JP7175694B2 - buckling restraint brace - Google Patents

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.

Therefore, there have been proposed buckling restraint braces that are suitable for use by being incorporated in the framework of wooden buildings such as wooden houses. 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 a laminated material to the restraining material, and the laminated material is formed by laminating lamina parallel to the core material (see, for example, Patent Document 1).

Japanese Patent No. 4901491

For a buckling restraint brace in which a steel core is surrounded by a wooden restraint, for example, when the frame is greatly deformed during a major earthquake, the so-called additional bending moment (or simply , additional bending) can act on the restraint. This additional bending moment acting on the wooden restraint can lead to the restraint failing. When the restraining material is damaged, the buckling restraint function of the core material by the restraining material is deteriorated, and the core material may buckle. Patent Literature 1 does not mention measures to prevent such a so-called additional bending moment from acting on the restraint member.

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 damage caused by acting on the brace.

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
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,
A slit that does not interfere with the reinforcing rib is provided in the wooden restraint member at a position corresponding to the reinforcing rib,
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
A gap is provided between the side surface of the wide portion of the core material and the side plate.

According to this aspect, the core material has a narrow portion with a relatively narrow wide surface at the central side in the longitudinal direction, and a wide width with a relatively wide wide surface at the end portions in the longitudinal direction. By having a gap between the side of the wide part and the side plate that constitutes the wooden restraint material, even if the structural surface is greatly deformed, this gap will absorb the deformation of the core material. , the so-called additional bending moment acting on the wooden restraint can be eliminated. For example, the amount of deformation of the structural surface during a major earthquake is left to the discretion of the designer, such as the amount of deformation of the structural surface when the inter-story deformation angle is 1/100, the deformation amount of the structural surface when the inter-story deformation angle is 1/75, etc. , the amount of deformation of the end of the core material of the buckling restraint brace is calculated. Then, for example, by setting a gap larger than the calculated amount of deformation, it is possible to eliminate the additional bending moment from acting on the wooden restraint member. In addition, since the core material has a narrow width portion on the longitudinal center side and a wide width portion on the longitudinal end side, the narrow width portion on the central side can be a region that is easily plasticized. Furthermore, the plasticized region can be limited to the central narrow portion. Furthermore, since the boundary area between the wide width portion and the narrow width portion is a change area where the plane area and cross-sectional area of the core material change, the additional bending moment acting on the core material can be absorbed by this change area. Thus, in this aspect, the additional bending moment acting on the core material is effectively absorbed in the boundary region between the wide width portion and the narrow width portion of the core material, and is provided between the core material and the side plates of the wooden restraint plate. The gap prevents additional bending moments acting on the core from acting on the side plates of the wooden restraining plate.

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. If the buckling restraint brace is attached to the gusset plate so that the wide face of the core is parallel to the structural surface of the building, the core shall have reinforcing ribs perpendicular to the wide face parallel to the structural surface. Therefore, it is possible to increase the rigidity of the end portion of the core material in the outward direction of the structural surface. 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, a slit is provided at a position corresponding to the reinforcing rib of the wooden restraining member, and the slit prevents the wooden restraining member from interfering with the reinforcing rib.

Further, 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. It 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 wooden restraining member and the side plate may be made of solid wood, or may be made of laminated wood 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 processed by processing laminated lumber to produce two restraining members with an L-shaped cross section, turning them upside down, and connecting them while sandwiching the core material. requires. 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. A buckling restraint brace can be fabricated by Therefore, the buckling restraint brace is made easier to manufacture.

Another aspect of the buckling restraint brace according to the present invention is characterized in that a spacer is interposed between the side surface of the narrow portion of the core member and the wall surface of the side plate.

According to this aspect, by providing the narrow width portion on the central side of the core material, a relatively large gap exists between the narrow width portion and the side plate (more than the gap between the wide width portion on the end side of the core material and the side plate). A large gap) can be prevented from buckling in the direction of the strong axis of the core material (the direction parallel to the wide surface of the core material) by interposing a spacer in the gap to close the gap. As already mentioned, the narrow part on the central side of the core material is a plasticized region, but buckling of the core material (buckling in the direction of the strong axis) can be prevented by interposing spacers between the core material and the side plates. While suppressing the vibration, the vibration energy in the event of an earthquake or the like can be effectively absorbed by the plasticization of the narrow width portion of the core material. In addition, either a steel member or a wooden member may be applied to the spacer.

Another aspect of the buckling restraint brace according to the present invention is characterized by having a gap between the slit and the reinforcing rib in plan view.

According to this aspect, since the gap exists between the slit and the reinforcing rib, when the core material expands and contracts according to the deformation of the structural surface, the gap can absorb the expansion and contraction of the core material, It is possible to solve the problem that the elastic core material contacts 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 greater than or equal to the expansion/contraction amount of the core material. In addition, 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. 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 another aspect of the buckling restraint brace according to the present invention, projections protrude from the peripheral surface of the core member, and the projections are engaged with engagement holes formed in the wooden restraint member. characterized by

According to this aspect, the protrusion protruding from the peripheral surface of the narrow portion of the core member is engaged with the engaging hole formed in the wooden restraining member, so that it is inserted into the wooden restraining member. It is possible to prevent the core from biasing toward one end of the wooden restraint. Therefore, when the core material is biased toward one end of the wooden restraint, the problem that the other end of the wooden restraint without the core material becomes a weak portion in terms of strength can be solved. can. Here, when the peripheral surface of the narrow portion of the core material has left and right side surfaces and upper and lower planes perpendicular to the left and right side surfaces, the protrusions project from the left and right side surfaces respectively. Any form of overhanging form can be applied.

Another aspect of the buckling restraint brace according to the present invention is characterized in that 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 compressive 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 do. By interposing the insert plate between the wide surface of the core material and the restraining plate, the force acting from the convex portion of the higher-order buckling deformation of the core material is first transmitted to the insert plate, and the transmitted force is transferred to the insert plate. The force spread within the plate and spread within the insert plate will act on the wooden restraining plate. This effectively suppresses damage to the wooden restraint plate due to multiple localized forces acting from the core material.

Further, another aspect of the buckling restraint brace according to the present invention is characterized in that the side plate is fixed to the restraint plate with a fixture or an adhesive.

According to this aspect, since the side plate is fixed to the restraint plate with a fixing metal fitting or an adhesive, the production of the wooden restraint member is further facilitated. Here, screws, nails, and the like can be used as fixing metal fittings.

Another aspect of the buckling restraint brace according to the present invention is characterized in that the specifications of the wooden restraining member and the core member are set so as to satisfy the following formula (A).

According to this aspect, each specification of the wooden restraining material and the core material can be appropriately set based on the relationship between the penetration strength and the stiffening force peculiar to the wooden restraining material. Here, "specifications" refer to the width and thickness of the core material, the yield strength of the core material, the design axial force of the wooden restraint material (the cross-sectional dimensions and cross-sectional rigidity of the wooden restraint material that can withstand it, Young's modulus (material) etc.).

In another aspect of the buckling restraint brace according to the present invention, the side plate is fixed to the restraining plate by a plurality of fixing metal fittings, and the pitch of the fixing metal fittings is set so as to satisfy the following formula (B). characterized by being

According to this aspect, the pitch of the fixtures (or the number of fixtures) can be appropriately set so as to have a shear strength greater than or equal to the shear force acting on the connecting portion between the restraint plate and the side plate.

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 frame structure of a wooden building, etc. It is possible to eliminate the bending moment acting on wooden restraints and causing them to break.

FIG. 2 is a perspective view showing an example of a core material forming the buckling restraint brace according to the first embodiment together with a spacer; 1 is a perspective view of an example of a wooden restraint forming a buckling restraint brace according to the first embodiment; FIG. 1 is a perspective view of an example of a buckling restraint brace according to a first embodiment; FIG. FIG. 4 is a view in the direction of arrow IV in FIG. 3; 4 is a view in the direction of arrow V in FIG. 3. FIG. 4 is a view taken along line VI-VI of FIG. 3; FIG. 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 is a perspective view showing an example of a core material forming a buckling restraint brace according to a second embodiment together with a spacer; FIG. 10 is a vertical cross-sectional view of an example of a buckling restraint brace according to a second embodiment; FIG. 11 is an enlarged view of the XI section in FIG. 10 and is a view for explaining that the force acting locally from the projections on the surface of the core material is diffused via the inserting plate and transmitted to the restraining plate. FIG. 11 shows a general 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]
<Core material>
First, with reference to FIG. 1, an example of the core material forming the buckling restraint brace according to the first embodiment will be described. Here, FIG. 1 is a perspective view showing an example of a core material forming the buckling restraint brace according to the first embodiment together with a spacer.

The core material 10 is formed of an elongated flat steel, has a narrow portion 13 with a relatively narrow width of the wide surface 11a at the central side in the longitudinal direction, and has a wide width at the end portions in the longitudinal direction. It has a wide portion 12 in which the width of the surface 11a is relatively wide. 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 at the center in the longitudinal direction and the wide width portions 12 at the ends thereof in the longitudinal direction, the narrow width portion 13 at the center side can be easily plasticized. Furthermore, the plasticized region can be limited to the central narrow portion 13 .

As will be described below, 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. 7) attached to the gusset plate via a splice plate. Bolt holes 12a and 14a are provided for bolting. When the buckling restraint brace 10 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.

At the central position of the narrow portion 13 of the core member 10 , cylindrical projections 15 made of steel protrude from the left and right side surfaces of the narrow portion 13 (an example of the peripheral surface of the narrow portion 13 ). The protrusion 15 is joined to the side surface of the narrow portion 13 by stud welding or the like. This projection 15 engages with an engaging hole formed in a wooden restraining member (see FIG. 2) described below. In addition, the projection 15 may project from the upper and lower planes of the narrow portion 13. In this case, the wooden restraining member (see FIG. 2) has an engaging hole at a position corresponding to the restraining plate 21. and the projection 15 engages here.

Elongated square prism-shaped spacers 16 are arranged in the X1 direction on the left and right sides of the narrow portion 13, and the core material 10 is assembled with the spacers 16 arranged on the left and right sides of the narrow portion 13. are housed inside the wooden restraint shown below. Spacer 16 may be either a steel member or a wooden member. Also, the spacer 16 may have a shape other than the illustrated example, such as a cylindrical shape.

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

The wooden restraining member 20 has a pair of restraining plates 21 and a pair of side plates 22 connecting the pair of restraining plates 21, and the core member 10 is disposed in a gap 25 between the pair of restraining plates 21. It's becoming A pair of wooden constraining plates 21 are disposed so as to face the two wide surfaces 11a (see FIG. 1) of the core member 10, and a pair of wooden side plates 21 connected to the pair of constraining plates 21 are arranged. 22 are arranged so as to face the two narrow surfaces 11b (see FIG. 1) of the core member 10. As shown in FIG. The side plate 22 is fixed to the restraint plate 21 with fixing metal fittings 23 such as screws and nails at a predetermined pitch t3. A method for setting the pitch t3 will be described in detail below. By fixing the pair of side plates 22 to the pair of restraining plates 21 with the fixing metal fittings 23 in this manner, the wooden restraining member 20 having a closed structure with four face members can be easily manufactured.

The left and right side plates 22 are formed with engagement holes 22a at the central positions in the longitudinal direction thereof, with which the projections 15 of the core member 10 are engaged. The protrusions 15 of the core material 10 are engaged with the engagement holes 22a formed in the wooden restraining material 20, so that the core material 10 inserted into the wooden restraining material 20 is pulled out of the wooden restraining material 20. It is possible to prevent bias toward one end. Therefore, when the core member 10 is biased toward one end of the wooden restraint member 20, the other end of the wooden restraint member 20, where the core member 10 is not present, becomes a weak portion in terms of strength. does not occur.

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 red pine, larch, fir, spruce, and the like. The wooden restraining member 20 shown in the figure has the side plate 22 fixed to the restraining plate 21 with fixing metal fittings 23 such as screws. .

Slits 24 that do not interfere with the reinforcing ribs 14 are provided at positions corresponding to the reinforcing ribs 14 when the core material 10 is accommodated in the gaps 25 in the end portions of the restraining plate 21 .

<Buckling restraint brace>
Next, an example of the buckling restraint brace according to the first embodiment, which is formed of the core material 10 and the wooden restraint material 20 described above, will be described with reference to FIGS. 3 to 6. FIG. Here, FIG. 3 is a perspective view of an example of the buckling restraint brace according to the first embodiment, and FIGS. and a view taken along the line VI-VI.

In the buckling restraint brace 100, a wooden restraint member 20 is disposed so as to partially surround the narrow portion 13 and the wide portion 12 of the core member 10, and the cross-shaped portion at the end of the wide portion 12 is restrained by wood. The entire member 20 is constructed so as to protrude from the end portion of the material 20, and bolt holes 12a and 14a of the wide portion 12 protruding outward and the reinforcing rib 14 are exposed to the outside. According to the buckling restraint brace 100, since the steel core 10 is surrounded by the wooden restraint 20, even when the buckling restraint brace 100 is applied to the frame of a wooden building, it can be used as a structural member. Does not give an unprofessional appearance.

In the gap 25 of the wooden restraint member 20, the core member 10 is accommodated with the spacers 16 arranged on the left and right sides of the narrow portion 13, and the protrusions 15 protruding laterally from the side surfaces of the narrow portion 13. is engaged with the engaging hole 22a.

In the buckling restraint brace 100, a gap G1 having a width t1 is provided between the side surface of the wide portion 12 of the core member 10 and the side plate 22 of the wooden restraint member 20. As shown in FIG. Further, between the reinforcing rib 14 and the slit 24 of the restraining plate 21 of the wooden restraining member 20, there is provided a gap G2 having a width t2 in the longitudinal direction of the reinforcing rib 14 and a width t1 on the lateral side of the reinforcing rib 14. ing. Since the gap G1 is provided between the side surface of the wide portion 12 and the side plate 22 of the wooden restraint member 20 in this way, when the structural surface to which the buckling restraint brace 10 is attached is greatly deformed, this Deformation of the core material 10 can be absorbed by the gap G1, and so-called additional bending moment acting on the wooden restraint material 20 can be eliminated. 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 structural surface, the expansion and contraction of the core material 10 can be absorbed by the gap G2. It is possible to solve the problem that the elastic core material 10 contacts the wall surface of the slit 14 and the wooden restraint material 20 is damaged.

Further, as shown in FIG. 6, the boundary region A between the wide portion 12 and the narrow portion 13 is a changing region where the plane area and cross-sectional area of the core material 10 change. is an additional bending absorption area that can absorb in this transition area. In this way, the additional bending moment acting on the core member 10 is effectively absorbed by the boundary region A between the wide portion 12 and the narrow portion 13 of the core member 10, and the side plates 22 of the core member 10 and the wooden restraint plate 20 are effectively absorbed. The gap G1 provided therebetween makes it possible to prevent the additional bending moment acting on the core member 10 from acting on the side plates 22 of the wooden restraining plate 20 .

Furthermore, by providing the narrow width portion 13 on the central side of the core material 10, a relatively large gap G3 exists between the narrow width portion 13 and the side plate 22 (the wide width portion 12 on the end side of the core material 10 and the side plate 22). A gap larger than the gap G1 between the core members 10) is closed by interposing a spacer 16 in the gap G3 to close the gap G3 in the strong axial direction of the core member 10 (parallel to the wide surface 11a of the core member 10). direction) buckling 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. Excellent seismic reinforcement effect can be imparted.

<Example of applying buckling restraint brace to frame>
Next, with reference to FIGS. 7 and 8, an application example of the buckling restraint brace to the frame will be described. 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 structure such as a wooden building. FIG. 8 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 (S: Steel) buildings, the framework of RC buildings, and the framework of SRC (SRC: Steel Reinforced Concrete) buildings in addition to the framework of wooden buildings. may be

A frame S shown in FIG. 7 is formed of 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. 8, 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 buckling restraint brace 10 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 on which the wooden restraint member 20 rests is greatly deformed, the deformation of the core member 10 can be absorbed by the gap G1, and the application of the additional bending moment to the wooden restraint member 20 can be eliminated. Between the reinforcing rib 14 and the slit 24 of the restraining plate 21 of the wooden restraining member 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. Therefore, when the core material 10 expands and contracts according to the deformation of the structural surface, the expansion and contraction of the core material 10 can be absorbed by the gap G2, and the expanding and contracting core material 10 contacts the wall surface of the slit 14. The problem that the wooden restraint member 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. FIG. Here, FIG. 9 is a perspective view showing an example of a core material forming the buckling restraint brace according to the second embodiment together with a spacer, and FIG. It is a longitudinal cross-sectional view. Also, FIG. 11 is an enlarged view of the XI section of FIG. 10, showing that the force acting locally from the projections on the surface of the core material is diffused through the insertion plate and transmitted to the restraining plate. It is a figure explaining.

The buckling restraint brace 100A differs from the buckling restraint brace 100 in that an inserting plate 17 is interposed between the wide surface 11a of the core member 10 and the restraining plate 21. As shown in FIG. Either a steel plate or a wooden plate may be applied as the insert member 17, and LVL (Laminated Veneer Lumber), for example, may be applied as the wooden plate. Also in the present embodiment, the projection 15 may project from the upper and lower planes of the narrow portion 13 .

A slit 18 is formed at a longitudinal end of the wide surface of the insert member 17 at a position corresponding to the reinforcing rib 14 of the core member 10 so as not to interfere with the reinforcing rib 14 .

According to the buckling restraint brace 100A, high-order buckling deformation of the core material 10 locally acts on the restraint plate 21 from the core material 10 as shown in FIG. Damage to the restraining plate 21 due to force can be suppressed. Such localized force P can lead to breakage of the wooden restraining plate 21 . Therefore, by interposing an inserting plate 17 between the wide surface 11a of the core member 10 and the restraining plate 21, the force P acting from the convex portion 10a of the higher-order buckling deformation of the core member 10 is reduced by the inserting plate 17 , the transmitted force P spreads in the insertion plate 17, and the force diffused in the insertion plate 17 acts on the wooden constraining plate 21 as a distributed force q. As a result, damage to the wooden restraining plate 21 due to multiple local forces P acting from the core material 10 is effectively suppressed.

[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. 12 as the overall buckling line of the buckling restraint brace. In FIG. 12, 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 strength of the wooden restraint is set.

In addition to examining the relationship between the yield bending strength of the wooden restraining material and the bending moment acting on it, the short-term allowable bending strength of the wooden restraining material becomes larger than the bending moment acting when the core material yields. It is better to check this together (the formula is 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.

In addition to checking the relationship between the above-described immersion resistance of the restraint plate and the stiffening force acting, it is also necessary to check that the short-term allowable immersion resistance of the restraint plate is greater than the stiffening force that acts when the core material yields. It is better to check (the formula is omitted).

<Examination of the pitch of the fixing bracket that connects the side plate to the restraint plate>
Next, a method of setting the pitch of the fixtures that connect the side plates to the restraint plates will be described. First, in order to prevent shear failure at the joint between the restraining plate and the side plate, it is verified that the following formula (6) is satisfied.

In order to satisfy the above formula (6), the pitch of the fixtures can be set by the following formula (7).

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: core material, 11a: wide surface, 11b: narrow surface, 12: wide portion, 12a: bolt hole, 13: narrow portion, 14: reinforcing rib, 14a: bolt hole, 15: projection, 16: spacer, 17 : Insertion plate 20: Wooden restraint member 21: Restraint plate 22: Side plate 22a: Engagement hole 23: Fixing bracket (screw) 24: Slit 25: Gap 100, 100A: Buckling restraint brace , G1, G2: Gap, A: Additional bending absorption area (boundary area), S: Frame (structure surface), C: Column, B: Beam, GP: Gusset plate, FS: Fin stiffener, SP: Splice plate

Claims (9)

A plate-like core material made of steel,
A pair of constraining plates , which are wooden face members arranged to face the two wide faces of the core material, and arranged to face the two narrow faces of the core member, a wooden restraint member having a closed structure with four face members formed by a pair of side plates that are wooden face members connected to a pair of restraint plates;
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,
A slit that does not interfere with the reinforcing rib is provided in the wooden restraint member at a position corresponding to the reinforcing rib,
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
A buckling restraint brace, wherein a first gap is provided between a side surface of the wide portion of the core member and the side plate. The first gap is a gap for preventing an additional bending moment for preventing an additional bending moment from acting on the side plate when the core material deforms and contacts the side plate. A buckling restrained brace according to claim 1. 3. A buckling restraint brace according to claim 1, wherein a spacer is interposed between the side surface of said narrow portion of said core member and the wall surface of said side plate. A buckling restrained brace according to any one of claims 1 to 3 , characterized in that it has a second gap between said slit and said reinforcing rib in plan view. 4. A protrusion protrudes from the peripheral surface of said narrow portion of said core material, and said protrusion is engaged with an engaging hole formed in said wooden restraint member. A buckling restrained brace according to any one of Claims 1 to 3. A buckling restrained brace according to any one of claims 1 to 5 , characterized in that an insert plate is interposed between the wide surface of the core member and the restraint plate. 2. A buckling restrained brace according to claim 1, wherein said side plate is fixed to said restraint plate with a fixture or an adhesive. The buckling restraint brace according to any one of claims 1 to 7 , characterized in that the specifications of the wooden restraining member and the core member are set so as to satisfy the following formula (A).

The side plate is fixed to the restraint plate by a plurality of fixing metal fittings, and the pitch of the fixing metal fittings is set so as to satisfy the following formula (B). 9. A buckling restrained brace as claimed in claim 8 when dependent on 6.

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