JP7610964B2 - Buckling Restrained Brace - Google Patents

Description

This invention relates to a buckling restraint brace that is incorporated into a structure to absorb vibration energy and dampen vibration during earthquakes and other events.

Patent Document 1 discloses a buckling restraint brace that includes a core member with joints at both ends of the plate-shaped portion for joining to other members, and restraint members arranged opposite each face of the plate-shaped portion perpendicular to the weak axis direction, in which an insert plate is provided between the plate-shaped portion and the restraint member in contact with the restraint member, and an unbonded material is positioned between the insert plate and the core member.

JP 2016-117995 A

In this type of buckling restraint brace, the process of attaching the unbonded material to, for example, the core material involves bonding together multiple pieces of unbonded material that are narrower than the core material.

However, if the multiple unbonded materials overlap when they are bonded together, the thickness of the unbonded material at the overlapping points will be different from other points, and the buckling restrained brace that is manufactured may not perform as designed. Here, the unbonded material functions as a clearance that allows the core material to undergo wavy deformation when an impact is applied to the buckling restrained brace, and also has the function of reducing friction with the restraining material during this deformation.

In view of the above circumstances, this invention aims to prevent the occurrence of locations where the thickness of the unbonded material differs from the designed thickness, and to allow the buckling restraint brace to exert the vibration control effect as designed.

The buckling restraint brace of this invention is a buckling restraint brace comprising a core material having joints at both ends of the plate-shaped portion for joining to other members, restraint materials arranged opposite each face perpendicular to the weak axis direction of the plate-shaped portion, and unbonded materials arranged between the core material and the restraint materials, characterized in that the unbonded materials are made up of multiple unbonded materials, and the multiple unbonded materials are attached with gaps between each other in the short side direction of the core material.

With the above configuration, even if the unbonded material is not attached linearly in the process of attaching it to the core material, causing some distortion, the unbonded materials are attached with gaps between them in the short side direction of the core material, so that overlapping of the unbonded materials can be avoided. This prevents the unbonded material from having a thickness that differs from the design thickness in places, allowing the buckling restraint brace to exert the vibration control effect as designed.

In addition, even if there is a gap, the unbonded material can function as a clearance that allows the core material to undergo wavy deformation when an impact is applied to the buckling restraint brace, so it can exhibit performance comparable to that of a configuration without a gap. Furthermore, when the impact causes wavy deformation in the core material, the unbonded material is pushed by the apex of the wavy deformation of the core material and is partially pushed out toward the gap, reducing friction between the components at the gap and promoting deformation of the core material.

The unbonded material may be located at the end of the core material in the short side direction. Here, if the unbonded material is attached only to the center of the core material, for example, when the restraining material is placed on the unbonded material in a subsequent process, the restraining material placed thereon may become unstable like a balance, and the clearance to be secured by the unbonded material may not be the designed value. By positioning the unbonded material at the end of the short side direction of the core material, such clearance problems can be avoided.

The unbonded material may be applied so as to occupy an area of 20% or more and 95% or less of the effective width of the restraining material in the short side direction. By reducing the proportion of the unbonded material in the effective width of the restraining material in the short side direction, the amount of unbonded material used can be reduced, thereby reducing costs.

An insert plate may be disposed between the core material and the restraint material, and the unbonded material may be located between the insert plate and the core material.

The present invention has the effect of preventing the occurrence of locations where the thickness of the unbonded material differs from the designed thickness, and enabling the buckling restraint brace to exert the vibration control effect as designed.

1A and 1B are schematic longitudinal cross-sectional views showing a buckling restraint brace according to an embodiment, in which FIG. 1A shows the completed state and FIG. 1B shows the disassembled state. 2A is a perspective view showing the buckling restraint brace of FIG. 1, and FIG. 2B is a perspective view showing the core material. Figure 3A is an explanatory diagram showing how the stiffening force of the core material in the buckling restraint brace of Figure 1 is received by the restraint material and the inner plate, and Figure 3B is an explanatory diagram showing the relationship between the deformation of the core material in the weak axis direction and the stiffening force. 1 is an explanatory diagram showing an effective attachment length of a tape-shaped unbonded material to a restraint material. FIG. FIG. 13 is a schematic longitudinal cross-sectional view of an embodiment of a buckling restraint brace with an insert plate in an exploded state.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in Figures 1(A), 1(B), 2(A), and 2(B), the buckling restrained brace 1 of this embodiment includes a core material 11, restraining materials 12, unbonded materials 14, 14, width-direction stiffeners 15, and a reinforcing plate 16. In this embodiment, the unbonded material 14 is in the form of a tape, but a sheet-like or plate-like unbonded material can also be used.

The core material 11 is made of, for example, a steel plate, and has joints 11b at both ends of the plate-shaped portion 11a. The plate-shaped portion 11a has a constant width, and the joints 11b at both ends are wider than the plate-shaped portion 11a. The cross section of the joint 11b perpendicular to the longitudinal direction of the plate-shaped portion 11a is made to be approximately H-shaped, and a splice plate can be placed on this joint 11b to join it to another member. Holes through which bolts for the above-mentioned joining are inserted are formed in the parts of the joint 11b that will become the flange portion and the web portion. In the boundary region from the plate-shaped portion 11a to the joint 11b, the width of the plate-shaped portion 11a gradually widens in a curved shape, changing in shape to form the web portion of the joint 11b.

The restraining member 12 is made of a square steel pipe with a rectangular cross section. This square steel pipe has a first surface portion which is the long side of the rectangle, and a second surface portion which is the short side. The first surface portion of the restraining member 12 is arranged to face each surface perpendicular to the weak axis direction (thickness direction of the core material 11) of the plate-shaped portion 11a of the core material 11. Both longitudinal ends of the restraining member 12 extend beyond the curved spreading portion and reach the web portion at the joint portion 11b. In addition, the square steel pipe has a corner portion with an R region (curved region) at the intersection of each surface portion.

In addition, a pin-shaped anti-slip protrusion 11c that protrudes from both sides of the core material 11 is provided at the center of the long side direction and the center of the short side direction of the core material 11. This anti-slip protrusion 11c is inserted into a hole provided in the first surface portion that is the inside of the restraint material 12 when the buckling restraint brace 1 is assembled. The anti-slip protrusion 11c is made of a steel material such as a steel rod, and is, for example, inserted into a hole provided in the core material 11 and joined.

The widthwise stiffener 15 is made of steel plate and restrains deformation of the core material 11 in the widthwise direction (within the structural plane). This widthwise stiffener 15 is stretched across the second surface portions of the restraining materials 12, 12 and is fixed to the restraining materials 12, 12 by a welded portion 15a. In addition, a U-shaped cut portion 15b with an opening on the end side is formed at the end of the widthwise stiffener 15, and within this cut portion 15b is located an area where the width of the plate-shaped portion 11a gradually expands in a curved shape.

The reinforcing plate 16 is made of a steel plate and is placed between the flanges of the joint 11b of the core material 11 and welded to the flanges. The reinforcing plate 16 is arranged so as to overlap the unstiffened section (the cut portion 15b).

As shown in Figures 3(A) and 3(B), the tape-like unbond material 14 is provided between the plate-like portion 11a of the core material 11 and the restraining material 12, and when the plate-like portion 11a is subjected to a compressive force, a wavy deformation occurs with the thickness of the unbond material 14 as a clearance. The unbond material 14 is made of, for example, butyl rubber. In this embodiment, two tape-like unbond materials 14 are arranged. The tape-like unbond material 14 only needs to have a length up to a position just before the point where the width of the plate-like portion 11a gradually widens in a curved shape.

The two tape-like unbonded materials 14, 14 are attached to the core material 11 in the short side direction with a gap G between them. The tape-like unbonded material 14 is also located on the end side of the core material 11 in the short side direction.

When the tape-shaped unbonded material 14 is attached to the restraining material 12, for example, as shown in FIG. 4, the tape-shaped unbonded material 14 may be attached so that a part of the tape-shaped unbonded material 14 overlaps the rounded area (horizontal length R) of the corner of the restraining material 12. However, the effective width of the attachment is the X-length portion on the flat plate portion excluding the rounded area. Here, the unbonded material 14 that overlaps the above-mentioned rounded area is not included in the effective length of the attachment, so the attachment width ratio of the two sheets of unbonded material 14 to the effective width of the restraining material 12 of width A (the length of the flat plate portion (A-2R)) is expressed as 2X/(A-2R). The tape-shaped unbonded material 14 may also be attached to the core material 11 side. In this case, the above-mentioned X-length portion that is somewhat removed from the end of the core material 11 becomes the effective length of the unbonded material 14. Note that the tape-shaped unbonded material 14 with release paper attached to one side may be attached to the other side, and the release paper may be left attached.

In the above-mentioned buckling restraint brace 1, the tape-like unbonded material 14 is applied to occupy an area of 20% or more and 95% or less of the effective width in the short side direction of the restraint material 12. In other words, 20%≦2X/(A-2R)≦95%. There may be three or more pieces of tape-like unbonded material 14, and in such a configuration, two or more gaps G are formed. When there are three pieces of tape-like unbonded material 14, the above "2X" is changed to "3X". It is not limited to the fact that the effective width of application of the three pieces of tape-like unbonded material 14 is all the same.

With the above configuration, even if the tape-like unbonded material 14 is not attached linearly in the process of attaching it to the core material 11 or the restraining material 12, causing some distortion, the tape-like unbonded material 14 is attached in the short side direction of the core material 11 with a gap G between each other, so that overlapping of the tape-like unbonded material 14 can be avoided. This prevents the thickness of the unbonded area from differing from the design thickness in places, allowing the buckling restraint brace 1 to exert the vibration control effect as designed.

Even if the above-mentioned gap G exists, the tape-shaped unbonded material 14 can function as a clearance that allows the core material 11 to undergo wavy deformation when an impact is applied to the buckling restraint brace 1, and therefore can exhibit performance comparable to that of a configuration without gap G. In addition, when two pieces of tape-shaped unbonded material 14 were positioned at the ends of the core material 11 and a gap G was formed between them, and a test was conducted with 2X/(A-2R) = 20%, performance (hysteresis curve) comparable to that of a configuration without gap G was confirmed, and it can be inferred that even when 20% < 2X/(A-2R), performance comparable to that of a configuration without gap G exists.

In addition, when the impact causes a wavy deformation in the core material 11, the tape-shaped unbonded material 14 is pushed at the peak of the wavy deformation of the core material 11 and partially pushed out toward the gap G, thereby reducing friction between the components at the gap G and promoting deformation of the core material 11. The pushing out of the tape-shaped unbonded material 14 toward the gap G was also confirmed by testing.

Here, if the tape-like unbonded material 14 is attached only to the center of the core material 11, for example, when the restraining material 12 is placed on the tape-like unbonded material 14 in a subsequent process, the restraining material 12 may become unstable like a balance, and the clearance that the unbonded material 14 is intended to secure may not be the designed value. In contrast, if the tape-like unbonded material 14 is positioned on the end side of the short side of the core material 11, this problem can be avoided. Note that even in a structure in which the tape-like unbonded material 14 is attached only to the center of the core material 11, it is possible to secure the designed clearance by welding the restraining material 12 and the width-direction stiffener 15 to each other through a removable spacer on the end side of the core material 11.

In addition, as described above, the tape-shaped unbonded material 14 can be reduced by up to 20% of the effective width of the restraint material 12 in the short side direction, thereby reducing the cost of the buckling restraint brace 1.

The tape-shaped unbonded material 14 does not necessarily have to be placed between the core material 11 and the restraint material 12. In another embodiment of the buckling restraint brace 1A shown in FIG. 5, an insert plate 13 is placed between the core material 11 and the restraint material 12, and the tape-shaped unbonded material 14 is located between the insert plate 13 and the core material 11. The tape-shaped unbonded material 14 is attached to the surface of the core material 11 or the insert plate 13 facing the core material 11. The insert plate 13 is fixed to the restraint material 12 by welding.

The restraining material 12 is not limited to steel pipes, but may be, for example, channel steel filled with mortar or concrete. The joint 11b of the core material 11 is not limited to an H-shape, but may be a cross shape, etc.

Although an embodiment of the present invention has been described above with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications and variations can be made to the illustrated embodiment within the same scope as the present invention or within an equivalent scope.

1: Buckling restrained brace 1A: Buckling restrained brace 11: Core material 11a: Plate-shaped portion 11b: Joint portion 11c: Anti-slip protrusion 12: Restraint material 13: Insertion plate 14: Unbonded material 15: Width direction stiffener 15a: Welded portion 15b: Cut portion 16: Reinforcing plate G: Gap

Claims (4)

A buckling restraint brace comprising a core material having joints at both ends of a plate-shaped portion for joining to other members, restraint materials arranged opposite planar regions which are each surface perpendicular to the weak axis direction of the plate-shaped portion, and unbonded materials arranged between the planar regions and the restraint materials, wherein a plurality of unbonded materials are affixed to the planar region where a single piece of unbonded material can be affixed with gaps between them in the short side direction of the planar region . The buckling restraint brace of claim 1, characterized in that the unbonded material is located on the end side of the short side of the core material. The buckling restraint brace according to claim 1 or 2, characterized in that the unbonded material is attached to occupy an area of 20% or more and 95% or less of the effective width of the restraint material in the short side direction. The buckling restraint brace according to any one of claims 1 to 3, characterized in that an insert plate is disposed between the core material and the restraint material, and the unbonded material is located between the insert plate and the core material.

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