Structure of column-beam joint

Abstract

To provide a structure of a column-beam connection having a beam made of an H-shaped steel rigidly connected to a column made of a rectangular steel pipe capable of realizing a non-diaphragm type in a simple configuration while restricting a weight of a structure from being increased.SOLUTION: In a structure of a column-beam connection having a beam made from an H-shaped steel connected rigidly to a column made of a rectangular steel pipe, no diaphragm is provided at least at one of a height to which an upper flange of the beam is fitted and a height to which a lower flange of the beam is fitted at the column, an intermediate part provided in the middle of the beam and having a predetermined width, a widening part provided at an end of the beam and having a larger width than that of the intermediate part, and a horizontal haunch part provided between the intermediate part and the widening part and formed so that a width extends gradually from the intermediate part to the widening part are provided at the flange fitted to the height where the diaphragm is not provided among the upper flange and the lower flange of the beam, and the forms of the column and the beam satisfy a predetermined relation.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a structure of a column-beam joint in which a beam made of an H-shaped steel is rigidly joined to a column made of a square steel pipe.

Background Art

[0002] Normally, a diaphragm is provided at the column-beam joint of a steel frame structure. When a bending moment acts from the beam to the column, the out-of-plane deformation generated in the column to which the beam is attached is suppressed by the diaphragm, and the rigidity of the entire framework is ensured.

[0003] The diaphragm forms mainly include three types: an internal diaphragm form, a continuous diaphragm form, and an external diaphragm form. The internal diaphragm form is a form in which a diaphragm is joined inside a column made of a steel pipe by electro-slag welding or the like. The continuous diaphragm form is a form in which columns are joined vertically so as to sandwich the diaphragm, and the diaphragm penetrates the inside and outside of the column. The external diaphragm form is a form in which a diaphragm is joined to the outer periphery of the column.

[0004] However, when providing a diaphragm at the column-beam joint, it is necessary to cut out a steel plate into the shape of the diaphragm and join it to the column by machine or manually, which causes problems such as an increase in the man-hours and costs required for constructing the column-beam joint.

[0005] Therefore, a non-diaphragm type column-beam joint in which the diaphragm is omitted has been proposed for the column-beam joint of a steel frame structure.

[0006] For example, Patent Document 1 discloses that a square steel pipe used for a column-beam joint core, which is a column-beam joint between a square steel pipe column and an H-shaped steel beam, is formed by assembling two hot-rolled angle steels into a square shape and welding them to each other, so that the column-beam joint is made into a non-diaphragm type.

[0007] In addition, Patent Document 2 discloses a structure of a column-beam joint in which a beam made of H-shaped steel is rigidly joined to the flange portion of a column made of H-shaped steel. By making the cross-sectional dimensions of the beam and the column satisfy a predetermined determination formula, the column-beam joint is made into a non-diaphragm type.

[0008] Furthermore, Patent Document 3 discloses a design method for setting an optimal plate thickness for a panel portion in a non-diaphragm construction method in which hot-formed steel pipes are used for a column portion and a panel portion, and the plate thickness of the panel portion is made thicker than the plate thickness of the column portion. The panel portion plate thickness, column outer dimension, beam width, and beam deflection satisfy predetermined conditions.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0010] However, in the structures of the column-beam joints disclosed in Patent Documents 1 and 3 above, even in the non-diaphragm type, in order to make the rigidity of the entire framework of the structure equivalent to the case where the column-beam joint has a diaphragm, the plate thickness of the panel portion to which the beam is attached is set to be larger than the plate thickness of the column to ensure the rigidity of the column-beam joint and the panel portion, that is, the column-beam joint.

[0011] Therefore, there is a problem that it is necessary to separately manufacture a panel portion having a plate thickness larger than the plate thickness of the column and join it to the column, increasing the man-hours and costs required for constructing the column-beam joint.

[0012] In addition, in the structure of the column-beam joint disclosed in Patent Document 2, not only the panel part to which the beam is attached, but also the plate thickness of the entire column is set to a uniformly large size. As a result, the weight of the H-shaped steel column increases as a whole, resulting in an inefficient structure and an increase in the construction cost of the entire structure.

[0013] An object of the present invention is to provide a structure of a column-beam joint in which a beam made of H-shaped steel is rigidly joined to a column made of square steel pipe, and which can realize a non-diaphragm type with a simple configuration while suppressing an increase in the weight of the structure.

Means for Solving the Problems

[0014] As a result of intensive studies on a reasonable structure of the column-beam joint in order to solve the above problems, the inventors of the present application have found the following matters.

[0015] That is, the inventors of the present application have noticed that in the conventional design method, even when the beam has a widened portion or a horizontal haunch portion, the rigidity of the beam has been calculated assuming that these widened portions or horizontal haunch portions do not exist, so the rigidity of the beam has been underestimated. Then, by providing a widened portion or a horizontal haunch portion in the beam and appropriately evaluating the improvement in the rigidity of the column-beam joint due to the provision of these widened portions or horizontal haunch portions, the diaphragm is omitted without increasing the plate thickness of the panel portion, and a reasonable structure of the column-beam joint is obtained. After further detailed consideration, the present invention was conceived.

[0016] The gist of the structure of the column-beam joint of the present invention is as follows.

[0017] [1] The structure of a column-beam joint where a beam made of H-shaped steel is rigidly joined to a column made of square steel pipe. In the column, a diaphragm is not provided at least at one of the height where the upper flange of the beam is attached and the height where the lower flange is attached. Among the upper flange and the lower flange of the beam, the flange attached at the height where the diaphragm is not provided has an intermediate portion provided in the middle of the beam and having a predetermined width, a widened portion provided at the end of the beam and having a width larger than that of the intermediate portion, and a horizontal haunch portion provided between the intermediate portion and the widened portion and formed such that the width gradually increases from the intermediate portion toward the widened portion. The shapes of the column and the beam are such that the outer dimension of the column is D c , the plate thickness of the column is t c , the depth of the beam is D b , the flange thickness of the beam is t f , the web thickness of the beam is t w , the width of the beam at the intermediate portion is B b , the width of the widened portion is B b1 , the length of the beam from the center to the end is l, the length of the widened portion of the beam is l1, the length of the horizontal haunch portion of the beam is (l2 - l1), the Young's modulus of the column and the beam is E, the shear modulus of elasticity of the column and the beam is G, the rigidity of the column-beam flange joint based on the shapes of the column and the beam when it is assumed that no diaphragm is provided at the height where the flange of the beam is attached is K n , the rigidity of the column-beam flange joint based on the shapes of the column and the beam without the widened portion when it is assumed that an internal diaphragm is provided at the height where the flange of the beam is attached is K i0 , the rigidity of the column-beam flange joint based on the shapes of the column and the beam with the widened portion when it is assumed that an internal diaphragm is provided at the height where the flange of the beam is attached is K i1 When set as such, the values δ calculated based on the following formulas (1), (2a), (2b), (3), (4) bn , δ jn , δ bi , δ ji are such that δ bn + δ jn < δ bi + δ jiThe structure of the column-beam joint is characterized by satisfying the relationship.

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[0018] According to the structure of the column-beam joint of the present invention, in the structure of the column-beam joint in which a beam made of H-shaped steel is rigidly joined to a column made of square steel pipe, while suppressing an increase in the weight of the structure, a non-diaphragm type can be realized with a simple configuration.

[0019] Specifically, by providing a widened portion on the flange at the end of the beam, the column is restrained, and the stress flowing from the beam to the column diffuses to the corner side of the column, thereby relaxing stress concentration, suppressing out-of-plane deformation of the column, and improving the rigidity of the column-beam joint and the entire structure having the same.

[0020] Also, by setting the shapes of the column and the beam so that the values δ bn , δ jn , δ bi , δ ji satisfy the relationship of δ bn + δ jn < δ bi + δ ji it is possible to surely ensure rigidity equal to or higher than that of the diaphragm-type column-beam joint even when the diaphragm is omitted without increasing the plate thickness of the panel portion.

[0021] As a result, compared with the structure of the diaphragm-type column-beam joint and the structure of the column-beam joint with an increased plate thickness of the panel part, the man-hours and costs for joining such as welding when constructing the column-beam joint can be reduced.

[0022] In addition, in a structure using a high-strength steel type, when adopting an internal diaphragm-type column-beam joint, since it is necessary to perform electro-slag welding with a large heat input when welding the internal diaphragm, the structure of the steel material may soften and the strength of the column-beam joint may be impaired. In contrast, the structure of the column-beam joint of the present invention can be manufactured by general welding with a low heat input, so even in a structure using a high-strength steel type, the possibility of the strength of the column-beam joint being impaired is small.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Mode for Carrying Out the Invention

[0024] An embodiment of the structure of the column-beam joint of the present invention will be described below with reference to the drawings.

[0025] First, with reference to FIGS. 1 to 5, the deformation occurring in the column-beam joint will be described.

[0026] A structure composed of a ramen structure in which a column and a beam are rigidly joined can be regarded as being configured by continuously connecting a cross-frame including a column-beam joint 1 in which a column 10 is rigidly joined to a beam 20 in the vertical and horizontal directions as shown in FIG. 1.

[0027] When a horizontal force such as an earthquake load or a wind load acts on such a structure, the bending moment generated in the beam becomes almost zero at the center of the beam and gradually increases from the center of the beam toward the end of the beam. Therefore, the bending moment acting from the beam 20 to the column 10 of the cross-frame shown in FIG. 1 can be regarded as being replaced by an example in which a concentrated load acts at the tip of the cantilever beam model shown in FIG. 2.

[0028] When a concentrated load acts at the tip of the cantilever beam model shown in FIG. 2, the displacement δ b +δ j (see FIG. 3) occurring at the tip of the beam is the sum of the component δ b (see FIG. 4) due to the bending deformation of the beam and the component δ j (see FIG. 5) due to the deformation of the column-beam joint.

[0029] Based on the above, an embodiment of the structure of the column-beam joint of the present invention will be described below. (First Embodiment) Figure 6 schematically shows the structure of the column-beam joint 1 of the present embodiment. Further, FIG. 7 shows a longitudinal sectional view of the structure of the column-beam joint 1. Furthermore, FIGS. 8(a) and 8(b) show the cross-sectional views taken along line A-A' and line B-B' of FIG. 6, respectively.

[0030] As shown in FIGS. 6 to 8, the structure of the column-beam joint 1 is configured such that a beam 21 made of an H-shaped steel is rigidly joined to a column 10 made of a square steel pipe. As shown in FIG. 7, no diaphragm is provided at the column 10 at either the height where the upper flange 21f of the beam 21 is attached or the height where the lower flange 21f of the beam 21 is attached.

[0031] As shown in FIG. 6, the upper flange 21f and the lower flange 21f of the beam 21 each have an intermediate portion 21f1, a horizontal haunch portion 21f2, and a widened portion 21f3. The intermediate portion 21f1 is provided in the middle of the beam 21 and has a predetermined width B b and the widened portion 21f3 is provided at the end of the beam 21 and has a width B larger than that of the intermediate portion 21f1 as shown in FIG. 8(b). b1 The horizontal haunch portion 21f2 is provided between the intermediate portion 21f1 and the widened portion 21f3 as shown in FIG. 6, and is formed such that the width gradually increases from the intermediate portion 21f1 toward the widened portion 21f3.

[0032] Here, the shapes of the column 10 and the beam 21, that is, the outer dimension D of the column 10 shown in FIGS. 6 to 8 c , the plate thickness t of the column 10 c , the beam depth D of the beam 21 b , the flange thickness t of the beam 21 f , the web thickness t of the beam 21 w , the length l from the center to the end of the beam 21 (i.e., the total length of the beam 21 is 2l), the length l1 of the widened portion 21f3 of the beam 21, and the length (l2 - l1) of the horizontal haunch portion 21f2 of the beam (i.e., the total length l2 of the length of the widened portion 21f3 and the length of the horizontal haunch portion 21f2) are based on the Young's modulus E of the column 10 and the beam 21, the shear elastic modulus G of the column 10 and the beam 21, and the rigidity K of the column-beam flange joint of the column-beam joint 1 based on the shapes of the column 10 and the beam 21 n、 Assuming that the inner diaphragm is provided at both the height where the upper flange 21f of the beam 21 is attached and the height where the lower flange 21f is attached, the rigidity of the column-beam flange joint of the column-beam joint based on the shapes of the column 10 and the beam 21 is K i1 、 Assuming that the inner diaphragm is provided at both the height where the upper flange 21f of the beam 21 is attached and the height where the lower flange 21f is attached, and that the upper flange 21f and the lower flange 21f of the beam 21 have only the intermediate portion 21f1 without the horizontal haunch portion 21f2 and the widened portion 21f3, the rigidity of the column-beam flange joint of the column-beam joint based on the shapes of the column 10 and the beam 21 is K i0 Then, the value δ calculated based on the following formulas (1), (2a), (2b), (3), and (4) bn 、 δ jn 、 δ bi 、 δ ji is, δ bn +δ jn <δ bi +δ ji is set to satisfy the relationship of

[0033] [Equation]

[0034] (When no diaphragm is provided at either the height where the upper flange of the beam is attached or the height where the lower flange is attached)

[0035] [Equation]

[0036] (When an inner diaphragm is provided at one of the height where the upper flange of the beam is attached and the height where the lower flange is attached, and no inner diaphragm is provided at the other)

[0037] [Equation]

[0038]

Mathematics

[0039]

Mathematics

[0040] Here,

Mathematics

[0041]

Mathematics

[0042]

Mathematics

[0043] b = I h -a·l1 [mm 4 c = 1 / a [1 / mm 3 d = -(2l + bc) / a [1 / mm 2 e = l 2 -bd [mm 2 Here, the rigidity K of the above column-beam flange joint n , K i0 , K i1 is a value appropriately set based on the shapes of the column 10 and the beam 21, and may be obtained by finite element analysis or the like, but for simplicity, it may also be calculated based on the regression formulas of the following equations (5a), (6a), and (6b).

[0044] K n = 43G·t c (t c / D c ) 1.13 ×(B b1 / D c ) 3 [mm 2 …(5a)​​​​ K i0 = 19G·t d (t c / D c ) 0.42 × (B b / D c ) 1.04 [mm 2 …(6a) K i1 = 19G·t d (t c / D c ) 0.42 × (B b1 / D c ) 1.04 [mm 2 …(6b) Here, t d = t f + 3 [mm] The above value δ bn is, as described above, the component due to the bending deformation of the beam among the displacements generated at the tip of the beam when a concentrated load acts on the tip of the cantilever beam model obtained by replacing the structure of the column-beam joint 1 of this embodiment with the corresponding cantilever beam model.

[0045] Also, the above value δ bi is the component due to the bending deformation of the beam among the displacements generated at the tip of the cantilever beam model obtained by replacing the structure of the inner diaphragm type column-beam joint corresponding to the structure of the column-beam joint 1 of this embodiment with the corresponding cantilever beam model.

[0046] Therefore, in the above equations (1) and (3), based on the beam deflection equation, the above values δ bn and δ bi are derived.

[0047] Note that the structure of the inner diaphragm type column-beam joint corresponding to the structure of the column-beam joint 1 of this embodiment means that in the structure of the column-beam joint 1, horizontal haunch portions 21f2 and widened portions 21f3 are not provided on the upper flange 21f and the lower flange 21f of the beam 21. Instead, at each of the height where the upper flange 21f is attached and the height where the lower flange 21f is attached, the thickness t d = tf It is provided with an inner diaphragm of +5 [mm].

[0048] Also, the above value δ jn As described above, the structure of the column-beam joint 1 of this embodiment is replaced with a corresponding cantilever beam model for evaluation. Among the displacements that occur at the tip of the beam when a concentrated load acts on the tip of this cantilever beam model, it is a component caused by the deformation of the column-beam joint (out-of-plane deformation of the column).

[0049] Also, the above value δ ji is obtained by replacing the structure of the inner diaphragm type column-beam joint corresponding to the structure of the column-beam joint 1 of this embodiment with a corresponding cantilever beam model for evaluation. Among the displacements that occur at the tip of this cantilever beam model, it is a component caused by the deformation of the column-beam joint (out-of-plane deformation of the column).

[0050] That is, the above relationship δ bn +δ jn <δ bi +δ ji defines the condition that the amount of deformation of the entire structure having the non-diaphragm type column-beam joint structure of the present invention is less than the amount of deformation of the entire structure having the corresponding inner diaphragm type column-beam joint.

[0051] In addition, in formulas (2a), (2b) and formula (4), the joint rigidity K n [N / mm] of the structure of the non-diaphragm type column-beam joint 1 of this embodiment, and the joint rigidity K i0 [N / mm] or K i1 [N / mm] of the structure of the corresponding inner diaphragm type column-beam joint, based on which the above values δ bn and δ bi are derived.

[0052] Specifically, for example, when a shear force of 1 [N] acts on the beam, the bending moment generated at the end of the beam is 1×l = l [N / mm]. Considering that the couple corresponding to this bending moment acts from the beam flange to the surface of the column, the magnitude of the couple acting on the surface of this column is l / (Db -t f ) [N], and the out-of-plane rigidity of the column in the axial direction of the beam flange material is derived as shown in the above equations (5a), (6a), and (6b). Therefore, the out-of-plane deformation δ of the column in the axial direction of the beam flange material cjn [mm] (when the inner diaphragm is not provided) and δ cji [mm] (when the inner diaphragm is provided) are derived as shown in the following equations (7) and (8), respectively.

[0053]

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[0054]

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[0055] From this, the displacement amount δ at the tip of the beam due to the deformation of the column-beam joint jn [mm / N] (when the inner diaphragm is not provided at either the height where the upper flange of the beam is attached or the height where the lower flange of the beam is attached), δ jn [mm / N] (when the diaphragm is provided at at least one of the height where the upper flange of the beam is attached and the height where the lower flange of the beam is attached), and δ ji [mm / N] are derived as shown in the above equations (2a), (2b), and (4), respectively.

[0056] Note that the values of the joint rigidities K n , K i0 , K i1 can be obtained by numerical analysis of the column-beam joint by the finite element method or by structural experiments on the column-beam joint. The above equations (5a), (6a), and (6b), which are the derivation formulas of the above K n , K i0 , K i1 are regression formulas obtained from the results of numerical analysis of the column-beam joint by the finite element method as described above.

[0057] According to the structure of the column-beam joint 1 of the present embodiment, in the structure of the column-beam joint 1 in which the beam 21 made of H-shaped steel is rigidly joined to the column 10 made of square steel pipe, a non-diaphragm type can be realized with a simple configuration while suppressing an increase in the weight of the structure.

[0058] Specifically, by providing the widened portion 21f3 on the flange 21f at the end of the beam 21, the column 10 is restrained, and the stress flowing from the beam 21 to the column 10 diffuses to the corner side of the column 10 to relieve stress concentration, thereby suppressing the out-of-plane deformation of the column 10 and improving the rigidity of the column-beam joint 1 and the entire structure having the same.

[0059] Further, the values δ bn , δ jn , δ bi , δ ji are such that δ bn + δ jn < δ bi + δ ji By setting the shapes of the column 10 and the beam 21 so as to satisfy the relationship, even if the diaphragm is omitted without increasing the plate thickness of the panel portion, the rigidity equal to or higher than that of the diaphragm-type column-beam joint can be surely ensured.

[0060] As a result, compared with the structure of the diaphragm-type column-beam joint and the structure of the column-beam joint with an increased plate thickness of the panel portion, the man-hours and costs associated with joining such as welding when constructing the column-beam joint can be reduced.

[0061] Further, in a structure using a high-strength steel type, when adopting an internal diaphragm type column-beam joint, since it is necessary to perform electro-slag welding with a large heat input when welding the internal diaphragm, the structure of the steel material softens and the strength of the column-beam joint may be impaired. On the other hand, since the structure of the column-beam joint 1 of the present embodiment can be manufactured by general welding with a low heat input, the possibility of impairing the strength of the column-beam joint is small even in a structure using a high-strength steel type. (Second Embodiment) Fig. 9 schematically shows the structure of the column-beam joint 2 of the present embodiment. Further, Fig. 10 shows a longitudinal sectional view of the column-beam joint 2. Furthermore, Figs. 8(a) to 8(c) show the A-A' sectional view, B-B' sectional view, and C-C' sectional view of Fig. 9, respectively.

[0062] As shown in Figs. 8 to 10, the structure of the column-beam joint 2 is basically the same as the structure of the column-beam joint 1 of the first embodiment. However, in the structure of the column-beam joint 2 of the present embodiment, as shown in Fig. 8(c), the width B of the flange of the widened portion 22f3 b1 is larger than the width B h and the plate thickness t of the flange of the widened portion 22f3 f is provided with an additional widened portion having a larger plate thickness. On the side surface of the column 10, an additional widened portion 22f4 having a length of l3 is provided between the widened portion 22f3 of the flange 22f of the beam 22, which is different from the structure of the column-beam joint 1 of the first embodiment. The width B of the flange of this additional widened portion 22f4 h and the plate thickness t f2 are set to be larger than the width B of the flange of the widened portion 22f3 b1 and the plate thickness t f .

[0063] In the structure of the column-beam joint 2 of the present embodiment, I and b to e in the above formula (1) are values obtained in the same manner as in the first embodiment, and I h and a are values obtained as follows. Based on the above formulas (1), (2a), (2b), (3), and (4), the values δ bn , δ jn , δ bi , δ ji are set so that they satisfy the relationship of δ bn +δ jn <δ bi +δ ji .

[0064]

Equation

[0065]

Equation

[0066] Also, in the structure of the column-beam joint 2 of the present embodiment, similar to the first embodiment, the rigidity K of the column-beam flange joint in the above formulas (2a), (2b), and (4) n , K i0 , K i1 is a value appropriately set based on the shapes of the column 10 and the beam 22, and may be obtained by finite element analysis or the like, or may be calculated based on a regression formula for simplicity. Among these, the value of K i0 can be calculated based on the regression formula of the above formula (6a) as in the first embodiment. Also, the values of K n , K i1 can be calculated based on the regression formulas of the following formulas (5b) and (6c), respectively, instead of the above formulas (5a) and (6b) in the first embodiment.

[0067] K n =43G·t c (t c / D c ) 1.13 ×(B h / D c ) 3 [mm 2 …(5b) K i1 =19G·t d (t c / D c ) 0.42 ×(B h / D c ) 1.04 [mm 2 …(6c) In this way, by providing the additional widened portion 22f4 in the portion of the widened portion 22f3 adjacent to the column 10, the rigidity of the structure of the column-beam joint 2 and the entire structure having the same can be further improved. (Third Embodiment) FIG. 11 schematically shows the structure of the column-beam joint 3 of the present embodiment. Also, FIG. 12 shows a longitudinal sectional view of the structure of the column-beam joint 3. Further, FIGS. 8(a) and 8(b) show the cross-sectional views taken along the lines A-A' and B-B' of FIG. 11, respectively.

[0068] As shown in FIGS. 8, 11, and 12, the structure of the column-beam joint 3 is basically the same as that of the column-beam joint 1 of the first embodiment. However, in the structure of the column-beam joint 3 of this embodiment, an inner diaphragm 30 is provided at the height where the upper flange 23t of the beam 23 is attached, and the upper flange 24t is not provided with a widened portion or a horizontal haunch portion, which is different from the structure of the column-beam joint 1 of the first embodiment.

[0069] In this way, by providing no diaphragm on either the height where the upper flange 24t of the beam 24 is attached or the height where the lower flange 24b is attached, and providing an inner diaphragm on the other, the structure of the column-beam joint 3 can be made more reasonable.

Example

[0070] Regarding the shear strength of the structure of the non-diaphragm type column-beam joint (invention example) of the present invention and the shear strength of the structure of the corresponding inner diaphragm type column-beam joint (comparative example), numerical analysis was performed by the finite element method and the two were compared.

[0071] For both the invention example and the comparative example, the assumed structural framework is as follows: the length of the column is 6000 mm, the length of the beam (2l) is 11350 mm (beam span 12000 mm), the size of the square steel pipe forming the column is □-650×65 [mm], and the size of the H-shaped steel forming the beam is H-750×325×22×75 [mm]. Also, for both the column and the beam, the steel type is 550 N-class steel and the yield strength is 497 N / mm 2 is assumed.

[0072] For the invention example, it is assumed that the length l1 of the widened portion of the beam and the length l2 of the horizontal haunch portion of the beam are 100 mm and 385 mm, respectively, and the width B of the widened portion b1 is 650 mm.

[0073] For the comparative example, no widened portion or horizontal haunch portion is provided as in the invention example. Instead, an inner diaphragm is provided, and its thickness t d is the same as the beam flange thickness t fIt was assumed to be 80 mm with three ranks of up - sizing of 75 mm.

[0074] Based on the above conditions, numerical analysis by the finite element method was performed for the inventive example and the comparative example, and the relationship between the load and the inter - layer deformation angle obtained as a result is shown in the graph of Fig. 13. As shown in this graph, it was confirmed that the structure of the column - beam joint of the inventive example has rigidity equal to or higher than that of the comparative example.

[0075] Also, for each of the inventive example and the comparative example, the values δ bn +δ jn and δ bi +δ ji shown as the ratio to the values obtained by the above numerical analysis by the finite element method were 0.98 and 1.05, respectively. As described above, the values δ bn +δ jn and δ bi +δ ji calculated based on the formulas (1) to (4) based on the regression formula are within an error of 5% with respect to the values obtained by numerical analysis, and it was confirmed that the above formulas (1) to (4) have sufficient accuracy.

Explanation of symbols

[0076] 1 - 3 Column - beam joints 10 Columns 21 - 23 Beams 21f, 22f, 23t, 23b Flanges 21f1, 22f1, 23b1 Intermediate parts 21f2, 22f2, 23b2 Horizontal haunch parts 21f3, 22f3, 23b3 Widening parts 22f4 Additional widening part D c Outer dimension of the column t c Plate thickness of the column D b Beam depth of the beam t f Flange thickness of the beam t w Web thickness of the beam B bWidth of the beam (at the middle part) B b1 Width of the widened part B h Width of the additional widened part l Length of the beam from the center to the end l1 Length of the widened part of the beam l2 Length of the horizontal haunch part of the beam E Young's modulus of the column and the beam G Shear modulus of the column and the beam

Claims

1. A structure of a column-beam joint where a beam made of H-shaped steel is rigidly joined to a column made of square steel pipe, wherein no diaphragm is provided at either the height where the upper flange of the beam is attached or the height where the lower flange of the beam is attached to the column, each of the upper flange and the lower flange of the beam has an intermediate portion provided in the middle of the beam and having a predetermined width, a widened portion provided at the end of the beam and having a width larger than that of the intermediate portion, and a horizontal haunch portion provided between the intermediate portion and the widened portion and formed such that the width gradually increases from the intermediate portion toward the widened portion, an additional widened portion having a width larger than the width of the flange of the widened portion and a plate thickness larger than the plate thickness of the flange of the widened portion is provided between the side surface of the column and the widened portion of the flange of the beam, The outer dimension D of the column c , the plate thickness t of the column c , the beam deflection D of the beam ｂ , the flange thickness t of the beam f , the web thickness t of the beam ｗ , the width B of the beam in the middle part b , the width B of the additional widened part h , the length l from the center to the end of the beam, the length l of the widened part of the beam 1 , and the length of the horizontal haunch part of the beam (l 2 - l 1 ) is characterized in that when the Young's modulus of the column and the beam is E and the shear elastic coefficient of the column and the beam is G, it is set to satisfy the relationship of the following formula (0). δ bn +δ jn <δ bi +δ ji ……(0) however, in the above formula (0), 【Number 1】 【Number 2】 【Mathematics 3】 【Number 4】 and in the above formulas (1), (2a), (3), (4), 【Number 5】 【Number 6】 【Number 7】 b = I h -a·l 1 [mm 4 ​ c = 1 / a [1 / mm 3 ​ d = -(2l + bc) / a [1 / mm 2 ​ e = l 2 -bd [mm 2 ​ K n = 43 G·t c (t c / D c ) 1.13 × (B h / D c ) 3 [mm 2 ] K i0 = 19 G·t d (t c / D c ) 0.42 × (B b / D c ) 1.04 [mm 2 ​ t d = t f + 3 [mm] it is as follows.

2. A structure of a column-beam joint where a beam made of H-shaped steel is rigidly joined to a column made of square steel pipe, wherein an inner diaphragm is provided at one of the height where the upper flange of the beam is attached and the height where the lower flange of the beam is attached to the column, and no diaphragm is provided at the other, among the upper flange and the lower flange of the beam, the flange attached at the height where no diaphragm is provided has an intermediate portion provided in the middle of the beam and having a predetermined width, a widened portion provided at the end of the beam and having a width larger than that of the intermediate portion, and a horizontal haunch portion provided between the intermediate portion and the widened portion and formed such that the width gradually increases from the intermediate portion toward the widened portion, an additional widened portion having a width larger than the width of the flange of the widened portion and a plate thickness larger than the plate thickness of the flange of the widened portion is provided between the side surface of the column and the widened portion of the flange of the beam, The outer dimension D of the column c the plate thickness t of the column c the beam deflection D of the beam ｂ the flange thickness t of the beam f the web thickness t of the beam ｗ the width B of the beam in the middle part b the width B of the additional widened part h the length l from the center to the end of the beam, the length l of the widened part of the beam 1 and the length of the horizontal haunch part of the beam (l 2 -l 1 ) are set so as to satisfy the relationship of the following formula (0), where E is the Young's modulus of the column and the beam, and G is the shear elastic coefficient of the column and the beam. A structure of a column-beam joint characterized by this. δ bn +δ jn <δ bi +δ ji ……(0) however, in the above formula (0), 【Number 8】 【Number 9】 【Number 10】 【Number 11】 and in the above formulas (1), (2b), (3), (4), 【Number 12】 【Number 13】 【Number 14】 b = I h -a·l 1 [mm 4 ​ c = 1 / a [1 / mm 3 ​ d = -(2l + bc) / a [1 / mm 2 ​ e = l 2 - bd [mm 2 ​ K n = 43 G·t c (t c / D c ) 1.13 × (Bh / Dc) 3 [mm 2 ​ K i1 = 19 G·t d (t c / D c ) 0.42 × (Bh / Dc) 1.04 [mm 2 ​ it is as follows.

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