Method for designing buckling restraint brace

Abstract

To provide a design method of a buckling restraining brace which does not generate a continuous waveform of a high-order buckling mode when there is no gap between a core material and a restraining material, and does not develop the continuous waveform of the high-order buckling mode even if the waveform is generated when there is a gap between the core material and the restraining material.SOLUTION: A buckling-restrained brace 100 has a plate-shaped core material 10 made of steel, and a wooden restraining body 20 formed of a pair of wooden restraining materials 30 arranged so that opposed surfaces 31 are opposed to two wide surfaces 10a of the core material 10, and has no clearance between the wide surfaces 10a of the core material 10 and the opposed surfaces 31 of the restraining materials 30. The buckling-restrained brace is designed using the following equation (X).SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for designing a buckling-restrained brace. [Background technology]

[0002] Buckling-restrained braces, which have been designed to prevent buckling, have traditionally been used as braces to form building frames (column-beam frames, roof frames, etc.). Buckling-restrained braces come in a variety of stiffening configurations, including a steel core reinforced only with steel plates, a steel core reinforced with reinforced concrete (RC), and a steel core covered with steel and mortar.

[0003] Recently, efforts have been made to improve the fire resistance and earthquake resistance of wooden buildings (such as wooden houses, wooden warehouses, and wooden stadiums). Wooden buildings inherently have advantages such as a high degree of freedom in floor plan and design, the soothing effect of natural wood, the moisture-regulating properties of wood, and generally lower construction costs compared to steel-framed or reinforced concrete structures, depending on the building's intended use (e.g., residential). However, the improved fire resistance and earthquake resistance are one factor driving increased attention to wooden buildings, including wooden structures. When incorporating the conventional buckling restrained braces described above into the framework of such wooden buildings, wooden columns and beams are mixed with buckling restrained braces with metal or concrete stiffeners, resulting in an unbalanced appearance.

[0004] One possible solution is to cover the entire buckling restrained brace with a wooden or paper panel, making the metal or concrete stiffener invisible from the outside. However, this requires a great deal of work, which raises concerns about increased construction costs. Furthermore, conventional buckling restrained braces tend to be heavy because they make extensive use of metal, concrete, mortar, etc., and installing heavy buckling restrained braces inside the lightweight wooden beams and columns that make up a wooden building is structurally unbalanced.

[0005] Patent Document 1 proposes a buckling-restrained brace suitable for use within the framework of wooden buildings, including wooden structures. Specifically, this is a buckling-restrained brace that has a core material and a pair of restraint members arranged along both sides of the core material, where the core material is made of steel and the pair of restraint members are made of wood, and the restraint members are made of laminated lumber, with the lamina stacked parallel to the core material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4901491 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the buckling restrained brace described in Patent Document 1, the strength of the buckling restrained brace against global buckling can be improved by using a pair of restraining members made of wood.

[0008] In a buckling-restrained brace, in which a steel core is restrained by a pair of steel restraining members such as square steel pipes, a gap is provided between the wide surface of the core and the opposing surface of the restraining member to reduce friction between the steel members. However, this gap allows a compressive load to act on the core, generating a continuous waveform of a higher-order buckling mode. This continuous waveform of a higher-order buckling mode acts as a stiffening force on the restraining member beyond the gap, and the brace is designed so that the wooden restraining member can compress and resist the acting stiffening force with its rigidity.

[0009] In contrast, in a buckling-restrained brace in which a steel core is restrained by a pair of wooden restraining members as described above, the friction between the steel and the wood is small, so the design may not leave any gaps between the core and restraining members. In such a gap-free configuration, there is a possibility that continuous waveforms of higher-order buckling modes will not occur, depending on the thickness and steel type of the core, the compressive rigidity of the wooden restraining member, etc. Furthermore, even in a design without gaps between the core and restraining members, small gaps often occur due to drying shrinkage of the wooden restraining member, etc., but it can be assumed that small gaps will prevent the progression of compressive forces into the restraining member due to continuous waveforms of higher-order buckling modes.

[0010] In this way, in a buckling-restrained brace with wooden restraint members, even if a continuous wave of a higher-order buckling mode occurs, if it does not progress, no stiffening force is generated in the restraint member, or the stiffening force can be kept small, thereby maintaining the restraint member in a sound state. However, no design method has been proposed for a buckling-restrained brace that does not generate (prevents) a continuous wave of a higher-order buckling mode when no gap is provided between the core member and the wooden restraint member, or conversely, a design method for a buckling-restrained brace that does not generate (prevents) a continuous wave of a higher-order buckling mode when a gap is provided between the core member and the wooden restraint member, even if the continuous wave of a higher-order buckling mode occurs, but does not progress (prevents) a continuous wave of a higher-order buckling mode.

[0011] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a design method for a buckling-restrained brace that has wooden restraint members arranged around a steel core member, such that continuous waveforms of higher-order buckling modes are not generated when there is no gap between the core member and the restraint members, and that continuous waveforms of higher-order buckling modes are not allowed to progress even if they are generated when there is a gap between the core member and the restraint members. [Means for solving the problem]

[0012] In order to achieve the above object, one aspect of the design method for a buckling-restrained brace according to the present invention is to: A steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members arranged so that opposing surfaces face at least two wide surfaces of the core material; The buckling restraint brace, which has no gap between the wide surface of the core material and the opposing surface of the restraint material, is characterized by being designed using the following formula (X).

[0013]

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[0014] According to this aspect, by using formula (X) to design a buckling-restrained brace with no gap between the wide surface of the core material and the opposing surface of the restraining material, it is possible to design a buckling-restrained brace that does not generate continuous waveforms of higher-order buckling modes. This prevents the continuous waveforms of higher-order buckling modes from acting as a stiffening force on the wooden restraining material, thereby preventing damage to the restraining material due to embedment.

[0015] The buckling restrained brace, which is the design target of this design method, has a steel core surrounded by a wooden restraint body formed by a pair of wooden restraint members. With this configuration, even when the buckling restrained brace of this embodiment is applied to the frame of a wooden building, there is no risk of it appearing out of place with the frame components. Here, the restraint members may be made of solid wood or laminated lumber with laminated lamina.

[0016] Another aspect of the design method for a buckling-restrained brace according to the present invention is to: A steel plate-shaped core material, a wooden restraint body formed by a pair of wooden restraint members arranged so that opposing surfaces face at least two wide surfaces of the core material; The buckling restraint brace, which has a gap between the wide surface of the core material and the opposing surface of the restraint material, is characterized by being designed using the following formula (Y):

[0017]

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[0018] According to this aspect, by using formula (Y) to design a buckling-restrained brace with a gap between the wide surface of the core material and the opposing surface of the restraining material, it is possible to design a buckling-restrained brace that does not allow continuous waveforms of higher-order buckling modes to develop. This prevents the continuous waveforms of higher-order buckling modes from acting as a stiffening force on the wooden restraining material, preventing damage to the restraining material due to embedment.

[0019] Another aspect of the design method for a buckling-restrained brace according to the present invention is to: A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged to face the two wide surfaces of the core material and a pair of wooden side panels connecting the pair of restraining members; the core material has a narrow portion at a center side in a longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, a steel spacer is interposed between the end face of the narrow portion of the core material and the side plate; The buckling restraint brace, which has a gap between the end face of the narrow portion of the core material and the spacer, is characterized by being designed using the following formula (Z):

[0020]

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[0021] According to this aspect, in a buckling-restrained brace in which a steel spacer is interposed between the end face of the narrow portion of the core material and the side plate, by designing a buckling-restrained brace with a gap between the end face of the narrow portion of the core material and the spacer using equation (Z), it is possible to design a buckling-restrained brace that does not allow continuous waveforms of higher-order buckling modes to develop, even if they occur. This allows the continuous waveforms of higher-order buckling modes to act as a stiffening force on the wooden restraint body (e.g., the side plate) via the spacer, preventing damage to the wooden restraint body due to embedding. [Effects of the Invention]

[0022] As can be seen from the above explanation, the design method for a buckling-restrained brace of the present invention can provide a buckling-restrained brace design method that, for a buckling-restrained brace having wooden restraint members arranged around a steel core member, prevents continuous waveforms of higher-order buckling modes from occurring if there is no gap between the core member and the restraint members, and prevents continuous waveforms of higher-order buckling modes from progressing even if they occur if there is a gap between the core member and the restraint members. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing a core material that forms an example of a buckling-restrained brace that is the design target of a buckling-restrained brace design method according to an embodiment. [Figure 2] FIG. 1 is a perspective view of an example of a buckling-restrained brace that is the design target of a buckling-restrained brace design method according to an embodiment. [Figure 3] FIG. 3 is a view taken along the line III-III in FIG. 2, showing a longitudinal cross-sectional view of the center of an example of a buckling restrained brace. [Figure 4] FIG. 4 is a diagram corresponding to FIG. 3 and is a vertical cross-sectional view of the center of another example of a buckling-restrained brace that is the design target of the design method for a buckling-restrained brace according to an embodiment. [Figure 5] FIG. 4 is a diagram corresponding to FIG. 3 and is a vertical cross-sectional view of the center of yet another example of a buckling-restrained brace that is the design target of the method for designing a buckling-restrained brace according to an embodiment. [Figure 6] This is a model diagram of a case where there is no gap between the wide surface of the core material and the opposing surface of the restraint material. [Figure 7] This is a model diagram of a case where there is a gap between the wide surface of the core material and the opposing surface of the restraint material. [Figure 8] FIG. 10 is a model diagram showing a case where there is a gap between the narrow surface of the core material and the opposing surface of the spacer. DETAILED DESCRIPTION OF THE INVENTION

[0024] A method for designing a buckling restrained brace according to an embodiment will be described below with reference to the accompanying drawings. Note that in this specification and drawings, substantially identical components will be designated by the same reference numerals, and redundant explanations may be omitted.

[0025] [Design method for buckling-restrained braces according to the embodiment] An example of a design method for a buckling-restrained brace according to an embodiment will be described with reference to Figures 1 to 8. Here, Figure 1 is a perspective view showing a core material forming an example of a buckling-restrained brace that is the design target of the design method for a buckling-restrained brace according to an embodiment. Figure 2 is a perspective view of an example of a buckling-restrained brace that is the design target of the design method for a buckling-restrained brace according to an embodiment. Figure 3 is a view taken along the arrows III-III in Figure 2 and is a vertical cross-sectional view of the center of the example of the buckling-restrained brace. Furthermore, Figures 4 and 5 are views corresponding to Figure 3 and are vertical cross-sectional views of the center of another example of a buckling-restrained brace that is the design target of the design method for a buckling-restrained brace according to an embodiment.

[0026] As shown in Figure 1, the core material 10 that constitutes the buckling restraint brace to be designed is formed from a long, slender, plate-shaped flat steel, and has a narrow section 11 at the center of its longitudinal direction, where the width of the wide surface 10a is relatively narrow, and a wide section 12 at the end of its longitudinal direction, where the width of the wide surface 10a is relatively wide.

[0027] More specifically, the wide portion 12 has a first wide portion 12A at the end and a second wide portion 12B that is relatively narrower than the first wide portion 12A. The width is tapered from the first wide portion 12A to the second wide portion 12B. Here, the wide portion 12 does not have to have two wide portions with different widths, and may instead have only one wide portion (wide portion 12A).

[0028] A reinforcing rib 14 perpendicular to the wide surface 10a is welded to the center of the wide surface 10a from the first wide portion 12A to the second wide portion 12B, giving the wide portion 12 a cross-shaped cross section.

[0029] The core material 10 has a narrow width portion 11 at the center of its longitudinal direction and a wide width portion 12 at the end of its longitudinal direction, so that the narrow width portion 11 at the center can be made into a region that is easily plasticized (plasticization region).

[0030] In the illustrated example, the reinforcing ribs 14 are attached to the wide portion 12, which further increases the rigidity of the wide portion 12, making the narrow portion 11 more susceptible to plastic deformation. The additional bending moment acting on the core material 10 is effectively absorbed in the narrow portion 11, which is the plastic deformation region.

[0031] In addition, the wide portion 12 and the reinforcing rib 14 are each provided with bolt holes 12a, 14a for bolting via a splice plate to a gusset plate provided on a structural surface (not shown) or a fin stiffener attached to the gusset plate.

[0032] When the buckling restraint brace 100 is attached to the gusset plate so that the wide surface 10a of the core material 10 is arranged parallel to the structural face of the building, the core material 10 has reinforcing ribs 14 that are perpendicular to the wide surface 10a that is parallel to the structural face, thereby increasing the rigidity of the end of the core material 10 in the direction outside the structural face.

[0033] The core material 10 is preferably formed from a steel material with a low yield point such as SN material (rolled steel for building structures) or LYP material (extremely low yield point steel), which improves earthquake energy absorption due to yielding of the core material 10.

[0034] As shown in Figure 2, a pair of wooden restraint members 30 are arranged on either side of a pair of wide surfaces 10a of the core material 10, and a pair of wooden side panels 40 are connected to the ends of the pair of restraint members 30 to form a wooden restraint body 20, and a buckling restraint brace 100 is formed in which the core material 10 is surrounded by the wooden restraint body 20.

[0035] The restraining members 30 and the side panels 40 are connected by one or more of adhesive, nails, screws, and bolts. The wooden restraining body may also be formed by only a pair of restraining members (a configuration without side panels), in which case the pair of restraining members are connected by adhesive, nails, screws, etc.

[0036] A slit 35 is provided at the longitudinal end of the restraint material 30, and a portion of the reinforcing rib 14 joined to the end of the core material 10 is loosely fitted into the slit 35, thereby preventing interference between the restraint material 30 and the reinforcing rib 14.

[0037] The restraint member 30 is a laminated timber formed by stacking and bonding multiple laminas together. As will be explained in detail below, the cross-sectional area, cross-sectional stiffness, Young's modulus, etc. of the wooden restraint member 20 are set to prevent global buckling of the buckling restrained brace. The Young's modulus is determined by the wood material. Examples of wood materials include Japanese cypress, red pine, larch, fir, and Yezo spruce.

[0038] By surrounding the long narrow section 11 of the steel core member 10 with the wooden restraint body 20, a buckling restrained brace 100 with excellent external design can be formed. Here, although not shown, the narrow section 11 of the core member 10 may have protrusions on both wide faces 10a, and the wide faces of the restraint member 30 may have grooves at positions corresponding to the protrusions, and the protrusions may fit into both grooves, thereby preventing the core member 10 from shifting relative to the restraint member 30.

[0039] As shown in Figure 2, a gap GA of a predetermined width is provided between the slit 35 of the restraint member 30 and the reinforcing rib 14. When the structural surface to which the buckling restrained brace 100 is attached undergoes significant deformation in the strong axis direction or the weak axis direction, this gap GA absorbs the deformation of the core member 10 (and the reinforcing rib 14), preventing the reinforcing rib 14 from acting on the restraint member 30 and damaging the wooden restraint body 20.

[0040] Additionally, in the end regions of the core material 10, gaps GB are provided between the wide portions 12 and the side panels 40 and the restraining members 30. These gaps GB, like the gaps GA, absorb deformation of the core material 10 and prevent the wide portions 12 of the core material 10 from acting on the side panels 40 or the restraining members 30, thereby preventing damage to the wooden restraining body 20.

[0041] The central region of core material 10 has three types of structures depending on the type of buckling-restrained brace being designed. One of these types, buckling-restrained brace 100 shown in Figure 3, is a type in which wide surface 10a of core material 10 abuts against opposing surface 31 of restraining material 30 and is restrained.

[0042] A spacer 50 is interposed between the narrow surface 10b of the core material 10 and the side plate 40 to prevent the core material 10 from shifting toward the side plate 40. Here, the spacer 50 may be fixed to one of the restraining members 30 with nails, screws, or the like. Furthermore, although not shown, these components may be joined to each other with a plurality of bolts that pass through the pair of restraining members 30 and the spacer 50.

[0043] 3, the design is such that there is no gap between the wide surface 10a of the core material 10 and the opposing surface 31 of the restraint material 30. The design method and derivation process for a buckling restrained brace with no gap between the core material 10 and the restraint material 30 will be described in detail below.

[0044] On the other hand, the buckling restrained brace 100A shown in Figure 4 has a gap G1 between the wide surface 10a of the core material 10 and the opposing surface 31 of the restraining member 30, and is designed with this gap G1 as a given. The design method and derivation process for a buckling restrained brace with a gap between the core material 10 and the restraining member 30 will be described in detail below.

[0045] On the other hand, the buckling restrained brace 100B shown in FIG. 5 has a configuration in which there is a gap G2 between the narrow surface 10b of the narrow portion 11 of the core material 10 and the opposing surface 51 of the spacer 50 interposed between the side panel 40 that constitutes the wooden restraint body 20, and is designed with this gap G2 in mind. Note that the illustrated example shows an example in which there is a gap G2 between the opposing surface 51 of the spacer 50 and the narrow surface 10b of the core material 10. However, even if the narrow surface 10b and the opposing surface 51 abut and a similar gap G2 exists between the opposite side of the spacer 50 and the side panel 40, the spacer 50 can move between these gaps. Therefore, a structure similar to the illustrated example in which there is a gap between the narrow surface 10b of the core material 10 and the opposing surface 51 of the spacer 50 may be used. The design method and derivation process for a buckling restrained brace with a gap between the core material 10 and the spacer 50 will be described in detail below.

[0046] (Design method for buckling-restrained braces with no gap between the wide surface of the core material and the opposing surface of the restraint material) First, we will explain the design method and derivation process for a buckling-restrained brace in which there is no gap between the wide surface of the core material and the opposing surface of the restraint material, with reference to Figures 3 and 6. Here, Figure 6 is a model diagram of a case in which there is no gap between the wide surface of the core material and the opposing surface of the restraint material.

[0047] As shown in FIG. 6, the core material 10 has a buckling wavelength l n When buckling occurs at the wavelength l, which is half the buckling wavelength, n / 2 is extracted and modeled as a spring model with a spring added.

[0048] Assuming that a compressive force acts on the core material 10 and a small deformation δ occurs, the local strength B of the restraint material 30 is R can be expressed by the following equation (X1), where b is the width of the buckling restraint brace and k is the compressive stiffness of the restraint member 30.

[0049]

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[0050] On the other hand, the stiffening force B generated when the core material 10 buckles is max and the buckling mode amplitude s y When given, it can be expressed by the following equation (X2).

[0051]

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[0052] The condition under which the restraining material 30 does not suffer local failure can be expressed by the following formula (X3).

[0053]

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[0054] Here, the following formula (X4) is substituted into formula (X3).

[0055]

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[0056] However, E t is the tangent modulus of the core material 10 = 0.05E (E is Young's modulus), I is the second moment of area in the weak axis direction of the core material 10, and α is the design axial force coefficient of the restraint material 30. Substituting equation (X4) into equation (X3) gives the following equation (X5).

[0057]

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[0058] Here, the following formula (X6) is substituted into formula (X5).

[0059]

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[0060] However, F yis the yield stress of the core material 10, and t is the thickness of the core material 10. By substituting formula (X6) into formula (X5), the following formula (X7) is obtained.

[0061]

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[0062] Small deformation δ and buckling mode amplitude s y When these are equal, the required thickness of the core material 10 that constitutes the buckling restrained brace 100 can be expressed by the following equation (X8):

[0063]

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[0064] When designing a buckling-restrained brace 100 in which there is no gap between the wide surface 10a of the core material 10 and the opposing surface 31 of the restraint material 30, by using equation (X8) to design the thickness of the core material, it is possible to design a buckling-restrained brace 100 that does not generate continuous waveforms of higher-order buckling modes.

[0065] (Design method for buckling-restrained braces with a gap between the wide surface of the core and the opposing surface of the restraint material) Next, we will explain the design method and derivation process for a buckling-restrained brace with a gap between the wide surface of the core material and the opposing surface of the restraint material, with reference to Figures 4 and 7. Figure 7 is a model diagram of a case where there is a gap between the wide surface of the core material and the opposing surface of the restraint material.

[0066] In the design method for buckling-restrained braces with gaps, as shown in Fig. 6, the l n The same is true if we take / 2 and model it as a spring model with a spring added.

[0067] As shown in FIG. 7, if there is a gap S between the wide surface 10a of the core material 10 and the opposing surface 31 of the restraining material 30, and if a compressive force is applied, and a sine wave is generated and deformation Δ (where S<Δ) occurs, the local strength B of the restraining material 30 is Rcan be expressed by the following equation (Y1), where b is the width of the buckling restraint brace and k is the compressive stiffness of the restraint member 30.

[0068]

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[0069] On the other hand, the stiffening force B generated when the core material 10 buckles is max and the buckling mode amplitude s y When this is given, it can be expressed by the following equation (Y2).

[0070]

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[0071] The condition under which the stiffening force B is balanced with the local strength can be expressed by the following equation (Y3).

[0072]

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[0073] Here, the following formula (Y4) is substituted into formula (Y3).

[0074]

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[0075] However, E t is the tangent modulus of the core material 10 = 0.05E (E is Young's modulus), I is the second moment of area in the weak axis direction of the core material 10, and α is the design axial force coefficient of the restraint material 30. By substituting equation (Y4) into equation (Y3), the following equation (Y5) is obtained.

[0076]

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[0077] Here, the following formula (Y6) is substituted into formula (Y5).

[0078]

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[0079] However, F y is the yield stress of the core material 10, and t is the thickness of the core material 10. By substituting the formula (Y6) into the formula (Y5), the following formula (Y7) is obtained.

[0080]

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[0081] Deformation Δ and buckling mode amplitude s y When these are equal, the relationship between the gap S and the deformation amount Δ can be expressed by the following equation (Y8).

[0082]

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[0083] From equation (Y8), when a gap S exists, the stiffness k of the wood is reduced in accordance with the ratio between the deformation amount Δ and the size of the gap S.

[0084] Based on the following equation (Y9), by making only the first term of equation (Y9) valid, equation (Y8) can be expressed as equation (Y10).

[0085]

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[0086]

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[0087] For example, if the elastic limit of wood is given as 1 mm and the gap is given as 0.2 mm, and the wood is held in place by elastic deformation, the deformation amount Δ = 1.2 mm and the gap S = 0.2, so S / Δ = 0.167, which can be calculated as 0.75 times the rigidity k of the wood.

[0088] From equation (Y10), the required thickness t of the core material 10 can be expressed by the following equation (Y11), including the condition under which the restraining material 30 does not undergo local failure.

[0089]

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[0090] Here, an approximate formula is used to convert the formula into the following formula (Y12), where 0≦S / Δ≦0.75.

[0091]

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[0092] In this way, the formula (Y11) can be converted into a simpler formula such as the formula (Y12).

[0093] When designing a buckling-restrained brace 100A in which there is a gap between the wide surface 10a of the core material 10 and the opposing surface 31 of the restraint material 30, by designing the thickness of the core material using equation (Y11) or equation (Y12), it is possible to design a buckling-restrained brace 100A that will not allow the continuous waveforms of higher-order buckling modes to progress even if they occur.

[0094] (Design method for buckling-restrained braces with gaps between the narrow face of the core and the spacer) Next, we will explain the design method and derivation process for a buckling-restrained brace that has a gap between the end face (narrow face) of the narrow part of the core material and the spacer, with reference to Figures 5 and 8. Here, Figure 8 is a model diagram of a case where there is a gap between the narrow face of the core material and the opposing face of the spacer.

[0095] In the design method of a buckling-restrained brace with a gap between the narrow surface of the core material and the spacer, as shown in Figure 6, the buckling wavelength is half the wavelength l n The same is true if we take / 2 and model it as a spring model with a spring added.

[0096] As shown in FIG. 8, if a spacer 50 is interposed between the narrow surface 10b of the core material 10 and the side plate 40, and there is a gap S between the narrow surface 10b and the spacer 50, or a gap S between the spacer 50 and the side plate 40, and if a compressive force is applied, and a sine wave is generated and deformation Δ (where S<Δ) occurs, the local strength B of the side plate 40 is R can be expressed by the following equation (Z1), where b is the width of the buckling restraint brace and k is the compressive stiffness of the side panel 40.

[0097]

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[0098] On the other hand, the stiffening force B generated when the core material 10 buckles is max and the buckling mode amplitude s y When this is given, it can be expressed by the following equation (Z2).

[0099]

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[0100] The condition under which the stiffening force B is balanced with the local strength can be expressed by the following equation (Z3).

[0101]

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[0102] Here, the following equation (Z4) is substituted into equation (Z3).

[0103]

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[0104] However, E t is the tangent modulus of the core material 10 = 0.05E (E is Young's modulus), I is the second moment of area of ​​the core material 10, and α is the design axial force coefficient of the side panel 40. By substituting equation (Z4) into equation (Z3), the following equation (Z5) is obtained.

[0105]

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[0106] Here, the following equation (Z6) is substituted into equation (Z5).

[0107]

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[0108] However, F y is the yield stress of the core material 10, and t is the thickness of the core material 10. By substituting equation (Z6) into equation (Z5), the following equation (Z7) is obtained.

[0109]

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[0110] Deformation Δ and buckling mode amplitude s y When these are equal, the pressure-receiving area of ​​the spacer A sp (=t sp ×l sp ) can be expressed by the following equation (Z8).

[0111]

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[0112] From equation (Z8), including the condition that the side plate 40 does not undergo localized damage, the required pressure-bearing area A of the spacer is sp can be expressed by the following equation (Z9).

[0113]

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[0114] When designing a buckling-restrained brace 100B in which a steel spacer 50 is interposed between the narrow surface 10b of the core member 10 and the side plate 40, and there is a gap between the narrow surface 10b and the spacer 50, or between the spacer 50 and the side plate 40, the required pressure-bearing area A of the spacer 50 is calculated using equation (Z9). sp By designing this, it is possible to design a buckling-restrained brace that will not allow the progression of continuous waveforms of higher-order buckling modes.

[0115] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form. [Explanation of symbols]

[0116] 10: Core material 10a: Wide surface 10b:Narrow side 11: Narrow section 12: Wide section 12A: First wide section (wide section) 12B: Second wide section (wide section) 12a: Bolt hole 14: Reinforcing rib 14a: Bolt hole 20: Wooden restraint 30: Restraint material 31: Opposite surface 40: Side panel 50: Spacer 51: Opposite surface 100, 100A, 100B: Buckling restraint brace GA, GB: Gap G1, G2: Gap

Claims

1. A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged so that opposing surfaces face at least two wide surfaces of the core material; A method for designing a buckling-restrained brace, characterized in that a buckling-restrained brace in which there is no gap between the wide surface of the core material and the opposing surface of the restraint material is designed using the following formula (X): [Equation 1]

2. A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged so that opposing surfaces face at least two wide surfaces of the core material; A method for designing a buckling-restrained brace, characterized in that a buckling-restrained brace having a gap between the wide surface of the core material and the opposing surface of the restraint material is designed using the following formula (Y): [Equation 2]

3. A steel plate-shaped core material, a wooden restraining body formed by a pair of wooden restraining members arranged to face the two wide surfaces of the core material and a pair of wooden side panels connecting the pair of restraining members; the core material has a narrow portion at a center side in a longitudinal direction where the width of the wide surface is relatively narrow, and a wide portion at an end side in a longitudinal direction where the width of the wide surface is relatively wide, a steel spacer is interposed between the end face of the narrow portion of the core material and the side plate; A method for designing a buckling-restrained brace, characterized in that a buckling-restrained brace having a gap between the end face of the narrow portion of the core material and the spacer is designed using the following formula (Z): [Equation 3]

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