Structure of column-beam joint part

Abstract

To provide a structure of a column-beam joint part which can increase a bearing force of the column-beam joint part with a relatively simple structure and has excellent economical efficiency, workability and structural performance, in the column-beam joint part which is joined so as to penetrate a reinforced-concrete column in such a manner that positions in a height direction of a plurality of steel beams are different from each other.SOLUTION: In a structure of a column-beam joint part which is joined in such a manner that a plurality of steel beams penetrate a reinforced-concrete column, the plurality of steel beams are joined to the reinforced concrete column in such a manner that positions in a height direction are different from each other, and at a portion which penetrates the reinforced-concrete column out of a web of the steel beam, a doubler plate is installed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a structure of a column-beam joint between a reinforced concrete column and a steel beam. [Background technology]

[0002] The structural format of the building is an RCS structure, with columns made of reinforced concrete and beams made of steel. The RCS structure is a rational structure, as it uses reinforced concrete members that are strong against compression for the columns and lightweight steel members that are strong against bending and shear for the beams. In other words, the steel beams allow for long spans, while the reinforced concrete columns economically increase the rigidity of the building and can reliably support the weight of the building. Due to its characteristics, the RCS structure is particularly suitable for buildings with large spans and heavy loads, specifically logistics facilities and stores.

[0003] In RCS structures, the type of structure used for the column-beam joints is key to ensuring the structural performance of the entire building.The most common type of column-beam joint in RCS structures is one in which the end of the steel beam penetrates from one side of the reinforced concrete column to the opposite side (hereinafter referred to as the beam penetration type).

[0004] Here, when there is a step on the floor surface, such as in a logistics warehouse with truck berths on the second floor or above, or when the steel beams joined to the reinforced concrete columns have different beam depths, a step in the height direction will occur between two or more steel beams joined to the reinforced concrete column.

[0005] Patent Document 1 discloses a beam-column joint structure that allows for easy formation of a step between steel beams joined to a reinforced concrete column in an RCS structure. Specifically, a connecting member is provided at the embedded portion where the upper and lower steel beams are embedded in the reinforced concrete column to connect the upper and lower steel beams. The connecting member is joined to the flanges of the upper and lower steel beams so that at least a portion of the connecting member is located between the web of the upper steel beam and the web of the lower steel beam.

[0006] Furthermore, Non-Patent Documents 1 to 3 disclose the structure of beam-column joints in RCS structures when the heights of the top ends of two or more steel beams joined to a reinforced concrete column are different, or when the heights of the top ends of two or more steel beams are the same but the beam depths are different. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-162645 [Non-patent literature]

[0008] [Non-Patent Document 1] Takayuki Sagawa and three others, "Experimental and Analytical Study on the Structural Performance of Frames Composed of Reinforced Concrete Columns and Steel Beams with Stepped Beams," Proceedings of the Japan Concrete Institute, Vol. 37, No. 2, February 2015, pp. 1045-1050 [Non-patent document 2] Naoki Arakane and three others, "Structural Performance of RC Column / S Beam Hybrid Structure: Parts 4-6," Proceedings of the Annual Meeting of the Architectural Institute of Japan, Architectural Institute of Japan, July 2013, pp. 1467-1472 [Non-patent document 3] Masatoshi Harada et al., "Structural Performance of Cross-Shaped Beam-Column Joints in RC Column / S Beam Mixed Structures with Beam Eccentricity and Beam Step Differences, Part 1-2," Proceedings of the Annual Meeting of the Architectural Institute of Japan, Architectural Institute of Japan, July 2018, pp. 1457-1460 Summary of the Invention [Problem to be solved by the invention]

[0009] In the structure of the beam-through type column-beam joint as described above, the following problems arise when trying to increase the strength.

[0010] First, if one attempts to increase the strength of the concrete only within the beam-column joint as a method of increasing the bearing capacity of the beam-column joint, it will be necessary to pour concrete of different strengths into the beam-column joint and the rest of the reinforced concrete column, which is undesirable in terms of workability and structural performance.

[0011] Furthermore, if an attempt is made to increase the thickness of the cover plate that surrounds the concrete in the column-beam joint to enhance the frame effect that restrains the concrete in the column-beam joint, the bending radius when bending the corner of the cover plate becomes larger, which is likely to affect the position of the main reinforcement of the reinforced concrete column. To avoid this, if the corner of the cover plate is formed by welding two steel plates together, this increases the amount of work required to process the cover plate.

[0012] Furthermore, if an attempt is made to increase the shear strength of the web of the steel beam in the beam-column joint panel by increasing the thickness of the web of the steel beam, the cost of the steel beam increases.

[0013] Furthermore, if an attempt is made to increase the strength of a column-beam joint by enlarging the cross section of the column-beam joint, the cross section of the reinforced concrete column must be adjusted to fit the enlarged cross section of the column-beam joint, which means that the cross section of the reinforced concrete column will also become larger.

[0014] The present invention has been made to solve the above-mentioned problems, and aims to provide a column-beam joint structure in which multiple steel beams are joined by penetrating a reinforced concrete column so that they are positioned at different heights, which can increase the strength of the column-beam joint with a relatively simple structure and is excellent in economy, ease of construction, and structural performance. [Means for solving the problem]

[0015] The means for solving the above problems are as follows. [1] A column-beam joint structure in which multiple steel beams are joined so that they penetrate a reinforced concrete column, wherein the multiple steel beams are joined to the reinforced concrete column so that their vertical positions are different from each other, and a doubler plate is installed in the portion of the web of the steel beam that penetrates the reinforced concrete column.

[0016] Here, "different height positions" of multiple steel beams means that the heights of the upper or lower ends of the multiple steel beams or the beam depths of the multiple steel beams are different from each other. [2] A structure of a beam-column joint described in [1], in which at least two of the plurality of steel beams are arranged within the same structural plane, and the lower end of the upper steel beam, which is the steel beam with the higher center of beam depth of the two steel beams, is lower than the upper end of the lower steel beam, which is the steel beam with the lower center of beam depth, and the doubler plate is arranged at a height between the lower end of the upper steel beam and the upper end of the lower steel beam. [3] The column-beam joint structure described in [1], in which the end of a brace is further connected to the column-beam joint between the reinforced concrete column and the steel beam. [4] A column-beam joint structure according to [2], in which the end of a brace is further connected to the column-beam joint between the reinforced concrete column and the steel beam. [5] At least two of the plurality of steel beams are arranged within the same structural plane, and the lower end of the upper steel beam, which is the steel beam with the higher center of beam depth, is higher than the upper end of the lower steel beam, which is the steel beam with the lower center of beam depth, and the lower flange of the upper steel beam and the upper flange of the lower steel beam are joined by a connecting plate. The end of a brace is further joined to the column-beam joint between the reinforced concrete column and the two steel beams, and the doubler plate is arranged in the part of the web of the steel beam that is arranged in the same span as the brace and penetrates the reinforced concrete column. [6] A structure of a beam-column joint described in [5], in which the doubler plate is not placed in the portion of the web of the steel beam that is not located in the same span as the brace, which penetrates the reinforced concrete column. [7] A structure of a beam-column joint described in any one of [1] to [6], wherein holes for filling concrete are provided in the portion of the web of the steel beam that penetrates the reinforced concrete column and in the doubler plate. [Effects of the Invention]

[0017] According to the beam-column joint structure of the present invention, in a beam-column joint in which multiple steel beams penetrate a reinforced concrete column, a doubler plate is installed in the portion of the web of the steel beam that penetrates the reinforced concrete column. This makes it possible to increase the strength of the beam-column joint with a relatively simple structure, and to realize a beam-column joint that is economical, easy to construct, and has excellent structural performance while facilitating the design of the beam-column joint between the reinforced concrete column and the steel beam.

[0018] Furthermore, because doubler plates are installed in the sections of the steel beam webs that penetrate into the reinforced concrete columns, it is possible to drill large holes for concrete filling in the steel beam webs and doubler plates, which improves the filling of concrete into the beam-column joints and makes pouring the concrete easier. [Brief explanation of the drawings]

[0019] [Figure 1] Figures 1(a) and 1(b) are a longitudinal cross-sectional view and a perspective view, respectively, showing the structure of a beam-column joint according to a first embodiment of the present invention, and Figure 1(c) is a perspective view showing the main parts of the structure of the beam-column joint shown in Figures 1(a) and 1(b). [Figure 2] FIG. 2 is a vertical cross-sectional view showing the structure of a beam-to-column joint according to a modified example of the first embodiment of the present invention. [Figure 3] 3(a) and 3(b) are a longitudinal sectional view and a perspective view, respectively, showing the structure of a beam-column joint according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a vertical cross-sectional view showing the structure of a beam-to-column joint according to a modified example of the second embodiment of the present invention. [Figure 5] Figures 5(a) and 5(b) are a longitudinal cross-sectional view and a perspective view, respectively, showing a structure of a beam-column joint according to a third embodiment of the present invention, and Figure 5(c) is a perspective view showing a main part of the structure of the beam-column joint shown in Figures 5(a) and 5(b). [Figure 6] 6(a) and 6(b) are a vertical cross-sectional view and a perspective view, respectively, showing the structure of a beam-column joint according to a fourth embodiment of the present invention. [Figure 7] 7(a) and 7(b) are a vertical cross-sectional view and a perspective view, respectively, showing the structure of a beam-column joint according to a fifth embodiment of the present invention. [Figure 8] Figures 8(a) and 8(b) are longitudinal cross-sectional views showing a beam-column joint according to a sixth embodiment of the present invention, and Figure 8(c) is a perspective view of the beam-column joint shown in Figures 8(a) and 8(b). [Figure 9] 9(a) and 9(b) are side views showing a state in which the end of a brace is joined to a beam-column joint in a beam-column joint structure according to a modified example of the first embodiment of the present invention. [Figure 10] FIG. 10 is a side view showing a state in which an end of a brace is joined to a beam-to-column joint in a beam-to-column joint structure according to a modified example of the second embodiment of the present invention. [Figure 11] 11(a) and 11(b) are side views showing a state in which the end of a brace is joined to a beam-column joint in a beam-column joint structure according to a modified example of the third embodiment of the present invention. [Figure 12] 12(a) and 12(b) are side views showing a state in which an end of a brace is joined to a beam-column joint in a beam-column joint structure according to a modified example of the fourth embodiment of the present invention. [Figure 13] FIG. 13 is a side view showing a state in which an end of a brace is joined to a column-beam joint in a column-beam joint structure according to a fifth embodiment of the present invention. [Figure 14] FIG. 14 is a graph showing the relationship between the effective section modulus cpk of concrete and the ratio of column depth to beam depth CD / BD in the beam-column joint structure of the present invention. [Figure 15] FIG. 15 is a graph showing the relationship between the effective section modulus cpk of concrete and the ratio of column width to beam width Cb / Bb in the beam-column joint structure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the column-beam joint structure of the present invention will be specifically described with reference to the drawings. (First embodiment) 1(a) and 1(b) show a longitudinal cross-sectional view and a perspective view of the structure of a beam-column joint 1A according to a first embodiment of the present invention, and FIG. 1(c) shows a perspective view of the main parts of the structure of the beam-column joint 1A according to the first embodiment of the present invention.

[0021] As shown in Figures 1(a) to 1(c), in the structure of a beam-column joint 1A of the first embodiment, four steel beams 3A, 3C, 3D, and 4 made of H-shaped steel are joined so as to penetrate a reinforced concrete column 2. The structure of beam-column joint 1A of the first embodiment is applied to a beam-penetration type cover plate-type column joint in which four steel beams 3A, 3C, 3D, and 4 are attached in a cross shape to the four sides of the reinforced concrete column 2. As shown in Figures 1(a) and 1(b), the steel beams 3A, 3C, 3D, and 4 that intersect in a cross shape are each arranged so as to completely penetrate the reinforced concrete column 2 from one side to the opposite side.

[0022] In addition, even when steel beams are attached in a T-shape on three sides of the reinforced concrete column 2, or when steel beams are attached in an L-shape on two sides of the reinforced concrete column 2, the steel beams that intersect in a T-shape or L-shape should be installed so that they completely penetrate from one side of the reinforced concrete column 2 to the opposite side.

[0023] The four steel beams 3A, 3C, 3D, and 4 are joined to the reinforced concrete column 2 so that their positions in the height direction are different from each other. Specifically, in the main direction, two steel beams 3A and 4 are arranged on the same structural plane and joined to the reinforced concrete column 2. In addition, in the perpendicular direction, two steel beams 3C and 3D are arranged on the same structural plane and joined to the reinforced concrete column 2. The beam depths of the four steel beams 3A, 3C, 3D, and 4 are equal to each other, but the heights of the upper ends of the steel beams 3A, 3C, and 3D are different from the height of the upper end of the steel beam 4, and the lower ends of the upper three steel beams 3A, 3C, and 3D are lower than the upper end of the steel beam 4 in the lower row. In other words, the beam depth of the steel beam 3A in the main direction among the upper steel beams 3A, 3C, and 3D is: B D1 (mm), beam depth of lower steel beam 4: B D2 (mm), Center distance between upper steel beam 3A and lower steel beam 4: B If H (mm), the step ratio of steel beams 3A and 4 is 2 B H / ( B D1+ B D2)<1.

[0024] As shown in Figures 1(b) and 1(c), the two steel beams 3C, 3D joined to both sides of the reinforced concrete column 2 in the orthogonal direction are actually composed of a single H-shaped steel that is arranged to penetrate the reinforced concrete column 2. Of the steel beams 3A, 4 arranged in the main direction, the upper steel beam 3A is arranged to penetrate the H-shaped steel that constitutes the two orthogonal steel beams 3C, 3D, and is welded to both sides of this H-shaped steel.

[0025] 1(a) and 1(c), on both sides of the portion where the lower steel beam 4 of the steel beams 3A, 4 arranged in the main direction penetrates the reinforced concrete column 2, anchoring portions 44 for holding cover plates 22 (described later) are arranged so as to penetrate the H-shaped steel that constitutes the lower steel beam 4 and are welded to both sides of this H-shaped steel. The anchoring portions 44 are made of T-shaped steel with a beam depth equal to the difference in height between the bottom end of the upper steel beam 3A and the bottom end of the lower steel beam 4.

[0026] In the structure of beam-column joint 1A of the first embodiment, as shown in Figures 1(a) and 1(c), within beam-column joint 1A, webs 31, 41 of steel beams 3A, 4 in the main direction are reinforced by doubler plates 7. Specifically, the entire length of the outer periphery of doubler plates 7 is fixed to webs 31, 41 of steel beams 3A, 4 by fillet welding or the like. Although not shown in the figures, webs 31 of steel beams 3C, 3D in the orthogonal direction are also reinforced by doubler plates 7 in the beam-column joint 1A.

[0027] In this way, in the structure of the beam-column joint 1A of the first embodiment, doubler plates 7 are installed and reinforced on the webs 31, 41 of the steel beams 3A, 3C, 3D, and 4 within the beam-column joint 1A, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joint 1A.

[0028] 1(a) and 1(c), in the structure of beam-column joint 1A of the first embodiment, concrete filling holes 31h, 41h, and 7h are provided in the portions of webs 31 and 41 of steel beams 3A and 4 in the main direction that penetrate into reinforced concrete column 2 and in doubler plates 7 fixed to these portions. Although not shown, similarly, concrete filling holes are provided in the portions of webs 31 of steel beams 3C and 3D in the orthogonal direction that penetrate into reinforced concrete column 2 and in doubler plates fixed to these portions.

[0029] In the structure of beam-column joint 1A of the first embodiment, the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 in beam-column joint 1A between the reinforced concrete column 2 and the steel beams 3A, 3C, 3D, 4 are reinforced by the doubler plate 7, so it is possible to open large concrete filling holes 31h, 41h, 7h in the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 and the doubler plate 7 in beam-column joint 1A. This improves the filling of concrete into beam-column joint 1A and makes pouring the concrete easier.

[0030] 1(a) to 1(c), in the structure of the beam-column joint 1A of the first embodiment, a cover plate 22 made of a steel plate is provided to surround the concrete (not shown) poured continuously from the reinforced concrete columns 2 above and below the beam-column joint 1A. The cover plate 22 is provided to completely cover the concrete in the beam-column joint 1 up to the surface of the webs 31 and 41 of the steel beams 3A, 3C, 3D, and 4, within the height range between the upper flanges 32 and 42 and the lower flanges 33 and 43 of the steel beams 3A, 3C, 3D, and 4. The side edges of the cover plate 22 are fixed by welding to the webs 31 and 41, the upper flanges 32 and 42, and the lower flanges 33 and 43 of the steel beams 3A, 3C, 3D, and 4, as well as to the web and lower flange of the T-shaped steel that constitutes the anchorage portion 44 of the steel beam 4. As described above, even in the areas where the steel beams 3A, 3C, 3D, and 4 that penetrate the reinforced concrete column 2 protrude onto the opposite side of the reinforced concrete column 2, the cover plates 22 are fixed by welding to the webs 31, 41, upper flanges 32, 42, and lower flanges 33, 43 of the steel beams 3A, 3C, 3D, and 4.

[0031] Width of cover plate 22 h b (mm) and thickness h t (mm) is h b / h t ≤ 217 and h It is preferable to satisfy the relationship t ≥ 6. This can suppress buckling of the cover plate 22 and provide a sufficient frame effect of restraining the concrete by the cover plate 22, thereby increasing the strength of the beam-column joint 1A.

[0032] Here, the width of the blocking plate 22 hb (mm) refers to the total horizontal width of each of the cover plates 22 provided between horizontally adjacent steel beams 3A, 4 among the multiple steel beams 3A, 4 attached to the reinforced concrete column 2, and corresponds to the total width of the beam-column joint 1A as shown in Figure 1(b). For example, in the structure of the beam-column joint 1A shown in Figures 1(a) to 1(c), four cover plates 22 bent into an L shape are provided to cover the concrete (not shown) between the adjacent steel beams 3A, 4. h b (mm) refers to the overall width of each of these blocking plates 22 before bending.

[0033] Alternatively, in the structure of beam-column joint 1A shown in FIGS. 1(a) to 1(c), bearing plates (not shown) for supporting the concrete in beam-column joint 1A may be provided in the areas surrounded by the webs 31, upper flanges 32, and lower flanges 33 of steel beams 3A, 3C, and 3D, and the areas surrounded by the webs 41, upper flanges 42, and lower flanges 43 of steel beam 4. The bearing plates are preferably steel plates having a thickness equal to or greater than the thickness of the webs 31 and 41 of steel beams 3A and 4, and are fixed by welding to the webs 31, upper flanges 32, and lower flanges 33 of steel beams 3A, 3C, and 3D, or the webs 41, upper flanges 42, and lower flanges 43 of steel beam 4. Cover plates 22 are provided to surround the portions of the concrete (not shown) poured continuously from the reinforced concrete columns 2 above and below beam-column joint 1A within beam-column joint 1A that are not covered by the bearing plates. The bearing plates and cover plates 22 are installed in the height range between the upper flanges 32 of the steel beams 3A, 3C, and 3D and the lower flange 43 of the steel beam 4, so as to completely cover the concrete in the beam-to-column joint 1A up to the surface level of the webs 31 of the steel beams 3A, 3C, and 3D and the web 41 of the steel beam 4. The cover plates 22 are installed so as to be continuous with the bearing plates, and are fixed to the bearing plates by welding or bolting.

[0034] In this way, the bearing plate enhances the bearing effect of the concrete, allowing the concrete in the beam-column joint 1A to fully exert its shear strength. In addition, the frame effect of the bearing plate increases the shear strength borne by the webs 31, 41 and doubler plate 7 of the steel beams 3A, 3C, 3D, 4 in the beam-column joint 1A.

[0035] According to the structure of the beam-column joint 1A of the first embodiment, the webs 31, 41 of the steel beams 3A, 3C, 3D, and 4 in the beam-column joint 1A between the reinforced concrete column 2 and the steel beams 3A, 3C, 3D, and 4 are reinforced by the doubler plate 7, thereby increasing the strength of the beam-column joint 1A with a relatively simple structure. Furthermore, the structure of the beam-column joint 1A of the first embodiment allows the shear strength of the doubler plate 7 to be added to the shear strength of the entire beam-column joint 1A, making it easier to design the beam-column joint 1A. Thus, the structure of the beam-column joint 1A of the first embodiment simplifies the design of the beam-column joint 1A between the reinforced concrete column 2 and the steel beams 3A, 3C, 3D, and 4, while providing a beam-column joint 1A that is economical, easy to construct, and has excellent structural performance.

[0036] Unlike methods for increasing the bearing capacity of a column-beam joint by increasing the strength of the concrete only within the column-beam joint, the structure of column-beam joint 1A of the first embodiment allows concrete of the same strength to be poured integrally within column-beam joint 1A and the rest of reinforced concrete column 2. For this reason, the structure of column-beam joint 1A of the first embodiment is excellent in terms of workability and structural performance.

[0037] Furthermore, by reinforcing the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 in the beam-column joint 1A with the doubler plate 7, the bearing strength of the beam-column joint 1A can be increased without increasing the thickness of the cover plate 22. This eliminates the need to increase the bending radius according to the plate thickness when bending the corners of the cover plate, and does not affect the position of the main reinforcement 21 of the reinforced concrete column 2.

[0038] Furthermore, in the structure of the beam-to-column joint 1A of the first embodiment, instead of increasing the thickness of the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 as a whole, the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 are reinforced by the doubler plates 7 only within the beam-to-column joint 1A. Therefore, the cost required for the steel beams 3A, 4 does not increase.

[0039] FIG. 2 shows a longitudinal cross-sectional view of the structure of a beam-column joint 1A′ according to a modified example of the first embodiment of the present invention, together with the distribution of shear force generated in the reinforced concrete column 2 in the horizontal direction.

[0040] As shown in the shear force distribution on the right side of FIG. 2, in the structure of the beam-column joint 1A of the first embodiment, a large shear force is generated in the region where the webs 31, 41 of the two steel beams 3A, 4 arranged in the main direction overlap in the height direction, i.e., in the height range between the lower end of the upper steel beam 3A and the upper end of the lower steel beam 4. Therefore, in the structure of the beam-column joint 1A' of the modified first embodiment, the doubler plate 7 is provided only in the area where stress is concentrated. That is, in the structure of the beam-column joint 1A' of the modified first embodiment, as shown in FIG. 2, the doubler plate 7 is disposed only in the height range between the lower end of the upper steel beam 3A and the upper end of the lower steel beam 4. In other respects, the structure of the beam-column joint 1A' of the modified first embodiment is configured similarly to the structure of the beam-column joint 1A of the first embodiment.

[0041] In the structure of the beam-column joint 1A' of the modified example of the first embodiment, doubler plates 7 are provided only in areas where stress is concentrated, resulting in a more rational structure and making it even easier to design the beam-column joint.

[0042] The structure of the beam-column joint 1A of the first embodiment and the structure of the beam-column joint 1A' of the modified example of the first embodiment are B D2 / B D1( B D1≧ BIt is preferable to apply this when D2) is within the range of 0.5 to 1.0. In addition, among the upper steel beams 3A, 3C, and 3D, the beam depth of the steel beams 3C and 3D in the orthogonal direction is: B If D3 (mm), the beam depth ratio of the main direction steel beam 3A and the perpendicular direction steel beams 3C and 3D is B D3 / B It is preferably applied when D1 is within the range of 0.5 to 1.0. (Second embodiment) 3(a) and 3(b) show a vertical cross-sectional view and a perspective view of the structure of a beam-to-column joint 1B according to a second embodiment of the present invention.

[0043] As shown in Figures 3(a) and 3(b), in the structure of the beam-column joint 1B of the second embodiment, four steel beams 3B-3D, 5A made of H-shaped steel are joined to a reinforced concrete column 2 so that they penetrate the column. The four steel beams 3B-3D, 5A are joined to the reinforced concrete column 2 so that their height positions are different from each other. Specifically, in the main direction, two steel beams 3B, 5A are arranged on the same structural plane and joined to the reinforced concrete column 2, and in the orthogonal direction, two steel beams 3C, 3D are arranged on the same structural plane and joined to the reinforced concrete column 2. The heights of the upper ends of the four steel beams 3B-3D, 5A are equal to each other, but the beam depth of steel beam 5A is smaller than the beam depth of steel beams 3B-3D, and the height of the lower ends of steel beams 3B-3D is lower than the height of the lower end of steel beam 5A. In other words, the beam depth of steel beam 3B in the main direction: B D1 (mm), beam depth of steel beam 5A: B If D2 (mm), B D1> B It's D2.

[0044] As shown in Figure 3(b), the two steel beams 3C and 3D connected to both sides of the reinforced concrete column 2 in the orthogonal direction are actually composed of a single H-shaped steel that is arranged to penetrate the reinforced concrete column 2. Steel beams 3B and 5A arranged in the main direction are welded to both sides of the H-shaped steel that constitutes the two orthogonal steel beams 3C and 3D.

[0045] In the structure of beam-to-column joint 1B of the second embodiment, as shown in Fig. 3(a), within beam-to-column joint 1B, webs 31, 51 of steel beams 3B, 5A in the main direction are reinforced by doubler plates 7. Specifically, the entire outer periphery of doubler plate 7 is fixed to webs 31, 51 of steel beams 3B, 5A by fillet welding or the like. Although not shown in the figure, webs 31 of steel beams 3C, 3D in the orthogonal direction are also reinforced by doubler plates in the same manner within beam-to-column joint 1B.

[0046] In this way, in the structure of the column-beam joint 1B of the second embodiment, doubler plates 7 are installed and reinforced on the webs 31, 51 of the steel beams 3B to 3D, 5A within the column-beam joint 1B, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire column-beam joint 1B.

[0047] 3(a), in the structure of the beam-column joint 1B of the second embodiment, concrete filling holes 31h, 51h, 7h are provided in the portions of the webs 31, 51 of the steel beams 3B, 5A in the main direction that penetrate into the reinforced concrete column 2 and in the doubler plate 7 fixed to these portions. Although not shown in the figure, similarly, concrete filling holes are provided in the portions of the webs 31 of the steel beams 3C, 3D in the orthogonal direction that penetrate into the reinforced concrete column 2 and in the doubler plate fixed to these portions.

[0048] In the structure of beam-column joint 1B of the second embodiment, the webs 31, 51 of steel beams 3B-3D, 5A in beam-column joint 1B between reinforced concrete column 2 and steel beams 3B-3D, 5A are reinforced by doubler plate 7, so it is possible to open large concrete filling holes 31h, 51h, 7h in the webs 31, 51 of steel beams 3B-3D, 5A in beam-column joint 1B and doubler plate 7. This improves the filling of concrete into beam-column joint 1B and makes pouring concrete easier.

[0049] In other respects, the structure of the beam-column joint 1B of the second embodiment is configured similarly to the structure of the beam-column joint 1A of the first embodiment.

[0050] According to the structure of the beam-column joint 1B of the second embodiment, the same effects as those of the structure of the beam-column joint 1A of the first embodiment can be obtained.

[0051] FIG. 4 shows a longitudinal cross-sectional view of the structure of a beam-column joint 1B' according to a modified example of the second embodiment of the present invention, together with the distribution of shear force generated in the reinforced concrete column 2 in the horizontal direction.

[0052] As shown in the shear force distribution on the right side of Figure 4, in the structure of the beam-column joint 1B of the second embodiment, a large shear force is generated in the region where the webs 31, 51 of the two steel beams 3B, 5A arranged in the main direction overlap in the height direction, i.e., in the height range between the upper and lower ends of the steel beam 5A. Therefore, in the structure of the beam-column joint 1B' of the modified second embodiment, the doubler plate 7 is provided only in the area where stress is concentrated. That is, in the structure of the beam-column joint 1B' of the modified second embodiment, as shown in Figure 4, the doubler plate 7 is disposed only in the height range between the upper and lower ends of the steel beam 5A. In other respects, the structure of the beam-column joint 1B' of the modified second embodiment is configured similarly to the structure of the beam-column joint 1B of the second embodiment.

[0053] In the structure of the beam-column joint 1B' of the modified example of the second embodiment, doubler plates 7 are provided only in areas where stress is concentrated, resulting in a more rational structure and making it even easier to design the beam-column joint. (Third embodiment) Figures 5(a) and 5(b) show a longitudinal cross-sectional view and a perspective view of the structure of a beam-column joint 1C according to a third embodiment of the present invention. Figure 5(c) shows a perspective view of the main parts of the structure of a beam-column joint 1C according to the third embodiment of the present invention. Figure 5(a) also shows the distribution of shear force generated horizontally in a reinforced concrete column 2.

[0054] As shown in FIGS. 5(a) and 5(b), in the structure of a beam-column joint 1C of the third embodiment, four steel beams 3A, 3C, 3D, and 4 made of H-shaped steel are joined to a reinforced concrete column 2 so that they penetrate the column. The four steel beams 3A, 3C, 3D, and 4 are joined to the reinforced concrete column 2 so that their height positions are different from each other. Specifically, in the main direction, two steel beams 3A and 4 are arranged on the same structural plane and joined to the reinforced concrete column 2, and in the orthogonal direction, two steel beams 3C and 3D are arranged on the same structural plane and joined to the reinforced concrete column 2. The four steel beams 3A, 3C, 3D, and 4 have the same beam depth, but the height of the upper ends of the steel beams 3A, 3C, and 3D is different from the height of the upper end of the steel beam 4, so that the lower ends of the upper three steel beams 3A, 3C, and 3D are higher than the upper end of the steel beam 4 in the lower row. That is, the beam depth of the main direction steel beam 3A among the upper steel beams 3A, 3C, and 3D is: B D1 (mm), beam depth of lower steel beam 4: B D2 (mm), Center distance between upper steel beam 3A and lower steel beam 4: B If H (mm), the step ratio of steel beams 3A and 4 is 2 B H / ( B D1+ B D2)>1.

[0055] The bottom flange 33 of one steel beam 3A of the three upper steel beams 3A, 3C, and 3D is joined to the top flange 42 of the lower steel beam 4 by a tie plate 6. The tie plate 6 is arranged in the same plane as the webs 31, 41 of the upper steel beam 3A and the lower steel beam 4 that are joined by this tie plate 6.

[0056] As shown in Figures 5(b) and 5(c), the two steel beams 3C, 3D joined to both sides of the reinforced concrete column 2 in the orthogonal direction are actually composed of a single H-shaped steel that is arranged to penetrate the reinforced concrete column 2. Of the steel beams 3A, 4 arranged in the main direction, the upper steel beam 3A is arranged to penetrate the H-shaped steel that constitutes the two orthogonal steel beams 3C, 3D, and is welded to both sides of this H-shaped steel.

[0057] 5(a) and 5(c), on both sides of the portion where the lower steel beam 4 of the steel beams 3A, 4 arranged in the main direction penetrates the reinforced concrete column 2, anchoring portions 44 for holding the cover plates 22 are arranged so as to penetrate the H-shaped steel that constitutes the lower steel beam 4, and are welded to both sides of this H-shaped steel and to connecting plates 6 (described later) that are arranged in the same plane as the webs of the steel beams 3C, 3D. The anchoring portions 44 are made of H-shaped steel that has the same beam depth as the steel beam 4.

[0058] The bottom flanges 33 of two of the three upper steel beams 3A, 3C, and 3D that are arranged in an orthogonal direction are joined to the upper flanges of the H-shaped steel that constitutes the anchoring portion 44 by tie plates 6. The tie plates 6 are arranged in the same plane as the webs 31 of the steel beams 3C and 3D that are joined by these tie plates 6 and the webs of the steel beams that constitute the anchoring portion 44.

[0059] In the structure of a beam-column joint 1C of the third embodiment, as shown in Figures 5(a) and 5(c), in the beam-column joint 1C, the webs 31, 41 of the steel beams 3A, 4 in the main direction are reinforced by doubler plates 7. Specifically, the entire length of the outer periphery of the doubler plates 7 is fixed to the webs 31, 41 of the steel beams 3A, 4 by fillet welding or the like. Although not shown in the figures, in the beam-column joint 1C, the webs 31 of the steel beams 3C, 3D in the orthogonal direction are also reinforced by doubler plates in a similar manner.

[0060] In this way, in the structure of the beam-column joint 1C of the third embodiment, doubler plates 7 are installed and reinforced on the webs 31, 41 of the steel beams 3A, 3C, 3D, and 4 within the beam-column joint 1C, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joint 1C.

[0061] In the structure of beam-column joint 1C of the third embodiment, as shown in Fig. 5(a), concrete filling holes 31h, 41h, 7h are provided in the portions of webs 31, 41 of steel beams 3A, 4 in the main direction that penetrate into reinforced concrete column 2 and in doubler plates 7 fixed to these portions. Although not shown, similarly, concrete filling holes are provided in the portions of webs 31 of steel beams 3C, 3D in the orthogonal direction that penetrate into reinforced concrete column 2 and in doubler plates fixed to these portions.

[0062] In the structure of beam-column joint 1C of the third embodiment, the webs 31, 41 of steel beams 3A, 3C, 3D, 4 in beam-column joint 1C between reinforced concrete column 2 and steel beams 3A, 3C, 3D, 4 are reinforced by doubler plate 7, so it is possible to open large concrete filling holes 31h, 41h, 7h in the webs 31, 41 of steel beams 3A, 3C, 3D, 4 and doubler plate 7 in beam-column joint 1C. This improves the filling of concrete in beam-column joint 1C and makes pouring the concrete easier.

[0063] Furthermore, in the structure of the beam-column joint 1C of the third embodiment, as shown in FIG. 5(a), the tie plate 6 connecting the steel beam 3A in the main direction of the upper three steel beams 3A, 3C, and 3D to the lower steel beam 4 also has a concrete filling hole 6h. As shown by the shear force distribution shown on the right side of FIG. 5(a), in the structure of the beam-column joint 1C of the third embodiment, the shear force acting on the tie plate 6 is smaller than the shear force acting on the webs 31 and 41 of the steel beams 3A and 4. Therefore, the diameter of the hole 6h in the tie plate 6 can be larger than the diameter of the holes 31h and 41h in the webs 31 and 41 of the steel beams 3A and 4. This further improves the filling of concrete into the beam-column joint 1C, facilitating concrete pouring.

[0064] In other respects, the structure of the beam-column joint 1C of the third embodiment is configured similarly to the structure of the beam-column joint 1A of the first embodiment.

[0065] The structure of the column-beam joint 1C of the third embodiment is a step ratio of 2 between the steel beams 3A, 3C, 3D, and 4. B H / ( B D1+ B It is preferable to apply when D2)≦1.25.

[0066] According to the structure of the beam-to-column joint 1C of the third embodiment, the same effects as those of the structure of the beam-to-column joint 1A of the first embodiment can be obtained. (Fourth embodiment) FIG. 6(a) and FIG. 6(b) show a vertical cross-sectional view and a perspective view of the structure of a beam-column joint 1D according to a fourth embodiment of the present invention.

[0067] As shown in FIGS. 6(a) and 6(b), in the structure of a beam-column joint 1D of the fourth embodiment, four steel beams 3A, 3C, 3D, and 4 made of H-shaped steel are joined to a reinforced concrete column 2 so that they penetrate the column. The four steel beams 3A, 3C, 3D, and 4 are joined to the reinforced concrete column 2 so that their height positions are different from each other. Specifically, in the main direction, two steel beams 3A and 4 are arranged on the same structural plane and joined to the reinforced concrete column 2, and in the orthogonal direction, two steel beams 3C and 3D are arranged on the same structural plane and joined to the reinforced concrete column 2. The four steel beams 3A, 3C, 3D, and 4 have the same beam depth, but the height of the upper end of the steel beams 3A, 3C, and 3D is different from the height of the upper end of the steel beam 4. The bottom flanges 33 of the upper three steel beams 3A, 3C, and 3D are at the same height as the top flange 42 of the lower steel beam 4. That is, the beam depth of the main direction steel beam 3A among the upper steel beams 3A, 3C, and 3D is: B D1 (mm), beam depth of lower steel beam 4: B D2 (mm), Center distance between upper steel beam 3A and lower steel beam 4: B If H (mm), the step ratio of steel beams 3A and 4 is 2 B H / ( B D1+ B D2)=1.

[0068] As shown in Figure 6(b), the two steel beams 3C, 3D joined to both sides of the reinforced concrete column 2 in the orthogonal direction are actually composed of a single H-shaped steel that is arranged to penetrate the reinforced concrete column 2. Of the steel beams 3A, 4 arranged in the main direction, the upper steel beam 3A is arranged to penetrate the H-shaped steel that constitutes the two orthogonal steel beams 3C, 3D, and is welded to both sides of this H-shaped steel.

[0069] Furthermore, on both sides of the portion where the lower steel beam 4 of the steel beams 3A, 4 arranged in the main direction penetrates the reinforced concrete column 2, anchoring portions 44 for holding the cover plates 22 are arranged so as to penetrate the H-shaped steel that constitutes the lower steel beam 4 and are welded to both sides of this H-shaped steel. The anchoring portions 44 are made of T-shaped steel that has the same beam depth as the steel beam 4.

[0070] In the structure of a beam-column joint 1D of the fourth embodiment, as shown in Fig. 6(a), within the beam-column joint 1D, the webs 31, 41 of the steel beams 3A, 4 in the main direction are reinforced by a doubler plate 7. Specifically, the entire length of the outer periphery of the doubler plate 7 is fixed to the webs 31, 41 of the steel beams 3A, 4 by fillet welding or the like. Although not shown in the figure, in the beam-column joint 1D, the webs 31 of the steel beams 3C, 3D in the orthogonal direction are also reinforced by a doubler plate in the same way.

[0071] In this way, in the structure of the beam-column joint 1D of the fourth embodiment, doubler plates 7 are installed and reinforced on the webs 31, 41 of the steel beams 3A, 3C, 3D, and 4 within the beam-column joint 1D, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joint 1D.

[0072] In the structure of the beam-column joint 1D of the fourth embodiment, as shown in Fig. 6(a), concrete filling holes 31h, 41h, 7h are provided in the portions of the webs 31, 41 of the steel beams 3A, 4 in the main direction that penetrate into the reinforced concrete column 2 and in the doubler plate 7 fixed to these portions. Although not shown in the figure, similarly, concrete filling holes are provided in the portions of the webs 31 of the steel beams 3C, 3D in the orthogonal direction that penetrate into the reinforced concrete column 2 and in the doubler plate fixed to these portions.

[0073] In the structure of the beam-column joint 1D of the fourth embodiment, the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 in the beam-column joint 1C between the reinforced concrete column 2 and the steel beams 3A, 3C, 3D, 4 are reinforced by the doubler plate 7, so it is possible to open large concrete filling holes 31h, 41h, 7h in the webs 31, 41 of the steel beams 3A, 3C, 3D, 4 and the doubler plate 7 in the beam-column joint 1D. This improves the filling of concrete in the beam-column joint 1D and makes pouring the concrete easier.

[0074] According to the structure of the beam-column joint 1D of the fourth embodiment, the same effects as those of the structure of the beam-column joint 1A of the first embodiment can be obtained. (Fifth embodiment) 7(a) and 7(b) show a vertical cross-sectional view and a perspective view of the structure of a beam-column joint 1E according to a fifth embodiment of the present invention.

[0075] As shown in FIGS. 7(a) and 7(b), in the structure of a beam-column joint 1E of the fifth embodiment, four steel beams 3A, 3B, 5C, and 5D made of H-shaped steel are joined to a reinforced concrete column 2 so that they penetrate the column. The four steel beams 3A, 3B, 5C, and 5D are joined to the reinforced concrete column 2 so that their height positions are different from each other. Specifically, in the main direction, two steel beams 3A and 3B are arranged on the same structural plane and joined to the reinforced concrete column 2, and in the orthogonal direction, two steel beams 5C and 5D are arranged on the same structural plane and joined to the reinforced concrete column 2. The heights of the upper ends of the four steel beams 3A, 3B, 5C, and 5D are equal to each other, but the beam depths of the steel beams 5C and 5D are smaller than the beam depths of the steel beams 3A and 3B, and the height of the lower end of the steel beam 3A is lower than the height of the lower ends of the steel beams 5C and 5D. That is, the beam depth of steel beams 3A and 3B in the main direction: B D1 (mm), Beam depth of steel beams 5C and 5D in the orthogonal direction: B If D3 (mm), B D1> B It's D3.

[0076] As shown in Figure 7(b), two steel beams 5C and 5D joined to both sides of the reinforced concrete column 2 in the orthogonal direction are actually composed of a single H-shaped steel that is arranged to penetrate the reinforced concrete column 2. Steel beams 3A and 3B arranged in the main direction are welded to both sides of the H-shaped steel that constitutes the two steel beams 5C and 5D.

[0077] Furthermore, on both sides of the portions where the steel beams 3A, 3B arranged in the main direction penetrate the reinforced concrete column 2, anchoring portions 34 for holding the cover plates 22 are arranged so as to penetrate the H-shaped steel that constitutes the steel beams 3A, 3B in the main direction, and are welded to both sides of these H-shaped steel and to the bottom flanges 53 of the steel beams 5C, 5D in the orthogonal direction. The anchoring portions 34 are made of steel plates with a height that is the difference between the beam depth of the steel beams 3A, 3B in the main direction and the beam depth of the steel beams 5C, 5D in the orthogonal direction.

[0078] In the structure of a beam-to-column joint 1E of the fifth embodiment, as shown in Fig. 7(a), within the beam-to-column joint 1E, the webs 31 of the steel beams 3A and 3B in the main direction are reinforced by doubler plates 7. Specifically, the entire outer periphery of the doubler plates 7 is fixed to the webs 31 of the steel beams 3A and 3B by fillet welding or the like. Although not shown in the figure, in the beam-to-column joint 1E, the webs 51 of the steel beams 5C and 5D in the orthogonal direction are also reinforced by doubler plates in a similar manner.

[0079] In this way, in the structure of the beam-column joint 1E of the fifth embodiment, doubler plates 7 are installed and reinforced on the webs 31, 51 of the steel beams 3A, 3B, 5C, and 5D within the beam-column joint 1E, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joint 1E.

[0080] In the structure of the beam-column joint 1E of the fifth embodiment, as shown in Fig. 7(a), holes 31h, 7h for filling concrete are provided in the portions of the webs 31 of the steel beams 3A, 3B in the main direction that penetrate into the reinforced concrete column 2 and in the doubler plate 7 fixed to these portions. Although not shown, similar holes for filling concrete are also provided in the portions of the webs 51 of the steel beams 5C, 5D in the orthogonal direction that penetrate into the reinforced concrete column 2 and in the doubler plate fixed to these portions.

[0081] In the structure of beam-column joint 1E of the fifth embodiment, the webs 31, 51 of steel beams 3A, 3B, 5C, 5D in beam-column joint 1E between reinforced concrete column 2 and steel beams 3A, 3B, 5C, 5D are reinforced by doubler plate 7, so it is possible to open large concrete filling holes 31h, 7h in the webs 31, 51 of steel beams 3A, 3B, 5C, 5D in beam-column joint 1E and in doubler plate 7. This improves the filling of concrete into beam-column joint 1E, making it easier to pour the concrete.

[0082] In other respects, the structure of the beam-column joint 1E of the fifth embodiment is configured similarly to the structure of the beam-column joint 1A of the first embodiment.

[0083] According to the structure of the beam-column joint 1E of the fifth embodiment, the same effects as those of the structure of the beam-column joint 1A of the first embodiment can be obtained. (Sixth embodiment) Figures 8(a) and 8(b) show longitudinal cross-sectional views of a beam-column joint 1F according to a sixth embodiment of the present invention. Figure 8(c) shows a perspective view of the beam-column joint 1F according to the sixth embodiment of the present invention. Figure 8(a) also shows the distribution of shear force generated horizontally in a reinforced concrete column 2.

[0084] As shown in FIGS. 8(a) to 8(c), a beam-column joint 1F of the sixth embodiment is a beam-column joint in which five steel beams 3A, 4, 5A, 5C, and 5D made of H-shaped steel are joined to a reinforced concrete column 2 so that they penetrate the column. The five steel beams 3A, 4, 5A, 5C, and 5D are joined to the reinforced concrete column 2 so that they are positioned at different heights. In the main direction, the steel beams 3A and 5A are joined to one side of the reinforced concrete column 2 so that they are lined up above and below, and a steel beam 4 is joined to the other side of the reinforced concrete column 2. In the orthogonal direction, two steel beams 5C and 5D are joined to the reinforced concrete column 2. The beam depths of the steel beams 3A and 4 are equal, and the beam depth of the steel beam 5A is smaller than the beam depth of the steel beams 3A and 4. The beam depth of steel beams 5C and 5D is smaller than the beam depth of steel beams 3A and 4, but larger than the beam depth of steel beam 5A.

[0085] In addition, the height of the upper end of the steel beam 3A is different from the height of the upper ends of the steel beams 4, 5A, 5C, and 5D, and the lower end of the upper steel beam 3A is higher than the upper ends of the lower steel beams 4, 5A, 5C, and 5D. In other words, the beam height of the upper steel beam 3A among the steel beams 3A, 4, and 5A arranged in the main direction is: B D1 (mm), beam depth of lower steel beam 4: B D2 (mm), Center distance between upper steel beam 3A and lower steel beam 4: B If H (mm), the step ratio of steel beams 3A and 4 is 2 BH / ( B D1+ B D2)>1.

[0086] Of the steel beams 3A, 4, and 5A arranged in the main direction, the bottom flange 33 of the upper steel beam 3A and the top flange 42 of the lower steel beam 4 are joined by a tie plate 6. The tie plate 6 is arranged in the same plane as the webs 31 and 41 of the upper steel beam 3A and the lower steel beam 4 joined by this tie plate 6.

[0087] As shown in Figures 8(a) to 8(c), the two steel beams 5C and 5D joined to both sides of the reinforced concrete column 2 in the orthogonal direction are joined to both sides of the portion where the lower steel beam 4 of the steel beams 3A, 4, and 5A arranged in the main direction penetrates the reinforced concrete column 2. Specifically, the two steel beams 5C and 5D arranged in the orthogonal direction are arranged so as to penetrate the steel beam 4 arranged in the main direction, and are welded to both sides of the steel beam 4.

[0088] 8(a) to 8(c), on both sides of the portion where the upper steel beam 3A of the steel beams 3A, 4, and 5A arranged in the main direction penetrates the reinforced concrete column 2, anchoring portions 34 for holding the cover plates 22 are arranged so as to penetrate the steel beam 3A and are welded to both sides of the steel beam 3A. The anchoring portions 34 are made of H-shaped steel having the same beam depth as the steel beam 3A.

[0089] The lower flange of the H-shaped steel that constitutes the anchoring portion 34 and the upper flanges 52 of the steel beams 5C and 5D that are arranged in the perpendicular direction are joined by a connecting plate 6. The connecting plate 6 is arranged in the same plane as the webs of the H-shaped steel that constitute the anchoring portion 34 that are joined by this connecting plate 6 and the webs 51 of the steel beams 5C and 5D.

[0090] Furthermore, as shown in Figure 8(a), on both sides of the portion where the lower steel beam 4 of the steel beams 3A, 4, 5A arranged in the main direction penetrates the reinforced concrete column 2, at a position below the steel beams 5C, 5D in the orthogonal direction, anchoring portions 45 for holding the cover plates 22 are arranged so as to penetrate the steel beam 4, and are welded to both sides of the steel beam 4 and to the bottom flanges 53 of the steel beams 5C, 5D in the orthogonal direction. The anchoring portions 45 are made of steel plates with a height that is the difference between the beam depth of the steel beam 4 in the main direction and the beam depth of the steel beams 5C, 5D in the orthogonal direction.

[0091] In the structure of a beam-column joint 1F of the sixth embodiment, as shown in Fig. 8(a), in the beam-column joint 1F, the webs 31, 41 of the steel beams 3A, 4 in the main direction are reinforced by a doubler plate 7. Specifically, the entire length of the outer periphery of the doubler plate 7 is fixed to the webs 31, 41 of the steel beams 3A, 4 by fillet welding or the like. Similarly, as shown in Fig. 8(b), in the beam-column joint 1F, the webs 51 of the steel beams 5C, 5D in the orthogonal direction are also reinforced by a doubler plate 7.

[0092] In this way, in the structure of the beam-column joint 1F of the sixth embodiment, doubler plates 7 are installed and reinforced on the webs 31, 41, 51 of the steel beams 3A, 4, 5C, 5D within the beam-column joint 1F, so that the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joint 1F.

[0093] In the structure of the beam-column joint 1F of the sixth embodiment, as shown in Fig. 8(a), concrete filling holes 31h, 41h, 7h are provided in the portions of the webs 31, 41 of the steel beams 3A, 4 in the main direction that penetrate into the reinforced concrete column 2 and in the doubler plate 7 fixed to these portions. Similarly, as shown in Fig. 8(b), concrete filling holes 51h, 7h are also provided in the portions of the webs 51 of the steel beams 5C, 5D in the orthogonal direction that penetrate into the reinforced concrete column 2 and in the doubler plate 7 fixed to these portions.

[0094] In the structure of the beam-column joint 1F of the sixth embodiment, the webs 31, 41, 51 of the steel beams 3A, 4, 5C, 5D in the beam-column joint 1F between the reinforced concrete column 2 and the steel beams 3A, 4, 5A, 5C, 5D are reinforced by the doubler plate 7, which makes it possible to open large concrete filling holes 31h, 41h, 51h, 7h in the webs 31, 41, 51 of the steel beams 3A, 4, 5C, 5D in the beam-column joint 1F and in the doubler plate 7. This improves the filling of concrete in the beam-column joint 1F and makes pouring the concrete easier.

[0095] Furthermore, in the structure of the beam-column joint 1F of the sixth embodiment, as shown in FIG. 8(a), the tie plate 6 connecting the upper steel beam 3A and the lower steel beam 4 among the steel beams 3A, 4, and 5A arranged in the main direction also has a concrete filling hole 6h. As shown by the shear force distribution shown on the right side of FIG. 8(a), in the structure of the beam-column joint 1F of the sixth embodiment, the shear force acting on the tie plate 6 is smaller than the shear force acting on the webs 31 and 41 of the steel beams 3A and 4. Therefore, the diameter of the hole 6h formed in the tie plate 6 can be larger than the diameter of the holes 31h and 41h formed in the webs 31 and 41 of the steel beams 3A and 4. This further improves the filling ability of concrete in the beam-column joint 1F, making concrete pouring easier.

[0096] In other respects, the column-beam joint 1F of the sixth embodiment is configured similarly to the column-beam joint 1C of the third embodiment.

[0097] The beam-column joint 1F of the sixth embodiment provides the same effects as the beam-column joint 1C of the third embodiment. (When the end of the brace is connected to the column-beam joint) 9(a) and 9(b) are side views showing a state in which the end of a brace 8 is joined to a beam-column joint 1A' in a structure of a beam-column joint 1A' according to a modification of the first embodiment of the present invention. FIG. 9(a) shows a case in which the brace 8 joined to the beam-column joint 1A' is arranged in the same span as the steel beam 3A on the upper side. FIG. 9(b) shows a case in which the brace 8 joined to the beam-column joint 1A' is arranged in the same span as the steel beam 4 on the lower side.

[0098] 10 shows a side view of a beam-column joint 1B' according to a modified example of the second embodiment of the present invention, in which the end of a brace 8 is joined to the beam-column joint 1B'. Fig. 10 shows a case in which the brace 8 joined to the beam-column joint 1B' is arranged in the same span as the steel beam 3A with the greater beam depth of the steel beams 3A and 5 arranged in the main direction.

[0099] 11(a) and 11(b) show side views of a beam-column joint 1C' according to a modification of the third embodiment of the present invention, with the end of a brace 8 joined to the beam-column joint 1C'. FIG. 11(a) shows a case in which the brace 8 joined to the beam-column joint 1C' is located in the same span as the upper steel beam 3A. FIG. 11(b) shows a case in which the brace 8 joined to the beam-column joint 1C' is located in the same span as the lower steel beam 4. In the beam-column joint 1C' according to the modification of the third embodiment, a doubler plate 7 is provided only in the portion of the web of the steel beam that penetrates the reinforced concrete column 2 in the span where the brace 8 is provided. In other words, a doubler plate 7 is not provided in the portion of the web of the steel beam that penetrates the reinforced concrete column 2 in the span where the brace 8 is not provided. In other respects, the structure of the beam-column joint 1C' of the modified example of the third embodiment is configured in the same manner as the structure of the beam-column joint 1C of the third embodiment shown in Figures 5(a) to 5(c).

[0100] 12(a) and 12(b) are side views showing a state in which the end of a brace 8 is joined to a beam-column joint 1D' according to a modification of the fourth embodiment of the present invention. FIG. 12(a) shows a case in which the brace 8 joined to the beam-column joint 1D' is located in the same span as the upper steel beam 3A. FIG. 12(b) shows a case in which the brace 8 joined to the beam-column joint 1D' is located in the same span as the lower steel beam 4. In the beam-column joint 1D' structure according to the modification of the fourth embodiment, a doubler plate 7 is provided only in the portion of the web of the steel beam placed in the span where the brace 8 is provided that penetrates the reinforced concrete column 2. In other words, a doubler plate 7 is not provided in the portion of the web of the steel beam placed in the span where the brace 8 is not provided that penetrates the reinforced concrete column 2. In other respects, the structure of the beam-column joint 1D' of the modified example of the third embodiment is configured similarly to the structure of the beam-column joint 1D of the third embodiment shown in Figures 6(a) and 6(b).

[0101] 13 shows a side view of a beam-column joint 1E according to a fifth embodiment of the present invention, in which the end of a brace 8 is joined to the beam-column joint 1E. Fig. 13 shows a case in which the brace 8 joined to the beam-column joint 1E is arranged in the same span as one steel beam 3B of two steel beams 3A, 3B arranged in the main direction.

[0102] In each of the examples shown in Figures 9(a), 9(b), 10, 11(a), 11(b), 12(a), 12(b), and 13, brace 8 is joined to beam-column joints 1A' to 1D', 1E so that the central axis of brace 8 is eccentric by a distance e with respect to the intersection of the center of the beam depth of the steel beam located in the same span as brace 8 and the center of the material axis of reinforced concrete column 2. The portion of the web of the steel beam located in the same span as brace 8 that penetrates into reinforced concrete column 2 is reinforced with a doubler plate 7.

[0103] As shown in Figures 9(a), 9(b), 10, 11(a), 11(b), 12(a), 12(b), and 13, when the central axis of the brace 8 is eccentrically connected to the beam-column joints 1A'-1D' and 1E, an additional bending moment acts on the beam-column joints 1A'-1D' and 1E from the brace 8. As a result, the shear force acting on the beam-column joints 1A'-1D' and 1E also increases. Therefore, as shown in Figures 9(a), 9(b), 10, 11(a), 11(b), 12(a), 12(b), and 13, by reinforcing the portion of the web of the steel beam located in the same span as the brace 8 that penetrates the reinforced concrete column 2 with a doubler plate 7, the strength of the beam-column joints 1A'-1D' and 1E can be sufficiently ensured with a relatively simple structure.

[0104] In the above embodiment, an example was described in which the beam-column joint structure of the present invention was applied to a beam-through type column joint with a cover plate, but the beam-through type column joint structure of the present invention can also be applied to a beam-through type column joint with shear reinforcement. In this case, the end of the steel beam does not need to penetrate completely from one side of the reinforced concrete column to the opposite side; it is sufficient that the end of the steel beam 3 penetrates from one side of the reinforced concrete column 2 to the opposite side just long enough to be sufficiently fixed in the beam-column joint.

[0105] In the structures of the beam-column joints 1A-1F, 1A'-1D' according to each of the above embodiments, the reinforced concrete column 2 and the steel beams 3A-3D, 4, 5A, 5C, and 5D preferably have dimensions and material strengths that satisfy the following formula (1). This ensures sufficient shear strength of the beam-column joints 1A-1F, 1A'-1D'.

[0106] J Q dU < w Q+ h Q+ c Q ……(1) However, in the above formula (1), J Q dU: Shear force acting on the column-beam joint at the ultimate state (N) w Q: Shear strength (N) of the web of a steel beam reinforced with a doubler plate in a beam-column joint panel. w Q= w τ U × w A e ……(2) h Q: Shear strength of the cover plate (N), c Q: Shear strength of concrete (N) c Q= cp k· C b· C D ……(3) In the above formula (2), w τ U :Shear strength of the web of a steel beam reinforced with doubler plates in a beam-column joint panel (N / mm 2 ) w A e : Effective cross-sectional area of ​​the web of a steel beam reinforced by a doubler plate in a beam-column joint panel (mm 2 ) and w A e =0.9×( w t+0.8 d t)× C D ……(4) In the above formula (4), w t: thickness of the steel beam web in the beam-column joint (mm), d t: thickness of doubler plate (mm), C D: Depth of reinforced concrete column (mm) In the above formula (3), cp k: Effective section modulus of concrete in the beam-column joint panel, cp k=0.32 C D / BD-0.028 C b / B b+0.204 ……(5) C b: Width of reinforced concrete column (mm) C D: Depth of reinforced concrete column (mm) In the above formula (5), B b: Steel beam width (mm) B D: Depth of steel beam (mm) is.

[0107] In the first embodiment, the beam depths of the four steel beams 3A, 3C, 3D, and 4 are equal to each other, and the height of the upper ends of the steel beams 3A, 3C, and 3D is different from the height of the upper end of the steel beam 4. Therefore, the distance between the upper surface of the upper flange 32 of the upper steel beam 3A, 3C, and 3D among these steel beams 3A, 3C, 3D, and 4 and the lower surface of the lower flange 43 of the lower steel beam 4 is set to B Let's call it D.

[0108] In the second embodiment, among the four steel beams 3B to 3D and 5A arranged so that the heights of the upper ends are equal to each other, the beam depth of the steel beams 3B to 3D having the largest beam depth is B Let's call it D.

[0109] In the third and fourth embodiments, the four steel beams 3A, 3C, 3D, and 4 are arranged so that the height of the top end of the steel beams 3A, 3C, and 3D is different from the height of the top end of the steel beam 4, but the beam depths of these four steel beams 3A, 3C, 3D, and 4 are the same. Therefore, the beam depths of these steel beams 3A, 3C, 3D, and 4 are B Let's call it D.

[0110] In the case of the fifth embodiment, among the four steel beams 3A, 3B, 5C, and 5D arranged so that the heights of the upper ends are equal to each other, the beam depth of the steel beams 3A and 3B in the main direction where the beam depth is the maximum is B Let's call it D.

[0111] In the sixth embodiment, of the five steel beams 3A, 4, 5A, 5C, and 5D, the height of the top end of the steel beam 3A is different from the height of the top ends of the steel beams 4, 5A, 5C, and 5D. In the main direction, the steel beams 3A and 5A are joined to one side of the reinforced concrete column 2 in a vertically aligned manner, and the steel beam 4 is joined to the other side of the reinforced concrete column 2. In the orthogonal direction, two steel beams 5C and 5D are joined to the reinforced concrete column 2. Therefore, of the steel beams 3A, 4, and 5A arranged in the main direction, the beam depth of the steel beams 3A and 4 in the main direction, which have the greatest beam depth, is determined as follows: B Let's call it D.

[0112] Shear force input from 3A-3D, 4, 5A, 5C, and 5D to beam-column joints 1A-1F and 1A'-1D' J Within the beam-column joints 1A-1F and 1A'-1D', Q is shared and borne by the webs 31, 41, 51 of 3A-3D, 4, 5A, 5C, and 5D, the doubler plate 7, the cover plate 22, and the concrete. In other words, the total shear force borne by the webs 31, 41, 51 of 3A-3D, 4, 5A, 5C, and 5D and the doubler plate 7 is w Q, the shear force borne by the cover plate 22 h Q: Shear force borne by concrete cp Let Q be J Q= w Q+ h Q+ cp It becomes Q.

[0113] Similarly, the ultimate shear strength of beam-column joints 1A-1F and 1A'-1D' J Q sU is the total shear strength of webs 31, 41, 51 and doubler plate 7 of 3A to 3D, 4, 5A, 5C, and 5D. w Q sU , the shear strength of the cover plate 22 h Q sU , the shear strength of concrete cp Q sU Then, J Q sU = w Q sU + h QsU + cp Q sU This becomes:

[0114] Shear strength of beam-column joints J Q sU is the shear force acting on beam-column joints 1A-1F and 1A'-1D' at the ultimate state (during an earthquake) of beam-column joints 1A-1F and 1A'-1D'. J Q dU That is, J Q sU > J Q dU The above formula (1) is based on this.

[0115] In this way, in the beam-column joint structure of each of the above embodiments, the webs 31, 41, and 51 of 3A-3D, 4, 5A, 5C, and 5D in beam-column joints 1A-1F and 1A'-1D' are reinforced by doubler plates 7, so the shear strength of the doubler plates 7 can be added to the shear strength of the entire beam-column joints 1A-1F and 1A'-1D'. However, it has not been established until now how the addition of doubler plates 7 affects the load sharing ratio of each resistance element, or what proportion of the total cross-sectional area of ​​the doubler plates 7 effectively contributes to shear strength. In the beam-column joint structure of each of the above embodiments, as described below, the inventors have newly discovered that 80% or more of the total cross-sectional area of ​​the doubler plates 7 effectively contributes to shear strength. Based on this finding, this contribution rate is reflected in the above equation (4). Furthermore, when no bearing plates are provided at beam-column joints 1A-1F, 1A'-1D' and only thinner cover plates 22 are provided, as described below, the inventors have newly discovered that approximately 90% of the cross-sectional area of ​​the webs 31, 41, 51 reinforced by doubler plates effectively contributes to the shear strength, and this contribution rate is also reflected in the above equation (4).

[0116] In the above formula (4), dThe coefficient 0.8 applied to t (the thickness of the doubler plate) may be changed to a smaller value, for example, 0.7, 0.6, etc. Similarly, the coefficient 0.9 applied to the entire right side of the above equation (4) may be changed to a smaller value, for example, 0.8, 0.7, etc. In this way, J Q dU This increases the safety factor of the column-beam joint against the shear force acting on the column-beam joint at its ultimate state.

[0117] Figure 14 shows the effective section modulus of concrete in the beam-column joint structure of the present invention. cp k and the ratio of column depth to beam depth C D / B The relationship between the effective section modulus of the concrete panel and the beam-column joint structure of the present invention is shown in Fig. 15. cp k and the ratio of column width to beam width C b / B Shows the relationship with b.

[0118] As shown in Figures 14 and 15, the ratio of column depth to beam depth is C D / B As D increases, the effective section modulus of concrete cp There is a tendency for k to become larger. C b / B As b increases, the effective section modulus of concrete cp The above equation (5) is the ratio of column depth to beam depth. C D / B D, and the ratio of column width to beam width C b / B b is the effective section modulus of concrete cp The effect on k is evaluated using the proportional relationship shown by the dashed lines in Figures 14 and 15, and the effective section modulus of concrete is calculated using this mechanical model. cp k is defined. [Explanation of symbols]

[0119] 1A~1F, 1A´~1D´ Column beam joint 2. Reinforced concrete columns 21 Main reinforcement 22 Covering board 3A~3D, 4, 5A, 5C, 5D steel beam 31, 41, 51 Web 32, 42, 52 Upper flange 33, 43, 53 Lower flange 34, 44, 45 Fixing section 6 Connecting board 7 Doubler Plate 31h, 41h, 51h, 6h, 7h holes 8 braces

Claims

1. A column-beam joint structure in which multiple steel beams are inserted into a reinforced concrete column, The plurality of steel beams are joined to the reinforced concrete column so that their positions in the height direction are different from each other, A column-beam joint structure in which a doubler plate is installed in the portion of the web of the steel beam that penetrates the reinforced concrete column.

2. At least two of the plurality of steel beams are arranged within the same structural plane, and the lower end of the upper steel beam, which is the steel beam with a higher beam center, is lower than the upper end of the lower steel beam, which is the steel beam with a lower beam center, The beam-column joint structure according to claim 1 , wherein the doubler plate is positioned at a height between the lower end of the upper steel beam and the upper end of the lower steel beam.

3. 2. The column-beam joint structure according to claim 1, wherein an end of a brace is further connected to the column-beam joint between the reinforced concrete column and the steel beam.

4. 3. The column-beam joint structure according to claim 2, wherein an end of a brace is further connected to the column-beam joint between the reinforced concrete column and the steel beam.

5. At least two of the plurality of steel beams are arranged within the same structural plane, and the lower end of the upper steel beam, which is the steel beam with a higher beam center, is higher than the upper end of the lower steel beam, which is the steel beam with a lower beam center; The lower flange of the upper steel beam and the upper flange of the lower steel beam are joined by a connecting plate, The end of the brace is further joined to the column-beam joint between the reinforced concrete column and the two steel beams, 2. The beam-column joint structure according to claim 1, wherein the doubler plate is disposed in a portion of the web of the steel beam of the two steel beams that is arranged in the same span as the brace, the portion penetrating the reinforced concrete column.

6. 6. The beam-column joint structure according to claim 5, wherein the doubler plate is not disposed in a portion of the web of the steel beam that is not disposed in the same span as the brace, the portion penetrating the reinforced concrete column.

7. The column-beam joint structure according to any one of claims 1 to 6, wherein a hole for filling concrete is provided in the portion of the web of the steel beam that penetrates into the reinforced concrete column and in the doubler plate.

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