JP2023042165A - Buckling restraining brace - Google Patents

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, for example, at the time of a large earthquake, prevents the frame and the buckling restraining brace from deforming to the outside of a structure plane, a core material forming the buckling restraining brace from pressing a restraining plate forming a wooden restraining material, and a side plate pulled by the restraining plate from cracking.SOLUTION: A buckling restraining brace 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 pair of wooden side plates 22 arranged so as to face two narrow surfaces 11b included in the core material 10 and connected to the pair of restraining plates 21. The side plates 22 and the restraining plates 21 have an axial length shorter than that of the core material 10. The wooden restraining material 20 is provided with, in an end thereof, a pair of first steel materials 30A that are arranged outside of the pair of restraining plates 21 and tightened to each other with a bolt to restrain the pair of restraining plate 21.SELECTED DRAWING: Figure 3

Description

The present invention relates to buckling restraint braces.

BACKGROUND ART Conventionally, buckling restraint braces with anti-buckling measures have been applied as braces that form building structures (column/beam structures, roof structures, etc.). As a buckling restraint brace, there are a form in which a steel core is stiffened only with a steel plate, a form in which a steel core is stiffened with RC (Reinforced Concrete), and a steel core. There are various stiffening forms, such as a form covered with steel and mortar.

Incidentally, in recent years, attempts have been made to improve the fire resistance and earthquake resistance of wooden buildings (wooden houses, wooden warehouses, wooden stadiums, etc.). Wooden houses are inherently more flexible in terms of floor plan and design, the healing effect of natural timber, the humidity control effect of timber, and construction costs are generally lower than those of steel-frame or reinforced concrete structures, depending on the purpose of the building, such as a house. Although it has the advantage of being inexpensive, the above-mentioned improvement in fire resistance and earthquake resistance is one of the reasons why wooden buildings such as wooden houses are attracting attention. When the conventional buckling restraint braces described above are incorporated into the framework of such a wooden house, wooden columns and beams are mixed with the buckling restraint braces having stiffeners made of metal or concrete. , it cannot be denied that the appearance is unbalanced.

Therefore, it is conceivable to cover the entire buckling restraint brace with a panel made of wood or paper so that the stiffeners made of metal or concrete cannot be seen from the outside. There is concern about an increase in construction costs due to the labor involved in the work. In addition, conventional buckling restraint braces tend to be heavy due to the extensive use of metal, concrete, mortar, etc., and the weight of the light wooden beams and columns that make up a wooden house is The installation of buckling restraint braces is also structurally disproportionate.

Patent Literature 1 proposes a buckling restraint brace that is suitable for use by being incorporated in the framework of a wooden building such as a wooden house. Specifically, it is a buckling restraint brace having a core material and a pair of restraining materials arranged along both sides of the core material, the core material being made of steel and the pair of restraining materials being made of wood. A buckling restraint brace is obtained by applying laminated lumber to the restraining material, and the laminated lumber is laminated with lamina parallel to the core material.

Japanese Patent No. 4901491

The wooden restraining members surrounding the steel core forming the buckling restraint brace consist of a pair of restraining plates facing the two wide sides of the core and a pair of side plates connecting the ends of the pair of restraining plates. However, for buckling restraint braces, for example, when the frame and the buckling restraint brace incorporated in the frame are greatly deformed outside the structure plane during a major earthquake, the core material pushes the restraint plate and the core material There is a problem that the side plate is cracked when the restraint plate pushed into the side plate pulls the side plate. Patent Document 1 mentions a measure to prevent cracks in the side plates caused by the restraining plate pushed into the core material pulling the side plates when the buckling restraint brace is deformed outside the structural plane. There is no

The present invention has been made in view of the above problems, and is suitable for use by being incorporated into the framework of a wooden building. To provide a buckling restraint brace capable of eliminating the occurrence of cracks in a side plate pulled by the restraining plate when a core material forming the restraining brace pushes a restraining plate forming a wooden restraining member.

In order to achieve the above object, one aspect of the buckling restraint brace according to the present invention comprises:
A plate-like core material made of steel,
A pair of wooden restraint plates arranged to face the two wide surfaces of the core material, and a pair of wooden restraint plates arranged to face the two narrow surfaces of the core material. a pair of wooden side plates connected to and a wooden restraint formed by
the side plate and the restraint plate are shorter in axial length than the core member;
A pair of first steel members are provided at the ends of the wooden restraining member, which are arranged outside the pair of restraining plates and restrain the pair of restraining plates by being bolted to each other. It is characterized by

According to this aspect, at the ends of the wooden restraining member, the pair of first steel members are provided, which are disposed outside the pair of restraining plates and bolted to each other to restrain the pair of restraining plates. Cracks that may occur at the ends of the side plates connected near the ends of the pair of restraining plates that receive the strongest pushing force from the core material when the frame and the buckling restraint brace are deformed out of the structural plane. (cracking) can be suppressed.

In this aspect, a pair of restraining plates are connected to each other by a pair of side plates to form a wooden restraining member having a closed structure with four face members, and a steel core member is surrounded by the wooden restraining member. there is With this configuration, even when the buckling restraint brace of this aspect is applied to the framework of a wooden building, there is no risk of giving an appearance that is out of proportion with the framework constituent members. Here, the constraining plate and the side plate may be made of a solid material, or may be made of a laminated material laminated with lamina.

Furthermore, in this aspect, since the wooden restraining member has a structure in which the pair of side plates are connected to the pair of restraining plates, the wooden restraining member can be easily processed. For example, the buckling restraint brace described in Patent Document 1 is made by processing laminated lumber to produce two wooden restraint members having an L-shaped cross section, which are turned upside down and connected while sandwiching the core material. Processing is required. On the other hand, in the buckling restraint brace of this aspect, a wooden restraining member is manufactured by connecting a pair of side plates to a pair of restraining plates by gluing or the like with a core material disposed between the pair of restraining plates. By doing so, a buckling restraint brace can be fabricated. Therefore, the buckling restraint brace is made easier to manufacture.

In another aspect of the buckling restraint brace according to the invention,
The first steel material has a cross-sectional shape orthogonal to its longitudinal direction that is a hat shape including a central U-shaped portion and two overhanging portions projecting from both ends of the U-shaped portion,
The corresponding overhanging portions of the pair of first steel materials are in contact with each other, and a bolt is inserted through a bolt hole provided in both of the overhanging portions and bolted,
The pair of U-shaped portions constrains the ends of the pair of side plates from the outside.

According to this aspect, the first steel material having a hat-shaped cross section is applied, and the overhanging portions of the pair of first steel materials are brought into contact with each other and bolted to tighten the ends of the pair of restraining plates from the outside. can be constrained to In addition, since the U-shaped portions of the pair of first steel members constrain the ends of the pair of side plates from the outside, the effect of constraining the ends of the wooden restraining member is further enhanced.

In another aspect of the buckling restraint brace according to the invention,
The first steel material is formed of a flat steel, and a pair of the flat steel is bolted,
A pair of second steel materials formed of separate flat steel are connected to two narrow surfaces at the ends of the core material so as to be perpendicular to the wide surface,
The pair of second steel materials constrains the ends of the pair of side plates from the outside.

According to this aspect, the pair of first steel materials that constrain the ends of the pair of constraining plates from the outside and the pair of second steel materials that constrain the ends of the pair of side plates from the outside are both formed of flat steel. Therefore, the end portion of the wooden restraining member can be strongly restrained with a simple structure for reinforcing the end portion.

In another aspect of the buckling restraint brace according to the invention,
The first steel material is formed of a flat steel,
A pair of second steel materials sandwiching the core material and the wooden restraint material is disposed between the pair of flat steels, and the second steel material has a cross-sectional shape perpendicular to the longitudinal direction of the central web portion. and two orthogonal flange portions at both ends of the web portion, and
A bolt is inserted through a bolt hole provided in each of the pair of first steel materials and the two flange portions between them and bolted,
The pair of web portions constrains the ends of the pair of side plates from the outside.

According to this aspect, the first steel member made of a pair of flat steels that constrains the ends of the pair of constraining plates from the outside, and the pair of second steel members that have a U-shaped cross section and constrain the ends of the pair of side plates from the outside. Since the two steel materials are bolted to each other and integrated, the ends of the wooden restraining member can be strongly restrained by the closed structure of the steel materials of the first steel material and the second steel material.

In another aspect of the buckling restraint brace according to the invention,
The core material has a narrow portion in which the width of the wide surface is relatively narrow on the central side in the longitudinal direction, and a wide portion in which the width of the wide surface is relatively wide on the end portions in the longitudinal direction. has
The length of the side plate is set to be equal to or less than the length of the narrow portion of the core material.

According to this aspect, since the length of the side plate is set to be equal to or less than the length of the narrow portion of the core material, the end portion of the side plate comes into contact with the end portion of the wide portion of the core material. When the frame and the buckling restraint brace are deformed, it is possible to prevent the side plate from being pressed from the end of the wide portion of the core material and being damaged.

In another aspect of the buckling restraint brace according to the invention,
The edge of the side plate is provided with a concave portion that does not come into contact with the edge of the wide portion of the core member.

According to this aspect, since the end of the side plate is provided with a concave portion that does not come into contact with the end of the wide portion of the core member, the wide portion of the core member is deformed when the frame structure and the buckling restraint brace are deformed during an earthquake. Therefore, it is possible to reliably prevent the end of the wide portion from contacting the side plate, pressing the side plate, and damaging the side plate due to the pressing.

In another aspect of the buckling restraint brace according to the invention,
The narrow portion is provided with a plasticized region that is most easily plasticized in the core material,
The plasticized region is set inside the pair of first steel materials.

According to this aspect, since the plasticized region in the narrow portion of the core material is set inside the pair of first steel materials, even if the core material is buckled in the plasticized region, Since a pair of constraining plates are constrained by the pair of first steel materials on the outside thereof, the buckled region of the core material can be strongly constrained.

Since the boundary region between the wide-width portion and the narrow-width portion of the core material is a changing region in which the plane area and cross-sectional area of the core material change, the region on the narrow-width side of this changing region has plasticity that is likely to be plasticized. A zone is formed in which an additional bending moment acting on the core can be absorbed in this transition zone. Additional bending moment (or simply additional bending) is the bending moment that can act on wooden restraints due to large deformations of the frame and buckling restraint braces, for example during a major earthquake. . Thus, in this aspect, the additional bending moment acting on the core material can be effectively absorbed by the area on the narrow-width side of the boundary area between the wide-width part and the narrow-width part of the core material.

In addition, the core material may have two or more wide portions that increase in width in a multi-stage manner toward the end portion. For example, in a form having a two-stage wide portion, plasticization occurs in the area on the narrow side of the boundary area between the wide surface on the narrow side (relatively narrow wide portion) and the narrow portion. A region is formed.

In another aspect of the buckling restraint brace according to the invention,
Reinforcing ribs perpendicular to the wide surface are joined to the wide surface of the end portion of the core material in the longitudinal direction to form a cross-sectional shape,
The constraining plate is characterized in that recesses that do not interfere with the reinforcing ribs are provided at positions corresponding to the reinforcing ribs.

According to this aspect, at the ends of the core material in the longitudinal direction, reinforcing ribs perpendicular to the wide surface of the core material are joined to form a cross-shaped cross section. When the buckling restraint brace is attached to the gusset plate so that it is arranged parallel to the framing surface of the framing surface, the end of the core is reinforced by having stiffening ribs perpendicular to the wide plane parallel to the framing surface. , it is possible to increase the rigidity in the direction outside the structural plane. In the gusset plate of the structural surface to which the cross-sectional core material is attached in this way, the fin stiffener is attached to the gusset plate, and the core material and the gusset plate of the buckling restraint brace, and the reinforcing rib and the fin stiffener are spliced, respectively. It is joined by a high tension bolt or the like through a plate. In this aspect, recesses are provided at positions corresponding to the reinforcing ribs of the restraining plate, and the recesses prevent interference between the wooden restraining member and the reinforcing ribs.

Also, another aspect of the buckling restraint brace according to the present invention comprises:
In plan view, a gap is provided between the concave portion of the restraining plate and the reinforcing rib.

According to this aspect, the presence of the gap between the concave portion of the restraining plate and the reinforcing rib allows the gap to absorb the expansion and contraction of the core material when the core material expands and contracts according to the deformation of the structural surface. It is possible to solve the problem that the elastic core material comes into contact with the wall surface of the recess of the restraint plate and the wooden restraint material is damaged. Here, the setting of this gap is left to the discretion of the designer, and the expansion/contraction amount of the core material is calculated based on the set interlayer deformation angle. For example, the gap is set to be greater than or equal to the expansion/contraction amount of the core material. The "gap" here includes the gap between the longitudinal end portion of the recess and the reinforcing rib, as well as the gap between the side surface of the recess and the reinforcing rib.

Also, another aspect of the buckling restraint brace according to this aspect is:
An insertion plate is interposed between the wide surface of the core member and the restraint plate.

According to this aspect, due to high-order buckling deformation of the core material, a pressing force or the like is locally applied from the core material to the restraint plate, and damage to the restraint plate due to this local force is suppressed. can. By interposing the interposed plate between the wide surface of the core material and the restraining plate, the force acting from the convex portion during high-order buckling deformation of the core material is first transmitted to the interposed plate, and the transmitted force is transferred to the interposed plate. The force spread inside the insert plate and spread inside the insert plate will act on the wooden constraining plate. This effectively suppresses damage to the wooden restraint plate due to multiple localized forces acting from the core material.

As can be understood from the above description, according to the buckling restraint brace of the present invention, it is suitable for use by being incorporated in the framework of a wooden building or the like. It is possible to eliminate the fact that the core material forming the buckling restraining brace deforms out of plane and presses the restraining plate forming the wooden restraining member, and the side plate pulled by the restraining plate cracks.

1 is a perspective view of an example of a core material forming a buckling restraint brace according to the first embodiment; FIG. FIG. 2 is an exploded perspective view showing an example of a wooden restraining member forming the buckling restraint brace according to the first embodiment together with an example of a first steel material; 1 is a perspective view of an example of a buckling restraint brace according to a first embodiment; FIG. FIG. 11 is a perspective view of an example of a core material forming a buckling restraint brace according to a second embodiment; FIG. 11 is an exploded perspective view showing an example of a wooden restraining member forming the buckling restraint brace according to the second embodiment together with another example of the first steel material; FIG. 10 is a perspective view of an example of a buckling restraint brace according to a second embodiment; FIG. 11 is an exploded perspective view showing an example of a wooden restraint member forming a buckling restraint brace according to a third embodiment together with still another example of a first steel material; FIG. 11 is a perspective view of an example of a buckling restraint brace according to a third embodiment; It is a figure which shows the state which the buckling restraint brace which concerns on 1st Embodiment was incorporated in frame structures, such as a wooden building. FIG. 4 is a diagram for explaining the deformation mode of the frame during a large earthquake and the additional bending moment at the buckling restraint brace joint due to the deformation of the frame. FIG. 11 shows a global buckling line of a buckling restraint brace;

A buckling restraint brace according to each embodiment will be described below with reference to the accompanying drawings. In addition, in the present specification and drawings, substantially the same components may be denoted by the same reference numerals, thereby omitting duplicate descriptions.

[Buckling restraint brace according to the first embodiment]
First, an example of a buckling restraint brace according to a first embodiment will be described with reference to FIGS. 1 to 3. FIG. Here, FIG. 1 is a perspective view of an example of a core material forming the buckling restraint brace according to the first embodiment, and FIG. 2 is a wooden restraining material forming the buckling restraint brace according to the first embodiment. It is an exploded perspective view showing an example together with an example of the first steel material. FIG. 3 is a perspective view of an example of the buckling restraint brace according to the first embodiment.

As shown in FIG. 1, the core material 10 is formed of an elongated plate-shaped flat steel, and has a narrow portion 13 in which the width of the wide surface 11a is relatively narrow at the central side in the longitudinal direction, It has two steps of wide width portions 12A and 12B (the wide width portion 12B at the end portion is wider than the width of the wide width portion 12A) in which the width of the wide surface 11a is relatively wide at the end portion side in the longitudinal direction. there is Reinforcing ribs 14 orthogonal to the wide surface 11a are welded to the wide surface 11a of the core material 10 at the ends in the longitudinal direction to form a cross-shaped cross section.

Since the core material 10 has the narrow width portion 13 on the central side in the longitudinal direction and the wide width portion 12 on the end side in the longitudinal direction, the narrow width portion 13 on the central side is easily plasticized (plasticized region). A), and furthermore, the plasticized region A can be limited to the central narrow portion 13 .

In the core material 10, in the boundary area between the wide part 12A and the narrow part 13, the area on the side of the narrow part 13 is a changing area in which both the planar area and cross-sectional area of the core material 10 change and become smaller. , a plasticized region A, which is easily plasticized, is formed. In the illustrated example, the reinforcement ribs 14 are attached to the wide portion 12, and the rigidity of the wide portion 12 is further increased. easier to be An additional bending moment acting on the core 10 is effectively absorbed in this plasticized region A.

The total length t1 of the core member 10 is set longer than the total lengths t2 and t3 of the restraining plate 21 and the side plates 22 forming the wooden restraining member 20 described below.

Further, the wide portion 12 and the reinforcing ribs 14 are connected to the gusset plate provided on the structural surface and the fin stiffener (see FIG. 9) attached to the gusset plate via a splice plate, as described below. Bolt holes 12a and 14a are provided for bolting. When the buckling restraint brace 100 is attached to the gusset plate such that the wide surface 11a of the core member 10 is arranged parallel to the structural surface of the building, the core member 10 is perpendicular to the wide surface 11a parallel to the structural surface. By having the reinforcing ribs 14, the rigidity of the end portion of the core member 10 in the outward direction of the structural surface can be increased.

The core material 10 is preferably formed of a steel material having a low yield point such as an SN material (rolled steel material for building structure) or a LYP material (extremely low yield point steel material). Better absorbency.

A pair of second steel members 40A formed of flat steel are attached to the left and right narrow surfaces 11b of the relatively narrow wide portion 12A of the two-step wide portions 12A and 12B of the core member 10. are welded in a manner perpendicular to the wide surface 11a.

The pair of second steel members 40A form a closed structure of steel members together with a pair of first steel members 30A (see FIG. 2) described below to constrain the ends of the wooden restraining member 20. As shown in FIG.

The second steel member 40A extends from the narrow surface 11b of the wide portion 12A toward the narrow portion 13 of the core material 10, forming a gap G1 between the narrow surface 11b of the narrow portion 13 and the second steel member 40A. End portions of side plates 22 (see FIG. 2) of the wooden restraining member 20 described below are loosely fitted into the gaps G1.

As shown in FIG. 2, the wooden restraint member 20 has a pair of restraint plates 21 and a pair of side plates 22 connecting the pair of restraint plates 21, and the core member 10 is disposed between the pair of restraint plates 21. It is designed to be The total length t2 of the restraint plate 21 and the total length t3 of the side plate 22 have a relationship of t2>t3, and the total length t1 of the core member 10 is included, and a relationship of t1>t2>t3 is established.

The inner surfaces 21a of 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, and are bonded to the side surfaces 21b of the pair of restraint plates 21. A pair of wooden side plates 22 connected by an adhesive are arranged so as to face the two narrow sides 11b (see FIG. 1) of the core member 10. As shown in FIG. Here, the adhesive for connecting the constraining plate 21 and the side plate 22 includes urethane-based adhesive, epoxy-based adhesive, and the like. In addition to connecting the constraining plate 21 and the side plate 22 with an adhesive, a material to be driven or screwed, such as a wood screw, a wooden dowel, a screw, or a nail, extends from the side of the side plate 22 to the inside of the constraining plate 21 . By being hammered or screwed in, the restraining plate 21 and the side plate 22 are prevented from being separated at the joint interface in the event of a large earthquake or the like, and function as a fail-safe to enhance the effect of preventing the side plate 22 from splitting.

At both ends of the inner surface 21a of the constraining plate 21, the reinforcing ribs 14 provided at the ends of the core member 10 are arranged between the constraining plate 21 and the constraining plate 21 when the core member 10 is arranged between the pair of constraining plates 21. A recess 21c is provided to accommodate the reinforcing rib 14 so that it does not abut.

Although not shown, when the reinforcing ribs 14 are accommodated in the recesses 21c, the length of the reinforcing ribs 14 accommodated in the recesses 21c and the length of the recesses 21c are adjusted so that a predetermined gap is formed between the two. t4 is set. Since there is a gap between the reinforcing rib 14 and the concave portion 21c, when the buckling restraint brace incorporated in the frame is deformed during an earthquake, the reinforcing rib 14 contacts the concave portion 21c and presses the concave portion 21c. It is possible to prevent the constraining plate 21 from being damaged due to Moreover, it is desirable that a gap of a predetermined width is provided in both the width direction of the concave portion 21c and the reinforcing rib 14 as well.

Separate recesses 22 a are also provided at both ends of the side plate 22 . The concave portion 22a is provided at a position corresponding to the wide portion 12A of the core member 10 when the side plate 22 is arranged on the side of the narrow portion 13 of the core member 10. As shown in FIG.

When the end of the side plate 22 is loosely fitted in the gap G1 (see FIG. 1) between the second steel material 40A and the narrow surface 11b of the narrow portion 13, the end of the wide portion 12A and the side plate 22 are separated from each other. The ends abut without abutting or pressing against each other. In this state, when the buckling restraint brace is deformed during an earthquake, the end of the wide portion 12A presses the end of the side plate 22 and the side plate 22 may be damaged. is provided, even if the buckling restraint brace is deformed during an earthquake, for example, the end of the wide portion 12A is accommodated in the recess 22a, so that the side plate 22 is prevented from being damaged by pressure from the wide portion 12A. can be prevented.

The wooden restraining member 20 is manufactured by arranging the core member 10 between the pair of restraining plates 21 and then connecting the side surfaces 21b of the pair of restraining plates 21 and the pair of side plates 22 with an adhesive. , the wooden restraint member 20 is manufactured with the core member 10 sandwiched therebetween. Further, as described above, a fail-safe mechanism may be formed by further driving or screwing a plurality of wood screws, wood dowels, screws, nails, etc. from the side of the side plate 22 to the inside of the restraining plate 21. .

The constraining plate 21 and the side plate 22 may be made of solid wood or wood material including laminated wood laminated with lamina. As will be discussed in more detail below, the cross-sectional area, cross-sectional stiffness, Young's modulus, etc. of the wooden restraint 20 are set to prevent overall buckling of the buckling restraint brace. This Young's modulus is determined by the material of the wood. Examples of wood materials include Japanese cypress, red pine, larch, fir, spruce, and the like.

Corresponds to the ends of the pair of restraining plates 21 that receive the strongest pushing force from the core member 10 when the buckling restraining braces are deformed out of the structural plane during an earthquake in a state in which the restraining braces are incorporated in the frame. Cracks (splits) can occur at the ends of the side plates 22 that are connected to the position.

Therefore, as shown in FIG. 2, a pair of first steel members 30A are provided to constrain the ends of the pair of constraining plates 21 from the outside.

The first steel material 30A in the illustrated example is made of flat steel, and has a plurality of (three in the illustrated example) bolt holes 30a on the left and right sides. By aligning the pair of first steel members 30A outside the ends of the pair of restraining plates 21, inserting bolts 35 into the corresponding bolt holes 30a, and tightening with nuts 36, the pair of restraining plates 21 are It is strongly restrained from the outside by the pair of first steel members 30A. Here, although only one set of bolts and nuts is illustrated in FIG. 2, six sets of bolts and nuts corresponding to each bolt hole 30a are applied.

As shown in FIG. 3, the pair of first steel members 30A are engaged with the pair of second steel members 40A connected to the core member 10 incorporated in the wooden restraint member 20, and the pair of first steel members 30A are engaged. By tightening them together with a plurality of sets (six in the illustrated example) of bolts 35 and nuts 36, a closed structure of steel materials is formed by a pair of first steel materials 30A and a pair of second steel materials 40A. The end face of the second steel member 40A and the end face of the restraining plate 21 are, for example, flush with each other. abut. By tightening with the bolts 35 and nuts 36, the buckling restraint brace 100 is formed in which the pair of restraint plates 21 are restrained from the outside by the pair of first steel members 30A.

According to the buckling restraint brace 100, a pair of restraint plates 21 are connected to each other by a pair of side plates 22 to form a wooden restraint member 20 having a closed structure with four face members, and a steel core member 10. It is surrounded by wooden restraints 20 . With this configuration, even when the buckling restraint brace 100 is applied to the frame of a wooden building, there is no risk of giving it an appearance that is out of proportion to the frame components.

Furthermore, at the ends of the wooden restraining member 20, a pair of first steel members 30A are provided, which are arranged outside the pair of restraining plates 21 and bolted to each other to restrain the pair of restraining plates 21. Therefore, when the frame and the buckling restraint brace 100 are deformed out of the structural plane, the ends of the side plates 22 connected to the vicinity of the ends of the pair of restraint plates 21 receive the strongest pushing force from the core member 10. It is possible to suppress cracks that may occur in the

[Buckling restraint brace according to the second embodiment]
Next, an example of a buckling restraint brace according to a second embodiment will be described with reference to FIGS. 4 to 6. FIG. Here, FIG. 4 is a perspective view of an example of a core material forming the buckling restraint brace according to the second embodiment, and FIG. 5 is a wooden restraining material forming the buckling restraint brace according to the second embodiment. 2 is an exploded perspective view showing an example of 1 together with another example of the first steel material. FIG. FIG. 6 is a perspective view of an example of the buckling restraint brace according to the second embodiment.

A core member 10A shown in FIG. 4 is different from the core member 10 shown in FIG. 1 in that the pair of second steel members 40A is not provided.

As shown in FIG. 5, with respect to the steel material for restraining the ends of the wooden restraining member 20, the pair of first steel materials 30A for restraining the pair of restraining plates 21 from the outside is the same as the first steel material shown in FIGS. is. On the other hand, the second steel material 40B is a steel material having a central web portion 41 and two orthogonal flange portions 42 at both ends of the web portion 41, and having a U-shaped cross section.

Bolts 35 are inserted through the bolt holes 30a of the pair of first steel members 30A and the bolt holes 42a of the two flange portions 42 of the second steel member 40B between them, and are tightened with nuts 36, whereby the pair of The restraint plate 21 is strongly restrained from the outside by the pair of first steel members 30A.

Although not shown, the web portion 41 of the second steel member 40B may be welded to the narrow surface 11b of the wide portion 12A of the core member 10 like the second steel member 40A in FIG. .

As shown in FIG. 6, at both ends of the wooden restraint member 20, a pair of first steel members 30A and a pair of second steel members 40B are formed to form a closed structure of steel members, so that the pair of restraint plates 21 are separated from the outside thereof. A buckling restraint brace 100A restrained by a pair of first steel members 30A is formed.

The buckling restraint brace 100A also provides the same effect as the buckling restraint brace 100. FIG.

[Buckling restraint brace according to the third embodiment]
Next, an example of a buckling restraint brace according to a third embodiment will be described with reference to FIGS. 7 and 8. FIG. Here, FIG. 7 is an exploded perspective view showing an example of a wooden restraining member forming the buckling restraining brace according to the third embodiment together with still another example of the first steel material. FIG. 8 is a perspective view of an example of a buckling restraint brace according to the third embodiment.

In this embodiment, the same core material 10A as in the second embodiment is applied.

As shown in FIG. 7, the steel members that constrain the ends of the wooden restraining member 20 are a pair of first steel members 30B, which include a central U-shaped portion 31 and two overhangs projecting from both ends of the U-shaped portion 31. The steel material has a portion 32 and has a hat-shaped cross section.

The corresponding overhanging portions 32 of the pair of first steel members 30B are brought into contact with each other, and the bolts 35 are inserted through the bolt holes 32a of the both overhanging portions 32 and tightened with the nuts 36, thereby forming the pair of restraining plates 21. are firmly restrained from the outside by the pair of first steel materials 30B.

As shown in FIG. 8, at both ends of the wooden restraining member 20, a pair of first steel members 30B form a closed structure of steel members, so that the pair of restraining plates 21 are secured from the outside by the pair of first steel members 30B. A constrained buckling restraint brace 100B is formed.

The buckling restraint brace 100B also has the same effect as the buckling restraint braces 100 and 100A.

Here, although not shown, in the buckling restraint braces 100, 100A, and 100B, an insert plate may be interposed between the wide surface 11a of the core member 10 and the inner surface 21a of the restraint plate 21. Either a steel plate or a wooden plate may be applied to the insertion plate, and LVL (Laminated Veneer Lumber), for example, may be applied as the wooden plate.

Due to high-order buckling deformation of the core material 10, a pressing force acts locally on the inner surface 21a of the restraining plate 21 from the core material 10, and the restraining plate 21 may be damaged due to this local pressing force. be. On the other hand, since the interposed plate is interposed between the core member 10 and the restraint plate 21, the pressing force acting from the convex portion during high-order buckling deformation of the core member 10 is , the transmitted pressing force spreads inside the inserting plate, and the pressing force diffused inside the inserting plate acts on the wooden restraining plate 21 as a distributed force. This effectively suppresses damage to the wooden restraining plate 21 due to multiple local pressing forces acting from the core material 10 .

[Frame structure incorporating buckling restraint braces]
Next, an example of a building frame incorporating the buckling restraint brace of the first embodiment will be described with reference to FIGS. 9 and 10. FIG. Here, FIG. 9 is a diagram showing a state in which the buckling restraint brace according to the first embodiment is incorporated in a frame structure such as a wooden building. FIG. 10 is a diagram for explaining the deformation mode of the frame during a large earthquake and the additional bending moment at the buckling restraint brace joint due to the deformation of the frame. In addition, the buckling restraint brace shown in the figure is incorporated into the framework of S (Steel) buildings, the framework of RC buildings, and the framework of SRC (Steel Reinforced Concrete) buildings in addition to the framework of wooden buildings. may be

A frame S shown in FIG. 9 is formed by wooden pillars C and beams B that constitute a wooden building or the like. A gusset plate GP made of flat steel is attached to the two diagonal corners. A fin stiffener FS is welded to the surface of the gusset plate GP so as to be perpendicular to the surface. The fin stiffener FS is joined to the gusset plate GP so that the core L3 of the fin stiffener FS intersects the intersection point O of 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 in a line passing through both intersections O at diagonal positions.

The gusset plate GP and the wide portion 12 of the core member 10 are joined with high-tension bolts via the splice plate SP, and the fin stiffener FS and the reinforcing ribs 14 are joined with high-tension bolts via the splice plate SP.

As shown in Fig. 10, due to the deformation of the structural surface during a large earthquake, the additional bending moment shown in the following formula (1) is generated at the buckling restraint brace joint when the joint is regarded as rigid. can work.

According to the buckling restraint brace 100, the ends of the restraint plate 21 that can receive the strongest pushing force from the core material 10 are surrounded by the closed structure of the pair of first steel members 30A and the pair of second steel members 40B, Since the pair of restraint plates 21 are restrained from the outside by the pair of first steel members 30A, when the structural surface S to which the buckling restraint braces 100 are attached is greatly deformed during a large earthquake, It is possible to suppress cracks that may occur at the ends of the side plates 22 connected near the ends of the pair of restraint plates 21 that receive the strongest pushing force.

[Study of global buckling]
Next, a design method for preventing global buckling of the buckling restraint brace will be described.

The buckling restraint brace is designed so that the following formula (2) is satisfied so that the entire buckling restraint brace does not buckle.

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

The condition for preventing the overall buckling of the wooden restraint member satisfies the following equation (4).

Equation (4) is shown in FIG. 11 as the overall buckling line of the buckling restraint brace. In Fig. 11, the upper side of the whole seat bending line is the safe area, and the lower side is the dangerous area. , and the yield flexural capacity of the wooden restraint is set. The overall buckling line of the buckling restraint brace shown in FIG. 11 applies to both the overall buckling of the core material in the direction of the weak axis and the overall buckling of the core material in the direction of the strong axis.

In addition to examining the relationship between the yield bending strength of the wooden restraining material and the bending moment acting on it, it is also possible that the short-term allowable bending strength of the wooden restraining material is greater than the bending moment that acts when the core material yields. It is better to check them together (numerical formulas are omitted).

<Examination of penetration failure of wooden restraint>
Next, we will explain how to examine the failure of wooden restraints due to embedment. In order to prevent the wooden restraining material from breaking due to the core material sinking into the wooden restraining material, it is verified that the following equation (5) is satisfied.

Here, in addition to verifying the relationship between the above-mentioned immersion resistance of the restraint plate and the stiffening force acting, it is also necessary to confirm that the short-term allowable immersion resistance of the restraint plate is greater than the stiffening force acting when the core material yields. (Formulas omitted).

It should be noted that other embodiments may be possible in which other components are combined with the configurations described in the above embodiments, and the present invention is not limited to the configurations shown here. Regarding this point, it is possible to change without departing from the gist of the present invention, and it can be determined appropriately according to the application form.

10, 10A: core material 11a: wide surface 11b: narrow surface 12, 12A, 12B: wide width part 12a: bolt hole 13: narrow width part 14: reinforcing rib 14a: bolt hole 15: second steel plate 15A: second steel plate ( flat steel)
17: Insertion plate 17a: Bolt hole 20: Wooden restraint member 21: Restraint plate 21a: Inner surface 21b: Side surface 21c: Recessed portion 22: Side plate 22a: Recessed portion 30: First steel material 30A: First steel material (flat steel)
30B: First steel material 30a: Bolt hole 31: U-shaped part 32: Overhang part 32a: Bolt hole 35: Bolt 36: Nut 40: Second steel material 40A: Second steel material (flat steel)
40B: Second steel material 41: Web portion 42: Flange portion 42a: Bolt hole 100, 100A, 100B: Buckling restraint brace A: Plasticized region S: Frame (structural surface)
C: Column B: Beam GP: Gusset plate FS: Fin stiffener SP: Splice plate

Claims (8)

A plate-like core material made of steel,
A pair of wooden restraint plates arranged to face the two wide surfaces of the core material, and a pair of wooden restraint plates arranged to face the two narrow surfaces of the core material. a pair of wooden side plates connected to and a wooden restraint formed by
the side plate and the restraint plate are shorter in axial length than the core member;
A pair of first steel members are provided at the ends of the wooden restraining member, which are arranged outside the pair of restraining plates and restrain the pair of restraining plates by being bolted to each other. A buckling restraint brace, characterized by: The first steel material has a cross-sectional shape orthogonal to its longitudinal direction that is a hat shape including a central U-shaped portion and two overhanging portions projecting from both ends of the U-shaped portion,
The corresponding overhanging portions of the pair of first steel materials are in contact with each other, and a bolt is inserted through a bolt hole provided in both of the overhanging portions and bolted,
The buckling restraint brace according to claim 1, wherein the pair of U-shaped portions restrains the ends of the pair of side plates from the outside. The first steel material is formed of a flat steel, and a pair of the flat steel is bolted,
A pair of second steel materials formed of separate flat steel are connected to two narrow surfaces at the ends of the core material so as to be perpendicular to the wide surface,
2. The buckling restraint brace according to claim 1, wherein the pair of second steel members restrains the ends of the pair of side plates from the outside. The first steel material is formed of a flat steel,
A pair of second steel materials sandwiching the core material and the wooden restraint material is disposed between the pair of flat steels, and the second steel material has a cross-sectional shape perpendicular to the longitudinal direction of the central web portion. and two orthogonal flange portions at both ends of the web portion, and
A bolt is inserted through a bolt hole provided in each of the pair of first steel materials and the two flange portions between them and bolted,
2. A buckling restrained brace according to claim 1, wherein said pair of web portions externally restrains the ends of said pair of side plates. The core material has a narrow portion in which the width of the wide surface is relatively narrow on the central side in the longitudinal direction, and a wide portion in which the width of the wide surface is relatively wide on the end portions in the longitudinal direction. has
The buckling restraint brace according to any one of claims 1 to 4, wherein the length of the side plate is set to be equal to or less than the length of the narrow portion of the core member. 6. The buckling restraint brace according to claim 5, wherein the end of the side plate is provided with a recess that does not come into contact with the end of the wide portion of the core. The narrow portion is provided with a plasticized region that is most easily plasticized in the core material,
The buckling restraint brace according to claim 5 or 6, wherein the plasticized region is set inside the pair of first steel members. Reinforcing ribs perpendicular to the wide surface are joined to the wide surface of the end portion of the core material in the longitudinal direction to form a cross-sectional shape,
The buckling restraint brace according to any one of claims 1 to 7, characterized in that a concave portion that does not interfere with the reinforcing rib is provided in the restraining plate at a position corresponding to the reinforcing rib. .

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