Buckling restrained brace
The buckling restraint brace addresses structural imbalance and damage issues by using a steel core with wooden restraints and strategically placed slits to absorb seismic energy and prevent slit damage, ensuring balanced and durable wooden structures.
Patent Information
- Application Number
- JP2024008005
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-01-23
- Publication Date
- 2025-08-04
AI Technical Summary
Conventional buckling restraint braces used in wooden buildings face issues with structural imbalance due to the weight and visibility of metal or concrete components, leading to potential damage at the slits in wooden restraints from supplementary stiffness forces during earthquakes, and there is a lack of effective solutions to prevent such damage.
A buckling restraint brace design featuring a steel core material with narrow and wide portions, reinforced by orthogonal ribs, surrounded by wooden restraints with strategically positioned slits, ensuring a safe distance from the boundary to prevent damage from supplementary stiffness forces during earthquakes.
The design effectively suppresses damage to the wooden restraints by absorbing seismic energy and preventing stress concentration at the slits, maintaining structural integrity and appearance balance in wooden buildings.
Smart Images
Figure 2025113714000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a buckling restraint brace.
Background Art
[0002] Conventionally, as a brace for forming a building structure (column-beam structure, roof structure, etc.), a buckling restraint brace with buckling prevention measures has been applied. As the buckling restraint brace, there are various stiffening forms such as a form in which only a steel plate stiffens around a steel core material, a form in which a steel core material is stiffened with RC (Reinforced Concrete), and a form in which a steel core material is covered with steel and mortar.
[0003] By the way, recently, efforts have been made to improve the fire resistance and seismic resistance of wooden buildings (wooden houses, wooden warehouses, wooden stadiums, etc.). Wooden buildings inherently have advantages such as a high degree of freedom in floor plans and designs, a soothing effect by natural wood, a humidity control effect of wood, and generally lower construction costs compared to steel-frame or RC structures depending on the building use such as houses. However, the improvement of the above-mentioned fire resistance and seismic resistance is one of the factors that have increased the attention of wooden buildings including wooden buildings. When incorporating the above-mentioned conventional buckling restraint brace into the structure of such a wooden building, a wooden column or beam and a buckling restraint brace having a metal or concrete stiffening material will coexist, and it is inevitable that the appearance will be unbalanced.
[0004] Therefore, a measure of covering the entire buckling restraint brace with a wooden or paper panel or the like so that the metal or concrete stiffening material cannot be visually recognized from the outside can be considered, but this measure requires a great deal of labor and there is a concern about an increase in construction costs. In addition, since conventional buckling restraint braces use a lot of metal, concrete, mortar, etc., they tend to be heavy, and it is structurally unbalanced to attach a heavy buckling restraint brace to lightweight wooden beams and columns that make up a wooden building.
[0005] Here, Patent Document 1 proposes a buckling restraint brace suitable for being incorporated and used within the framework of wooden buildings including wooden structures. Specifically, it is a buckling restraint brace having a core material and a pair of restraint materials arranged along both sides of the core material. The core material is formed of steel, the pair of restraint materials are formed of wood, and laminated lumber is applied to these restraint materials. The laminated lumber is a buckling restraint brace in which laminas are laminated in parallel with the core material.
Prior Art Documents
Patent Documents
[0006]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0007] According to the buckling restraint brace described in Patent Document 1, the pair of restraint materials formed of wood can improve the strength against overall buckling of the buckling restraint brace.
[0008] By the way, as a form of the core material forming the buckling restraint brace, it has a narrow-width portion where the width of the wide-width surface is relatively narrow on the central side in the longitudinal direction, and a wide-width portion where the width of the wide-width surface is relatively wide on the end side in the longitudinal direction. Reinforcing ribs are joined to the wide-width portion on the end side to present a cross-sectional cruciform shape, and there is a form in which the cruciform end portion on this cross-section is bolted to gusset plates, brackets, etc. of the framework. By making the end side a wide-width portion and further making it cross-sectional cruciform in this way, the rigidity of the end portion of the core material becomes relatively high, and it is suppressed that the end portion joined to the framework yields in advance during an earthquake, and by plasticizing the narrow-width portion on the central side, it becomes a buckling restraint brace excellent in earthquake energy absorption performance. More specifically, due to the displacement of the framework during an earthquake, a compressive force acts on the core material, and the earthquake energy is absorbed by the deformation of the narrow-width portion of the core material in a higher-order buckling mode.
[0009] When the deformation of the above-described higher-order buckling mode occurs in the narrow portion of the core material, a supplementary stiffness force (pressing force) often acts on the wooden restraint that surrounds the core material. Therefore, it is necessary to consider the indentation strength that resists the above-described supplementary stiffness force for the wooden restraint that surrounds the core material. Incidentally, the wooden restraint is generally provided over the entire area of the narrow portion of the core material and the range up to the middle position of the wide portion. When the end portion of the core material exhibits the above-described cross-shaped cross section, a slit is generally provided at the position corresponding to the reinforcing rib in the wooden restraint in order to prevent interference between the wooden restraint and the reinforcing rib.
[0010] When the core material has the narrow portion and the wide portion described above, since the boundary region between the narrow portion and the wide portion is a cross-sectional change region, stress is likely to concentrate, and the above-described supplementary stiffness force also tends to increase. However, when the slit in the wooden restraint is close to this boundary region, there is a problem that damage such as cracking is likely to occur in the vicinity of the slit, which is a structurally weak part in the wooden restraint compared to other regions, due to the acting supplementary stiffness force. Incidentally, the buckling restraint brace described in Patent Document 1 does not disclose a solution means for eliminating the damage of the wooden restraint corresponding to the end portion side of such a core material.
[0011] The present invention has been made in view of the above problems, and relates to a buckling restraint brace in which a core material includes a narrow portion that absorbs seismic energy and wide portions at both ends thereof, a reinforcing rib is joined to the wide portion, and a wooden restraint that surrounds the core material includes a slit for preventing interference with the reinforcing rib. An object of the present invention is to provide a buckling restraint brace capable of suppressing damage to the vicinity of the slit of the wooden restraint due to the supplementary stiffness force acting from the core material.
Means for Solving the Problems
[0012] In order to achieve the above object, one aspect of the buckling restraint brace according to the present invention is a steel plate-shaped core material, and a wooden restraint formed by a pair of wooden restraint members disposed so as to face at least two wide surfaces of the core material. The core material includes a narrow-width portion where the width of the wide-width surface is relatively narrow on the central side in the longitudinal direction thereof, and includes a wide-width portion where the width of the wide-width surface is relatively wide on the end side in the longitudinal direction thereof. Reinforcing ribs orthogonal to the wide-width surface are joined to the wide-width surfaces at the longitudinal ends of the core material, presenting a cross-sectional cross shape. Among the pair of restraining materials, slits that do not interfere with the reinforcing ribs are provided at positions corresponding to the reinforcing ribs. It is characterized in that the distance between the end of the slit and the boundary between the wide-width portion and the narrow-width portion is separated by an amount of elongation of the narrow-width portion or more.
[0013] According to this aspect, the distance between the end of the slit provided at the position corresponding to the reinforcing rib in the wooden restraint and the boundary between the wide-width portion and the narrow-width portion of the core material is separated by an amount of elongation of the narrow-width portion during an earthquake (for example, during a major earthquake). As a result, it is possible to suppress the additional stiffness force applied to the wooden restraint due to the deformation of the higher-order buckling mode generated in the boundary or the boundary region in the vicinity thereof from acting on the slit or its vicinity, and it is possible to suppress the wooden restraint from being damaged.
[0014] When compressive force or tensile force is generated in the core material during a major earthquake, the narrow-width portion of the core material mainly deforms. Due to the compressive force, deformation of the higher-order buckling mode occurs in the narrow-width portion, and due to the tensile force, the narrow-width portion elongates, and these are repeated. As described above, in the boundary region between the narrow-width portion and the wide-width portion of the core material, the additional stiffness force acting on the wooden restraint due to stress concentration also increases. Therefore, even if the narrow-width portion elongates, by separating the boundary region and the end of the slit (longitudinal end) of the wooden restraint by an amount of elongation of the narrow-width portion or more, it is possible to suppress the additional stiffness force caused by the deformation of the higher-order buckling mode in the boundary region from acting on the slit or its vicinity.
[0015] In this aspect, a steel core material is surrounded by a wooden restraint body formed by a pair of wooden restraint members. With this configuration, even when the buckling restraint brace of this aspect is applied to the structure of a wooden building, there is no risk of giving a disproportionate appearance to the structural components. Here, the restraint member may be formed of a solid wood material or may be formed of a laminated wood material in which laminas are laminated.
[0016] In this aspect, at the longitudinal ends of the core material, since a reinforcing rib orthogonal to the wide surface of the core material is joined to present a cruciform cross-section, when the buckling restraint brace is attached to a gusset plate or the like such that the wide surface of the core material is arranged parallel to the building surface, by having a reinforcing rib orthogonal to the wide surface parallel to the building surface at the end of the core material, the rigidity in the direction outside the building surface can be increased at the end of the core material. In the gusset plate of the surface where the core material with a cruciform cross-section is attached in this way, a fin stiffener is attached to the gusset plate, and the core material of the buckling restraint brace, the gusset plate, the reinforcing rib, and the fin stiffener are joined by high-tensile bolts or the like via a splice plate respectively.
[0017] Also, in another aspect of the buckling restraint brace according to the present invention, the elongation amount is characterized in that it is set by the product of the longitudinal length L of the narrow portion or L / 2 which is half of it and a predetermined strain.
[0018] According to this aspect, by setting the elongation amount (Δ) to the product of the longitudinal length L of the narrow-width portion or L / 2, which is half of it, and a predetermined strain (δ), the elongation amount of the narrow-width portion during an earthquake can be set reasonably and relatively easily. Since there are a pair of wide-width portions on both sides of the narrow-width portion and there are slits at positions corresponding to the reinforcing ribs in both wide-width portions of the wooden restraint, the overall elongation amount Δ of the narrow-width portion becomes L×δ. Therefore, it suffices that the distance between the slits on the left and right and the boundary is ensured to be L / 2×δ or more. However, by setting the distance between both the left and right slits and the boundary to be L×δ or more, a design on the safe side is achieved. That is, in setting the elongation amount, whether to adopt L or L / 2 is up to the judgment of the designer. Incidentally, for example, a length between L / 2 and L may be set, but in this aspect, L or L / 2 is applied as a reasonable and easy-to-understand length.
[0019] Further, in another aspect of the buckling-restrained brace according to the present invention, the wide-width portion includes a first wide-width portion at the end and a second wide-width portion that is relatively narrower in width than the first wide-width portion, the second wide-width portion is continuous with the narrow-width portion, the end of the slit is at an intermediate position of the second wide-width portion, and bolt holes through which bolts are inserted when bolt-joined to the structure are provided in the first wide-width portion.
[0020] According to this aspect, since the wide-width portion includes a first wide-width portion at the end and a second wide-width portion that is relatively narrower in width than the first wide-width portion, and bolt holes through which bolts are inserted when bolt-joined to the structure are provided in the first wide-width portion, the reinforcing rib joined to the wide-width portion and the bolt holes provided in the wide-width portion can be separated as much as possible. As a result, when inserting bolts into the bolt holes and bolt-joining to brackets or the like of the structure, interference between the tool and the reinforcing rib can be suppressed.
[0021] Further, in another aspect of the buckling-restrained brace according to the present invention, The wooden restraint body is further provided with a pair of wooden side plates that connect the corresponding ends of the pair of restraint members to each other.
[0022] According to this aspect, since the wooden restraint body further has a pair of wooden side plates that connect the corresponding ends of the pair of restraint members to each other, the core material can be surrounded by a wooden restraint body having a strong closed structure. Here, the wooden restraint members and the side plates can be connected by an adhesive, nails, screws, bolts, or a plurality of these.
Effect of the Invention
[0023] As can be understood from the above description, according to the buckling restraint brace of the present invention, the core material has a narrow portion that absorbs seismic energy and wide portions at both ends thereof, reinforcing ribs are joined to the wide portions, and a wooden restraint body that surrounds the core material is provided with slits for preventing interference with the reinforcing ribs. Regarding the buckling restraint brace, it is possible to suppress damage to the vicinity of the slits of the wooden restraint body due to the supplementary stiffness acting from the core material.
Brief Description of the Drawings
[0024]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Embodiments for Carrying Out the Invention
[0025] Hereinafter, the buckling restraint brace according to the embodiment will be described with reference to the accompanying drawings. In the present specification and the drawings, substantially the same components may be denoted by the same reference numerals to omit redundant description.
[0026] [Buckling Restraint Brace According to the Embodiment] First, with reference to FIGS. 1 to 6, an example of the buckling restraint brace according to the embodiment will be described. Here, FIG. 1 is a perspective view showing an example of a core material forming the buckling restraint brace according to the embodiment, and FIG. 2 is a perspective view of an example of the buckling restraint brace according to the embodiment. Further, FIG. 3 is a cross-sectional view taken along the arrow III-III of FIG. 2 and cut at a position in the middle of the thickness of the restraint material, and FIG. 4 is a longitudinal sectional view of the end portion of the buckling restraint brace according to the embodiment taken along the arrow IV-IV of FIG. 2. Furthermore, FIG. 5 is a longitudinal sectional view of the central portion of the buckling restraint brace according to the embodiment taken along the arrow V-V of FIG. 2, and FIG. 6 is an enlarged view of a VI portion of FIG. 5.
[0027] As shown in FIG. 1, the core material 10 is formed of an elongated plate-shaped flat steel, has a narrow-width portion 11 with a relatively narrow width of the wide-width surface 10a on the central side in the longitudinal direction, and has a wide-width portion 12 with a relatively wide width of the wide-width surface 10a on the end side in the longitudinal direction.
[0028] More specifically, the wide-width portion 12 includes a first wide-width portion 12A at the end and a second wide-width portion 12B that is relatively narrower than the first wide-width portion 12A. From the first wide-width portion 12A to the second wide-width portion 12B, it is processed so that the width changes in a tapered shape. Here, the wide-width portion 12 may also have a form in which it does not have two wide-width portions with different widths and has only one wide-width portion (only the wide-width portion 12A).
[0029] From the first wide-width portion 12A to the second wide-width portion 12B, at the central position of the wide-width surface 10a, a reinforcing rib 14 perpendicular to the wide-width surface 10a is joined by welding, and the wide-width portion 12 has a cross-shaped cross-section.
[0030] Since the core material 10 has a narrow-width portion 11 on the central side in its longitudinal direction and a wide-width portion 12 on the end side in the longitudinal direction, the narrow-width portion 11 on the central side can be made into an area (plasticization area) where it is easy to plasticize.
[0031] Also, in the illustrated example, particularly because a reinforcing rib 14 is attached to the wide-width portion 12 and the rigidity of the wide-width portion 12 is further increased, the narrow-width portion 11 becomes easier to plasticize. The additional bending moment acting on the core material 10 will be effectively absorbed in the narrow-width portion 11, which is the plasticization area.
[0032] Also, the wide-width portion 12 and the reinforcing rib 14 are each provided with bolt holes 12a and 14a for bolt connection via a splice plate to a gusset plate provided on the structural surface or a fin stiffener (see FIG. 7) attached to the gusset plate, as will be described below.
[0033] When the buckling restraint brace 100 is attached to the gusset plate such that the wide-width surface 10a of the core material 10 is arranged parallel to the structural surface of the building, by having the reinforcing rib 14 perpendicular to the wide-width surface 10a parallel to the structural surface at the end of the core material 10, the rigidity in the out-of-plane direction at the end of the core material 10 can be increased.
[0034] The core material 10 is preferably formed of a steel material with a low yield point such as SN material (rolled steel for building structures) or LYP material (extra-low yield point steel material). The earthquake energy absorption property due to the yield of the core material 10 becomes good.
[0035] In the illustrated core material 10, the length between the boundaries P, P of the wide-width portions 12 and the narrow-width portions 11 on the left and right (that is, the longitudinal length of the narrow-width portion 11) is L.
[0036] As shown in FIG. 2, a pair of wooden restraint members 30 are arranged so as to sandwich a pair of wide-width surfaces 10a of the core material 10, and a pair of side plates 40 made of wood are connected to the ends of the pair of restraint members 30, whereby a wooden restraint body 20 is formed, and a buckling restraint brace 100 is formed in which the core material 10 is surrounded by the wooden restraint body 20.
[0037] Here, the connection between the restraint member 30 and the side plate 40 is performed by any one or a plurality of types of adhesives, nails, screws, bolts. Note that the wooden restraint body may be formed only by a pair of restraint members (a form without side plates). In this form, the pair of restraint members are connected to each other by an adhesive, a nail, a screw, or the like.
[0038] A slit 35 is provided at the longitudinal end of the restraint member 30, and a part of the reinforcing rib 14 joined to the end of the core material 10 is loosely fitted in the slit 35 to prevent interference between the restraint member 30 and the reinforcing rib 14.
[0039] The restraint member 30 is a laminated wood formed by laminating a plurality of laminas and bonding them to each other. As will be described in detail below, the cross-sectional area, cross-sectional rigidity, Young's modulus, etc. of the wooden restraint body 20 are set so as to prevent the overall buckling of the buckling restraint brace. And this Young's modulus is determined by the material of the wood. Examples of the wood material include cypress, red pine, larch, fir, and spruce.
[0040] The wooden restraint body 20 can surround the long and narrow portion 11 of the steel core material 10 to form a buckling restraint brace 100 with excellent appearance design. Here, although not shown in the figure, there are protrusions on both wide surfaces 10a of the narrow portion 11 of the core material 10, and there are grooves at positions corresponding to the protrusions on the wide surface of the restraint material 30. The protrusions are respectively fitted into the grooves so that the displacement of the core material 10 with respect to the restraint material 30 can be prevented.
[0041] As shown in FIG. 3, a gap G1 with a predetermined width is provided between the slit 35 of the restraint material 30 and the reinforcing rib 14. Due to this gap G1, when the surface where the buckling restraint brace 100 is attached is greatly deformed in the strong axis direction or the weak axis direction, the deformation of the core material 10 (and the reinforcing rib 14) is absorbed at this gap G1, and the reinforcing rib 14 acts on the restraint material 30 to suppress the damage of the wooden restraint body 20.
[0042] Also, in the end region of the core material 10, as shown in FIG. 3, a gap G2 is provided between the wide portion 12, the side plate 40, and the restraint material 30. Due to this gap G2, similar to the gap G1, the deformation of the core material 10 is absorbed, and the wide portion 12 of the core material 10 acts on the side plate 40 or the restraint material 30 to suppress the damage of the wooden restraint body 20.
[0043] On the other hand, in the central region of the core material 10, as shown in FIG. 4, the wide surface 10a of the core material 10 abuts against and is restrained by the wide surface of the restraint material 30. In contrast, a spacer 50 for preventing the displacement of the core material 10 toward the side plate 40 is interposed between the narrow surface 10b of the core material 10 and the side plate 40. Here, the spacer 50 may be fixed to one of the restraint materials 30 with nails, screws, etc. Furthermore, although not shown in the figure, these members may be joined to each other by a plurality of bolts passing through the pair of restraint materials 30 and the spacer 50.
[0044] As shown in FIGS. 5 and 6, when the distance between the end 35a (the end in the longitudinal direction) of the slit 35 provided in the restraint material 30 and the boundary P between the wide portion 12 and the narrow portion 11 is Δ, the distance Δ is set to be equal to or greater than the elongation amount of the narrow portion 11.
[0045] More specifically, the distance Δ is set by the product of the longitudinal length L of the narrow portion 11 or L / 2 which is half thereof, and a predetermined strain (δ), and the strain is set in the range of, for example, 0.015 (1.5% of the length L) to 0.03 (3% of the length L).
[0046] In this way, by setting a distance Δ greater than or equal to the elongation amount of the narrow portion 11 between the end portion 35a of the slit 35 and the boundary P between the narrow portion 11 and the wide portion 12, damage such as cracking in the slit 35 and its vicinity can be suppressed. That is, when a compressive force or a tensile force is generated in the core material 10 during a major earthquake, the narrow portion 11 of the core material 10 mainly deforms. Due to the compressive force, deformation in the higher-order buckling mode occurs in the narrow portion 11, and due to the tensile force, the narrow portion 11 elongates, and these are repeated. However, at the boundary P between the narrow portion 11 and the wide portion 12 of the core material 10 and in its peripheral region, the supplementary stiffening force acting on the wooden restraint body 20 also increases due to stress concentration. By separating the boundary P and the end portion 35a of the slit 35 of the restraint member 30 by a distance Δ greater than or equal to the elongation amount of the narrow portion 11, even if the narrow portion 11 elongates, it is possible to suppress the supplementary stiffening force caused by the deformation in the higher-order buckling mode in the boundary P and its peripheral region from acting on the slit 35 and its vicinity.
[0047] Here, since there are a pair of wide portions 12 on both sides of the narrow portion 11 and the slit 35 is located at a position corresponding to the reinforcing ribs 14 in both wide portions 12 of the restraint member 30, the total elongation amount of the narrow portion 11 is L×δ. Therefore, it is sufficient to ensure that the distance Δ between the slit 35 on the left and right and the boundary P is L / 2×δ or more. However, by setting the distance Δ between both the left and right slits 35 and the boundary P to be L×δ or more, it becomes a design on the safe side. That is, in setting the distance Δ greater than or equal to the elongation amount of the narrow portion 11, whether to adopt L or L / 2 is up to the judgment of the designer.
[0048] In this way, by setting the distance Δ equal to or greater than the elongation amount of the narrow portion 11 to be the product of the longitudinal length L of the narrow portion 11 or L / 2, which is half of it, and a predetermined strain (δ), it is possible to rationally design the buckling restraint brace 100 in which the slit 35 of the restraint material 30 and its periphery are less likely to be damaged by the deformation of the higher-order buckling mode of the core material 10.
[0049] [Structure with Buckling Restraint Brace Incorporated] Next, with reference to FIGS. 7 and 8, an example of the structure of a building incorporating the buckling restraint brace 100 will be described. Here, FIG. 7 is a diagram showing a state in which the buckling restraint brace according to the embodiment is incorporated into a structure such as a wooden building. FIG. 8 is a diagram for explaining the deformation mode of the structure during a major earthquake and the additional bending moment at the buckling restraint brace joint due to the deformation of the structure. Note that the buckling restraint brace in the illustrated example may be incorporated into the structures of S-structure (S: Steel) buildings, RC-structure buildings, and SRC-structure (SRC: Steel Reinforced Concrete) buildings in addition to the structure of wooden buildings.
[0050] The structure S shown in FIG. 7 is formed by wooden columns C and beams B that constitute a wooden building or the like. Gusset plates GP made of flat steel are attached to two corner portions at diagonal positions. Fin stiffeners FS are joined to the surface of the gusset plate GP by welding so as to be orthogonal to the surface. The fin stiffeners FS are joined to the gusset plate GP such that the core L3 of the fin stiffeners FS intersects the intersection O of the column core L1 of the column C and the beam core L2 of the beam B. The buckling restraint brace 100 is also linearly arranged passing through both intersections O at diagonal positions.
[0051] The gusset plate GP and the wide portion 12 of the core material 10 are joined by high-tension bolts via a splice plate SP, and the fin stiffener FS and the reinforcing rib 14 are joined by high-tension bolts via a splice plate SP.
[0052] As shown in Fig. 8, when the structure deforms during a major earthquake, at the buckling-restrained brace joint, when the joint is regarded as rigid, the additional bending moment shown in the following formula (1) may act.
[0053]
Number
[0054] According to the buckling-restrained brace 100, the overall buckling of the buckling-restrained brace 100 can be suppressed by restraining the core material 10 with a wooden restraint body 20 including a pair of wooden restraint members 30. Therefore, the buckling-restrained brace 100 has the strength against both overall buckling and higher-order buckling of the core material 10. Therefore, it becomes possible to form a structure S with excellent seismic resistance.
[0055] [Examination of overall buckling] Next, a design method for preventing the overall buckling of the buckling-restrained brace will be described.
[0056] In the design of the buckling-restrained brace, design is performed so that the overall buckling of the buckling-restrained brace does not occur by satisfying the following formula (2).
[0057]
Number
[0058] Here, the bending moment acting at the center of the restraint member can be expressed by the following formula (3).
[0059]
Number
[0060] The condition for preventing the overall buckling of the wooden restraint body is to satisfy the following formula (4).
[0061]
Number
[0062] Equation (4) is shown in Fig. 9 as the overall buckling line of the buckling restraint brace. In Fig. 9, the upper side of the overall buckling line is the safe region, and the lower side is the dangerous region. The design axial force of the wooden restraint, the Euler load, the length of the general part of the core material, and the yield bending resistance of the wooden restraint are set so as to enter the safe region. Note that the overall buckling line of the buckling restraint brace shown in Fig. 9 is appropriate for both the overall buckling in the weak axis direction and the overall buckling in the strong axis direction of the core material.
[0063] In addition to examining the relationship between the yield bending resistance of the above-mentioned wooden restraint and the acting bending moment, it is also advisable to check that the allowable bending resistance of the short-term wooden restraint is greater than the bending moment acting at the time of core material yield (the formula is omitted).
[0064] [Examination of the embedment failure of the wooden restraint] Next, with reference to Fig. 10, the method for examining the embedment failure of the wooden restraint will be described. In the buckling restraint brace 100, in order to prevent the wooden restraint from being destroyed when the core material embeds into the wooden restraint, it is necessary to verify that the following formula (5) is satisfied.
[0065] [Equation]
[0066] Here, in addition to examining the relationship between the embedment resistance of the above-mentioned restraint material and the acting supplementary stiffness, it is also advisable to check that the allowable embedment resistance of the short-term restraint material is greater than the supplementary stiffness acting at the time of core material yield (the formula is omitted).
[0067] Note that other embodiments in which other components are combined with the configurations and the like described in the above embodiments may also be possible, and the present invention is not limited to the configurations shown here at all. In this regard, it can be changed without departing from the gist of the present invention, and can be appropriately determined according to the application form. [Description of reference numerals]
[0068] 10: Core material 10a: Wide surface 10b: Narrow surface 11: Narrow part 12: Wide part 12A: First wide part (wide part) 12B: Second wide part (wide part) 12a: Bolt hole 14: Reinforcing rib 14a: Bolt hole 20: Wooden restraint 30: Restraint material 31: Opposing surface 35: Slit 38: Shaft member (wood screw) 40: Side plate 50: Spacer 60: Steel plate 70: Buffer material 100,100A: Buckling restraint brace P: Boundary A: Plasticized region G1,G2: Gap Δ: Distance S: Structure (structural surface) C: Column B: Beam GP: Gusset plate FS: Fin stiffener SP: Splice plate
Claims
1. a steel plate-shaped core material, and a wooden restraint body formed by a pair of wooden restraint members disposed so as to face at least two wide surfaces of the core material, the core material includes a narrow-width portion where the width of the wide surface is relatively narrow on the central side in the longitudinal direction thereof, and a wide-width portion where the width of the wide surface is relatively wide on the end side in the longitudinal direction thereof, reinforcing ribs orthogonal to the wide surface are joined to the wide surfaces at the longitudinal ends of the core material, presenting a cross-sectional cross shape, among the pair of restraint members, slits that do not interfere with the reinforcing ribs are provided at positions corresponding to the reinforcing ribs, a buckling restraint brace, characterized in that the distance between the end of the slit and the boundary between the wide-width portion and the narrow-width portion is separated by an amount of elongation of the narrow-width portion or more.
2. The buckling restraint brace according to claim 1, wherein the amount of elongation is set by the product of the longitudinal length L of the narrow-width portion or L / 2 which is half thereof and a predetermined strain.
3. the wide-width portion includes a first wide-width portion at the end and a second wide-width portion that is relatively narrower in width than the first wide-width portion, the second wide-width portion is continuous with the narrow-width portion, the end of the slit is at an intermediate position of the second wide-width portion, The buckling restraint brace according to claim 1 or 2, characterized in that bolt holes through which bolts are inserted when bolted to the structure are provided in the first wide-width portion.
4. The buckling restraint brace according to claim 1 or 2, characterized in that the wooden restraint body further includes a pair of wooden side plates that connect the corresponding ends of the pair of restraint members.
Citation Information
Patent Citations
JP1974001491A