Brace structure

Abstract

To provide a brace structure suppressed in manufacturing cost increase, and resistible against compressive force, while shortening an interval between fulcrums of the braces of the compression side.SOLUTION: A brace structure 1 has four braces 20 arranged in an X-shape along a pair of diagonal lines L1, L1 of a rectangular frame 10, and a connection member for pin-jointing the braces at an intersection part of the braces 20. One end part of the brace 20 is jointed to a connection member 30, and the other end part is jointed to a fitting plate 13 provided at the corner part of a rectangular frame 10. A joint center of the brace 20 with the connection member 30 and a brace joint center of the brace 20 with the fitting plate 13 are arranged on the diagonal line L1, and the tensile strength of the connection member 30 and the fitting plate 13 is equal to the tensile strength of the brace 20 or more.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a brace structure.

Background Art

[0002] Steel frame structures include a ramen structure and a brace structure, which are appropriately selected according to the plan and structurally designed. The brace structure generally forms a tension brace in an X shape. The brace on the extending side functions against the horizontal force, while the brace on the contracting side does not function. In the X-shaped vertical brace, since the distance between the fulcrums is long, it is necessary to strengthen (enlarge) the cross-section of the brace to function under compressive force. Also, in order to shorten the distance between the fulcrums, a method of dividing the X-shaped vertical brace is considered. In any case, since measures against the core displacement at the X-shaped intersection are an issue, a method is adopted in which a single diagonal member in a criss-cross shape functions as both a compressive force and a tensile force instead of an X shape. Furthermore, there is an X-shaped vertical brace that suppresses the buckling of the brace on the compression side by providing a flexible connecting member in the middle of the brace (see, for example, Patent Document 1).

[0003] The brace structure of Patent Document 1 has a connecting member provided at the intersection (central part) of braces arranged in an X shape on the diagonal of a rectangular frame composed of columns and beams. The connecting member is configured to include a flexible cylindrical body made of steel such as low yield point steel and is deformable. When vibration energy (horizontal external force) acts on this brace structure, the connecting member plastically deforms and absorbs the vibration energy. The cylindrical body of the connecting member receives the load from the brace on the tensile side and is stretched in the tensile direction and deformed into an ellipse. On the other hand, in the direction intersecting the tensile direction (contracting side), the cylindrical body is deformed in the direction of being crushed. The brace on the contracting side is pulled following the deformation of the cylindrical body, so it is difficult to cause buckling.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] Bracing structures that divide an X-shaped vertical brace into multiple stages, or bracing structures that reinforce the cross-section of the brace, have the problem of increased manufacturing costs due to an increase in the number of components and joints, or an increase in the cross-section of the brace. Incidentally, in recent years, there has been interest in improving vibration damping performance by resisting compressive force with compression-side braces. However, the brace structure in Patent Document 1 does not resist compressive force, but rather actively deforms the connecting member to apply tensile force to the compression-side brace, thereby preventing compressive force from being applied to the compression brace and making it less prone to buckling.

[0006] Therefore, the object of the present invention is to provide a brace structure that can suppress increases in manufacturing costs and resist compressive forces while shortening the support point spacing of the compression-side brace. [Means for solving the problem]

[0007] The present invention, which solves such problems, is a brace structure comprising four braces arranged in an X shape along a pair of diagonals of a rectangular frame, and connecting members that pin-join the braces at their intersections, wherein one end of each brace is joined to the connecting member and the other end is joined to a mounting plate provided at the corner of the rectangular frame, the joining centers of the brace and the connecting member and the joining centers of the brace and the mounting plate are arranged on the diagonals, and the tensile strength of the connecting member and the mounting plate is greater than or equal to the tensile strength of the brace. The compressive strength of the connecting member and the mounting plate is greater than or equal to the compressive strength of the brace, and the buckling length of the brace is less than or equal to half the diagonal length of the rectangular frame in order to resist compressive force. This brace structure is characterized by the following features.

[0008] In this invention, a pin joint is a joint that does not transmit bending stress and is different from a rigid joint. In this invention, the joint center refers to the centroid of the joint point between the brace and the connecting member, or between the brace and the mounting plate. If there is one joint point, that joint point becomes the joint center; if there are multiple joint points, the centroid of each joint point becomes the joint center. According to the brace structure of this invention, when a horizontal force acts on the rectangular frame, the brace along one diagonal becomes a tension brace, and the connecting member is pulled by the tension brace. At this time, the connecting member is pulled in a linear direction along the diagonal by the tension brace, so its movement in the out-of-plane direction is restrained. Furthermore, since the tensile strength of the connecting member is greater than or equal to the tensile strength of the brace, the connecting member is a plate-like member that does not deform. Also, since the connecting member is joined to the brace diagonally and pulled, it does not rotate. Therefore, the connection points of the compression brace joined to the connecting member become support points where movement is constrained both in-plane and out-of-plane. As a result, the length between the support points of the compression brace becomes the distance between the connecting member and the mounting plate (1 / 2 of the total diagonal length). Consequently, it is smaller than conventional compression braces that span the entire diagonal, and since it is 1 / 2 the length, it has greater resistance to compressive force. This allows the brace to resist both compressive and tensile forces. Therefore, seismic performance can be improved by preventing eccentric buckling due to compressive force while suppressing increases in manufacturing costs.

[0009] In the brace structure of the present invention, it is preferable that the brace comprises a pair of channel steels arranged back-to-back with a predetermined distance between them, and a spacer interposed between the back surfaces of the pair of channel steels. With this configuration, the compression brace is less likely to compress and buckle out of plane by using channel steels, and the weak axis dimension is increased and the radius of gyration of the cross section is increased by arranging the channel steels back-to-back with a predetermined distance between them. This makes it possible to strengthen the cross section while reducing the weight of the brace.

[0010] Furthermore, in the brace structure of the present invention, one end of the pair of channel steels clamps the mounting plate, and the other end of the pair of channel steels clamps the connecting member, and it is preferable that the thickness dimension of the spacer is greater than the thickness dimension of the mounting plate and greater than the thickness dimension of the connecting member. With such a configuration, the middle part of the brace becomes thicker, and the cross-sectional performance (radius of gyration) of the middle part becomes larger. When a compressive force is applied to the brace, the greatest bending force is applied to the middle part of the brace, but by increasing the cross-sectional performance of the middle part, effective buckling prevention is achieved. In addition, since the connecting member and the mounting plate are clamped by the channel steels, axial force can be transmitted with a small number of connecting bolts.

[0011] In the brace structure of the present invention, it is preferable that the brace comprises a pair of channel steels arranged back-to-back with a predetermined interval between them, and a plurality of connecting plates stretched between the sides of the pair of channel steels. With such a configuration, the compression brace is less likely to compress and buckle out of plane by using channel steels, and the weak axis dimension is increased and the radius of gyration of the cross section is increased by arranging the channel steels back-to-back with a predetermined interval between them. This makes it possible to strengthen the cross section while reducing the weight of the brace.

[0012] Furthermore, in the brace structure of the present invention, a clamping plate of a predetermined thickness is provided on the back surface of one end of a pair of channel steels, and the mounting plate is clamped via the clamping plate, and a clamping plate of a predetermined thickness is provided on the back surface of the other end of the pair of channel steels, and the connecting member is clamped via the clamping plate, and it is preferable that the distance between the longitudinal middle parts of the pair of channel steels is greater than the distance between the longitudinal ends of the pair of channel steels. With such a configuration, the middle part of the brace becomes thicker, and the cross-sectional performance (radius of gyration) of the middle part becomes larger. When a compressive force is applied to the brace, the greatest bending force is applied to the middle part of the brace, but by increasing the cross-sectional performance of the middle part, effective buckling prevention is achieved. In addition, since clamping plates are provided at both ends of the channel steels, the stress acting on the back surface of the channel steels can be distributed to the clamping plates, and deformation of the back surface can be suppressed.

[0013] Furthermore, in the brace structure of the present invention, it is preferable that the centroid of the connecting member lies on the extension of the axis of the brace. With such a configuration, the brace and the connecting member are arranged in a straight line, and rotation of the connecting member can be effectively prevented. [Effects of the Invention]

[0014] According to the brace structure of the present invention, it is possible to suppress increases in manufacturing costs, shorten the support point spacing of the compression-side brace, and rationally allow the brace subjected to the compressive force to bear the compressive force. [Brief explanation of the drawing]

[0015] [Figure 1] This is a side view showing a brace structure according to the first embodiment of the present invention. [Figure 2] This is an enlarged side view showing a brace structure according to the first embodiment of the present invention. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 2. [Figure 4] This is a cross-sectional view taken along line IV-IV in Figure 2. [Figure 5](a) to (c) are side views for explaining the installation procedure of the brace structure according to an embodiment of the present invention. [Figure 6] It is an enlarged side view showing the brace structure according to the second embodiment of the present invention. [Figure 7] It is a view showing the brace of the brace structure according to the second embodiment of the present invention, where (a) is a side view, (b) is a view taken in the direction of arrow VII in FIG. 6, and (c) is an end view. [Figure 8] It is a cross-sectional view taken along line IIX-IIX in FIG. 6. [Figure 9] It is a cross-sectional view taken along line IX-IX in FIG. 6. [Figure 10] It is an enlarged side view showing the brace structure according to a modification of the embodiment of the present invention. [Figure 11] It is a side view showing the brace structure according to the third embodiment of the present invention. [Figure 12] It is a cross-sectional view taken along line XII-XII in FIG. 11. [Figure 13] It is a view taken in the direction of arrow XIII-XIII in FIG. 11. [Figure 14] It is a side view showing the brace structure according to the fourth embodiment of the present invention. [Figure 15] It is a side view showing the brace structure according to the fifth embodiment of the present invention. [Figure 16] It is a view showing the joint portion between the horizontal member and the vertical member of the brace structure according to the fifth embodiment of the present invention, where (a) is a partially sectional plan view, (b) is a side view, and (c) is a partially sectional side view. [Figure 17] It is a view showing the joint portion between the brace and the connecting member of the brace structure according to the fifth embodiment of the present invention, where (a) is a side view, (b) is a side view, and (c) is a plan view.

Mode for Carrying Out the Invention

[0016] (First Embodiment) A first embodiment for carrying out the brace structure of the present invention will be described in detail with reference to the attached drawings. As shown in Figures 1 and 2, the brace structure 1 according to the first embodiment comprises a rectangular frame 10, a brace 20, and a connecting member 30.

[0017] The rectangular frame 10 is composed of upper and lower horizontal members (beams) 11, 11 and a pair of vertical members (columns) 12, 12 erected between the horizontal members 11, 11, and has a vertically elongated rectangular shape when viewed from the side. The horizontal members 11 are made of steel, such as H-beams. The vertical members 12 are made of steel, such as square pipes. Mounting plates 13 for attaching braces 20 are provided on the inside of the corners of the rectangular frame 10. The mounting plates 13 are made of steel plates, with their base ends abutting the inner circumferential surface of the corners and their tips extending toward the center of the rectangular frame 10. The tensile strength of the mounting plates 13 is greater than or equal to the tensile strength of the braces 20, and the compressive strength of the mounting plates 13 is greater than or equal to the compressive strength of the braces 20. The mounting plates 13 are positioned so that the middle part in the thickness direction aligns with the middle part in the thickness direction (front and back direction of the paper in Figure 2) of the horizontal members 11 and vertical members 12.

[0018] The braces 20 are arranged in an X shape along a pair of diagonals L1, L1 of the rectangular frame 10. The braces 20 are divided into four sections at the intersection of the diagonals L1, L1 of the rectangular frame 10 (the central part of the rectangular frame 10), and four braces are provided. Each brace 20 is connected at the center of the rectangular frame 10 via a connecting member 30. The diagonal L1 is the line connecting the intersection points P of the center L2 of the horizontal member 11 and the center L3 of the vertical member 12 that are located at opposite corners (only the lower intersection point P is shown in Figure 2).

[0019] As shown in Figures 2 to 4, the brace 20 comprises a pair of channel steel sections 21, 21 and a spacer 22. The channel steel sections 21 have an equilateral U-shaped cross-section that is symmetrical with respect to the web surface, and are arranged back-to-back with a predetermined gap in the thickness direction of the horizontal members 11 and vertical members 12. Because the channel steel sections 21 are equilateral and arranged back-to-back, eccentricity does not occur during joining. One end (outer end) of the pair of channel steel sections 21, 21 in the longitudinal direction clamps the mounting plate 13. The other end (inner end) of the pair of channel steel sections 21, 21 in the longitudinal direction clamps the connecting member 20.

[0020] The spacer 22 is designed to prevent buckling towards the weak axis side (the release side of the channel steel 21) when a compressive force is applied to the channel steel 21, by integrating the pair of channel steels 21, 21 while maintaining the distance between them. The spacer 22 is interposed between the back surfaces (web surfaces) of the channel steels 21, 21. The spacer 22 is made of a steel plate of a predetermined thickness. The spacer 22 is provided in the middle of the longitudinal direction of the brace 20.

[0021] The spacer 22 in this embodiment is made of a circular steel plate and is sandwiched between channel steel sections 21, 21. The spacer 22 has an outer diameter smaller than the width dimension of the channel steel section 21 and is shaped so as not to protrude from the channel steel section 21. The shape of the spacer 22 is not limited to a circle, but may be a rectangle, polygon, ellipse, or other shape. A bolt insertion hole 23 is formed in the spacer 22. The center of the bolt insertion hole 23 is located in the middle of the width direction of the channel steel section 21 and is located on the diagonal line L1. The bolt insertion hole 23 is formed in the center of the spacer 22. A bolt insertion hole is also formed in the middle of the longitudinal direction of each channel steel section 21. A bolt 54 is inserted through the bolt insertion hole of the channel steel section 21 and the bolt insertion hole 23 of the spacer 22 and tightened with a nut 55 to connect the spacer 22 and the channel steel section 21, forming a connecting section. Furthermore, the installation position (formation position of the joint) and number of spacers 22 are not limited to one in the longitudinal middle of the brace 20, but are set appropriately according to the length of the brace 20. When multiple joints are formed, the spacing between adjacent joints is such that the compression buckling of the channel steel 21 does not precede the buckling of the brace 20.

[0022] The bolt 54 is a general-purpose bolt, not a high-strength bolt, and it secures the channel steel sections 21, 21 and the spacer 22 with a single bolt. The thickness (thickness dimension) t2 of the spacer 22 is greater than the thickness (thickness dimension) of the connecting member 30 and greater than the thickness (thickness dimension) t1 of the mounting plate 13. Specifically, the thickness (thickness dimension) t1 of the connecting member 30 and the mounting plate 13 is 9 mm, and the thickness (thickness dimension) t2 of the spacer 22 is 12 mm. As a result, the distance between the two channel steel sections 21, 21 in the longitudinal middle is greater than the distance between the two ends, and the brace 20 has a barrel shape with a bulge in the middle.

[0023] In this embodiment, the channel steel sections 21, 21 and spacers 22 are fixed with bolts 54 and nuts 55, but the fixing method is not limited to bolts 54. The channel steel sections 21 and spacers 22 may be directly welded (spot welded). With such a configuration, the cross-sectional loss of the channel steel sections 21 is eliminated, thus preventing a decrease in tensile strength.

[0024] The joint between the brace 20 and the mounting plate 13 is formed at the tip of the mounting plate 13, which is sandwiched between the longitudinal outer ends of the channel steels 21, 21. A bolt insertion hole 14 is formed at the tip of the mounting plate 13. The center of the bolt insertion hole 14 is located on the diagonal line L1. Multiple bolt insertion holes 14 are formed at intervals along the diagonal line L1 (two in this embodiment). Bolt insertion holes are also formed at the outer end of each channel steel 21. High-strength bolts 51 are inserted through the bolt insertion holes in the channel steels 21 and the bolt insertion holes 14 in the mounting plate 13, and the brace 20 is joined to the mounting plate 13 by tightening with nuts 52. In the figure, the symbol "53" indicates a washer. The position of the center of the high-strength bolt 51 (the position of the center of the bolt insertion hole 14) is the joint between the brace 20 and the mounting plate 13. In other words, the joints between the brace 20 and the mounting plate 13 are spaced apart on a diagonal line L1. This improves the rigidity of the joints in both the in-plane and out-of-plane directions, making the pair of channel steels 21, 21 less susceptible to compression buckling. The center (centroid) of the two joints becomes the joint center between the brace 20 and the mounting plate 13. Since the two joints are located on a diagonal line L1, the joint center is also located on a diagonal line L1. The thickness (thickness dimension) t1 of the mounting plate 13 is set appropriately according to the axial force, but it is preferable that it be the same as the thickness (thickness dimension) of the connecting member 30.

[0025] The connecting member 30 is a member that pin-connects the brace 20 and is provided at the intersection of the diagonals L1, L1. In this invention, a pin connection is a connection that does not transmit bending stress and is different from a rigid connection. The connecting member 30 is made of a rectangular steel plate, and the tensile strength of the connecting member 30 is greater than or equal to the tensile strength of the brace 20, and the compressive strength of the connecting member 30 is greater than or equal to the compressive strength of the brace 20. The connecting member 30 is positioned so that its diagonal coincides with the diagonal L1 of the rectangular frame 10. In other words, the centroid C1 of the connecting member 30 is located on the extension of the axis of the brace 20. In this embodiment, the centroid C1 is located at the intersection of the axes of the two braces 20 (the intersection of the diagonals L1). This causes the brace 20 and the connecting member 30 to be arranged in a straight line. The braces 20 are connected to each of the four corners of the connecting member 30.

[0026] The joints between the brace 20 and the connecting member 30 are formed at the four corners of the connecting member 30, which is sandwiched between the longitudinal inner ends of the channel steel sections 21, 21. Bolt insertion holes (not shown) are formed at the corners of the connecting member 30. The centers of the bolt insertion holes are located on the diagonal line L1. Two bolt insertion holes are formed at intervals along the diagonal line L1. Bolt insertion holes are also formed at the inner ends of each channel steel section 21. High-strength bolts 51 are inserted through the bolt insertion holes in the channel steel sections 21 and the connecting member 30, and the brace 20 is joined to the connecting member 30 by tightening them with nuts. The position of the center of the high-strength bolt 51 (the position of the center of the bolt insertion hole 14) becomes the joint between the brace 20 and the connecting member 30. In other words, the joints between the brace 20 and the connecting member 30 are arranged at intervals along the diagonal line L1. This improves the out-of-plane fixing rigidity of the joint, making the pair of channel steels 21, 21 less susceptible to compression buckling. The center (centroid) of the two joints becomes the joint center between the brace 20 and the connecting member 30. Since the two joints are located on the diagonal L1, the joint center is also located on the diagonal L1. The plate thickness (thickness dimension) of the connecting member 30 is equivalent to the plate thickness (thickness dimension) t1 of the mounting plate 13.

[0027] Next, the construction method of the brace structure 1 of this embodiment will be described with reference to Figure 5. When constructing the brace structure 1, first, the upper brace 20 and the lower set member are assembled in a factory or the like. The upper brace 20 is formed by installing a spacer 22 in the longitudinal middle of a pair of channel steels 21, 21, inserting a bolt 54 through it, and tightening it with a nut 55. The lower set member comprises a lower brace 20 and a connecting member 30. The lower brace 20 has the same shape as the upper brace 20 and is formed using the procedure described above. Then, the connecting member 30 is sandwiched between the inner ends of the channel steels 21 of the lower brace 20, and the brace 20 is temporarily fixed to the connecting member 30 by inserting a temporary bolt and tightening it with a nut. At this time, only one temporary bolt is used for the position of the brace 20, and the brace 20 is temporarily fixed to the connecting member 30 so as to be rotatable. The left and right braces 20 are transported in a state where they are parallel to each other.

[0028] At the construction site, as shown in Figure 5(a), the lower set member brace 20 is spread out and its outer ends are temporarily fixed to the lower mounting plate 13 using high-strength bolts. Then, the outer end of the upper brace 20 is temporarily fixed to the upper mounting plate 13 using a single high-strength bolt, leaving the brace 20 suspended.

[0029] Subsequently, as shown in Figure 5(b), one end of the upper brace 20 is rotated and the inner end of the brace 20 is temporarily fixed to the connecting member 30 using a high-strength bolt. Furthermore, as shown in Figure 5(c), the other end of the upper brace 20 is rotated and the inner end of the brace 20 is temporarily fixed to the connecting member 30 using a high-strength bolt. After adjusting the height, a predetermined number of high-strength bolts are installed and each high-strength bolt is fully tightened. The brace structure 1 is completed through these steps.

[0030] According to the brace structure 1 of this embodiment, when a horizontal force acts on the rectangular frame 10, the braces 20, 20 along one diagonal L1 become tension braces, and the connecting member 30 is pulled by the tension braces. At this time, the connecting member 30 is fixed to the brace 20 by high-strength bolts 51 arranged on the diagonal L1, and is pulled in a linear direction along the diagonal L1, so its movement in the out-of-plane direction is restrained. Furthermore, since the tensile strength of the connecting member 30 is greater than or equal to the tensile strength of the brace 20, the connecting member 30 is a plate-like member that does not deform. Also, since the connecting member 30 is joined to the brace 20 on the diagonal L1 and is pulled linearly along the diagonal L1, it does not rotate. Therefore, the joint points of the compression braces joined to the connecting member 30 become fulcrums where movement is restrained both in-plane and out-of-plane, so the length between the fulcrums of the compression braces is the distance between the connecting member and the mounting plate (1 / 2 of the total diagonal length). Therefore, it is smaller than conventional compression braces that span the entire diagonal, and is half the length, resulting in greater resistance to compressive forces and making it less prone to buckling.

[0031] Furthermore, with this brace structure 1, the brace 20 can resist compressive forces by having a cross-section that can resist compressive forces. In other words, by shortening the buckling length, the brace 20, which could only resist tensile forces, can also resist compressive forces, thus suppressing an increase in the manufacturing cost of the brace 20, while reducing the amount of brace shear wall and creating a wider space.

[0032] Furthermore, in this embodiment, the channel steel 21 has a shape in which the rising height of the flanges on both sides of the web is equal, and is arranged back-to-back with a predetermined interval between them, so that eccentricity does not occur when joining. As a result, when the brace 20 is subjected to compression, the compression brace is less likely to buckle under compression, and the cross-sectional shape becomes capable of resisting efficiently. Therefore, eccentric buckling due to compressive force can be suppressed.

[0033] Furthermore, since a spacer 22 is interposed between the back surfaces of the pair of channel steels 21, 21, the channel steels 21, 21 are spaced apart from each other. This increases the radius of gyration of the brace 20, and efficiently increases its cross-sectional area. In other words, it is possible to strengthen the cross-section while reducing the weight of the brace 20.

[0034] Furthermore, since the spacer 22 is provided in the longitudinal middle of the brace 20, the spacing distance of the channel steel 21 in the middle of the brace 20 can be restricted. As a result, the middle of the brace 20 becomes thicker, and the cross-sectional properties (radius of gyration) of the middle section become larger. When a compressive force is applied to the brace 20, the greatest bending force is applied to the middle of the brace 20, but by increasing the cross-sectional properties of the middle section, the out-of-plane movement of the channel steel 21 is restricted, and effective buckling prevention is achieved. In addition, since the connecting member and the mounting plate are sandwiched by the channel steel, axial force can be transmitted with a small number of connecting bolts. Moreover, the compressive buckling of the channel steel 21 will be connected (linked) at a spacing distance that does not precede the composite cross-section. Therefore, the brace 20 becomes even less prone to buckling.

[0035] Furthermore, the thickness dimension t2 of the spacer 22 provided in the longitudinal middle of the brace 20 is greater than the thickness dimension t1 of the mounting plate 13 at the outer end of the brace 20, and also greater than the thickness dimension of the connecting member 30 at the inner end. As a result, the brace 20 takes on a barrel shape with the middle section of the pair of channel steels 21, 21 widened. Consequently, the channel steels 21 are less likely to buckle under compressive force, and the brace 20 becomes even more resistant to buckling.

[0036] As explained above, the brace structure 1 can suppress increases in manufacturing costs, shorten the support spacing of the compression-side brace 20, and rationally allow the compression force to be borne by the brace 20 that is subjected to the compression force.

[0037] (Second embodiment) Next, a brace structure according to the second embodiment will be described. The brace structure 101 according to the second embodiment differs from that of the first embodiment in the shape of the brace 120. The other components are the same as those of the first embodiment, so the same reference numerals are used and their description is omitted. As shown in Figures 6 to 9, the brace 120 comprises a pair of channel steels 121, 121 and a connecting plate 122. The channel steels 121 have the same cross-sectional shape as the channel steel 21 of the first embodiment and are arranged back to back with a predetermined distance between them.

[0038] As shown in Figures 7 to 9, the connecting plate 122 is stretched between the sides of a pair of channel steel sections 121, 121 (see Figure 7(b) and Figure 8). The connecting plate 122 has a rectangular shape, and both end faces are fixed to the sides of each channel steel section 121 by fillet welding. The pair of channel steel sections 121, 121 are arranged at a predetermined distance apart, and the connecting plate 122 maintains the distance between the channel steel sections 121, 121. The connecting plate 122 is provided so as to sandwich the channel steel section 121 from both sides in the width direction, forming a connecting section. Multiple sets (six sets in this embodiment) of connecting plates 122, 122 that sandwich the channel steel section 121 are provided at predetermined intervals in the longitudinal direction of the channel steel section 121. The distance between adjacent connecting sections is such that the compression buckling of the channel steel section 121 does not precede the buckling of the brace 120.

[0039] A clamping plate 123 of a predetermined thickness is provided on the back surface of the end of the channel steel 121. As shown in Figure 9, the clamping plate 123 is a plate that clamps the mounting plate 13 or the connecting member 30, and is fixed to the opposite back surfaces of the pair of channel steels 121, 121. The clamping plate 123 has a rectangular shape and the same width dimension as the channel steel 121. The clamping plate 123 has bolt insertion holes 124 of the same diameter formed in the position corresponding to the bolt insertion holes formed in the end of the channel steel 121. High-strength bolts for attaching the brace 120 to the mounting plate 13 or the connecting member 30 are inserted through the bolt insertion holes 124 (see Figure 9). The thickness dimension of the clamping plate 123 is greater than the thickness dimension of the channel steel 121. The combined thickness of the two clamping plates 123 and the mounting plate 13 or connecting member 30 becomes the distance between the ends of the channel steel 121.

[0040] The spacing between channel steel sections 121, 121 is slightly greater in the longitudinal middle section than at both longitudinal ends. Specifically, the spacing in the longitudinal middle section is 1 mm greater than the spacing at both longitudinal ends. As a result, the brace 120 has a barrel shape with a bulge in the longitudinal middle section. In a brace 120 with this configuration, the tensile strength of the mounting plate 13 and connecting member 30 is greater than or equal to the tensile strength of the brace 120, and the compressive strength of the mounting plate 13 and connecting member 30 is greater than or equal to the compressive strength of the brace 120.

[0041] With a brace structure 101 configured in this way, in addition to obtaining the same effects as in the first embodiment, by providing (connecting) the connecting plates 122 at intervals such that the compressive buckling of the channel steel 121 does not precede the buckling of the brace 120, the compressive strength of the brace 120 is further increased, and buckling can be prevented.

[0042] Although the first and second embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and each of the above-mentioned components can be modified as appropriate without departing from the spirit of the present invention. For example, in the above embodiments, the joint point between the brace 20 and the connecting member 30 and the joint point between the brace 20 and the mounting plate 13 are arranged on the diagonal L1, but as shown in Figure 10, the arrangement position may be symmetrical on the diagonal L1 instead of on the diagonal L1 (Figure 10 shows the joint point between the brace 20 and the mounting plate 13). Specifically, high-strength bolts 57 are arranged so as to straddle the diagonal L1, and the high-strength bolts 57 that face each other on the diagonal L1 are arranged at equal intervals from the diagonal L1. The high-strength bolts 57 are provided at four corners of the rectangle, and the intersection of the diagonals connecting the installation positions of the high-strength bolts 57 becomes the joint center C2. The joint center C2 is on the diagonal L1. The other components are the same as in the above embodiment, so they are denoted by the same reference numerals and their descriptions are omitted. By providing the high-strength bolts 57 at symmetrical positions on the diagonal L1 in this way, the point on which the stress of the joint acts is on the diagonal L1, and thus the same effects as in the above embodiment can be obtained.

[0043] (Third embodiment) Next, a brace structure according to the third embodiment will be described. The brace structure 201 according to the third embodiment differs from the first and second embodiments in the shape of the brace 220. The other components are the same as in the first embodiment, so the same reference numerals are used and their description is omitted. As shown in Figures 11 to 13, the brace 220 is made of square steel pipes. The brace 220 is arranged in an X shape such that the core of the square steel pipe is aligned with a pair of diagonals L1, L1 of the rectangular frame 10. Note that the brace 220 is not limited to square steel pipes and may be made of round steel pipes.

[0044] In this embodiment, a slit 221 is formed at the end of the brace 220 into which a mounting plate 13 or connecting member 30 is inserted. The slit 221 extends along the axial direction of the brace 220 and is formed on both sides of the brace 220. The brace 220 is fixed to the mounting plate 13 or connecting member 30 by welding with the mounting plate 13 or connecting member 30 inserted into the slit 221. Specifically, as shown in Figures 12 and 13, fillet welding is performed on both sides of the mounting plate 13 or connecting member 30 on the outer surface of the side of the square steel pipe. The fillet welding is performed in a U-shape around the entire circumference of the periphery of the slit 221. In this embodiment, the welded portion becomes the joint point between the brace 220 and the mounting plate 13 or connecting member 30. The center of the straight line connecting the centroids of the U-shaped welded portions on each side of the square steel pipe becomes the joint center. This joint center is located on the diagonal line L1. In a brace 220 with this configuration, the tensile strength of the mounting plate 13 and the connecting member 30 is greater than or equal to the tensile strength of the brace 220, and the compressive strength of the mounting plate 13 and the connecting member 30 is greater than or equal to the compressive strength of the brace 220.

[0045] The joining structure between the brace 220 and the mounting plate 13 or connecting member 30 is not limited to the structure that forms the slit 221. For example, the ends of the square steel pipe may be cut diagonally, and the remaining open plate-like portions may be joined to the mounting plate or connecting member with high-strength bolts.

[0046] With this brace structure 201 configuration, in addition to obtaining the same effects as the first embodiment, the brace 220 is made of square steel pipe, so the strength of the brace 220 itself is high, and the compressive strength of the brace 220 is further increased. Furthermore, since the structure of the brace 220 is simpler compared to the first or second embodiment, the effort required to manufacture the brace 220 is reduced.

[0047] (Fourth embodiment) Next, a brace structure according to the fourth embodiment will be described. As shown in Figure 14, the brace structure 301 according to the fourth embodiment has a large length dimension for the column 312, and multiple layers of rectangular frames 310 are formed vertically between the columns 312, 312. The rectangular frame 310 is composed of a horizontal member 311 stretched between the columns 312, 312 and a portion of the columns 312 on both the left and right sides (a predetermined length portion sandwiched between the upper and lower horizontal members 311). Note that Figure 14 shows the lower part of the building, and the foundation 311a is the lower horizontal member. The lower end of the column 312 is firmly fixed to the foundation 311a via anchor bolts or the like. The lower intersection point P, which is the starting point of the diagonal L1 when the foundation 311a is the lower horizontal member, is the position where the core L3 of the column 312 and the surface of the foundation 311a (the lower end surface of the column 312) intersect. On the other hand, the upper rectangular frame 310 is composed of upper and lower horizontal members 311 and parts of the columns 312 on both the left and right sides.

[0048] The shape of the brace 220 is the same as in the third embodiment. The joining structure between the brace 220 and the mounting plate 13 or connecting member 30 is also the same as in the third embodiment. The horizontal member 311 has the same configuration as the brace 220 and is made of square steel pipe. Slits are formed at both ends of the horizontal member 311, and the mounting plate 13 is inserted into the slits and welded to the column 312.

[0049] With this brace structure 301 configuration, in addition to obtaining the same effects as in the first embodiment, the slenderness ratio can be reduced because the long column 312 is divided by the horizontal member 311, making the column 312 less prone to buckling. Also, the length of the brace 220 can be shortened, thus shortening the buckling length.

[0050] (Fifth embodiment) Next, a brace structure according to the fifth embodiment will be described. As shown in Figure 15, the brace structure 401 according to the fifth embodiment reinforces a rectangular frame 410 of a wooden structure. The rectangular frame 410 is composed of upper and lower horizontal members (beams and sills) 411, 411 and a pair of vertical members (columns) 412, 412 erected between the horizontal members 411, 411, and has a vertically elongated rectangular shape when viewed from the side. Both the horizontal members 411 and the vertical members 412 are made of wooden square timbers. Specifically, the horizontal members 411 on the first floor are sills and are made of cedar with a square cross-section (105 mm × 105 mm), for example. The horizontal members 411 on the second floor and above are beams and are made of Douglas fir with a vertically elongated rectangular cross-section (180 mm × 105 mm). The vertical members 412 are columns and are erected between the sills and beams. The vertical members 412 are made of cedar with a square cross-section (105mm x 105mm), for example.

[0051] The horizontal member 411 and the vertical member 412 are connected by inserting a tenon 412a formed on the end face of the vertical member 412 into a mortise 411a formed in the horizontal member 411 (standard wooden joint). In this embodiment, an L-shaped bracket 413 is also provided at the connection between the horizontal member 411 and the vertical member 412. The L-shaped bracket 413 reinforces the connection strength between the horizontal member 411 and the vertical member 412 and also serves as a mounting plate for joining the brace 420. As shown in Figure 16, the L-shaped bracket 413 comprises a vertical plate portion 414a that abuts against the side surface of the vertical member 412 and a horizontal plate portion 414b that abuts against the upper or lower surface of the horizontal member 411. The L-shaped bracket 413 transmits axial force to the horizontal member 411 (beam) and vertical member 412 (column) via wood screw shear joints by inserting wood screws 415 through the vertical plate portion 414a and the horizontal plate portion 414b, respectively. One end of the brace 420 is welded to the vertical member 412 and the vertical plate portion 414a. The connection to the horizontal member 411, which is the base, is a bolted joint capable of bearing tensile and shear forces in order to transmit the pull-out force, which is the total axial force from the upper and lower L-shaped brackets 413 of the vertical member 412 (the compression side is only the bearing pressure between the column and the L-shaped bracket 413). The bolt 416 is a through bolt and penetrates the horizontal member 411 vertically. The lower end of the bolt 416 is housed in a recess formed in the lower part of the base and is tightened via a washer plate 417 (see Figures 16(b) and (c)). The bolts 416 are provided in pairs, spaced apart in the width direction of the horizontal member 411. The washer plate 417 is stretched between adjacent bolts 416, 416 and fixed to the upper bottom surface of the recess via bolt 418.

[0052] As shown in Figure 15, the brace 420 is arranged in an X shape along a pair of diagonals L1, L1 of the rectangular frame 410, similar to the embodiment described above. The brace 420 is divided into four sections at the intersection of the diagonals L1, L1 of the rectangular frame 410 (the central part of the rectangular frame 10), and four braces are provided. Each brace 420 is connected to the center of the rectangular frame 410 via a connecting member 430. The brace 420 is made of square steel pipe. The brace 420 is arranged in an X shape so that the core of the square steel pipe is aligned along the pair of diagonals L1, L1 of the rectangular frame 410. Note that the brace 420 is not limited to square steel pipe and may be made of round steel pipe. The brace 420 in this embodiment has smaller dimensions (for example, 30 mm x 30 mm, thickness 1.6 mm) than the brace that reinforces the rectangular frame of the steel structure.

[0053] As shown in Figure 16, one end of the brace 420 (the end on the L-shaped bracket 413 side) is cut into a square shape with a right angle at the outer corner when viewed from the side, so that it abuts against the inner corner of the L-shaped bracket 413. Fillet welding is performed along the entire length of the square-cut end of the brace 420, joining the brace 420 to the L-shaped bracket 413. The center of gravity of this weld becomes the joint center between the brace 420 and the L-shaped bracket 413 (mounting plate). The joint center is located on the diagonal line L1. The axial tensile strength of the brace 420 in the L-shaped bracket 413 is greater than or equal to the tensile strength of the brace 420, and the axial compressive strength of the brace 420 in the L-shaped bracket 413 is greater than or equal to the compressive strength of the brace 420.

[0054] As shown in Figures 15 and 17, the other end of the brace 420 (the end on the connecting member 430 side of the center of the rectangular frame 410) is cut into a rectangular shape in side view. The pair of cut surfaces of the other end are perpendicular to each other, and the outer corner of the other end is at a right angle. The inclination angle of the cut surfaces is set according to the inclination angle of the brace 420, so that when the brace 420 is installed, one cut surface 422a becomes horizontal and the other cut surface 422b becomes vertical (see Figure 17(a)). The connecting member 430 is made of a steel plate. The connecting member 430 in this embodiment is smaller than the connecting member 30 for reinforcing the steel frame structure and is a vertically elongated rectangle in side view. The tensile strength of the connecting member 430 is greater than or equal to the tensile strength of the brace 420, and the compressive strength of the connecting member 430 is greater than or equal to the compressive strength of the brace 420. At the joint with the connecting member 430, the other ends of the four braces 420 are positioned opposite each other with a predetermined distance between them. The gaps between the four braces 420 are narrow and cross-shaped. Slits 421 are formed on the sides of the braces 420 that connect to the cut surfaces of the other ends, into which the plate-shaped connecting member 430 is inserted. The slits 421 extend along the axial direction of the brace 420 and are formed on both sides of the brace 420. The braces 420 are fixed to the connecting member 430 by welding with the connecting member 430 inserted into the slits 421. Fillet welding is performed on both sides of the connecting member 430 on the outer surface of the side of the square steel pipe. The corners of the slits 421 on the surface side of the brace 420 are beveled to increase the welding strength. The center of gravity of the welded joint becomes the joint center between the brace 420 and the connecting member 430. The joint center is located on the diagonal L1.

[0055] With a brace structure 401 configured in this way, the same effects and advantages as in the first embodiment can be obtained even in a rectangular frame 410 of a wooden structure. As described above, the brace structure of the present invention can be applied to both steel structures and wooden structures. [Explanation of Symbols]

[0056] 1. Brace structure 10 rectangular frames 13 Mounting plate 20 braces 21 Channel steel 22 Spacers 30 Connecting member L1 Diagonal t1 Thickness dimension of the mounting plate t2 Spacer thickness dimension 101 Brace structure 120 Brace 121 Channel steel 122 Connecting Plate 123 Clamping Plate 201 Brace structure 220 Brace 301 Brace structure 401 Brace structure 420 Brace 430 Connecting member

Claims

1. A brace structure comprising four braces arranged in an X shape along a pair of diagonals of a rectangular frame, and connecting members that pin-join the braces at their intersections, The brace has one end joined to the connecting member and the other end joined to a mounting plate provided at the corner of the rectangular frame. The connection center between the brace and the connecting member and the connection center between the brace and the mounting plate are arranged on the diagonal. The tensile strength of the connecting member and the mounting plate is greater than or equal to the tensile strength of the brace. The compressive strength of the connecting member and the mounting plate is greater than or equal to the compressive strength of the brace. The brace has a buckling length of 1 / 2 or less of the diagonal length of the rectangular frame in order to resist compressive force. A brace structure characterized by the following features.

2. The brace comprises a pair of channel steels arranged back-to-back with a predetermined distance between them, and a spacer interposed between the backs of the pair of channel steels. The brace structure according to feature 1.

3. A brace structure comprising four braces arranged in an X shape along a pair of diagonals of a rectangular frame, and connecting members that pin-join the braces at their intersections, The brace has one end joined to the connecting member and the other end joined to a mounting plate provided at the corner of the rectangular frame. The connection center between the brace and the connecting member and the connection center between the brace and the mounting plate are arranged on the diagonal. The tensile strength of the connecting member and the mounting plate is greater than or equal to the tensile strength of the brace. The brace comprises a pair of channel steels arranged back-to-back with a predetermined distance between them, and a spacer interposed between the backs of the pair of channel steels. One end of the pair of channel steels clamps the mounting plate, The other end of the pair of channel steels is clamping the connecting member, The thickness dimension of the spacer is greater than the thickness dimension of the mounting plate and greater than the thickness dimension of the connecting member. A brace structure characterized by the following features.

4. A brace structure comprising four braces arranged in an X shape along a pair of diagonals of a rectangular frame, and connecting members that pin-join the braces at their intersections, The brace has one end joined to the connecting member and the other end joined to a mounting plate provided at the corner of the rectangular frame. The connection center between the brace and the connecting member and the connection center between the brace and the mounting plate are arranged on the diagonal. The tensile strength of the connecting member and the mounting plate is greater than or equal to the tensile strength of the brace. The brace comprises a pair of channel steels arranged back-to-back at a predetermined interval, and a plurality of connecting plates stretched between the sides of the pair of channel steels. The brace structure according to feature 1.

5. A clamping plate of a predetermined thickness is provided on the back surface of one end of each of the pair of channel steels, and the mounting plate is clamped via the clamping plate. A clamping plate of a predetermined thickness is provided on the back surface of the other end of each of the pair of channel steels, and the connecting member is clamped through the clamping plates. The distance between the longitudinal middle sections of the pair of channel steels is greater than the distance between the longitudinal ends of the pair of channel steels. The brace structure according to feature 4.

6. The centroid of the connecting member is located on the extension of the axis of the brace. The brace structure according to any one of claims 1 to 5, characterized by the features described herein.

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