Buckling Restrained Brace

Abstract

To provide a buckling restraining brace that is suitable for use by being incorporated in a frame of a wooden building or the like and capable of reducing the number of bolts for connecting a restraining plate and a side plate forming a wooden restraining material.SOLUTION: A buckling restraining brace 100 includes: a core material 10 formed of steel and having a plate shape; and a wooden restraining material 20 formed by a pair of wooden restraining plates 21 arranged so as to face two wide surfaces 11a included in the core material 10, and a plurality of first clamps 29A that are arranged so as to face two narrow surfaces 11b included in the core material 10 and connect the pair of restraining plates 21 in a longitudinal direction of the restraining plates 21.SELECTED DRAWING: Figure 3

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 houses 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's intended use (e.g., residential). However, the improved fire resistance and earthquake resistance are one factor driving increased interest in wooden buildings, including wooden houses. When incorporating the conventional buckling restrained braces described above into the frame of such a wooden house, wooden columns and beams are mixed with buckling restrained braces with metal or concrete stiffeners, resulting 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 use a lot of metal, concrete, mortar, etc., and installing heavy buckling restrained braces inside the lightweight wooden beams and columns that make up a wooden house 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] The wooden restraint material that surrounds the steel core material that forms a conventional buckling restraint brace is composed of a pair of restraint plates that face the two wide surfaces of the core material, and a pair of side plates that connect the ends of the pair of restraint plates.However, when attempting to form the wooden restraint material into a strong closed structure in order to increase the restraint effect of the core material, it is often necessary to increase the number of bolts that connect the pair of restraint plates and the pair of side plates together with the restraint plates.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a buckling restraint brace that is suitable for use in incorporating into the framework of a wooden building or the like, and that can reduce the number of bolts required to connect a pair of restraint plates that form a wooden restraint member. [Means for solving the problem]

[0009] 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, The structure is characterized by comprising a wooden restraining material formed by a pair of wooden restraining plates arranged to face the two wide sides of the core material, and a plurality of first rivets arranged to face the two narrow sides of the core material and connecting the pair of restraining plates along their longitudinal direction.

[0010] According to this aspect, a pair of restraint plates that form the wooden restraint material are connected to each other by a plurality of first clamps arranged along their longitudinal direction, thereby reducing the number of bolts that connect the restraint plates to each other or eliminating the need for bolts while firmly connecting the pair of restraint plates.

[0011] In this embodiment, a steel core is surrounded by a wooden restraint member formed by a pair of restraint plates. With this configuration, even when the buckling restrained brace of this embodiment is applied to the frame of a wooden building, there is no risk of it appearing out of place with the frame components. Here, the restraint plates may be made of solid wood or laminated lumber with laminated lamina.

[0012] Furthermore, in this embodiment, the wooden restraint member is formed, for example, from a pair of plate-shaped restraint plates, which facilitates processing of the wooden restraint member. For example, the buckling restrained brace described in Patent Document 1 requires processing laminated timber to create two wooden restraint members with an L-shaped cross section, turning them upside down, and connecting them with a core material sandwiched between them. In contrast, the buckling restrained brace of this embodiment can be produced by, for example, connecting a pair of plate-shaped restraint plates with a first fastener while a core material is interposed between them, thereby producing the wooden restraint member and simultaneously producing the buckling restrained brace. This makes the production of the buckling restrained brace even easier.

[0013] In this embodiment, first fasteners are driven into the corresponding side surfaces (end faces) of a pair of restraint plates, so that the two piercing portions of the first fasteners penetrate into the pair of restraint plates to connect the pair of restraint plates. Here, the pair of restraint plates may be connected to each other with separate bolts, but these bolts are not essential for the manufacture of conventional wooden restraint materials and are used as a fail-safe to prevent the pair of restraint plates from separating in the event of a major earthquake, for example. Therefore, even when bolts are used, the number of bolts can be significantly fewer than in conventional buckling-restrained braces.

[0014] In another aspect of the buckling restrained brace according to the present invention, The first rivets are arranged in a V-shape or an inverted V-shape along the longitudinal direction of the wooden restraint material, forming a rivet truss.

[0015] According to this aspect, the first rivets are arranged in a V-shape or an inverted V-shape along the longitudinal direction of the wooden restraint material to form a rivet truss, thereby forming a firmly integrated wooden restraint material and increasing the cross-sectional rigidity of the core material in the wooden restraint material in both the strong axis direction and the weak axis direction.

[0016] In another aspect of the buckling restrained brace according to the present invention, The clamp truss is formed on the center side of the wooden restraint material in the longitudinal direction, The wooden restraint member is characterized in that a plurality of second clamps extending in a direction perpendicular to the wide surface connect the ends of the pair of restraint plates to each other on the end side.

[0017] According to this aspect, at the end side of the wooden restraint material, multiple second rivets extending in a direction perpendicular to the wide surface of the core material connect the ends of a pair of restraint plates, so that the ends of the pair of restraint plates are reinforced by the multiple second rivets.This makes it possible to suppress cracks (splitting) that may occur at the ends of the pair of restraint plates, which receive the strongest pushing force from the core material when the frame and buckling restraint brace are deformed outside the structural plane.

[0018] In another aspect of the buckling restrained brace according to the present invention, 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 restraint plate is provided with a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, The restraint plate is characterized in that a plurality of third rivets are attached to straddle the slits.

[0019] According to this aspect, the longitudinal ends of the core material have a cross-shaped cross section due to the reinforcing ribs that are perpendicular to the wide faces of the core material. Therefore, when a buckling-restrained brace is attached to a gusset plate with the wide faces of the core material arranged parallel to the structural face of a building, the core material has reinforcing ribs that are perpendicular to the wide faces that are parallel to the structural face, thereby increasing the rigidity of the end of the core material in the outward direction of the structural face. In the gusset plate of the structural face to which the core material with a cross cross section is attached, fin stiffeners are attached to the gusset plate, and the core material of the buckling-restrained brace and the gusset plate, as well as the reinforcing ribs and fin stiffeners, are each joined via a splice plate with high-tension bolts or the like. In this aspect, slits are provided in the wooden restraint material at positions corresponding to the reinforcing ribs, and these slits are configured to prevent interference between the wooden restraint material and the reinforcing ribs.

[0020] Furthermore, according to this embodiment, by attaching multiple third clamps across the slits, the periphery of the slits provided in the restraint plate to prevent interference with the reinforcing ribs can be reinforced with multiple third clamps, making it possible to suppress cracks that may occur around the slits in the restraint plate when the frame and buckling restraint brace are deformed outside the structural plane.

[0021] In another aspect of the buckling restrained brace according to the present invention, A decorative plate that conceals the first and second clamps is attached to the side of the pair of restraining plates.

[0022] According to this aspect, the decorative panels are attached to the sides of the pair of restraint plates to conceal the first and second rivets, further improving the appearance design of the buckling restrained brace. This decorative panel is attached to the sides of the pair of restraint plates in the same way as the side panels in conventional buckling restrained braces, but because it is not a component that requires the same strength as conventional side panels, the thickness of the decorative panel can be thin.

[0023] In another aspect of the buckling restrained brace according to the present invention, The two piercing portions of each of the first, second and third rivets are driven into and fixed to the restraint plate, or the two piercing portions of each of the first, second and third rivets are inserted into fixing holes opened in the restraint plate and fixed by adhesive.

[0024] According to this aspect, the fastener can be fixed to the restraint plate in either of two ways: by hammering in the piercing portion of the fastener, or by inserting the piercing portion into a fixing hole opened in the restraint plate and adhesively fixing it. In either way, the fastener can be firmly fixed to the restraint plate.

[0025] For example, in a configuration in which the piercing portion of the clamp is driven in and fixed, the clamp can be easily fixed to the side surface of the restraint plate or around the slit.

[0026] On the other hand, in a configuration in which the piercing portions are inserted into fixing holes opened in the restraint plates and adhesively fixed, there is no risk of the side surfaces of the restraint plates being damaged by the driving force when the fasteners are driven in, and the initial rigidity of the restraint plates around the points of fixation by the fasteners can be maintained. That is, fixing holes are opened on the side surfaces of the pair of restraint plates and around the slits, and the piercing portions of the fasteners are inserted into the fixing holes and adhesively fixed, so that the piercing portions are adhesively fixed to the restraint plates, the side surfaces of the pair of restraint plates are fixed together via the first and second fasteners, and the areas around the slits in the restraint plates are reinforced with the third fastener.

[0027] In another aspect of the buckling restrained brace according to the present invention, a non-contact groove that does not come into contact with the wide surface of the core material is provided at an end of the restraint plate; The area of ​​the restraint plate other than the non-contact groove is in contact with the wide surface of the core material.

[0028] According to this aspect, non-contact grooves are provided at the ends of the restraint plates that do not come into contact with the wide surfaces of the core material, and the areas of the restraint plates other than the non-contact grooves are in contact with the wide surfaces of the core material. Therefore, when the frame and the buckling restrained brace deform outward from the structural plane, the non-contact grooves are provided at the ends of the restraint plates that receive the strongest pushing force from the core material. This eliminates or reduces contact between the core material and the restraint plates, thereby suppressing cracks that may occur at the ends of the restraint plates. In particular, the aforementioned configuration in which the ends of the pair of restraint plates are reinforced with multiple second fasteners, combined with the configuration in which the non-contact grooves at the ends of the restraint plates that do not come into contact with the wide surfaces of the core material, further enhances the effect of suppressing cracks that may occur at the ends of the restraint plates. Here, non-contact grooves are provided at the ends of each of the pair of restraint plates facing the two wide surfaces of the core material in areas where the core material may come into contact with the restraint plates when the buckling restrained brace deforms outward from the structural plane.

[0029] The non-contact grooves at the ends of the restraint plate eliminate or reduce contact (prevent strong contact) between the ends of the restraint plate and the core material, while the areas of the restraint plate other than the non-contact grooves abut against the core material, ensuring that the restraint plate prevents the core material from buckling.

[0030] 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, The non-contact groove extends from an edge of the restraint plate to a position corresponding to the boundary between the wide portion and the narrow portion of the core material.

[0031] According to this aspect, the core material has a narrow portion at the center of its longitudinal direction, where the width of the wide surface is relatively narrow, and a wide portion at its longitudinal end, where the width of the wide surface is relatively wide. This allows the narrow portion at the center to be a region that is easily plasticized, and further allows the plasticization region to be limited to the narrow portion at the center. Furthermore, 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, so that this transition region can absorb additional bending moments acting on the core material. Additional bending moments (or simply, additional bending) refer to bending moments that can act on the wooden restraint material due to large deformation of the frame and buckling-restrained braces, for example, during a major earthquake. Thus, in this aspect, additional bending moments acting on the core material can be effectively absorbed by the boundary region between the wide portion and the narrow portion of the core material.

[0032] While the core material has a wide section and a narrow section, the restraint plate has a non-contact groove extending from its edge to a position corresponding to the boundary between the wide section and the narrow section of the core material, thereby making it possible to eliminate with a high degree of certainty the contact (pushing) of the core material against the end of the restraint plate.

[0033] Another aspect of the buckling restrained brace according to the present invention is: In plan view, a gap is formed between the slit and the reinforcing rib.

[0034] According to this aspect, the gap between the slit and the reinforcing rib allows the core material to absorb expansion and contraction in response to structural deformation. This eliminates the problem of the expanding and contracting core material contacting the wall of the slit and damaging the wooden restraint material. The design of this gap is left to the discretion of the designer, who calculates the amount of expansion and contraction of the core material based on the set story deformation angle. For example, the gap is set to be equal to or greater than the amount of expansion and contraction of the core material. Note that the "gap" here includes the gap between the longitudinal ends of the slit and the reinforcing rib, as well as the gap between the side surfaces of the slit and the reinforcing rib. Additionally, the non-contact grooves in the restraint plate create a separate gap between the core material and the restraint plate. This gap is also set to a size that prevents the core material from strongly pressing against or abutting the restraint plate when the buckling-restrained brace deforms during a major earthquake.

[0035] In addition, another aspect of the buckling restrained brace according to this aspect is as follows: The present invention is characterized in that an insert plate is interposed between the wide surface of the core material and the restraining plate.

[0036] According to this aspect, the core material's high-order buckling deformation causes localized compressive forces to act on the restraining plate, preventing damage to the restraining plate due to these localized forces. By interposing the insert plate between the wide surface of the core material and the restraining plate, the force acting from the convex portion of the core material's high-order buckling deformation is first transmitted to the insert plate, which then spreads within the insert plate, and the diffused force within the insert plate acts on the wooden restraining plate. This effectively prevents damage to the wooden restraining plate due to multiple localized forces acting from the core material. [Effects of the Invention]

[0037] As can be seen from the above explanation, the buckling restraint brace of the present invention is suitable for use in a wooden building or other structure, and can reduce the number of bolts required to connect the pair of restraint plates that form the wooden restraint member. [Brief explanation of the drawings]

[0038] [Figure 1] FIG. 1 is a perspective view showing an example of a core material that forms a buckling restrained brace according to an embodiment, together with a spacer. [Figure 2] FIG. 1 is a perspective view of an example of a wooden restraint member that forms a buckling restrained brace according to embodiments. [Figure 3] FIG. 1 is a perspective view of an example of a buckling restrained brace according to embodiments. [Figure 4] FIG. 4 is a view taken in the direction of the arrow IV in FIG. 3. [Figure 5] FIG. 4 is a view taken along arrows VV in FIG. 3. [Figure 6] FIG. 6 is a view taken along the line VI-VI in FIG. 3. [Figure 7] FIG. 7 is a view taken along the line VII-VII in FIG. 3. [Figure 8] FIG. 8 is a view taken along the line VIII-VIII in FIG. 3. [Figure 9] 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 10] 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 11] FIG. 10 is a diagram showing the overall buckling line of the buckling restraint brace. DETAILED DESCRIPTION OF THE INVENTION

[0039] 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.

[0040] [Buckling restrained brace according to the embodiment] <Core material> First, an example of a core material that forms a buckling restrained brace according to an embodiment will be described with reference to Fig. 1. Here, Fig. 1 is a perspective view showing an example of a core material that forms a buckling restrained brace according to an embodiment, together with a spacer.

[0041] The core material 10 is formed from a slender, plate-shaped flat steel, and has a narrow portion 13 in the center in the longitudinal direction where the wide surface 11a is relatively narrow, and wide portions 12 in the end portions in the longitudinal direction where the wide surface 11a is relatively wide. In addition, reinforcing ribs 14 perpendicular to the wide surface 11a are welded to the wide surface 11a at the end portions in the longitudinal direction of the core material 10, giving it a cross-shaped cross section. Here, the wide portion may have a multi-step shape where the width increases toward the end portions.

[0042] By having a narrow width portion 13 at the center of the core material 10 in the longitudinal direction and a wide width portion 12 at the end of the longitudinal direction, the narrow width portion 13 at the center can be made into a region that is easily plasticized, and further, the plasticized region can be limited to the narrow width portion 13 at the center.

[0043] Furthermore, as will be explained below, the wide portion 12 and the reinforcing rib 14 each have bolt holes 12a, 14a for bolting via a splice plate to a gusset plate provided on the structural face or a fin stiffener (see FIG. 9) attached to the gusset plate. When the buckling restrained brace 100 is attached to a gusset plate so that the wide surface 11a 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 11a that is parallel to the structural face, thereby increasing the rigidity of the end of the core material 10 in the direction outward from the structural face.

[0044] 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), which improves earthquake energy absorption due to yielding of the core material 10.

[0045] Thin, rectangular column-shaped spacers 16 are arranged in the X1 direction on both sides of the narrow portion 13, and the core material 10 is housed inside a wooden restraint material (described below) with the spacers 16 arranged on both sides of the narrow portion 13. The spacers 16 may be either steel or wooden. The spacers 16 may also have a shape other than that shown in the illustration, such as a cylindrical shape. The spacers 16 have a plurality of bolt holes 16a spaced apart along their length, through which bolts (described below) are inserted.

[0046] <Wooden restraint material> Next, an example of a wooden restraint member that forms the buckling restrained brace according to the first embodiment will be described with reference to Fig. 2. Here, Fig. 2 is a perspective view of an example of a wooden restraint member that forms the buckling restrained brace according to the first embodiment.

[0047] The wooden restraint member 20 has a pair of restraint plates 21, and the core material 10 is arranged in a gap 25 between the pair of restraint plates 21. The pair of wooden restraint plates 21 are arranged so as to face the two wide surfaces 11a (see FIG. 1) of the core material 10. On the other hand, a pair of wooden decorative panels 22 bonded to the pair of restraint plates 21 are arranged so as to face the two narrow surfaces 11b (see FIG. 1) of the core material 10.

[0048] A plurality of first rivets 29A are driven into the corresponding side surfaces 21a of the pair of restraint plates 21, connecting them along the longitudinal direction.

[0049] More specifically, the first rivets 29A are arranged in a V-shape to form a rivet truss along the longitudinal direction of the wooden restraint member 20. Here, the first rivets 29A may also be arranged in an inverted V-shape.

[0050] The above-mentioned rivet truss is formed by a plurality of first rivets 29A at the center of the longitudinal direction of the wooden restraint member 20. Meanwhile, at the end of the wooden restraint member 20, a plurality of second rivets 29B extending in a direction perpendicular to the wide surface 11a of the core material 10 connect the ends of the pair of restraint plates 21.

[0051] A pair of restraint plates 21 constituting the wooden restraint material 20 are connected to each other by a plurality of first rivets 29A arranged in a V-shape on their left and right sides 21a to form a rivet truss, thereby enabling a firm connection while reducing or eliminating the number of bolts connecting the pair of restraint plates 21.

[0052] In the illustrated example, bolt holes 21b with counterbores are opened at corresponding positions on the pair of restraint plates 21, a washer 32 is disposed in the counterbore of bolt hole 21b, and bolt 31 is inserted through washer 32, while a washer 34 is disposed in the counterbore of the other bolt hole 21b, and a nut 33 is fastened to the thread groove at the tip of bolt 31 protruding outward from washer 34. This bolt connection functions as a fail-safe to prevent the pair of restraint plates 21 from separating in the event of a major earthquake, and the main means for connecting the pair of restraint plates 21 to each other are the multiple first rivets 29A.

[0053] The second vertical rivets 29B are arranged at a pitch interval that is narrower than that of the first rivets 29A, so that the end of the wooden restraining member 20 is restrained by the second rivets 29B that are arranged as closely as possible.

[0054] Furthermore, at the end of the restraint plate 21, a slit 24 is provided at a position that corresponds to the reinforcing rib 14 when the core material 10 is accommodated in the gap 25, so as not to interfere with the reinforcing rib 14. A plurality of third nails 29C are further driven in to reinforce the periphery of this slit 24.

[0055] The first clamp 29A, the second clamp 29B, and the third clamp 29C are all metal fittings that are generally U-shaped and have a linear connecting portion 29a and two piercing portions 29b formed by bending the connecting portion 29a at right angles at both ends.

[0056] Here, the first clamp 29A, the second clamp 29B, and the third clamp 29C may be fixed by hammering or by inserting the piercing portions 29b into fixing holes (not shown) formed on the side surface 21a of the restraint plate 21 or around the slit 24, and then adhesively fixing them with an adhesive. Here, a urethane adhesive or an epoxy adhesive is used as the adhesive filled in the fixing holes.

[0057] In addition, non-contact grooves 23 that do not come into contact with the wide surface 11a of the core material 10 housed in the gap 25 are provided at both ends of the restraint plate 21, and the area of ​​the restraint plate 21 other than the non-contact grooves 23 (the area on the central side) comes into contact with the wide surface 11a of the core material 10. This configuration and the effects achieved by this configuration will be described in detail below.

[0058] The restraint plate 21 may be made of either solid wood or a wood material including laminated lumber made of laminated lamina. As will be described in detail below, the cross-sectional area, cross-sectional stiffness, Young's modulus, etc. of the wooden restraint member 20 are set so as to prevent global buckling of the buckling-restrained brace. The Young's modulus is determined by the wood material. Examples of wood materials include Japanese cypress, red pine, larch, fir, and Yezo spruce.

[0059] After the pair of restraint plates 21 are connected together with a plurality of first fasteners 29A and second fasteners 29B, a pair of decorative plates 22 that conceal the first fasteners 29A and second fasteners 29B are adhered to the side surfaces 21a of the pair of restraint plates 21. Here, the decorative plates 22 are formed, for example, from wood, which is the same material as the restraint plates 21. Furthermore, a urethane adhesive or an epoxy adhesive is used as the adhesive that adheres the decorative plates 22 to the side surfaces 21a of the restraint plates 21.

[0060] The decorative panel 22 conceals the first rivets 29A and the second rivets 29B, further improving the aesthetic design of the wooden restraint member 20. Note that the installation of the decorative panel 22 is optional, and if aesthetic design is not an issue, the installation of the decorative panel 22 is not necessary.

[0061] <Buckling restrained brace> Next, an example of a buckling-restrained brace according to an embodiment, formed using the core material 10 and wooden restraint material 20 described above, will be described with reference to Figures 3 to 8. Here, Figure 3 is a perspective view of an example of a buckling-restrained brace according to an embodiment. Also, Figures 4, 5, 6, 7, and 8 are a view taken in the direction of arrow IV in Figure 3, a view taken in the direction of arrows VV in Figure 3, a view taken in the direction of arrows VI-VI in Figure 3, a view taken in the direction of arrows VII-VII in Figure 3, and a view taken in the direction of arrows VIII-VIII in Figure 3, respectively.

[0062] The buckling restraint brace 100 is constructed such that wooden restraint members 20 are arranged to surround the narrow section 13 and part of the wide section 12 of the core material 10, and the cross-shaped portion of the end of the wide section 12 extends beyond the end of the wooden restraint member 20, with the bolt holes 12a, 14a of the wide section 12 and reinforcing rib 14 that extend outward facing the outside.

[0063] A core material 10 is arranged in the gap 25 between a pair of restraint plates 21, and a first clamp 29A and a second clamp 29B connect the corresponding sides 21a of the pair of restraint plates 21. Furthermore, a bolt 31 is inserted into the bolt hole 21b and tightened with a nut 33, thereby forming a buckling restraint brace 100.

[0064] The buckling-restrained brace 100 has a pair of restraint plates 21 connected by multiple first rivets 29A that form a rivet truss, and the core material 10 is surrounded by wooden restraint members 20 with high cross-sectional rigidity, resulting in a buckling-restrained brace with high buckling strength. Furthermore, the ends of the pair of restraint plates 21 are firmly connected by multiple closely spaced second rivets 29B, resulting in a buckling-restrained brace with a strong closed structure at the ends. Furthermore, because the steel core material 10 is surrounded by wooden restraint members 20, the buckling-restrained brace 100 does not appear out of place with the structural components, even when applied to the frame of a wooden building.

[0065] A gap G1 having a width t1 is provided between the side surface of the wide portion 12 of the core material 10 and the wooden restraint material 20.

[0066] Furthermore, non-contact grooves 23 are formed at the ends of the constraining plates 21 to prevent the constraining plates 21 from contacting the wide portions 12 of the core material 10, and a gap G3 of height t2 is provided between the non-contact grooves 23 and the wide portions 12. As shown in detail in Figure 7, these non-contact grooves 23 are provided in a range from the edge of the constraining plates 21 to a position corresponding to the additional bending absorption area A of the core material 10 (boundary region A between the wide portions 12 and the narrow portions 13).

[0067] 7 and 8, the boundary region A between the wide section 12 and the narrow section 13 is a transition region where the planar area and cross-sectional area of ​​the core material 10 change, and therefore serves as an additional bending absorption area where the additional bending moment acting on the core material 10 can be absorbed in this transition region. In this way, the additional bending moment acting on the core material 10 is effectively absorbed in the boundary region A between the wide section 12 and the narrow section 13 of the core material 10, and the gap G1 provided between the core material 10 and the end of the wooden restraint member 20 prevents the additional bending moment acting on the core material 10 from acting on the end of the wooden restraint member 20.

[0068] Furthermore, a gap G2 having a width t3 in the longitudinal direction of the reinforcing rib 14 and a width t1 on one side of the reinforcing rib 14 is provided between the reinforcing rib 14 and the slit 24 in the restraining plate 21 of the wooden restraining member 20. By providing gap G1 between the side of the wide section 12 and the wooden restraining member 20, if the structural surface to which the buckling restrained brace 100 is attached undergoes significant deformation, this gap G1 can absorb the deformation of the core material 10, preventing so-called additional bending moment from acting on the wooden restraining member 20. On the other hand, the presence of gap G2 between the slit 24 and the reinforcing rib 14 allows gap G2 to absorb the expansion and contraction of the core material 10 when it expands and contracts in response to deformation of the structural surface, eliminating the problem of the expanding and contracting core material 10 coming into contact with the wall of the slit 24 and causing damage to the wooden restraining member 20.

[0069] 4 and 5, in the buckling restrained brace 100, non-contact grooves 23 are provided in the restraint plate 21 over the range from its edge to a position corresponding to the additional bending absorption area A of the core material 10. Meanwhile, as shown in FIG. 6, the area of ​​the restraint plate 21 other than the non-contact grooves 23 is in contact with the narrow portion 13 of the core material 10.

[0070] With the above configuration, when the frame S (see Figure 9) and the buckling restraint brace 100 are deformed outside the structural plane, the non-contact groove 23 eliminates or reduces contact (prevents strong contact) between the core material 10 and the restraint plate 21 at the end of the restraint plate 21, which is likely to receive the strongest pushing force from the core material 10.

[0071] In this way, the pressing force from core material 10 onto restraint plate 21 is eliminated or alleviated, thereby making it possible to suppress cracks that may occur at the end of restraint plate 21.

[0072] In the illustrated example, the ends of a pair of restraint plates 21 are connected (reinforced) by clamps 29B driven into the outside of the side surfaces 21a, and this reinforcing structure, combined with the non-contact grooves 23 which eliminate or reduce contact between the core material 10 and the restraint plates 21, further enhances the effect of suppressing cracks at the ends of the restraint plates 21.

[0073] In addition, the non-contact grooves 23 at the ends of the restraint plate 21 eliminate or reduce the contact between the ends of the restraint plate 21 and the core material 10, while the areas of the restraint plate 21 other than the non-contact grooves 23 (the central areas) come into contact with the core material 10, thereby ensuring that the restraint plate 21 can prevent the core material 10 from buckling.

[0074] 7 and 8, by providing narrow section 13 at the center of core material 10, a relatively large gap G4 (larger than gap G1 on the side of wide section 12 at the end of core material 10) exists on the side of narrow section 13. By interposing spacer 16 in gap G4 and closing gap G4, it is possible to prevent buckling in the strong axis direction of core material 10 (the direction parallel to wide surface 11a of core material 10). As a result, global buckling of buckling-restrained brace 100 is suppressed and the compressive strength of buckling-restrained brace 100 is improved, thereby providing excellent seismic reinforcement for a frame incorporating buckling-restrained brace 100 and a building including this frame.

[0075] Although not shown in the figures, in the buckling restrained brace 100, an insert plate may be interposed between the wide surface 11a of the core material 10 and the inner surface of the restraint plate 21. The insert plate may be either a steel plate or a wooden plate, and the wooden plate may be, for example, LVL (Laminated Veneer Lumber).

[0076] Due to the high-order buckling deformation of the core material 10, a pressing force acts locally on the inner surface of the restraining plate 21 from the core material 10, and there is a risk that this local pressing force may cause damage to the restraining plate 21. In contrast, by interposing an insert plate between the core material 10 and the restraining plate 21, the pressing force acting from the convex portion during the high-order buckling deformation of the core material 10 is first transmitted to the insert plate, and the transmitted pressing force spreads inside the insert plate, and the pressing force diffused inside the insert plate acts as a dispersed force on the wooden restraining plate 21. This effectively prevents damage to the wooden restraining plate 21 due to multiple local pressing forces acting from the core material 10.

[0077] <Example of application of buckling restrained braces to a frame> Next, an example of application of a buckling restrained brace to a frame will be described with reference to Figures 9 and 10. Here, Figure 9 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 10 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.

[0078] The frame S shown in Figure 9 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.

[0079] 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.

[0080] As shown in Figure 10, 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.

[0081]

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[0082] According to the buckling-restrained brace 100, a gap G1 of width t1 is provided on the side of the wide section 12 of the core material 10. This allows gap G1 to absorb the deformation of the core material 10 when the structural surface to which the buckling-restrained brace 100 is attached undergoes significant deformation, preventing additional bending moments from acting on the wooden restraining members 20. Furthermore, a gap G2 of width t2 in the longitudinal direction of the reinforcing rib 14 is provided between the reinforcing rib 14 and the slit 24 in the restraining plate 21 of the wooden restraining member 20, and of width t1 is provided on the side of the reinforcing rib 14. This allows gap G2 to absorb the expansion and contraction of the core material 10 when it expands and contracts in response to deformation of the structural surface, eliminating the problem of the expanding and contracting core material 10 coming into contact with the wall of the slit 24 and causing damage to the wooden restraining member 20. Furthermore, the ends of the restraint plate 21, which are likely to receive the strongest pushing force from the core material 10, are connected by multiple second rivets 29B, and gaps G3 are formed by non-contact grooves 23 at these ends.Gap G3 eliminates or reduces contact between the core material 10 and the restraint plate 21, thereby effectively suppressing cracks that may occur at the ends of the restraint plate 21.

[0083] [Study of overall buckling] Next, we will explain the design method for preventing global buckling of buckling-restrained braces.

[0084] When designing a buckling-restrained brace, the following formula (2) must be satisfied to prevent global buckling of the buckling-restrained brace.

[0085]

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[0086] Here, the bending moment acting on the center of the restraint plate can be expressed by the following equation (3).

[0087]

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[0088] The condition for preventing the overall buckling of the wooden restraint member is to satisfy the following equation (4).

[0089]

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[0090] Equation (4) is shown in Figure 11 as the global bending stress curve for the buckling-restrained brace. In Figure 11, 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 member, the Euler load, the length of the general part of the core member, and the yield bending strength of the wooden restraint member 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 11 applies to both global buckling in the weak axis direction of the core member and global buckling in the strong axis direction.

[0091] In addition to examining the relationship between the yield bending strength of the wooden restraint material and the bending moment acting on it, it is also advisable to examine the fact that the short-term allowable bending strength of the wooden restraint material will be greater than the bending moment acting on it when the core material yields (formula omitted).

[0092] <Study on the compressive failure of wooden restraints> Next, we will explain how to evaluate the failure of wooden restraints due to the core material penetrating into the wooden restraint. To prevent the wooden restraint from failing due to the core material penetrating into the wooden restraint, we verify that the following formula (5) is satisfied.

[0093]

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[0094] In addition to examining the relationship between the compressive strength of the restraining plate and the stiffening force acting on it, it is also advisable to examine whether the short-term allowable compressive strength of the restraining plate is greater than the stiffening force acting when the core material yields (formula omitted).

[0095] 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]

[0096] 10: Core material 11a: Wide surface 11b:Narrow side 12: Wide section 12a: Bolt hole 13: Narrow section 14: Reinforcing rib 14a: Bolt hole 15: Protrusion 16: Spacer 16a: Bolt hole 17: Interpolation board 17a: Bolt hole 20, 20A, 20B, 20C, 20D, 20E: Wooden restraints 21: Restraint plate 21a: Side 21b: Bolt hole 22: Decorative board 23: Non-contact groove 24: Slit 25: Gap 29A: 1st hammer 29B:Second hammer 29C: Third hammer 29a: Joint 29b: Piercing part 31: Bolt 32: Washer 33: Nut 34: Washer 100: Buckling restrained brace G1, G2, G3, G4, G5: Gap A: Additional bending absorption area (boundary area) 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 member formed by a pair of wooden restraining plates arranged so as to face the two wide surfaces of the core material, and a plurality of first rivets arranged so as to face the two narrow surfaces of the core material and connecting the pair of restraining plates along their longitudinal direction, A buckling restraint brace, characterized in that the first rivets are arranged in a V-shape or an inverted V-shape along the longitudinal direction of the wooden restraint material, forming a rivet truss.

2. The clamp truss is formed on the center side of the wooden restraint material in the longitudinal direction, 2. The buckling restraint brace according to claim 1, wherein a plurality of second clamps extending perpendicular to the wide surface connect the ends of the pair of restraint plates to the end side of the wooden restraint material.

3. 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 restraint plate is provided with a slit at a position corresponding to the reinforcing rib so as not to interfere with the reinforcing rib, 3. The buckling restraint brace according to claim 2, wherein a plurality of third rivets are attached to the restraint plate so as to straddle the slits.

4. 4. The buckling restraint brace according to claim 2 or 3, wherein decorative plates are attached to the sides of the pair of restraint plates to conceal the first and second buckles.

5. The buckling restraint brace according to claim 3 or claim 4 dependent on claim 3, characterized in that the two piercing portions of each of the first rivet, the second rivet, and the third rivet are driven into and fixed to the restraint plate, or the two piercing portions of each of the first rivet, the second rivet, and the third rivet are inserted into fixing holes opened in the restraint plate and adhesively fixed.

6. a non-contact groove that does not come into contact with the wide surface of the core material is provided at an end of the restraint plate; 6. The buckling restraint brace according to claim 1, wherein the area of ​​the restraint plate other than the non-contact groove is in contact with the wide surface of the core material.

7. 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, 7. The buckling restraint brace according to claim 6, wherein the non-contact groove extends from an edge of the restraint plate to a position corresponding to the boundary between the wide portion and the narrow portion of the core material.

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