US20170081845A1

US20170081845A1 - Brace member

Info

Publication number: US20170081845A1
Application number: US15/310,631
Authority: US
Inventors: Tomohiro Kinoshita; Takumi Ishii; Kazuaki Miyagawa; Mitsutoshi Yoshinaga; Wataru Kitamura
Original assignee: JFE Steel Corp; JFE Civil Engineering and Construction Corp
Current assignee: JFE Steel Corp; JFE Civil Engineering and Construction Corp
Priority date: 2014-05-19
Filing date: 2015-05-13
Publication date: 2017-03-23
Also published as: CN106414871A; JP2015218498A; JP6204263B2; WO2015177987A1; KR20190026982A; TW201600691A; KR102025055B1; TWI615535B; KR20170007282A

Abstract

A brace member includes a plastically deformable core member, a buckling restraining member through which the core member extends, a cap sleeve in which a first end portion of the core member and a first end portion of the buckling restraining member are disposed, a cap-sleeve crevice disposed on the cap sleeve so as to protrude toward a side opposite to a side on which the core member and the buckling restraining member are disposed, a reinforcing member in which a second end portion of the core member is disposed, and a reinforcing-member crevice disposed on the reinforcing member so as to protrude toward a side opposite to a side on which the core member is disposed. The reinforcing member surrounds a predetermined area of the buckling restraining member extending from a second end surface on the second side in the longitudinal direction.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase application of PCT/JP2015/002421, filed May 13, 2015, and claims priority to Japanese Patent Application No. 2014-103271, May 19, 2014, the disclosures of each of these applications being incorporated herein by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present invention relates to brace members, and particularly to a brace member that includes a core member, which absorbs the seismic energy in occurrences of earthquakes, and a buckling restraining member, which stiffens the core member.

BACKGROUND OF THE INVENTION

Existing brace members installed in architectural structures to deal with occurrences of earthquakes include a core member, which absorbs seismic energy, and a stiffening member, which restricts out-of-plane (direction perpendicular to longitudinal direction) deformation that occurs when compressive force acts in the longitudinal direction of the core member. The brace members prevent or retard an occurrence of buckling of the entirety of the core member even when the compressive axial force acts to cause stable deformation in the axial direction and enhance the ability to absorb seismic energy.
The applicant of patent has disclosed a brace member (for example, see Patent Literature 1) that is easily manufacturable and that can prevent a weight increase as a result of eliminating a welding operation for disposing a core member and a stiffening member in a predetermined form and an operation of filling a space between the core member and the stiffening member with mortar.

CITATION LIST

Patent Literature

[PTL 1] Japanese Unexamined Patent Application Publication No. 2013-112949 (pages 4 to 5 and FIG. 1)

SUMMARY OF THE INVENTION

In the brace member disclosed in Patent Literature 1, crevices are connected, with screw threads, to both end portions of the core member that extends through the buckling restraining member and that is made of a steel bar. A first end portion of the buckling restraining member is secured with screw threads to a first end portion of the core member with a retaining ring interposed therebetween, the retaining ring being screwed on the buckling restraining member and the core member. On the other hand, a sleeve made of a steel pipe is secured, with a screw thread, to a second end portion of the core member. Substantially half the sleeve in the longitudinal direction is inserted into the buckling restraining member and the remaining substantially half the sleeve is exposed beyond the buckling restraining member. Here, a gap having a predetermined size is formed between the external circumference of the sleeve and the internal circumference of the buckling restraining member. Such a brace member thus has a remarkable effect that allows the core member to be disposed at a predetermined position relative to the buckling restraining member without performing a welding operation and a remarkable effect that allows elimination of an operation of filling a space between the core member and the stiffening member with mortar.
However, the thickness of the sleeve is required to be smaller than half the difference between the inner diameter of the stiffening member and the outer diameter of the core member. On the other hand, the inner surface of the stiffening member is preferably located near the outer surface of the core member to deliver its stiffening performance.
Thus, the thickness of the sleeve naturally has its limit. If the sleeve has a small bending strength due to this limit, the sleeve may be yielded due to bending in a range of the sleeve exposed beyond the buckling restraining member. In this case, the core member may be buckled within this range since no buckling restraining member is originally disposed between the second end surface of the buckling restraining member and the end portion of the crevice secured with a screw to the second end portion of the core member and the sleeve has been yielded.
To address this, a brace member having bending strength enhanced (increased) by a mechanism substitute for the sleeve has been demanded.
Aspects of the present invention were made to respond to the above-described demand and aims to provide a brace member having high (great) bending strength.
(1) A brace member according to aspects of the present invention includes a core member, a buckling restraining member through which the core member extends and that restricts out-of-plane deformation of the core member, a cap sleeve in which a first end portion of the core member on a first side in a longitudinal direction and a first end portion of the buckling restraining member on the first side in the longitudinal direction are disposed, a cap-sleeve crevice disposed on the cap sleeve so as to protrude toward a side opposite to a side on which the core member and the buckling restraining member are disposed, the cap-sleeve crevice serving as a joint for installing the brace member on an architectural structure, a reinforcing member in which a second end portion of the core member on a second side in the longitudinal direction is disposed, and a reinforcing-member crevice disposed on the reinforcing member so as to protrude toward a side opposite to a side on which the core member is disposed, the reinforcing-member crevice serving as a joint for installing the brace member on the architectural structure. The reinforcing member surrounds a predetermined area of the buckling restraining member extending from a second end surface on the second side in the longitudinal direction.
(2) A brace member according to aspects of the present invention includes a core member, a buckling restraining member through which the core member extends and that restricts out-of-plane deformation of the core member, reinforcing members disposed individually on two ends of the core member in a longitudinal direction, and reinforcing-member crevices disposed individually on the reinforcing members so as to each protrude toward a side opposite to a side on which the core member is disposed, the reinforcing-member crevices serving as joints for installing the brace member on an architectural structure. Each of the reinforcing members surrounds a predetermined area of the buckling restraining member extending from a corresponding one of end portions of the buckling restraining member in the longitudinal direction.
(3) Further, in the above-described paragraph (1) or (2), an inner diameter of the reinforcing member(s) in the range in which the reinforcing member(s) surrounds the buckling restraining member is constant in the longitudinal direction, and an outer diameter of the reinforcing member(s) in the range decreases toward a center of the buckling restraining member in the longitudinal direction.
(i) In the brace member according to aspects of the present invention, the first end portion of the buckling restraining member on the first side in the longitudinal direction is disposed in the cap sleeve and a predetermined area of the buckling restraining member extending from the second end surface on the second side in the longitudinal direction is surrounded by the reinforcing member. In other words, the reinforcing member surrounds the external circumferential surface of the buckling restraining member and the thickness of the reinforcing member is not limited. Thus, compared with an existing sleeve (disposed between the core member and the buckling restraining member), the outer diameter (and the inner diameter) and the thickness can be increased, whereby the stiffness can be enhanced.
Here, deformation of the predetermined area of the buckling restraining member extending from the second end surface on the second side in the longitudinal direction is restricted by the reinforcing member having high stiffness and the core member is prevented from being buckled. Thus, the brace member according to aspects of the present invention is a brace member having high (great) bending strength.
(ii) When predetermined areas of the buckling restraining member extending from both end portions of the buckling restraining member in the longitudinal direction are surrounded by respective reinforcing members, the above-described effect is obtained. Moreover, the elimination of the need for the cap sleeve enables reduction of the number of types of components, whereby manufacturing costs or inventory costs can be kept low.
(iii) In addition, since the outer diameter of the reinforcing member decreases toward the tip end (toward the center of the buckling restraining member in the longitudinal direction), the weight reduction can be enhanced and the design can be improved while the strength at each position in the longitudinal direction is secured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a brace member according to a first embodiment of the present invention. FIG. 1(a) is a side view of the brace member and FIG. 1(b) is a sectional view of a main portion of the brace member viewed sideways.

FIG. 2 illustrates a specimen that undergoes a loading test to evaluate the performances of the brace member according to the first embodiment of the present invention and is a sectional view viewed sideways to define the length of each component.

FIG. 3 illustrates a specimen that undergoes a loading test to evaluate the performances of an existing brace member for use as a comparative example and is a sectional view viewed sideways to define the length of each component.

FIG. 4 has axial force-axial strain chart(s) showing the results of the loading test conducted to clarify the performances of the brace member according to the first embodiment of the present invention. FIG. 4(a) is a chart for a specimen No. 1 and FIG. 4(b) is a chart for a specimen No. 2.

FIG. 5 is an axial force-axial strain chart showing the results of the loading test conducted to clarify the performances of an existing brace member of a comparative example.

FIG. 6 illustrates a brace member according to a second embodiment of the present invention. FIG. 6(a) is a side view of the brace member and FIG. 6(b) is a sectional view of a main portion of the brace member viewed sideways.

FIG. 7 illustrates a brace member according to a third embodiment of the present invention. FIG. 7(a) is a side view of the brace member and FIG. 7(b) is a sectional view of a main portion of the brace member viewed sideways.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

First Embodiment

FIG. 1 illustrates a brace member according to a first embodiment of the present invention. FIG. 1(a) is a side view of the brace member and FIG. 1(b) is a sectional view of a main portion of the brace member viewed sideways. Each of the diagrams is schematically drawn and the dimensions such as the relative size or thickness of each component are not limited to those illustrated in the drawings. In FIG. 1, the left side is referred to as “a first side in the longitudinal direction” and the right side is referred to as “a second side in the longitudinal direction”.
In FIG. 1, a brace member 100 includes a core member 10, a buckling restraining member 20 through which the core member 10 extends and that surrounds the core member 10 to restrict out-of-plane deformation of the core member 10, a cap sleeve 30 in which a first end portion 11 a of the core member 10 on the first side in the longitudinal direction and a first end portion 21 a of the buckling restraining member 20 on the first side in the longitudinal direction are disposed, a cap-sleeve crevice 40 disposed on the cap sleeve 30 so as to protrude toward a side opposite to a side on which the core member 10 and the buckling restraining member 20 are disposed, the cap-sleeve crevice 40 serving as a joint for installing the brace member 100 on an architectural structure (not illustrated), a reinforcing member 50 in which a second end portion 11 b of the core member 10 on the second side in the longitudinal direction is disposed, and a reinforcing-member crevice 60 disposed on the reinforcing member 50 so as to protrude toward a side opposite to a side on which the core member 10 is disposed, the reinforcing-member crevice 60 serving as a joint for installing the brace member 100 on an architectural structure (not illustrated).

(Core Member)

The core member 10 is a long member formed from a steel bar having a circular cross section. A male screw thread 12 a is formed at the first end portion 11 a on the first side in the longitudinal direction and a male screw thread 12 b is formed at the second end portion 11 b on the second side in the longitudinal direction. For convenience of illustration, the core member 10 made of a steel bar having a circular cross section is illustrated. However, the core member 10 is not limited to the one having this cross section and may be formed from, for example, a steel pipe or may be formed by joining flat boards so as to have a cross-shaped cross section.
When the core member 10 is made of a plastically deformable material, the core member 10 has a higher effect. In order to prevent noises and an excessive increase in axial force due to friction that occur when the external circumferential surface of the core member 10 and the internal circumferential surface of the buckling restraining member 20 slide over each other, a liner made of a material such as a synthetic resin may be disposed on the external circumferential surface of the core member 10.

(Buckling Restraining Member)

The buckling restraining member 20 is a steel pipe having a circular cross section and shorter than the core member 10. A male screw thread 22 a is formed at the first end portion 21 a on the first side in the longitudinal direction (a male screw thread or the like is not formed at a second end portion 21 b on the second side in the longitudinal direction).
Here, the buckling restraining member 20 may have a rectangular cross section.

(Cap Sleeve)

The cap sleeve 30 includes a cylindrical portion 33 low in height. A female screw thread 34 is formed in a first end surface 30 a, a female screw thread 32 is formed in a second end surface 30 b, and a female screw thread 31 is formed through the center of the cylindrical portion 33. The female screw thread 34, the female screw thread 32, and the female screw thread 31 are concentric with one another.
The male screw thread 12 a of the core member 10 is screwed on the female screw thread 31. The male screw thread 22 a of the buckling restraining member 20 is screwed on the female screw thread 32. A male screw thread 43 (described below) of the cap-sleeve crevice 40 is screwed on the female screw thread 34.
A tapered portion 30 c, whose outer diameter decreases toward the second end surface 30 b, is formed in a range of the external circumferential surface near the second end surface 30 b. However, instead of forming the tapered portion 30 c, the corner portion may be chamfered as in the case of the first end surface 30 a.

(Cap-Sleeve Crevice)

The cap-sleeve crevice 40 serves as a joint for installing the brace member 100 in an architectural structure (not illustrated). The cap-sleeve crevice 40 includes a disk-shaped portion 41, a plate-shaped portion 42 disposed on the first end surface of the disk-shaped portion 41, an attachment hole 44 that extends through the plate-shaped portion 42, and a male screw thread 43 disposed on the external circumferential surface of the disk-shaped portion 41. Here, the central axis of the attachment hole 44 and the central axis of the disk-shaped portion 41 perpendicularly cross each other (not geometrically accurately but industrially accurately cross each other).
In the above-described configuration, the cap sleeve 30 and the cap-sleeve crevice 40 are separately manufactured and are integrated together with screw connection. However, the present invention is not limited to this configuration. The cap sleeve 30 and the cap-sleeve crevice 40 may be integrated together by mechanical joining such as shrinkage fit or metallurgic joining such as welding. Alternatively, the cap sleeve 30 and the cap-sleeve crevice 40 may be originally manufactured as an integrated unit by, for example, casting.

(Reinforcing Member)

The reinforcing member 50 includes a tubular portion 52 and a disk-shaped portion 55. A female screw thread 56 is formed in a second end surface 50 b of the disk-shaped portion 55 and a female screw thread 51 is formed through the center of the disk-shaped portion 55.
The male screw thread 12 b of the core member 10 is screwed on the female screw thread 51 and a male screw thread 65 (described below) of the reinforcing-member crevice 60 is screwed on the female screw thread 56.
The inner diameter of the tubular portion 52 is constant in the longitudinal direction. The central axis of the tubular portion 52, the central axis of the female screw thread 51, and the central axis of the female screw thread 56 coincide with one another. The tubular portion 52 surrounds the second end portion 21 b (an area extending a predetermined distance from an end surface 20 b) of the buckling restraining member 20 on the second side in the longitudinal direction (an area of the buckling restraining member 20 extending a predetermined distance from the second end surface 20 b on the second side in the longitudinal direction is inserted into the tubular portion 52).
A tapered portion 50 c, whose outer diameter decreases toward the first end surface (corresponding to the tip end) 50 a on the first side in the longitudinal direction, is formed on the outer surface of the tubular portion 52. This configuration gives the impression of smoothly reinforcing the buckling restraining member 20, thereby improving the design.

(Reinforcing-Member Crevice)

Similar to the cap-sleeve crevice 40, the reinforcing-member crevice 60 serves as a joint for installing the brace member 100 on an architectural structure (not illustrated). The reinforcing-member crevice 60 includes a disk-shaped portion 61, a plate-shaped portion 62 disposed on the second end surface of the disk-shaped portion 61, an attachment hole 66 that extends through the plate-shaped portion 62, and a male screw thread 65 formed on the external circumferential surface of the disk-shaped portion 61. Here, the center line of the attachment hole 66 and the center line of the male screw thread 65 perpendicularly cross each other (not geometrically accurately but industrially accurately cross each other).
The reinforcing-member crevice 60 has the same shape as the cap-sleeve crevice 40.
In the above-described configuration, the reinforcing member 50 and the reinforcing-member crevice 60 are separately manufactured and are integrated together with screw connection. However, the present invention is not limited to this configuration. The reinforcing member 50 and the reinforcing-member crevice 60 may be integrated together by mechanical joining such as shrinkage fit or metallurgic joining such as welding. Alternatively, the reinforcing member 50 and the reinforcing-member crevice 60 may be originally manufactured as an integrated unit by, for example, casting.

Operation and Effect

In the brace member 100, the first end portion 21 a of the buckling restraining member 20 on the first side in the longitudinal direction is disposed in the cap sleeve 30. A predetermined area of the buckling restraining member 20 extending from the second end surface 20 b in the longitudinal direction is surrounded with the tubular portion 52 of the reinforcing member 50. Specifically, the tubular portion 52 surrounds the external circumferential surface of the buckling restraining member 20 and the thickness of the tubular portion 52 is not limited. Thus, the outer diameter (and the inner diameter) and the thickness can be increased compared with an existing sleeve (disposed in a gap between the core member and the buckling restraining member), whereby the stiffness can be enhanced. In order to prevent a bending moment from affecting the buckling restraining member 20 to a large extent as a result of the reinforcing-member crevice 60 being eccentrically located due to excessive rotation and deformation, preferably, a length l_kfor which the buckling restraining member 20 is surrounded by the tubular portion 52 and a difference e_kbetween the outer diameter of the buckling restraining member 20 (corresponding to a “bucking restraining member”) and the inner diameter of the reinforcing member 50 has a relationship of e_k/l_k≦0.05.
Here, deformation of a predetermined area of the buckling restraining member 20 extending from the second end surface 20 b on the second side in the longitudinal direction is restricted by the tubular portion 52 of the reinforcing member 50 having high stiffness, whereby the core member 10 is prevented from being buckled (this is separately described in detail).
The outer diameter of the reinforcing member 50 decreases toward the first end surface 50 a (tip end) on the first side in the longitudinal direction (toward the center of the buckling restraining member 20 in the longitudinal direction). Thus, the weight reduction can be enhanced and the design can be improved while the strength at each position in the longitudinal direction is secured.
Both end portions of the core member 10 are respectively connected with screw threads to the cap sleeve 30 and the reinforcing member 50. Thus, by having these screw threads in opposite handedness (for example, the male screw thread 12 a and the female screw thread 31 are right-handed screws and the male screw thread 12 b and the female screw thread 51 are left-handed screws), the distance between the attachment hole 44 and the attachment hole 66 can be adjusted, whereby installation of the brace member 100 can be facilitated.

TABLE 1

	Buckling Restraining	Reinforcing

Core Member

Member

Full Length

	D_S	σ_y	N_y	D_B	t_B	l_K	t_K	Crevice	Gap	e_S	l
Ref.	mm	N/mm²	kN	mm	mm	mm	mm	l_Cmm	e_k mm	mm	mm

No. 1	48.50	622	1149	120.0	28	250	12	326.5	4.0	15.5	2500
No. 2			1149	114.3	25					15.8

(Specimen)

FIG. 2 illustrates a specimen that undergoes a loading test to evaluate the performances of the brace member according to the first embodiment of the present invention and is a sectional view viewed sideways to define the length of each component. Some reference signs are not shown. Table 1 shows the dimensions or the like of each portion of the specimens (No. 1 and No. 2).
In FIG. 2, the outer diameter of the core member 10 of each of the specimen No. 1 and the specimen No. 2 is denoted with “D_S”. The yield point of the core member 10 is denoted with “σ_y”, the product of the cross section of the core member 10 and the yield point σ_yis denoted with “N_y”.
The outer diameter of the buckling restraining member 20 (corresponding to the “buckling restraining member”) is denoted with “D_B”, the thickness of the buckling restraining member 20 is denoted with “t_B”, the distance between the second end surface 20 b of the buckling restraining member 20 on the second side in the longitudinal direction and the center of the attachment hole 66 of the reinforcing-member crevice 60 is denoted with “l_c”, and the distance between the second end surface 20 b of the buckling restraining member 20 on the second side in the longitudinal direction and the first end surface 50 a of the reinforcing member 50 on the first side in the longitudinal direction is denoted with “l_k”. Here, l_khas been described above.
The distance between the center of the attachment hole 44 of the cap-sleeve crevice 40 and the second end surface 30 b of the cap sleeve 30 is denoted with “FlJ”, the distance between the second end surface 30 b of the cap sleeve 30 and the first end surface 50 a of the reinforcing member 50 is denoted with “l_B”, and the distance between the first end surface 50 a of the reinforcing member 50 and the attachment hole 66 of the reinforcing-member crevice 60 is denoted with “MlJ”.
The distance between the center of the attachment hole 44 of the cap-sleeve crevice 40 and the center of the attachment hole 66 of the reinforcing-member crevice 60 is denoted with “l”.
Furthermore, the difference between the outer diameter of the core member 10 and the inner diameter of the buckling restraining member 20 is denoted with “e_S”, and the difference between the outer diameter of the buckling restraining member 20 and the inner diameter of the reinforcing member 50 is denoted with “e_k”. Here, e_khas been described above.
Moreover, the thickness of the reinforcing member 50 at the first end surface 50 a (tip end) on the first side in the longitudinal direction is denoted with “t_K”.

TABLE 2

		Buckling Restraining

Core Member

Member

Full Length

	D_S	σ_y	N_y	D_B	t_B	e_S	l
Ref.	mm	N/mm²	kN	mm	mm	mm	mm

No. 3	46.00	635	1055	114.3	25	18.3	2500

COMPARATIVE EXAMPLE

FIG. 3 illustrates a specimen that undergoes a loading test to evaluate the performances of an existing brace member of a comparative example and is a sectional view viewed sideways to define the length of each component. Table 2 shows the dimensions or the like of each component of a comparative example (No. 3).
In FIG. 3, the outer diameter of a core member 910 of a comparative example (No. 3) 900 is denoted with “D₅”, the outer diameter of a buckling restraining member 20 is denoted with “D_B”, and the thickness of the buckling restraining member 920 is denoted with “t_B”. The yield point of the core member 910 is denoted with “σ_y”, and the product of the cross section of the core member 10 and the yield point σ_yis denoted with “N_y”.
Integrated crevices 940 and 960 (at which female screw threads 941 and 961 are respectively formed) are disposed on end portions 911 a and 911 b (at which male screw threads 912 a and 912 b are respectively formed) of the core member 910. The distance between the center of a connection hole 944 of the first integrated crevice 940 and the center of a connection hole 966 of the second integrated crevice 960 is denoted with “l”.
The first end portion 911 a (at which the male screw thread 912 a is formed) of the core member 910 and a first end portion 921 a (at which a female screw thread 922 a is formed) of the buckling restraining member 920 are connected together with a cap sleeve 930 (at which a female screw thread 931 and a male screw thread 932 are formed).
Furthermore, a tubular sleeve 970 is disposed at a position near the second end portion 911 b of the core member 910. The sleeve 970 is inserted into the buckling restraining member 920 by a distance “L” from a second end surface 920 b of the buckling restraining member 920. Here, the difference between the outer diameter of the sleeve 970 and the inner diameter of a second end portion 921 b of the buckling restraining member 920 is denoted with “e_S”.

(Geometrical Moment of Inertia (Area Moment of Inertia))

From the description given above, the reinforcing member 50 of the specimen No. 2 has an inner diameter of “114.3+4.0=118.3 (mm)” and an outer diameter of greater than or equal to “118.3+2×12=142.3 (mm)”. Thus, the geometrical moment of inertia is greater than or equal to “ten millions (mm⁴)”.
On the other hand, the sleeve 970 of the specimen No. 3, which is a comparative example, has an inner diameter of “46.0 (mm)” and an outer diameter of smaller than or equal to “114.3−2×25=64.3 (mm)”. Thus, the geometrical moment of inertia is smaller than or equal to 0.62 millions (mm⁴).
Specifically, the geometrical moment of inertia of the reinforcing member 50 of aspects of the present invention is approximately 17 times as high (great) as the geometrical moment of inertia of the existing sleeve 970 of a comparative example. Thus, the reinforcing member 50 having such high stiffness restricts out-of-plane deformation of the buckling restraining member 20.

(Cyclic Loading Test)

FIG. 4 has axial force-axial strain charts showing the results of the loading test conducted to evaluate the performances of the brace member according to the first embodiment of the present invention. FIG. 4(a) is a chart for a specimen No. 1 and FIG. 4(b) is a chart for a specimen No. 2. The loading test is a reversed cyclic loading test in which the core member 10 is repeatedly and alternately compressed and stretched.
In FIG. 4(a), firstly, the core member 10 is compressed by 0.25% (the “distance l” between the center of the attachment hole 44 of the cap-sleeve crevice 40 and the center of the attachment hole 66 of the reinforcing-member crevice 60 is reduced by 6.25 mm). At this time, the compressive load and the compressive strain are shown in a first quadrant.
Thereafter, the core member 10 is stretched by 0.25% (the distance l is increased by 6.25 mm). At this time, the tensile load and the tensile strain are shown in a third quadrant.
Furthermore, the core member 10 is compressed by 0.5% (the distance l is reduced by 12.5 mm) and then the core member 10 is stretched by 0.5% (the distance l is increased by 12.5 mm).
Moreover, the core member 10 is compressed by 1.0% (the distance l is reduced by 25 mm) and then the core member 10 is stretched by 1.0% (the distance l is increased by 25 mm). This loading is regarded as one cycle and this cycle is repeated five times.
Finally, the core member 10 is compressed by 2.0% (the distance l is reduced by 50 mm) and then the core member 10 is stretched by 2.0% (the distance l is increased by 50 mm). This loading is regarded as one cycle (or referred to as a “final cycle”, below). This cycle is repeated until the core member 10 is buckled or broken.
The core member 10 of the specimen No. 1 was broken at the fourth stretch after the final cycle had been repeated three times.
In FIG. 4(b), as in the case of the specimen No. 1, the core member 10 of the specimen No. 2 was broken at the fourth stretch after the final cycle had been repeated three times.
Specifically, the core member 10 of neither the specimen No. 1 nor the specimen No. 2 was buckled. This result reveals that the buckling restraining member 20 and the reinforcing member 50 restrict out-of-plane deformation of the core member 10.
FIG. 5 is an axial force-axial strain chart showing the results of the cyclic loading test conducted to evaluate the performances of an existing brace member of a comparative example. As in the case of the specimens No. 1 and No. 2, the cyclic loading test is a reversed cyclic loading test in which the core member 10 is repeatedly and alternately compressed and stretched.
In FIG. 5, the core member 910 of the specimen No. 3 was subjected to one cycle of compression and stretch by 0.1%, two cycles of compression and stretch by 0.25%, and two cycles of compression and stretch by 0.5%. Then, when the core member 910 was compressed by 1.0%, the core member 910 was buckled.
Thus, also through the comparison with the sleeve 970 of an existing brace member 900, the brace member of aspects of the present invention has been proved to be a brace member in which the reinforcing member 50 has high (great) bending strength.

Second Embodiment

FIG. 6 illustrates a brace member according to a second embodiment of the present invention. FIG. 6(a) is a side view of the brace member and FIG. 6(b) is a sectional view of a main portion of the brace member viewed sideways. Portions the same as or corresponding to the portions of the first embodiment are denoted with the same reference signs and some of them are not described herein. The dimensions such as the relative size or thickness of each component are not limited to those illustrated in the drawings.
In FIG. 6, a brace member 200 includes a core member 10, a buckling restraining member 20 through which the core member 10 extends and that surrounds the core member 10 to restrict out-of-plane deformation of the core member 10, a cap sleeve 230 in which a first end portion 11 a of the core member 10 on the first side in the longitudinal direction and a first end portion 21 a of the buckling restraining member 20 on the first side in the longitudinal direction are disposed, a cap-sleeve crevice 40 disposed on the cap sleeve 230 so as to protrude toward a side opposite to a side on which the core member 10 and the buckling restraining member 20 are disposed, the cap-sleeve crevice 40 serving as a joint for installing the brace member 200 on an architectural structure (not illustrated), a reinforcing member 250 in which a second end portion 11 b of the core member 10 on the second side in the longitudinal direction is disposed, and a reinforcing-member crevice 60 disposed on the reinforcing member 250 so as to protrude toward a side opposite to a side on which the core member 10 is disposed, the reinforcing-member crevice 60 serving as a joint for installing the brace member 200 on an architectural structure (not illustrated).
Specifically, the cap sleeve 230 and the reinforcing member 250 of the brace member 200 do not respectively have the tapered portion 30 c and the tapered portion 50 c, which are respectively formed on the outer surface of the cap sleeve 30 and the outer surface of the reinforcing member 50 of the brace member 100 (first embodiment). Except for this point, the brace member 200 is similar to the brace member 100.
Thus, as in the case of the brace member 100, in the brace member 200, the buckling restraining member 20 reinforced with the reinforcing member 250 restricts out-of-plane deformation of the core member 10. Thus, the brace member 200 has high (great) bending strength and is manufactured at low costs.
Specifically, when the cap sleeve 230 and the reinforcing member 250 are manufactured by casting, the die sets are simplified. In addition, the brace member 200 can be manufactured at low costs by performing welding connection between steel pipes or welding connection between a steel pipe and a circular plate (or a disk having a center hole).

Third Embodiment

FIG. 7 illustrates a brace member according to a third embodiment of the present invention. FIG. 7(a) is a side view of the brace member and FIG. 7(b) is a sectional view of a main portion of the brace member viewed sideways. Portions the same as or corresponding to the portions of the first embodiment are denoted with the same reference signs and some of them are not described. The dimensions such as the relative size or thickness of each component are not limited to those illustrated in the drawings.
In FIG. 7, a brace member 300 includes a core member 10, a buckling restraining member 20 through which the core member 10 extends and that surrounds the core member 10 to restrict out-of-plane deformation of the core member 10, a first-side reinforcing member 350 a in which a first end portion 11 a of the core member 10 on the first side in the longitudinal direction and a first end portion 21 a of the buckling restraining member 20 on the first side in the longitudinal direction are disposed, a reinforcing-member crevice 60 disposed on the first-side reinforcing member 350 a so as to protrude toward a side opposite to a side on which the core member 10 and the buckling restraining member 20 are disposed, the reinforcing-member crevice 60 serving as a joint for installing the brace member 300 on an architectural structure (not illustrated), a second-side reinforcing member 350 b in which a second end portion 11 b of the core member 10 on the second side in the longitudinal direction and a second end portion 21 b of the buckling restraining member 20 on the second side in the longitudinal direction are disposed, and a reinforcing-member crevice 60 disposed on the second-side reinforcing member 350 b so as to protrude toward a side opposite to a side on which the core member 10 and the buckling restraining member 20 are disposed, the reinforcing-member crevice 60 serving as a joint for installing the brace member 300 on an architectural structure (not illustrated).
Specifically, the brace member 300 includes a first-side reinforcing member 350 a instead of the cap sleeve 30 of the brace member 100 (first embodiment). The first-side reinforcing member 350 a and the second-side reinforcing member 350 b correspond to the reinforcing member 50.
Thus, the first end portion 21 a of the buckling restraining member 20 is reinforced with the first-side reinforcing member 350 a, in the same manner as the second end portion 21 b reinforced with the second-side reinforcing member 350 b. Except for this point, the brace member 300 is the same as the brace member 100.
Thus, in the brace member 300, the buckling restraining member 20 reinforced with the first-side reinforcing member 350 a and the second-side reinforcing member 350 b restricts out-of-plane deformation of the core member 10. Thus, the brace member 300 has high (great) bending strength and is manufactured at low costs.
Specifically, this configuration eliminates the need to manufacture the cap sleeve 30. Thus, the die set for casting the cap sleeve 30 is not needed and the number of types of components constituting the brace member 300 is reduced, whereby stock control is facilitated.
The brace member 300 includes a pair of reinforcing members 50, but may include a pair of reinforcing members 250 instead of the reinforcing members 50.
Aspects of the present invention achieve a brace member having a high (great) bending strength with a simple structure. The brace member is also usable for core members having cross-sections of various different shapes. Thus, the brace member according to aspects of the present invention is widely usable as a brace member for dealing with various different demands of architectural structures.

REFERENCE SIGNS LIST

- 10 core member
- 11 a first end portion
- 11 b second end portion
- 12 a male screw thread
- 12 b male screw thread
- 20 buckling restraining member
- 20 b second end surface
- 21 a first end portion
- 21 b second end portion
- 22 a male screw thread
- 30 cap sleeve
- 30 a first end surface
- 30 b second end surface
- 30 c tapered portion
- 31 female screw thread
- 32 female screw thread
- 33 cylindrical portion
- 34 female screw thread
- 40 cap-sleeve crevice
- 41 disk-shaped portion
- 42 plate-shaped portion
- 43 male screw thread
- 44 attachment hole
- 50 reinforcing member
- 50 a first end surface (tip end)
- 50 b second end surface
- 50 c tapered portion
- 51 female screw thread
- 52 tubular portion
- 53 disk-shaped portion
- 56 female screw thread
- 60 reinforcing-member crevice
- 61 disk-shaped portion
- 62 plate-shaped portion
- 65 male screw thread
- 66 attachment hole
- 100 brace member (first embodiment)
- 200 brace member (second embodiment)
- 230 cap sleeve
- 250 reinforcing member
- 300 brace member (third embodiment)
- 350 a first-side reinforcing member
- 350 b second-side reinforcing member
- 900 brace member (comparative example)
- 910 core member
- 911 a end portion
- 911 b end portion
- 912 a male screw thread
- 912 b male screw thread
- 920 buckling restraining member
- 920 b end surface
- 921 a end portion
- 921 b end portion
- 922 a female screw thread
- 922 b inner surface
- 930 cap sleeve
- 931 female screw thread
- 932 male screw thread
- 940 integrated crevice
- 941 female screw thread
- 944 connection hole
- 960 integrated crevice
- 961 female screw thread
- 966 connection hole
- 970 sleeve

Claims

1. A brace member, comprising:

a core member;

a buckling restraining member through which the core member extends and that restricts out-of-plane deformation of the core member;

a cap sleeve in which a first end portion of the core member on a first side in a longitudinal direction and a first end portion of the buckling restraining member on the first side in the longitudinal direction are disposed;

a cap-sleeve crevice disposed on the cap sleeve so as to protrude toward a side opposite to a side on which the core member and the buckling restraining member are disposed, the cap-sleeve crevice serving as a joint for installing the brace member on an architectural structure;

a reinforcing member in which a second end portion of the core member on a second side in the longitudinal direction is disposed; and

a reinforcing-member crevice disposed on the reinforcing member so as to protrude toward a side opposite to a side on which the core member is disposed, the reinforcing-member crevice serving as a joint for installing the brace member on the architectural structure,

wherein the reinforcing member surrounds a predetermined area of the buckling restraining member extending from a second end surface on the second side in the longitudinal direction.

2. A brace member, comprising:

an core member;

reinforcing members disposed individually on two ends of the core member in a longitudinal direction; and

reinforcing-member crevices disposed individually on the reinforcing members so as to each protrude toward a side opposite to a side on which the core member is disposed, the reinforcing-member crevices serving as joints for installing the brace member on an architectural structure,

wherein each of the reinforcing members surrounds a predetermined area of the buckling restraining member extending from a corresponding one of end portions of the buckling restraining member in the longitudinal direction.

3. The brace member according to claim 1,

wherein an inner diameter of the reinforcing member in the area in which the reinforcing member surrounds the buckling restraining member is constant in the longitudinal direction, and

wherein an outer diameter of the reinforcing member in the area decreases toward a center of the buckling restraining member in the longitudinal direction.

4. The brace member according to claim 2,