Buckling restraint brace

Abstract

To provide a buckling restraint brace capable of preventing destruction of lumber without strictly restricting a gap between a core material and a restraining material, and capable of reducing the trouble in manufacturing.SOLUTION: A buckling restraint brace 1 includes: a tabular steel core material 3; a spacer 15 arranged on both side surfaces in the plate width direction of the core material 3; a two tabular buckling restraint materials 5 arranged on both side surfaces in the plate thickness direction of the core material 3 via the spacer 15; a buckling restraint material fastening component 17 for fastening the two buckling restraint materials 5 with each other; two wooden bent resistance members 7 arranged on the opposite side from the core material 3 in the buckling restraint material 5; and a bent resistance member fastening component 23 for fastening the bent resistance members 7 with each other apart from the buckling resistant material fastening component 17.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a buckling restrained brace using wood. [Background technology]

[0002] In buildings, braces are sometimes installed as components to resist shear forces during earthquakes. Braces are installed diagonally within the plane of the column-beam framework, and are primarily used to resist shear deformation of a story caused by earthquake loads. During an earthquake, axial tensile and compressive loads are repeatedly applied, so the braces are required to have sufficient strength and deformation capacity to withstand both loads.

[0003] Generally, when an axial compressive load is applied, there is a risk of buckling in a component, which reduces the component's strength and deformation capacity. Since a decrease in strength and deformation capacity can occur in braces due to buckling, there are buckling-restrained braces that consist of a core material that resists earthquake loads and a buckling-restraint material that is arranged to cover the core material to suppress buckling deformation of the core material. 16 and 17 show such a buckling restraint brace 51 arranged within the plane of a frame made up of columns 53 and beams 55.

[0004] The buckling restraint material is required to have sufficient strength to resist bending deformation due to buckling of the core material, and the buckling restraint material or its joints are required to have sufficient strength to resist local compressive forces due to buckling deformation of the core material. Figure 18 is a cross-sectional view of a conventional buckling restrained brace 51 consisting of a steel core material 57 and steel restraint materials 59. Cross-sectional shapes of conventional core material 57 include a plate (see Figure 18(a)), circle (see Figure 18(b)), cross (see Figure 18(c)), H-shape (see Figure 18(d)), etc. The restraint materials 59 covering the core material 57 are often box-shaped (see Figures 18(a), (c), (d)) or circle-shaped (see Figure 18(b)).

[0005] Since the local compressive force due to the buckling deformation of the core material 57 is proportional to the compressive load acting on the core material 57 and the amount of buckling deformation of the core material 57, the larger the gap between the restraining material 59 and the core material 57, the higher the strength required of the restraining material 59. For this reason, some constructions provide a filler 61 such as mortar in the gap between the restraining material 59 and the core material 57 (see FIG. 18(a)). In addition, in order to prevent the axial force of the core material 57 from flowing to the restraint material 59, an unbond material 63 may be applied or attached (see FIG. 18(a)).

[0006] The joints between both ends of the buckling restraint brace 51 and the frame can be of two types: bolt joints 65 shown in FIG. 16, which are joined by bolts, and pin joints 67 shown in FIG. In either case, the core material 57 is made wider near the joint, high-strength steel is used, reinforcing ribs are provided, etc. to increase the strength of the core material 57 and prevent plasticity, so that the joint does not break first. In addition, because the restraining material 59 is made of steel, localized breakage due to contact with the core material 57 is unlikely to occur.

[0007] On the other hand, the use of wood has been promoted in recent years due to the issue of CO2 emissions. Since wood burns up in the event of a fire, it is sometimes used for building columns and beams after being made fireproof by fireproofing. In addition, wood is sometimes used in some parts of steel structures, such as floor slabs, and the use of wood as a restraining material for braces is currently being considered.

[0008] Patent Document 1 proposes a buckling restraint brace that consists of a steel plate-shaped core material and a pair of wooden restraint materials arranged on both sides of the wide surface of the core material, with the two materials joined by bolts at both axial ends. Patent Document 1 also proposes a buckling restraint brace in which a pair of wooden restraint members are arranged to sandwich both sides of the web of the H-shaped cross-section core material.

[0009] Patent Document 2 proposes a buckling restrained brace composed of a steel plate-shaped core material, wooden restraining members arranged on both sides of the core material in the thickness direction, and spacers arranged on both sides of the core material in the width direction. The buckling restrained brace in Patent Document 2 has a spacer thickness equal to or less than the core material thickness so that no gap occurs between the core material and the restraining members, thereby reducing the load on the restraining members caused by buckling of the core material and preventing damage to the restraining members.

[0010] Patent Document 3 also proposes a buckling restraint brace consisting of a steel core material and wooden restraint materials, and like Patent Document 2, it is designed to prevent gaps from occurring between the core material and the restraint materials. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2019-214881 A [Patent Document 2] Patent No. 6942280 [Patent Document 3] Patent Publication No. 2022-53009 Summary of the Invention [Problem to be solved by the invention]

[0012] As described in Patent Documents 1 to 3, buckling restraint braces consisting of a steel core material and wooden restraint materials have been proposed. However, because the wooden restraint materials have low strength, there is a risk that the restraint materials will be damaged when pressed against the core material when the core material buckles.

[0013] As mentioned above, the larger the gap between the restraining material and the core material, the greater the local compressive force and the more likely the restraining material will be damaged, so it is necessary to devise a way to prevent the occurrence of gaps between the core material and the restraining material, as in Patent Documents 2 and 3. However, even if measures are taken to prevent the occurrence of gaps, in reality, there is a high possibility that gaps will occur between the core material and the restraining material due to initial defects or dimensional errors that inevitably occur during manufacturing, and there is a risk that sufficient buckling restraint will not be obtained depending on the size of the gap.

[0014] Therefore, in order to prevent the above gaps from occurring, it is necessary to strictly limit the tolerance of initial irregularities and dimensional errors, and strict manufacturing management is required. Furthermore, if the initial irregularities and dimensional errors are not within the tolerance range, a lot of rework and correction will be required, which will be time-consuming in manufacturing.

[0015] As described above, although the use of wood is being promoted, when wood is used as a restraining material in a buckling restraint brace, measures must be taken to prevent gaps from occurring between the core material and the restraining material in order to ensure sufficient buckling restraint performance, which increases the amount of work required for production, creating a problem.

[0016] The present invention has been made to solve these problems, and its object is to provide a buckling restraint brace that can prevent damage to wood without strictly restricting the gap between the core material and the restraint material, and that can reduce the amount of work required for manufacturing. [Means for solving the problem]

[0017] (1) The buckling restraint brace of the present invention is characterized in comprising a plate-shaped steel core material, spacers arranged on both side surfaces of the core material in the plate width direction, two plate-shaped buckling restraint materials arranged on both side surfaces of the core material in the plate thickness direction via the spacers, buckling restraint material fastening parts that fasten the two buckling restraint materials together, two wooden bending resistance members arranged on the sides of the buckling restraint materials opposite the core material, and bending resistance member fastening parts that fasten the bending resistance members together, separate from the buckling restraint material fastening parts.

[0018] (2) In addition, in the above-mentioned (1), the bending resistance member is characterized in that it is made of a wood material in which a plurality of pieces of wood are glued and laminated in the board width direction of the core material.

[0019] (3) Furthermore, in the above-described (1) or (2), the spacer and the buckling restraint material are made of steel, and the contact surfaces of the spacer and the buckling restraint material are subjected to a friction surface treatment.

[0020] (4) Furthermore, in the above-mentioned (1) or (2), the bending resistance member is provided with a through hole for inserting the bending resistance member fastening part, and the hole diameter of the through hole is equal to the shaft diameter of the bending resistance member fastening part.

[0021] (5) In addition, in the above (4), the bending resistance member fastening part is composed of a bolt and a nut, the head and nut of the bolt are placed in a countersink provided at the end of the through hole of the bending resistance member, and a wooden plug covering the head and nut of the bolt is provided in the countersink.

[0022] (6) Moreover, in the above-mentioned (1) or (2), a lubricant is applied to both sides of the core material.

[0023] (7) Furthermore, in the brace described in (1) or (2) above, the bending resistance member fastening parts are arranged to penetrate the buckling restraint material and the spacer, and the buckling restraint material fastening parts and the bending resistance member fastening parts are arranged at positions offset in the longitudinal direction of the brace.

[0024] (8) Furthermore, in the above-mentioned (1) or (2), the present invention is characterized in that the buckling restraint material is further provided on both side surfaces in the plate width direction with wooden decorative materials for making the buckling restraint material and the spacer invisible from the outside.

[0025] (9) In addition, in the above-mentioned (8), the bending resistance member fastening part is characterized in that it penetrates the decorative material. Effect of the Invention

[0026] In the present invention, two buckling restrained materials are placed on both sides of the core material in the thickness direction via a spacer, and these two buckling restrained materials are fastened together by a buckling restrained material fastening part. As a result, in conventional structures, the wood and the parts that fasten it resist the local compressive force when the core material buckles, but in the present invention, the buckling restrained material and the buckling restrained material fastening parts resist the local compressive force, so the local compressive force applied to the wooden bending resistance member is greatly suppressed. As a result, there is no need to strictly limit the gap between the core material and the buckling restrained material, and the manufacturing effort can be reduced. [Brief description of the drawings]

[0027] [Figure 1] 5(a) is a cross-sectional view of a buckling restraint brace according to an embodiment of the present invention (corresponding to the cross section taken along the arrow DD in FIG. 5(a)). [Diagram 2] 5(a) is a cross-sectional view of a buckling restraint brace according to an embodiment of the present invention (corresponding to the cross section taken along the arrow EE in FIG. 5(a)). [Diagram 3] 3A and 3B are diagrams (part 1) illustrating the internal structure of a buckling restraint brace according to an embodiment of the present invention, in which FIG. 3(a) is a view from the width direction of the core material, and FIG. 3(b) is a view taken along the line AA in FIG. 3(a). [Figure 4] 4A is a view taken in the width direction of the core material, and FIG. 4B is a view taken in the direction of the arrow BB in FIG. 4A. FIG. [Diagram 5] 5A and 5B are diagrams (part 3) for explaining the internal structure of a buckling restraint brace according to an embodiment of the present invention, in which FIG. 5(a) is a view from the width direction of the core material, and FIG. 5(b) is a view taken along the CC arrow in FIG. 5(a). [Figure 6] FIG. 2 shows the buckling restrained brace of FIG. 1 with the bending resistance member fasteners removed. [Figure 7] 5(a) is an explanatory diagram of another embodiment of the bending resistance member (corresponding to the cross section taken along the arrow DD in FIG. 5(a)). FIG. [Figure 8] 5(a) is an explanatory diagram of another embodiment of the bending resistance member (corresponding to a cross section taken along the arrow EE in FIG. 5(a)). [Figure 9] FIG. 2 is an explanatory diagram of another embodiment 1 of the buckling restraint brace according to the present invention. [Figure 10] FIG. 11 is an explanatory diagram of another embodiment 2 of the buckling restraint brace according to the present invention. [Figure 11] FIG. 11 is an explanatory diagram of another embodiment 3 of the buckling restraint brace according to the present invention. [Figure 12] 12A to 12C are diagrams showing the manufacturing process of another embodiment 3 of the buckling restraint brace shown in FIG. 11. [Figure 13] FIG. 11 is an explanatory diagram of another embodiment 4 of the buckling restraint brace according to the present invention. [Figure 14] FIG. 13 is a diagram showing a comparative example according to the embodiment. [Figure 15] FIG. 1 is a diagram showing an example of the invention according to an embodiment. [Figure 16] This is an explanatory diagram of a typical buckling restraint brace installed within the plane of a structural frame (part 1). [Figure 17] This is an explanatory diagram of a typical buckling restraint brace installed within the frame plane (part 2). [Figure 18] FIG. 1 is an explanatory diagram of the core material and restraint material of a typical buckling restraint brace. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] A buckling restraint brace 1 according to this embodiment will be described with reference to Figs. Fig. 1 is a cross-section taken along the line DD in Fig. 5(a), and shows a cross-section of a portion of the buckling restrained brace 1 where the reinforcing rib 13 is not provided. Fig. 2 is a cross-section taken along the line EE in Fig. 5(a), and shows a cross-section of a portion of the buckling restrained brace 1 where the reinforcing rib 13 is provided.

[0029] As shown in Figures 1 and 5, the buckling restrained brace 1 is mainly composed of a steel plate-shaped core material 3, two buckling restrained members 5 arranged to sandwich the core material 3, and two wooden bending resistance members 7 arranged to sandwich the two buckling restrained members 5. To make the internal structure easier to understand, Figure 3 shows only the core material 3, and Figure 4 shows only the core material 3 and the buckling restrained members 5. Each component will be described in detail below.

[0030] <Core material> As shown in FIG. 3, the core material 3 is a steel plate-like body with a rectangular cross section, and the longitudinal ends of the core material 3 form joints 9 for joining the buckling restraint brace 1 to the frame. In this embodiment, both ends of the buckling restrained brace 1 are bolted to the frame with high-strength bolts, so the joints 9 are provided with bolt holes 11. However, in the case of pin joints, the joints 9 are provided with clevises.

[0031] Further, reinforcing ribs 13 are provided on both longitudinal ends of the core material 3 to prevent plasticization. The reinforcing rib 13 is a plate material joined by fillet welding or partial penetration welding so as to be perpendicular to the wide surface of the core material 3, and a cross-sectional area is formed by the core material 3 and the reinforcing rib 13 in the joining area of ​​the reinforcing rib 13 (see Figure 2).

[0032] It is more preferable that a lubricant is applied to both sides of the core material 3. If the sliding properties between the core material 3 and the buckling restrained material 5 are poor, when the core material 3 buckles and comes into contact with the buckling restrained material 5, a longitudinal load is applied to the buckling restrained material 5 in an amount equal to the frictional force, which may accelerate destruction. Therefore, by applying a lubricant to both sides of the core material 3 to improve the sliding properties between the core material 3 and the buckling restrained material 5, the load acting on the buckling restrained material 5 can be reduced.

[0033] <Buckling restraint material> The buckling restraint members 5 are plate-like members arranged on both side surfaces of the core material 3 in the plate thickness direction. Spacers 15 are arranged on both side surfaces of the core material 3 in the plate width direction, and the buckling restraint materials 5 are arranged to sandwich the core material 3 via these spacers 15. The spacer 15 may be a long member extending in the longitudinal direction of the brace, or it may be divided and arranged side by side in the longitudinal direction of the brace.

[0034] The two buckling restraint materials 5, arranged to sandwich the core material 3, are fastened by a buckling restraint material fastening part 17. The buckling restraint material fastening part 17 in this embodiment is composed of a bolt 19 and a nut 21, and the buckling restraint material 5 and the spacer 15 are provided with through holes 5a, 15a, respectively, for passing the bolt 19 through.

[0035] The buckling restraint material fastening parts 17 are provided in one row on each side of the core material 3 so as not to interfere with the core material 3. Since buckling of the core material 3 can occur along its entire length, the buckling restraint material fastening parts 17 are provided along the entire longitudinal length of the buckling restraint material 5 (see FIG. 4).

[0036] Furthermore, slits 5b are provided at the longitudinal ends of the buckling restraint material 5 so as not to interfere with the reinforcing rib 13 (see Fig. 2 and Fig. 4(b)). If the buckling restraint material 5 may interfere with the welded portion between the reinforcing rib 13 and the core material 3, the buckling restraint material 5 may be cut out to match the welded shape.

[0037] Although the present invention does not limit the material of the buckling restraint material 5, since the buckling restraint material 5 resists the buckling deformation of the core material 3, a highly rigid material such as concrete or steel is preferable. For the same reason, it is preferable to use parts with high strength and rigidity such as bolts 19 and nuts 21 for the buckling restraint material fastening parts 17 of the present invention.

[0038] In this embodiment, the thickness of spacer 15 is greater than the thickness of core material 3, which results in a gap S between core material 3 and buckling restrained material 5 (see FIG. 1). By providing gap S between core material 3 and buckling restrained material 5 in this manner, manufacturing errors in core material 3 and buckling restrained material 5 can be absorbed, and manufacturing costs can be reduced. Note that gap S is not essential in the present invention, so the thickness of spacer 15 may be the same as the thickness of core material 3.

[0039] Both the spacer 15 and the buckling restraint material 5 may be made of steel, in which case it is advisable to perform a friction surface treatment on the contact surface between the spacer 15 and the buckling restraint material 5. Specific examples of the friction surface treatment include red rust and providing an uneven surface. By performing the friction surface treatment, it is possible to suppress the slippage between the spacer and the buckling restraint material 5, and higher buckling restraint performance can be expected.

[0040] <Bending resistance member> The bending resistance member 7 is a wooden member arranged on the surface of the buckling restraint member 5 opposite the core material 3 . The two bending resistance members 7, which are arranged so as to sandwich the two buckling restraint materials 5, are fastened by bending resistance member fastening parts 23. A drift pin, a lag screw bolt, or the like can be used as the bending resistance member fastening parts 23, and the bending resistance members 7 are provided with through holes 7a for passing the bending resistance member fastening parts 23 through. As described above, the two buckling restraint members 5 and the two bending resistance members 7 are fastened together by separate fastening parts.

[0041] 1 to 5, the bending resistance member 7 is made wider than the buckling restrained member 5 so that the bending resistance member fastening parts 23 do not interfere with the buckling restrained member 5, and the bending resistance member fastening parts 23 are arranged on the outside of both side surfaces of the buckling restrained member 5. Also, like the buckling restrained member fastening parts 17, the bending resistance member fastening parts 23 are provided in one row on each side in the width direction of the bending resistance member 7, over the entire length of the bending resistance member 7 in the longitudinal direction (see FIG. 5).

[0042] The surface of the bending resistance member 7 that comes into contact with the buckling restraint member 5 is provided with a countersunk groove 7b to avoid interference with the bolts 19 and nuts 21 that fasten the buckling restraint member 5. Similarly to the buckling restraint member 5, a slit 7c is provided at the longitudinal end of the bending resistance member 7 to prevent interference with the reinforcing rib 13 (see Figs. 2 and 5(b)).

[0043] As mentioned above, the buckling restrained material 5 is made of a material, such as concrete or steel, which has higher rigidity than wood, and is therefore highly resistant to localized compressive forces generated by contact with the core material 3, but because it is a plate-like body, it is prone to bending deformation into a bow when compressive force is applied to the core material 3. Therefore, by sandwiching the buckling restrained material 5 between bending resistance members 7, the bending rigidity of the buckling restrained material 5 is reinforced and the above-mentioned bending deformation is prevented.

[0044] From the viewpoint of ensuring the bending resistance of the buckling restraint member 5, it is desirable to make the hole diameter of the through hole 7a of the bending resistance member 7 equal to the shaft diameter of the bending resistance member fastening part 23 (see FIG. 6). By bringing the inner peripheral surface of the through hole 7a into close contact with the bending resistance member fastening part 23 so that no gaps are formed, the two bending resistance members 7 behave as one unit. This increases the bending resistance and provides high bending rigidity, making it possible to suppress bending deformation of the core material 3 when the brace is compressed.

[0045] As described above, in this embodiment, the plate-shaped core material 3 is sandwiched between two plate-shaped buckling restraint materials 5, which are then sandwiched from the outside by two wooden bending resistance members 7, so that the core material 3 does not come into direct contact with the wooden bending resistance members 7. This makes it difficult for localized compressive forces caused by buckling of the core material 3 to act on the wood, preventing damage to the wood. Also, by making the buckling restraint materials 5 into plate shapes, an increase in cross-sectional size is suppressed.

[0046] In comparison with the conventional example in which the core material was directly sandwiched between wooden buckling restraint members, in this embodiment, there is no need to strictly control the gap between the core material 3 and the buckling restraint members 5, reducing manufacturing effort. Furthermore, by making it possible to tolerate a gap between the core material 3 and the buckling restraint material 5, it is possible to intentionally create a gap S as shown in Figure 1 to absorb initial irregularities and dimensional errors, thereby reducing manufacturing costs.

[0047] With regard to providing another member between the core material and the wood, Patent Document 2 describes a method in which a steel plate that comes into close contact with the core material is inserted between the wooden buckling restraint member and the core material, and these are then integrated with bolts or the like (see FIG. 11 of Patent Document 2). However, the above method does not sufficiently prevent damage to the wood. This point will be explained below.

[0048] In the method of Patent Document 2, the core material, the inserted steel plate, and the wooden buckling restraint material are integrated with bolts, so when the core material buckles, a large bending moment acts on the wood between the bolts via the inserted steel plate, and a strong tensile force acts on the bolts. This can cause bending failure of the wood or embedding failure of the wood where the bolt is fastened, which can impair the buckling restraint performance.

[0049] In contrast to this, in the present embodiment, the wood (bending resistance member 7) and the buckling restraint member 5 immediately adjacent to the core material 3 are fastened by separate parts. As a result, the buckling restrained material 5 and buckling restrained material fastening parts 17 located immediately adjacent to the core material 3 provide strong resistance to most of the load acting on the bending resistance member 7 and bending resistance member fastening parts 23 when the core material 3 buckles. This reduces the load acting on the bending resistance member 7 and bending resistance member fastening parts 23, preventing damage to the wood.

[0050] Furthermore, if there is a gap between the core material 3 and the buckling restraint material 5, the load acting on the buckling restraint material 5 when the core material 3 buckles will be large. However, in this embodiment, for the reasons described above, even if a gap S is allowed between the core material 3 and the buckling restraint material 5, the bending resistance member 7 is less likely to be damaged, and high buckling restraint performance can be ensured.

[0051] The bending resistance member 7 may be made of wood material (such as laminated lumber or LVL) in which a plurality of wood pieces 25 are glued and laminated in the width direction of the core material 3, as shown in Figs. Due to its configuration, the bending resistance member 7 of this embodiment is expected to have a large dimension in the width direction of the core material 3. However, by making the width direction of the core material plate and the adhesive lamination direction the same as shown in Figures 7 and 8, it becomes easy to prepare a bending resistance member 7 with a large dimension in the width direction of the core material plate.

[0052] In the above description, an example was given in which a drift pin or a lag screw bolt was used as the bending resistance member fastening part 23, but in another embodiment, the bending resistance member fastening part 23 may be composed of a bolt and a nut. Such an example is shown in FIG. As shown in FIG. 9, a buckling restrained brace 27 which is another aspect 1 of this embodiment has two bending resistance members 7 fastened together by a bending resistance member fastening component 23 made up of a bolt 29 and a nut 31.

[0053] The bending resistance member 7 is provided with a through hole 7a for inserting the bolt 29, and a countersink 7d is formed at the end of the through hole 7a. The head and nut 31 of the bolt 29 are disposed in the countersink 7d, and a wooden plug 33 for covering the head and nut 31 of the bolt 29 is provided in the countersink 7d. As described above, when a bolt 29 and a nut 31 are used as the bending resistance member fastening part 23, by providing a countersink 7d and a wooden plug 33 in the bending resistance member 7, the head of the bolt 29 and the nut 31 are not visible from the outside, improving the design.

[0054] In the above description, the bending resistance member fastening parts 23 are provided so as to pass through the widthwise outer sides of the buckling restrained material 5 and the spacer 15, but in another embodiment, the bending resistance member fastening parts 23 may be provided so as to penetrate the buckling restrained material 5 and the spacer 15. Such an example is shown in FIG. Fig. 10(a) is a view of a buckling restraint brace 35 according to another aspect 2 of this embodiment, viewed from the width direction of the core material 3. Fig. 10(b) is a view corresponding to the cross section taken along the arrow FF in Fig. 10(a), and Fig. 10(c) is a view corresponding to the cross section taken along the arrow GG in Fig. 10(a).

[0055] The buckling restrained member 5 and spacer 15 of the buckling restrained brace 35 have through holes 5c, 15b for passing through bending resistance member fastening parts 23 in addition to through holes 5a, 15a for passing through the buckling restrained member fastening parts 17 (see FIG. 10(c)). The two bending resistance members 7 are fastened together by the bending resistance member fastening parts 23 that pass through the buckling restrained member 5, spacer 15 and bending resistance member 7.

[0056] In the examples described above, the buckling restraint material fastening parts 17 and the bending resistance member fastening parts 23 were arranged in the same position in the longitudinal direction of the brace, but in the example of Fig. 10, the two parts are arranged in positions offset in the longitudinal direction of the brace so as not to interfere with each other. Note that in all examples other than the example of Fig. 10, the buckling restraint material fastening parts 17 and the bending resistance member fastening parts 23 are illustrated as being arranged in the same position in the longitudinal direction of the brace to make the configuration easier to understand, but there is no problem if they are arranged in different positions in the longitudinal direction of the brace.

[0057] In this embodiment, the bending resistance member fastening parts 23 can be arranged near both side surfaces of the core material 3 in the plate width direction, so that the dimensions of the bending resistance member 7 in the plate width direction of the core material 3 can be reduced, which is expected to lead to miniaturization and weight reduction. In addition, when viewed from the width direction of the core material 3, the bending resistance member fastening parts 23 are not exposed, improving the design.

[0058] In this example, the bending resistance member fastening part 23 penetrates the buckling restraint material 5, but since this is the same as the previously described example in that the buckling restraint material 5 and the bending resistance member 7 are each fastened by separate parts, this does not impair the load reduction effect acting on the bending resistance member 7.

[0059] As described above, the example in Fig. 10 improves the design because the bending resistance member fastening parts 23 are not exposed, but the distance between the buckling restraint material fastening parts 17 and the bending resistance member fastening parts 23 tends to be close, so care must be taken to prevent them from interfering with each other. Also, if there is not enough space, it may be difficult to use the embodiment in Fig. 10. Therefore, as another aspect for improving the design, wooden decorative materials may be further provided on both side surfaces in the board width direction of the buckling restrained member 5 to hide the buckling restrained member 5 and the spacers 15 from the outside. Such an example is shown in Fig. 11. A buckling restrained brace 37, which is another aspect 3 of this embodiment, has a similar configuration to the buckling restrained brace 1 in Fig. 1, but as shown in Fig. 11, a wooden decorative member 39 is provided between the upper and lower bending resistance members 7. The decorative member 39 may be a long member that is long in the longitudinal direction of the brace, or it may be divided and arranged side by side in the longitudinal direction of the brace (see Fig. 12(a)).

[0060] The size of the decorative material in the thickness direction of the core material is made equal to or larger than the sum of the thickness of the spacer 15 and the thickness of the two buckling restraint materials 5 so as to cover and conceal the buckling restraint material 5, spacer 15 and bending resistance member fastening parts 23.

[0061] By providing decorative material 39 on both sides of the buckling restraint material 5 in the plate width direction, specifically further outside the position where the bending resistance member fastening parts 23 are provided, the buckling restraint material 5, spacer 15 and bending resistance member fastening parts 23 are not exposed in the core plate width direction, improving the design.

[0062] Although the decorative material 39 may simply be fitted between the two bending resistance members 7, it is preferable to bond it to either one of the bending resistance members 7, as this improves manufacturability. This point will be explained with reference to Figure 12. Figure 12(a) is a diagram showing the state during the manufacturing process of the buckling restrained brace 37 in Figure 11, and Figure 12(b) is a cross-sectional view taken along the arrow HH in Figure 12(a). As shown in Fig. 12, by joining the decorative material 39 to one of the bending resistance members 7 (the lower bending resistance member 7 in Fig. 12), the position of the decorative material 39 can be fixed during production, improving production efficiency. The decorative material 39 may be joined to the bending resistance member 7 by screws, nails, or adhesives.

[0063] While the above is an example in which the decorative material 39 is provided on the outside of the bending resistance member fastening parts 23, it is also possible to configure the bending resistance member fastening parts 23 to penetrate the decorative material 39. Such an example is shown in Figure 13. In a buckling restrained brace 41, which is Alternative Example 4 of this embodiment, the thickness of the decorative material 39 is thicker than in the example of Figure 11, and the decorative material 39 is formed with a through hole 39a for passing the bending resistance member fastening parts 23 through. As shown in FIG. 13, the two bending resistance members 7 are fastened together by a bending resistance member fastening part 23 which penetrates the decorative material 39 and the bending resistance members 7. In this example, as in the example of FIG. 11, the buckling restraint members 5, spacers 15 and bending resistance member fastening parts 23 are not exposed in the width direction of the core plate, improving the design. Furthermore, by fastening the decorative material 39 with the bending resistance member fastening parts 23, the decorative material 39 is integrated with the opposing bending resistance member 7, thereby improving the rigidity of the bending resistance member 7. EXAMPLES

[0064] We investigated the stiffening ability of the present invention against local loads caused by buckling of the core material. Specifically, we investigated the difference in stiffening ability depending on whether or not there is a fastening member that fastens the buckling restraint members 5 together. Hereinafter, we will explain this with reference to Figs. 14 and 15. 14 shows a state in which a local load acts on a buckling restrained brace 43, which is a comparative example. In the buckling restrained brace 43, the buckling restrained member 5 and the bending resistance member 7 are fastened by the same fastening part 45. The fastening part 45 is composed of a bolt 47 and a nut 49. Figure 15 shows a state in which a local load is applied to the buckling restrained brace 1 of Figure 1, which is an example of the present invention. As described above, in the buckling restrained brace 1, the buckling restrained member 5 and the bending resistance member 7 are fastened by separate fastening parts.

[0065] First, the behavior of the comparative example in FIG. 14 when a local load is applied will be described. 14, when the buckling restrained material 5 and the bending resistance member 7 are fastened by the same fastening part 45, if a push-out force is applied to the buckling restrained material 5 and the bending resistance member 7 by the buckled core material 3, the fastening part 45 that fastens them together will resist this. At this time, a tensile force acts on the fastening part 45, and local stress acts on the contact area between the fastening part 45 and the bending resistance member 7. This may cause the bolt 47 or nut 49 of the fastening part 45 to sink into the bending resistance member 7, causing the bending resistance member 7 to break.

[0066] Furthermore, as the fastening parts 45 resist the extrusion force of the core material 3, bending deformation occurs in the bending resistance member 7 and the buckling restraint member 5 with the fastening parts 45 as the fulcrum, and a strong bending moment acts between the fastening parts 45 on both sides in the width direction of the core material 3. Such a bending moment may destroy the bending resistance member 7. For the reasons described above, in the configuration of the comparative example, there is a risk that the wooden bending resistance member 7 will break when the core material buckles.

[0067] Here, in a certain cross section, if the local extrusion force due to buckling of the core material 3 is P and the distance between the fastening parts 45 on both sides of the width of the core material 3 is u, the load acting on each fastening part 45 can be expressed as P / 2, and the bending moment acting on the bending resistance member 7 can be expressed as P / 2 × u / 2 = Pu / 4.

[0068] Next, the behavior of the example of the invention shown in FIG. 15 when a local load acts thereon will be described. 15, when the buckling restraint material 5 and the bending resistance member 7 are fastened by separate parts, the buckling restraint material fastening parts 17 provide strong resistance to the pushing force caused by the buckling of the core material 3. Therefore, the bending resistance member 7 bears the load excluding the load borne by the buckling restraint material fastening parts 17.

[0069] Therefore, if the load borne by each buckling restraint material fastening part 17 is Pa / 2, the load borne by each bending resistance member fastening part 23 is (P-Pa) / 2, and the bending moment acting on the bending resistance member 7 is (P-Pa)u / 4. As described above, in the example of the present invention, the force acting on the bending resistance member fastening part 23 and the bending moment acting on the bending resistance member 7 are reduced compared to the comparative example, so that the bending resistance member 7 is less likely to be destroyed, which is preferable.

[0070] In particular, if the buckling restraint material 5 and the buckling restraint material fastening part 17 have sufficient strength and rigidity against the local extrusion force P, the bending resistance member 7 and the bending resistance member fastening part 23 may be mechanisms (drift pins, round bars) that provide almost no resistance to the local extrusion force P, and sufficient stiffening performance can be obtained as long as the bending resistance member fastening part 23 prevents the pair of bending resistance members 7 from shifting in the axial direction of the core material. [Explanation of symbols]

[0071] 1. Buckling Restrained Brace 3 Core material 5 Buckling restraint material 5a through hole 5b Slit 5c through hole 7 Bending resistance members 7a Through hole 7b Seat digging 7c Slit 7d. Seat digging 9 Joint 11 Bolt holes 13 Reinforcing rib 15 Spacer 15a through hole 15b Through hole 17 Buckling restraint fastening parts 19 Volts 21 Nut 23 Bending resistance member fasteners 25 Wood Piece 27 Buckling Restrained Brace (Other Form 1) 29 Volts 31 Nut 33 Wood plug 35 Buckling Restrained Brace (Other Form 2) 37 Buckling Restrained Brace (Other Form 3) 39 Cosmetic materials 39a through hole 41 Buckling Restrained Brace (Other Form 4) 43 Buckling restrained brace (Comparative example) 45 Fastening parts 47 Volts 49 Nut 51 Buckling restrained brace (conventional example) 53 Pillars 55 Beam 57 Core material 59 Restraint material 61 Filling material 63 Unbonded material 65 Bolted joint 67 Pin joint S Gap

Claims

1. A buckling restrained brace comprising: a plate-shaped steel core material; spacers arranged on both sides of the core material in the plate width direction; two plate-shaped buckling restraint materials arranged on both sides of the core material in the plate thickness direction via the spacers; buckling restraint material fastening parts that fasten the two buckling restraint materials together; two wooden bending resistance members arranged on the sides of the buckling restraint material opposite the core material; and bending resistance member fastening parts that fasten the bending resistance members together, separate from the buckling restraint material fastening parts.

2. 2. The buckling restraint brace according to claim 1, wherein the bending resistance member is made of a wood material in which a plurality of pieces of wood are glued and laminated in the width direction of the core material.

3. 3. The buckling restraint brace according to claim 1 or 2, characterized in that the spacer and the buckling restraint material are made of steel, and the contact surfaces between the spacer and the buckling restraint material are frictionally treated.

4. 3. The buckling restraint brace according to claim 1, characterized in that the bending resistance member has a through hole for inserting the bending resistance member fastening part, and the hole diameter of the through hole is equal to the shaft diameter of the bending resistance member fastening part.

5. 5. The buckling restraint brace of claim 4, wherein the bending resistance member fastening components are comprised of bolts and nuts, the bolt heads and nuts being placed in counterbores provided at the ends of the through holes in the bending resistance member, and the counterbores are provided with wooden plugs to cover the bolt heads and nuts.

6. 3. The buckling restraint brace according to claim 1 or 2, characterized in that a lubricant is applied to both sides of the core material.

7. 3. A buckling restrained brace as described in claim 1 or 2, characterized in that the bending resistance member fastening parts are arranged to penetrate the buckling restraint material and the spacer, and the buckling restraint material fastening parts and the bending resistance member fastening parts are arranged at positions offset in the longitudinal direction of the brace.

8. The buckling restraint brace according to claim 1 or 2, further comprising wooden decorative materials on both side surfaces of the buckling restraint material in the plate width direction to prevent the buckling restraint material and spacers from being seen from the outside.

9. 9. The buckling restrained brace of claim 8, wherein the bend resistant member fasteners extend through the facing material.

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