Buckling-restrained brace

Abstract

To provide a buckling-restrained brace that, even when the male threads at the ends of the core material are rolled threads and there is a relatively large step difference between the rolled threads and the axial body of the core material, can suppress the increase in the stiffening force that can act on the inner tube when the core material buckles, and eliminates the need to increase the plate thickness of the inner tube. [Solution] The buckling-restrained brace 100 has a steel core material 10 comprising an axially extending shaft-shaped body 11 and male threads 13 which are rolled threads with a larger diameter than the outer diameter of the shaft-shaped body 11; a steel inner tube 40 that surrounds the shaft-shaped body 11 and the area up to the middle of the male threads 13 at both ends; a plurality of steel annular outer spacers 30 arranged at axial intervals around the inner tube 40; a steel outer tube 50 arranged around the plurality of outer spacers 30; and a steel connecting fitting 60 that is joined to other members by having female threads 67 that screw into the male threads 13, with an annular inner spacer 20 interposed between the shaft-shaped body 11 and the inner tube 40.

Description

[Technical Field]

[0001] The present invention relates to a buckling-restrained brace. [Background Art]

[0002] Various types of buckling-restrained braces are applied to building frames to improve the earthquake resistance and wind resistance of buildings, and one example is proposed in Patent Document 1.

[0003] In the buckling-restrained brace described in Patent Document 1, two split core members each having one end fixed to a central fixing ring portion are loosely inserted into an outer pipe for stiffening the core members with a gap from the inner surface of the outer pipe. An end coupler, which has higher rigidity than the split core members, is joined to the end portions of the split core members, guided by the inner surface of the outer pipe, and is movable in the pipe axial direction, is provided inside the end portion of the outer pipe. The end portions of the split core members are joined to a structural member via the end couplers.

[0004] One end of each of two inner pipes is fixed to the fixing ring portion in the same manner as the split core members, and a clearance that allows mutual movement along the axial direction is provided between the inner peripheral surface of the inner pipe and the outer peripheral surface of the split core member. This clearance is dimensioned such that the outer peripheral surface of the split core member can abut against and frictionally contact the inner peripheral surface of the inner pipe, so that the inner pipe can stiffen the split core member that can contract and deform in a wavy manner in the axial direction under the action of compressive force.

[0005] A plurality of ring-shaped spacers are provided on the outer side of the inner pipe at appropriate intervals along the axial direction thereof, the outer pipe is provided on the outer side of the plurality of spacers, a screw hole is formed at one end of the end coupler in the axial direction, and by screwing a joining screw portion formed at the other end of each split core member into the screw hole, each end coupler is joined to the other end of each split core member to form the buckling-restrained brace.

[0006] Here, it is stated that the joining screw portion of the split core member is formed to have a larger diameter than the outer diameter of the split core member by rolling. [Prior Art Literature] [Patent Literature]

[0007] [Patent Document 1] Japanese Patent Publication No. 2010-242460 [Overview of the project] [Problems that the invention aims to solve]

[0008] In a configuration such as the buckling-restrained brace described in Patent Document 1, in which an inner tube is arranged around a core material and an outer tube is arranged via multiple spacers, buckling of the core material and inner tube can be effectively suppressed by restraining the core material with the inner tube and restraining the inner tube with the outer tube.

[0009] Incidentally, in the case of a split core material as described in Patent Document 1, where the connecting threads at the ends are rolled threads, unlike machined threads, the outer diameter of the rolled threads is larger than that of the general part of the core material. Therefore, if the inner diameter of the inner tube is set to match the outer diameter of the rolled threads, the clearance (gap) between the general part of the core material and the inner tube may become excessively large. In this case, when the core material buckles due to the applied compressive force, the stiffening force acting from the core material to the inner tube becomes too large, making it necessary to prepare an inner tube with a plate thickness (thickness) that can withstand this large stiffening force. This will be outlined with reference to Figures 10A and 10B. Note that Figure 10B is an excerpt from the Steel Structure Vibration Control Design Guidelines 2014 (Architectural Institute of Japan).

[0010] As shown in Figure 10A, when an inner tube P with an inner diameter of φ2 corresponding to the outer diameter of a rolled screw (not shown) at the end of a core material C is arranged around the general part of the core material C with an outer diameter of φ1, an excessive gap S / 2 (overall gap S in the radial direction) may occur between the inner tube P and the general part of the core material C.

[0011] As shown in Figure 10B, the core material C is subjected to the maximum compressive force during an earthquake. d N max This action causes the general part of core material C to buckle to length l. nWhen buckling occurs, an out-of-plane stiffening force B acts on the inner tube P from the buckling peak. As the gap S increases, this stiffening force B also increases, making it necessary to install an inner tube P with a plate thickness that can withstand a large stiffening force B.

[0012] In the buckling-restrained brace described in Reference 1, although the threaded portion of the joint between the segmented core material is described as a rolled thread, there is no description of a solution to the above problem.

[0013] The present invention has been made in view of the above problems, and relates to a buckling-restrained brace in which an inner tube is arranged around a core material, an outer tube is arranged around the inner tube via an outer spacer, and a male thread at the end of the core material is screwed into a female thread of a connecting fitting. The present invention aims to provide a buckling-restrained brace that can suppress the increase in the stiffening force that can act on the inner tube when the core material buckles, even when the male thread at the end of the core material is a rolled thread and there is a relatively large step (gap) between the rolled thread and the axial body of the core material, thereby eliminating the need to increase the plate thickness of the inner tube. [Means for solving the problem]

[0014] To achieve the above objective, one embodiment of the buckling-restrained brace according to the present invention is: A steel core material comprising an axially extending shaft-shaped body and male threads, which are rolled threads with a larger diameter than the outer diameter of the shaft-shaped body, at both ends of the shaft-shaped body, The core material includes a steel inner tube that encloses the shaft-shaped body and the area up to the middle of the male threads at both ends, Around the inner tube, a plurality of annular steel outer spacers are arranged at intervals in the axial direction, A steel outer tube is arranged around a plurality of the aforementioned outer spacers, It has a steel connecting fitting that has a female thread that screws into the male thread and is joined to another member, The present invention is characterized by having an annular internal spacer interposed between the axial body and the inner tube.

[0015] According to this embodiment, an annular inner spacer is interposed between the shaft-shaped main body of the core material and the inner pipe, so that the step (gap) between the rolled screw at the end of the core material and the shaft-shaped main body can be eliminated or reduced by the inner spacer. Therefore, the increase in stiffening force when the shaft-shaped main body of the core material buckles can be suppressed, and it is not necessary to increase the plate thickness of the inner pipe.

[0016] Furthermore, by covering (enclosing) the rolled screw of the core material with a steel inner pipe up to a midpoint position in the rolled screw of the core material, which can be a structural weak point where compressive force and tensile force act directly even within the core material, the rolled screw can be stiffened by the inner pipe.

[0017] Furthermore, in another embodiment of the buckling-restrained brace according to the present invention, said inner spacer is formed of a plurality of annular split spacers split in the axial direction, around said core material, said plurality of split spacers are arranged in said axial direction with inter-spacer gaps, and part of said outer spacers are aligned in said inter-spacer gaps.

[0018] According to this embodiment, the inner spacer is formed of a plurality of annular split spacers split in the axial direction, the split spacers are arranged in the axial direction with inter-spacer gaps, and the outer spacers are aligned in the inter-spacer gaps, which facilitates the attachment of the inner spacer around the core material.

[0019] Furthermore, in another embodiment of the buckling-restrained brace according to the present invention, said split spacers are formed of a plurality of small split spacers split in the circumferential direction of the annular shape.

[0020] According to this embodiment, each split spacer is formed of a plurality of small split spacers split in the circumferential direction of the annular shape, which further facilitates the attachment of the inner spacer around the core material.

[0021] Furthermore, in another embodiment of the buckling-restrained brace according to the present invention, An end gap is provided between the end of the divided spacer located on the joint fitting side and the male screw.

[0022] According to this aspect, since the end gap is provided between the end of the divided spacer located on the joint fitting side and the male screw of the core member, it is possible to suppress the divided spacer on the joint fitting side from inhibiting the expansion and contraction of the end side of the shaft-shaped main body of the core member.

[0023] Further, in another aspect of the buckling-restrained brace according to the present invention, An adhesive resin material is adhered around the shaft-shaped main body, and the inner spacer is adhered to an outer periphery of the resin material.

[0024] According to this aspect, the adhesive resin material is adhered around the shaft-shaped main body, and the inner spacer is adhered to the outer periphery of the resin material, whereby the inner spacer (divided spacer or subdivided spacer) can be fixed around the shaft-shaped main body via the adhesive resin material. Furthermore, the adhesive resin material can function as a lubricant between the shaft-shaped main body of the core member and the inner spacer, can reduce the frictional force at the interface between the shaft-shaped main body and the inner spacer, makes it difficult for axial force to be transmitted from the shaft-shaped main body to the inner spacer when the shaft-shaped main body is compressed, and can suppress an increase in load acting on the inner spacer due to the transmitted axial force.

[0025] Further, in another aspect of the buckling-restrained brace according to the present invention, The inner pipe is formed by a plurality of divided inner pipes divided in the axial direction, Around the inner spacer, the plurality of divided inner pipes are arranged in the axial direction with gaps between inner pipes, and a first elastic body is interposed in the gaps between the inner pipes.

[0026] According to this embodiment, the inner tube is formed by a plurality of divided inner tubes that are divided in the axial direction, and the plurality of divided inner tubes are arranged around the inner spacer with gaps between the inner tubes in the axial direction, and a first elastic body is interposed in the gaps between the inner tubes. As a result, an inner tube can be formed with any number (for example, 2 to 5) of divided inner tubes, the total length of which is the length to the midpoint of a pair of rolled screws at both ends of the core material, and the total length of the inner tube made up of a plurality of divided inner tubes can be adjusted to a desired length by the first elastic body interposed in the gaps between the inner tubes, thereby forming an inner tube that corresponds to the expansion and contraction of the core material.

[0027] For example, nuts (end nuts) are locked at intermediate positions of the rolled threads at both ends of the core material, and the first elastic body interposed in the gap between the inner tubes is interposed between adjacent segmented inner tubes in a slightly compressed position. With both ends of multiple segmented inner tubes positioned between two end nuts, the inner tubes consisting of multiple segmented inner tubes and the first elastic body can be arranged without axial displacement.

[0028] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, One of the outer spacers is installed on the outer circumference of the inner spacer located in the gap between the inner pipes. One outer spacer is installed on each end of the outer circumference of the divided inner tube on both sides of the gap between the inner tubes. The first elastic body is interposed between the outer spacer located in the gap between the inner tubes and the end of the divided inner tube located to its side.

[0029] According to this embodiment, one of the outer spacers is installed on the outer circumference of an inner spacer in the gap between inner tubes, and a first elastic body is interposed between the outer spacer in the gap between inner tubes and the end of the divided inner tube located to its side. This allows the divided inner tube located to its side to be positioned without axial displacement by utilizing the outer spacer.

[0030] Here, "one of the outer spacers is placed on the outer circumference of the inner spacer in the gap between the inner pipes" means that a divided spacer exists in the gap between the inner pipes, and one of the outer spacers is placed around this divided spacer. In other words, it means that there is no gap between spacers in the gap between the inner pipes, and this prevents the axial body of the core material from being exposed and becoming a structurally weak point without being restrained by the inner spacers or inner pipes when a gap between spacers exists in the gap between the inner pipes.

[0031] Furthermore, other embodiments of the buckling-restrained brace according to the present invention include: The end of the divided inner pipe located on the side of the connecting hardware is locked to the end of the connecting hardware, or locked to an end nut that is screwed into the middle of the male screw.

[0032] According to this embodiment, the ends of the divided inner tubes located on the connecting hardware side are locked to end nuts that are screwed into the ends of the connecting hardware or to the intermediate positions of the male threads (rolled threads), thereby enabling the entire inner tube, consisting of multiple divided inner tubes and the first elastic body between them, to be arranged around the core material without axial displacement.

[0033] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The spacing between the outer spacers in the axial direction is set to be less than or equal to the support spacing required to prevent the inner tube from bending and buckling.

[0034] According to this embodiment, the spacing between the outer spacers in the axial direction is set to be less than or equal to the support spacing required to prevent the inner tube from bending and buckling, thereby effectively suppressing buckling of the inner tube (divided inner tube) by the outer spacers.

[0035] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The present invention is characterized in that a slip-preventing material is interposed between a plurality of the aforementioned external spacers to prevent the external spacers from shifting in the axial direction.

[0036] According to this embodiment, by interposing a slip-preventing material between the outer spacers, even when the outer spacers are loosely fitted around the outer circumference of the inner spacers or the outer circumference of the inner tube (divided inner tube), axial displacement of each outer spacer can be effectively prevented.

[0037] Here, an example of a slip-prevention material is one in which a pipe cover made of urethane foam or similar material is cut in half or into thirds, and then fitted between adjacent outer spacers and secured with tape or the like to form a single pipe cover.

[0038] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The aforementioned connecting hardware has a connecting portion that is joined to another member and a housing portion that accommodates the end of the outer pipe. The female screw is provided at the bottom of the housing section. A second elastic body is interposed between the end of the outer tube and the bottom of the housing.

[0039] According to this embodiment, the connecting hardware has a connecting portion that is joined to another member and a housing portion that accommodates the end of the outer tube, and when the male thread (rolled thread) of the core material is screwed into the female thread at the bottom of the housing portion, the outer tube is housed in the housing portion, and a second elastic body is interposed between the end of the outer tube and the bottom of the housing portion, so that the outer tube can be positioned without axial displacement relative to the connecting hardware at both ends.

[0040] Furthermore, in other embodiments of the buckling-restrained brace according to the present invention, The device is characterized in that it has an insertion hole through which the divided inner tube, located on the side of the connecting hardware, is inserted, and a steel closing plate is provided to close the end of the outer tube, and the second elastic body is interposed between the closing plate and the end of the connecting hardware.

[0041] According to this embodiment, because a second elastic body is interposed between the steel closing plate that closes the end of the outer pipe and the end of the connecting hardware, one end of the second elastic body can be stably fixed to any location on the closing plate, compared to the case where one end of the second elastic body is directly fixed to the annular end of the outer pipe, which has limited fixing positions. [Effects of the Invention]

[0042] As can be understood from the above explanation, the buckling-restrained brace of the present invention relates to a buckling-restrained brace in which an inner tube is arranged around a core material, an outer tube is arranged around the inner tube via an outer spacer, and the male threads at the ends of the core material are screwed into the female threads of a connecting fitting. In this case, even if the male threads at the ends of the core material are rolled threads and there is a relatively large step (gap) between the rolled threads and the axial body of the core material, it is possible to suppress the increase in the stiffening force that can act on the inner tube when the core material buckles, and it becomes unnecessary to increase the thickness of the inner tube. [Brief explanation of the drawing]

[0043] [Figure 1] This is a longitudinal cross-sectional view of an example of a buckling-restrained brace according to an embodiment. [Figure 2] This is a perspective view of an example of a core material forming a buckling-restrained brace according to the embodiment. [Figure 3] This is a perspective view of an example of an internal spacer forming a buckling-restrained brace according to the embodiment. [Figure 4] This is a perspective view of an example of an external spacer forming a buckling-restrained brace according to the embodiment. [Figure 5] This is a perspective view of an example of an inner tube forming a buckling-restrained brace according to the embodiment. [Figure 6] This is a perspective view of an example of an outer tube forming a buckling-restrained brace according to the embodiment. [Figure 7] This is a perspective view of an example of a connecting hardware that forms a buckling-restrained brace according to the embodiment. [Figure 8]This is an enlarged view of section VIII in Figure 1, showing a state in which an outer spacer is installed in the gap between adjacent divided inner tubes, and a first elastic body is interposed between the divided inner tube and the outer spacer. [Figure 9] This is an enlarged view of section IX in Figure 1, showing the state in which the ends of the outer tube and the inner tube are housed inside the connecting hardware, and the ends of the core material are fixed in place. [Figure 10A] This is a longitudinal cross-sectional view of the general portion of the inner tube and the core material inside it in a conventional buckling-restrained brace. [Figure 10B] This diagram simulates a state where the core material buckles due to the applied compressive force, thereby applying a stiffening force to the inner tube. [Modes for carrying out the invention]

[0044] Hereinafter, an example of a buckling-restrained brace according to the embodiment will be described with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0045] [Buckling-restrained brace according to an embodiment] An example of a buckling-restrained brace according to the embodiment will be described with reference to Figures 1 to 9. Here, Figure 1 is a longitudinal cross-sectional view of an example of a buckling-restrained brace according to the embodiment. Figures 2 to 7 are perspective views of an example of a core material, inner spacer, outer spacer, inner tube, outer tube, and connecting hardware forming a buckling-restrained brace according to the embodiment, respectively. Furthermore, Figure 8 is an enlarged view of section VIII in Figure 1, showing a state in which an outer spacer is installed in the gap between adjacent divided inner tubes and a first elastic body is interposed between the divided inner tube and the outer spacer. Figure 9 is an enlarged view of section IX in Figure 1, showing a state in which the ends of the outer tube and the inner tube are housed inside the connecting hardware and the end of the core material is fixed.

[0046] The buckling-restrained brace 100 comprises a steel core 10 extending in the axial direction, a steel inner tube 40 disposed around the core, a plurality of steel annular outer spacers 30 disposed at axial intervals around the core 10 and inner tube 40, a steel outer tube 50 disposed around the plurality of outer spacers 30, and steel connecting hardware 60 disposed at both ends of the core 10 so as to surround the outer tube 50.

[0047] As clearly shown in Figure 2, the core material 10 comprises an axially extending shaft-shaped body 11 and male threads 13, which are rolled threads, located at both ends of the shaft-shaped body 11 and having an outer diameter φ2 that is larger than the outer diameter φ1 of the shaft-shaped body. Each pair of male threads 13 has an end nut 15 screwed onto it.

[0048] As clearly shown in Figure 5, the inner tube 40 is formed by a plurality of (four in the illustrated example) divided inner tubes 41, 42 (a divided inner tube 41 on the central side and a divided inner tube 42 on the end side) which are divided in the axial direction. Each divided inner tube 41, 42 is arranged with an inner tube gap 45 between them, and a first elastic body 48, such as a coil spring, is interposed in the inner tube gap 45.

[0049] The total length of the inner tube 40 can be adjusted as desired by multiple (three in the illustrated example) first elastic bodies 48. In the example shown in Figure 1, each first elastic body 48 is slightly compressed, and the total length is set to L1. The divided inner tubes 42 at the ends are locked to end nuts 15 that are screwed onto the rolled threads 13 of the core material 10, thereby maintaining the total length of the inner tube 40 at L1 and positioning the inner tube 40 around the core material 10 in a position where it does not shift axially.

[0050] As shown in Figure 1, the divided inner tube 42 at the end is secured to the end nut 15 located midway along the rolled thread 13, so it is positioned to surround the rolled thread 13 up to a certain point. This configuration allows the rolled thread 13 of the core material 10, which can be a structural weak point due to direct compressive and tensile forces acting on it, to be reinforced by the inner tube 40 (and the divided inner tube 42 at its end) surrounding it.

[0051] In the illustrated example, the inner tube 40 is formed by four divided inner tubes 41 and 42, with the central divided inner tube 41 being relatively longer. However, the number of divided inner tubes and the length of each divided inner tube can vary in configurations other than those shown in the illustration.

[0052] As shown in Figure 2, a step is created between the central shaft-shaped body 11 that forms the core material 10 and the rolled threads 13 at both ends due to the difference in their outer diameters. When the inner tube 40 is placed around the core material 10, a gap is created between the shaft-shaped body 11 and the inner tube 40 due to this step. As explained with reference to Figures 10A and 10B, this gap causes the core material C to withstand the maximum compressive force during an earthquake. d N max The general part of the core material C buckles to length l. n When buckling occurs, an out-of-plane stiffening force B acts on the inner pipe P from the buckling peak. Since this stiffening force B increases with increasing gap S, it becomes necessary to install an inner pipe P with a plate thickness that can withstand a large stiffening force B.

[0053] Therefore, in order to eliminate or reduce the gap between the axial body 11 of the core material 10 and the inner tube 40, an annular steel inner spacer 20 is interposed in the gap between the axial body 11 and the inner tube 40, as shown in Figures 1 and 3.

[0054] The internal spacer 20 is formed by a plurality of (three in the illustrated example) annular divided spacers 21 that are divided in the axial direction, and the plurality of divided spacers 21 are arranged around the axial body 11 of the core material 10 with spacer gaps 25 between them in the axial direction.

[0055] Each divided spacer 21 is further formed by a plurality of (three in the illustrated example) smaller divided spacers 23 that are divided in the annular circumferential direction.

[0056] The internal spacer 20 is formed by a plurality of divided spacers 21 that are divided in the axial direction, and a spacer gap 25 is provided between each divided spacer 21, so that the spacer gap 25 can absorb the axial expansion and contraction of the axial body 11 of the core material 10 during an earthquake.

[0057] Furthermore, as shown in Figure 9, an end gap 28 is provided between the end of the divided spacer 21 located on the connecting hardware 60 side and the male screw 13 of the core material 10. This end gap 28 prevents the divided spacer 21 on the connecting hardware side from hindering the expansion and contraction of the end side of the axial body 11 of the core material 10.

[0058] Furthermore, since the internal spacer 20 is formed by multiple segmented spacers 21, and each segmented spacer 21 is formed by multiple sub-segmented spacers 23 divided in the circumferential direction, the mounting of the shaft-shaped body 11 around it is improved.

[0059] When attaching each small segment spacer 23 to the periphery of the shaft-shaped body 11 of the core material 10, an adhesive resin material 18 (see Figures 8 and 9) is provided around the shaft-shaped body 11, and each small segment spacer 23 is attached to the periphery of the shaft-shaped body 11 via the resin material 18, thereby fixing the segment spacers 21 around the shaft-shaped body 11.

[0060] Here, butyl rubber, silicone rubber, etc., can be used as the adhesive resin material 18. The adhesive resin material 18 can also function as a lubricant between the shaft-shaped body 11 of the core material 10 and the inner spacer 20, and has the effect of reducing the frictional force at the interface between the shaft-shaped body 11 and the inner spacer 20.

[0061] As a result, when the shaft-shaped body 11 is compressed, the axial force transmitted from the shaft-shaped body 11 to the inner spacer 20 becomes less likely, and the increase in the load acting on the inner spacer 20 due to the transmitted axial force can be effectively suppressed.

[0062] As shown in Figure 4, the outer spacer 30 includes an outer spacer 30B with an inner diameter of φ3 that is loosely fitted around the inner spacer 20 (inserted with a slight margin), and an outer spacer 30A with an inner diameter of φ4 that is loosely fitted around the inner pipe 40.

[0063] As shown in Figure 8, one outer spacer 30B is placed on the outer circumference of the inner spacer 20 in the gap 45 between the inner tubes, one outer spacer 30A is placed on the outer end of each of the divided inner tubes 41 on both sides of the gap 45 between the inner tubes, and a first elastic body 48 is interposed between the outer spacer 30B in the gap 45 and the end of the divided inner tube 41 to its side, so that each divided inner tube 41 and each outer spacer 30A, 30B are arranged around the axial body 11.

[0064] As shown in Figure 8, since there are no divided inner tubes 41 and 42 in the gap 45 between the inner tubes, in order to stiffen the axial body 11 of the core material 10, the gap 45 between the inner tubes is configured such that the divided spacers 21 are exposed without the gap 25 between the spacers 21.

[0065] Furthermore, as shown in Figure 1, the spacing L2 between the outer spacers 30 is set to be less than or equal to the support spacing required to prevent the inner pipe 40 from bending and buckling, thereby creating a configuration in which buckling of the inner pipe 40 can be suppressed by each outer spacer 30.

[0066] As shown in Figures 1 and 8, a displacement prevention material 70 is interposed between each outer spacer 30 to prevent axial displacement of each outer spacer 30.

[0067] This anti-slip material 70 can be formed, for example, by arranging divided covers, such as pipe covers, which are cut in half or into thirds, around the divided inner pipe 41, and fixing each divided cover to itself with tape or the like.

[0068] As shown in Figures 1 and 9, an outer pipe 50 is arranged around a plurality of outer spacers 30, and a closing plate 55 having an insertion hole 56 through which a divided inner pipe 42 is inserted is joined to the end 52 of the outer pipe 50.

[0069] Furthermore, connecting hardware 60 is attached to the rolled threads 13 of the core material 10, surrounding the end of the outer pipe 50, and is bolted to other members (not shown) (such as brackets provided on the inside of corners of building frames, etc.).

[0070] The connecting hardware 60 has a connecting portion 61 that is joined to another member and a housing portion 65 that accommodates the end of the outer pipe 50.

[0071] The bottom 66 of the housing section 65 is provided with a female screw 67, into which the male screw 13 of the core material 10 is screwed, and the end nut 15 that is screwed onto the male screw 13 is locked to the bottom 66.

[0072] The joint 61 comprises a cross-shaped rib 62 formed by assembling steel plates in a cross shape, and a joining plate 63 joined to the end of the cross-shaped rib 62. The joining plate 63 is provided with bolt holes 63a through which bolts are inserted when bolted to other members.

[0073] In the position where the end of the outer tube 50 is housed in the housing section 65, a second elastic body 58, such as a coil spring, is interposed between the bottom 66 of the housing section 65 and the closing plate 55.

[0074] In this way, the end of the outer tube 50 is aligned with the connecting hardware 60 joined to the core material 10 via the second elastic body 58, thereby preventing axial displacement of the outer tube 50.

[0075] Furthermore, since one end of the second elastic body 58 is fixed to the closing plate 55 joined to the end 52 of the outer tube 50, one end of the second elastic body 58 can be fixed in a stable position. As is clear from Figure 9, if the closing plate 55 were not present, it would be necessary to fix one end of the second elastic body 58 within the narrow area of ​​the end 52 of the outer tube 50, and there would be a risk that the second elastic body 58 would slip into the inside of the outer tube 50 if it shifted, but this problem is eliminated by the closing plate 55.

[0076] In the illustrated example of the buckling-restrained brace 100, an annular inner spacer 20 is interposed between the axial body 11 of the core material 10 and the inner tube 40. This eliminates or reduces the step between the rolled screw 13 at the end of the core material 10 and the axial body 11, thereby suppressing an increase in the stiffening force when the axial body 11 of the core material 10 buckles, and eliminating the need to increase the plate thickness of the inner tube 40.

[0077] Furthermore, by covering the rolled threads 13 of the core material 10, which can become structurally weak points due to direct compressive and tensile forces, with a steel inner tube 40 (divided inner tube 42), the rolled threads 13 can be reinforced by the inner tube 40.

[0078] Furthermore, the inner tube 40 is formed by a plurality of divided inner tubes 41, 42 which are divided in the axial direction, and the plurality of divided inner tubes 41, 42 are arranged around the inner spacer 20 with gaps 45 between them in the axial direction, and a first elastic body 48 is interposed in the gaps 45 between the inner tubes. As a result, an inner tube 40 with a total length equal to the length to the midpoint of the pair of rolled screws 13 at both ends of the core material 10 can be formed by any number of divided inner tubes 41, 42, and the total length of the inner tube 40 made up of a plurality of divided inner tubes 41, 42 can be adjusted to a desired length by the first elastic body 48 interposed in the gaps 45 between the inner tubes, thereby forming an inner tube 40 that corresponds to the expansion and contraction of the core material 10.

[0079] Here, the design method for the buckling-restrained brace 100 is outlined as follows: the design method involves restraining the buckling of the core material 10 against the compressive force acting on the buckling-restrained brace 100, and designing the inner tube 40 and outer tube 50 so that overall buckling does not occur.

[0080] In the design of the inner tube 40, as previously described, the spacing L2 between the outer spacers 30 is set to be less than or equal to the support spacing required to prevent the inner tube 40 from bending and buckling.

[0081] In designing the outer tube 50, the thickness and specifications are set so that the outer tube 50 does not buckle with respect to the total length of the buckling-restrained brace 100.

[0082] Furthermore, other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0083] 10: Core material 11: Shaft-shaped body 13: Male screw (rolled screw) 15: End nut 18: Resin material (adhesive resin material) 20: Internal spacer 21: Split Spacer 23: Small split spacer 25: Gap between spacers 28: End gap 30, 30A, 30B: External spacers 40: Inner tube 41,42: Split inner tube 45: Gap between inner tubes 48: First elastic body 50:Outer tube 52: End face 55: Blockage plate 58: Second elastic body 60: Connecting hardware 61: Joint 62: Cross-shaped ribs 63: Joining plate 63a: Bolt hole 65: Detention Unit 66;bottom 67: Female thread 70: Anti-slip material 100: Buckling-restrained brace

Claims

1. A steel core material comprising an axially extending shaft-shaped body and male threads, which are rolled threads with a larger diameter than the outer diameter of the shaft-shaped body, at both ends of the shaft-shaped body, The core material includes a steel inner tube that encloses the shaft-shaped body and the area up to the middle of the male threads at both ends, Around the inner tube, a plurality of annular steel outer spacers are arranged at intervals in the axial direction, A steel outer tube is arranged around a plurality of the aforementioned outer spacers, It has a steel connecting fitting that has a female thread that screws into the male thread and is joined to another member, A buckling-restrained brace characterized in that an annular internal spacer is interposed between the axial body and the inner tube.

2. The internal spacer is formed by a plurality of annular divided spacers that are divided in the axial direction. The buckling-restrained brace according to claim 1, characterized in that a plurality of the divided spacers are arranged around the core material in the axial direction with gaps between the spacers, and some of the outer spacers are aligned with the gaps between the spacers.

3. The buckling-restrained brace according to claim 2, characterized in that the divided spacer is formed by a plurality of small divided spacers divided in an annular circumferential direction.

4. The buckling-restrained brace according to claim 3, characterized in that an end gap is provided between the end of the divided spacer located on the connecting hardware side and the male screw.

5. The buckling-restrained brace according to claim 3, characterized in that an adhesive resin material is bonded around the shaft-shaped body, and the internal spacer is bonded to the outer circumference of the resin material.

6. The inner tube is formed by a plurality of divided inner tubes that are divided in the axial direction. The buckling-restrained brace according to claim 1 or 2, characterized in that, around the internal spacer, the plurality of divided internal tubes are arranged in the axial direction with gaps between the internal tubes, and a first elastic body is interposed in the gaps between the internal tubes.

7. One of the outer spacers is installed on the outer circumference of the inner spacer located in the gap between the inner pipes. One outer spacer is installed on each end of the outer circumference of the divided inner tube on both sides of the gap between the inner tubes. The buckling-restrained brace according to claim 6, characterized in that the first elastic body is interposed between the outer spacer in the gap between the inner tubes and the end of the divided inner tube located to its side.

8. The buckling-restrained brace according to claim 7, characterized in that the end of the divided inner tube located on the side of the connecting hardware is locked to the end of the connecting hardware, or locked to an end nut screwed into the middle of the male screw.

9. The buckling-restrained brace according to claim 8, characterized in that the distance between the outer spacers in the axial direction is set to be less than or equal to the support distance required to prevent the inner tube from bending and buckling.

10. The buckling-restrained brace according to claim 9, characterized in that a slip-preventing material is interposed between a plurality of the outer spacers to prevent the outer spacers from slipping in the axial direction.

11. The aforementioned connecting hardware has a connecting portion that is joined to another member and a housing portion that accommodates the end of the outer pipe. The female screw is provided at the bottom of the housing section. The buckling-restrained brace according to claim 10, characterized in that a second elastic body is interposed between the end of the outer tube and the bottom of the housing.

12. The buckling-restrained brace according to claim 11, characterized in that it has an insertion hole through which the divided inner tube located on the side of the connecting hardware is inserted, and a steel closing plate is provided to close the end of the outer tube, and the second elastic body is interposed between the closing plate and the end of the connecting hardware.

Images