US20130139452A1

US20130139452A1 - Buckling restrained brace

Info

Publication number: US20130139452A1
Application number: US13/751,773
Authority: US
Inventors: Keh-Chyuan Tsai; An-Chien WU; Chih-Yu WEI; Pao-Chun Lin
Original assignee: National Applied Research Laboratories
Current assignee: National Applied Research Laboratories
Priority date: 2011-03-18
Filing date: 2013-01-28
Publication date: 2013-06-06

Abstract

A buckling restrained brace includes an axial member, a plurality of restraining members, and a plurality of securing units. The axial member includes a middle section extending in an axial direction, and two coupling sections extending respectively from opposite ends of the middle section and coupled fixedly to two connecting plates of a framework of a building. The restraining members extend in the axial direction and are disposed around and contact the axial member. Each securing unit secures an adjacent pair of the restraining members together. Each restraining member cooperates with an adjacent one of the restraining members to define an opening therebetween through which a portion of the axial member is exposed for viewing.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part (CIP) of co-pending U.S. patent application Ser. No. 13/106,397, filed on May 12, 2011, and abandoned as of the filing date of this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to a buckling restrained brace, more particularly to a buckling restrained brace that includes an axial member visible from the outside of a wall structure in which the buckling restrained brace is embedded.
2. Description of the Related Art
Concentrically braced frames are generally used in a framework of a building for enhancing economically the lateral stiffness of the framework to resist lateral force of an earthquake. A buckling restrained brace, which is a kind of the concentrically braced frames, is particularly configured to have a relatively full hysteresis loop for effectively absorbing vibration energy generated by the earthquake so as to minimize damage to the framework resulting from the shock of the earthquake. A conventional buckling restrained brace generally includes an axial member that is surrounded fixedly by a restraining member, and that is not visible from the outside of the restraining member. As a result, the restraining member has to be destroyed before an examination as to whether the axial member needs to be changed may be made. However, once the restraining member is destroyed, the entire buckling restrained brace would be damaged and has to be replaced by a new one, regardless of whether the axial member was damaged by the shock of the earthquake.
As shown in FIGS. 1 and 2, Taiwanese Patent No. 0219077 discloses another conventional buckling restrained brace 9 that comprises an elongated axial member 91 having a cross-shaped cross section, and four restraining members 92 disposed around and contacting the axial member 91. The conventional buckling restrained brace 9 further comprises a pair of U-shaped steel clamping members 97, four angled steel components 90, and a pair of intermediate blocks 99. The clamping members 97 are disposed in a manner that each of the clamping members 97 contains two of the restraining members 92 therein, and that opposite ends of one of the clamping members 97 are adjacent to opposite ends of the other one of the clamping members 97, respectively. The angled steel components 90 are connected respectively to opposite ends of the clamping members 97. Each of the intermediate blocks 99 is fitted between an adjacent pair of the angled steel components 90. Each adjacent pair of the angled steel components 90 are secured together by a securing unit 98, which includes a bolt that extends through the adjacent pair of the angled steel components 90 and a nut that is secured to the bolt. As such, the clamping members 97 can be removed reattachably from the restraining members 92 before conducting damage examination of the axial member 91. However, since the conventional buckling restrained brace 9 is embedded in a wall structure, a part of the wall structure has to be broken before the clamping members 97 can be removed. Accordingly, the damage examination procedure of the conventional buckling restrained brace 9 is still relatively troublesome.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a buckling restrained brace which can be easily examined after being subjected to shock of an earthquake.
Accordingly, a buckling restrained brace of the present invention is adapted to be connected fixedly between two connecting plates of a framework of a building. The buckling restrained brace comprises an axial member, a plurality of restraining members, and a plurality of securing units. The axial member includes a middle section that extends in an axial direction and that has opposite ends in the axial direction, and a pair of coupling sections that extend respectively from the opposite ends of the middle section and that are adapted to be coupled fixedly to the connecting plates, respectively. The restraining members extend in the axial direction, and are disposed around and contact the axial member. Each of the securing units secures an adjacent pair of the restraining members together. Each of the restraining members cooperates with an adjacent one of the restraining members to define an opening therebetween through which a portion of the axial member is exposed for viewing.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:

FIG. 1 is a schematic side view of a conventional buckling restrained brace disclosed in Taiwanese Patent No. 0219077;

FIG. 2 is a sectional view of the conventional buckling restrained brace disclosed in Taiwanese Patent No. 0219077;

FIG. 3 is a schematic view of a first preferred embodiment of a buckling restrained brace according to the invention which is connected to a steel framework;

FIG. 4 is a fragmentary partly cutaway perspective view of the first preferred embodiment, illustrating a plurality of restraining members disposed around an axial member and secured together by a plurality of securing units;

FIG. 5 is another fragmentary partly cutaway perspective view of the first preferred embodiment, illustrating a plurality of modified restraining members disposed around a modified axial member and secured together by a plurality of modified securing units;

FIG. 6 is a fragmentary partly cutaway perspective view of a wall structure mounted with the first preferred embodiment;

FIG. 7 is a sectional view of the first preferred embodiment having another form of modified restraining members;

FIG. 8 is another sectional view of the first preferred embodiment having yet another form of modified restraining members;

FIG. 9 is another fragmentary partly cutaway perspective view of the first preferred embodiment, illustrating modified securing units;

FIG. 10 is a sectional view of a second preferred embodiment of the buckling restrained brace according to the invention, illustrating the restraining members mounted respectively with enhancing components;

FIG. 11 is another sectional view of the second preferred embodiment, illustrating the restraining members mounted respectively with modified enhancing components;

FIG. 12 is still another sectional view of the second preferred embodiment having another form of modified restraining members;

FIG. 13 is a fragmentary partly cutaway perspective view of the second preferred embodiment having yet another form of modified restraining members;

FIG. 14 is a sectional view of a third preferred embodiment of the buckling restrained brace according to the invention;

FIG. 15 is a fragmentary partly cutaway perspective view of the third preferred embodiment, illustrating modified securing units; and

FIG. 16 is a sectional view of a fourth preferred embodiment of the buckling restrained brace according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted that like elements are denoted by the same reference numerals throughout the disclosure.
As shown in FIGS. 3 to 6, the first preferred embodiment of a buckling restrained brace according to the present invention is adapted to be connected fixedly between two connecting plates 6 of a framework 5 of a structure. The structure is, for example, a building, a bridge, a wharf, a dam, a tower, an electrical tower or a tunnel. The structure includes a structure body connected to the framework 5. In this embodiment, the structure is a building, and the structure body has a wall structure that includes a pair of spaced-apart wall plates 9 (only one is shown in FIG. 6). One of the wall plates 9 is formed with a through hole 92. The framework 5 and the buckling restrained brace of this invention are disposed between the wall plates 9. The buckling restrained brace comprises an axial member 1, a restraining unit 2, and a plurality of securing units 30.
The axial member 1 is configured as an elongated steel plate, and includes a middle section 11 extending in an axial direction (L) and having opposite ends in the axial direction (L), and a pair of coupling sections 12 extending respectively from the opposite ends of the middle section 11 and adapted to be coupled fixedly and respectively to the connecting plates 6 through a variety of joints, such as butt joints, lap joints, and so on.
The restraining unit 2 includes a plurality of restraining members 21 extending in the axial direction (L) and disposed around and contacting the axial member 1. In this embodiment, the restraining unit 2 includes a pair of restraining members 21 clamping the axial member 1 therebetween. Each of the restraining members is configured as a steel rectangular tube. The restraining members 21 cooperate with each other to define two openings 20 therebetween. One of the openings 20 is registered with the through hole 92 in the one of the wall plates 9, such that a portion of the axial member 1 is exposed for viewing from the outside of one of the wall plates 9 through the through hole 92.
Each of the restraining members 21 has a surface 2101 that contacts a surface 101 of the axial member 1, and that has a contour substantially the same as that of the surface 101 of the axial member 1. Preferably, a ratio of a width of the surface 2101 of each of the restraining members 21 to that of the surface 101 of the axial member 1 ranges from 0.1 to 2.0. FIGS. 4 and 5 illustrate two variations of the axial member 1 and the corresponding restraining members 21. As such, the axial member 1 can be clearly viewed through the one of the openings 20 which is registered with the through hole 92 for examination, and obstruction to the viewing of the axial member 1 due to overly large size of the restraining members 21 may be prevented.
As shown in FIG. 7, each restraining member 21 may be modified to be solid with a T-shaped cross-section. Each restraining member 21 has a base wall 211 abutting against the middle section 11 of the axial member 1 and an extending wall 212 extending from a central portion of the base wall 211 in a direction away from the axial member 1. Referring to FIG. 8, each restraining member 21 may also be modified to be U-shaped and to have a base wall 211′ abutting against the middle section 11 of the axial member 1 and two extending walls 212′ extending respectively from opposite lateral ends of the base wall 211′ in the direction away from the axial member 1.
Each of the securing units 30 includes a pair of spaced-apart connecting components 3 and a plurality of fastening units 4. The connecting components 3 extend in the axial direction (L), are located adjacent to a respective one of the openings 20, and are connected respectively to the restraining members 21. In this embodiment, the fastening units 4 of each securing unit 30 are spaced-apart from each other in the axial direction (L), and each of which is configured as a solder 41 fitted between the connecting components 3 of a corresponding one of the securing units 30 for securing the connecting components 3 together. Preferably, each of the securing units 30 further includes a plurality of spaced-apart reinforcing members 43 that are spaced apart from the fastening units 4 in the axial direction (L) and fitted between the connecting components 3 of the corresponding one of the securing units 30. As shown in FIG. 9, each of the fastening units 4 may be modified to include a bolt 42 extending through the corresponding one of the securing units 30 for securing the connecting components 3, and a nut 45 secured threadedly to the bolt 42. Preferably, each of the fastening units 4 further includes a plurality of intermediate blocks 44, each of which is provided between the connecting components 3 of the corresponding one of the securing units 30 for extension of the bolt 42.
Since the axial member 1 is visible through the through hole 92, it can be directly examined after suffering from shock of an earthquake without requiring removal of the restraining unit 2 from the axial member 1.
As shown in FIGS. 10 and 11, the second preferred embodiment of the buckling restrained brace according to the present invention has a structure similar to that of the first embodiment. The main difference between this embodiment and the previous embodiment resides in the following. In this embodiment, the restraining unit 2 further includes a plurality of enhancing components 24 connected to the restraining members 21 for enhancing structural strength to resist buckling of the buckling restrained brace in the cross-sectional direction. Each enhancing component 24 may be configured to be concrete (see FIG. 10) filled within the corresponding one of the restraining members 21, or be configured as a pair of spaced-apart steel plates (see FIG. 11), each having opposite lateral edges abutting against an inner surface of the hollow restraining member 21.
In addition, referring to FIG. 12, each of the securing units 30 may be configured to have only the fastening unit 4, in which the bolt 42 extends directly through the retaining members 21, and the nut 45 is secured threadedly to the bolt 42. Moreover, as shown in FIG. 13, the restraining members 21 may be configured to surround cooperatively the axial member 1 therebetween, i.e., each of the two restraining members 21 contains a half of the axial member 1 therein, and the restraining members 21 are directly connected to each other at lateral sides of the axial member 1. A notch 217 is formed at the connected portions of the restraining members 21 to be registered with one of the openings 20. The second preferred embodiment has the same advantages as those of the first preferred embodiment.
As shown in FIG. 14, the third preferred embodiment of the buckling restrained brace according to the present invention has a structure similar to that of the first preferred embodiment. The main difference between this embodiment and the first preferred embodiment resides in the following. In this embodiment, the axial member 1 is formed to have a cross-shaped cross section, and the restraining unit 2 includes four restraining members 21 disposed around and abutting against the axial member 1. The connecting components 3 of each of the securing units 30 are located adjacent to the opening 20 between an adjacent pair of the restraining members 21, and are connected respectively to the adjacent pair of the restraining members 21. Each of the connecting components 3 may be configured as an angled steel component, or a sheet steel component (see FIG. 15) soldered to the adjacent pair of the restraining members 21 by virtue of the solders 41. The third preferred embodiment has the same advantages as those of the first preferred embodiment.
As shown in FIG. 16, the fourth preferred embodiment of the buckling restrained brace according to the present invention has a structure similar to that of the third preferred embodiment. The main difference between this embodiment and the third preferred embodiment resides in the following. In this embodiment, the buckling restrained brace comprises a pair of axial members 1 and three restraining members 21 that are alternately disposed (i.e., each axial member 1 is clamped between an adjacent pair of the restraining members 21).
While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.

Claims

What is claimed is:

1. A buckling restrained brace adapted to be connected fixedly between two connecting plates of a framework of a building, said buckling restrained brace comprising:

an axial member including a middle section that extends in an axial direction and that has opposite ends in the axial direction, and a pair of coupling sections that extend respectively from said opposite ends of said middle section and that are adapted to be coupled fixedly to the connecting plates, respectively;

a plurality of restraining members that extend in the axial direction, and that are disposed around and contacting said axial member, each of said restraining members having a surface that contacts a surface of said axial member and that has a contour substantially the same as that of said surface of said axial member; and

a plurality of securing units, each of which secures an adjacent pair of said restraining members together;

wherein each of said restraining members cooperates with an adjacent one of said restraining members to define an opening therebetween through which a portion of said axial member is exposed for viewing.

2. The buckling restrained brace as claimed in claim 1, wherein a ratio of a width of said surface of each of said restraining members to that of said surface of said axial member ranges from 0.1 to 2.0.

3. The buckling restrained brace as claimed in claim 1, wherein each of said securing units includes:

a pair of connecting components extending in the axial direction, located adjacent to said opening of the adjacent pair of said restraining members, and connected respectively to the adjacent pair of said restraining members; and

a plurality of fastening units spaced apart from each other in the axial direction and fastening said connecting components together.

4. The buckling restrained brace as claimed in claim 3, wherein each of said fastening units of each of said securing units is configured as a solder fitted between a corresponding pair of said connecting components.

5. The buckling restrained brace as claimed in claim 3, wherein each of said fastening units of each of said securing units includes a bolt extending through a corresponding pair of said connecting components, and a nut secured threadedly to said bolt.

6. The buckling restrained brace as claimed in claim 3, wherein each of said securing units further includes a plurality of spaced-apart reinforcing members spaced apart from said fastening units in the axial direction and fitted between a corresponding pair of said connecting components.

7. The buckling restrained brace as claimed in claim 1, wherein each of said securing units includes a bolt extending through the adjacent pair of said restraining members, and a nut secured threadedly to said bolt.

8. A building comprising:

a wall structure including a pair of spaced-apart wall plates, one of said wall plates being formed with a through hole; and

a framework disposed between said wall plates, and including a pair of connecting plates and a buckling restrained brace that is connected fixedly between said connecting plates, and that includes

an axial member including a middle section that extends in an axial direction and that has opposite ends in the axial direction, and a pair of coupling sections that extend respectively from said opposite ends of said middle section and that are coupled fixedly to the connecting plates, respectively,

a plurality of restraining members extending in the axial direction, and disposed around and contacting said axial member, and

a plurality of securing units, each of which secures an adjacent pair of said restraining members together,

wherein each of said restraining members cooperates with an adjacent one of said restraining members to define an opening therebetween, one of said openings being registered with said through hole of said one of said wall plates so that a portion of said axial member is exposed for viewing.

9. A structure comprising:

a structure body; and

a framework disposed in said structure body and including a pair of connecting plates and a buckling restrained brace that is connected fixedly between said connecting plates, and that includes

an axial member including a middle section that extends in an axial direction and that has opposite ends in the axial direction, and a pair of coupling sections that extend respectively from said opposite ends of said middle section and that are coupled fixedly and to said connecting plates, respectively,

10. The structure as claimed in claim 9, wherein each of said restraining members of said framework has a surface that contacts a portion of said axial member of said framework and that has a contour substantially the same as that of said surface of said axial member.

11. The structure as claimed in claim 10, wherein a ratio of a width of said surface of each of said restraining members to that of said surface of said axial member ranges from 0.1 to 2.0.

12. The structure as claimed in claim 9, wherein said structure body includes a pair of spaced-apart wall plates, one of said wall plates being formed with a through hole, one of said openings being registered with said through hole.

13. The structure as claimed in claim 9, wherein said structure is one of a building, a bridge, a wharf, a dam, a tower, an electrical tower and a tunnel.