JP2023049140A - buckling restraint brace - Google Patents

Abstract

To provide a buckling restraint brace with strong ends capable of causing a smooth buckle of higher-order modes in its weak axis direction in the whole area of a core member.SOLUTION: A buckling restraint brace 100 includes: a plate-like core member 10 made of steel; a pair of restraint members 30 made of square steel pipe, which are arranged so as to face two wide sides 10a of the core member 10; and an unbonded member 20 interposed between the core member 10 and the restraint member 30. The end reinforcing members 60 are inserted inside the restraint member 30 at both ends and bonded to the inner surface of the restraint member 30.SELECTED DRAWING: Figure 1

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 frames (column/beam frames, roof frames, 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.

Here, Patent Document 1 relates to a buckling restraint brace in which a core material is restrained by a restraining material formed of a pair of square steel pipes. Flexion restraint braces have been suggested. Specifically, a core material having joints for joining with other members at both ends of a plate-like portion, and a restraining material arranged to face each surface perpendicular to the weak axis direction of the plate-like portion. A buckling restraint brace comprising:

In this buckling restraint brace, an inserting plate is provided between the plate-like portion and the restraining material to contact the restraining material, and the restraining material made of a rectangular steel pipe has a corner portion having a curved surface area at the intersection of each surface portion. It has A welded portion for fixing the restraining member and the inserting plate is provided between the surface of the inserting plate that contacts the restraining member and the corner portion of the restraining member.

Japanese Patent No. 6445862

According to the buckling restraint brace described in Patent Document 1, it is easy to use a member such as a ready-made square steel pipe as a restraint material, and the restraint is restrained by receiving a pressing force from the core material without incurring an increase in cost. It becomes possible to suppress local destruction of the material.

By the way, the buckling restraint brace is incorporated into the building frame by bolting both ends thereof to connection jigs such as brackets and gusset plates provided at the corners of the building frame. become. When the building frame is deformed during an earthquake, external forces such as horizontal force during an earthquake enter the ends of the buckling restraint braces via brackets, etc., and the external force is applied to the entire area from the ends of the core material as a compressive force. By transmitting as such, the entire area of the core material is plastically deformed, so that the energy absorption performance at the time of an earthquake is exhibited. More specifically, when compressive force acts on the core material, high-order mode buckling (wave-like deformation) occurs in the weak axis direction over the entire area, so that the entire core material is made uniform as much as possible. By buckling, the overall plastic deformation performance of the buckling restraint brace can be exhibited.

On the other hand, the strength of the ends of the buckling restraint brace, to which the external force is directly input during an earthquake, is weak. Due to the inability of the core to undergo higher order mode buckling across it, it will develop much less yield strength than the initial yield strength of the buckling restrained brace. Reinforcing the ends of the buckling-restrained brace is therefore extremely important from the standpoint of ensuring that the buckling-restrained brace exhibits its initial energy absorption performance. Note that Patent Document 1 does not specifically mention reinforcement of the ends of the buckling restraint brace.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems. is intended to provide

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 restraining members made of rectangular steel pipes arranged to face the two wide surfaces of the core member;
Having an unbonded material interposed between the core material and the restraining material,
End reinforcing members are inserted through the interior of both ends of the restraining member and joined to the inner surface of the restraining member.

According to this aspect, in the buckling restraint brace in which the steel plate-shaped core material and the two wide faces thereof are restrained by a pair of restraint members made of rectangular steel pipes, end reinforcements are provided inside both ends of the restraint members. Since the material is inserted and joined to the inner surface of the restraining material, the end strength of the buckling restraint brace can be increased. By effectively reinforcing the end portions of the pair of restraint members, the end portions of the core material sandwiched by the pair of restraint members are reinforced, and the core material is reinforced not only at the end portions but also over the entire area. , buckling (wavy deformation) of the higher-order mode can be smoothly generated in the direction of the weak axis.

Here, the "end reinforcing material" includes pieces of shaped steel such as angle steel, channel steel, and H-shaped steel, as well as rectangular steel pipes with smaller cross-sectional dimensions than the rectangular steel pipes that form the restraining material. .

Moreover, the unbonded material is formed of an elastic material having deformability such as butyl rubber. By interposing this unbonded material between the wide surface of the core material and the restraining material, the thickness of the unbonded material is used as a clearance, and when the core material receives a compressive force, high-order mode buckling occurs within this clearance. It becomes possible to let

In the core material, a slit may be provided on the wide surface of the core material in order to effectively cause higher-order mode buckling in the direction of its weak axis. Since the formation of the slits on the wide surface weakens the strength of the core material in the direction of the strong axis, spacers may be inserted into the slits on the wide surface as necessary.

Also, another aspect of the buckling restraint brace according to the present invention comprises:
The end reinforcement is channel steel.

According to this aspect, by applying the channel steel as the end reinforcing material, regardless of the position of the seam of the square steel pipe, the channel steel can be easily inserted from the end of the square steel pipe into the inside thereof and joined. becomes possible.

In another aspect of the buckling restraint brace according to the invention,
The length of the end reinforcing member is set to a length of 2 to 3 wavelengths in wavy deformation, which is buckling of a higher-order mode occurring in the weak axis direction of the core member. .

According to this aspect, the length of the end reinforcing material is set to the length of 2 to 3 wavelengths in the wavy deformation, which is the buckling of the higher-order mode occurring in the weak axis direction of the core material. , while the ends of the buckling restraint brace are sufficiently reinforced, the center side of the core material can be smoothly wavy-shaped deformed.

In another aspect of the buckling restraint brace according to the invention,
A pair of joining plates are fixed to both ends of the core material and are joined to other members perpendicular to the wide surface,
A reinforcing plate is fixed to the pair of joint plates, and an end portion of the restraint member is accommodated in a space formed by the wide surface, the pair of joint plates, and the reinforcing plate.

According to this aspect, a pair of joint plates perpendicular to the wide surface are fixed at both ends of the core material, and a reinforcing plate is fixed to the pair of joint plates. Since the ends of the restraining material are housed in a space where the restraining material is reinforced by the end reinforcing material, a buckling structure with a high-strength end structure is achieved. It becomes a restraining brace. Here, the other member to which the joint plate is joined is, for example, a connection jig such as a bracket or gusset plate projecting from the corner of the building frame into the structure plane. Further, when the ends of the core material are webs, the pair of joint plates perpendicular to the webs will be a pair of flanges.

Also, another aspect of the buckling restraint brace according to the present invention comprises:
A pair of stiffeners connect both sides of the pair of restraint members on the sides of the core member,
The core member is surrounded by the pair of restraining members and the pair of stiffening members.

According to this aspect, the pair of stiffeners connect both sides of the pair of restraint members on the sides of the core member, so that the deformation of the core member in the width direction (strong axis direction) is constrained by the stiffeners. be able to.

Further, the buckling restraint brace according to the present invention may have a form in which an insert plate is interposed between the unbonded material and the restraint material. According to this embodiment, an inserting plate made of steel, for example, is interposed between the unbonded material and the restraining material, so that the pressing force due to the buckling of the core material in the weak axis direction of the high-order mode is applied to the restraining material. By acting directly, it is possible to effectively suppress the local destruction of the restraining material.

As can be understood from the above description, according to the buckling-restrained brace of the present invention, it is possible to provide a buckling-restrained brace that has high strength at the ends and guarantees buckling of higher-order modes throughout the core material. can be done.

1 is an exploded perspective view of an example of a buckling restraint brace according to an embodiment; FIG. FIG. 4 is a vertical cross-sectional view of the buckling restrained brace in a pre-assembled state with respect to the end portion of the buckling restrained brace according to the embodiment; 1 is a perspective view of an example of a buckling restraint brace according to embodiments; FIG. FIG. 4 is a cross-axis vertical cross-sectional view of an assembled buckling-restrained brace with respect to an end of the buckling-restrained brace according to an embodiment; FIG. 4 is a schematic vertical cross-sectional view of the buckling restraint brace in the direction orthogonal to the axis, illustrating a state in which a pressing force is applied from the core material to the restraint material during buckling in a higher-order mode. FIG. 4 is an axial vertical cross-sectional view of the buckling restraint brace, illustrating a state in which a pressing force is applied from the core material to the restraint material during buckling in a higher-order mode.

A buckling restraint brace according to embodiments 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 embodiment]
An example of a buckling restraint brace according to an embodiment will be described with reference to FIGS. 1 to 5. FIG. Here, FIG. 1 is an exploded perspective view of an example of the buckling restraint brace according to the embodiment, and FIG. It is a longitudinal cross-sectional view in the direction perpendicular to the axis. 3 is a perspective view of an example of the buckling restraint brace according to the embodiment, and FIG. 4 is a cross-axis view of the buckling restraint brace in the assembled state with respect to the end portion of the buckling restraint brace according to the embodiment. It is a vertical cross-sectional view of.

The buckling restraint brace 100 includes a core member 10, a pair of restraint members 30 disposed so as to face two wide surfaces 10a of the core member 10, and interposed between the core member 10 and the restraint members 30. and an unbonded material 20 to be used. In addition to the illustrated example, an insert plate may be interposed between the unbonded material 20 and the restraining material 30 .

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). By applying, the seismic energy absorbability due to the yield of the core material 10 is improved.

The core material 10 is formed of an elongated steel plate, has a narrow portion 11 in which the width of the wide surface 10a is relatively narrow at the central side in the longitudinal direction, and the width of the wide surface 10a at the end portions in the longitudinal direction. has a relatively wide wide portion 12 .

Since the core material 10 has the narrow width portion 11 at the center in the longitudinal direction and the wide width portions 12 at the end portions in the longitudinal direction, the narrow width portion 11 at the center side can be easily plasticized. Furthermore, the plasticized region can be limited to the central narrow portion 11 .

At the central position of the narrow portion 11 of the core material 10, two wide surfaces 10a of the narrow portion 11 are provided with cylindrical projections 15 made of steel. The protrusion 15 is joined to the wide surface 10a of the narrow portion 11 by welding or the like.

Elongated slits 14 are provided on both sides of the protrusion 15 of the narrow portion 11 of the core material 10, and steel spacers 17 are inserted into the slits 14 in the X1 direction. .

The slits 14 are pores for adjusting the strength of the core material 10, and the spacers 17 prevent internal deformation of the core material 10 due to the provision of the slits 14 (deformation in the direction of the strong axis). Acts as a preventative. The spacer 17 inserted through the slit 14 is positionally regulated by a pair of restraining members 30 .

A joint plate 13 made of a pair of steel plates is joined by welding or the like to the wide portion 12 at both ends of the core material, perpendicular to the wide surface 10a thereof, and joined to another member.

The wide portion 12 and the joint plate 13 are provided with bolt holes 12a and 13a, respectively, and connection jigs (other members) such as brackets and gusset plates protruding into the structure plane from the corners of the building frame (not shown). ) are aligned with and bolted to.

A reinforcing plate 18 made of a steel plate is joined to the pair of joining plates 13 by welding or the like. The ends are adapted to be accommodated.

The unbonded material 20 is interposed between the narrow width portion 11 of the core material 10 and the restraint material 30, and with the thickness of the unbonded material 20 as a clearance, a compressive force acts on the core material 10 when the building frame is deformed. Higher-order mode buckling (wavy deformation) in the out-of-plane direction (weak axis direction) occurs in the narrow portion 11 .

As the unbonded material 20, an elastic material such as butyl rubber is applied. A projection hole 20a into which the projection 15 of the core material 10 is fitted is provided at the central position of the unbonded material 20 in the longitudinal direction.

The restraint member 30 is formed of a rectangular steel pipe having a rectangular cross section, and the side surface corresponding to the long side of the rectangle is in contact with the unbonded member 20 . A protrusion hole 30 a into which the protrusion 15 of the core member 10 is fitted is also provided on the side surface of the restraining member 30 that contacts the unbonded member 20 .

On the sides of the core member 10, stiffening members 50 made of a pair of steel plates connect both sides (side surfaces corresponding to the short sides of the rectangle) of the pair of restraint members 30 by welding or the like. It is surrounded by a restraining member 30 and a pair of stiffening members 50 .

As shown in FIG. 1 , end reinforcing members 60 are inserted through both ends of the restraint member 30 in the X2 direction and welded to the inner surface of the restraint member 30 . As a result, as shown in FIGS. 2 to 4, both ends of the pair of restraint members 30 are reinforced, and the reinforcement of both ends of the pair of restraint members 30 allows both ends of the buckling restraint brace 100 including the core member 10 to be reinforced. is reinforced.

Here, the end reinforcing member 60 is formed of a piece of shaped steel material such as angle steel, channel steel, H-shaped steel, or a piece of rectangular steel pipe having a smaller cross-sectional dimension than the rectangular steel pipe forming the restraining member 30. However, it is preferable to use channel steel as shown in the figure, from the viewpoint that it can be easily inserted from the end of the square steel pipe 30 into the inside thereof and welded, regardless of the position of the seam of the square steel pipe 30 .

In addition, the length t (see FIG. 1) of the end reinforcing member 60 is set to a length of 2 to 3 wavelengths in wavy deformation, which is buckling of a higher-order mode occurring in the weak axis direction of the core member 10. It is By setting the length of the end reinforcing member 60 to the above length, while the end of the buckling restraint brace 100 is sufficiently reinforced, the wavy deformation toward the central side of the core member 10 is smooth. possible to generate.

By reinforcing both ends of the restraining member 30 with the end reinforcing members 60 in this manner, the entire region of the core member 10 can be highly heightened with the minimum necessary reinforcement without increasing the plate thickness of the entire restraining member 30 . Since it is possible to cause buckling in the next mode, it also leads to a reduction in the manufacturing cost of the buckling restraint brace 100 .

Next, high-order mode buckling occurring in the weak axis direction of the core member 10 will be described with reference to FIG.

The buckling restraint brace 100 is incorporated into the building frame by bolting or the like to connection jigs provided at the corners or the like of the building frame at both ends thereof. When the building frame is deformed during an earthquake, an external force such as a horizontal force during an earthquake enters the end of the buckling restraint brace 100 via the connecting jig, and the external force spreads from the end of the core member 10 to the entire area. is transmitted as a compressive force N, the entire area of the core material 10 is plastically deformed, and the energy absorption performance at the time of an earthquake is exhibited. In other words, when the compressive force N acts on the core material 10, buckling (wave-like deformation) of a higher-order mode occurs in the direction of the weak axis in the entire area of the core material 10, so that the entire core material 10 is deformed as much as possible. The uniform buckling of the buckling restraint brace 100 allows the entire plastic deformation performance of the buckling restraint brace 100 to be exhibited.

As shown in FIG. 5B, the compression force N acting on the core material 10 causes buckling in a high-order mode, and the crests of the wavy deformation caused by the buckling come into contact with the restraining material 30, and the pressing force is applied to the restraining material 30. As shown in FIG. A Q will be given.

If the strength of the end portion of the buckling restraint brace to which the external force is directly input during an earthquake is weak, and therefore only the end portion of the core material 10 is buckled, the compressive force N is not transmitted to the entire area of the core material 10, and the core material 10 Due to the inability of the buckling of the higher order modes to occur in its entirety, it will develop much less yield strength than the initial yield strength of the buckling restraint brace.

In this regard, in the illustrated buckling restraint brace 100 , the end reinforcing members 60 are inserted through both ends of the restraining members 30 and are welded to the inner surfaces of the restraining members 30 so that both ends of the pair of restraining members 30 are Therefore, the high-strength end structure of the pair of restraining members 30 strengthens the ends of the buckling restraint brace 100 including the core member 10 . be done. As a result, the core material 10 can smoothly undergo high-order mode buckling in the direction of its weak axis not only at its ends but also over its entire area.

The local yield strength of the restraining member 30 is set so as not to cause local failure against the pressing force Q acting locally.

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 10a: wide surface 11: narrow portion 12: wide portion 12a: bolt hole 13: joining plate 13a: bolt hole 14: slit 15: projection 17: spacer 18: reinforcing plate 20: unbonded material 20a: projection hole 30: Restraining material (square steel pipe)
30a: Projection hole 50: Stiffener 60: End reinforcement (shaped steel, channel steel)
100: Buckling restraint brace N: Axial force (compressive force)
Q: Pressing force

Claims (5)

A plate-like core material made of steel,
a pair of restraining members made of rectangular steel pipes arranged to face the two wide surfaces of the core member;
Having an unbonded material interposed between the core material and the restraining material,
A buckling restrained brace, characterized in that end stiffeners are passed through the interior of both ends of the restraint and bonded to the inner surface of the restraint. 2. A buckling restrained brace according to claim 1, wherein said end stiffeners are channel steel. The length of the end reinforcing member is set to a length of 2 to 3 wavelengths in wavy deformation, which is buckling of a higher-order mode occurring in the weak axis direction of the core member. A buckling restrained brace according to claim 1 or 2. A pair of joining plates are fixed to both ends of the core material and are joined to other members perpendicular to the wide surface,
A reinforcing plate is fixed to the pair of joint plates, and an end of the restraint member is accommodated in a space formed by the wide surface, the pair of joint plates, and the reinforcing plate, A buckling restrained brace according to any one of claims 1-3. A pair of stiffeners connect both sides of the pair of restraint members on the sides of the core member,
A buckling restrained brace according to any preceding claim, wherein the core is surrounded by the pair of restraints and the pair of stiffeners.

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