Pillar and beam joint structure

Abstract

To provide a joint structure between a column and beams capable of improving the workability of the joint between a column and beams while ensuring the tensile stiffness in beam axial direction and the bending durability of the column.SOLUTION: A joint structure is a joint structure 1 between a concrete-filled steel pipe column and a steel frame beam in which concrete 23 is filled inside a steel pipe 21. A beam 3 has a flange 33, a web 34, and a diaphragm member 4 provided at joint 11 between a column 2 and the beam 3. The diaphragm member 4 includes: an outer diaphragm part 4a annular in planar view which protrudes outward from the outer circumference surface of the steel pipe 21 with flange 33 joined to edge parts 411, 421; and a reinforcement part 4b which is bridged between inner peripheral edge portions 412, 422 of the outer diaphragm portion 4a extending radially.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a joint structure between a column and a beam. [Background technology]

[0002] Conventionally, in RCST structures that combine CFT (concrete filled steel tubular) columns and S (steel beams) beams, two types of column-to-beam connections have been proposed: the beam penetration type, in which the beam penetrates the column, and the external diaphragm type, in which the beam is connected to a diaphragm connected to the outside of the column (see, for example, Patent Documents 1 and 2). Of these, the external diaphragm type employs circular or rectangular external diaphragms that are circular or rectangular in plan view in the vertical direction. Circular external diaphragms fit better with exterior walls than rectangular external diaphragms, allowing for a more efficient structural plan. In addition, when used for diagonal beams, the details of the joints between columns and beams can be simplified. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-2628 A [Patent Document 2] JP 2020-2638 A Summary of the Invention [Problem to be solved by the invention]

[0004] On the other hand, compared to rectangular diaphragms, circular diaphragms are more likely to deform inward and outward from the plate surface when resisting tensile forces from beams, which reduces the structural rigidity.

[0005] Furthermore, when installing guides to manage the required anchorage length of the column joint rebar, there is no penetrating beam within the joint as with the beam penetration type, and the beam flange cannot be used, so a separate jig for reinforcing bar arrangement must be installed within the joint, which creates problems with workability. Even when penetrating reinforcement is provided within the circular diaphragm in the beam axis direction in order to solve the above problem, if the width of the reinforcement is relatively large, it is not possible to place reinforcing bars at the outermost ends within the column cross section, which results in inefficient securing of the column bending strength.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a column-to-beam joint structure that can increase the tensile rigidity in the beam axial direction while ensuring the column bending strength at the column-to-beam joint, and can improve the workability of the column-to-beam joint. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the column-to-beam joint structure of the present invention is a joint structure between a column of concrete-filled steel pipe construction in which concrete is filled inside the steel pipe and a beam of steel frame construction, wherein the beam has a flange and a web, and a diaphragm member provided at the joint between the column and the beam, and the diaphragm member has an outer diaphragm portion that protrudes outward from the outer circumferential surface of the steel pipe and has a ring-shaped outer diaphragm portion joined to its outer circumferential edge portion, and a reinforcing portion that is installed on the inner circumferential edge portion of the outer diaphragm portion and formed extending radially.

[0008] With the above-mentioned configuration, the diaphragm member can be prevented from deforming in the in-plane direction and out-of-plane direction when resisting the tensile force from the beam. In addition, the provision of the reinforcing portion can improve the column bending strength. Therefore, the tensile rigidity of the joint between the column and the beam can be improved while maintaining the column bending strength. In addition, by installing the reinforcing part on the inner peripheral edge, the reinforcing part provided on the inside of the steel pipe can be used when installing a guide for managing the required anchorage length of the column joint rebar during construction of the joint structure. Therefore, it is possible to improve the workability of the joint between the column and the beam, such as reducing the labor required for on-site construction work.

[0009] In addition, in the column-beam joint structure of the present invention, the reinforcing portion may be provided on a line connecting the planar view end portion of the joint between the flange and the outer peripheral portion at the inner peripheral portion and the column core.

[0010] In the above configuration, the configuration of "on the line connecting the end of the joint between the flange and the outer peripheral edge in plan view and the column core of the column" is included in the critical section of the joint structure. Generally, this is a critical section for bending stress. Therefore, by adopting the above configuration, the reinforcing part is arranged to overlap with the critical section of the joint structure, which makes it possible to achieve a more rational structure for ensuring the desired column bending strength.

[0011] In addition, in the column-beam joint structure of the present invention, the outer diaphragm portion may have an outer shape that is circular when viewed from above.

[0012] With the above-mentioned configuration, the diaphragm member can be framed in a lean configuration that improves the fit with the exterior wall, etc. Also, when used for a complex structure such as a diagonal beam, the details of the joint between the column and the beam can be simplified.

[0013] In addition, in the column-beam joint structure according to the present invention, the shapes of the joint surfaces of the outer peripheral edge portion and the flange may be approximately the same.

[0014] With the above-mentioned configuration, a joint structure between the pillar and the beam can be formed with improved joinability between the flange and the outer peripheral edge portion of the diaphragm member.

[0015] In addition, in the column-to-beam joint structure of the present invention, the reinforcing portion may be bridged on the inner peripheral edge portion at a position closely opposed to the joint position where the beam is joined to the outer peripheral edge portion in the beam axis direction.

[0016] By adopting the above configuration, the tensile rigidity and column bending strength of the diaphragm member can be efficiently improved, and the desired tensile rigidity and column bending strength can be ensured at the joint between the column and the beam. Effect of the Invention

[0017] According to the present invention, it is possible to provide a column-beam joint structure that can increase the tensile rigidity in the beam axial direction while ensuring the column bending strength at the column-beam joint, and that can improve the workability of the column-beam joint. [Brief description of the drawings]

[0018] [Figure 1] 3 is a vertical cross-sectional view showing an example of a joint structure between a column and a beam according to an embodiment of the present invention, taken along line BB in FIG. 2. [Diagram 2] FIG. 2 is a horizontal cross-sectional view showing an example of a joint structure between a column and a beam according to an embodiment of the present invention, taken along line AA in FIG. [Diagram 3] 1 is a perspective view of a diaphragm member in an example of a joint structure between a pillar and a beam according to an embodiment of the present invention. FIG. [Figure 4] 1A is a vertical cross-sectional view of the comparative example of an analytical model of an example of a joint structure between a column and a beam according to an embodiment of the present invention, and FIG. 1B is a vertical cross-sectional view of the comparative example taken along line EE in FIG. 1B. FIG. 1B is a horizontal cross-sectional view of the comparative example taken along line CC in FIG. [Diagram 5] 1 is a graph showing analysis results (relationship between displacement and load) of an analysis model in an example of a joint structure between a column and a beam according to an embodiment of the present invention and a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a joint structure between a pillar and a beam according to an embodiment of the present invention will be described with reference to Figs. As shown in Figures 1 and 2, the column-to-beam joint structure 1 of this embodiment is a joint 11 (hereinafter referred to as the "column-beam joint 11") between a column 2 made of concrete-filled steel pipe construction (CFT construction) and a beam 3 made of steel frame construction (S construction). In this embodiment, the column-beam joint 11 is located between the upper column 2 and the lower column 2 extending in the vertical direction, between the beams 3, 3 extending in one horizontal direction relative to the column 2, and between the beams 3, 3 extending in another horizontal direction relative to the column 2. In the following description, unless otherwise specified, the one horizontal direction relative to the column 2 is the X direction, the other horizontal direction relative to the column 2 perpendicular to the X direction is the Y direction, and the vertical direction relative to the beam 3 (the direction in which the column 2 is arranged) is the Z direction.

[0020] The column 2 includes a steel pipe 21 extending in the Z direction relative to the beam 3, reinforcing bars 22 disposed inside the steel pipe 21 and extending in the Z direction, and concrete 23 filled inside the steel pipe 21. Note that hatching of the concrete 23 is omitted in Figs. 1 and 2 and Fig. 4 which explains a comparative example of an analysis model in this embodiment to be described later.

[0021] The beam 3 is an H-shaped steel beam, and includes a flange 33 with an upper flange 31 and a lower flange 32, and a web 34. The beam 3 is disposed perpendicular to the adjacent beams 3 in a plan view in the Z direction. The beams 3, 3 extending in the X direction have a beam axis direction in the X direction, and the beams 3, 3 extending in the Y direction have a beam axis direction in the Y direction. The vertical lengths T1 (flange thickness) of the upper flange 31 and the lower flange 32 are approximately the same.

[0022] The column-beam joint 11 includes a joint steel pipe 24 and a diaphragm member 4 described later. The diaphragm member 4 includes an outer diaphragm portion 4a and a reinforcing portion 4b. The outer diaphragm portion 4a includes an upper diaphragm portion 41 and a lower diaphragm portion 42. The reinforcing portion 4b includes an upper reinforcing portion 43 and a lower reinforcing portion 44. In this embodiment, the upper diaphragm portion 41 and the lower diaphragm portion 42, and the upper reinforcing portion 43 and the lower reinforcing portion 44 are arranged coaxially in the Z direction. In addition, the upper diaphragm portion 41 and the upper reinforcing portion 43, and the lower diaphragm portion 42 and the lower reinforcing portion 44 are each provided integrally in the column-beam joint 11.

[0023] The joint steel pipe 24 is provided between the upper column 2 in the Z direction and the lower column 2, and the column-beam joint 11 is joined to the beams 3,3 extending in the X direction and the beams 3,3 extending in the Y direction via an upper diaphragm portion 41 and a lower diaphragm portion 42 at four locations at both ends in the X direction and both ends in the Y direction. The upper diaphragm portion 41 is joined to the upper flange 31, and the lower diaphragm portion 42 is joined to the lower flange 32. The upper diaphragm portion 41 and the lower diaphragm portion 42 are formed so that their outer shapes in a plan view in the Z direction are approximately circular. The joint steel pipe 24 is formed with a diameter that is approximately the same as that of the steel pipe 21 of the column 2, is arranged coaxially in the Z direction with the steel pipe 21, and extends over approximately the entire column-beam joint 11 in the Z direction. The inside of the joint steel pipe 24 is provided continuously with the reinforcing bars 22 provided inside the steel pipe 21 of the column 2 at the upper and lower parts in the Z direction, and is filled with concrete 23 in the same manner as the inside of the steel pipe 21. The end portion (web end 341) of the web 34 may be welded to the outer circumferential surface of the opposing joint steel pipe 24.

[0024] As shown in FIG. 1 to FIG. 3, the upper diaphragm portion 41 and the lower diaphragm portion 42 are provided so as to protrude in an annular shape from the entire outer periphery of the joint steel pipe 24. In addition, the upper diaphragm outer peripheral edge portion 411 (hereinafter referred to as the "outer peripheral edge portion 411"), which is the outer peripheral edge portion of the upper diaphragm portion 41, is cut along the YZ plane at the portion where it joins with the beams 3, 3 extending in the X direction, to form the upper beam joint portion 45. Similarly, the lower diaphragm outer peripheral edge portion 421 (hereinafter referred to as the "outer peripheral edge portion 421"), which is the outer peripheral edge portion of the lower diaphragm portion 42, is cut along the YZ plane at the portion where it joins with the beams 3, 3 extending in the X direction, to form the lower beam joint portion 46. As above, the outer peripheral edge portion 411 and the outer peripheral edge portion 421 are also cut along the XZ plane at the portion where it joins with the beams 3, 3 extending in the Y direction, to form the upper beam joint portion 45 and the lower beam joint portion 46. As described above, a total of four upper beam joints 45 and four lower beam joints 46 are formed in the X direction and the Y direction, respectively.

[0025] The upper beam joint 45 is welded to the end of the upper flange 31 of the closely opposed beam 3 (hereinafter referred to as the "upper flange end 311"). The joint surface shape of the upper beam joint 45 is formed to a size that approximately matches the joint surface shape of the opposed upper flange end 311. The lower beam joint 46 is welded to the end of the lower flange 32 of the closely opposed beam 3 (hereinafter referred to as the "lower flange end 321"). The joint surface shape of the lower beam joint 46 is formed to a size that approximately matches the joint surface shape of the opposed lower flange end 321. In this embodiment, the length (diaphragm thickness) T2 of the diaphragm member 4 in the Z direction is approximately equal to the flange thickness T1 of the upper flange 31 and the lower flange 32. The upper diaphragm portion 41 and the upper flange 31, and the lower diaphragm portion 42 and the lower flange 32 are each formed to be flush with each other in the beam axis direction when viewed from the front.

[0026] The upper diaphragm portion 41 has an upper diaphragm inner peripheral edge portion 412 (hereinafter referred to as the "inner peripheral edge portion 412") joined to the Z-direction upper end portion of the entire outer periphery of the joint steel pipe 24. The lower diaphragm portion 42 has a lower diaphragm inner peripheral edge portion 422 (hereinafter referred to as the "inner peripheral edge portion 422") joined to the Z-direction lower end portion of the entire outer periphery of the joint steel pipe 24.

[0027] The upper reinforcing portion 43 is provided inside the upper diaphragm portion 41 (within the annular shape) and is disposed inside the joint steel pipe 24 when viewed in a plane in the Z direction. Similarly, the lower reinforcing portion 44 is provided inside the lower diaphragm portion 42 (within the annular shape) and is disposed inside the joint steel pipe 24 when viewed in a plane in the Z direction. The upper reinforcing part 43 includes an upper reinforcing member 432 extending radially between an upper core part 431 provided on the column core 2a of the column 2 and an inner peripheral edge part 412. Similarly, the lower reinforcing part 44 includes a lower reinforcing member 442 extending radially between a lower core part 441 provided on the column core 2a and an inner peripheral edge part 422. In this embodiment, the upper reinforcing part 43 and the lower reinforcing part 44 are formed so that their shapes in a Z-direction plan view are substantially the same. In addition, as long as the diaphragm member 4 has the desired performance, the configurations of the upper reinforcing portion 43 and the lower reinforcing portion 44 are not limited to the present embodiment. For example, the upper core portion 431 and the lower core portion 441 may be omitted, and the upper reinforcing member 432 and the lower reinforcing member 442 may be formed in a radial shape that is gathered at one point at the column core 2a.

[0028] The upper reinforcement member 432 is provided on a line L1 connecting the end 312 of the beam width W1 in the X or Y direction (the member length in the direction perpendicular to the beam axis direction and the flange thickness T1 direction at the end adjacent to the upper beam joint 45 of the upper flange 31) at the end adjacent to the upper beam joint 45 of the upper flange 31 and the column core 2a. Similarly, the lower reinforcement member 442 is provided on a line L2 connecting the end 322 of the beam width W2 in the X or Y direction (the member length in the direction perpendicular to the beam axis direction and the flange thickness T1 direction at the end adjacent to the lower beam joint 46 of the lower flange 32) and the column core 2a at the end adjacent to the lower beam joint 46 of the lower flange 32. In this embodiment, the upper reinforcing member 432 and the lower reinforcing member 442 are formed with the same configuration for the beams 3 extending in the X direction and the beams 3 extending in the Y direction. The beam width W1 and the beam width W2 are approximately the same. In this embodiment, the upper reinforcing portion 43 and the lower reinforcing portion 44 have approximately the same shape when viewed in a Z direction plane, so the lines L1 and L2 overlap when viewed in a Z direction plane. Hereinafter, the lines L1 and L2 are referred to as lines L, and an example is shown in FIG. Furthermore, the cross section in the Z direction including line L is a dangerous cross section for bending stress of the beam-column joint 11, and the upper reinforcement member 432 and the lower reinforcement member 442 are disposed in an extension of the dangerous cross section. Note that the reinforcing bars 22 provided continuously inside the steel pipe 21 and the joint steel pipe 24 are inserted into an area inside the diaphragm member 4 that does not interfere with the upper reinforcement part 43 and the lower reinforcement part 44.

[0029] One end of the upper reinforcing portion 43 facing the inner peripheral edge portion 412 is joined to the inner peripheral edge portion 412. That is, the upper reinforcing portion 43 is installed inside the inner peripheral edge portion 412. The upper diaphragm portion 41 and the upper reinforcing portion 43 are integrally formed by processing a steel plate having a desired strength against external forces into a flat plate shape. The Z-direction upper surfaces of the upper diaphragm portion 41 and the upper reinforcing portion 43 are provided so as to be flush with each other when viewed from the front. The Z-direction lower surfaces are also provided so as to be flush with each other when viewed from the front, similar to the Z-direction upper surfaces. Similarly, one end of the lower reinforcement portion 44 that faces the inner peripheral edge portion 422 is joined to the inner peripheral edge portion 422. That is, the lower reinforcement portion 44 is disposed inside the inner peripheral edge portion 422. Furthermore, the lower diaphragm portion 42 and the lower reinforcement portion 44 are integrally formed by processing a steel plate having a desired strength against external forces into a flat plate shape. The Z-direction upper surfaces of the lower diaphragm portion 42 and the lower reinforcement portion 44 are provided so as to be flush with each other when viewed from the front. Furthermore, the Z-direction lower surfaces are also provided so as to be flush with each other when viewed from the front, similar to the Z-direction upper surfaces. In addition, the configurations of the upper reinforcing portion 43 and the lower reinforcing portion 44 are not limited to this embodiment as long as the diaphragm member 4 has the desired performance. For example, the upper reinforcing portion 43 and the lower reinforcing portion 44 may have one end facing the inner peripheral edge portion 412 and the inner peripheral edge portion 422, respectively, joined to the inner surface of the joint steel pipe 24.

[0030] Next, the operation and effect of the column-to-beam joint structure 1 according to the present embodiment will be described. In the column-to-beam joint structure 1 according to this embodiment, the diaphragm member 4 includes an annular upper diaphragm portion 41 that protrudes outward from the outer circumferential surface of the joint steel pipe 24 and to which the beam 3 is joined, and an upper reinforcing portion 43 is installed inside the upper diaphragm portion 41. Similarly, the diaphragm member 4 includes an annular lower diaphragm portion 42 that protrudes outward from the outer circumferential surface of the joint steel pipe 24 and to which the beam 3 is joined, and a lower reinforcing portion 44 is installed inside the lower diaphragm portion 42. With the above-mentioned configuration, the diaphragm member 4 can be prevented from deforming inward and outward of the plate surface when resisting the tensile force from the beam 3. Therefore, the tensile rigidity (framework rigidity) of the column-beam joint 11 can be improved while ensuring the column bending strength.

[0031] The upper reinforcing member 432 is provided on a line L connecting the end 312 of the beam width W1 in the X or Y direction at the end facing closely to the upper beam joint 45 of the upper flange 31 and the column core 2a. Similarly, the lower reinforcing member 442 is provided on a line L connecting the end 322 of the beam width W2 in the X or Y direction at the end facing closely to the lower beam joint 46 of the lower flange 32 and the column core 2a. Therefore, the upper reinforcement portion 43 and the lower reinforcement portion 44 form an outer diameter shape in a plan view in the Z direction that extends radially and coaxially with the upper flange 31 and the lower flange 32, respectively. In addition, the reinforcing bars 22 provided inside the steel pipe 21 and the joint steel pipe 24 are inserted into an area inside the diaphragm member 4 that does not interfere with the upper reinforcement portion 43 and the lower reinforcement portion 44. With the above configuration, there is no need to pass the beam 3 through the steel pipe 21 when constructing the column-beam joint 11, and when installing a guide for managing the necessary anchorage length of the reinforcing bar 22 installed inside the column 2, the radial-shaped upper reinforcement part 43 and lower reinforcement part 44 located on the inside of the joint steel pipe 24 can be used to install the guide in accordance with the position of the reinforcing bar 22, thereby improving the workability of the column-beam joint 11, such as reducing the labor required for on-site construction work. In addition, with the above-mentioned configuration, the diaphragm member 4 has the upper reinforcement portion 43 and the lower reinforcement portion 44 arranged at the critical cross section for bending stress at the column-beam joint 11, so that the desired bending strength against bending stress from the column 2 can be ensured and the desired tensile rigidity in the beam axis direction can be ensured.

[0032] In the column-beam joint structure 1 according to this embodiment, the diaphragm member 4 is joined to the beam 3 from four directions on both sides of the X and Y directions. The upper reinforcing portion 43 is joined to the inner peripheral edge portion 412 at four locations that face the four positions of the outer peripheral edge portion 411 where the beam 3 is joined. Similarly, the lower reinforcing portion 44 is joined to the inner peripheral edge portion 422 at four locations that face the four positions of the outer peripheral edge portion 421 where the beam 3 is joined. The beams 3 are disposed perpendicular to the adjacent beams 3 in a plan view in the Z direction. In addition, the beams 3, 3 extending in the X direction have a beam axis direction in the X direction, and the beams 3, 3 extending in the Y direction have a beam axis direction in the Y direction. With the above configuration, the diaphragm member 4 and the four beams 3 are joined in a cross shape, so that the rigidity of the diaphragm member 4 can be efficiently improved and the desired rigidity at the column-beam joint 11 can be ensured.

[0033] In the column-beam joint structure 1 according to this embodiment, the upper diaphragm portion 41 and the lower diaphragm portion 42 are formed in an annular shape from the entire outer periphery of the joint steel pipe 24. The outer peripheral edge portion 411 is cut along the YZ plane at the portion where it joins the beams 3, 3 extending in the X direction, forming the upper beam joint portion 45. The outer peripheral edge portion 421 is also cut along the YZ plane at the portion where it joins the beams 3, 3 extending in the Y direction, forming the lower beam joint portion 46, and the outer peripheral edge portion 421 is cut along the YZ plane at the portion where it joins the beams 3, 3 extending in the X direction, forming the lower beam joint portion 46. As described above, the upper beam joint portion 45 and the lower beam joint portion 46 are formed in a total of four positions in the X direction and the Y direction, respectively. With the above-mentioned configuration, the beam 3 and the diaphragm member 4 can be reliably joined, and the diaphragm member 4 can be framed in a configuration that is efficient with respect to the surrounding structures. In addition, the details of the beam-column joint 11 can be simplified for complex structures such as diagonal beams. In addition, the beam-column joint 11 can be formed in a configuration that improves the joinability between the flange 33 and the outer peripheral edge portions 411, 421.

[0034] Next, an analysis of the rigidity of the diaphragm member of the joint structure between a column and a beam according to this embodiment will be described. In the analysis model of this embodiment, the beams 3, 3 on both sides in the Y direction are ignored. The scale is 50%, and the beam widths W1, W2 (see FIG. 3) of the upper flange 31 and the lower flange 32 of the beams 3, 3 (SN490B material) on both sides in the X direction are 170 mm, the flange thickness T1 is 25 mm, and the web thickness is 18 mm. The upper diaphragm portion 41 and the lower diaphragm portion 42 (SN490B material) have an outer diameter D1 of 600 mm, an inner diameter D2 of 430 mm, and a diaphragm thickness T2 of 25 mm, and the upper beam joint portion 45 and the lower beam joint portion 46 are cut along the YZ plane with a size that provides horizontal portions of 15 mm each at the beam ends. The width Wd of the upper reinforcing member 432 and the lower reinforcing member 442 is 10 mm. In order to compare with the element experiment test results of 50% scale, the actual yield strength value of the test specimen of 350.8 N / mm 2 was used, but the Young's modulus was the general value of 2.05×10 5 N / mm 2 In addition, the concrete 23 filled inside the steel pipe 21 and the joint steel pipe 24 was ignored, and a hollow condition was used.

[0035] As comparative examples of the above analysis model, Comparative Example 1 is a joint structure between a column and a beam in which the upper reinforcing part 43 and the lower reinforcing part 44 are not provided (unreinforced), and Comparative Example 2 is a joint structure between a column and a beam in which the upper reinforcing part 43 and the lower reinforcing part 44 have an external shape (cross-penetrating reinforcement) in which the outer shape is a cross shape (reinforcement width length 20 mm) passing through the X-axis and the Y-axis in a plan view in the Z-direction as shown in Fig. 4. In Comparative Example 1 and Comparative Example 2, the beams 3, 3 on both sides in the Y-direction and the concrete 23 filled inside the steel pipe 21 and the joint steel pipe 24 are ignored, as in the analysis model of this embodiment. For the above analytical model and comparative example, forced displacements of the same magnitude are applied in opposite directions to the beams 3, 3 on both sides in the X direction. The analysis is performed by planar FEM analysis, and a relationship diagram between the applied load and the amount of displacement as the analysis result is shown in Fig. 5 (in Fig. 5, the analytical model of this embodiment is referred to as "Example").

[0036] 5, the analysis model of this embodiment reduced the stress intensity at the critical section when subjected to the same deformation, compared to Comparative Example 2. Also, when comparing the load at a displacement of about 7 mm, the analysis model of this embodiment had a reaction force that was about 1.8 times that of Comparative Example 1, and Comparative Example 2 had a reaction force that was about 2.0 times that of Comparative Example 1, and it is found that the analysis model of this embodiment has a reinforcing effect (increased tensile rigidity) due to the provision of the reinforcing part.

[0037] Although the embodiment of the joint structure 1 between a column and a beam according to the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the present invention. For example, in the above embodiment, the diaphragm member 4 is formed in an annular shape with an outer shape that is substantially circular when viewed from above in the Z direction, but it may be formed in an annular rectangular shape, an annular polygonal shape, or the like.

[0038] In the above embodiment, the beams 3 are joined to the diaphragm member 4 from four directions on both the X and Y directions, and the upper reinforcing portion 43 is bridged to the inner peripheral edge portion 412 at four positions that respectively face the four positions on the outer peripheral edge portion 411 where the beams 3 are joined. Similarly, the lower reinforcing portion 44 is bridged to the inner peripheral edge portion 422 at four positions that respectively face the four positions on the outer peripheral edge portion 421 where the beams 3 are joined. Regarding the above configuration, the joint structure 1 between the column and the beam is not limited to this embodiment. For example, the position where the beam 3 is joined and the position where the upper reinforcing part 43 and the lower reinforcing part 44 are connected to the upper diaphragm part 41 and the lower diaphragm part 42 may be set appropriately, and the beam 3 such as the column 2 (corner column) at the corner of the structure may be joined from two or three directions. [Explanation of symbols]

[0039] 1. Column and beam joint structure 2 Pillars 2a Pillar core 3 beams 4 Diaphragm member 4a Outer diaphragm part 4b Reinforcement 11 Column and beam joints 21 Steel pipe 22 Reinforcement 23 Concrete 33 Flange 34 Web 411 Upper diaphragm outer edge 412 Upper diaphragm inner edge 421 Lower diaphragm outer edge 422 Lower diaphragm inner edge

Claims

1. A joint structure between a column of a concrete-filled steel pipe structure, in which concrete is filled inside the steel pipe, and a beam of a steel frame structure, The beam includes a flange and a web. A diaphragm member is provided at a joint between the column and the beam, The diaphragm member is An outer diaphragm portion having a ring shape in a plan view and protruding outward from the outer peripheral surface of the steel pipe and having the flange joined to its outer peripheral edge portion; a reinforcing portion provided on an inner peripheral edge of the outer diaphragm portion and extending radially; Equipped with The reinforcing portion is provided on a line connecting a plan view end portion of a joint between the flange and the outer peripheral portion at the inner peripheral portion and a column core of the column, Joint structure between pillars and beams.

2. The outer diaphragm portion has a circular outer shape in a plan view. A column-to-beam joint structure according to claim 1.

3. The shapes of the joint surfaces of the outer peripheral edge portion and the flange are substantially the same. A column-to-beam joint structure according to claim 1 or 2.

4. The reinforcing portion is bridged on the inner peripheral edge portion at a position closely facing a joining position where the beam is joined to the outer peripheral edge portion in a beam axis direction of the beam. A joint structure between a column and a beam according to any one of claims 1 to 3.

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