JP4917177B1 - Buckling restraint brace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a buckling restraining brace capable of enhancing rigidity while applying required energy absorbability and capable of reducing cost. <P>SOLUTION: A buckling restraining brace 1 includes a core member 2 and a pair of restraining members 3 arranged along both surfaces of the core member 2. The core member 2 is band plate-shaped and has a width in a direction orthogonal to a direction in which the core member 2 and the restraining member 3 are arranged side by side, which is larger than a thickness in the direction in which the core member 2 and the restraining member 3 are arranged side by side. An energy absorption part 7 of which geometrical moment of inertia is smaller than the other part is provided in a part in the longitudinal direction of the core member 2, and one or more structural slits 8 along the longitudinal direction are provided in this energy absorption part 7. The width dimensions of a plurality of core member split parts 9, 10 separated by structural slits 8 are different from each other. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a buckling-restrained brace that is incorporated in a framework of a structure and absorbs vibration energy and attenuates vibration in the event of an earthquake or the like.

  As buckling-restraining braces, various types of stiffening have been proposed, such as those in which the periphery of the core is stiffened only with a steel plate, those stiffened with RC, and those covered with steel and mortar or concrete. It has been put into practical use. For example, the thing of patent document 1 stiffens a core material by pinching | interposing a core material from both sides with a pair of restraint material formed by filling concrete in a channel steel material.

Japanese Patent No. 3663491

  In order to enhance the energy absorption performance and rigidity of the buckling-restrained brace, the applicant of the present application has studied a buckling-restraining brace in which the width of a part of the longitudinal direction of the core material 2 is narrowed as shown in FIG. Under development. When the core material 2 has the shape shown in the figure, a portion that absorbs energy becomes clear. As a result, it is possible to increase the brace rigidity while providing the energy absorption performance required as a vibration damping member, and an efficient design of the buckling-restrained brace can be expected.

  A test was performed by actually applying a load to the buckling restraint brace, and the internal conditions of the core material 2 and the restraint material (not shown) were confirmed. As a result, as shown in FIG. 8, the constricted portion 7 of the core material 2 is buckled into a waveform at a certain wavelength In, and the restraint material is pushed at the top 2A of the waveform, so that the mortar of the restraint material is crushed. I understood. When the buckling wavelength In is constant in the width direction of the core material 2, it is necessary to increase the stiffening force of the restraint material in order to counteract the force from the core material 2 applied intensively for each period of the wavelength In. is there. Therefore, it is necessary to increase the amount of mortar of the constraining material or increase the strength of the steel material portion such as the channel steel, and the buckling constraining brace becomes heavy and expensive.

  An object of the present invention is to provide a buckling-restrained brace that can increase rigidity while providing necessary energy absorption and can be reduced in cost.

  The buckling-restraining brace of the present invention includes a core material and a constraint material disposed along both surfaces of the core material, and the core material is orthogonal to the alignment direction rather than the thickness in the alignment direction with the constraint material. A band plate having a wide width in the direction to be provided, provided in one part of the longitudinal direction with an energy absorbing portion having a smaller secondary moment of cross-section than the others, and provided with one or more structural slits along the longitudinal direction in this energy absorbing portion, The plurality of core material divided portions separated by the structural slits have different width dimensions. The restraining material may be a pair of members positioned on both sides of the core material, or may be a single member in which portions positioned on both sides of the core material are integrated with each other.

  When a compressive force acts on the core material, the energy absorbing portion having a small cross-sectional second moment absorbs energy and buckles. The buckling wavelength varies depending on the cross-sectional second moment of the core material. Therefore, by providing a structural slit along the longitudinal direction in the energy absorbing portion and by making the width dimensions of the plurality of core material divided portions separated by the structural slit different from each other, each core material divided portion in the energy absorbing portion Depends on the buckling mode, and the force generated in the restraint material is dispersed. That is, the buckling wavelength varies depending on each core material dividing portion, and the portion of the restraining material pushed at the top of the corrugation is dispersed. Therefore, the stiffening force of the restraining material can be reduced. As a result, the mortar amount of the restraint material can be reduced or the strength can be reduced by reducing the thickness of the steel part such as the grooved steel material of the restraint material, making it possible to reduce the weight and cost of buckling restraint braces. Become.

In this invention, it is good also as providing the narrowing part narrower than others in a part of longitudinal direction of the said core material, and making this narrowing part into the said energy absorption part. Alternatively, the energy absorbing portion of the core material is a portion where the structural slit in the longitudinal direction is provided, and the width dimension is constant from the energy absorbing portion to a portion where the structural slit is not provided, The structural slit may have a gap in a direction orthogonal to the arrangement direction.
In any case, the buckling modes of the respective core material divided portions can be made different from each other. By providing a throttle part in the core material, the energy absorption site is clarified as described above. However, even if a throttle part is not provided, a structural slit with a certain gap is provided, so that the existence of the structural slit is present. In the length portion, the cross-sectional secondary moment is smaller than in other portions, and the energy absorption site becomes clear.

In this invention, you may provide the volt | bolt which is fixed to at least one of a pair of said restraint material, is penetrated by the said structural slit, and prevents the position shift of the said core material.
In the case of this configuration, it is not necessary to attach an attachment for preventing displacement to the core member by welding, so that it is possible to avoid the occurrence of a weak portion due to welding and to exhibit high energy absorption performance.

  The buckling-restraining brace of the present invention includes a core material and a constraint material disposed along both surfaces of the core material, and the core material is orthogonal to the alignment direction rather than the thickness in the alignment direction with the constraint material. A band plate having a wide width in the direction to be provided, provided in one part of the longitudinal direction with an energy absorbing portion having a smaller secondary moment of cross-section than the others, and provided with one or more structural slits along the longitudinal direction in this energy absorbing portion, Since the width dimensions of the plurality of core material divided portions separated by the structural slits are different from each other, the rigidity can be increased while providing necessary energy absorption, and the manufacturing can be performed at low cost.

It is a disassembled perspective view of the buckling restraint brace concerning one Embodiment of this invention. It is sectional drawing of the same buckling restraint brace. (A) is the whole top view of the core material of the buckling restraint brace, (B) is the elements on larger scale. It is explanatory drawing which shows the force which acts on the core material and restraint material of the buckling restraint brace. It is sectional drawing of the buckling restraint brace concerning different embodiment of this invention. (A) is the whole top view of the core material of the buckling restraint brace, (B) is the elements on larger scale. It is a perspective view of a prototype core material. It is a perspective view after the test of the same core material.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of the buckling restrained brace, and FIG. 2 is a sectional view thereof. The buckling restraint brace 1 includes a core material 2, a pair of restraint materials 3 disposed along both surfaces of the core material 2, and an unbond material 4 interposed between the core material 2 and the restraint material 3.

  The core material 2 is made of a steel material having a low yield point such as an SN material (rolled steel material for building structures) or a LYP material (very low yield point steel material), and is orthogonal to the alignment direction rather than the thickness in the alignment direction with the restraint material 3. It is in the shape of a long and narrow strip with a wide width in the direction to be. Both end portions 2a of the core material 2 are portions that become joints with steel frames such as columns and beams, and have a cross-shaped cross section having ribs 5 protruding vertically from the center positions in the width direction of both surfaces. A plurality of bolt holes 6 are drilled in both end portions 2 a of the core material 2.

  As shown in FIG. 3, the core material 2 has a narrowed portion 7 that is narrower than the others at the center in the longitudinal direction. The restricting portion 7 is an energy absorbing portion having a second moment of section smaller than others. The diaphragm portion 7 is provided with one structural slit 8 along the longitudinal direction. The structure slit 8 shown in the figure has a groove shape with a constant gap width, and both ends are formed in an arc shape. In the case of the core material 2 having the narrowed portion 7, the structural slit 8 may have a cut shape having no gap. The structural slit 8 is provided at a position biased to one side in the width direction in the diaphragm portion 7, and the width dimensions A and B of the two core material divided portions 9 and 10 separated by the structural slit 8 are different from each other. Spacers 11 are disposed on both sides of the throttle unit 7. The spacer 11 may be a steel material such as a cut piece of a steel plate or a resin material.

  As shown in FIG. 2, the constraining material 3 is obtained by filling a mortar 14 into a channel steel material 13 having an opening on the core material 2 side. The grooved steel material 13 has a cross-sectional groove shape including a web portion 13a and both flange portions 13b and 13c rising vertically from both ends of the web portion 13a. One flange portion 13b is longer than the other flange portion 13c, and the longer flange portion 13b is in contact with the outer surface of the shorter flange portion 13c of the constraining material 3 facing the flange portion 13b.

  An unbond material 4 is attached to the surface of the mortar 14 facing the core material 2. The unbond material 4 is made of, for example, plate-like or sheet-like butyl rubber. The restraining material 3 and the unbonding material 4 are arranged so as to cover substantially the entire core material 2 excluding the tip portions of both end portions 2 a of the core material 2.

  FIG. 4 is an explanatory diagram showing forces acting on the core material 2 and the restraint material 3 of the buckling restraint brace 1. When a compressive force P in the longitudinal direction acts on the buckling-restraining brace 1, the throttle portion 7 which is an energy absorbing portion of the core material 2 absorbs energy, and the throttle portion 7 is compressed and buckled into a waveform as shown in the figure. Deform. Then, the restraining material 3 is pushed outward at the corrugated top 2A of the core material 2. On the restraining material 3, the same magnitude of the stiffening force C acts on the core material 2 against the force from the core material 2. The magnitude of the stiffening force C is expressed by Equation 1. Here, In is the wavelength of buckling of the core material 2 and is given by Equation 2. S is the amplitude of the core material 2. Is is a cross-sectional second moment of the core material 2 in the weak axis direction.

  From Equation 1, it can be seen that the buckling wavelength In of the core material 2 varies depending on the cross-sectional second moment of the core material 2. Therefore, a structural slit 8 along the longitudinal direction is provided in the diaphragm portion 7 which is an energy absorbing portion, and the width dimensions A and B of the two core material divided portions 9 and 10 separated by the structural slit 8 are different from each other. As a result, the buckling mode is different depending on each of the core material split portions 9 and 10 in the energy absorbing portion, and the force generated in the restraint material 3 is dispersed. That is, the wavelength In of the buckling of the core material 2 varies depending on the core material dividing portions 9 and 10, and the portion of the restraining material 3 pushed by the corrugated top 2A is dispersed. Therefore, the stiffening force of the restraining material 3 can be reduced. Accordingly, the buckling restraint brace 1 is reduced in weight and cost by reducing the strength by reducing the amount of the mortar 14 of the restraint member 3 or reducing the thickness of the channel steel member 13. It becomes possible. By making the energy absorption part the throttle part 7, the cross-sectional secondary moment of the energy absorption part can be reduced more reliably than others, the energy absorption part becomes clear, and efficient design can be performed.

  5 and 6 show different embodiments of the present invention. This buckling restraint brace 1 has a constant width dimension in a central portion excluding both end portions 2a of the core member 2, that is, a portion of a certain length range of the restraint member 3, and in the longitudinal direction part of the center portion in the longitudinal direction. Two structural slits 8 are provided. Each structural slit 8 has a groove shape with a constant width, and both ends are formed in an arc shape. The longitudinal direction portion 20 of the core member 2 provided with the structural slits 8 is an energy absorbing portion having a cross-sectional secondary moment smaller than others due to the presence of the structural slits 8. The energy absorbing part is divided into three core material divided parts 21, 22 and 23 by two structural slits 8. The width dimension D of the core material split parts 21 and 23 on both sides is the same, and the width dimension E of the central core material split part 22 is larger than the width dimension D of the core material split parts 21 and 23 on both sides.

  As shown in FIG. 5, a spacer 24 is disposed in each structural slit 8. The spacer 24 is fixed to the restraint 3 by a bolt 25 embedded and fixed in the mortar 14 of one restraint 3 and a nut 26 to which the bolt 25 is screwed. The bolt 25 is inserted into a bolt insertion hole provided in the spacer 24. As described above, the spacer 24 in the structural slit 8 is fixed to the restraining material 3 by the bolt 25 or the like provided through the structural slit 8 to prevent the core material 2 from being displaced. In the case of this configuration, it is not necessary to attach an accessory for preventing misalignment to the core material 2 by welding, so that it is possible to avoid the occurrence of a weak portion due to welding and to exhibit high energy absorption performance.

  The buckling-restraining brace 1 of this embodiment also has a longitudinal length that is an energy absorbing portion by making the width dimensions D and E of the plurality of core material divided portions 21, 22 and 23 separated by the structural slit 8 different from each other. Even in the direction portion 20, the buckling modes are different between the core material split portions 21 and 23 on the both sides and the central core material split portion 22, and the force generated in the restraint material 3 is dispersed. Therefore, the stiffening force of the restraining material 3 can be reduced. As a result, the buckling restraint brace 1 can be reduced in weight and cost by reducing the strength by reducing the amount of the mortar 14 of the restraint member 3 or by reducing the thickness of the channel steel member 13. become. Since the core material 2 of the buckling restraint brace 1 has a constant width dimension, the energy absorbing portion is located outside the core material in the width direction, which is advantageous in designing the restraint material 3. Also in this embodiment, the number of the structural slits 8 may be one, and the widths of the core material dividing portions on both sides thereof may be different from each other.

  In the above-described embodiments, the separate restraining materials 3 are provided on both sides of the core material 2, but the restraining material portions on both sides of the core material 2 may be integrated with each other.

DESCRIPTION OF SYMBOLS 1 ... Buckling restraint brace 2 ... Core material 3 ... Restraint material 7 ... Drawing part (energy absorption part)
8 ... Structural slits 9, 10, 21, 22, 23 ... core material dividing portion 20 ... longitudinal portion (energy absorbing portion)
25 ... Bolt

Claims (4)

  In a buckling restrained brace having a core material and a constraint material arranged along both sides of the core material, the core material has a width in a direction orthogonal to the alignment direction rather than a thickness in the alignment direction with the constraint material. An energy absorbing portion having a wide strip shape and having a second moment of section smaller than the others is provided in a part of the longitudinal direction, and one or more structural slits are provided in the energy absorbing portion along the longitudinal direction, separated by the structural slits. A buckling-restrained brace characterized in that a plurality of core material divided portions have different width dimensions.   The buckling-restraining brace according to claim 1, wherein a narrowed narrow portion is provided in a part of the core material in the longitudinal direction, and the narrowed portion is used as the energy absorbing portion. In Claim 1, The said energy absorption part of the said core material is a part in which the said structural slit in a longitudinal direction is provided , Comprising: The width dimension is constant from the said energy absorption part to the part in which the said structural slit is not provided. The structural slit is a buckling-restrained brace having a gap in a direction orthogonal to the arrangement direction.   The buckling according to any one of claims 1 to 3, wherein a bolt is provided that is fixed to at least one of the pair of restraining members and is inserted into the structural slit to prevent positional deviation of the core member. Restraint brace.

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