamina may be made up of first restraining members 33, and therefore the narrow faces 32 of the four first restraining members 33 may abut against the entire wide face 10a of the core material 10 to restrain the core material 10.

[0061] For example, as described above, when domestically produced cypress and cedar are used for the first restraining material 33 and the second restraining material 34, respectively, the material cost of cypress is higher than that of cedar. Therefore, it is preferable to form the first restraining material 33 in contact with a portion of the wide surface 10a of the core material 10, as in the illustrated example, since this reduces the material cost of the entire restraining material 30B (and wooden restraining body 20B) as much as possible.

[0062] [Framework incorporating buckling restraint braces] Next, an example of a building frame incorporating a buckling restrained brace 100 will be described with reference to Figures 8 and 9. Here, Figure 8 is a diagram showing a buckling restrained brace according to an embodiment incorporated into the frame of a wooden building or the like. Also, Figure 9 is a diagram explaining the deformation of the frame during a major earthquake and the additional bending moment at the buckling restrained brace joint resulting from the deformation of the frame. Note that the buckling restrained brace shown in the figure may be incorporated into the frame of a steel (S) building, a reinforced concrete (RC) building, or a steel reinforced concrete (SRC) building, in addition to the frame of a wooden building.

[0063] The frame S shown in Figure 8 is formed from wooden columns C and beams B that constitute a wooden building or the like. Gusset plates GP made of flat steel are attached to the two diagonally positioned corners. Fin stiffeners FS are welded to the surface of the gusset plates GP so that they are perpendicular to the surface. The fin stiffeners FS are joined to the gusset plates GP so that their center L3 intersects with the intersection O between the column center L1 of the column C and the beam center L2 of the beam B. The buckling restrained brace 100 is also arranged linearly passing through both diagonally positioned intersections O.

[0064] The gusset plate GP and the wide portion 12 of the core material 10 are joined by high tension bolts via a splice plate SP, and the fin stiffener FS and the reinforcing rib 14 are joined by high tension bolts via a splice plate SP.

[0065] As shown in Figure 9, when a large earthquake occurs, deformation of the structural plane can cause an additional bending moment, as shown in equation (1) below, to act on the buckling-restrained brace joint, assuming that the joint is rigid.

[0066]

number

[0067] According to the buckling-restrained brace 100, the wooden restraining body 20, which includes a pair of wooden restraining members 30, restrains the core member 10, thereby suppressing overall buckling of the buckling-restrained brace 100, and therefore the buckling-restrained brace 100 has the strength to withstand both overall buckling and higher-order buckling of the core member 10. This makes it possible to form a frame S with excellent earthquake resistance.

[0068] [Study of overall buckling] Next, we will explain the design method for preventing global buckling of buckling-restrained braces.

[0069] When designing a buckling-restrained brace, the following formula (2) must be satisfied to prevent global buckling of the buckling-restrained brace.

[0070]

number

[0071] Here, the bending moment acting on the center of the restraint member can be expressed by the following equation (3).

[0072]

number

[0073] The condition for preventing the overall buckling of the wooden restraint body is to satisfy the following equation (4).

[0074]

number

[0075] Equation (4) is shown in Figure 10 as the global bending stress curve for the buckling-restrained brace. In Figure 10, the upper side of the global bending stress curve is the safe zone, and the lower side is the dangerous zone. The design axial force of the wooden restraint body, the Euler load, the length of the general part of the core material, and the yield bending strength of the wooden restraint body are set so that they fall within the safe zone. Note that the global bending stress curve for the buckling-restrained brace shown in Figure 10 applies to both global buckling in the weak axis direction of the core material and global buckling in the strong axis direction.

[0076] In addition to examining the relationship between the yield bending strength of the wooden restraint body and the bending moment acting on it, it is also advisable to examine whether the short-term allowable bending strength of the wooden restraint body is greater than the bending moment acting when the core material yields (formula omitted).

[0077] [Study on the collapse of wooden restraints due to compression] Next, a method for examining the compressive failure of a wooden restraint body will be described with reference to Figure 11. In a buckling restrained brace 100 or the like, to prevent the wooden restraint body from failing due to the core material compressing into the wooden restraint body, it is verified that the following formula (5) is satisfied.

[0078]

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[0079] Here, in addition to examining the relationship between the compressive strength of the restraining material and the stiffening force acting on it, it is also advisable to examine the fact that the short-term allowable compressive strength of the restraining material will be greater than the stiffening force acting when the core material yields (formula omitted).

[0080] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0081] 10: Core material 10a: Wide surface 10b:Narrow side 11: Narrow section 12: Wide section 12A: First wide section (wide section) 12B: Second wide section (wide section) 12a: Bolt hole 14: Reinforcing rib 14a: Bolt hole 20, 20A, 20B: Wooden restraints 30,30A,30B:Restraint material 31: Wide surface 32: Narrow surface 33: 1st restraint material 34:Second restraint material 35: Slit 40: Side panel 50: Spacer 100, 100A, 100B: Buckling restraint brace G1, G2: Gap P: Stiffening force S: Frame (composition) C: Pillar B: Beam GP: Gusset plate FS: Fin stiffener SP: Splice plate

Claims

1. A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; The restraining material includes a first restraining material having a relatively high embedment strength and a second restraining material having a relatively low embedment strength, A buckling restraint brace characterized in that one wide surface of the first restraint member abuts the wide surface of the core material, and the other wide surface of the first restraint member abuts the wide surface of the second restraint member.

2. 2. The buckling restraint brace of claim 1, wherein a separate first restraint member is disposed at the outermost edge of the restraint member, and the wide surface of the separate first restraint member abuts the wide surface of the second restraint member.

3. A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; The restraining material includes a first restraining material having a relatively high embedment strength and a second restraining material having a relatively low embedment strength, A buckling restraint brace characterized in that the wide surfaces of multiple first restraint members abut against each other, the narrow surfaces of the multiple first restraint members abut against at least a portion of the wide surface of the core material, and the wide surface of the second restraint member abuts against the wide surface of the first restraint member.

4. the core material has a narrow portion at a center side in a longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, a reinforcing rib orthogonal to the wide surface of the end of the core material in the longitudinal direction is joined to the wide surface, forming a cross-shaped cross section; 4. The buckling restraint brace according to claim 1, wherein a slit is provided in the pair of restraint members at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib.

5. 5. The buckling restraint brace according to claim 4, wherein the wooden restraint body further comprises a pair of wooden side panels connecting corresponding ends of the pair of restraint members.

6. 6. The buckling restrained brace according to claim 5, wherein a spacer is disposed in a gap between the narrow portion and the side plate.

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