Buckling restraint brace

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

Technical Field

[0001] The present invention relates to a buckling restraining brace.

Background Art

[0002] Conventionally, as a brace for forming a building structure (column-beam structure, roof structure, etc.), a buckling restraining brace with buckling prevention measures has been applied. As the buckling restraining brace, there are various stiffening forms, such as a form in which the periphery of a steel core material is stiffened only with steel plates, a form in which the periphery of a steel core material is stiffened with RC (Reinforced Concrete), and a form in which the periphery of a steel core material is coated with steel and mortar.

[0003] Here, Patent Document 1 proposes a buckling restraining brace in which a core material is restrained by a restraining member formed of a pair of square steel pipes, and the buckling restraining brace does not cause local failure in the restraining member receiving the pressing force from the core material. Specifically, it is a buckling restraining brace including a core material having joints for joining to other members at both ends of a plate-like portion, and a restraining member disposed facing each surface orthogonal to the weak axis direction of the plate-like portion.

[0004] In this buckling restraining brace, an insertion plate that contacts the restraining member is provided between the plate-like portion and the restraining member, and the restraining member made of a square steel pipe has corners having curved surface regions at the intersection portions of its respective surface portions. A welding portion for fixing the restraining member and the insertion plate is provided between the surface of the insertion plate on the side contacting the restraining member and the corner of the restraining member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] According to the buckling restraint brace described in Patent Document 1, it becomes easy to use a member such as a ready-made square steel pipe as a restraint material, and it is possible to suppress local failure of the restraint material receiving a pressing force from the core material without causing a cost increase.

[0007] By the way, the buckling restraint brace is incorporated into the building structure by being bolted or the like to connection jigs such as brackets and gusset plates provided at the corner portions or the like of the building structure at both ends thereof. When the building structure deforms during an earthquake, an external force such as a horizontal force during the earthquake enters the end of the buckling restraint brace through the bracket or the like, and the external force is transmitted as a compressive force or the like from the end of the core material to the entire area thereof, so that the entire area of the core material undergoes plastic deformation, and the energy absorption performance during the earthquake is exhibited. More specifically, when a compressive force acts on the core material, high-order mode buckling (wavy deformation) occurs in the weak axis direction over the entire area thereof, and by buckling the entire core material as evenly as possible, the overall plastic deformation performance of the buckling restraint brace can be exhibited.

[0008] On the other hand, if the strength of the end of the buckling restraint brace where the external force is directly input during an earthquake is weak, and thus only the end of the core material buckles, the compressive force or the like is not transmitted to the entire area of the core material, and the core material cannot undergo high-order mode buckling over the entire area, resulting in the ability to exhibit only a strength much smaller than the initial yield strength of the buckling restraint brace. Therefore, the reinforcement of the end of the buckling restraint brace is extremely important from the viewpoint of ensuring that the buckling restraint brace exhibits the initial energy absorption performance. Note that Patent Document 1 does not specifically mention the reinforcement of the end of this buckling restraint brace.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a buckling restraint brace having high strength at the end and capable of smoothly causing high-order mode buckling in the weak axis direction over the entire area of the core material.

Means for Solving the Problems

[0010] To achieve the above object, one aspect of the buckling restraint brace according to the present invention is as follows. a steel plate-shaped core material, a pair of restraint members made of square steel pipes arranged so as to face two wide surfaces of the core material, and an unbonded material interposed between the core material and the restraint members, characterized in that end reinforcing members are inserted into the interiors of both ends of the restraint members and joined to the inner surfaces of the restraint members.

[0011] According to this aspect, in a buckling restraint brace in which two wide surfaces of a steel plate-shaped core material are restrained by a pair of restraint members made of square steel pipes, by inserting end reinforcing members into the interiors of both ends of the restraint members and joining them to the inner surfaces of the restraint members, the end strength of the buckling restraint brace can be made high-strength. And, by effectively reinforcing the ends of the pair of restraint members, the ends of the core material sandwiched by the pair of restraint members are reinforced, and the core material can smoothly generate buckling in the higher-order mode (wavy deformation) in the weak axis direction not only at its ends but also over its entire area.

[0012] Here, the "end reinforcing member" includes not only pieces of shaped steel materials such as angle steel, channel steel, and H-shaped steel, but also square steel pipes having a smaller cross-sectional dimension than the square steel pipes forming the restraint members.

[0013] Further, the unbonded material is formed of an elastic material having deformation performance such as butyl rubber. By interposing this unbonded material between the wide surface of the core material and the restraint member, using the thickness of the unbonded material as a clearance, it becomes possible to generate buckling in the higher-order mode within this clearance when the core material receives a compressive force.

[0014] In the core material, slits may be provided on the wide surfaces of the core material in order to effectively generate buckling in the higher-order mode in the weak axis direction. And, since the strength in the strong axis direction of the core material becomes weak by providing slits on the wide surfaces in this way, spacers may be inserted into the slits on the wide surfaces as necessary.

[0015] Also, another aspect of the buckling restraint brace according to the present invention is that the end reinforcing member is a channel steel.

[0016] According to this aspect, by applying channel steel as the end reinforcing member, regardless of the position of the seam of the square steel pipe, it becomes possible to easily insert and join the channel steel from the end of the square steel pipe into its interior.

[0017] Also, in another aspect of the buckling restraint brace according to the present invention, the length of the end reinforcing member is set to a length of 2 to 3 wavelengths in a wavy deformation that is buckling of a higher-order mode occurring in the weak axis direction of the core material.

[0018] According to this aspect, since the length of the end reinforcing member is set to a length of 2 to 3 wavelengths in a wavy deformation that is buckling of a higher-order mode occurring in the weak axis direction of the core material, it becomes possible to smoothly cause a wavy deformation on the central side of the core material while sufficiently reinforcing the end of the buckling restraint brace.

[0019] Also, in another aspect of the buckling restraint brace according to the present invention, a pair of joint plates that are joined to other members perpendicular to the wide surface are fixed to both ends of the core material, a reinforcing plate is fixed to the pair of joint plates, and the end of the restraint material is accommodated in a space formed by the wide surface, the pair of joint plates, and the reinforcing plate.

[0020] According to this aspect, a pair of joint plates perpendicular to the wide-width surface are fixed at both ends of the core material, a reinforcing plate is fixed to the pair of joint plates, and the end of the restraint material is accommodated in the space formed by the wide-width surface, the pair of joint plates, and the reinforcing plate. As a result, combined with the fact that the end of the restraint material is reinforced by the end reinforcing material, a buckling restraint brace with a high-strength end structure is formed. Here, examples of the other member to which the joint plate is joined include connection fixtures such as brackets and gusset plates that project into the plane from the corner parts of the building structure and the like. Further, when the end of the core material is used as the web, the pair of joint plates perpendicular to this web become a pair of flanges.

[0021] Further, another aspect of the buckling restraint brace according to the present invention is On the side of the core material, a pair of supplementary stiffening members connect both sides of the pair of restraint materials, and the core material is characterized by being surrounded by the pair of restraint materials and the pair of supplementary stiffening members.

[0022] According to this aspect, since a pair of supplementary stiffening members connect both sides of the pair of restraint materials on the side of the core material, deformation in the width direction (strong axis direction) of the core material can be restrained by the supplementary stiffening members.

[0023] Further, the buckling restraint brace according to the present invention may be in a form in which an insertion plate is interposed between the unbonded material and the restraint material. According to this form, for example, since a steel insertion plate is interposed between the unbonded material and the restraint material, the pressing force due to the buckling of the higher-order mode in the weak axis direction of the core material directly acts on the restraint material, and it is possible to effectively suppress the local failure of the restraint material.

Effects of the Invention

[0024] As can be understood from the above description, according to the buckling restraint brace of the present invention, it is possible to provide a buckling restraint brace with high strength at the end and guaranteed buckling of the higher-order mode throughout the core material.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

[0026] Hereinafter, a buckling restraint brace according to an embodiment will be described with reference to the accompanying drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals, and redundant explanations may be omitted.

[0027] [Buckling Restraint Brace According to Embodiment] With reference to FIGS. 1 to 5, an example of a buckling restraint brace according to an embodiment will be described. Here, FIG. 1 is an exploded perspective view of an example of a buckling restraint brace according to the embodiment, and FIG. 2 is a longitudinal sectional view in the direction orthogonal to the axis of the buckling restraint brace in the state before assembly, regarding the end of the buckling restraint brace according to the embodiment. Further, FIG. 3 is a perspective view of an example of a buckling restraint brace according to the embodiment, and FIG. 4 is a longitudinal sectional view in the direction orthogonal to the axis of the buckling restraint brace in the assembled state, regarding the end of the buckling restraint brace according to the embodiment.

[0028] The buckling restraint brace 100 includes a core material 10, a pair of restraint materials 30 disposed so as to face two wide surfaces 10a of the core material 10, and an unbonded material 20 interposed between the core material 10 and the restraint materials 30. Here, in addition to the illustrated example, a form in which an insertion plate is interposed between the unbonded material 20 and the restraint materials 30 may also be used.

[0029] The core material 10 is preferably formed of a steel material with a low yield point, such as an SN material (rolled steel for building structures) or an LYP material (extra-low yield point steel). By applying the core material 10 made of these materials, the earthquake energy absorption performance due to the yield of the core material 10 is improved.

[0030] The core material 10 is formed of an elongated steel plate, has a narrow-width portion 11 with a relatively narrow width of the wide surface 10a on the central side in its longitudinal direction, and has a wide-width portion 12 with a relatively wide width of the wide surface 10a on the end side in its longitudinal direction.

[0031] Since the core material 10 has the narrow-width portion 11 on the central side in its longitudinal direction and the wide-width portion 12 on the end side in its longitudinal direction, the narrow-width portion 11 on the central side can be made into a region where plasticization is easy, and furthermore, the plasticization region can be limited to the narrow-width portion 11 on the central side.

[0032] At the central position of the narrow-width portion 11 of the core material 10, steel cylindrical protrusions 15 project from the two wide surfaces 10a of the narrow-width portion 11. The protrusions 15 are joined to the wide surfaces 10a of the narrow-width portion 11 by welding or the like.

[0033] In addition, elongated slits 14 are provided on both sides of the protrusions 15 of the narrow-width portion 11 of the core material 10, and steel spacers 17 are inserted into the slits 14 in the X1 direction.

[0034] The slits 14 are pores for adjusting the yield strength of the core material 10, and the spacers 17 function as internal deformation prevention materials for preventing the core material 10 from deforming internally (deforming in the strong axis direction) due to the provision of the slits 14. The spacers 17 inserted into the slits 14 are position-regulated by the pair of restraint materials 30.

[0035] At both ends of the core material, on the wide-width portions 12, there are joined, by welding or the like, a pair of joining plates 13 made of steel plates that are joined to other members perpendicular to the wide-width surfaces 10a.

[0036] The wide-width portions 12 and the joining plates 13 are respectively provided with bolt holes 12a and 13a, which are aligned with the bolt holes of connection jigs (other members) such as brackets and gusset plates that project into the plane from the corner portions or the like of a building structure (not shown), and are bolted together.

[0037] A reinforcing plate 18 made of a steel plate is joined to the pair of joining plates 13 by welding or the like, and the end portion of the restraint material 30 is accommodated in the space formed by the wide-width portion 12 of the core material 10, the pair of joining plates 13, and the reinforcing plate 18.

[0038] The unbonded material 20 is inserted between the narrow-width portion 11 of the core material 10 and the restraint material 30. Using the thickness of the unbonded material 20 as a clearance, when the building structure deforms, a compressive force acts on the core material 10, causing buckling (wavy deformation) of the higher-order mode in the out-of-plane direction (weak axis direction) in the narrow-width portion 11.

[0039] As the unbonded material 20, for example, an elastic material such as butyl rubber is applied. Also, at the central position in the longitudinal direction of the unbonded material 20, there is provided a protrusion hole 20a into which the protrusion 15 of the core material 10 fits.

[0040] The restraint material 30 is formed of a rectangular steel pipe in cross-sectional view, and the side surface corresponding to the long side of the rectangle is in contact with the unbonded material 20. Also, on the side surface of the restraint material 30 that is in contact with the unbonded material 20, there is provided a protrusion hole 30a into which the protrusion 15 of the core material 10 fits.

[0041] On the side of the core material 10, both sides of the pair of restraint materials 30 (the side surfaces corresponding to the short sides of the rectangle) are connected by a pair of stiffening materials 50 made of steel plates by welding or the like, and the core material 10 is surrounded by the pair of restraint materials 30 and the pair of stiffening materials 50.

[0042] As shown in Fig. 1, inside both ends of the restraint member 30, end reinforcing members 60 are inserted in the X2 direction and are 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 both ends of the buckling restraint brace 100 including the core member 10 are reinforced by the reinforcement of both ends of the pair of restraint members 30.

[0043] Here, the end reinforcing member 60 can be formed by a piece of shaped steel such as an angle steel, a channel steel, an H-shaped steel, or a piece of a square steel pipe with a smaller cross-sectional dimension than the square steel pipe forming the restraint member 30. However, from the viewpoint of being able to be easily inserted from the end of the square steel pipe 30 into its interior and welded regardless of the position of the seam of the square steel pipe 30, the application of the channel steel in the illustrated example is preferable.

[0044] Further, the length t (see Fig. 1) of the end reinforcing member 60 is set to a length of 2 to 3 wavelengths in the wavy deformation that is the buckling of the higher mode occurring in the weak axis direction of the core member 10. By setting the length of the end reinforcing member 60 to the above length, it becomes possible to smoothly generate a wavy deformation on the central side of the core member 10 while sufficiently reinforcing the end of the buckling restraint brace 100.

[0045] In this way, by reinforcing both ends of the restraint member 30 with the end reinforcing members 60, it is possible to cause buckling of the higher mode in the entire area of the core member 10 with the minimum necessary reinforcement without increasing the overall plate thickness of the restraint member 30, which also leads to suppression of the increase in the manufacturing cost of the buckling restraint brace 100.

[0046] Next, with reference to Fig. 5, the buckling of the higher mode occurring in the weak axis direction of the core member 10 will be described.

[0047] The buckling restraint brace 100 is incorporated into the building structure by bolt connection or the like to connection fixtures provided at the corner portions or the like of the building structure at both its ends. When the building structure deforms during an earthquake, an external force such as a horizontal force during the earthquake enters the end of the buckling restraint brace 100 through the connection fixture, and the external force is transmitted as a compressive force N from the end of the core material 10 to its entire area. As a result, the entire area of the core material 10 undergoes plastic deformation, and the energy absorption performance during an earthquake is exhibited. In other words, when a compressive force N acts on the core material 10, higher-order mode buckling (wavy deformation) occurs in the weak axis direction over the entire area of the core material 10, and by causing the entire core material 10 to buckle as evenly as possible, the overall plastic deformation performance of the buckling restraint brace 100 can be exhibited.

[0048] As shown in FIG. 5B, higher-order mode buckling occurs due to the compressive force N acting on the core material 10, and the peaks of the wavy deformation due to the buckling come into contact with the restraint material 30, applying a pressing force Q to the restraint material 30.

[0049] If the strength of the end of the buckling restraint brace where the external force is directly input during an earthquake is weak, and thus only the end of the core material 10 buckles, the compressive force N cannot be transmitted to the entire area of the core material 10, and the core material 10 cannot undergo higher-order mode buckling over its entire area. As a result, only a strength much smaller than the initial yield strength of the buckling restraint brace can be exhibited.

[0050] Regarding this point, in the illustrated buckling restraint brace 100, end reinforcing members 60 are inserted into the interiors of both ends of the restraint material 30 and are welded to the inner surface of the restraint material 30. Since both ends of the pair of restraint materials 30 are sufficiently reinforced to form a high-strength end structure, the high-strength end structure of the pair of restraint materials 30 reinforces the end of the buckling restraint brace 100 including the core material 10. As a result, it becomes possible to smoothly cause higher-order mode buckling in the weak axis direction of the core material 10 not only at its end but also over its entire area.

[0051] The local yield strength of the restraint material 30 is set so as not to cause local fracture with respect to the locally acting pressing force Q.

[0052] Other embodiments may also be possible in which other components are combined with the configurations and the like described in the above embodiments, and the present invention is not limited to the configurations shown here. In this regard, it is possible to make changes without departing from the spirit of the present invention, and it can be appropriately determined according to the application form.

Explanation of Reference Numerals

[0053] 10: Core material 10a: Wide surface 11: Narrow portion 12: Wide portion 12a: Bolt hole 13: Bonding plate 13a: Bolt hole 14: Slit 15: Protrusion 17: Spacer 18: Reinforcing plate 20: Unbonding material 20a: Protrusion hole 30: Restraining material (square steel pipe) 30a: Protrusion hole 50: Stiffening material 60: End reinforcing material (section steel, channel steel) 100: Buckling restraint brace N: Axial force (compressive force) Q: Pressing force

Claims

Claim 1 a steel plate-shaped core material, a pair of restraint members made of square steel pipes disposed so as to face two wide surfaces of the core material, and an unbonded material interposed between the core material and the restraint members, wherein an end reinforcing member is inserted into the inside of both ends of the restraint member and joined to the inner surface of the restraint member, the buckling restraint brace is characterized in that the length of the end reinforcing member is set to a length of 2 to 3 wavelengths in a wavy deformation which is buckling of a higher-order mode occurring in the weak axis direction of the core material. Claim 2 The buckling restraint brace according to claim 1, wherein the end reinforcing member is a channel steel. Claim 3 a pair of joint plates which are joined to other members orthogonally to the wide surfaces are fixed to both ends of the core material, a reinforcing plate is fixed to the pair of joint plates, and the end of the restraint member is housed in a space formed by the wide surface, the pair of joint plates, and the reinforcing plate, the buckling restraint brace according to claim 1 or 2. Claim 4 on the side of the core material, a pair of supplementary stiffening members connect both sides of the pair of restraint members, the buckling restraint brace according to any one of claims 1 to 3, wherein the core material is surrounded by the pair of restraint members and the pair of supplementary stiffening members.

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