Buckling restraint support and its manufacturing method

Abstract

This invention provides a buckling restraint support and its manufacturing method. By studying the shape of the axial force tube of the buckling restraint support and the joint portion of the joint members disposed at both ends of the axial force tube and joined to the main body of the building structure, the energy absorption performance based on the axial force tube is improved, and it is easy to manufacture in a factory. A buckling restraint support includes: an axial force tube for bearing axial force; a reinforcing tube inserted internally to cover the outer periphery of the axial force tube; a set of end plates joined to the two ends of the axial force tube to close them; and a set of cross plates joined to the two ends of the axial force tube via the end plates and serving as a fixing portion to the main body of the building structure.

Description

Technical Field

[0001] This invention relates to a buckling restraint support for a building structure and a method for manufacturing the same. Prior Technology

[0002] Various buckling-restrained braces have been developed, which are seismic or damping braces that are inclinedly installed on the frame containing the columns and beams of the building structure to prevent buckling under compressive axial forces.

[0003] Regarding buckling restraint supports, for example, as disclosed in Patent Document 1, a double-layered steel tubular support includes: an axial force tube disposed at the center of the buckling restraint support; and a stiffening tube inserted internally to cover the outer periphery of the axial force tube. The axial force tube bears the axial force acting on the buckling restraint support, and the stiffening tube restrains the buckling deformation of the axial force tube.

[0004] When compressive forces act on the axial tube of a buckling-restrained brace during an earthquake, the axial tube undergoes buckling deformation. However, buckling is suppressed by reinforcing tubes arranged around the outer periphery of the axial tube. This increases the strength of the bracing material and reduces the cross-sectional area compared to the case without reinforcing tubes. Furthermore, during an earthquake, repeated loading of the axial tube causes it to yield and plasticize, suppressing the sharp strength drop caused by plastic deformation. Thus, under repeated loading, the energy absorption effect of the plastic deformation of the axial tube can be utilized to absorb seismic energy acting on the building structure, enabling economical and highly safe seismic design.

[0005] In buckling-restrained braces, connecting members are typically provided at both ends of the axial tube for engaging with gusset plates or similar components installed on the main body of the building structure. The connecting members of the double-layered steel tubular support disclosed in Patent Document 1 consist of connecting tubes welded to both ends of the axial tube and cross plates welded to the connecting tubes, with the cross plates serving as fixing parts to the main body of the building structure. In the double-layered steel tubular support disclosed in Patent Document 1, a notch is formed in the cross plate to improve the strength of the joint between the cross plate and the connecting tube; the two are then welded together with the connecting tube inserted into the notch. [Existing Technical Documents] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2008-223415 [Non-patent literature]

[0007] [Non-Patent Document 1] Architectural Institute of Japan, ed., "Guidelines for Vibration Reduction Design of Steel Structures, 1st Edition", Architectural Institute of Japan, November 2014, pp. 32-34 Summary of the Invention

[0008] [The problem that the invention aims to solve] In the buckling restraint brace disclosed in Patent Document 1, the axial force tube is shorter than the reinforcing tube because the connecting tube is inserted into the reinforcing tube and welded to the end of the axial force tube inside the reinforcing tube. Therefore, depending on the shape of the frame containing the columns and beams of the building structure, the length of the axial force tube cannot always be adequately ensured. In such cases, buckling restraint braces cannot be installed in the building structure, and the building structure cannot be designed as a vibration-damping structure.

[0009] Furthermore, in the buckling restraint support disclosed in Patent Document 1, a welding length corresponding to the length of the portion of the connecting tube inserted into the notch of the cross plate is required at the joint between the connecting tube and the cross plate. Therefore, the distance between the bolt hole in the cross plate, which is provided for bolting the cross plate to the main body of the building structure, and the end of the axial force tube, and the amount of the welding length become correspondingly larger, resulting in a shorter length of the axial force tube.

[0010] The axial force tube of a buckling-restrained brace absorbs energy by undergoing repeated plastic deformation under the expansion and contraction loads caused by seismic forces. As mentioned above, if the length of the axial force tube is shortened, the amount of seismic energy absorbed by the buckling-restrained brace decreases accordingly. Consequently, it becomes impossible to achieve an economical design for columns or beams in building structures that require reinforcement against seismic forces.

[0011] The present invention was made to solve the aforementioned problems and aims to provide a buckling restraint support and a method for manufacturing the same. The method improves the energy absorption performance based on the axial force tube by shaping the joint portion of the axial force tube and the joint member disposed at both ends of the axial force tube and joined to the main body of the building structure in a form that increases the length of the axial force tube relative to the total length of the buckling restraint support, and is easy to manufacture in a factory. [Methods for solving problems]

[0012] The means for solving the problem are described below. [1] A buckling restraint support has: an axial tube for bearing axial force; a reinforcing tube inserted inside the axial tube in a manner that covers the outer periphery of the axial tube; a set of end plates engaged with the two ends of the axial tube in a manner that closes the two ends of the axial tube; and a set of cross plates engaged with the two ends of the axial tube via the end plates and serving as a fixing part to the main body of the building structure. [2] As described in [1], a buckling restraint support is provided at the outer edge of the end plate, the inner surface of the axial force tube is fitted into the cut, and the axial force tube is welded to the end plate using a bevel formed by the cut of the end plate and the end face of the axial force tube. [3] As described in [1], a buckling restraint support is provided on the side of the end plate on the axial tube side, in a state of abutting against the inner surface of the axial tube, and the axial tube is welded to the end plate using a bevel formed by the side of the end plate, the backing plate and the end face of the axial tube. [4] As described in [1], a buckling restraint support is provided at the outer edge of the end plate. When the axial tube is welded to the end plate using a bevel formed by the cut and the end face of the axial tube, the cut becomes the backing of the bevel. In this state, the inner surface of the axial tube overlaps and fits into the cut. In this state, the axial tube and the end plate are welded together. [5] The buckling restraint support as described in [4], wherein a step is provided between the portion of the cut portion that forms the root gap of the bevel and the portion that engages with the axial force tube. [6] The buckling restraint support as described in [4] or [5], wherein the overlap length of the end plate and the fitting portion of the axial force tube is 5 mm to 10 mm. [7] A buckling restraint support as described in any one of [1] to [6], wherein the thickness te (mm) of the end plate is set to a value calculated using the following formula (1). Pey=2×(1+√2)×te 2×σey+π×tp×(r-tp / 2)σpy……(1) Here, Pey(N) is the yield load of the end plate, r(mm) is the outer radius of the axial tube, σey(N / mm2) is the yield stress of the end plate, π is pi, tp(mm) is the thickness of the axial tube, and σpy(N / mm2) is the yield stress of the axial tube. [8] The buckling restraint support as described in any one of [1] to [7], wherein the maximum value of the relative displacement δ (mm) between the axial force tube and the reinforcing tube, δmax (mm), satisfies the following relationship (7) to (9). δmax=εmax×L ……(7) c = a + b = h / tanθa + b ……(8) c>δmax ……(9) Here, εmax (%) is the maximum strain of the axial force tube, L (mm) is the length of the expansion and contraction range of the axial force tube relative to the reinforcing tube, h (mm) is the welding allowance between the end plate and the cross plate, a (mm) is the horizontal length of the inclined end of the cross plate relative to the welding allowance h (mm) between the end plate and the cross plate, b (mm) is the base length of the cross plate, and θa (°) is the inclination angle of the end face of the cross plate. [9] A buckling restraint support as described in any one of [1] to [7], wherein an inclined portion is provided between the base portion of the cross plate on the side that engages with the end plate and the top portion on the side that engages with the building structure, such that the width of the cross plate changes, and the maximum value δmax (mm) of the relative displacement δ (mm) between the axial force tube and the reinforcing tube satisfies the following relationship (7) to (9). Pey=2×(1+√2)×te 2×σey+π×tp×(r-tp / 2)σpy……(1) Here, Pey(N) is the yield load of the end plate, r(mm) is the outer radius of the axial tube, σey(N / mm2) is the yield stress of the end plate, π is pi, tp(mm) is the thickness of the axial tube, and σpy(N / mm2) is the yield stress of the axial tube. δmax=εmax×L ……(7) c = a + b = h / tanθa + b ……(8) c>δmax ……(9) Here, εmax (%) is the maximum strain of the axial force tube, L (mm) is the length of the expansion and contraction range of the axial force tube relative to the reinforcing tube, h (mm) is the welding allowance between the end plate and the cross plate, a (mm) is the horizontal length of the inclined end of the cross plate relative to the welding allowance h (mm) between the end plate and the cross plate, b (mm) is the base length of the cross plate, and θa (°) is the inclination angle of the end face of the cross plate.

[10] The buckling restraint support as described in any one of [1] to [9], wherein the outer diameter D1 (mm) of the axial force tube and the inner diameter D2 (mm) of the reinforcing tube satisfy the following relationship (14). 6(mm)≦D2-D1≦25(mm)……(14)

[11] The buckling restraint support as described in any one of [1] to

[10] , wherein the gap e (mm) between the axial force tube and the reinforcing tube satisfies the following relationship (15). [Number 1] …(15) In equation (15), [Number 2] …(16) [Number 3] …(17) PR(N) is the design axial force of the reinforcing tube, bMb1(N·mm) is the short-term allowable bending resistance of the reinforcing tube, E(N / mm2) is the Young's modulus of the reinforcing tube, Ib(mm4) is the moment of inertia of the cross section of the reinforcing tube, l(mm) is the buckling length of the axial force tube, e(mm) is the gap between the axial force tube and the reinforcing tube, and ν0(mm) is the initial deflection of the reinforcing tube (=l / 1000).

[12] The buckling restraint support as described in any one of [1] to

[11] , wherein the reinforcing tube is fixed to the axial force tube by a reinforcing tube fixing portion provided at a portion in the length direction of the reinforcing tube.

[13] The buckling restraint support as described in

[12] , wherein the reinforcing tube fixing part is formed by welding the reinforcing tube to the axial force tube using a welding hole provided in the reinforcing tube.

[14] The buckling restraint support as described in

[12] , wherein the reinforcing tube fixing portion is formed by welding one end of the reinforcing tube to the end plate which is engaged with one end of the axial force tube.

[15] The buckling restraint support as described in any one of [1] to

[14] , wherein a hanging member is provided on the outer peripheral surface of the reinforcing tube.

[16] A method for manufacturing a buckling restraint support, wherein a buckling restraint support as described in any one of [1] to

[15] is manufactured, wherein at least one of a set of end plates is formed in a planar shape having a cross-sectional shape smaller than that of the inner periphery of the reinforcing tube, the axial force tube is inserted into the interior of the reinforcing tube from one side joined with the end plate having a planar shape smaller than that of the inner periphery of the reinforcing tube, and then the cross plate is joined to the end plate having a planar shape smaller than that of the inner periphery of the reinforcing tube.

[17] A method for manufacturing a buckling restraint support, wherein a buckling restraint support as described in any one of [4] to [6] is manufactured, wherein in the manufacturing method, when the axial force tube is welded to the end plate using a bevel formed by the cut portion and the end face of the axial force tube, the cut portion serves as a backing for the bevel, and in this state, the inner surface of the axial force tube is overlapped and fitted into the cut portion, and in this state, the axial force tube is welded to the end plate. [The effects of the invention]

[0013] By means of the buckling restraint support and its manufacturing method of the present invention, the cross plate, which serves as a fixing part to the main body of the building structure, is joined to both ends of the axial force tube via an end plate that is joined in a manner that closes both ends of the axial force tube. Therefore, the distance between the bolt holes provided in the cross plate for bolting the cross plate to the main body of the building structure and the ends of the axial force tube can be reduced.

[0014] As a result, the length of the axial force tube relative to the total length of the buckling-restrained brace can be increased. This leads to a greater absorption of seismic energy from the application of seismic forces to the axial force tube of the buckling-restrained brace and the subsequent plastic deformation of the axial force tube. Therefore, the building structure can be designed as a highly damping structure, improving the overall economic efficiency of the building structure. Simple Explanation of the Diagram

[0015] Figure 1(a) is a side view of a buckling restraint support according to an embodiment of the present invention. Figures 1(b) and 1(c) are cross-sectional views along line IB-IB and line IC-IC of the buckling restraint support shown in Figure 1(a), respectively. Figure 2 is an enlarged view of the main part of the buckling restraint support shown in Figure 1(a). Figure 3 is an enlarged view of the main part of the buckling restraint support shown in Figure 1(a). Figure 4 is a cross-sectional view showing an example of the joint configuration of the axial force tube and the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 5 is a cross-sectional view showing another example of the engagement configuration of the axial force tube and the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 6 is a cross-sectional view showing another example of the joint configuration of the axial force tube and the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 7 is a cross-sectional view showing another example of the joint configuration of the axial force tube and the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 8 is a cross-sectional view showing another example of the joint configuration of the axial force tube and the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 9(a) and Figure 9(b) are a cross-sectional view and a side view of an example of the reinforcing tube fixing part of a buckling restraint support according to an embodiment of the present invention. Figure 10 is a cross-sectional view of a buckling restraint support, showing another example of the reinforcing tube fixing portion of a buckling restraint support according to an embodiment of the present invention. Figure 11 is a side view showing an example of a buckling restraint support hanging member according to an embodiment of the present invention. Figure 12 is a perspective view schematically showing the out-of-plane deformation generated in the end plate of a buckling restraint support according to an embodiment of the present invention. Figures 13(a) and 13(b) are side views of the test specimen used in a force test to confirm the amount of out-of-plane deformation generated in the end plate of a buckling restraint support of an embodiment of the present invention. Figure 14 is a graph showing the results of a force test used to confirm the amount of out-of-plane deformation generated in the end plate of a buckling restraint support according to an embodiment of the present invention. Figure 15 is a graph showing an example of the strain distribution generated at the end of the axial force tube of a buckling restraint support according to an embodiment of the present invention. Figure 16 is a graph showing an example of the strain distribution generated at the end of the vane of a buckling restraint support according to an embodiment of the present invention. Figure 17 is a side view showing the length of the expansion range of the axial force tube of the buckling restraint support member of an embodiment of the present invention, which generates relative displacement between itself and the reinforcing tube by bearing a load and expanding and contracting. Figure 18 is a side view showing the length of the expansion range of the axial force tube of the buckling restraint support member of an embodiment of the present invention, which generates relative displacement between itself and the reinforcing tube by bearing a load and expanding and contracting. Figure 19 is a graph illustrating an example of the stress-strain relationship of the axial force tube of a buckling restraint support according to an embodiment of the present invention. Figure 20 is a graph showing another example of the stress-strain relationship of the axial force tube of a buckling restraint support according to an embodiment of the present invention. Figures 21(a) and 21(b) are diagrams illustrating an example of the relative displacement between the axial force tube and the reinforcing tube of a buckling restraint support in an embodiment of the present invention. Figure 22 is a diagram showing the relationship between the outer diameter of the axial force tube and the inner diameter of the reinforcing tube of a buckling restraint support according to an embodiment of the present invention. Figure 23 is a flowchart illustrating an example of a method for manufacturing a buckling restraint support according to an embodiment of the present invention. Implementation

[0016] Hereinafter, with reference to the drawings, embodiments of the buckling restraint support and its manufacturing method of the present invention will be described.

[0017] [Buckling-restrained support] Figure 1(a) shows a side view of a buckling restraint support 1 according to an embodiment of the present invention. In addition, Figure 1(b) and Figure 1(c) show cross-sectional views of the buckling restraint support 1 shown in Figure 1(a) along line IB-IB and line IC-IC, respectively.

[0018] As shown in Figures 1(a) to 1(c), the buckling restraint support 1 includes: an axial force tube 11, a reinforcing tube 12, a set of end plates 13, and a set of cross plates 14. The axial force tube 11 is constructed of a cylindrical steel tube and bears the axial force input to the buckling restraint support 1. The reinforcing tube 12 is also constructed of a cylindrical steel tube, and is configured to cover the outer periphery of the axial force tube 11 by inserting the axial force tube 11 inside the reinforcing tube 12. The end plates 13 are constructed of circular steel plates and are welded to both ends of the axial force tube 11 in a manner that closes both ends. The cross plates 14 are constructed by combining steel plates in a cross-shaped cross section, and are welded to both ends of the axial force tube 11 via the end plates 13, serving as a fixing part to the main body of the building structure (not shown). Specifically, in the building structure, a frame-side cross plate 21 is provided at a position opposite to the cross plates 14 of the buckling restraint support 1. Furthermore, the buckling restraint support 1 is fixed to the building structure by frictionally joining the cross plate 14 of the buckling restraint support 1 to the frame-side cross plate 21 of the building structure using splicing plate 22 and high tensile bolts. The reinforcing tube 12 is fixed to the axial force tube 11 by a reinforcing tube fixing part (described later) provided in a part along the length of the reinforcing tube 12.

[0019] Figures 2 and 3 show enlarged views of the main part of the buckling restraint support 1 shown in Figure 1(a).

[0020] As shown in Figures 2 and 3, the end plate 13, which is welded to both ends of the axial force tube 11, is inserted into the interior of the reinforcing tube 12 together with the axial force tube 11. The outer diameter of the end plate 13 is set below the outer diameter of the axial force tube 11. A notch 13a is provided on the outer edge of the end plate 13 by machining, and the inner surface of the axial force tube 11 is fitted into the notch 13a. In this state, a bevel is formed by the notch 13a of the end plate 13 and the end face of the axial force tube 11, and the axial force tube 11 is welded to the end plate 13 using this bevel. The surface of the weld metal W in the welded joint between the axial force tube 11 and the end plate 13 does not contact the inner surface of the reinforcing tube 12.

[0021] The portion of the cutout 13a of the end plate 13 facing the end face of the axial tube 11 is preferably an inclined surface with an angle θ1 relative to the radial direction of the end plate 13. This inclined surface allows the weld joint between the axial tube 11 and the end plate 13 to have a bevel angle. The flat portion of the cutout 13a of the end plate 13, excluding the inclined surface, serves as a backing for the weld metal W. Ideally, the overlap length L1 between the flat portion of the cutout 13a of the end plate 13 and the fitting portion of the axial tube 11 is 5 mm to 10 mm. The length L2 of the flat portion of the cutout 13a of the end plate 13, excluding the fitting portion with the axial tube 11, forms the root gap of the weld joint between the axial tube 11 and the end plate 13.

[0022] Furthermore, as shown in Figures 2 and 3, the width of the cross plate 14 differs between the base 14a on the side that engages with the end plate 13 and the top 14b on the side that engages with the frame-side cross plate 21 of the building structure, with the latter being set larger.

[0023] The width of the base 14a on the side of the cross plate 14 that engages with the end plate 13 is preferably set to be at least 20 mm smaller than the diameter of the end plate 13. This ensures a welding allowance h of at least 10 mm for circumferential welding between the outer edge of the end plate 13 and the base 14a of the cross plate 14. Furthermore, while the width of the base 14a of the cross plate 14 is constant, the length L3 of the base 14a in the longitudinal direction of the buckling restraint support 1 is set to a sufficient size to prevent the cross plate 14 from contacting the reinforcing tube 12 when the axial force tube 11 shrinks under compressive force.

[0024] The width of the top portion 14b of the cross plate 14, which engages with the frame-side cross plate 21 of the building structure, is fixed and set to be the same as the width of the frame-side cross plate 21 of the building structure. Therefore, at the top portion 14b of the cross plate 14, the cross plate 14 of the buckling restraint support 1 can be frictionally engaged with the frame-side cross plate 21 of the building structure using the splicing plate 22 and high-tensile bolts.

[0025] Furthermore, an inclined portion 14c is provided between the base 14a and the top portion 14b of the cross plate 14 to change the width of the cross plate 14. The inclination angle θa of the side of the cross plate 14 at the inclined portion 14c is preferably set to 45° or less. If so, the axial force can be smoothly transmitted between the axial force tube 11 of the buckling restraint support 1 and the building structure.

[0026] Figures 4 to 7 show cross-sectional views of another example of the joint configuration of the axial force tube 11 of the buckling restraint support 1 and the end plate 13.

[0027] In the example shown in Figure 4, an inclination angle θ2 is also provided on the end face of the axial force tube 11, which faces the inclined surface of the cut portion 13a of the end plate 13. Furthermore, by using the inclined surface of the cut portion 13a of the end plate 13 and the end face of the axial force tube 11, the bevel of the welded joint between the axial force tube 11 and the end plate 13 has a bevel angle. In this case, it is ideal to set the inclination angle θ1 of the inclined surface of the cut portion 13a of the end plate 13 to 10°~20°, the inclination angle θ2 of the end face of the axial force tube 11 to 30°~40°, and the root gap L2 of the bevel of the welded joint between the axial force tube 11 and the end plate 13 to 3 mm~7 mm.

[0028] In the example shown in Figure 5, no inclination angle is provided on the end face of the axial force tube 11 facing the inclined surface of the cut portion 13a of the end plate 13. In this case, it is ideal to set the inclination angle θ1 of the inclined surface of the cut portion 13a of the end plate 13 to 30°~40°, and the root gap L2 of the bevel of the welded joint between the axial force tube 11 and the end plate 13 to 3 mm~7 mm.

[0029] The example shown in Figure 6 is an example of the example shown in Figure 4, in which a step difference of less than 1 mm is provided between the portion of the flat portion of the cut 13a of the end plate 13 that forms the root gap L2 of the bevel for the weld joint between the axial tube 11 and the end plate 13, and the fitting portion of the axial tube 11. Similarly, the example shown in Figure 7 is an example of the example shown in Figure 5, in which a step difference of less than 1 mm is provided between the portion of the flat portion of the cut 13a of the end plate 13 that forms the root gap L2 of the bevel for the weld joint between the axial tube 11 and the end plate 13, and the fitting portion of the axial tube 11. Thus, by providing a step difference in the flat portion of the cut 13a of the end plate 13, the root gap L2 of the bevel for the weld joint between the axial tube 11 and the end plate 13 can be easily adjusted to a predetermined length. Furthermore, the reduced gap between the inner surface of the axial force tube 11 and the flat portion of the cutout 13a of the end plate 13 makes the welding connection between the axial force tube 11 and the end plate 13 more reliable. In particular, when the actual inner diameter of the axial force tube 11 is smaller than a specified value, the gap between the inner surface of the axial force tube 11 and the flat portion of the cutout 13a of the end plate 13 can be adjusted by the aforementioned step difference, so that the inner surface of the axial force tube 11 can be smoothly fitted into the cutout 13a of the end plate 13.

[0030] Figure 8 shows a cross-sectional view of another example of the joint configuration of the axial force tube 11 of the buckling restraint support 1 and the end plate 13.

[0031] In the example shown in Figure 8, no notch 13a is provided in the end plate 13. Furthermore, a backing plate 13b is provided on the side of the end plate 13 on the side of the axial tube 11, in contact with the inner surface of the axial tube 11. The axial tube 11 is welded to the end plate 13 using a bevel formed by the side of the end plate 13, the backing plate 13b, and the end face of the axial tube 11. An inclination angle θ2 is provided on the end face of the axial tube 11 facing the side of the end plate 13. Moreover, the bevel formed by the side of the end plate 13 and the end face of the axial tube 11 provides a bevel angle for the welded joint between the axial tube 11 and the end plate 13.

[0032] In the structure shown in Figure 8, a backing plate 13b is required, but machining for the notch 13a in the end plate 13 is not necessary. When the yield strength of the buckling restraint support 1 is large and the outer diameter of the end plate 13 is large, the cost of machining for the notch 13a in the end plate 13 increases. However, by adopting the structure shown in Figure 8, this machining is not required, thus improving economy.

[0033] Figures 9(a) and 9(b) show a cross-sectional view and a side view of the peripheral portion of the reinforcing tube fixing part 15 of the buckling restraint support 1, respectively.

[0034] In the examples shown in Figures 9(a) and 9(b), the reinforcing tube 12 is fixed to the axial force tube 11 by a reinforcing tube fixing part provided at a portion along the length of the reinforcing tube 12. The reinforcing tube fixing part is constructed by welding the reinforcing tube 12 to the axial force tube 11 using a welding hole 12a provided in the reinforcing tube 12 and by using a plug weld 15.

[0035] Specifically, as shown in Figures 9(a) and 9(b), a fixing plate 11a is welded to the center of the axial force tube 11 along its length. Additionally, a welding hole 12a is provided at the center of the reinforcing tube 12 along its length. The diameter of this welding hole 12a is ideally set to 20 mm to 40 mm. Furthermore, the fixing plate 11a of the axial force tube 11 and the welding hole 12a of the reinforcing tube 12 are fixed together by using a plug weld 15, thereby forming a reinforcing tube fixing part.

[0036] Ideally, the reinforcing tube fixing part is provided at 2 to 3 locations along the circumferential direction at the center of the axial force tube 11 along its length. This allows the axial force tube 11 and the reinforcing tube 12 to be fixed using plug welds 15, ensuring that the gap between the outer surface of the axial force tube 11 and the inner surface of the reinforcing tube 12 is uniform in the circumferential direction, reliably enhancing the stiffening effect of the reinforcing tube 12 on the axial force tube 11. Furthermore, by fixing the positions of the axial force tube 11 and the reinforcing tube 12, even when the buckling restraint support is installed at an angle, it prevents the reinforcing tube 12 from shifting downwards and its end from contacting the end face of the cross plate 14, thus preventing damage to the coating. Moreover, by using plug welds for partial joining, the gap between the outer surface of the axial force tube 11 and the inner surface of the reinforcing tube 12 is connected at the reinforcing tube fixing part, facilitating the removal of rainwater or dust that may intrude into the gap between the axial force tube 11 and the reinforcing tube 12.

[0037] Figure 10 shows a cross-sectional view of another example of the reinforcing tube fixing part of the buckling restraint support 1.

[0038] In the example shown in Figure 10, the reinforcing tube fixing part is formed by welding one end of the reinforcing tube 12 to the end plate 13 which is joined to one end of the axial force tube 11.

[0039] Specifically, as shown in Figure 10, a reinforcing tube weld portion 13c is provided on the outer periphery of the end plate 13 by machining, and the inner surface of the reinforcing tube 12 is in contact with the outer periphery of the reinforcing tube weld portion 13c. A portion of the outer periphery of the reinforcing tube weld portion 13c protrudes further outward from the end face of the reinforcing tube 12 along its axial direction, and the end face of the reinforcing tube 12 is fixed to the reinforcing tube weld portion 13c of the end plate 13 by a fillet weld 16. In addition, a notch portion 13a is provided on the outer edge of the end plate 13 by machining, and the inner surface of the axial force tube 11 is fitted into the notch portion 13a. In this state, a bevel is formed by the notch portion 13a of the end plate 13 and the end face of the axial force tube 11, and the axial force tube 11 is welded to the end plate 13 using the bevel and the welding metal W.

[0040] Thus, by fixing the axial force tube 11 and the reinforcing tube 12 via the end plate 13 and the fillet weld 16, the gap between the outer surface of the axial force tube 11 and the inner surface of the reinforcing tube 12 is made uniform in the circumferential direction, and the reinforcing effect of the reinforcing tube 12 on the axial force tube 11 can be reliably exerted. In addition, by fixing the positions of the axial force tube 11 and the reinforcing tube 12, when the buckling restraint support is installed at an angle, it is possible to prevent the reinforcing tube 12 from shifting downward and its end from contacting the end face of the cross plate 14, thus preventing damage to the paint. Moreover, when the buckling restraint support 1 is installed at an angle in a building structure, by arranging the buckling restraint support 1 with the reinforcing tube fixing part 16 as the upper side of the buckling restraint support 1, it is possible to prevent rainwater or dust from penetrating into the interior of the buckling restraint support 1. In particular, when the buckling restraint support 1 is installed outdoors and is affected by wind and rain, by setting the reinforcing tube fixing part as shown in FIG. 10, it is effective in protecting the buckling restraint support 1.

[0041] Figure 11 shows a side view of an example in which a buckling restraint support 1 is provided with a hanger 17.

[0042] As shown in Figure 11, a hanger 17 is provided on the outer peripheral surface of the reinforcing tube 12 of the buckling restraint support 1. The hanger 17 has a hole for passing through a shackle or similar device for suspension.

[0043] If so, the suspension operation of the buckling restraint brace 1 using a crane or the like becomes easier when installing it in the frame of a building structure. This reduces the steps involved in installing the buckling restraint brace 1 in a building structure and improves safety.

[0044] Ideally, two suspension members 17 are arranged at equal intervals on both sides from the center of the buckling restraint support 1 along its length. This improves the stability of the buckling restraint support 1 during suspension and further enhances its safety.

[0045] [Thickness of the end plate] Figure 12 schematically illustrates the out-of-plane deformation that occurs in the end plate 13 of the buckling restraint support 1 of the present invention.

[0046] In this embodiment, one side of the end plate 13 of the buckling-restrained support 1 engages with the cross-shaped section of the vane plate 14, and the other side engages with the circular section of the axial force tube 11. Therefore, as shown in FIG12, when a tensile load is applied to the buckling-restrained support 1 due to seismic forces, local tensile forces act from the vane plate 14 onto the end plate 13, resulting in uneven out-of-plane deformation. At this time, as indicated by the ○ mark in FIG12, bending occurs at the joint between the end plate 13 and the vane plate 14, generating large stress. In order to prevent damage to the end plate 13, it is necessary to set the plate thickness of the end plate 13.

[0047] In the buckling restraint support 1, the collapse mechanism of the end plate 13 consists of the bending yielding of the yield line portion of the end plate 13 and the axial yielding of the end of the axial force tube 11. If the yield line theory based on this collapse mechanism is used to guide the evaluation formula of the out-of-plane yield endurance of the end plate 13, it is as shown in the following formula (1). Pey=2×(1+√2)×te 2×σey+π×tp×(r-tp / 2)σpy……(1) Here, Pey(N) is the yield load of end plate 13, r(mm) is the outer radius of axial tube 11, σey(N / mm2) is the yield stress of end plate 13, π is pi, te(mm) is the plate thickness of end plate 13, tp(mm) is the plate thickness of axial tube 11, and σpy(N / mm2) is the yield stress of axial tube 11.

[0048] Next, a force test will be conducted to confirm the out-of-plane deformation generated in the end plate 13 of the buckling restraint support 1 of the present invention, as well as the strain generated at the end of the axial force tube 11 and the end of the cross plate 14 that are engaged with the end plate 13. Therefore, this will be explained below.

[0049] Figures 13(a) and 13(b) show side views of the test specimen used in this force test.

[0050] As shown in Figures 13(a) and 13(b), the test body used in this force test is configured to include an end plate 13 in the buckling restraint support 1, and a joint portion of an axial force tube 11 and a cross plate 14 that are connected to its two sides.

[0051] In the test specimen used in this stress test, the end plate 13 is made of SN490B as specified in Japanese Industrial Standards (JIS) G3136 (Rolled Steel for Building Structures), and its thickness te is set to 12 mm. The axial force tube 11 is made of STK400 as specified in Japanese Industrial Standard JIS G3444 (Carbon Steel Tubes for General Structures), with an outer diameter Φ of 216.3 mm and a thickness tp of 5.8 mm. The vane plate 14 is made of SN490B, with a width of 210 mm × 210 mm and a thickness of 16 mm.

[0052] Then, a tensile load was applied to the test specimen, and a force-applied test was conducted under conditions in which the tensile force was gradually increased. The out-of-plane deformation (mm) generated in the end plate 13 of the test specimen, and the strain (%) generated at the end of the axial force tube 11 and the end of the cross plate 14 connected to the end plate 13 were confirmed. In addition, a numerical analysis based on the finite element method was performed on the analytical model simulating the test specimen under the same force-applied conditions.

[0053] Figure 14 shows the relationship between the tensile load F (kN) obtained through the force test and numerical analysis and the out-of-plane deformation (mm) generated in the end plate 13 of the test specimen. In Figure 14, the thick solid line represents the experimental value, the thin solid line represents the analytical value, the thick dashed line is the line obtained by approximating the curve of the experimental value with bilinearity, and the thin dashed line is the line obtained by approximating the curve of the analytical value with bilinearity. Regarding the yield load Py of the end plate 13, for each of the lines (thick dashed line and thin dashed line) obtained by approximating the curve of the experimental value or the analytical value with bilinearity, it is taken as the value of the tensile load F (kN) at the intersection of the initial gradient and the second gradient. The ● and ○ marks in Figure 14 are obtained by plotting the points on the curve of the experimental value (thick solid line) or the curve of the analytical value (thin solid line) where the tensile load F (kN) is Py, 2 / 3Py, and 1 / 3Py, respectively.

[0054] As shown in Figure 14, the initial stiffness of the end plate 13 shows a good correspondence between the experimental and analytical values. However, the yield load Py of the end plate 13 is about 14% smaller than the experimental value in the case of the analytical value.

[0055] Figure 15 shows the strain (%) distribution at the end of the axial force tube 11 of the test specimen when the tensile load F (kN) is Py, 2 / 3Py, and 1 / 3Py, respectively, obtained by the aforementioned force test and numerical analysis. The horizontal axis of Figure 15 represents the 0° and 90° positions of the joint between the end plate 13 and the cross plate 14, and the positions in between, about 1 / 4 of the cross section of the axial force tube 11.

[0056] As shown in Figure 15, it is known that when the tensile load F (kN) is Py, near 0° and 90° of the joint between the end plate 13 and the cross plate 14, the axial force tube 11 experiences large strain, the end plate 13 undergoes out-of-plane deformation, and the axial force tube 11 yields. Furthermore, it is known that when the tensile load F (kN) is 2 / 3Py and 1 / 3Py, the strain of the axial force tube 11 is small, the end plate 13 exhibits sufficient rigidity, and the stress generated by the axial force tube 11 is dispersed.

[0057] Figure 16 shows the strain (%) distribution at the end of the vane 14 of the test specimen under tensile loads F (kN) of Py, 2 / 3Py, and 1 / 3Py, obtained through the aforementioned force test and numerical analysis. Figure 16 also shows the axial strain distribution of the vane 14 at a position 20 mm away from the surface of the end plate 13. The horizontal axis of Figure 16 represents the cross-section of the vane 14 as 0 and the top of the vane 14 in the width direction as -1 or 1.

[0058] As shown in Figure 16, the strain generated at the end of the vane 14 increases towards the tip in the width direction of the vane 14. When the tensile load F (kN) is Py, the analyzed value of the strain generated at the end of the vane 14 is larger than the experimental value. This is similar to the situation shown in Figure 14 where the analyzed value of the out-of-plane deformation of the end plate 13, compared to the experimental value, indicates a further advancement in the yielding of the end plate 13. Thus, the analyzed value of the strain generated at the end of the vane 14, compared to the experimental value, indicates an early yielding of the end plate 13. However, within the elastic range, the initial stiffness and strain distribution of the end plate 13 show a good correspondence between the experimental and analyzed values, indicating safety under the analyzed value conditions. Therefore, the end plate 13's endurance can be evaluated using the analyzed values.

[0059] Table 1 shows the experimental value, analytical value, and calculated value of the yield load of the end plate 13 obtained by equation (1).

[0060] [Table 1] Experimental value (kN) Analytical value (kN) Calculated value (kN) Experimental value / Calculated value Analyzed value / Calculated value 988 865 1040 0.95 0.83

[0061] The experimental value of the yield load of the end plate 13 is 0.95 times the calculated value obtained from equation (1), and the experimental value and the calculated value show a good correspondence. On the other hand, since the analytical value of the yield load of the end plate 13 is less than the experimental value, the analytical value is 0.83 times the calculated value obtained from equation (1).

[0062] Regarding the buckling restraint support 1, it is appropriate to design the end plate 13 to be within the elastic range when the axial force tube 11 reaches its yield strength. Therefore, the short-term allowable tensile strength Pa (N) of the end plate 13, obtained by equation (1) based on the yield line theory, is calculated by multiplying the calculated value by a discount factor of 2 / 3 (=1 / 1.5) as shown in equation (2) below. Moreover, it is safe to design the end plate 13 so that its short-term allowable tensile strength Pa (N) is greater than the yield strength Ppy (N) of the axial force tube 11, as shown in equation (3) below. If this discount factor is used, a sufficiently safe result can also be obtained for the yield load Py of the end plate 13 obtained by the numerical analysis. Pa = Pey / 1.5 ……(2) Pa≧Ppy ……(3) The required plate thickness te (mm) of the end plate 13 is calculated as follows: First, the yield strength Ppy (N) of the axial force tube 11 is obtained, and the short-term allowable tensile strength Pa (N) of the end plate 13 is set by the above formula (3). Then, the yield load Pey (N) of the end plate 13 is calculated by the above formula (2), and the plate thickness te (mm) of the end plate 13 is calculated by the above formula (1).

[0063] Table 2 shows an example of calculating the required plate thickness te (mm) of the end plate 13 using equations (1) to (3).

[0064] [Table 2] No. Axial tube end plate Calculation process Material σ.py (N / mm2) Ppy (kN) d (mm) r=d / 2 (mm) tp (m) Material σey (N / mm2) Pa=Ppy (N / mm2) (3) Pey=1.5 Pa (kN) (2) te (mm) (1) 1 JFE-LY225S 205 1010 165.2 82.6 10.1 SN490C 295 1010 1515 26.6 2 JFE-LY225S 205 2010 241.8 120.9 13.7 SN490C 295 2010 3015 37.6 3 JFE-LY225S 205 3000 273.1 136.55 18.3 SN490C 295 3000 4500 45.9

[0065] In the calculation example shown in Table 2, the material of the axial force tube 11 is JFE-LY225S low yield point steel tube for building structures manufactured by JFE Steel Co., Ltd. Furthermore, the material of the end plate 13 is SN490C as specified in Japanese Industrial Standard JIS G3136 (Rolled Steel for Building Structures).

[0066] As shown in Table 2, the greater the yield strength Ppy (N) of the axial force tube 11, the greater the required plate thickness te (mm) of the end plate 13.

[0067] By setting the thickness t of the end plate 13 shown in Figures 3-7 to be greater than or equal to the required thickness te (mm) of the end plate 13 calculated using the aforementioned method, the end plate 13 can be kept within the elastic range when the axial force tube 11 reaches its yield strength. This suppresses out-of-plane deformation of the end plate 13, reduces stress concentration at the joint between the end plate 13 and the axial force tube 11 and the cross plate 14, and ensures the safety of the joint.

[0068] Figures 17 and 18 are side views showing the length L (mm) of the range of relative displacement between the axial force tube 11 of the buckling restraint support 1 and the reinforcing tube 12 caused by the axial force tube 11 bearing load and expanding and contracting. Figure 17 shows an example in which the reinforcing tube fixing part for fixing the reinforcing tube 12 to the axial force tube 11 is provided at the center of the axial force tube 11 along its length, as shown in Figures 9(a) and 9(b). Figure 18 shows an example in which the reinforcing tube fixing part for fixing the reinforcing tube 12 to the axial force tube 11 is provided at one end of the axial force tube 11, as shown in Figure 10.

[0069] When an axial load is applied to the axial force tube 11, the axial force tube 11 generates axial strain and expands / contracts. In contrast, the axial load does not act on the reinforcing tube 12, therefore the reinforcing tube 12 does not expand / contract. At this time, the relative displacement between the axial force tube 11 and the reinforcing tube 12 at the reinforcing tube fixing part is zero. Furthermore, at the end face of the axial force tube 11 located at a distance L (mm) from the reinforcing tube fixing part relative to the reinforcing tube 12, a relative displacement δ (mm) proportional to the length L (mm) of the expansion / contraction range is generated.

[0070] If the axial strain generated in the axial force tube 11 when it is subjected to axial load is ε, then the relative displacement δ (mm) between the end face of the axial force tube 11 and the reinforcing tube 12 is expressed as in equation (4) below. δ=ε×L ……(4)

[0071] Figures 19 and 20 show examples of historical stress-strain curves of the axial force tube 11 obtained from force tests in which alternating positive and negative axial loads were applied to the buckling restraint support 1. The horizontal axis of Figures 19 and 20 represents the strain degree (%) of the axial force tube 11, and the vertical axis represents the stress degree (N / mm2) of the axial force tube 11.

[0072] Figure 19 shows an example of an axial force tube 11 using JFE-LY225S low yield point steel tubes for building structures manufactured by JFE Steel Corporation. In the example shown in Figure 19, alternating positive and negative repetitive loads acting in the axial direction of the buckling restraint support 1 are controlled based on the strain generated in the axial force tube 11, and the force is repeatedly applied at a strain of ±2.0%. As a result, the stress-strain relationship of the axial force tube 11 shows a stable historical curve, and the axial force tube 11 exhibits high energy absorption capacity within the strain range of ±2.0%.

[0073] Figure 20 shows an example of an axial force tube 11 using STKN400B as specified in Japanese Industrial Standard JIS G3444 (Carbon Steel Tubes for General Structures). In the example shown in Figure 20, the alternating positive and negative cyclic loads acting in the axial direction of the buckling restraint support 1 are controlled based on the strain generated in the axial force tube 11, with each cycle applying a strain of ±0.25%, ±0.5%, ±0.75%, ±1.0%, ±1.25%, and ±1.5%. As a result, the stress-strain relationship of the axial force tube 11 shows a stable historical curve, and the axial force tube 11 exhibits high energy absorption capacity within the strain range of ±1.5%.

[0074] Based on these results, when the buckling restraint brace 1 is used as a damping member that can absorb energy during an earthquake, the maximum strain εmax (%) of the axial force tube 11 of the buckling restraint brace 1 is preferably specified as in equation (5) or (6) below. 1) When the axial force tube 11 uses JFE-LY225S or JFE-LY100S low yield point steel tubes for building structures manufactured by JFE Steel Corporation. εmax = ±2.0% ……(5) 2) When the axial force tube 11 uses STKN400B or STKN490B as specified in Japanese Industrial Standard JIS G3475 (Carbon steel tubes for building structures) or STK400 or STK490 as specified in Japanese Industrial Standard JIS G3444 (Carbon steel tubes for general structures) εmax = ±1.5% ……(6) Furthermore, when using the buckling restraint support 1 as a seismic support within the elastic range of the axial force tube 11, the maximum strain εmax (%) of the axial force tube 11 of the buckling restraint support 1 is preferably set to ±0.2% or less. Moreover, according to the above equation (4), the maximum value of the relative displacement between the end face of the axial force tube 11 and the reinforcing tube 12 is as shown in the following equation (7). δmax=εmax×L ……(7)

[0075] Figures 21(a) and 21(b) show an example of the relative displacement δ (mm) of the axial force tube 11 and the reinforcing tube 12 of the buckling restraint support 1 in an embodiment of the present invention.

[0076] Figure 21(a) shows the state near the joint of the end plate 13 and the axial force tube 11 and the cross plate 14 connected to it on both sides, when no axial load is applied to the axial force tube 11. At this time, the relationship of the following equation (8) holds. c = a + b = h / tanθa + b ……(8) Here, h (mm) is the welding allowance between the end plate 13 and the cross plate 14, a (mm) is the horizontal length of the inclined end of the cross plate 14 relative to the welding allowance h (mm) between the end plate 13 and the cross plate 14, b (mm) is the base length of the cross plate 14, and θa (°) is the inclination angle of the end face of the cross plate 14.

[0077] Figure 21(b) shows a state where an axial compressive load acts on the axial force tube 11, causing the axial force tube 11 to shrink and the outer side of the end plate 13 to shift inward toward the reinforcing tube 12. The maximum value δmax(mm) of the relative displacement δ(mm) between the axial force tube 11 and the reinforcing tube 12 at this time is as shown in equation (7). If the maximum value δmax(mm) of the relative displacement δ(mm) is within the range that satisfies equation (9) below, it can prevent the reinforcing tube 12 from contacting the cross plate 14 and being damaged. c>δmax ……(9)

[0078] The welding allowance h (mm) between the end plate 13 and the cross plate 14 is preferably set in a manner that satisfies the relationship in equation (10) below. If so, the welding cross section between the end plate 13 and the cross plate 14 can be sufficiently ensured, and the joint strength between the end plate 13 and the cross plate 14 can be reliable. h≧10(mm) ……(10)

[0079] Furthermore, as described above, an inclined portion 14c is provided between the base 14a and the top portion 14b of the cross plate 14 to change the width of the cross plate 14. The inclination angle θa (°) of the side of the cross plate 14 at the inclined portion 14c is preferably set in a manner that satisfies the relationship of the following equation (11). If so, the axial force of the axial force tube 11 is evenly distributed on the cross plate 14, the deviation of the shear force acting on the high tensile bolts that join the cross plate 14 to the frame-side cross plate 21 of the building structure is suppressed, and the joining force of the frictional joint of the high tensile bolts becomes reliable. As a result, the area of ​​the cross plate 14 can be minimized as much as possible, the weight of the component can be reduced, and interference between the cross plate 14 and other components can be prevented. θa≦45(°) ……(11)

[0080] Table 3 shows an example of a buckling restraint brace 14 designed based on the above formulas. By means of formulas (5) to (9), damage caused by contact between the reinforcing tube 12 and the buckling restraint brace 14 can be prevented, and the buckling restraint brace 1 can exert a stable energy absorption capacity during an earthquake, thereby achieving a safe and economical building structure with high vibration reduction performance.

[0081] [Table 3] No. Axial tube Reinforcing pipe and cross plate Separation distance c(mm) (9) End plate and cross plate Welding allowance h(mm) cross plate Material telescopic length L(mm) Maximum strain εmax(%) (5) relative displacement Maximum value δmax(%) (7) end face tilt angle θa(°) With inclined part Quite a length a=h / tanθa (mm) Base length b(mm) (8) 1 JFE-LY225S 2000 2.0 40 45 10 30 17.3 27.7 2 JFE-LY225S 4000 2.0 40 45 10 45 10.0 35.0 3 JFE-LY225S 4000 2.0 80 85 10 30 17.3 67.7

[0082] Figure 22 shows the relationship between the outer diameter D1 (mm) of the axial force tube 11 and the inner diameter D2 (mm) of the reinforcing tube 12 of the buckling restraint support 1 according to an embodiment of the present invention.

[0083] If the difference between the outer diameter D1 (mm) of the axial force tube 11 and the inner diameter D2 (mm) of the reinforcing tube 12 is too small, the excess height of the weld between the axial force tube 11 and the end plate 13 will interfere with the inner surface of the reinforcing tube 12 and hinder the smooth expansion and contraction of the axial force tube 11.

[0084] To prevent this problem, the outer diameter D1 (mm) of the axial force tube 11 and the inner diameter D2 (mm) of the reinforcing tube 12 are preferably set in a manner that satisfies the relationship of the following equation (12). D2-D1≧6(mm) ……(12) Furthermore, if the difference between the outer diameter D1 of the axial force tube 11 and the inner diameter D2 of the reinforcing tube 12 is too large, the reinforcing tube 12 cannot fully exert its effect of constraining the deformation of the axial force tube 11 when an axial load is applied to the axial force tube 11. Moreover, under repeated axial loads during an earthquake, the buckling of the axial force tube 11 becomes significant, the resistance to axial load decreases, and the buckling constraint support 1 cannot fully exert its energy absorption capacity.

[0085] Therefore, in order to fully utilize the energy absorption capacity of the buckling restraint support 1, the outer diameter D1 (mm) of the axial force tube 11 and the inner diameter D2 (mm) of the reinforcing tube 12 are preferably set in a manner that satisfies the relationship of the following equation (13). D2-D1≦25(mm) ……(13) If equations (12) and (13) are combined, the outer diameter D1 (mm) of the axial force tube 11 and the inner diameter D2 (mm) of the reinforcing tube 12 are preferably set in a manner that satisfies the relationship in equation (14) below. 6(mm)≦D2-D1≦25(mm)……(14) Furthermore, equations (13) and (14) can be applied to the dimensions typically used in buckling restraint support 1, specifically when the lengths of the axial force tube 11 and the reinforcing tube 12 are 4000 mm to 14000 mm. When the lengths of the axial force tube 11 and the reinforcing tube 12 are larger than these dimensions, in order to fully utilize the energy absorption capacity of the buckling restraint support 1, the upper limit of (D2-D1) in equations (13) and (14) is ideally set to be smaller than 25 mm.

[0086] In addition, in order to avoid bending and buckling of the reinforcing tube 12, the reinforcing tube 12 is preferably designed in a manner that takes into account the gap e (mm) between the axial force tube 11 and the reinforcing tube 12 and the buckling length l (mm) of the axial force tube 11 and satisfies the following formula (15). [Number 4] …(15) In equation (15), [Number 5] …(16) [Number 6] …(17) PR(N) is the axial force used for the design of the reinforcing tube 12, bMb1(N·mm) is the short-term allowable bending resistance of the reinforcing tube 12, E(N / mm2) is the Young's modulus of the reinforcing tube 12, Ib(mm4) is the moment of inertia of the cross section of the reinforcing tube 12, l(mm) is the buckling length of the axial force tube 11, e(mm) is the gap between the axial force tube 11 and the reinforcing tube 12, and ν0(mm) is the initial deflection of the reinforcing tube (=l / 1000).

[0087] Furthermore, the formula (15) is a calculation formula derived based on the design method described in Non-Patent Document 1.

[0088] Table 4 shows examples of the design of the reinforcing tube 12 based on the above formulas. By means of formulas (15) to (17), the gap e (mm) between the axial force tube 11 and the reinforcing tube 12 can be appropriately set according to the length l (mm) of the axial force tube 11, so that the buckling restraint support 1 can exert a stable energy absorption capacity during an earthquake, thereby realizing a safe and economical building structure with high vibration reduction performance.

[0089] [Table 4] No. Axial tube buckling length l(mm) Axial tube (JFE-LY225) Reinforced pipe (STK400) Design Axial force PR(kN) gap e(mm) initial deflection ν0(mm) mb (16) kb (17) Test ratio outer diameter D(mm) Plate thickness t(mm) outer diameter D(mm) Plate thickness t(mm) 1 6880 318.5 15.4 338.5 7 3006.1 6 6.9 0.007 0.144 1.000 2 6328 318.5 15.4 347.5 7 3006.1 15 6.3 0.008 0.185 1.000 3 5628 318.5 15.4 357.5 7 3006.1 25 5.6 0.009 0.255 1.000 4 4564 318.5 15.4 362.5 7 3006.1 35 4.6 0.012 0.404 1.000

[0090] [Manufacturing method of buckling restraint support] Figure 23 shows an example of a manufacturing process of a buckling restraint support 1 according to an embodiment of the present invention.

[0091] The method for manufacturing the buckling restraint support 1 according to this embodiment is a method for manufacturing the buckling restraint support 1. In the buckling restraint support 1 manufactured by this method, at least one of the set of end plates 13 is formed with a planar shape having a cross-sectional shape smaller than that of the inner periphery of the reinforcing tube 12.

[0092] As shown in Figure 23, in the manufacturing method of the buckling restraint support of this embodiment, firstly, in step S1, end plates 13 are welded to both ends of the axial force tube 11. Next, in step S2, the outer surface of the axial force tube 11 is coated. Next, in step S3, the inner surface of the reinforcing tube 12 is coated. Next, in step S4, the axial force tube 11 is inserted into the interior of the reinforcing tube 12 from the side where the end plates 13, which have a planar shape smaller than the cross-sectional shape of the inner circumference of the reinforcing tube 12, are joined. Next, in step S5, the reinforcing tube 12 is fixed to the axial force tube 11 using the reinforcing tube fixing part. Next, in step S6, cross plates 14 are welded to the end plates 13 on both sides of the axial force tube 11. Next, in step S7, the outer surface of the reinforcing tube 12 and the cross plates 14 are coated.

[0093] Furthermore, in step S6, the cross plate 14 is simultaneously welded to the end plates 13 on both sides of the axial force tube 11. However, alternatively, in step S6, only one end plate 13 of the end plates 13 on both sides of the axial force tube 11 may be joined. In this case, in step S6, an end plate from a set of end plates 13 formed with a planar shape smaller than the cross-sectional shape of the inner circumference of the reinforcing tube 12 is selected and joined to the cross plate 14. Moreover, the joining of the other end plate 13 from the set of end plates 13 to the cross plate 14 can be performed at any stage before step S5.

[0094] As described above, a method for manufacturing a buckling restraint support according to this embodiment is provided.

[0095] 1: Buckling restraint support 11: Axial force tube 11a: Fixing plate 12: Reinforced pipe 12a: Welding hole 13: End plate 13a: Incision site 13b: Backing board 13c: Welded section of reinforcing pipe 14: Cross plate 14a: Base 14b: Top part 14c: Inclined part 15: Plug weld (for the fixing part of the reinforcing tube) 16: Fillet weld (for fixing the reinforcing tube) 17: Hanging components 21: Frame side cross plate 22: splicing board a: The horizontal length of the inclined end of the cross plate relative to the welding allowance h (mm) between the end plate and the cross plate. b: Base length of the cross plate c: Distance between the reinforcing tube and the cross plate D1: Outer diameter of the axial force tube D2: Inner diameter of the reinforcing tube e: Gap between axial force tube and reinforcing tube h: Welding allowance L: Length of the telescopic range L1: The overlap length between the flat portion of the end plate's cut and the fitting portion of the axial force tube. L2: The length of the flat portion of the end plate cutout, excluding the portion that fits into the axial tube / root clearance. L3: Length of the base in the longitudinal direction of the buckling restraint support. Py: Yield load of the end plate S1, S2, S3, S4, S5, S6, S7: Steps t: Plate thickness W: Welding metal θ1, θ2, θa: Inclination angle δmax: The maximum value of the relative displacement

Claims

1. A buckling restraint support comprising: an axial force tube for bearing axial force; a reinforcing tube inserted internally to cover the outer periphery of the axial force tube; a set of end plates joined to the two ends of the axial force tube to close them; and a set of cross plates joined to the two ends of the axial force tube via the end plates and serving as fixing portions to the main body of a building structure, wherein a cutout is provided at the outer edge of the end plates, and when the axial force tube is welded to the end plates using a bevel formed by the cutout and the end face of the axial force tube, the cutout serves as a backing for the bevel, in which the inner surface of the axial force tube overlaps and fits into the cutout, and in which the axial force tube and the end plates are welded together, wherein a step is provided between the portion of the cutout that forms the root gap of the bevel and the portion fitting with the axial force tube.

2. The buckling restraint support as described in claim 1, wherein, The overlap length between the end plate and the axial force tube is 5 mm to 10 mm.

3. The buckling restraint support as claimed in claim 1, wherein, An inclined portion is provided between the base of the cross plate on the side that joins the end plate and the top of the side that joins the building structure, so that the width of the cross plate changes. The thickness te (mm) of the end plate is set to a value calculated using the following formula (1). The maximum value δmax (mm) of the relative displacement δ (mm) between the axial force tube and the reinforcing tube satisfies the following relationship (7) to (9): Pey=2×(1+√2)×te2×σey+π×tp×(r-tp / 2)σpy ……(1) Here, Pey (N) is the yield load of the end plate, r (mm) is the outer radius of the axial force tube, σey (N / mm2) is the yield stress of the end plate, π is pi, tp (mm) is the thickness of the axial force tube, σpy (N / mm2) is the yield stress of the axial force tube, δmax=εmax×L ……(7) c=a+b=h / tanθa+b ……(8) c>δmax ……(9) Here, εmax (%) is the maximum strain of the axial force tube, L (mm) is the length of the expansion range of the axial force tube relative to the reinforcing tube, h (mm) is the welding allowance between the end plate and the cross plate, a (mm) is the horizontal length of the inclined end of the cross plate relative to the welding allowance h (mm) between the end plate and the cross plate, b (mm) is the base length of the cross plate, and θa (°) is the inclination angle of the end face of the cross plate.

4. The buckling restraint support as described in claim 3, wherein, The outer diameter D1 (mm) of the axial force tube and the inner diameter D2 (mm) of the reinforcing tube satisfy the following relationship (14): 6 (mm) ≦ D2 - D1 ≦ 25 (mm) …… (14).

5. The buckling restraint support as claimed in claim 3, wherein the gap e (mm) between the axial force tube and the reinforcing tube satisfies the following relationship (15), [number 1] 5. …(15) Among them, In equation (15), [number 2] 5. …(16) [Number 3] 5. …(17) PR(N) is the design axial force of the reinforcing tube, bMb1(N·mm) is the short-term allowable bending resistance of the reinforcing tube, E(N / mm2) is the Young's modulus of the reinforcing tube, Ib(mm4) is the moment of inertia of the cross section of the reinforcing tube, l(mm) is the buckling length of the axial force tube, e(mm) is the gap between the axial force tube and the reinforcing tube, and ν0(mm) is the initial deflection of the reinforcing tube (=l / 1000).

6. The buckling restraint support as claimed in claim 1, wherein, The reinforcing tube is fixed to the axial force tube by a reinforcing tube fixing part provided at a portion along the length of the reinforcing tube.

7. The buckling restraint support as claimed in claim 6, wherein, The reinforcing tube fixing part is formed by welding the reinforcing tube to the axial force tube using welding holes provided in the reinforcing tube.

8. The buckling restraint support as claimed in claim 6, wherein, The reinforcing tube fixing part is formed by welding one end of the reinforcing tube to the end plate which is engaged with one end of the axial force tube.

9. The buckling restraint support as claimed in any one of claims 1 to 8, wherein, Hanging components are provided on the outer circumferential surface of the reinforcing tube.

10. A method of manufacturing a buckling restraint support, comprising manufacturing a buckling restraint support as described in any one of claims 1 to 9, wherein at least one of a set of end plates is formed in a planar shape having a cross-sectional shape smaller than that of the inner periphery of the reinforcing tube, the axial force tube is inserted into the interior of the reinforcing tube from one side joined with the end plate having a planar shape smaller than that of the inner periphery of the reinforcing tube, and then the cross plate is joined to the end plate having a planar shape smaller than that of the inner periphery of the reinforcing tube.

11. A method for manufacturing a buckling restraint support, wherein the buckling restraint support as claimed in claim 1 is manufactured, wherein in the manufacturing method, when the axial force tube is welded to the end plate using a bevel formed by the cut portion and the end face of the axial force tube, the cut portion serves as a backing for the bevel, and in this state, the inner surface of the axial force tube is overlapped and fitted into the cut portion, and in this state, the axial force tube is welded to the end plate.

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