Joint structure of H-shaped steel brace, mixed frame of reinforced concrete column and steel beam

Abstract

To increase the buckling resistance in the weak axis direction at the joint of an H-section steel brace.SOLUTION: The joint structure of an H-section steel brace 40 is a joint structure of the H-section steel brace 40 to a joint between a reinforced concrete column 20 and an H-section steel beam 30 and includes a first flange 51 provided apart from a flange 31 of the steel beam 30, a bracket 50 having a web 53 joined to the first flange 51 and joining the steel brace 40 to the flange 31 of the steel beam 30, and a reinforcing rib plate 63 that connects the flange 31 of the steel beam 30 and the first flange 51 in the vertical direction and is joined to the web 53 of the bracket 51. One end 51a of the first flange 51 is joined to a flange 41 of the steel brace 40 on the opposite side of the steel beam 30, and the other end 51b is fixed inside a concrete 24 constituting the reinforced concrete column 20, and an end 53b of the web 53 of the bracket 51 on the other end 51b side is also fixed inside the concrete 24.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a joint structure for H-section steel braces and a mixed frame structure of reinforced concrete columns and steel beams. [Background technology]

[0002] In order to increase the rigidity of a column-beam frame having columns and beams that constitute the framework of an architectural structure, it is common to provide braces within the column-beam structural plane. In a column-beam frame provided with a brace, it is necessary to efficiently transmit the axial force generated in the brace to the column-beam frame.

[0003] For example, Patent Documents 1 and 2 disclose a structure in which a rod-shaped brace is joined to a column-beam joint. In Patent Document 1, a gusset plate (brace installation member) provided at the end of a rod-shaped brace is joined to a steel beam and a reinforcing steel plate provided so as to surround a joint portion of the column (column body). In Patent Document 2, the end of a rod-shaped brace is attached to the upper flange of a steel beam via a gusset plate, and a part of the gusset plate is embedded in a reinforced concrete column. In the configurations disclosed in Patent Documents 1 and 2, the gusset plate is a plate arranged along the column-beam structural plane, and has a cross section different from that of the rod-shaped brace. Therefore, it cannot be said that all of the axial force of the brace is efficiently transmitted to the joint through the gusset plate. In particular, when a compressive force acts on a brace, it cannot be said that the bending rigidity in the out-of-plane direction (weak axis direction) perpendicular to the column-beam structural surface is higher than the bending rigidity in the in-plane direction (strong axis direction) along the column-beam structural surface.

[0004] Patent Document 3 discloses a configuration in which an H-shaped steel is used as a brace. More specifically, in Patent Document 3, the ends of the H-shaped steel constituting the brace are butt-joined coaxially to a joint member made of an H-shaped steel, and the joint member is attached to a joint portion of a column-beam frame member via a gusset plate. Furthermore, a conventional configuration different from that of Patent Document 3, in which a steel brace with an H-shaped cross section is joined using a gusset plate, is shown in FIG. 7. The column-beam structure 1 shown in FIG. 7 has a column 2 made of reinforced concrete, a beam 3 made of steel, and a brace 4 made of H-shaped steel. The brace 4 is joined to a joint between the column 2 and the beam 3 via a bracket 5 made of H-shaped steel. A gusset plate 6 is provided between the bracket 5 and the column 2 and between the bracket 5 and the beam 3. The gusset plate 6 is in the form of a plate that follows the column-beam structural surface including the column 2 and the beam 3. A part 6c of the gusset plate 6 is embedded in the column 2 made of reinforced concrete. Even in these configurations, since the gusset plate is in the form of a plate that runs along the column-beam structural plane, it cannot be said that the bending rigidity in the out-of-plane direction (weak axis direction) at the brace joint is higher than the bending rigidity in the in-plane direction (strong axis direction) along the column-beam structural plane. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-331739 [Patent Document 2] JP 2016-98586 A [Patent Document 3] Japanese Patent Application Publication No. 7-42234 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem that the present invention aims to solve is to provide a joint structure for H-section steel braces, and a mixed frame of reinforced concrete columns and steel beams, which can increase the buckling strength in the weak axis direction at the joints of H-section steel braces. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following means. That is, the connection structure of an H-shaped section steel brace of the present invention is a connection structure of an H-shaped section steel brace at a joint between a reinforced concrete column and an H-shaped section steel beam, comprising a first flange provided away from the flange of the steel beam and a web joined to the first flange, a bracket that joins the steel brace to the flange of the steel beam, and a reinforcing rib plate that vertically connects the flange of the steel beam and the first flange and is joined to the web of the bracket, and an end of the bracket is fixed to the reinforced concrete column. According to this configuration, the H-section steel brace is joined to the flange of the steel beam via the bracket. The bracket has a first flange spaced apart from the flange of the steel beam and a web joined to the first flange. A reinforcing rib plate is provided to vertically connect the flange of the steel beam and the first flange and to be joined to the web of the bracket. The first flange and the reinforcing rib plate resist bending stress in the out-of-plane direction of the bracket perpendicular to the column-beam structural plane. In particular, since the end of the bracket is fixed to the reinforced concrete column, it can strongly resist the bending stress as described above and can directly transmit the stress to the reinforced concrete column. Therefore, a column-beam frame with an H-section steel brace having high bending rigidity even in the out-of-plane direction can be realized. In addition, when out-of-plane bending stress or compressive axial force acts on the bracket, the reinforcing rib plate transmits these forces from the H-section steel brace to the bracket, and then disperses and transmits them from the concrete at the joint to its interior via the reinforcing rib plate. This prevents cracks and crushing of the concrete around the bracket. Therefore, it is possible to increase the buckling strength in the out-of-plane direction perpendicular to the column-beam structural plane, which is the weak axis direction, at the joints of H-shaped cross-section steel braces.

[0008] In one aspect of the present invention, the joint structure of an H-section steel brace of the present invention is such that the bracket further comprises a second flange provided at a position closer to the steel beam than the first flange, one end of the second flange is joined to the flange of the steel brace on the steel beam side and the other end is welded to the flange of the steel beam, a first reinforcing plate is provided at the position of the steel beam where the reinforcing rib plate is joined, extending between the upper and lower flanges of the steel beam and connecting them in the vertical direction, and a second reinforcing plate is provided at the position of the steel beam where the second flange is welded, extending between the upper and lower flanges of the steel beam and connecting them in the vertical direction. According to this configuration, one end of the second flange of the bracket is joined to the flange on the steel beam side of the steel brace, and the other end is joined to the second reinforcing plate via the flange of the steel beam. This second flange resists the bending stress in the out-of-plane direction of the bracket perpendicular to the column-beam structural plane, thereby further increasing the bending rigidity of the bracket in the out-of-plane direction. In addition, the bending stress and compressive axial force transmitted from the flange on the steel beam side of the H-section steel brace to the bracket are transmitted to the second reinforcing plate of the steel beam via the second flange of the bracket. In addition, the first reinforcing plate is installed at the position of the steel beam where the reinforcing rib plate is joined, extending between the upper and lower flanges of the steel beam so as to connect them vertically. The bending stress and compressive axial force transmitted to the reinforcing rib plate via the steel brace and bracket are distributed and transmitted from the concrete of the joint to its interior via this first reinforcing plate, together with the reinforcing rib plate. This prevents cracks in the concrete around the bracket and concrete crushing. Therefore, it is possible to further increase the buckling strength of the column-beam structural member in the out-of-plane direction, which is the weak axis direction.

[0009] The mixed frame of reinforced concrete columns and steel beams of the present invention is characterized by comprising a reinforced concrete column, an H-shaped steel beam joined to the reinforced concrete column, and an H-shaped steel brace joined at the joint between the reinforced concrete column and the steel beam by the above-mentioned joint structure of the H-shaped steel brace. With this configuration, it is possible to provide a mixed frame of reinforced concrete columns and steel beams that can increase the buckling strength in the weak axis direction at the joints of the H-section steel braces. Effect of the Invention

[0010] According to the present invention, it is possible to increase the buckling strength in the weak axis direction at the joints of steel braces with H-shaped cross sections. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a joint structure of an H-section steel brace according to an embodiment of the present invention, and a configuration of a mixed frame of reinforced concrete columns and steel beams. [Diagram 2] FIG. 11 is a perspective view showing a joint structure of an H-shaped cross-section steel brace according to a first modified example of the embodiment of the present invention, illustrating the configuration of a mixed frame of reinforced concrete columns and steel beams. [Diagram 3] FIG. 13 is a perspective view showing a joint structure of an H-shaped cross-section steel brace according to a second modified example of the embodiment of the present invention, illustrating the configuration of a mixed frame of reinforced concrete columns and steel beams. [Figure 4] FIG. 13 is a perspective view showing a joint structure of an H-shaped cross-section steel brace according to a third modified example of the embodiment of the present invention, illustrating the configuration of a mixed frame of reinforced concrete columns and steel beams. [Diagram 5] FIG. 13 is a perspective view showing a joint structure of an H-shaped cross-section steel brace according to a fourth modified example of the embodiment of the present invention, illustrating the configuration of a mixed frame of reinforced concrete columns and steel beams. [Figure 6] FIG. 13 is a perspective view showing a joint structure of an H-shaped cross-section steel brace according to a fifth modified example of the embodiment of the present invention, illustrating the configuration of a mixed frame of reinforced concrete columns and steel beams. [Figure 7]FIG. 1 is a perspective view showing the configuration of a joint structure of a steel brace with an H-shaped section using a conventional gusset plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the joint structure of the H-section steel brace of this invention, the end of the H-section steel brace is placed at the joint of the column-beam structure between the reinforced concrete column and the H-section steel beam, and the flange of the steel brace is joined to the first flange of the bracket (the upper flange if the bracket is above the steel beam), and the first flange and web of the bracket are extended into the interior of the reinforced concrete column and fixed in place. In the present invention, by embedding a bracket having a first flange joined to an H-section steel brace in the joint between an RC column and an S-beam frame, the first flange of the bracket, the web extending from the first flange, and the reinforcing rib plate provided vertically between the flange of the steel beam and the first flange of the bracket, which constitute the joint structure of the steel brace, increase the out-of-plane bending strength and bending rigidity. Therefore, the degree of fixation in the out-of-plane weak axis direction of the material end of the H-section steel brace is increased, increasing the buckling resistance in the out-of-plane weak axis direction, and realizing a joint structure of an H-section steel brace with excellent structural performance. Hereinafter, a description will be given of an embodiment of a joint structure of a steel brace with an H-shaped section and a mixed frame of reinforced concrete columns and steel beams according to the present invention with reference to the accompanying drawings.

[0013] FIG. 1 is a perspective view showing the joint structure of an H-section steel brace according to an embodiment of the present invention, and the configuration of a mixed frame of reinforced concrete columns and steel beams. As shown in FIG. 1, a mixed frame 10A with reinforced concrete columns and steel beams includes reinforced concrete columns 20, steel beams 30, and steel braces 40. The reinforced concrete column 20 extends in the vertical direction. The reinforced concrete column 20 includes a plurality of main reinforcements 21 extending in the vertical direction, a plurality of shear reinforcements 22 arranged to surround the plurality of main reinforcements 21, and concrete 24 in which the main reinforcements 21 and the shear reinforcements 22 are embedded. The steel beam 30 extends horizontally and is installed between adjacent reinforced concrete columns 20. In this embodiment, the steel beam 30 is provided on each of the four sides of the reinforced concrete column 20. The four steel beams 30 are joined to each other in the concrete 24 of the reinforced concrete column 20. The steel beam 30 has an H-shaped cross section and includes upper and lower flanges 31, 32 spaced apart in the vertical direction and a web 33 provided between the upper and lower flanges 31, 32. The web 33 is formed along a vertical plane including the extension direction of the steel beam 30. The upper and lower flanges 31, 32 are each formed along a horizontal plane including the extension direction of the steel beam 30.

[0014] The steel brace 40 extends obliquely in a vertical plane (properly referred to as a column-beam structural plane) that includes the extension direction (central axis) of the reinforced concrete column 20 and the extension direction of the steel beam 30. The steel brace 40 has an H-shaped cross section and includes a flange 41 on the opposite side to the steel beam 30, a flange 42 on the steel beam 30 side, and a web 43 provided between the flanges 41, 42. The end of the steel brace 40 is joined via a bracket 50 to a joint J where the reinforced concrete column 20 and the steel beam 30 are joined. In this embodiment, the steel brace 40 is joined to the upper side of the steel beam 30, so the flange 41 on the opposite side to the steel beam 30 is located higher than the flange 42 on the steel beam 30 side. In addition, the flange 41 on the opposite side to the steel beam 30 is located closer to the reinforced concrete column 2 than the flange 42 on the steel beam 30 side.

[0015] The bracket 50 joins the steel brace 40 to the flange 31 of the steel beam 30. The bracket 50 has a first flange 51, a second flange 52, and a web 53. The web 53 is provided within the same column-beam structural plane as the web 43 of the steel brace 40 and the web 33 of the steel beam 30, which constitutes the column-beam frame. The first flange 51 and the second flange 52 are positioned so that their width direction is perpendicular to the column-beam structural plane. The first flange 51 is provided at a distance from the flange 31 of the steel beam 30, particularly upward in this embodiment. The second flange 52 is provided at a position closer to the steel beam 30 than the first flange 51, i.e., lower. The web 53 of the bracket 50 is provided to connect the first flange 51 and the second flange 52. The end 50a of the bracket 50 on the steel brace 40 side is arranged on the same axis as the steel brace 40. At the end 50a, the bracket 50 has the same H-shaped cross-sectional shape as the steel beam 30. At the end 50a of the bracket 50, one end 51a of the first flange 51 is joined to the flange 41 of the steel brace 40 on the opposite side to the steel beam 30. At the end 50a, one end 52a of the second flange 52 is joined to the flange 42 of the steel brace 40 on the steel beam 30 side. At end 50 a , web 53 of bracket 50 is joined to web 43 of steel brace 40 .

[0016] The first flange 51 extends obliquely downward from the flange 41 of the steel brace 40 on the opposite side to the steel beam 30 toward the reinforced concrete column 20. The other end 51b side of the first flange 51 extends horizontally. The other end 51b of the first flange 51 is fixed inside the concrete 24 that constitutes the reinforced concrete column 20. The first flange 51 has a curved portion 51c between the one end 51a and the other end 51b. The curved portion 51c of the first flange 51 is provided with a first reinforcing rib 54 that extends toward the second flange 52. The first reinforcing rib 54 is welded to the web 53. The second flange 52 extends obliquely downward from the flange 42 of the steel brace 40 on the steel beam 30 side toward the reinforced concrete column 20. The other end 52b of the second flange 52 extends vertically. The other end 52b of the second flange 52 is welded to the flange 31 of the steel beam 30. The second flange 52 has a curved portion 52c between the one end 52a and the other end 52b. The curved portion 52c of the second flange 52 is provided with a second reinforcing rib 55 extending toward the first flange 51. The second reinforcing rib 55 is welded to the web 53. In a portion of the web 53 of the bracket 50 closer to the reinforced concrete column 20 than the other end 52b of the second flange 52, the upper end is welded to the first flange 51, and the lower end is welded to the flange 31 of the steel beam 30. An end 53b of the web 53 of the bracket 50 on the other end 51b side of the first flange 51 is fixed inside the concrete 24 together with the other end 51b.

[0017] The steel beam 30 is provided with a first reinforcing plate 61, a second reinforcing plate 62, and a reinforcing rib plate 63. The reinforcing rib plate 63 vertically connects the flange 31 of the steel beam 30, particularly the upper flange 31 in this embodiment, to the first flange 51 of the bracket 50, and is joined to the web 53 of the bracket 50. The first reinforcing plate 61 extends between the upper and lower flanges 31, 32 of the steel beam 30 and connects them in the vertical direction. The first reinforcing plate 61 is provided at a position where the reinforcing rib plate 63 is joined in a plan view. The first reinforcing plate 61 and the reinforcing rib plate 63 are formed in the reinforced concrete column 20 so as to fit along the side surface 24s of the concrete 24 facing the steel brace 40 and the steel beam 30. The first reinforcing plate 61 and the reinforcing rib plate 63 function as bearing plates that receive the axial force input from the steel brace 40 and the steel beam 30. The first reinforcing plate 61 and the reinforcing rib plate 63 have a width equivalent to that of the first flange 51. The second reinforcing plate 62 extends vertically between the upper and lower flanges 31, 32 of the steel beam 30 at a position where the second flange 52 is welded to the flange 31 of the steel beam 30. The second reinforcing plate 62 connects the upper and lower flanges 31, 32 of the steel beam 30 in the vertical direction.

[0018] According to the above-mentioned joint structure of the H-shaped cross-section steel brace 40, the joint structure of the H-shaped cross-section steel brace 40 is a joint structure of the H-shaped cross-section steel brace 40 to the joint between the reinforced concrete column 20 and the H-shaped cross-section steel beam 30, and includes a first flange 51 provided away from the flange 31 of the steel beam 30, a web 53 joined to the first flange 51, a bracket 50 that joins the steel brace 40 to the flange 31 of the steel beam 30, and a web 53 joined to the first flange 51. and a reinforcing rib plate 63 that vertically connects between 31, 32 and the first flange 51 and is joined to the web 53 of the bracket 50. One end 51a of the first flange 51 is joined to the flange 41 of the steel brace 40 opposite the steel beam 30, and the other end 51b is fixed inside the concrete 24 that constitutes the reinforced concrete column 20, and the end 53b of the web 53 of the bracket 50 on the other end 51b side is also fixed inside the concrete 24. According to this configuration, the steel brace 40 with an H-shaped cross section is joined to the flange 31 of the steel beam 30 via the bracket 50. One end 51a of the first flange 51 of the bracket 50 is joined to the flange 41 of the steel brace 40 on the opposite side to the steel beam 30, and the other end 51b of the first flange 51 and an end 53b of the web 53 of the bracket 50 on the other end 51b side of the first flange 51 are fixed inside the concrete 24 constituting the reinforced concrete column 20. In addition, a reinforcing rib plate 63 is provided so as to vertically connect the flange 31 of the steel beam 30 and the first flange 51 and to be joined to the web 53 of the bracket 50. The first flange 51 and the reinforcing rib plate 63 resist bending stress in the out-of-plane direction of the bracket 50 perpendicular to the column-beam structural plane. In particular, the other end 51b of the first flange 51 and the end 53b of the web 53 of the bracket 50 are fixed inside the concrete 24 that constitutes the reinforced concrete column 20, and therefore, by being supported by the concrete 24, the bracket 50 is able to strongly resist the bending stress as described above, and can also directly transmit the stress to the reinforced concrete column 20. Therefore, a column-beam frame with an H-shaped cross-section steel brace 40 that has high bending rigidity even in the out-of-plane direction can be realized. In addition, when out-of-plane bending stress or compressive axial force acts on the bracket 50, these forces are transmitted from the H-shaped cross-section steel brace 40 to the bracket 50 by the reinforcing rib plate 63, and are then dispersed and transmitted from the concrete 24 at the joint J to its interior via the reinforcing rib plate 63. This prevents the concrete 24 from cracking around the bracket 50 and from collapsing. Therefore, at the joints of the H-shaped cross-section steel brace 40, it is possible to increase the buckling resistance in the out-of-plane direction perpendicular to the column-beam structural plane, which is the weak axis direction.

[0019] The bracket 50 further includes a second flange 52 provided at a position closer to the steel beam 30 than the first flange 51, one end 52a of the second flange 52 being joined to the flange 42 of the steel brace 40 on the steel beam 30 side, and the other end 52b being welded to the flange 31 of the steel beam 30. A first reinforcing plate 61 is provided at the position of the steel beam 30 where the reinforcing rib plate 63 is joined, extending between the upper and lower flanges 31, 32 of the steel beam 30 to connect them vertically, and a second reinforcing plate 62 is provided at the position of the steel beam 30 where the second flange 52 is welded, extending between the upper and lower flanges 31, 32 of the steel beam 30 to connect them vertically. According to this configuration, one end 52a of the second flange 52 of the bracket 50 is joined to the flange 32 of the steel brace 40 on the steel beam 30 side, and the other end 52b is joined to the second reinforcing plate 62 via the flange 31 of the steel beam 30. This second flange 52 resists the bending stress in the out-of-plane direction of the bracket 50 perpendicular to the column-beam structural plane, thereby further increasing the bending rigidity of the bracket 50 in the out-of-plane direction. In addition, the bending stress and compressive axial force transmitted from the flange 32 on the steel beam 30 side of the H-shaped cross-section steel brace 40 to the bracket 50 are transmitted to the second reinforcing plate 62 of the steel beam 30 via the second flange 52 of the bracket 50. Furthermore, a first reinforcing plate 61 is provided at the position of the steel beam 30 where the reinforcing rib plate 63 is joined, extending between the upper and lower flanges 31, 32 of the steel beam 30 so as to connect them in the vertical direction. The bending stress and compressive axial force transmitted to the reinforcing rib plate 63 via the steel brace 40 and bracket 50 are dispersed and transmitted from the concrete 24 at the joint to its interior via this first reinforcing plate 61, together with the reinforcing rib plate 63. This prevents cracking of the concrete 24 around the bracket 50 and crushing of the concrete 24. Therefore, it is possible to further increase the buckling strength of the column-beam structural member in the out-of-plane direction, which is the weak axis direction.

[0020] Particularly in this embodiment, the reinforcing rib plate 63 and the first reinforcing plate 61 are formed so as to fit along the side surface 24s of the concrete 24 facing the steel brace 40 side. According to this configuration, the reinforcing rib plate 63 and the first reinforcing plate 61 can effectively transmit the axial force input from the steel brace 40 and the steel beam 30 to the reinforced concrete column 20.

[0021] For example, in the conventional configuration shown in Fig. 7, in order to distribute and transmit the axial force generated in the cross section of the brace 4 to the column 2 and the beam 3, the cross-sectional area of ​​the gusset plate 6, i.e., the product of the thickness and width, must be equal to or greater than the cross-sectional area of ​​the brace 4. However, the thickness of the gusset plate 6 must be equal to or less than the thickness of the web of the beam 3. Therefore, the width of the gusset plate 6 increases as the cross-sectional area of ​​the brace 4 increases. This requires that the shear reinforcement bars of the column 2 be arranged to penetrate the gusset plate 6, which is time-consuming to install. In contrast, in this embodiment in particular, the bracket 50 is provided with a first flange 51, a second flange 52, and a web 53 and has an H-shaped cross section, so that the cross-sectional area of ​​the bracket 50 can be made equal to or greater than the cross-sectional area of ​​the brace 4 without making the width of the web 53 excessively large, as compared to the case shown in Fig. 7. This reduces the number of shear reinforcement bars 22 penetrating the web 53 of the bracket 50, making construction easier. Furthermore, in this embodiment, a reinforcing rib plate 63 is provided in close contact with the side surface 24s of the concrete 24 facing the steel brace 40. The reinforcing rib plate 63 has the same width as the first flange 51 and is joined to the first flange 51. As a result, the portion of the bracket 50 that comes into contact with the concrete 24 has a simple rectangular shape. This makes it easy to process the formwork when pouring the concrete 24 for the reinforced concrete column 20 during construction.

[0022] In addition, the bracket 50 has a web 53 arranged in the same plane as the web 43 of the steel brace 40 and the web 33 of the steel beam 30, and the web 53 of the bracket 50 is welded to the flange 31 of the steel beam 30 and the first flange 51 of the bracket 50, and an end portion 53b of the web 53 of the bracket 50 on the other end 51b side of the first flange 51 is fixed inside the concrete 24 together with the other end 51b. According to this configuration, the steel beam 30 and the H-section steel brace 40 are welded to the web 53, the first flange 51, and the second flange 52 of the bracket 50 at multiple locations, thereby enabling the steel beam 30 and the H-section steel brace 40 to be firmly joined via the bracket 50.

[0023] The first flange 51 has a curved portion 51c between one end 51a and the other end 51b, and a first reinforcing rib 54 extending toward the second flange 52 side is provided on the curved portion 51c. Furthermore, the second flange 52 has a curved portion 52c between one end 52a and the other end 52b, and a second reinforcing rib 55 extending toward the first flange 51 side is provided on the curved portion 52c. With this configuration, the bracket 50 can be made even stronger and its bending rigidity can be increased.

[0024] The above-mentioned mixed frame 10A of reinforced concrete column and steel beam includes a reinforced concrete column 20, a steel beam 30 having an H-shaped cross section joined to the reinforced concrete column 20, and a steel brace 40 having an H-shaped cross section joined at a joint between the reinforced concrete column 20 and the steel beam 30 by the joint structure of the steel brace 40 having an H-shaped cross section as described above. According to this configuration, it is possible to provide a mixed frame 10A of reinforced concrete columns and steel beams that can increase the buckling strength in the weak axis direction at the joints of the steel braces 40 with H-shaped cross sections.

[0025] (First Modification of the Embodiment) The joint structure of the H-section steel brace and the mixed frame of reinforced concrete columns and steel beams of the present invention are not limited to the above-mentioned embodiment described with reference to the drawings, and various modifications are possible within the technical scope. For example, in the above embodiment, the steel brace 40 and bracket 50 are provided only above one of the four steel beams 30 joined to the reinforced concrete column 20, but this is not limited to this. For example, as in the case of a mixed frame 10B of reinforced concrete columns and steel beams shown in Fig. 2, a steel brace 40 and a bracket 50 may be provided on the upper side of each of the four steel beams 30 joined to a reinforced concrete column 20. In this case, the first flanges 51 and webs 53 of the brackets 50 on all four sides may be joined to each other within the concrete 24 of the reinforced concrete column 20. Also, the first flanges 51 and webs 53 of the brackets 50 on all four sides may be arranged at intervals without being joined to each other within the concrete 24 of the reinforced concrete column 20.

[0026] (Second Modification of the Embodiment) Furthermore, as in the case of a mixed frame 10C of reinforced concrete columns and steel beams shown in FIG. 3, among the four steel beams 30 joined to the reinforced concrete column 20, steel braces 40 and brackets 50 may be provided above and below two of the steel beams 30 located within the same column-beam structural plane. In this case, for the steel brace 40C joined to the lower flange 32 of the steel beam 30, the flange 41 on the opposite side to the steel beam 30 is positioned lower than the flange 42 on the steel beam 30 side. With regard to the bracket 50C that joins this steel brace 40C to the joint where the reinforced concrete column 20 and the steel beam 30 are joined, the first flange 51 is provided spaced downward from the flange 32 of the steel beam 30. The second flange 52 is provided at a position closer to the steel beam 30 than the first flange 51, i.e., higher up.

[0027] (Third Modification of the Embodiment) In the above embodiment, the first flange 51 and the second flange 52 have the curved portions 51c, 52c between the one ends 51a, 52a and the other ends 51b, 52b, but this is not limiting. For example, as in a mixed frame 10D of reinforced concrete columns and steel beams shown in FIG. 4, a first flange 51D and a second flange 52D of a bracket 50D may have one end 51a, 52a and the other end 51b, 52b each formed in a flat plate shape, and the one end 51a, 52a and the other end 51b, 52b may be joined by welding at welds 51d, 52d so that they are bent.

[0028] (Fourth Modification of the Embodiment) In the above embodiment, the first reinforcing plate 61 and the reinforcing rib plate 63 are arranged along the side surface 24s of the concrete 24 of the reinforced concrete column 20, but the present invention is not limited to this. For example, as in the case of a mixed frame 10E of reinforced concrete columns and steel beams shown in Fig. 5, a closing plate 28 made of a thin steel plate may be provided to surround the entire periphery on all four sides of the concrete 24 of the reinforced concrete columns 20. In this case, a part 28a of the closing plate 28 functions as a first reinforcing plate and a reinforcing rib plate. By providing such a blocking plate 28, the shear reinforcement 22 on the inside can be omitted. In particular, by providing the blocking plate 28, the blocking plate 28 can be used as a throw-away formwork when pouring the concrete 24 for the reinforced concrete column 20. This makes it unnecessary to assemble and remove the formwork, facilitating construction. Even when such a blocking plate 28 is provided, the steel braces 40 and brackets 50 may be arranged on the upper side of the steel beams 30 on all four sides, as in the mixed reinforced concrete column and steel beam frame 10F shown in Figure 6, or may be provided in other locations. In addition, the configurations described in the above embodiments can be selected or changed as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0029] 10A~10F Steel beam mixed frame 51b The other end of the first flange 20 Reinforced concrete column 52, 52D Second flange 24 Concrete 52a One end of second flange 28 Closure plate (first reinforcing plate, reinforcing rib plate) 30 Steel beam 52b Other end of second flange 31, 32...Flanges of steel beam (upper and lower flanges of steel beam) 40, 40C Steel brace 53 Bracket web 41 Flange opposite to steel beam 53b End of other end of web 42 Flange on steel beam side 61 First reinforcement plate 50, 50C, 50D Bracket 62 Second Reinforcement Plate 51, 51D First flange 63 Reinforcement rib plate 51a One end of the first flange

Claims

1. A joint structure of an H-shaped steel brace to a joint between a reinforced concrete column and an H-shaped steel beam, A bracket having an H-shaped cross-sectional shape, a first flange provided at a distance from the flange of the steel beam, and a web joined to the first flange, and joining the steel brace to the flange of the steel beam; A reinforcing rib plate that vertically connects the flange and the first flange of the steel beam and is joined to the web of the bracket, The first flange is joined to a flange of the steel brace opposite the steel beam, A joint structure for an H-shaped section steel brace, characterized in that the end of the bracket is fixed to the reinforced concrete column.

2. The bracket further includes a second flange provided at a position closer to the steel beam than the first flange, One end of the second flange is joined to a flange of the steel brace on the steel beam side, and the other end is welded to the flange of the steel beam, A first reinforcing plate is provided at the position where the reinforcing rib plate is joined to the steel beam, extending between the upper and lower flanges of the steel beam and connecting them in the vertical direction; The joint structure of the H-shaped section steel brace according to claim 1, characterized in that a second reinforcing plate is provided at the position of the steel beam where the second flange is welded, extending between the upper and lower flanges of the steel beam and connecting them in the vertical direction.

3. Reinforced concrete columns, A steel beam having an H-shaped cross section joined to the reinforced concrete column; At the joint between the reinforced concrete column and the steel beam, an H-shaped cross-section steel brace is connected by the joint structure of the H-shaped cross-section steel brace according to claim 1 or 2; A mixed structure of reinforced concrete columns and steel beams.

Images