JP7812225B2 - Buckling Restrained Brace - Google Patents

Description

This invention relates to a buckling restraint brace that comprises a core member having joints on both longitudinal ends of an elongated plate-like body, and a pair of restraint members arranged opposite each face of the core member.

Patent Document 1 discloses a buckling-restrained brace that includes a core material and reinforced concrete as a buckling-restrained material that is arranged around the core material and unbonded to the core material, with the reinforcement ties in the reinforced concrete being more densely arranged at positions corresponding to the cross-sectional defects than in other areas.

Patent Document 2 discloses a buckling restraint brace that has a core member and a pair of restraint members arranged along both sides of the core member. Each of the pair of restraint members has a channel steel member that is open on the core member side, and mortar or concrete filled within the channel steel member.

JP 2011-168984 A JP 2009-249833 A

However, the buckling restrained brace disclosed in Patent Document 1 has the disadvantage that it is not easy to manufacture because it has a structure in which reinforcing bars surround the core material. On the other hand, it is difficult to adopt the reinforcement structure shown in Patent Document 1 for the buckling restrained brace disclosed in Patent Document 2.

The objective of this invention is to provide a buckling-restrained brace, in which restraint members are placed opposite each side of the core member, with a simple structure that maintains high strength.

The buckling restrained brace of this invention is a buckling restrained brace having a core member having joints on both ends of the longitudinal direction of an elongated plate-like body, and a pair of restraint members arranged opposite each face of the core member,
The restraining material is:
a box-shaped member having an opening formed on the side where the core material is located and recessed portions formed at the center of both end portions overlapping with the joint portion so as to avoid interference with the joint portion;
a hardened member filled in the box-shaped member and hardened;
a metal reinforcement member disposed within the hardened member;
The present invention is characterized by comprising:

With the above configuration, the metal reinforcing material is disposed within the stiffening member, thereby increasing the strength of the buckling restraint brace. Furthermore, rather than surrounding the core material with metal reinforcing material, the core material is sandwiched between the metal reinforcing material, resulting in a simple structure and easy manufacturing.

The metal reinforcing member may have end reinforcing portions located outside the recesses at each end of the box-shaped member, and a central reinforcing portion located at a non-end portion of the box-shaped member. This can reduce cracking of the hardened member located at each end of the box-shaped member during transportation of the buckling restraint brace, compared to a configuration in which the metal reinforcing member only has the central reinforcing portion.

The end reinforcement portion and the center reinforcement portion may be integrated. This requires, for example, cutting a portion of the center of the longitudinal end of the metal reinforcement material to create a concave shape, but has the advantage that only one piece of metal reinforcement material needs to be placed on each box-shaped member.

Alternatively, the end reinforcement portion and the central reinforcement portion may be separate bodies, with the end reinforcement portion extending toward the central reinforcement portion and overlapping each other. In this case, multiple rectangular metal reinforcement members of a certain shape can be combined and placed in the box-shaped member, eliminating the need to machine the metal reinforcement members into recesses as described above.

Alternatively, two strip-shaped metal reinforcing members, each with the same width as the end reinforcing member and the central reinforcing member, may be placed adjacent to each other. This eliminates the need for recessed processing of the metal reinforcing members as described above, and simplifies manufacturing, as it is sufficient to place two strip-shaped metal reinforcing members of the same type inside the box-shaped member.

Another metal reinforcing member may be provided straddling the two strip-shaped metal reinforcing members at a non-end portion of the box-shaped member. In this way, the two strip-shaped metal reinforcing members are joined by the other metal reinforcing member, further improving the bearing strength of the restraint member.

If the distance between the surface of the hardened member facing the core material and the end-side reinforcement portion is D1 and the distance between the surface of the hardened member facing the core material and the center-side reinforcement portion is D2, D1 < D2 may be satisfied. This improves the bending rigidity of the center side of the restraining member while suppressing damage to the hardened member on each end side of the restraining member.

The central reinforcement portion may have a wave shape that repeatedly approaches and moves away from the core material in the longitudinal direction of the core material, and the peak of the amplitude of the wave shape of the central reinforcement portion may face the predicted peak position of the amplitude of the wave-like deformation due to compression of the core material. This improves the strength of the stiffened member relative to the predicted peak position of the core material (improved local strength) and improves the bending rigidity of the core material at locations other than the predicted peak position.

This invention has various advantages, such as improving the strength of buckling restraint braces.

FIG. 1 is a perspective view showing the appearance of a buckling restraint brace according to an embodiment. FIG. 2 is a schematic cross-sectional view of the buckling restrained brace of FIG. FIG. 2 is an exploded view illustrating the buckling restraint brace of FIG. 1. 2 is an explanatory diagram showing a part of the manufacturing process of the restraint material of the buckling restraint brace of FIG. 1. FIG. 2 is an exploded explanatory view showing a modified example of the buckling restraint brace of FIG. 1. 5A is a schematic cross-sectional view of the end side of the buckling restrained brace of FIG. 5, and FIG. 5B is a schematic cross-sectional view of the center side of the same buckling restrained brace. FIG. 10 is an exploded view illustrating a buckling restraint brace according to another embodiment. FIG. 8 is an exploded explanatory view showing a modified example of the buckling restraint brace of FIG. 7. FIG. 10 is an exploded view illustrating a buckling restraint brace according to another embodiment. FIG. 10 is an exploded explanatory view showing a modified example of the buckling restraint brace of FIG. FIG. 10 is an explanatory diagram showing a buckling restraint brace according to another embodiment.

(Embodiment 1)
The buckling restrained brace 1 of this embodiment includes a core member 2 and a pair of restraint members 3 arranged to sandwich the core member 2, as shown in Figures 1 and 2.

The core material 2 comprises an elongated steel plate 21 and joints 22 located on both ends of the plate 21. It is fixed to the building frame with bolts inserted through bolt holes formed in the joints 22. The joints 22 have a generally cross-shaped cross section, with plate pieces 22b welded orthogonally to extensions 22a extending from both ends of the plate 21. The portion of the plate piece 22b that does not have the bolt holes and extends toward the center of the plate 21 protrudes lower than the portion of the plate piece 22b where the bolt holes are formed.

As shown in Figure 3, each restraint member 3 is arranged facing each other on both sides of the plate-like body 21 of the core member 2. Each restraint member 3 comprises a box-shaped member 31, a hardening member 32, and a metal reinforcing member 33. As shown in Figure 2, the metal reinforcing member 33 is embedded within the box-shaped member 31 by the hardening member 32, but in Figure 3, for convenience, the metal reinforcing member 33 is extracted from the box-shaped member 31 and shown by a two-dot chain line. Similar drawings will also be used in the explanation of other embodiments.

Each box-shaped member 31 is made of steel plate bent into a channel steel shape, having a pair of opposing surfaces and a connecting surface connecting the opposing surfaces, with an opening located on the core material 2 side. One side of the opposing surfaces of the box-shaped member 31 is higher than the other. The higher opposing surface of one box-shaped member 31 overlaps the outside of the lower opposing surface of the other box-shaped member 31, and this overlap is welded to secure the pair of restraint members 3 to each other. Furthermore, a rod-shaped spacer 35 extending longitudinally of the box-shaped member 31 is fixed by welding or other means to the inner surface of the higher opposing surface of each box-shaped member 31 at a position equivalent to the height at which the core material 2 is located. The presence of the rod-shaped spacer 35 restricts widthwise movement of the core material 2.

In addition, walls 31a that form the end shape of the box-shaped member 31 are welded to both ends of the box-shaped member 31. The height of the walls 31a is the same as the height of the opposing surface on the lower side of the box-shaped member 31. A recess 31b is formed in the center of the wall 31a by recessing it to avoid interference with the lowered portion of the plate portion 22b of the joint 22.

The hardening member 32 is filled into the box-shaped member 31 and hardened, and is, for example, mortar or concrete.

The metal reinforcing member 33 is embedded within the hardened member 32 and is integrated with the hardened member 32. The metal reinforcing member 33 also integrally comprises end reinforcing portions 33a located outside the recessed portions 31b at each end of the box-shaped member 31, and a central reinforcing portion 33b located at a non-end portion of the box-shaped member 31. The metal reinforcing member 33 is, for example, a welded wire mesh or a rebar grid. However, the metal reinforcing member 33 is not limited to a woven product such as a rebar grid; it may also be obtained by braiding steel rods or the like vertically and horizontally during the manufacturing process of the restraint member 3.

The width of each end reinforcement portion 33a is approximately the width between the edge of the box-shaped member 31 and the recessed portion 31b. The length of each end reinforcement portion 33a is longer than the length of the recessed portion 31b. The width of the center reinforcement portion 33b is approximately the same as the inner width of the box-shaped member 31. When using a long, rectangular welded wire mesh or the like that matches the shape of the restraint member 3, the metal reinforcement member 33 can be manufactured by cutting the center end of the welded wire mesh or the like to match the shape of the recessed portion 31b.

The core material 2 has pin-shaped anti-slip protrusions protruding from both sides at its center, while a metal receiving bracket is fixed to the inner surface of the box-shaped member 31 to receive the anti-slip protrusions. The mesh size of the welded wire mesh or other metal reinforcing material 33 is larger than that of the metal receiving bracket.

Next, we will briefly explain how to fabricate the restraint member 3 in the buckling restraint brace 1. As shown in Figure 4(A), the box-shaped member 31 is placed with its opening facing upward, and the metal reinforcement member 33 is set inside the box-shaped member 31. At this time, a mortar spacer (mortar die) or similar object having dimensions that determine the distance between the inner surface of the connecting surface of the box-shaped member 31 and the metal reinforcement member 33 is placed inside the box-shaped member 31, and the metal reinforcement member 33 is placed on top of this. Then, as shown in Figure 4(B), mortar or similar, which is the hardening member 32, is poured into the box-shaped member 31 and allowed to harden. The hardening member 32 is placed to a predetermined cover thickness on top of the metal reinforcement member 33.

With the above configuration, the metal reinforcing material 33 is disposed within the stiffening member 32, thereby increasing the strength of the buckling restraint brace 1. Furthermore, rather than surrounding the core material with metal reinforcing material, the core material 2 is sandwiched between the metal reinforcing material 33, making the structure simple and easy to manufacture.

In addition, in this embodiment, the metal reinforcement member 33 has end reinforcement portions 33a located at each end of the box-shaped member 31, and a central reinforcement portion 33b located at a non-end portion of the box-shaped member 31. This makes it possible to suppress cracking of the hardened members 32 located at each end of the box-shaped member 31 during transportation of the buckling restraint brace 1, compared to a configuration in which the metal reinforcement member 33 includes only the central reinforcement portion 33b.

Furthermore, in this embodiment, the end reinforcement portion 33a and the central reinforcement portion 33b are integral. Therefore, as described above, it is necessary to cut a portion of the central portion of the longitudinal end of the metal reinforcement member 33 and process it into a concave shape. However, since only one metal reinforcement member 33 is required for each box-shaped member 31, this has the advantage of simplifying the placement work on the box-shaped member 31.

Here, as shown in Figure 2, if the distance D0 between the surface of the hardened member 32 facing the core material 2 and the metal reinforcing member 33 is large, the bending rigidity of the restraining member 3 can be improved. On the other hand, if the distance D0 is small, the resistance of the restraining member 3 to local deformation during compression of the core material 2 can be improved and cracking of the hardened member 32 can be suppressed. Note that even when the distance D0 is small, the covering thickness of the hardened member 32 over the metal reinforcing member 33 is ensured.

Next, a modified example of embodiment 1 will be described with reference to Figures 5, 6(A), and 6(B). In the metal reinforcement 33 of the buckling restraint brace 1 according to this modified example, if the distance between the surface of the stiffening member 32 facing the core member 2 and the end reinforcement portion 33a is D1 and the distance between the surface of the stiffening member 32 facing the core member 2 and the center reinforcement portion 33b is D2, then D1 and D2 are different. In particular, in this modified example, D1 < D2, and the end reinforcement portion 33a is located close to the core member 2, while the center reinforcement portion 33b is located far away from the core member 2.

The arrangement region of the end reinforcement portion 33a, where the metal reinforcement member 33 is located near the core material 2, is advantageous in suppressing cracking of the hardened member 32. In other words, cracking of the hardened member 32 is likely to occur near the recessed portion 31b, and positioning the end reinforcement portion 33a close to the core material 2 helps to suppress such cracking. On the other hand, the arrangement region of the center reinforcement portion 33b, where the metal reinforcement member 33 is located farther from the core material 2, improves the bending rigidity of the restraint member 3.

In this modified example of Embodiment 1, the metal reinforcing member 33 is bent into a generally trapezoidal shape, but this is not limiting, and the metal reinforcing member 33 may also be bent into a generally triangular (mountain) shape.

(Embodiment 2)
Another embodiment of the present invention will be described below with reference to Figure 7. Components similar to those in the first embodiment are designated by the same reference numerals, and their description will be omitted. The metal reinforcement member 33 in the buckling restrained brace 1 of this embodiment has end reinforcement portions 33a and a center reinforcement portion 33b, which are separate bodies.

The length of the central reinforcement portion 33b is such that it does not overlap the recessed portion 31b within the non-end portion of the box-shaped member 31. The length of the end reinforcement portion 33a is slightly longer than the depth of the recessed portion 31b from the end of the wall portion 31a. In other words, the end reinforcement portion 33a extends toward the central reinforcement portion 33b, and the two overlap in approximately the same plane.

In the buckling restraint brace 1 of this embodiment 2, the metal reinforcement member 33 is composed of four small, standard rectangular end reinforcement sections 33a and one large, rectangular central reinforcement section 33b, which has the advantage of eliminating the need for cutting as shown in embodiment 1.

Next, a modified version of Embodiment 2 will be described with reference to Figure 8. In this modified version of the buckling restraint brace 1, the metal reinforcement member 33 has end reinforcement portions 33a and central reinforcement portions 33b positioned at different heights, and the end reinforcement portions 33a and central reinforcement portions 33b partially overlap in three dimensions. That is, as shown in Figure 6, if the distance between the surface of the hardening member 32 facing the core material 2 and the end reinforcement portion 33a is D1 and the distance between the surface of the hardening member 32 facing the core material 2 and the central reinforcement portion 33b is D2, then D1 and D2 are different. In particular, in this modified version, D1 < D2, and the end reinforcement portions 33a are positioned near the core material 2, while the central reinforcement portion 33b is positioned farther from the core material 2.

In addition, in this modified buckling restraint brace 1, the end reinforcement portion 33a and the center reinforcement portion 33b are arranged in a three-dimensional intersection to form an open lap joint, so it is preferable that the metal reinforcement member 33 be made of deformed steel bars rather than round steel bars.

(Embodiment 3)
Another embodiment of the present invention will be described below with reference to Fig. 9. Note that the same components as those in the first embodiment are designated by the same reference numerals and their description will be omitted.

In the buckling restrained brace 1 of this embodiment, two strip-shaped metal reinforcing members 33A are arranged adjacent to each other, with end reinforcing members 33a and central reinforcing members 33b integrated with the same width (approximately the width between the edge of the box-shaped member 31 and the recessed portion 31b). A gap roughly the same width as the recessed portion 31b is created between the two metal reinforcing members 33A. However, compared to a structure in which no metal reinforcing member is arranged at all, this contributes to suppressing cracking of the hardened member 32 and improving the bending rigidity of the restraining member 3. Furthermore, with the buckling restrained brace 1 of this embodiment, there is no need to process the metal reinforcing members into a concave shape; instead, the task is to arrange two strip-shaped metal reinforcing members 33 of the same type within the box-shaped member 31, making it easier to manufacture the restraining member 3.

In the buckling restraint brace 1 of this embodiment 3, as in the modified example of embodiment 1, in each metal reinforcement 33A, the end reinforcement 33a may be bent relative to the center reinforcement 33b so that the distance between the surface of the hardening member 32 facing the core material 2 and the end reinforcement 33a is different from the distance between the surface of the hardening member 32 facing the core material 2 and the center reinforcement 33b.

Next, a modified version of embodiment 3 will be described with reference to Figure 10. In this modified buckling restraint brace 1, another metal reinforcing member 33B of approximately the same length as the central reinforcing portion 33b is provided at a non-end portion of the box-shaped member 31, spanning the two metal reinforcing members 33A in approximately the same plane as the plane in which the metal reinforcing members 33A are arranged. As a result, the two metal reinforcing members 33A are joined by the other metal reinforcing member 33B, thereby improving reinforcing strength.

In this modified buckling restraint brace 1, if the distance between the surface of the hardening member 32 facing the core material 2 and the metal reinforcement member 33A is D3, and the distance between the surface of the hardening member 32 facing the core material 2 and the other metal reinforcement member 33B is D4, D3 and D4 may be different. For example, D3 < D4 may be set, with the metal reinforcement member 33A positioned close to the core material 2 and the other metal reinforcement member 33B positioned farther away from the core material 2.

(Embodiment 4)
Another embodiment of the present invention will now be described with reference to FIG. 11 . The overall configuration of the buckling-restrained brace 1 of this embodiment is similar to that of the buckling-restrained brace 1 of the first embodiment and other embodiments. The difference is that the central reinforcing portions 33 b of the metal reinforcing members 33 ( 33A ) have a wave shape with a constant wavelength that repeatedly approaches and moves away from the core material 2 in the longitudinal direction of the core material 2. Specifically, the peaks of the wave shape of each central reinforcing portion 33 b on the core material 2 side face the predicted peak position of the core material 2 when the core material 2 is deformed into a wave shape under compressive force. The constant-wavelength wave shape of the central reinforcing portions 33 b improves the strength (local strength) of the stiffening member 32 relative to the predicted peak position of the core material 2 and improves the bending rigidity of the core material 2 at locations other than the predicted peak position.

The predicted apex position (wavelength) when the core material 2 is compressed can be obtained by calculation based on the design values of the core material 2, such as its thickness.

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 restraint brace 2: Core material 3: Restraint material 21: Plate-like body 22: Joint portion 22a: Extension portion 22b: Plate piece portion 31: Box-shaped member 31a: Wall portion 31b: Recessed portion 32: Hardened member 33: Metal reinforcing member 33A: Metal reinforcing member 33B: Metal reinforcing member 33a: End side reinforcing portion 33b: Center side reinforcing portion 35: Rod-shaped spacer

Claims (7)

A buckling restrained brace having a core member having joints at both ends of a long, narrow plate-like body in the longitudinal direction, and a pair of restraint members arranged opposite each face of the core member,
The restraining material is:
a box-shaped member having an opening formed on the side where the core material is located and recessed portions formed at the center of both end portions overlapping with the joint portion so as to avoid interference with the joint portion;
a hardened member filled in the box-shaped member and hardened;
A buckling restraint brace comprising: end reinforcement portions located outside the recesses at each end of the box-shaped member; and a central reinforcement portion located at a non-end portion of the box-shaped member; and a metal reinforcement material disposed within the stiffening member. 2. The buckling restrained brace according to claim 1 , wherein the end reinforcement portions and the center reinforcement portion are integral with each other. 2. The buckling restraint brace according to claim 1 , wherein the end reinforcement portion and the central reinforcement portion are separate bodies, and the end reinforcement portion extends toward the central reinforcement portion, overlapping each other. 2. The buckling restraint brace according to claim 1 , characterized in that two strip-shaped metal reinforcing members, each having the end reinforcing portion and the central reinforcing portion of the same width, are arranged adjacent to each other. 5. The buckling restraint brace according to claim 4 , wherein another metal reinforcing member is provided across the two strip-shaped metal reinforcing members at a non-end portion of the box-shaped member. A buckling restraint brace as described in any one of claims 1 to 5 , characterized in that, when the distance between the surface of the hardened member facing the core material and the end reinforcement portion is D1 and the distance between the surface of the hardened member facing the core material and the center reinforcement portion is D2, D1 < D2. A buckling restraint brace as described in any one of claims 1 to 5 , characterized in that the central reinforcement portion has a wave shape that repeatedly approaches and moves away from the core material in the longitudinal direction of the core material, and the peak point of the wave-like amplitude of the central reinforcement portion faces the predicted peak position of the amplitude of the wave-like deformation due to compression of the core material.