Buckling restrained brace

Abstract

To provide a buckling restrained brace capable of suppressing breakage of an end part side of a wooden restraining body for restraining a core material by stiffening force generated by development of a high-order buckling mode on an end part side of a steel core material.SOLUTION: A buckling restrained brace 100 has: a steel plate-like core material 10; and a wooden restraining body 20 formed of a pair of wooden restraining materials 30 disposed so as to face at least two wide surfaces 10a of the core material 10, wherein the core material 10 includes a narrow part 11 having a relatively narrow width of the wide surface 10a at its center side in its longitudinal direction, and includes a wide part 12 in which the wide surface 10a is relatively wide provided on the end part side in its longitudinal direction, the wide part 12 is provided with a first wide part 12A at the end part and a second wide part 12B which is relatively narrower than the first wide part 12A, and the narrow part 11 is smoothly narrowed from the end part which is a boundary P1 with the second wide part 12B to a central position O of the narrow part 11.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] Buckling-restrained braces with buckling prevention measures have been used as braces that form building frames (column-beam frames, roof frames, etc.). Buckling-restrained braces come in a variety of stiffening forms, including a form in which the periphery of a steel core is stiffened only with steel plates, a form in which the periphery of a steel core is stiffened with RC (Reinforced Concrete), and a form in which the periphery of a steel core is covered with steel and mortar.

[0003] Recently, efforts have been made to improve the fire resistance and earthquake resistance of wooden buildings (wooden houses, wooden warehouses, wooden stadiums, etc.). Wooden houses inherently have advantages such as a high degree of freedom in layout and design, the soothing effect of natural wood, the moisture-regulating effect of wood, and generally lower construction costs compared to steel-framed or reinforced concrete structures depending on the building purpose such as housing, but the above-mentioned improvement in fire resistance and earthquake resistance is one of the factors that has increased the attention of wooden buildings such as wooden houses. When the above-mentioned conventional buckling restraint brace is incorporated into the frame of such a wooden house, wooden columns and beams are mixed with buckling restraint braces with metal or concrete stiffeners, which inevitably results in an unbalanced appearance.

[0004] One possible solution is to cover the entire buckling restraint brace with a wooden or paper panel, making the metal or concrete stiffener invisible from the outside, but this requires a great deal of work and labor, which raises concerns about increased construction costs.In addition, conventional buckling restraint braces tend to be heavy because they use a lot of metal, concrete, mortar, etc., and it is structurally unbalanced to attach a heavy buckling restraint brace to the lightweight wooden beams and columns that make up a wooden house.

[0005] Here, Patent Document 1 proposes a buckling restrained brace suitable for use in the framework of wooden buildings such as wooden houses. Specifically, this is a buckling restrained brace having a core material and a pair of restraining members arranged along both sides of the core material, in which the core material is made of steel and the pair of restraining members are made of wood, and laminated lumber is used for the restraining members, with the laminated lumber having 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] Incidentally, one form of core material that forms a buckling restrained brace is one in which the center of the longitudinal direction has a narrow portion where the wide surface is relatively narrow, and the end portions of the longitudinal direction have wide portions where the wide surface is relatively wide, and the wide portions on the end sides are connected to gusset plates, brackets, etc. of the frame. By making the end sides wide in this way, the rigidity of the end portions of the core material becomes relatively high, and the end portions connected to the frame are prevented from yielding preemptively during an earthquake, and by plasticizing the narrow portion on the central side, a buckling restrained brace with excellent earthquake energy absorption properties is obtained.

[0009] However, because plasticization of the core material tends to begin near the boundary between the narrow section and the wide section (the cross-sectional change area), a higher-order buckling mode begins to develop at the end of the core material, generating a stiffening force that can easily cause cracks and other damage to the end of the wooden restraint body that restrains the core material.The buckling restrained brace described in Patent Document 1 does not disclose any means of solving this type of damage to the wooden restraint body that corresponds to the end of the core material.

[0010] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a buckling restraint brace that can prevent damage to the end side of a wooden restraint body that restrains a core material due to a stiffening force generated by the progression of a higher-order buckling mode at the end side of the core material. [Means for solving the problem]

[0011] In order to achieve the above object, one aspect of the buckling restraint brace according to the present invention is as follows: A steel plate-shaped core material, a wooden restraining body formed of a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; 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 has a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, the wide portion having a first wide portion at the end and a second wide portion relatively narrower than the first wide portion; The narrow width portion is characterized in that the width smoothly narrows from the end portion that is the boundary with the second wide width portion to the center position of the narrow width portion.

[0012] According to this embodiment, the wide portion on the end side of the core material has a first wide portion at the end and a second wide portion which is relatively narrower in width, and the narrow portion of the core material smoothly narrows in width from the end which is the boundary with the second wide portion to its center position.This allows the progression of higher-order buckling modes in the core material to begin from the center of the narrow portion, thereby suppressing the generation of stiffening forces on the end side of the core material and making it possible to suppress damage to the end side of the wooden restraint body caused by the stiffening forces.

[0013] In addition, since the core material has a narrow portion where the width is smoothly narrowed to the center, the additional bending moment acting on the core material can be effectively absorbed in the center region of the core material. Here, the additional bending moment (or simply, additional bending) refers to the bending moment that may act on the wooden restraint body due to the deformation of the frame and the buckling restrained brace when the frame and the buckling restrained brace are significantly deformed during a major earthquake, for example.

[0014] Here, "the width narrows smoothly" includes a form in which the end edges of the narrow portion are curved in a plan view so that the width gradually narrows, and a form in which the end edges of the narrow portion are tapered and then curved toward the center so that the width gradually narrows.

[0015] In this embodiment, a pair of wooden restraining members surrounds a steel core member. With this configuration, even if the buckling restrained brace of this embodiment is applied to the frame of a wooden building, there is no risk of it giving an out-of-match appearance to the frame components. Here, the restraining members may be made of solid wood or may be made of laminated wood in which laminas are laminated.

[0016] Another aspect of the buckling restraint brace according to the present invention is A steel plate-shaped core material, a wooden restraining body formed of a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; 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 has a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, the wide portion having a first wide portion at the end and a second wide portion relatively narrower than the first wide portion; The narrow width portion is characterized by having a width change region where the width smoothly narrows from the end portion which is the boundary with the second wide width portion, and a minimum width region of a certain section toward the center which is the narrowest.

[0017] According to this embodiment, the wide portion on the end side of the core material has a first wide portion on the end and a second wide portion which is relatively narrow, and the narrow portion of the core material has a width change region where the width smoothly narrows from the end which is the boundary with the second wide portion, and a minimum width region of a certain section on the central side which is the narrowest.Therefore, the development of higher-order buckling modes in the core material can be started from the central side of the narrow portion, thereby suppressing the generation of stiffening forces on the end side of the core material and making it possible to suppress damage to the end side of the wooden restraint body due to the stiffening forces.

[0018] Here, the width changing region includes a form in which the end edge is curved in a planar view and the width gradually narrows as it slides into the minimum width region, and a form in which the end edge is tapered and then curved and the width gradually narrows as it slides into the minimum width region.

[0019] Another aspect of the buckling restraint brace according to the present invention is A steel plate-shaped core material, a wooden restraining body formed of a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; The core material has a narrow width portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide width portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, The narrow width portion is characterized in that the width gradually narrows from a predetermined position on the end side to the center position of the narrow width portion.

[0020] According to the present embodiment, the narrow width portion has a constant width from the boundary with the wide width portion to a predetermined position, and the width smoothly narrows from the predetermined position to the center of the narrow width portion. This allows the progression of higher-order buckling modes in the core material to begin from the center of the narrow width portion, thereby suppressing the generation of stiffening forces on the end side of the core material and making it possible to suppress damage to the end side of the wooden restraint body due to the stiffening forces.

[0021] Another aspect of the buckling restraint brace according to the present invention is A steel plate-shaped core material, a wooden restraining body formed of a pair of wooden restraining members arranged so as to face at least two wide surfaces of the core material; The core material has a narrow width portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide width portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, The narrow width portion is characterized by having a width change region where the width smoothly narrows from a predetermined position on the end side, and a minimum width region of a certain section on the central side where the width is the narrowest.

[0022] According to this aspect, the narrow width portion has a constant width from the boundary with the wide width portion to a predetermined position, and is provided with a width changing region where the width smoothly narrows from the predetermined position, and a minimum width region of a certain section toward the center which is the narrowest.This allows the development of higher-order buckling modes in the core material to begin from the center of the narrow width portion, thereby suppressing the generation of stiffening forces on the end side of the core material and making it possible to suppress damage to the end side of the wooden restraint body due to the stiffening forces.

[0023] In another aspect of the buckling restrained brace according to the present invention, A reinforcing rib is joined to the wide surface at the end of the longitudinal direction of the core material so as to be perpendicular to the wide surface, forming a cross-shaped cross section; A pair of the restraining members has a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, The end of the slit is within the range of the second wide portion.

[0024] According to this aspect, since the reinforcing ribs perpendicular to the wide faces of the core material are joined at the longitudinal ends of the core material to give it a cross-shaped cross section, when the buckling restrained brace is attached to the 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, so that the rigidity of the end of the core material in the direction outward from the structural face can be increased. In the gusset plate of the structural face to which the core material with a cross-shaped cross section is attached, fin stiffeners are attached to the gusset plate, and the core material and gusset plate, and the reinforcing ribs and fin stiffeners of the buckling restrained brace are each joined by high tension bolts or the like via splice plates.

[0025] In this embodiment, a slit is provided at a position corresponding to the reinforcing rib of the wooden restraint body, and this slit is configured to prevent interference between the wooden restraint body and the reinforcing rib. This makes it possible to suppress damage or cracks that may occur around the slit in the restraint material when the frame and buckling restraint brace are deformed outside the structural plane.

[0026] For example, by having a gap of a certain width between the slit and the reinforcing rib in plan view, when the core material expands and contracts in response to deformation of the structural surface, the gap can absorb the expansion and contraction of the core material, preventing the expanding and contracting core material from coming into contact with the wall surface of the slit. Here, the setting of this gap is left to the discretion of the designer, and the amount of expansion and contraction of the core material is calculated based on the set inter-story deformation angle, and for example, the gap is set to be equal to or larger than the amount of expansion and contraction of the core material. Note that the "gap" here includes the gap between the longitudinal end of the slit and the reinforcing rib, as well as the gap between the side surface of the slit and the reinforcing rib.

[0027] Furthermore, in this embodiment, since the end of the slit is within the range of the second wide portion, in other words, the end of the slit is not located midway through the narrow portion, it is possible to prevent the highly buckled narrow portion from contacting and pressing against the end of the slit, which is a structurally weak portion of the wooden restraint body, and causing cracks and damage to the surrounding area of ​​the slit in the wooden restraint body.

[0028] In another aspect of the buckling restrained brace according to the present invention, A reinforcing rib is joined to the wide surface at the end of the longitudinal direction of the core material so as to be perpendicular to the wide surface, forming a cross-shaped cross section; A pair of the restraining members has a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, The predetermined position is characterized in that it is a position that is one or two wavelengths away from the end of the slit during higher-order buckling of the core material.

[0029] This embodiment also increases the rigidity of the end of the core material in the outward direction of the structural plane. In addition, the end of the slit is within the range of the wide portion, in other words, the end of the slit is not located in the middle of the narrow portion, and the predetermined position from the boundary with the wide portion, which is the starting point of the smooth narrowing in the narrow portion, is one or two wavelengths away from the end of the slit during high-order buckling of the core material, so that the high-order buckled narrow portion comes into contact with and presses the end of the slit, which is a structurally weak portion of the wooden restraint, and cracks are prevented from occurring in the surrounding area of ​​the slit of the wooden restraint, causing damage.

[0030] 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 corresponding ends of the pair of restraint members.

[0031] According to this aspect, the wooden restraint further has a pair of wooden side panels that connect the corresponding ends of the pair of restraining materials, so that the core material can be surrounded by the wooden restraint with a strong closed structure. Here, the wooden restraint and the side panels can be connected by adhesive, nails, screws, bolts, or a combination of these. Effect of the Invention

[0032] As can be understood from the above explanation, the buckling restraint brace of the present invention can prevent damage to the end side of the wooden restraint body that restrains the core material due to the stiffening force generated by the progression of higher-order buckling modes at the end side of the core material. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 is a perspective view illustrating an example of a core material that forms a buckling restraint brace according to an embodiment. [Figure 2A] FIG. 2 is a plan view of the core material shown in FIG. [Figure 2B] 2 is a plan view of a modified example of the core material shown in FIG. [Diagram 3] FIG. 11 is a perspective view showing another example of a core material that forms the buckling restraint brace according to the embodiment. [Figure 4A] FIG. 4 is a plan view of the core material shown in FIG. [Figure 4B] FIG. 4 is a plan view of a modified example of the core material shown in FIG. [Diagram 5] FIG. 1 is a perspective view of an example of a buckling restrained brace according to embodiments. [Figure 6] 6 is a view taken along the line VI-VI in FIG. 5, and is a longitudinal cross-sectional view of an end portion of the buckling restraint brace according to the embodiment. [Figure 7] 7 is a view taken along the line VII-VII in FIG. 5, and is a vertical cross-sectional view of the center portion of the buckling restrained brace according to the embodiment. [Figure 8] FIG. 2 is a plan view of an example of a buckling restraint brace according to an embodiment, showing the core material and spacers in a see-through view. [Figure 9] FIG. 11 is a plan view of another example of a buckling restraint brace according to an embodiment, showing the core material and spacers in a see-through manner. [Figure 10] 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 11] FIG. 1 is a diagram illustrating the deformation of the frame during a large earthquake and the additional bending moment at the buckling-restrained brace joint caused by the deformation of the frame. [Figure 12] FIG. 13 is a diagram showing the overall buckling line of the buckling restraint brace. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, a buckling restraint brace according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components are designated by the same reference numerals to avoid redundant description.

[0035] [Buckling restraint brace according to embodiment] First, an example of a buckling restrained brace according to an embodiment will be described with reference to Figs. 1 to 9. 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. 2A is a plan view of the core material shown in Fig. 1. Fig. 3 is a perspective view showing another example of a core material forming a buckling restrained brace according to an embodiment, and Fig. 4A is a plan view of the core material shown in Fig. 3. Fig. 5 is a perspective view of an example of a buckling restrained brace according to an embodiment, Fig. 6 is a view taken along the line VI-VI in Fig. 5, which is a vertical cross-sectional view of an end portion of the buckling restrained brace according to an embodiment, and Fig. 7 is a view taken along the line VII-VII in Fig. 5, which is a vertical cross-sectional view of a central portion of the buckling restrained brace according to an embodiment. Fig. 8 is a plan view of an example of a buckling restrained brace according to an embodiment, which shows a core material and a spacer in perspective.

[0036] As shown in FIG. 1, the core material 10 is formed from an elongated, 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.

[0037] 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.

[0038] On one hand, the narrow-width portion 11 has a width that smoothly narrows from the end that forms the boundary P1 with the second wide-width portion 12B to the central position O of the narrow-width portion 11. The width at the boundary P1 is t2, the width at the central position O is t1, and they are in the relationship of t1 < t2.

[0039] As clearly shown in Fig. 2A, both of the pair of end sides 11a of the narrow-width portion 11 have a curved linear shape with a predetermined curvature and have a planar shape with the minimum width at the central position O. Incidentally, the width of the second wide-width portion 12B is t3, the width of the first wide-width portion 12A is t4, and as for the entire core material 10, they are in the relationship of t1 < t2 < t3 < t4.

[0040] Here, although the end side 11a of the narrow-width portion 11 in the illustrated example has a curved linear shape, it may be a linear shape that呈 a tapered shape first and then呈 a curved shape on the central side.

[0041] From the first wide-width portion 12A to the second wide-width portion 12B, a reinforcing rib 14 perpendicular to the wide-width surface 10a is joined by welding at the central position of the wide-width surface 10a, and the wide-width portion 12呈 a cross-sectional shape.

[0042] Since the core material 10 has the narrow-width portion 11 on the central side in its longitudinal direction and the wide-width portion 12 on the end side in the longitudinal direction, the narrow-width portion 11 on the central side can be made into an area (plasticization area) where it is easy to plasticize.

[0043] Furthermore, since the narrow-width portion 11 of the core material 10 has a planar shape with a width that smoothly narrows from the end that forms the boundary P1 with the second wide-width portion 12B to its central position O, the progression of the higher-order buckling mode in the core material 10 can be started from the central side of the narrow-width portion 11. By this, the generation of the supplementary stiffening force on the end side of the core material 10 can be suppressed, and it becomes possible to suppress the damage on the end side of the wooden restraint body 20 (see Fig. 5) caused by the supplementary stiffening force. Incidentally, this will be explained again below.

[0044] In the illustrated example, the reinforcing ribs 14 are attached to the wide portion 12, and the rigidity of the wide portion 12 is further increased, which also makes the narrow portion 11 more likely to plasticize. The additional bending moment acting on the core material 10 is absorbed in the narrow portion 11, which is a plasticization region, and is particularly effectively absorbed in the central region of the narrow portion 11, which has a relatively narrow width.

[0045] 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 and a fin stiffener (see Figure 10) attached to the gusset plate, as described below.

[0046] When the buckling restraint brace 100 is attached to a gusset plate so that the wide surface 10a of the core material 10 is arranged parallel to the structural surface of the building, the core material 10 has reinforcing ribs 14 that are perpendicular to the wide surface 10a, which is parallel to the structural surface, thereby increasing the rigidity of the ends of the core material 10 in the direction outside the structural surface.

[0047] The core material 10 is preferably made of a steel material with a low yield point, such as SN material (rolled steel material for architectural structures) or LYP material (very low yield point steel material), and the yield of the core material 10 improves the earthquake energy absorption.

[0048] Fig. 2B is a plan view of a modified example of the core material shown in Fig. 1. Core material 10A in the illustrated example differs from core material 10 in that narrow width portion 11 has width-changing region 11B whose width smoothly narrows from the end portion, which is boundary P1 with second wide width portion 12B, and minimum width region 11A, which is a fixed section on the central side and has the narrowest width. Minimum width region 11A is the range between boundary P2 with left and right width-changing regions 11B, and width-changing region 11B is the range between boundaries P1 and P2.

[0049] In the minimum width region 11A, the end side 11b is straight, whereas in the width changing region 11B, the end side 11c has a curved linear shape.

[0050] Core material 10A also allows the development of a higher-order buckling mode in core material 10A to start from the center side of narrow width portion 11, and provides the same effect as core material 10.

[0051] 3 differs from core material 10 in that wide portion 12 does not have two wide portions with different widths. Also, narrow portion 11 of core material 10B has a planar shape in which the width is constant from the end portion that is the boundary P1 with wide portion 12 to a predetermined position P3 that is a predetermined distance t5 away, and the width smoothly narrows from the predetermined position P3 to a center position O of narrow portion 11.

[0052] As clearly shown in FIG. 4A, the end edge 11d on the central side of the narrow width portion 11 has a curved linear shape with a predetermined curvature, and the end edge 11e between the boundaries P3 and P1 is a straight line having a constant width of t2.

[0053] By locating boundary P3, which is the cross-sectional change point in narrow width portion 11, away from the end of reinforcing rib 14, as described below, it is possible to separate boundary P3 from slit 35 (see FIG. 5) provided in restraining material 30 of wooden restraint body 20. This makes it possible to suppress the influence of higher-order buckling on the end of wooden restraint body 20 in the relatively narrow central region which is more likely to become plastic within narrow width portion 11.

[0054] Moreover, with core material 10B, the development of the higher-order buckling mode in core material 10B can also be started from the center side of narrow width portion 11, and the same effects as those of core materials 10 and 10A can be achieved.

[0055] Fig. 4B is a plan view of a modified example of the core material shown in Fig. 3. In the illustrated example, core material 10C has narrow width portion 11 having a constant width section from boundary P1 with wide width portion 12 to a predetermined position P3 (boundary P3), has width changing region 11D whose width smoothly narrows from predetermined position P3, and has minimum width region 11C which is a constant section on the central side and has the narrowest width. Minimum width region 11C is the range between boundaries P4 between left and right width changing regions 11D, and width changing region 11D is the range between boundaries P3 and P4.

[0056] In minimum width region 11C, end side 11f is a straight line, while in width varying region 11D, end side 11g has a curved linear shape, and end side 11e of the constant width section at the end is a straight line.

[0057] Core material 10C also allows the development of the higher-order buckling mode in core material 10C to start from the center side of narrow width portion 11, and provides the same effects as core materials 10, 10A, and 10B.

[0058] 5, a pair of wooden restraining members 30 are arranged to sandwich a pair of wide surfaces 10a of core material 10, and a pair of wooden side panels 40 are connected to the ends of the pair of restraining members 30 to form a wooden restraining body 20, and a buckling restrained brace 100 is formed in which core material 10 is surrounded by the wooden restraining body 20. Note that while the illustrated example shows core material 10 as a component of buckling restrained brace 100, other forms of core materials 10A, 10B, 10C already explained may also be used.

[0059] Here, the connection between the restraint material 30 and the side plate 40 is made by one or more of adhesive, nails, screws, and bolts.

[0060] 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.

[0061] The restraining material 30 is a laminated material formed by stacking and bonding multiple laminas together. As described in detail below, the cross-sectional area, cross-sectional rigidity, Young's modulus, etc. of the wooden restraining body 20 are set so as to prevent the overall buckling of the buckling restrained brace. This Young's modulus is determined by the material of the wood. Examples of wood materials include cypress, red pine, larch, fir, and Yezo spruce.

[0062] The wooden restraint body 20 surrounds the long narrow section 11 of the steel core material 10, thereby forming a buckling restrained brace 100 with excellent appearance design. Although not shown in the figures, the narrow section 11 of the core material 10 may have protrusions on both wide faces 10a, and the wide faces of the restraint material 30 may have grooves at positions corresponding to the protrusions, so that the protrusions fit into both grooves, thereby preventing the core material 10 from shifting relative to the restraint material 30.

[0063] 6, a gap G1 of a predetermined width is provided between the slit 35 of the restraining material 30 and the reinforcing rib 14. When the structural surface to which the buckling restrained brace 100 is attached is significantly deformed in the strong axis direction or the weak axis direction, this gap G1 absorbs the deformation of the core material 10 (and the reinforcing rib 14) and prevents the reinforcing rib 14 from acting on the restraining material 30 and damaging the wooden restraining body 20.

[0064] 6, a gap G2 is provided between the wide portion 12 and the side plate 40 and between the wide portion 12 and the restraining member 30 at the end region of the core material 10. This gap G2 absorbs deformation of the core material 10 in the same manner as gap G1, and prevents the wide portion 12 of the core material 10 from acting on the side plate 40 or the restraining member 30 and damaging the wooden restraining body 20.

[0065] 7, the central region of core material 10 is restrained by wide surface 10a of core material 10 abutting against the wide surface of restraining material 30. Meanwhile, spacer 50 is interposed in gap G3 between narrow surface 10b of core material 10 and side plate 40 to prevent core material 10 from shifting toward side plate 40.

[0066] As shown in Figure 8, at the center of the core material 10, the end edge 11a of the narrow width portion 11 is curved, so that a gap exists at the center of the narrow width portion 11, while at the boundary P1 region, there is no gap between the spacer 50, the side plate 40, and the narrow width surface 10b, thereby preventing the core material 10 from shifting at this end portion.

[0067] 8, the end of slit 35 is within the range of second wide portion 12B. In other words, because the end of slit 35 is not located midway through narrow portion 11, it is possible to prevent narrow portion 11 that has undergone high-order buckling from contacting and pressing the end of slit 35, which is a structurally weak portion of wooden restraint body 20, and thus preventing cracks from occurring in the area surrounding slit 35 of wooden restraint body 20 and causing damage.

[0068] FIG. 9 is a view showing a buckling restrained brace 100A equipped with a core material 10B, in a perspective view of the core material 10B, similar to FIG.

[0069] In the buckling restrained brace 100A, the end of the slit 35 of the restraining material 30 is also within the range of the wide portion 12. That is, the end of the slit 35 is not located midway through the narrow portion 11, and in addition, a predetermined position P3 from the boundary P1 with the wide portion 12, which is the starting point where the narrow portion 11 starts to smoothly narrow in width, is located a predetermined distance t6 away from the end of the slit 35 and from the core material 10B. This prevents the highly buckled narrow portion 11 from coming into contact with and pressing the end of the slit 35, which is a structurally weak portion of the wooden restraining body 20, causing cracks in the area surrounding the slit 35 of the wooden restraining body 20 and causing damage.

[0070] Here, the predetermined distance t6 is preferably set to about one or two wavelengths at the time of higher-order buckling.

[0071] [Framework incorporating buckling restraint braces] Next, an example of a building frame incorporating a buckling restrained brace 100 will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a diagram showing a state in which a buckling restrained brace according to the embodiment is incorporated into the frame of a wooden building or the like. Fig. 11 is a diagram explaining the deformation of the frame during a major earthquake and the additional bending moment at the buckling restrained brace joint caused by the deformation of the frame. The buckling restrained brace of the illustrated example may be incorporated into the frame of a steel (S: Steel) building, a reinforced concrete building, or a steel reinforced concrete (SRC) building, in addition to the frame of a wooden building.

[0072] The frame S shown in Fig. 10 is formed of 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 joined by welding to the surface of the gusset plates GP so as to be perpendicular to the surface. The fin stiffeners FS are joined to the gusset plates GP so that their cores L3 intersect with the intersection O between the column center L1 of the column C and the beam center L2 of the beam B. The buckling restraint brace 100 is also arranged linearly passing through both intersections O at diagonal positions.

[0073] 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 the splice plate SP.

[0074] As shown in Figure 11, when a large earthquake occurs, the structural plane is deformed, and an additional bending moment shown in the following equation (1) can act on a buckling-restrained brace joint if the joint is considered to be rigid.

[0075]

number

[0076] According to the buckling restrained brace 100, the core material 10 is restrained by a wooden restraining body 20 (wooden restraining material) including a pair of wooden restraining materials 30 (restraining plates), which can suppress global buckling of the buckling restrained brace 100, and therefore the buckling restrained brace 100 has the strength against both global buckling and higher-order buckling of the core material 10. This makes it possible to form a frame S with excellent earthquake resistance.

[0077] [Consideration of overall buckling] Next, we will explain the design method for preventing global buckling of the buckling restrained brace.

[0078] When designing a buckling restrained brace, it is designed to satisfy the following equation (2) so that global buckling of the buckling restrained brace does not occur.

[0079]

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[0080] Here, the bending moment acting on the center of the restraint material (restraint plate) can be expressed by the following equation (3).

[0081]

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[0082] The condition for preventing the overall buckling of the wooden restraint body (wooden restraint material) is to satisfy the following equation (4).

[0083]

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[0084] Equation (4) is shown in Figure 12 as the global bending stress line of the buckling restrained brace. In Figure 12, the upper side of the global bending stress line is the safe zone, and the lower side is the dangerous zone, and the design axial force of the wooden restraint body, Euler load, length of the general part of the core material, and yield bending strength of the wooden restraint body are set so as to fall within the safe zone. Note that the global bending stress line of the buckling restrained brace shown in Figure 12 applies to both global buckling in the weak axis direction and global buckling in the strong axis direction of the core material.

[0085] In addition to examining the relationship between the yield bending strength of the wooden restraint body and the bending moment acting on it as described above, 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 at the time of core material yielding (formula omitted).

[0086] [Study on the crushing failure of wooden restraints] Next, a method for evaluating the compressive failure of a wooden restraint body (wooden restraining material) will be described. In the buckling restrained brace 100, etc., in order to prevent the wooden restraint body from being destroyed due to the core material compressing into the wooden restraint body, it is verified that the following formula (5) is satisfied.

[0087]

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[0088] Here, in addition to examining the relationship between the compressive strength of the restraining material (restraint plate) and the stiffening force acting as described above, it is also advisable to also examine that the short-term allowable compressive strength of the restraining material will be greater than the stiffening force acting at the time of core material yielding (formula omitted).

[0089] In addition, the present invention is not limited to the configuration shown here, and may be implemented in other embodiments in which other components are combined with the configurations and the like of the above-mentioned embodiment. In this regard, the present invention may be modified within the scope of the gist of the present invention, and may be appropriately determined according to the application form. [Explanation of symbols]

[0090] 10, 10A, 10B, 10C: Core material 10a: Wide surface 10b:Narrow side 11: Narrow section 11A, 11C: Minimum width area 11B, 11D: Width change area 11a, 11b, 11c, 11d, 11e, 11f, 11g: Edge 12: Wide section 12A: First wide section (wide section) 12B: Second wide section (wide section) 12a: Bolt hole 14: Reinforcement rib 14a: Bolt hole 20: Wooden restraints 30: Restraint material 35: Slit 40: Side panel 50: Spacer 100,100A: Buckling restraint brace A: Plasticization region G1, G2, G3: Gap 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 of a pair of restraining members made of wood and arranged so as to face at least two wide surfaces of the core material; 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 has a wide portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, the wide portion having a first wide portion at the end and a second wide portion relatively narrower than the first wide portion; A buckling restraint brace, characterized in that the narrow width portion smoothly narrows in width from the end portion that is the boundary with the second wide width portion to a central position of the narrow width portion.

2. A steel plate-shaped core material, a wooden restraining body formed of a pair of restraining members made of wood and arranged so as to face at least two wide surfaces of the core material; 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 has a wide portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, the wide portion having a first wide portion at the end and a second wide portion relatively narrower than the first wide portion; A buckling restraint brace, characterized in that the narrow width portion has a width change region in which the width smoothly narrows from the end portion which is the boundary with the second wide width portion, and a minimum width region of a certain section toward the center which is the narrowest.

3. A steel plate-shaped core material, a wooden restraining body formed of a pair of restraining members made of wood and arranged so as to face at least two wide surfaces of the core material; The core material has a narrow width portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide width portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, A buckling restraint brace, wherein the narrow width portion smoothly narrows in width from a predetermined position on the end side of the narrow width portion to a central position of the narrow width portion.

4. A steel plate-shaped core material, a wooden restraining body formed of a pair of restraining members made of wood and arranged so as to face at least two wide surfaces of the core material; The core material has a narrow width portion at a center side in a longitudinal direction, where the width of the wide surface is relatively narrow, and has a wide width portion at an end side in a longitudinal direction, where the width of the wide surface is relatively wide, This is a buckling restraint brace, characterized in that the narrow width portion has a width change region where the width smoothly narrows from a predetermined position on the end side, and a minimum width region of a certain section on the central side where the width is the narrowest.

5. A reinforcing rib is joined to the wide surface at the end of the longitudinal direction of the core material so as to be perpendicular to the wide surface, forming a cross-shaped cross section; A pair of the restraining members has a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, The buckling restraint brace according to claim 1 or 2, characterized in that an end of the slit is within the range of the second wide portion.

6. A reinforcing rib is joined to the wide surface at the end of the longitudinal direction of the core material so as to be perpendicular to the wide surface, forming a cross-shaped cross section; A pair of the restraining members has a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, 5. The buckling restraint brace according to claim 3 or 4, characterized in that the predetermined position is one or two wavelengths away from the end of the slit during higher-order buckling of the core material.

7. The buckling restraint brace according to claim 1 , wherein the wooden restraint body further comprises a pair of wooden side panels connecting corresponding ends of the pair of restraining members.

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