Structure of column-beam joint portion and design method of column-beam joint portion

Abstract

To provide structure of a column-beam joint portion between reinforced concrete columns and steel beams and a design method for the column-beam joint portion that enhance strength of the column-beam joint portion with a relatively simple configuration, to offer superior economic efficiency, constructability, and structural performance in the column-beam joint portions.SOLUTION: In structure of a column-beam joint portion between a reinforced concrete column and steel beams, an end portion of the steel beam penetrates from one side surface of the reinforced concrete column to the opposite side surface, and a portion of a web of the steel beam that penetrates into the reinforced concrete column is reinforced by a doubler plate.SELECTED DRAWING: Figure 3

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, and a method for designing the column-beam joint. [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] The structure of a beam-through type column-beam joint can be classified into two types: one in which a cover plate is provided to surround the concrete in the column-beam joint 1 as shown in Figure 1 (hereinafter referred to as the cover plate type), and one in which the concrete in the column-beam joint is reinforced with shear reinforcement bars and a support plate is provided at the column face position of the steel beam (hereinafter referred to as the shear reinforcement bar type).

[0005] Non-Patent Document 1 describes design guidelines for the structure of beam-column joints of this type, including those with through-beam cover plates and those with through-beam shear reinforcement. In the design guidelines described in Non-Patent Document 1, for beam-column joints of the shear reinforcement type as well as those with through-beam cover plates, as shown in Figure 2, bearing plates 35 are provided at the column face positions of the steel beams 3, which increases the bearing capacity of the concrete in the beam-column joint 1' through a frame effect, providing advantages in terms of structural performance.

[0006] Furthermore, Non-Patent Document 2, Patent Document 1, and Patent Document 2 disclose specific examples of the structure of a beam-column joint with a beam-penetrating cover plate type.

[0007] Non-Patent Document 2 discloses the results of a performance confirmation experiment conducted in a beam-to-column joint using a beam-penetration type cover plate, in which the thickness of the cover plate was reduced.

[0008] Patent Document 1 discloses a beam-column joint structure in which a gusset plate is integrally attached to the column face of a steel beam and a cover plate is bolted to this gusset plate. This allows the bolt holes to absorb component errors, and eliminates the need for high-precision processing and welding techniques when manufacturing and installing the cover plate.

[0009] Patent Document 2 discloses a beam-column joint structure in which the cover plate surrounding the concrete in the beam-column joint is extended below the bottom flange of the steel beam. This reduces the amount of shear reinforcement in the beam-column joint and improves concrete filling. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2018-119316 [Patent Document 2] Japanese Patent Publication No. 2022-076025 [Non-patent literature]

[0011] [Non-Patent Document 1] Architectural Institute of Japan, "Design Guidelines for Mixed Structures with Reinforced Concrete Columns and Steel Beams, 1st Edition," Architectural Institute of Japan, February 2021 [Non-patent document 2] Takahisa Mori et al., "Experiment on Shear Strength of Beam-Column Joints with Cover Plates in RCS Structures," Proceedings of the Annual Meeting of the Architectural Institute of Japan (Kanto), Architectural Institute of Japan, July 2006, pp. 1099-1100 Summary of the Invention [Problem to be solved by the invention]

[0012] In the structure of the beam-through type column-beam joint as described above, the following problems arise when trying to increase the strength.

[0013] 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.

[0014] Furthermore, if an attempt is made to increase the frame effect of restraining the concrete in the column-beam joint by increasing the thickness of the cover plate, 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.

[0015] 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.

[0016] The present invention has been made to solve the above-mentioned problems, and aims to provide a column-beam joint structure and a design method for a column-beam joint between a reinforced concrete column and a steel beam, 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]

[0017] The means for solving the above problems are as follows. [1] A column-beam joint structure between a reinforced concrete column and a steel beam, in which the end of the steel beam penetrates from one side of the reinforced concrete column to the opposite side, and the portion of the web of the steel beam that penetrates the reinforced concrete column is reinforced with a doubler plate. [2] A structure of a beam-column joint described in [1], in which a cover plate is provided that surrounds the side of the reinforced concrete column up to the surface position of the web of the steel beam within the height range between the upper flange and the lower flange of the steel beam. [3] The structure of a beam-column joint described in claim 2, wherein the reinforced concrete column and the steel beam in the height range between the upper flange and the lower flange of the steel beam have dimensions and material strength that satisfy the following formula (1).

[0018] 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), 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 ……(3) In the above formula (3), 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) is. [4] A column-beam joint structure described in [1], in which a support plate that supports the concrete in the column-beam joint is provided in the area surrounded by the web, upper flange, and lower flange of the steel beam, and a cover plate that surrounds the part of the side of the reinforced concrete column that is not covered by the support plate is provided so as to be continuous with the support plate within the height range between the upper flange and lower flange of the steel beam.

[0019] The bearing plate shall be made of a steel plate having a thickness equal to or greater than the thickness of the web of the steel beam. [5] A column-beam joint structure described in [4], in which the reinforced concrete column and the steel beam in the height range between the upper flange and the lower flange of the steel beam have dimensions and material strength that satisfy the following formula (1).

[0020] 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 cover plate and bearing plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced with a doubler plate 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 =( 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) is. [6] Width of the cover plate h b (mm) and thickness ht (mm) is h b / h t ≤ 217 and h A column-beam joint structure according to any one of [2] to [5], which satisfies the relationship t≧6. [7] A structure of a beam-column joint described in any one of [1] to [5], in which 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. [8] A structure of a beam-column joint described in [6], in which the portion of the web of the steel beam that penetrates the reinforced concrete column and the doubler plate have holes for filling concrete. [9] A column-beam joint structure described in any of [1] to [5], in which the end of the brace is attached eccentrically with respect to the intersection between the core of the steel beam and the core of the reinforced concrete column.

[10] A method for designing a column-beam joint, in which the end of a steel beam to be joined to a reinforced concrete column is inserted from one side of the reinforced concrete column to the opposite side, the portion of the web of the steel beam that penetrates the reinforced concrete column is reinforced with a doubler plate, and a cover plate is provided to surround the side of the reinforced concrete column up to the surface position of the web of the steel beam within the height range between the upper flange and the lower flange of the steel beam, and the dimensions and material strength of the reinforced concrete column and the steel beam within the height range between the upper flange and the lower flange of the steel beam are set so as to satisfy the following formula (1):

[0021] 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), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced with a doubler plate 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 ……(3) In the above formula (3), 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) is.

[11] A method for designing a column-beam joint, in which the end of a steel beam to be joined to a reinforced concrete column is inserted from one side of the reinforced concrete column to the opposite side, the portion of the web of the steel beam that penetrates the reinforced concrete column is reinforced with a doubler plate, a support plate that supports the concrete in the column-beam joint is provided in the area surrounded by the web, upper flange, and lower flange of the steel beam, and a cover plate that surrounds the portion of the side of the reinforced concrete column that is not covered by the support plate is provided so as to be continuous with the support plate within the height range between the upper flange and lower flange of the steel beam, and the dimensions and material strength of the reinforced concrete column and the steel beam within the height range between the upper flange and lower flange of the steel beam are set so as to satisfy the following formula (1).

[0022] 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 cover plate and bearing plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced with a doubler plate 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 =( 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) is.

[0023] The bearing plate shall be made of a steel plate having a thickness equal to or greater than the thickness of the web of the steel beam. [Effects of the Invention]

[0024] According to the beam-column joint structure and beam-column joint design method of the present invention, the web of the steel beam in the beam-column joint between a reinforced concrete column and a steel beam is reinforced with a doubler plate, which increases the strength of the beam-column joint with a relatively simple structure. This makes it possible 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 a reinforced concrete column and a steel beam.

[0025] Furthermore, because the portion of the steel beam web that penetrates the reinforced concrete column is reinforced with a doubler plate, it is possible to drill large holes for concrete filling in the steel beam web and doubler plate, which improves the filling of concrete into the beam-column joint and makes pouring the concrete easier. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a perspective view showing an example of the structure of a beam-to-column joint of the beam-penetration type with a cover plate. [Figure 2] FIG. 2 is a perspective view showing another example of the structure of a beam-to-column joint of the beam-penetrating type covering plate type. [Figure 3] 3(a) and 3(b) are a perspective view and a side view, respectively, showing the main part of an example of the structure of a beam-column joint according to the present invention. [Figure 4] FIG. 4 is a schematic diagram illustrating the flow of shear force in the column-beam joint structure of the present invention. [Figure 5] FIG. 5 is a side view that schematically shows a situation in which a brace is attached eccentrically to a beam-column joint. [Figure 6] 6(a) and 6(b) are a perspective view and a side view, respectively, showing the main part of another example of the column-to-beam joint structure of the present invention. [Figure 7] Figure 7(a) is a side view showing a test specimen for a loading test conducted to verify the effectiveness of the structure of the beam-column joint and the design method for the beam-column joint of the present invention, and Figures 7(b) and 7(c) are cross-sectional views along the lines BB and CC in Figure 7(a), respectively. [Figure 8] FIG. 8 is a graph showing the relationship between the shear strength Q of a column and the story drift angle R in a loading test conducted to verify the effectiveness of the beam-column joint structure and the beam-column joint design method of the present invention. [Figure 9] Figure 9(a) is a perspective view showing an analytical model used in a numerical analysis conducted to verify the structure of a beam-column joint and the effects of the design method for a beam-column joint of the present invention, and Figure 9(b) is a side view. [Figure 10] Figure 10 is a graph showing the distribution of shear stress occurring in the web of a steel beam within a beam-column joint panel at the end of the beam-column joint, as determined by a numerical analysis conducted to confirm the effectiveness of the beam-column joint structure and design method of the present invention. [Figure 11] Figure 11 is a graph showing the distribution of shear stress generated in the doubler plate in the beam-column joint panel at the end of the beam-column joint in a numerical analysis conducted to confirm the effectiveness of the beam-column joint structure and the beam-column joint design method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, with reference to the drawings, embodiments of the column-beam joint structure and the column-beam joint design method of the present invention will be specifically described.

[0028] The column-beam joint structure and column-beam joint design method of this embodiment are applied to a column-beam joint between a reinforced concrete column and a steel beam made of H-shaped steel, specifically, a column-beam joint 1 of the beam-penetrating type with a cover plate shown in Figure 1, or a column-beam joint 1' of the beam-penetrating type with a cover plate shown in Figure 2.

[0029] 3(a) and 3(b) are a perspective view and a side view, respectively, of the main parts of the structure of the beam-column joints 1, 1' of this embodiment.

[0030] As shown in Figures 1, 3(a) and 3(b), in the structure of the beam-column joints 1, 1' of this embodiment, the end of the steel beam 3 penetrates from one side of the reinforced concrete column 2 to the opposite side.

[0031] In the structure of the beam-column joint 1 shown in Figure 1, a cover plate 24 made of a steel plate is provided to surround the concrete (not shown) poured continuously within the beam-column joint 1 from the reinforced concrete columns 2 above and below the beam-column joint 1. The cover plate 24 is provided so as to completely cover the concrete within the beam-column joint 1 up to the surface of the web 31 of the steel beam 3, within the height range between the upper flange 32 and the lower flange 33 of the steel beam 3. The side edges of the cover plate 24 are fixed to the web 31, upper flange 32, and lower flange 33 of the steel beam 3 by welding.

[0032] In the structure of the beam-column joint 1′ shown in FIG. 2 , a bearing plate 35 that supports the concrete in the beam-column joint 1′ is provided in the area surrounded by the web 31, upper flange 32, and lower flange 33 of the steel beam 3. The bearing plate 35 is made of a steel plate that is thicker than the web 31 of the steel beam 3 and is fixed to the web 31, upper flange 32, and lower flange 33 of the steel beam 3 by welding. A cover plate 24 is provided to surround the portion of the concrete (not shown) that is poured continuously from the reinforced concrete columns 2 above and below the beam-column joint 1 into the beam-column joint 1′ but remains uncovered by the bearing plate 35. The bearing plate 35 and the cover plate 24 are provided so as to completely cover the concrete in the beam-column joint 1 up to the surface of the web 31 of the steel beam 3, within the height range between the upper flange 32 and lower flange 33 of the steel beam 3. The cover plate 24 is provided so as to be continuous with the support plate 35 and is fixed to the support plate 35 by welding or bolting.

[0033] 1 and 2 show a case where steel beams 3 are attached in a cross shape to the four sides of a reinforced concrete column 2. In this case, both of the cross-shaped steel beams 3 are installed so as to completely penetrate the reinforced concrete column 2 from one side to the opposite side.

[0034] In addition, when the steel beams 3 are attached to three sides of the reinforced concrete column 2 in a T-shape, or when the steel beams 3 are attached to two sides of the reinforced concrete column 2 in an L-shape, both of the steel beams 3 that intersect in a T-shape or L-shape are arranged so that they completely penetrate from one side of the reinforced concrete column 2 to the opposite side.

[0035] Furthermore, at the portion where the steel beam 3 that penetrates the reinforced concrete column 2 protrudes onto the opposite side of the reinforced concrete column 2, the side edge of the cover plate 24 or the support plate 35 is fixed by welding to the web 31, upper flange 32, and lower flange 33 of the steel beam 3.

[0036] In the structure of the beam-column joints 1, 1' of this embodiment, as shown in Figures 3(a) and 3(b), the web 31 of the steel beam 3 in the beam-column joints 1, 1' is reinforced by a doubler plate 34. Specifically, the entire length of the outer periphery of the doubler plate 34 is fixed to the web 31 of the steel beam 3 by fillet welding or the like.

[0037] It is preferable that the reinforced concrete column 2 and the steel beam 3 in the beam-column joint 1 shown in Figure 1 have dimensions and material strength that satisfy the following formula (1). This ensures sufficient shear strength of the beam-column joint 1.

[0038] 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), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced with a doubler plate 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 Ae =0.9×( w t+0.8 d t)× c D ……(3) In the above formula (3), 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) is.

[0039] 4 is a schematic diagram showing the flow of shear force in the beam-column joint structure of this embodiment. As shown in FIG. 4, the shear force input from the steel beam 3 to the beam-column joint 1 is J Within the beam-column joint 1, Q is shared and borne by the web 31 of the steel beam 3, the doubler plate 34, the cover plate 24, and the concrete 23. In other words, the total shear force borne by the web 31 of the steel beam 3 and the doubler plate 34 is w Q, the shear force borne by the cover plate 24 h Q: The shear force borne by concrete 23 cp Let Q be J Q= w Q+ h Q+ cp It becomes Q.

[0040] Similarly, the ultimate shear strength of beam-column joint 1 J Q sU is the total shear strength of the web 31 and doubler plate 34 of the steel beam 3. w Q sU , the shear strength of the cover plate 24 h Q sU , the shear strength of concrete 23 cp Q sU Then, J Q sU = w Q sU + h Q sU + cp Q sU This becomes:

[0041] Shear strength of beam-column joints J Q sU is the shear force acting on column-beam joint 1 at its ultimate state (during an earthquake) J Q dU That is, J Q sU > J Q dU The above formula (1) is based on this.

[0042] In this way, in the beam-column joint structure of this embodiment, the web 31 of the steel beam 3 in the beam-column joint 1 is reinforced by the doubler plate 34, so the shear strength of the doubler plate 34 can be added to the shear strength of the entire beam-column joint 1. However, it has not been established until now how the provision of the doubler plate 34 changes the burden ratio of each resistance element, or what proportion of the total cross-sectional area of the doubler plate 34 effectively contributes to shear strength. In the beam-column joint structure of this embodiment, as described below, based on new findings by the inventors that 80% or more of the total cross-sectional area of the doubler plate 34 effectively contributes to shear strength, this contribution rate is reflected in the above formula (3). Furthermore, when no bearing plate 35 is provided at the beam-column joint 1 and only a thinner cover plate 24 is provided, as will be described later, the inventors have newly discovered that approximately 90% of the cross-sectional area of the web 31 reinforced by the doubler plate effectively contributes to the shear strength, and this contribution rate is also reflected in the above equation (3).

[0043] In the above formula (3), d The 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-hand side of the above equation (3) 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 1 against the shear force (the shear force acting on the column-beam joint 1 at the end of the column-beam joint).

[0044] Furthermore, it is preferable that the reinforced concrete column 2 and the steel beam 3 in the beam-column joint 1' shown in Figure 2 have dimensions and material strength that satisfy the following formula (1). This ensures sufficient shear strength of the beam-column joint 1'.

[0045] 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 cover plate and bearing plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced with a doubler plate 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 =( 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) is.

[0046] In this way, in the structure of the beam-column joint 1' shown in Figure 2, the shear strength of the concrete is effectively enhanced by the bearing plate 35, so it is sufficient to satisfy the above equation (4) instead of the above equation (3).

[0047] Also, the width of the cover plate 24 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 prevents buckling of the cover plate 24 and provides a sufficient frame effect that restrains the concrete with the cover plate 24, further increasing the bearing capacity of the beam-column joint 1.

[0048] Here, the width of the blocking plate 24 h b (mm) refers to the overall width of each of the cover plates 24 provided between horizontally adjacent steel beams 3 among the multiple steel beams 3 attached to the reinforced concrete column 2. For example, in the structure of the beam-column joint 1, 1' shown in Figures 1 and 2, four cover plates 24 bent into an L-shape are provided to cover the concrete (not shown) between the adjacent steel beams 3. h b (mm) refers to the overall width of each of these closing plates 24 before bending.

[0049] Furthermore, it is preferable that the thickness of the bearing plate 35 is equal to or greater than the thickness of the web 31 of the steel beam 3 so as to satisfy the design guidelines described in Non-Patent Document 1. In this way, the bearing effect of the bearing plate 35 on the concrete is enhanced, and the shear strength borne by the concrete in the beam-column joints 1, 1' can be fully exerted. Furthermore, the frame effect of the bearing plate 35 can increase the shear strength borne by the web 31 and doubler plate 34 of the steel beam 3 in the beam-column joints 1, 1'. According to the above formula (4), w A e (effective cross-sectional area of the web 31 of the steel beam 3 reinforced by the doubler plate 34) is calculated by the above formula (3) when the bearing plate 35 is not provided. w A e The fact that it is larger than

[0050] The design method for a column-beam joint of this embodiment is a method for designing the above-mentioned column-beam joints 1, 1'. That is, as shown in FIG. 1, when the column-beam joint 1 does not include a bearing plate 35 and only includes a thinner cover plate 24, the design method for a column-beam joint of this embodiment is realized by setting the dimensions and material strength of the reinforced concrete column and steel beam within the height range between the upper flange and the lower flange of the steel beam so as to satisfy the above-mentioned formulas (1) to (3) when designing the column-beam joint 1. As shown in FIG. 2, when the column-beam joint 1' includes a bearing plate 35, the design method for a column-beam joint of this embodiment is realized by setting the dimensions and material strength of the reinforced concrete column and steel beam within the height range between the upper flange and the lower flange of the steel beam so as to satisfy the above-mentioned formulas (1), (2), and (4) when designing the column-beam joint 1.

[0051] According to the structure of the beam-column joint 1, 1' and the design method of the beam-column joint of this embodiment, the web 31 of the steel beam 3 in the beam-column joint 1, 1' between the reinforced concrete column 2 and the steel beam 3 is reinforced with the doubler plate 34, thereby increasing the strength of the beam-column joint 1, 1' with a relatively simple structure. The structure of the beam-column joint 1, 1' of this embodiment allows the shear strength of the doubler plate 34 to be added to the shear strength of the entire beam-column joint 1, 1', making the design of the beam-column joint 1, 1' easier. Thus, the structure of the beam-column joint 1, 1' of this embodiment simplifies the design of the beam-column joint 1, 1' between the reinforced concrete column 2 and the steel beam 3, while realizing a beam-column joint 1, 1' that is economical, easy to construct, and has excellent structural performance.

[0052] Figure 5 shows a schematic diagram of a situation in which the brace 4 is attached eccentrically to the beam-column joints 1, 1'. As shown in Figure 5, when the brace 4 is attached eccentrically to the beam-column joints 1, 1', or in buildings with large spans and heavy live loads to which an RCS structure is applied, large shear forces are likely to act on the beam-column joints 1, 1'. The structure of the beam-column joints 1, 1' of this embodiment can easily take advantage of its features when applied to beam-column joints where such large shear forces act.

[0053] Furthermore, in the structure of the column-beam joints 1, 1' of this embodiment, the web 31 of the steel beam 3 in the column-beam joints 1, 1' between the reinforced concrete column 2 and the steel beam 3 is reinforced by the doubler plate 34, making it possible to drill large holes for filling concrete in the web 31 and doubler plate 34 of the steel beam 3 in the column-beam joints 1, 1'.

[0054] 6(a) and 6(b) are a perspective view and a side view, respectively, of the beam-column joints 1, 1' of this embodiment, in which holes 31h, 34h for filling concrete are provided in the web 31 and the doubler plate 34 of the steel beam 3 in the beam-column joints 1, 1'. This improves the filling of concrete in the beam-column joints 1, 1', making it easier to pour the concrete.

[0055] 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 the column-beam joints 1, 1' of this embodiment allows concrete of the same strength to be poured integrally within the column-beam joints 1, 1' and the rest of the reinforced concrete column 2. For this reason, the structure of the column-beam joints 1, 1' of this embodiment is excellent in terms of workability and structural performance.

[0056] Furthermore, by reinforcing the webs 31 of the steel beams 3 in the beam-column joints 1, 1' with doubler plates 34, the bearing capacity of the beam-column joints 1, 1' can be increased without increasing the thickness of the cover plate 24. This eliminates the need to increase the bending radius 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.

[0057] Furthermore, in the structure of the beam-to-column joints 1, 1' of this embodiment, instead of increasing the thickness of the web 31 of the entire steel beam 3, the web 31 of the steel beam 3 is reinforced by the doubler plate 34 only within the beam-to-column joints 1, 1'. Therefore, the cost required for the steel beam 3 does not increase.

[0058] In the above embodiment, an example was described in which the beam-column joint structure and beam-column joint design method of the present invention were applied to a beam-through type column joint with a cover plate, but the beam-column joint structure and beam-column joint design method 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. [Example]

[0059] A half-scale cross-shaped specimen was prepared for the beam-column joint structure of the present invention, and a loading test was conducted on this specimen. Numerical analysis was also conducted using the finite element method under conditions simulating the loading test. Based on the results of these loading tests and numerical analysis, the performance of the beam-column joint structure and the beam-column joint design method of the present invention was verified. The results are described below.

[0060] First, the test conditions for the loading test will be explained. Figure 7(a) shows a side view of the specimen used in this loading test. Figures 7(b) and 7(c) show the BB and CC cross sections of Figure 7(a), respectively.

[0061] As shown in Figure 7(a), five types of cross-shaped specimens No. 1 to No. 5 were prepared for this loading test, each consisting of a reinforced concrete column 2 with a steel beam 3 joined to both sides.

[0062] In this loading test, the size and type of the main reinforcement 21 of the reinforced concrete column 2, the width of the upper flange 32 and the lower flange 33 of the steel beam 3 B b (mm) and the thickness of the web 31 w t (mm), thickness of cover plate 24 h t (mm), strength of concrete in beam-column joint 1 F c (N / mm 2 ) and the presence or absence of the doubler plate 34. As shown in Tables 1 and 2, these parameters were varied for five types of test specimens Nos. 1 to 5.

[0063] Specifically, the cross-sectional size of the reinforced concrete column 2 of the test specimen was 500 x 500 mm, and as shown in Figure 7(b), 12 main reinforcements 21 were arranged, and 50 mm tie bars were arranged with 50 mm pitches. The designations and types of the main reinforcements 21 for test specimens No. 1, 2, 4, and 5 were D22 and SD490 as specified in the Japanese Industrial Standard JIS G3112:2020 "Steel Bars for Concrete Reinforcement," and for test specimen No. 3, they were D19 and SD345. The designations and types of the tie bars 22 for all test specimens No. 1 to 5 were MD13 and MD785 as specified in the Ministry of Land, Infrastructure, Transport and Tourism's Kokusyu-shi-shi No. 4958-1 (Certification No. MSRB-0067) "Deformed Steel Bars for High-Strength Shear Reinforcement MK785." The strength F of the concrete poured in the reinforced concrete column 2 of the test specimen was 1000 MPa. c is 39N / mm for all test specimens No. 1 to 5. 2 It was decided.

[0064] Additionally, built-in H-beams were used for the steel beams 3 of the test specimens. The steel beams 3 of test specimens No. 1, 2, 4, and 5 were built-in H-beams with a depth of 450 mm and a width of 160 mm, consisting of 28 mm thick steel plates for the top flange 32 and bottom flange 33 and a 9.0 mm thick steel plate for the web 31. The steel beams 3 of test specimen No. 3 were built-in H-beams with a depth of 450 mm and a width of 200 mm, consisting of 28 mm thick steel plates for the top flange 32 and bottom flange 33 and a 12.0 mm thick steel plate for the web 31. The steel type of the steel beams 3 for all test specimens No. 1 to 5 was SM490, as specified in the Japanese Industrial Standard JIS G3106:2020 "Rolled Steel Plates for Welded Structures."

[0065] The strength of the concrete placed in the beam-column joint 1 of the test specimen is F c For specimens No. 1 to 3 and 5, the stress was 39 N / mm 2 For specimen No. 4, 60N / mm 2The thickness of the cover plate 24 surrounding the concrete poured in the beam-column joint 1 was 2.3 mm for specimens 1 and 3-5, and 6.0 mm for specimen 2. The steel type of the cover plate 24 for all specimens 1-5 was SS400, as specified in the Japanese Industrial Standard JIS G3101:2020 "General structural rolled steel plate." The side edges of the cover plate 24 were fixed to the web 31, top flange 32, and bottom flange 33 of the steel beam 3 by fillet welding.

[0066] Furthermore, among specimens No. 1 to 5, only specimen No. 5 had two doubler plates 34 installed side by side on one side of the web 31 of the steel beam 3 in the beam-to-column joint 1, so as to cover almost the entire surface of the web 31 of the steel beam 3 in the beam-to-column joint 1, as shown in FIG. 7(a). Each of the two doubler plates 34 had dimensions of 3.2 mm thick, 203 mm wide, and 354 mm high, and was made of SS400 steel. The entire length of the outer periphery of the doubler plate 34 was fixed to the surface of the web 31 of the steel beam 3 by fillet welding.

[0067] Then, as shown in Figure 7(a), a cross-shaped specimen was placed on the test frame. Specifically, the upper and lower ends of the reinforced concrete column 2 were supported by pin bearings and roller bearings, respectively. The distance between the pin bearings and the roller bearings was set to 3100 mm.

[0068] Then, to simulate the behavior of a beam-column joint in a building subjected to horizontal load, alternating positive and negative loads were applied in an anti-symmetrical manner to the tips of the two steel beams 3 on both sides of the reinforced concrete column 2. The distance between the two load application points on the steel beams 3 was set to 4,400 mm.

[0069] [Table 1]

[0070] [Table 2]

[0071] In this loading test, the inter-story drift angle R (rad) of the rigid frame frame including the beam-to-column joint 1 was calculated from the displacement of the tip of the steel beam 3, and this inter-story drift angle R was controlled. Specifically, first, one cycle of load was applied in each of the positive and negative directions at inter-story drift angles R of ±0.1% and ±0.25% within the elastic range, then two cycles of load was applied in each of the positive and negative directions at inter-story drift angles R of ±0.5%, ±1.0%, ±1.5%, and ±2.0%, and finally one cycle of load was applied in each of the positive and negative directions at inter-story drift angles R of ±3.0% and ±4.0%.

[0072] This loading test was carried out under the condition that an axial force of axial force ratio N = 0.16 was applied to the reinforced concrete column 2.

[0073] Figure 8 shows the relationship between the column shear strength Q and the story drift angle R in the above-mentioned loading test for specimen No. 1 (without doubler plates) and specimen No. 5 (with doubler plates). As shown in Figure 8, both specimens No. 1 and No. 5 showed stable hysteresis even after reaching the maximum strength (story drift angle R = 2.0%) without buckling of the cover plate 24. Furthermore, specimen No. 5, which was reinforced with doubler plates, had a higher maximum value of the column shear force Q at each cycle than specimen No. 1, which did not have doubler plates 5, confirming that the doubler plates effectively contribute to the performance of the beam-column joint.

[0074] Next, we will explain the calculation conditions for the numerical analysis using the finite element method, which was performed under conditions simulating the above-mentioned loading test. Figure 9(a) shows a perspective view of the finite element model of the test specimen that was the subject of this numerical analysis. Figure 9(b) shows a side view of the main parts of the finite element model shown in Figure 9(a).

[0075] In this numerical analysis, numerical analysis was performed on five types of finite element models corresponding to specimens No. 1 to 5 that were the test subjects in the above-mentioned loading test. That is, in this numerical analysis, the shape and mechanical properties of each element of the finite element model were set so as to reflect the shape and material strength of each member of specimens No. 1 to 5 in the loading test.

[0076] For the finite element model simulating specimen No. 5 of the load test, the two doubler plates 34 were each fixed to the surface of the web 31 over the entire length of their periphery.

[0077] Then, just as in the above-mentioned loading test, the upper and lower ends of the reinforced concrete column 2 were supported by pin bearings and roller bearings, respectively, and a numerical analysis was carried out under the condition that an axial force with an axial force ratio N = 0.16 was applied to the reinforced concrete column 2. As in the above-mentioned loading test, the external force input to the finite element model was an alternating positive and negative gradually increasing repeated load applied anti-symmetrically to the tips of the two steel beams 3 on both sides of the reinforced concrete column 2.

[0078] In these loading tests and numerical analyses, the point at which the story drift angle R reached 0.2 was defined as the ultimate state, and the shear strength of the beam-column joint 1 at this point was confirmed.

[0079] Figure 10 shows the distribution of shear stress occurring in the web 31 of the steel beam 3 in the beam-column joint panel at the ultimate state of the beam-column joint 1 in the above-mentioned numerical analysis performed on each of the finite element models simulating test specimens No. 1 to 5. Also, Figure 11 shows the distribution of shear stress occurring in the doubler plate 34 in the beam-column joint panel at the ultimate state of the beam-column joint 1 in the above-mentioned numerical analysis performed on each of the finite element models simulating test specimen No. 5.

[0080] Table 3 also shows the ultimate shear strength of the web 31 of the steel beam 3 in the beam-column joint 1, the doubler plate 34, the cover plate 24, and the concrete, calculated by the above-mentioned numerical analysis. w Q ana , d Q ana , Σ h Q ana , cp Q ana Table 3 also shows the effective section modulus of the web 31 of the steel beam 3 in the beam-to-column joint 1, the doubler plate 34, the cover plate 24, and the concrete, calculated by the above-mentioned numerical analysis. w kana , d k ana , h k ana , cp k ana , and the ultimate shear strength of the entire beam-column joint 1 J Q ana Shows.

[0081] Furthermore, Table 3 shows the ultimate shear strength of the web 31, doubler plate 34, cover plate 24, and concrete of the steel beam 3 in the column-beam joint 1, calculated using the proposed formula described in the Building Technology Performance Certificate (Performance Certificate No. 23-05) of the General Building Research Corporation of Japan. w Q org ', d Q org ', Σ h Q org ', cp Q org ' is shown. Table 3 also shows the effective section modulus of the web 31 of the steel beam 3 in the column-beam joint 1, the doubler plate 34, the cover plate 24, and the concrete, calculated using the proposed formula. w k org ', d k org ', h k org ', cp k org ', and the ultimate shear strength of the entire beam-column joint 1 J Q org ' indicates.

[0082] Furthermore, Table 3 shows the ultimate shear strength of the entire beam-column joint 1 obtained from the above-mentioned loading test. J Q exp , and the ultimate shear strength of the entire beam-column joint 1 calculated using the proposed formula described in the above-mentioned Building Technology Performance Certificate (Performance Certificate No. 23-05) J Q org Ratio to ' J Q exp / J Q org ' indicates.

[0083] [Table 3]

[0084] As shown in the bold frame in Table 3, the results of the numerical analysis conducted on a finite element model simulating test specimen No. 5 confirmed that more than 80% of the total cross-sectional area of the doubler plate 34 effectively contributed to shear strength.

[0085] In addition, the effective section modulus of the web 31 of the steel beam 3 in the column-beam joint 1 is w k ana was approximately 0.9. In other words, it was confirmed that when the bearing plate 35 is not provided at the beam-column joint 1 and only the thinner cover plate 24 is provided, about 90% of the cross-sectional area of the web 31 effectively contributes to the shear strength. From this, in the above formula (3) when the bearing plate 35 is not provided, w A e (effective cross-sectional area of the web 31 of the steel beam 3 reinforced by the doubler plate 34) is calculated by the above formula (4) when the bearing plate 35 is provided. w A e We were able to confirm the validity of setting the value at 0.9 times the original value. [Explanation of symbols]

[0086] 1, 1´ Column beam joint 2. Reinforced concrete columns 21 Main reinforcement 22 Stirrup 23 Concrete 24 Covering board 3 Steel beams 31 Web 32 Upper flange 33 Lower flange 34 Doubler Plate 35 Bearing plate 31h, 34h hole 4 braces

Claims

1. A structure of a column-beam joint between a reinforced concrete column and a steel beam, The end of the steel beam penetrates from one side of the reinforced concrete column to the opposite side, A beam-column joint structure in which the portion of the web of the steel beam that penetrates the reinforced concrete column is reinforced with a doubler plate.

2. 2. The beam-column joint structure according to claim 1, wherein a cover plate is provided to surround the side of the reinforced concrete column up to the surface of the web of the steel beam in the height range between the upper flange and the lower flange of the steel beam.

3. 3. The column-beam joint structure according to claim 2, wherein the reinforced concrete column and the steel beam in the height range between the upper flange and the lower flange of the steel beam have dimensions and material strengths that satisfy the following formula (1): 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 of the column-beam joint (N) w Q: Shear strength (N) of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel; w Q= w t U × w A e ……(2) h Q: Shear strength of the cover plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel (N / mm 2 ) w A e : Effective cross-sectional area of the web of the steel beam reinforced by the doubler plate in the column-beam joint panel (mm 2 ) and w A e =0.9×( w t+0.8 d t)× c D ……(3) In the above formula (3), w t: thickness of the steel beam web in the column-beam joint (mm), d t: thickness of doubler plate (mm), c D: Depth of reinforced concrete column (mm) is.

4. a bearing plate that supports the concrete in the column-beam joint is provided in a region surrounded by the web, upper flange, and lower flange of the steel beam; The structure of a column-beam joint as described in claim 1, wherein a cover plate is provided to surround the portion of the side of the reinforced concrete column that is not covered by the support plate within the height range between the upper flange and the lower flange of the steel beam, and is continuous with the support plate.

5. 5. The column-beam joint structure according to claim 4, wherein the reinforced concrete column and the steel beam in the height range between the upper flange and the lower flange of the steel beam have dimensions and material strength that satisfy the following formula (1): 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 of the column-beam joint (N) w Q: Shear strength (N) of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel; w Q= w t U × w A e ……(2) h Q: Shear strength of the cover plate and bearing plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel (N / mm 2 ) w A e : Effective cross-sectional area of the web of the steel beam reinforced by the doubler plate in the column-beam joint panel (mm 2 ) and w A e =( w t+0.8 d t)× c D ……(4) In the above formula (4), w t: thickness of the steel beam web in the column-beam joint (mm), d t: thickness of doubler plate (mm), c D: Depth of reinforced concrete column (mm) is.

6. Width of the blocking plate h b (mm) and thickness h t (mm) is h b / h t≦217 and h The structure of a beam-column joint according to any one of claims 2 to 5, satisfying the relationship t≧6.

7. The column-beam joint structure according to any one of claims 1 to 5, 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.

8. 7. The beam-column joint structure according to claim 6, wherein holes for filling concrete are provided in the portion of the web of the steel beam that penetrates into the reinforced concrete column and in the doubler plate.

9. The structure of a beam-column joint according to any one of claims 1 to 5, wherein the end of the brace is attached eccentrically with respect to the intersection between the core of the steel beam and the core of the reinforced concrete column.

10. The end of the steel beam to be joined to the reinforced concrete column is inserted from one side of the reinforced concrete column to the opposite side, The portion of the web of the steel beam that penetrates into the reinforced concrete column is reinforced with a doubler plate; a cover plate is provided to surround the side of the reinforced concrete column up to the surface of the web of the steel beam within the height range between the upper flange and the lower flange of the steel beam; A method for designing a beam-column joint, which sets the dimensions and material strength of the reinforced concrete column and the steel beam within the height range between the upper flange and the lower flange of the steel beam so as to satisfy the following formula (1): 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 of the column-beam joint (N) w Q: Shear strength (N) of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel; w Q= w t U × w A e ……(2) h Q: Shear strength of the cover plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel (N / mm 2 ) w A e : Effective cross-sectional area of the web of the steel beam reinforced by the doubler plate in the column-beam joint panel (mm 2 ) and w A e =0.9×( w t+0.8 d t)× c D ……(3) In the above formula (3), w t: thickness of the steel beam web in the column-beam joint (mm), d t: thickness of doubler plate (mm), c D: Depth of reinforced concrete column (mm) is.

11. The end of the steel beam to be joined to the reinforced concrete column is inserted from one side of the reinforced concrete column to the opposite side, The portion of the web of the steel beam that penetrates into the reinforced concrete column is reinforced with a doubler plate; a bearing plate for bearing pressure on the concrete in the column-beam joint is provided in a portion surrounded by the web, upper flange, and lower flange of the steel beam; A cover plate is provided to surround the portion of the side of the reinforced concrete column that is not covered by the bearing plate within the height range between the upper flange and the lower flange of the steel beam, so as to be continuous with the bearing plate; A method for designing a beam-column joint, which sets the dimensions and material strength of the reinforced concrete column and the steel beam within the height range between the upper flange and the lower flange of the steel beam so as to satisfy the following formula (1): 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 of the column-beam joint (N) w Q: Shear strength (N) of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel; w Q= w t U × w A e ……(2) h Q: Shear strength of the cover plate and bearing plate (N), c Q: Shear strength of concrete (N), In the above formula (2), w τ U : Shear strength of the web of a steel beam reinforced by a doubler plate in a beam-column joint panel (N / mm 2 ) w A e : Effective cross-sectional area of the web of the steel beam reinforced by the doubler plate in the column-beam joint panel (mm 2 ) and w A e =( w t+0.8 d t)× c D ……(4) In the above formula (4), w t: thickness of the steel beam web in the column-beam joint (mm), d t: thickness of doubler plate (mm), c D: Depth of reinforced concrete column (mm) is.

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