JP2020183701A - Buckling restraint brace - Google Patents

Abstract

To provide a buckling restraint brace suitable to be used assembled into a frame of a wooden building and capable of solving the problem in which the frame deforms significantly for example in a large earthquake and a so-called additional flexure moment acts on a wooden restraint material and get broken.SOLUTION: The buckling restraint brace 100 having a core material 10 in steel and a wooden restraint material 20 formed by a pair of restraint plates 21 and a pair of side plates 22 made of wood is provided, the core material 10 has a narrow width part 13 and a wide width part 12 and has a gap G1 between a side surface of the wide width part 12 and the side plate 22, in the pair of the restraint plate 21 a first bolt hole 21a is drilled to form a first bolt hole unit, in the first bolt hole unit a first length bolt 31 is inserted and fastened by a nut, in the pair of the side plates 22 and the restraint plate 21, a second bolt hole 22a is drilled to form a second bolt hole unit and in the second bolt hole unit a second length bolt 41 is inserted and fastened by a nut.SELECTED DRAWING: Figure 3

Description

The present invention relates to a buckling restraint brace.

Conventionally, a buckling restraint brace with buckling prevention measures has been applied as a brace for forming a building frame (column / beam frame, roof frame, etc.). The buckling restraint brace has a form in which the circumference of the steel core material is stiffened only with a steel plate, a form in which the circumference of the steel core material is stiffened with RC (Reinforced Concrete), and a steel core material. There are various stiffening forms such as a form in which the periphery is covered with steel and mortar.

By the way, in recent years, the fire resistance and earthquake resistance of wooden buildings (wooden houses, wooden warehouses, wooden stadiums, etc.) have been improved. By nature, wooden houses have a high degree of freedom in layout and design, the healing effect of natural wood, the humidity control effect of wood, and depending on the building application such as housing, the construction cost is generally higher than that of steel or RC structures. Although it has the advantage of being inexpensive, the above-mentioned improvement in fire resistance and earthquake resistance is one of the factors that are increasing the attention of wooden buildings such as wooden houses. When the above-mentioned conventional buckling restraint brace is incorporated in the frame of such a wooden house, wooden columns and beams and a buckling restraint brace having a metal or concrete stiffener are mixed. It is undeniable that the appearance will be disproportionate.

Therefore, it is conceivable to cover the entire buckling restraint brace with a wooden or paper panel or the like so that the stiffener made of metal or concrete cannot be seen from the outside. There is concern that the construction cost will increase due to the labor required. In addition, conventional buckling restraint braces tend to be heavy because metal, concrete, mortar, etc. are often used, and they are heavy in the lightweight wooden beams and columns that make up a wooden house. Installing a buckling restraint brace is also structurally disproportionate.

Therefore, a buckling restraint brace suitable for use by incorporating it into the frame of a wooden building such as a wooden house has been proposed. Specifically, it is a buckling restraint brace having a core material and a pair of restraint materials arranged along both sides of the core material. The core material is formed of a steel material, and a pair of restraint materials are formed of wood. However, a buckling restraint brace is obtained by applying a laminated lumber to this restraining material and assuming that the laminated lumber is laminated with lamina in parallel with the core material (see, for example, Patent Document 1).

Japanese Patent No. 4901491

A buckling restraint brace in which a steel core is surrounded by a wooden restraint, for example, when the frame is significantly deformed during a large earthquake, the so-called additional bending moment (or simply) caused by this deformation. , Additional bending) can act on the restraint. When this additional bending moment acts on the wooden restraint, the restraint may be damaged. Then, when the restraining material is damaged, the buckling restraining function of the core material by the restraining material is lowered, and the core material may be buckled. Patent Document 1 does not mention measures for preventing such a so-called additional bending moment from acting on the restraining material.

The present invention has been made in view of the above problems, and is suitable for use by incorporating it into a frame of a wooden building or the like. For example, the frame is greatly deformed during a large earthquake, and a so-called additional bending moment is a wooden restraint material. It is intended to provide a buckling restraint brace that can act on and eliminate damage.

In order to achieve the above object, one aspect of the buckling restraint brace according to the present invention is:
With a steel plate-shaped core material,
A pair of wooden restraint plates arranged so as to face the two wide surfaces of the core material, and the pair of restraint plates arranged so as to face the two narrow surfaces of the core material. With a pair of wooden side plates connected to, and a wooden restraint formed by,
A first bolt hole is formed at a corresponding position of the pair of restraint plates, a first bolt hole unit is formed by the corresponding first bolt hole, and a first long bolt is formed in each of the plurality of first bolt hole units. Is inserted and the nut is tightened,
A second bolt hole is formed at a position corresponding to the pair of side plates and the restraint plate, a second bolt hole unit is formed by the corresponding second bolt hole, and a second bolt hole unit is formed in each of the plurality of second bolt hole units. It is characterized in that a double bolt is inserted and a nut is tightened.

According to this aspect, a pair of restraint plates are joined by nut-tightening a plurality of first length bolts, and a pair of side plates are joined by nut-tightening a plurality of second length bolts together with a restraint plate in between. Therefore, it is possible to form a wooden restraint material having a high restraint between the pair of restraint plates and the pair of side plates. This makes it possible to form a buckling restraint brace having a highly rigid wooden restraint that is less likely to be damaged by the applied bending moment.

Further, in this embodiment, the pair of restraint plates are connected to each other by a pair of side plates to form a wooden restraint material having a closed structure with four face materials, and the steel core material is surrounded by the wooden restraint material. Has been done. With this configuration, even when the buckling restraint brace of this embodiment is applied to the frame of a wooden building, there is no risk of giving an appearance disproportionate to the frame components. Here, the wooden restraint material and the side plate may be formed of solid wood or laminated wood in which lamina is laminated.

Further, in this embodiment, since the wooden restraint has a structure in which the pair of side plates are connected to the pair of restraint plates, the wooden restraint can be easily processed. For example, in the buckling restraint brace described in Patent Document 1, two restraining materials having an L-shaped cross section are produced by processing laminated wood, and these are turned upside down and connected with a core material sandwiched between them. Needs. On the other hand, in the buckling restraint brace of this embodiment, a pair of side plates are connected to the pair of restraint plates to manufacture a wooden restraint material, and for example, a core material is inserted into the hollow of the wooden restraint material. The buckling restraint brace can be manufactured. Therefore, the buckling restraint brace can be manufactured more easily.

Another aspect of the buckling restraint brace according to the present invention is characterized in that the contact surface between the restraint plate and the side plate is joined by an adhesive and fastened by the second long bolt.

According to this aspect, the contact surface between the restraint plate and the side plate is joined by an adhesive and further tightened by a second long bolt, so that the adhesive surface which is the contact surface between the restraint plate and the side plate has a second length. It is possible to form a buckling restraint brace having a wooden restraint that is crimped with bolts and has a higher connection strength between the restraint plate and the side plate.

Further, in another aspect of the buckling restraint brace according to the present invention, a reinforcing rib orthogonal to the wide surface is joined to the wide surface at the longitudinal end of the core material to form a cross section. ,
The wooden restraining material is characterized in that a slit that does not interfere with the reinforcing rib is provided at a position corresponding to the reinforcing rib.

According to this aspect, at the end portion in the longitudinal direction of the core material, the wide surface of the core material is a building because the reinforcing ribs orthogonal to the wide surface of the core material are joined to form a cross section. When the buckling restraint brace is attached to the gusset plate so that it is arranged parallel to the construction surface, the core material has reinforcing ribs orthogonal to the wide surface parallel to the construction surface, so that the end portion of the core material In, the rigidity in the out-of-structure direction can be increased. In the gusset plate of the structure to which the cross-section core material is attached in this way, the fin stiffener is attached to the gusset plate, and the core material and gusset plate of the buckling restraint brace, the reinforcing rib and the fin stiffener are spliced respectively. It is joined with a high tension bolt or the like via a plate. In this embodiment, a slit is provided at a position corresponding to the reinforcing rib of the wooden restraint material, and the slit is configured so that the wooden restraint material and the reinforcing rib do not interfere with each other.

In addition, another aspect of the buckling restraint brace according to the present invention is characterized in that a gap is provided between the slit and the reinforcing rib in a plan view.

According to this aspect, since there is a gap between the slit and the reinforcing rib, when the core material expands and contracts according to the deformation of the structure surface, the gap can absorb the expansion and contraction of the core material. It is possible to solve the problem that the stretchable core material comes into contact with the wall surface of the slit and the wooden restraint material is damaged. Here, the setting of this gap is also 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 equal to or larger than the expansion / contraction amount of the core material. The "gap" here includes the gap between the longitudinal end of the slit and the reinforcing rib, as well as the gap between the side surface of the slit and the reinforcing rib, and is between the side surface of the slit and the reinforcing rib. As the gap, the same gap as the gap between the side surface of the wide portion of the core material and the side plate can be set.

In addition, another aspect of the buckling restraint brace according to this aspect is characterized in that an interpolation plate is interposed between the wide surface of the core material and the restraint plate.

According to this aspect, a compressive force or the like is locally applied from the core material to the restraint plate due to the higher-order buckling deformation of the core material, and the restraint plate is prevented from being damaged due to this local force. can do. By interpolating the interpolation plate between the wide surface of the core material and the restraining plate, the force acting from the convex portion of the higher-order buckling deformation of the core material is first transmitted to the interpolation plate, and the transmitted force is interpolated. The force that spreads in the board and diffuses in the interpolation board acts on the wooden restraint board. As a result, damage to the wooden restraint plate due to a plurality of local forces acting from the core material is effectively suppressed.

As can be understood from the above description, the buckling restraint brace of the present invention is suitable for use by incorporating it into a frame of a wooden building or the like. For example, the frame is greatly deformed during a large earthquake, so-called addition. It is possible to eliminate the bending moment acting on the wooden restraint and damaging it.

It is a perspective view which shows an example of the core material which forms the buckling restraint brace which concerns on 1st Embodiment together with a spacer. It is a perspective view of an example of the wooden restraint material which forms the buckling restraint brace which concerns on 1st Embodiment. It is a perspective view of an example of a buckling restraint brace according to 1st Embodiment. FIG. 3 is an arrow view in the IV direction of FIG. It is a V-direction arrow view of FIG. It is a VI-VI arrow view of FIG. It is a figure which shows the state which the buckling restraint brace which concerns on 1st Embodiment is incorporated in the frame of a wooden building or the like. It is a figure explaining the deformation mode of the frame at the time of a big earthquake, and the additional bending moment at the buckling restraint brace joint due to the deformation of the frame. It is a perspective view which shows an example of the core material which forms the buckling restraint brace which concerns on 2nd Embodiment together with a spacer. It is a vertical sectional view of an example of a buckling restraint brace which concerns on 2nd Embodiment. It is an enlarged view of the XI part of FIG. 10, and is the figure explaining that the force acting locally from the convex part of the surface of a core material is diffused through an interpolation plate and is transmitted to a restraint plate. It is a figure which shows the whole buckling bending line of a buckling restraint brace.

Hereinafter, the buckling restraint brace according to each embodiment will be described with reference to the attached drawings. In the present specification and the drawings, substantially the same components may be designated by the same reference numerals to omit duplicate explanations.

[Buckling restraint brace according to the first embodiment]
<Core material>
First, an example of a core material forming a buckling restraint brace according to the first embodiment will be described with reference to FIG. Here, FIG. 1 is a perspective view showing an example of a core material forming a buckling restraint brace according to the first embodiment together with a spacer.

The core material 10 is formed of elongated, plate-shaped flat steel, and has a narrow portion 13 having a relatively narrow width of the wide surface 11a on the central side in the longitudinal direction thereof, and the end side in the longitudinal direction thereof. Has a wide portion 12 in which the width of the wide surface 11a is relatively wide. Further, a reinforcing rib 14 orthogonal to the wide surface 11a is joined by welding to the wide surface 11a at the end portion of the core member 10 in the longitudinal direction to form a cross section.

The core material 10 has a narrow portion 13 on the central side in the longitudinal direction and a wide portion 12 on the end side in the longitudinal direction, so that the narrow portion 13 on the central side can be easily plasticized. Further, the plasticized region can be limited to the narrow portion 13 on the central side.

Further, as described below, the wide portion 12 and the reinforcing rib 14 are connected to a gusset plate provided on the structure surface and a fin stiffener (see FIG. 7) attached to the gusset plate via a splice plate, respectively. Bolt holes 12a and 14a for bolting are provided. When the buckling restraint brace 100 is attached to the gusset plate so that the wide surface 11a of the core material 10 is arranged parallel to the structure surface of the building, the core material 10 is orthogonal to the wide surface 11a parallel to the structure surface. By having the reinforcing rib 14, it is possible to increase the rigidity in the out-of-structure direction at the end portion of the core material 10.

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 (ultra-low yield point steel material), and the seismic energy due to the yield of the core material 10 Good absorbency.

At the center position of the narrow width portion 13 of the core material 10, a columnar protrusion 15 made of steel projects from the left and right side surfaces of the narrow width portion 13 (an example of the peripheral surface of the narrow width portion 13). The protrusion 15 is joined to the side surface of the narrow portion 13 by welding or the like. The protrusion 15 engages with an engagement hole provided in a wooden restraint (see FIG. 2) described below. The protrusion 15 may project from the upper and lower planes of the narrow portion 13, and in this case, an engaging hole is opened at a corresponding position of the restraint plate 21 in the wooden restraint material (see FIG. 2). The protrusion 15 is engaged with the protrusion 15.

The core material 10 is provided with elongated square columnar spacers 16 arranged in the X1 direction with respect to the left and right sides of the narrow width portion 13, and spacers 16 are arranged on the left and right sides of the narrow width portion 13. Is housed inside the wooden restraint shown below. The spacer 16 may be either a steel member or a wooden member. Further, the spacer 16 may have a form other than the illustrated example, such as a columnar shape. A plurality of bolt holes 16a (three in the illustrated example) through which the first long bolts shown below are inserted are provided in the spacer 16 at intervals in the longitudinal direction thereof.

<Wooden restraint>
Next, an example of the wooden restraint material forming the buckling restraint brace according to the first embodiment will be described with reference to FIG. Here, FIG. 2 is a perspective view of an example of a wooden restraint material forming the buckling restraint brace according to the first embodiment.

The wooden restraint 20 has a pair of restraint plates 21 and a pair of side plates 22 connecting the pair of restraint plates 21, so that the core material 10 is arranged in the gap 25 between the pair of restraint plates 21. It has become. 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 the pair of wooden restraint plates 21 are connected to the pair of restraint plates 21. The 22 is arranged so as to face the two narrow surfaces 11b (see FIG. 1) of the core material 10.

First bolt holes 21a having counterbore are formed at corresponding positions of the pair of restraint plates 21, and the first bolt hole unit 21b is formed by the two corresponding first bolt holes 21a. In the illustrated example, two first bolt hole units 21b are provided in the width direction of the restraint plate 21, and six are provided in the longitudinal direction of the restraint plate 21, so that there are a total of twelve first bolt hole units 21b.

Then, when the core material 10 is arranged in the gap 25 between the pair of restraint plates 21, each bolt hole 16a provided in the spacer 16 is positioned at a position corresponding to each first bolt hole unit 21b. The bolt hole 16a also forms the first bolt hole unit 21b. The first long bolt 31 is inserted into the first bolt hole unit 21b and tightened with a nut 33. More specifically, a washer 32 is arranged in the counterbore of one of the first bolt holes 21a forming the first bolt hole unit 21b, and the first long bolt 31 is transferred to the first bolt hole unit 21b via the washer 32. A washer 34 is arranged in the counterbore of the other first bolt hole 21a, and the nut 33 is tightened in the screw groove at the tip of the first long bolt 31 protruding outward from the washer 34. ..

On the other hand, second bolt holes 22a and 21c are formed at corresponding positions of the pair of side plates 22 and the restraint plate 21, respectively, and the second bolt hole unit 22b is formed by the corresponding second bolt holes 22a and 21c. ing. The second bolt hole unit 22b is provided at a position that does not interfere with the first bolt hole unit 21b. In the illustrated example, two are provided in the width direction of the side plate 22, and seven are provided in the longitudinal direction of the side plate 22. , There are a total of 14 second bolt hole units 21b.

Then, a second long bolt 41 is inserted into each second bolt hole unit 22b and tightened with a nut 43. More specifically, a washer 42 is arranged in the counterbore of one of the second bolt holes 22a forming the second bolt hole unit 22b, and the second long bolt 41 is transferred to the second bolt hole unit 22b via the washer 42. A washer 44 is arranged in the counterbore of the other second bolt hole 22a, and the nut 43 is tightened in the screw groove at the tip of the second long bolt 41 protruding outward from the washer 44.

Further, when the second long bolt 41 is tightened with the nut 43, an adhesive is applied to the contact surface between the restraint plate 21 and the side plate 22, and the second long bolt 41 is attached to the nut 43 before the adhesive is cured. The process of tightening is performed.

Here, the adhesive includes a urethane-based adhesive, an epoxy-based adhesive, and the like. After applying the adhesive to the contact surfaces of the restraint plate 21 and the side plate 22, the second length is before the adhesive is cured. It is preferable to apply a urethane-based adhesive that requires a certain amount of time to cure (for example, about 24 hours) so that the bolt 41 can be tightened with the nut 43. The adhesive surface formed by curing the adhesive is firmly crimped by the tightening force of the second long bolt 41 tightened by the nut 43.

In this way, the pair of restraint plates 21 are restrained by tightening the plurality of first length bolts 31 with the nuts 33, and the pair of side plates 22 and the restraint plate 21 are restrained via the adhesive surface of the second length bolt 41. By tightening with a nut 43, a wooden restraining member 20 having a closed structure is formed in which the restraining plate 21 and the side plate 22 are firmly joined.

The left and right side plates 22 are provided with engaging holes 22c at which the protrusions 15 of the core member 10 are engaged at the central positions in the longitudinal direction thereof. When the protrusion 15 of the core material 10 engages with the engaging hole 22c provided in the wooden restraint material 20, the core material 10 inserted into the wooden restraint material 20 is one of the wooden restraint materials 20. It is possible to prevent bias toward the end. Therefore, when the core material 10 is biased to one end of the wooden restraint 20 in this way, there is a problem that the other end of the wooden restraint 20 in which the core 10 does not exist becomes a weak part in terms of strength. Does not occur.

Further, the spacer 16 has a bolt hole 16a constituting the first bolt hole unit 21b, and the first long bolt 31 is also inserted through the bolt hole 16a, so that the spacer 16 is oriented in the longitudinal direction of the core material 10. Movement is deterred. Hereinafter, as will be described with reference to FIG. 7, since the buckling restraint brace is generally arranged diagonally on the structure surface, the spacer 16 can easily move diagonally downward, and the movement of the spacer 16 causes the spacer 16 to move diagonally upward. A large gap is likely to occur between the end of the spacer 16 and the wide portion 12 of the core material 10. Therefore, in the buckling restraint brace, the diagonally upper region where the spacer 16 does not exist tends to be a weak part in terms of strength, but as shown in the figure, the first long bolt 31 is inserted into the bolt hole 16a of the spacer 16. , Such movement of the spacer 16 is eliminated, and a weak part in strength due to the movement of the spacer 16 does not occur.

The restraint plate 21 and the side plate 22 may be formed of either a solid wood or a wood-based material including laminated wood in which lamina is laminated. As will be described in detail below, the cross-sectional area, cross-sectional rigidity, Young's modulus, etc. of the wooden restraint member 20 are set so as to prevent the entire buckling restraint brace from buckling. And this Young's modulus is determined by the material of wood. Examples of the material of wood include cypress, Japanese red pine, larch, fir, spruce and the like.

A slit 24 that does not interfere with the reinforcing rib 14 is provided at a position corresponding to the reinforcing rib 14 when the core material 10 is accommodated in the gap 25 in the end portion of the restraining plate 21.

<Buckling restraint brace>
Next, with reference to FIGS. 3 to 6, an example of a buckling restraint brace according to the first embodiment, which is formed of the core member 10 and the wooden restraint member 20 described so far, will be described. Here, FIG. 3 is a perspective view of an example of the buckling restraint brace according to the first embodiment, and FIGS. 4, 5, and 6 are an arrow view in the IV direction and an arrow view in the V direction of FIG. 3, respectively. It is a figure and a VI-VI arrow view.

In the buckling restraint brace 100, a wooden restraint 20 is arranged so as to surround a part of the narrow portion 13 and the wide portion 12 of the core material 10, and the cross-shaped portion at the end of the wide portion 12 is a wooden restraint. The whole is configured so as to project from the end portion of the material 20, and the bolt holes 12a and 14a of the wide portion 12 projecting outward and the reinforcing rib 14 face the outside.

The core material 10 is arranged in the gap 25 between the pair of restraint plates 21, and a plurality of first length bolts 31 are inserted through the pair of restraint plates 21 and the spacer 16 and tightened by the nuts 33. The buckling restraint brace 100 is formed by inserting the second long bolt 41 through the side plate 22 and the restraint plate 21 and tightening them with the nut 43. As shown in the figure, the extension direction of the first long bolt 31 is the weak axis direction of the core material 10, and the extension direction of the second long bolt 41 is the strong axis direction of the core material 10.

According to the buckling restraint brace 100, a pair of restraint plates 21 and a pair of side plates 22 are tightly closed by a wooden restraint member 20 formed by tightening a plurality of first length bolts 31 and second length bolts 41 with nuts. Since the core material 10 is surrounded, the buckling restraint brace has high buckling strength. Further, since the steel core material 10 is surrounded by the wooden restraint material 20, even when the buckling restraint brace 100 is applied to the frame of a wooden building, it does not give an appearance disproportionate to the frame components. ..

In the buckling restraint brace 100 shown in the figure, the core material 10 is housed in the gap 25 of the wooden restraint member 20 with spacers 16 arranged on the left and right sides of the narrow width portion 13, and the narrow width portion 13 is accommodated. A protrusion 15 projecting laterally from the side surface is engaged with the engagement hole 22c.

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 side plate 22 of the wooden restraining material 20. Further, between the reinforcing rib 14 and the slit 24 of the restraining plate 21 of the wooden restraining material 20, a gap G2 having a width t2 in the longitudinal direction of the reinforcing rib 14 and a width t1 is provided on the side of the reinforcing rib 14. ing. In this way, when the structure surface to which the buckling restraint brace 10 is attached is greatly deformed by having a gap G1 between the side surface of the wide portion 12 and the side plate 22 of the wooden restraint member 20, this It is possible to absorb the deformation of the core material 10 in the gap G1 and eliminate the so-called additional bending moment acting on the wooden restraint material 20. On the other hand, since the gap G2 exists between the slit 24 and the reinforcing rib 14, when the core material 10 expands and contracts according to the deformation of the structure surface, the gap G2 absorbs the expansion and contraction of the core material 10. It is possible to solve the problem that the stretchable core material 10 comes into contact with the wall surface of the slit 24 and the wooden restraining material 20 is damaged.

Further, as shown in FIG. 6, since the boundary region A between the wide portion 12 and the narrow portion 13 is a changing region in which the flat area and the cross-sectional area of the core material 10 change, the additional bending moment acting on the core material 10 Is an additional bending absorption area that can absorb in this change area. In this way, the additional bending moment acting on the core material 10 is effectively absorbed in the boundary region A between the wide portion 12 and the narrow width portion 13 of the core material 10, and the side plate 22 of the core material 10 and the wooden restraining material 20 The gap G1 provided between them can prevent the additional bending moment acting on the core material 10 from acting on the side plate 22 of the wooden restraining material 20.

Further, by providing the narrow width portion 13 on the central side of the core material 10, a relatively large gap G3 existing between the narrow width portion 13 and the side plate 22 (the wide portion 12 and the side plate on the end side of the core material 10) A spacer 16 is interposed in the gap G3 to close the gap G3 with respect to the gap G1 between 22), thereby closing the gap G3 in the strong axial direction of the core material 10 (parallel to the wide surface 11a of the core material 10). Buckling in any direction) can be prevented. Therefore, the overall buckling of the buckling restraint brace 100 is suppressed, and the compressive strength of the buckling restraint brace 100 is improved, which is excellent for the frame in which the buckling restraint brace 100 is incorporated and the building including this frame. It can give a seismic reinforcement effect.

<Example of application of buckling restraint brace to frame>
Next, an example of applying the buckling restraint brace to the frame will be described with reference to FIGS. 7 and 8. Here, FIG. 7 is a diagram showing a state in which the buckling restraint brace according to the first embodiment is incorporated in a frame such as a wooden building. Further, FIG. 8 is a diagram for explaining the deformation mode of the frame at the time of a large earthquake and the additional bending moment at the buckling restraint brace joint due to the deformation of the frame. The buckling restraint brace in the illustrated example is incorporated into the frame of an S (S: Steel) building, the frame of an RC building, and the frame of an SRC (SRC: Steel Reinforced Concrete) building in addition to the frame of a wooden building. It may be.

The frame S shown in FIG. 7 is formed by wooden columns C and beams B constituting a wooden building or the like. Gusset plate GP made of flat steel is attached to the two corners at diagonal positions. Finstifuna FS is welded to the surface of the gusset plate GP so as to be orthogonal 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 O of the column core L1 of the column C and the beam core L2 of the beam B. Then, the buckling restraint brace 100 is also arranged in a linear shape passing through both intersections O at diagonal positions.

The gusset plate GP and the wide portion 12 of the core material 10 are joined by high tension bolts via the splice plate SP, and the feasibility study FS and the reinforcing rib 14 are joined by high tension bolts via the splice plate SP.

As shown in FIG. 8, in the buckling restraint brace joint due to the deformation of the structural surface during a large earthquake, when the joint is regarded as rigid, the additional bending moment shown in the following equation (1) Can work.

According to the buckling restraint brace 100, the buckling restraint brace 100 is attached by providing a gap G1 having a width t1 between the side surface of the wide portion 12 of the core material 10 and the side plate 22 of the wooden restraint material 20. When the structural surface is significantly deformed, the gap G1 can absorb the deformation of the core material 10 and eliminate the effect of the additional bending moment on the wooden restraining material 20. Further, between the reinforcing rib 14 and the slit 24 of the restraining plate 21 of the wooden restraining material 20, a gap G2 having a width t2 in the longitudinal direction of the reinforcing rib 14 and a width t1 is provided on the side of the reinforcing rib 14. As a result, when the core material 10 expands and contracts in response to the deformation of the structure surface, the expansion and contraction of the core material 10 can be absorbed by the gap G2, and the expandable and contracting core material 10 comes into contact with the wall surface of the slit 24. The problem that the wooden restraint 20 is damaged can be solved.

[Buckling restraint brace according to the second embodiment]
Next, an example of the core material forming the buckling restraint brace according to the second embodiment will be described with reference to FIGS. 9 to 11. Here, FIG. 9 is a perspective view showing an example of the core material forming the buckling restraint brace according to the second embodiment together with the spacer, and FIG. 10 is an example of the buckling restraint brace according to the second embodiment. It is a vertical sectional view. Further, FIG. 11 is an enlarged view of the XI portion of FIG. 10, showing that the force acting locally from the convex portion on the surface of the core material is diffused through the interpolation plate and transmitted to the restraint plate. It is a figure explaining.

The buckling restraint brace 100A is different from the buckling restraint brace 100 in that the interpolation plate 17 is interposed between the wide surface 11a of the core material 10 and the restraint plate 21. As the interpolation material 17, either a steel plate or a wooden plate may be applied, and as the wooden plate, for example, LVL (Laminated Veneer Lumber: single plate laminated material) can be applied. In this embodiment as well, the protrusions 15 may project from the upper and lower planes of the narrow portion 13.

On the wide surface of the interpolation material 17, a slit 18 is provided at an end portion in the longitudinal direction thereof at a position corresponding to the reinforcing rib 14 of the core material 10 so as not to interfere with the reinforcing rib 14. Further, the interpolation material 17 is provided with a bolt hole 17a at a position corresponding to the bolt hole 16a provided in the spacer 16, and the first long bolt 31 shown in FIG. 2 is inserted therethrough. There is.

According to the buckling restraint brace 100A, due to the higher-order buckling deformation of the core material 10, a compressive force P acts locally from the core material 10 to the restraint plate 21 as shown in FIG. 11, and this local compression force P acts. It is possible to prevent the restraint plate 21 from being damaged due to the force. The action of the local force P in this way can lead to damage to the wooden restraint plate 21. Therefore, by interpolating the interpolation plate 17 between the wide surface 11a of the core material 10 and the restraining plate 21, the force P acting from the convex portion 10a of the higher-order buckling deformation of the core material 10 is the interpolation plate 17. First, the transmitted force P spreads in the interpolation plate 17, and the force diffused in the interpolation plate 17 acts as a dispersion force q on the wooden restraint plate 21. As a result, damage to the wooden restraint plate 21 due to the plurality of local forces P acting on the core material 10 is effectively suppressed.

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

In the design of the buckling restraint brace, the following equation (2) is satisfied and the buckling restraint brace is designed so that the entire buckling does not occur.

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 material satisfies the following equation (4).

Equation (4) is shown in FIG. 12 as the entire buckling flexion line of the buckling restraint brace. In FIG. 12, the upper side of the entire seat bending line is the safety zone, and the lower side is the danger zone. , And the yield bending strength of the wooden restraint is set. The overall buckling bending line of the buckling restraint brace shown in FIG. 12 is applicable to both the overall buckling of the core material in the weak axial direction and the overall buckling in the strong axial direction.

In addition to examining the relationship between the yield bending strength of the wooden restraint and the bending moment acting, the allowable bending strength of the short-term wooden restraint may be larger than the bending moment acting during the yielding of the core material. It is better to check it together (formula omitted).

<Examination of sunk destruction of wooden restraint material>
Next, a method for examining the sinking fracture of the wooden restraint material will be described. 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.

In addition to checking the relationship between the proof stress of the restraint plate and the stiffening force acting on it, the allowable proof stress of the restraint plate for a short period of time is larger than the proof stress acting when the core material yields. It is good to check (formula omitted).

<Examination of specifications of the first long bolt (weak axial bolt) and the second long bolt (strong axial bolt)>
Next, a method of setting the specifications of the first long bolt (weak axial direction bolt) and the second long bolt (strong axial direction bolt) will be described.

When setting the specifications for the first long bolt (weak axial bolt) and the second long bolt (strong axial bolt), the total yield strength of each long bolt should be greater than or equal to the total stiffening force acting on the wooden restraint. The specifications of each long bolt (yield stress degree and number of first long bolt and second long bolt, effective cross-sectional area (effective per bolt) are set so as to satisfy the following formula (6). Determine the total effective cross-sectional area), etc. based on the cross-sectional area and the number of bolts.

It should be noted that the configuration or the like described in the above embodiment may be another embodiment in which other components are combined, and the present invention is not limited to the configuration shown here. This point can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form thereof.

10: Core material, 11a: Wide surface, 11b: Narrow surface, 12: Wide part, 12a: Bolt hole, 13: Narrow part, 14: Reinforcing rib, 14a: Bolt hole, 15: Protrusion, 16: Spacer, 16a : Bolt hole, 17: Insert plate, 17a: Bolt hole, 20: Wooden restraint, 21: Restraint plate, 21a: First bolt hole, 21b: First bolt hole unit, 21c: Second bolt hole, 22: Side plate, 22a: 2nd bolt hole, 22b: 2nd bolt hole unit, 22c: Engagement hole, 24: Slit, 25: Gap, 31: First long bolt, 32: Washer, 33: Nut, 34: Washer, 41: Second long bolt, 42: Washer, 43: Nut, 44: Washer, 100, 100A: Buckling restraint brace, G1, G2, G3: Gap, A: Additional bending absorption area (boundary area), S: Frame (Structure surface), C: Pillar, B: Beam, GP: Gusset plate, FS: Finstifuna, SP: Splice plate

Claims (5)

With a steel plate-shaped core material,
A pair of wooden restraint plates arranged so as to face the two wide surfaces of the core material, and the pair of restraint plates arranged so as to face the two narrow surfaces of the core material. With a pair of wooden side plates connected to, and a wooden restraint formed by,
A first bolt hole is formed at a corresponding position of the pair of restraint plates, a first bolt hole unit is formed by the corresponding first bolt hole, and a first long bolt is formed in each of the plurality of first bolt hole units. Is inserted and the nut is tightened,
A second bolt hole is formed at a position corresponding to the pair of side plates and the restraint plate, a second bolt hole unit is formed by the corresponding second bolt hole, and a second bolt hole unit is formed in each of the plurality of second bolt hole units. A buckling restraint brace characterized by a double bolt inserted and nut-tightened. The buckling restraint brace according to claim 1, wherein the contact surface between the restraint plate and the side plate is joined by an adhesive and tightened by the second long bolt. Reinforcing ribs orthogonal to the wide surface are joined to the wide surface at the end portion in the longitudinal direction of the core material to form a cross section.
The buckling restraint brace according to claim 1 or 2, wherein a slit that does not interfere with the reinforcing rib is provided at a position corresponding to the reinforcing rib in the wooden restraint material. The buckling restraint brace according to claim 3, wherein a gap is provided between the slit and the reinforcing rib in a plan view. The buckling restraint brace according to any one of claims 1 to 4, wherein an interpolation plate is interposed between the wide surface of the core material and the restraint plate.

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