Joint evaluation method

Abstract

To provide a joint unit evaluation method capable of appropriately evaluating structural characteristics of a joint unit between a steel tube and a steel frame beam.SOLUTION: A joint unit evaluation method evaluates structural characteristics of a joint unit J between a square steel tube 22 composed of a joint plate 22A and a side plate 22B orthogonal to the joint plate 22A and a steel frame beam 24 joined to the joint plate 22A by using restraining effect by the side plate 22B and length of the square steel tube 22.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a bond evaluation method. [Background technology]

[0002] The following Patent Document 1 describes that the full plastic yield strength of a steel pipe in out-of-plane bending is evaluated by a formula derived from yield line theory.

[0003] On the other hand, Patent Document 2 below shows a column-beam joint structure in which a beam joint bracket (steel beam) is joined to a steel pipe. In this joint structure, the width of the steel beam is larger than the width of the steel pipe. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-115541 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-257159 Summary of the Invention [Problem to be solved by the invention]

[0005] The yield line theory described in the above Patent Document 1 makes it possible to evaluate the full plastic strength when the edge of a steel pipe to which a steel beam is joined bulges out along a hexagonal yield line.

[0006] On the other hand, when the width of the steel beam is large, as in Patent Document 2, a restraining effect occurs in the steel pipe due to the edge that intersects with the edge to which the steel beam is joined, which suppresses deformation of the steel pipe and may prevent the formation of a tortoiseshell-shaped yield line. Also, when the length of the steel pipe to which the steel beam is joined is short, the yield line may not fit within the edge to which the steel beam is joined, and the tortoiseshell-shaped yield line may not be formed.

[0007] In these cases, it is difficult to properly evaluate the structural characteristics of the joint between the steel pipe and the steel beam using the evaluation method shown in Patent Document 1, which assumes that the pipe will bulge out along a tortoiseshell-shaped yield line.

[0008] In consideration of the above, an object of the present invention is to provide a joint evaluation method that can appropriately evaluate the structural characteristics of a joint between a steel pipe and a steel beam. [Means for solving the problem]

[0009] The joint evaluation method of claim 1 evaluates the structural characteristics of a joint between a square steel pipe composed of a joint plate and a side plate perpendicular to the joint plate and a steel beam joined to the joint plate, The restraint effect of the side panel according to the overlap width or distance between the flange of the steel beam and the side panel The evaluation is performed using the length of the square steel pipe.

[0010] In the joint evaluation method of claim 1, the structural characteristics of the joint between a square steel pipe and a steel beam are evaluated using the restraint effect of the side plates that are perpendicular to the joint plate of the square steel pipe where the steel beam is joined. This makes it possible to appropriately evaluate the structural characteristics even when the width of the steel beam is larger than the width of the square steel pipe.

[0011] Furthermore, this joint evaluation method uses the length of the square steel pipe to evaluate the structural characteristics of the joint between the square steel pipe and the steel beam, which allows for appropriate evaluation of the structural characteristics even when the square steel pipe is short.

[0012] The joint evaluation method of claim 2 comprises: The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate and a steel beam joined to the joint plate are evaluated using the restraint effect of the side plate and the length of the square steel pipe, and The plastic strength as a structural characteristic is evaluated from the plastic strength in each of the following three yield modes when a tensile force acts on the steel beam. Yield mode 1: A yield mode in which the joint plate rises out of the plane and both the upper and lower ends of the yield line are formed within the joint plate. Yield mode 2: A yield mode in which the joint plate rises out of the plane and both the upper and lower ends of the yield line formed are not formed within the joint plate. Yield mode 3: A yield mode in which the joint plate rises out of the plane and one of the upper and lower ends of the yield line is formed within the joint plate, and the other is not formed within the joint plate.

[0013] The joint evaluation method of claim 2 allows for appropriate evaluation of plastic strength even when the width of the steel beam is larger than the width of the square steel pipe or when the length of the square steel pipe is short.

[0014] The joint evaluation method of claim 3 comprises: The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate and a steel beam joined to the joint plate are evaluated using the restraint effect of the side plate and the length of the square steel pipe, and The maximum strength as a structural characteristic is evaluated from the maximum strength in each of the following three ultimate destruction modes when a tensile force acts on the steel beam. Ultimate failure mode 1: Ultimate failure mode caused by cleavage failure between the joint plate and the side plate. Ultimate failure mode 2: Ultimate failure mode due to shear failure along the side panels of the joint panel. Ultimate failure mode 3: Ultimate failure mode caused by shear failure of the joint plate along the steel beam.

[0015] In the joint evaluation method of claim 3, even when the width of the steel beam is larger than the width of the square steel pipe or when the length of the square steel pipe is short, the maximum strength can be appropriately evaluated.

[0016] The joint evaluation method of claim 4 comprises: The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate and a steel beam joined to the joint plate are evaluated using the restraint effect of the side plate and the length of the square steel pipe, and The structural characteristic is the initial stiffness of the joint when a tensile force is applied to the steel beam, and the width of the steel beam is B b The width of the joint plate at the part where the steel beam is joined is B c , the length of the square steel pipe is L c As, B b / B c and L c / B c The estimation formula for the initial stiffness is derived using

[0017] In the joint evaluation method of claim 4, even when the width of the steel beam is larger than the width of the square steel pipe or when the length of the square steel pipe is short, the initial rigidity can be evaluated appropriately. [Effects of the Invention]

[0018] According to the present invention, the structural characteristics of a joint between a steel pipe and a steel beam can be appropriately evaluated. [Brief explanation of the drawings]

[0019] [Figure 1A] 1 is a perspective view showing a joint between a column in which a square steel pipe is embedded and a steel beam, to which the joint evaluation method of the present invention is applied. [Figure 1B] 1 is a perspective view showing a joint between a square steel pipe and a steel beam to which the joint evaluation method of the present invention is applied. [Figure 2A] This is an elevation view of a joint plate and a half elevation view of a side plate showing yield mode 1 for evaluating plastic strength in the joint evaluation method of the present invention. [Figure 2B] This is an elevation view of a joint plate and a half elevation view of a side plate showing yield mode 2 for evaluating plastic strength in the joint evaluation method of the present invention. [Figure 2C] This is an elevation view of a joint plate and a half elevation view of a side plate showing yield mode 3 for evaluating plastic strength in the joint evaluation method of the present invention. [Figure 3A] This is an elevation view of a joint board and a half elevation view of a side board showing ultimate failure mode 1 for evaluating maximum strength in the joint evaluation method of the present invention. [Figure 3B] This is an elevation view of a joint board and a half elevation view of a side board showing ultimate failure mode 2 for evaluating maximum strength in the joint evaluation method of the present invention. [Figure 3C] This is an elevation view of a joint board and a half elevation view of a side board showing ultimate failure mode 3 for evaluating maximum strength in the joint evaluation method of the present invention. [Figure 4] FIG. 1 is a perspective view showing an analytical model for evaluating initial stiffness in the joint evaluation method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a bond evaluation method according to an embodiment of the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in the various drawings are the same components. However, unless otherwise specified in the specification, each component is not limited to one, and multiple components may be present.

[0021] Furthermore, descriptions of overlapping configurations and symbols in each drawing may be omitted. Note that the present disclosure is not limited to the following embodiments, and may be implemented by making appropriate modifications, such as omitting configurations or replacing them with different configurations, within the scope of the purpose of the present disclosure.

[0022] <Joint part> 1A shows a joint 10 between a column 30 made of reinforced concrete (made of steel-reinforced concrete at the joint) and a steel beam 24. Four steel beams 24 are provided at the joint 10. Each steel beam 24 is joined to a respective side surface of the column 30, which is rectangular in plan view. One of the steel beams 24 (steel beam 24A) is positioned at a different height from the other steel beams 24.

[0023] As shown in FIG. 1B, each steel beam 24 is joined to a square steel pipe 22. This square steel pipe 22 is a joining member for the steel beams 24, embedded in the "joint" of the column 30, and is not embedded over the entire longitudinal length of the column 30. The square steel pipe 22 is filled with concrete while embedded in the column 30. The square steel pipe 22 may be a roll-formed product, or may be four plate materials assembled by welding.

[0024] In this specification, the member formed by this square steel pipe 22 and steel beam 24 is referred to as a joint member 20. The "joint" of the present invention refers to the joint J between the square steel pipe 22 and each steel beam 24 in the joint member 20.

[0025] At the joint 20, the beam widths of the steel beams 24A and 24B are made large in order to transmit axial force between the steel beam 24A, which has a different height from the other steel beams 24, and the steel beam 24B, which is arranged coaxially with the steel beam 24A.

[0026] Specifically, as shown in Fig. 2A, the steel beams 24A and 24B (hereinafter referred to as steel beams 24) overlap with the side plate 22B of the square steel pipe 22 when viewed from the axial direction of the steel beam 24. The side plate 22B is a plate in the square steel pipe 22 that is perpendicular to the joint plate 22A to which the steel beam 24 is joined.

[0027] 2A is a diagram that schematically shows the deformation of the square steel pipe 22 due to the tensile force acting on the square steel pipe 22 from the steel beam 24. In this figure, only the flange plates of the steel beam 24 that receive the tensile force are shown. On the other hand, the flange plates and webs of the steel beam 24 that receive the compressive force are not shown. The same applies to FIGS. 2B, 2C, and 3A to 3C.

[0028] Also, the beam width of steel beam 24 is B b , the width of the square steel pipe 22 is B c , the thickness of the side plate 22B is t c Then, the inequality (B c -2t c b ≦B c ) holds.

[0029] That is, the steel beams 24A and 24B have a larger beam width than at least the beams that do not "overlap" with the side panels 22B of the square steel pipes 22. Also, the steel beams 24A and 24B have a beam width (B c -2t c )The beam width is larger than the beams below.

[0030] ​Thus, in the joint J to which the "joint evaluation method" of the present invention is applied, the beam width of the steel beams 24A and 24B is larger than the width of the square steel pipe 22. In such a joint J, when evaluating the structural characteristics, it is preferable to take into account the restraint effect of the edge (side panel 22B) of the square steel pipe 22 where the steel beams 24A and 24B are joined (joint panel 22A).

[0031] Furthermore, at the joint J, the length of the square steel pipe 22 to which the steel beams 24A and 24B are joined is short (shorter than the length of the column 30). At such a joint J, it is preferable to take the length of the square steel pipe 22 into consideration when evaluating the structural characteristics.

[0032] The square steel pipe 22 does not necessarily have to be embedded in the column 30. For example, the square steel pipe 22 itself may form a column (CFT column). In addition, the "joint evaluation method" of the present invention, which will be described later, can be applied regardless of the length of the square steel pipe 22.

[0033] Furthermore, the steel beams 24A and 24B do not need to overlap with the side plates 22B of the square steel pipes 22, and the beam width (B c -2t c ) or less. In other words, the "joint evaluation method" of the present invention, which will be described later, can be applied regardless of the beam width of the steel beam 24 relative to the square steel pipe 22.

[0034] <Joint evaluation method> The "joint evaluation method" of the present invention is, for example, a method for evaluating the structural characteristics of the joint J between a square steel pipe 22 and a steel beam 24. Specifically, the "structural characteristics" are any of the "plastic strength," "maximum strength," and "initial stiffness" of the joint J when a tensile force acts on the steel beam 24.

[0035] According to the "joint evaluation method" of the present invention, the structural characteristics of the joint J can be appropriately evaluated even when the width of the steel beam 24 is larger than the width of the square steel pipe 22. Furthermore, the structural characteristics of the joint J can be appropriately evaluated even when the length of the square steel pipe 22 is short.

[0036] <Method for evaluating joints - Plastic strength> To evaluate the plastic strength of joint J, the plastic strength is evaluated in each of the yield modes 1, 2, and 3 shown below.

[0037] Yield mode 1: As shown in Figure 2A, this is a yield mode in which both the upper and lower ends of the yield line K1 formed by the joint plate 22A rising out of the plane are formed within the joint plate 22A. The yield line K1 is formed in a tortoiseshell shape.

[0038] Yield mode 2: As shown in Figure 2B, this is a yield mode in which the joint plate 22A bulges out of the plane, forming a yield line K2, and neither the upper nor lower end of the yield line K2 is formed within the joint plate 22A. Because the square steel pipe 22 is short (the distance from the flange of the steel beam 24 to the upper and lower ends of the square steel pipe 22 is short), the yield line K2 does not form a tortoiseshell shape.

[0039] Yield mode 3: As shown in Figure 2C, this is a yield mode in which one of the upper and lower ends (the lower end in this example) of the yield line K3 formed by the joint plate 22A rising out of the plane is formed within the joint plate 22A, and the other (the upper end in this example) is not formed within the joint plate 22A. Because the square steel pipe 22 is short (the distance from the flange of the steel beam 24 to the upper end of the square steel pipe 22 is short), the upper side of the yield line K3 does not form a tortoiseshell shape.

[0040] (Legend) The values ​​shown in the formulas in this specification represent the following.

[0041] M0=t c 2 σ cy / 4 Out-of-plane bending moment per unit length of joint plate 22A σ cy Yield strength of square steel pipe 22 σ by Yield strength of flange plates under tension in steel beams 24 σ u Tensile strength of square steel pipe 22 t c Thickness of joint board 22A and side board 22B tf Thickness of flange plate subjected to tension in steel beam 24 t r Flange plate thickness including welds B c Square steel pipe width 22 B b Flange plate width l c The length from the flange plate to the upper and lower end faces of the square steel pipe 22 l' c The length from the flange plate to the bottom end of the square steel pipe 22 (see Figure 2C) m Distance between the edge of the flange plate and the end of the square steel pipe 22 b c B c -2t c x1 The vertical distance between the maximum protruding part and the non-protruding part at the yield line K1 y1 The horizontal distance between the maximum protrusion and non-protrusion at the yield line K1 y2 The horizontal distance between the maximum protrusion and non-protrusion at the yield line K2 x3 The vertical distance between the maximum protrusion and non-protrusion at the yield line K3 y3 The horizontal distance between the maximum protrusion and non-protrusion at the yield line K3

[0042] (Surrender Mode 1) The plastic strength P1 of yield mode 1 shown in Figure 2A can be calculated from the balance between the amount of work due to the external force P and displacement δ, the plastic deformation due to out-of-plane bending of the yield line K in the joint plate 22A, and the internal energy estimated from the plastic deformation due to axial tension at the flange plate edge of the steel beam 24, as shown in the following equation (1):

[0043] Here, equation (2) can be derived by expanding equation (1) and eliminating δ. The value of x1 that minimizes the internal energy on the right-hand side of equation (2) can be obtained from equation (3). By substituting x1 obtained from equation (3) into equation (2), the plastic strength P1 in yield mode 1 can be calculated.

[0044]

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[0045]

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[0046]

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[0047] (Surrender Mode 2) The plastic strength P2 in yield mode 2 shown in Figure 2B is given by equation (4). The value of y2 that minimizes the internal energy on the right side of equation (2) is obtained by equation (5). By substituting y2 obtained by equation (5) into equation (4), the plastic strength P2 in yield mode 2 can be calculated.

[0048]

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[0049]

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[0050] (Surrender Mode 3) The plastic strength P3 in yield mode 3 shown in Figure 2C is given by equation (6). The value of x3 that minimizes the internal energy on the right side of equation (6) is obtained by equation (7). By substituting x3 obtained by equation (7) into equation (6), the plastic strength P3 in yield mode 3 can be calculated.

[0051]

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[0052]

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[0053] (Plastic strength of joint) Plastic strength P of joint J pcl is expressed by the following equation (8) using the plastic strengths P1, P2, and P3 calculated in the evaluation of each mode above.

[0054]

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[0055] In addition, P in equation (8) s is the increase in plastic strength due to the restraining effect of the side plate 22B, and is expressed by the following equation (9). s is a value that indicates the relationship between the width of the square steel pipe 22 and the width of the flange plate of the steel beam 24, and is expressed by equation (10). By substituting the values ​​obtained from equations (9) and (10) into equation (8), the plastic strength P of the joint J is calculated. pcl is calculated.

[0056]

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[0057]

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[0058] As explained above, the plastic strength P of the joint J pcl is evaluated using the restraining effect of the side plate 22B as shown in formula (8), and is evaluated using the length of the square steel pipe 22 as shown in formulas (4) and (6).

[0059] Specifically, in equation (8), the value P, which is the increment of the plastic strength due to the restraint effect of the side panel 22B, s Therefore, the plastic strength P of the joint J pcl It can be said that the evaluation is based on the restraining effect of the side plate 22B.

[0060] In addition, in the formulas (4) and (6), the length l from the flange plate of the steel beam 24 to the upper end face and the lower end face of the square steel pipe 22c Therefore, the maximum strength P of the joint J is mct It can be said that is evaluated using the length of the square steel pipe 22.

[0061] Thus, according to the joint evaluation method of the present invention, the plastic strength can be appropriately evaluated even when the width of the steel beam 24 is larger than the width of the square steel pipe 22 or when the length of the square steel pipe 22 is short.

[0062] <Joint evaluation method - maximum strength> To evaluate the maximum strength of joint J, the maximum strength is evaluated for each of the ultimate failure modes 1, 2, and 3 shown below.

[0063] Ultimate failure mode 1: As shown in Figure 3A, this is an ultimate failure mode caused by cleavage (separation) failure between the joint board 22A and the side board 22B. The fracture line L1 is a tensile fracture line formed in the side board 22B on both sides of the joint board 22A. The fracture line L1 is also formed in the side board 22B in the vertical direction along the joint board 22A.

[0064] Ultimate failure mode 2: As shown in Figure 3B, this is an ultimate failure mode caused by shear failure along the side panel 22B of the joint plate 22A. The fracture line L2 is a shear fracture line formed in the joint plate 22A on both sides of the flange plate of the steel beam 24. The fracture line L2 is also formed in the joint plate 22A in the vertical direction along the side panel 22B.

[0065] Ultimate failure mode 3: As shown in Figure 3C, this is an ultimate failure mode caused by shear failure of joint plate 22A along steel beam 24. Fracture line L3 is a shear fracture line formed on both sides of the flange plate of steel beam 24. Furthermore, fracture line L3 is formed along the edges of both ends of the flange plate.

[0066] (Final Destruction Mode 1) The maximum strength P1 of the ultimate fracture mode 1 shown in FIG. 3A is calculated from the tensile fracture strength of the side panel 22B as shown in the following formula (11). c +t r) is the length of the fracture line L1 taking into account the spread of tensile stress as shown in Figure 3A, and t c is the thickness of the side panel 22B. c +t r )t c is the cross-sectional area of ​​the side panel 22B that is subject to tensile fracture.

[0067]

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[0068] (Final Destruction Mode 2) The maximum strength P2 of the ultimate failure mode 2 shown in FIG. 3B is calculated from the shear fracture strength of the joint board 22A as shown in the following formula (12). p +t r ) is the length of the fracture line L2, which takes into account the spread of shear stress, as shown in Figure 3A, and t c is the thickness of the joint board 22A. In other words, (2x p +t r )t c is the cross-sectional area of ​​the joint board 22A that is shear-ruptured.

[0069]

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[0070] (Final Destruction Mode 3) The maximum strength P3 of the ultimate failure mode 3 shown in FIG. 3C is calculated from the shear fracture strength of the joint plate 22A as shown in the following formula (13). b +2(t c +y p +t r )-B c} is the length of the fracture line L3 along the edge of the width direction end of the flange plate of the steel beam 24, shown in FIG. 3C, where shear fracture is considered, and t c is the thickness of the joint board 22A. In other words, {B b +2(t c +y p +t r)-B c}t c is the cross-sectional area of ​​the joint board 22A that is shear-ruptured.

[0071]

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[0072] In addition, x in equation (12) p is the plastic strength P in equations (8) to (10). pcl The value of x (either x1 or x3) in the determined yield mode (any of yield modes 1 to 3). However, if the plastic strength is determined by yield mode 2, x p Let be x1.

[0073] Also, y in equation (13) p is the plastic strength P in equations (8) to (10). pcl The value of y (either y1, y2, or y3) in the determined yield mode (any of yield modes 1 to 3) is used. Note that y1 = 2x1 2 / B c , y3=2x3 2 / B c is.

[0074] In addition, x p is calculated using the following formula (14) using the x values ​​(x1, x2, x3), where x1 = x2. p is calculated by the following equation (15) using the y values ​​(y1, y2, y3).

[0075]

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[0076]

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[0077] Maximum strength P of joint J mctis expressed by the following equation (16) using the maximum strengths P1, P2, and P3 calculated in the evaluation of each mode above.

[0078]

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[0079] As explained above, the maximum strength P of the joint J mct is evaluated using the restraint effect of the side panel 22B as shown in ultimate failure modes 1 and 2, and is evaluated using the length of the square steel pipe 22 as shown in ultimate failure modes 2 and 3.

[0080] Specifically, the ultimate failure modes 1 and 2 are failure modes that occur due to the presence of the side panel 22B, and therefore the maximum strength P mct It can be said that the evaluation is based on the restraining effect of the side plate 22B.

[0081] Also, x used in final destruction modes 2 and 3 p and y p is calculated using values ​​x1 and x3 that are not greater than the length of the square steel pipe 22, so the maximum strength P of the joint J mct It can be said that is evaluated using the length of the square steel pipe 22.

[0082] In this way, the joint evaluation method of the present invention can appropriately evaluate the maximum strength even when the width of the steel beam 24 is larger than the width of the square steel pipe 22 or when the length of the square steel pipe 22 is short.

[0083] <Method for evaluating joints - initial stiffness> To evaluate the initial stiffness of joint J, an estimation formula for the initial stiffness of joint J is derived using finite element analysis (FEM analysis). The analytical model used is a 1 / 4 object model shown in Figure 4. In other words, the square steel pipe 22 is divided into four parts by the width-direction center line CL1 of the joint plate 22A and the width-direction center line CL2 of the side plate 22B, and one of these parts is used as the analysis object for the finite element analysis.

[0084] The analysis parameters are the width B of the square steel pipe 22 c , width-thickness ratio B of square steel pipe 22 c / t c , the length L of the square steel pipe 22 relative to the width of the square steel pipe 22 c / B c , the flange width B of the steel beam 24 relative to the width of the square steel pipe 22 b / B c , flange width thickness ratio B b / t b Five types are used:

[0085] The procedure for setting these parameters is as follows: c Set B c Based on this, B c / t c , L c / B c , B b / B c From t c , L c , B b Furthermore, the set B b Based on this, B b / t b From t b Set.

[0086] Each parameter is B c = 100 to 900 mm, 9 types in 100 mm increments, (B c / t c ) -1 =0.04~0.2, 5 types in 0.04 increments, L c / B c =1.0~3.0, 3 types in 1.0 increments, B b / B c = 0.2 to 1.0, 5 types in 0.2 increments, (B b / t b ) -1 = 0.04 to 0.2, and set five types in increments of 0.04, and perform FEM analysis for a total of 9 x 5 x 3 x 5 x 5 = 3375 cases. As a result, the initial stiffness of the joint is calculated as the analytical value (K fem ) is obtained as

[0087] In addition, these parameters and the analytical value of the initial stiffness (K fem ) and the estimated initial stiffness (K cal ) is derived as shown in the following equation (17). Equation (17) uses each parameter to calculate the analytical value (K fem ) as close as possible to the estimate (K cal ) is the formula for calculating

[0088] To derive equation (17), first, K fem Check whether there is a certain correlation between the parameters and the parameter ratio, and use an approximate formula using the correlated parameters to calculate K fem Then, the coefficients used in the approximation formula are checked to see if they have a correlation with the parameters, and an approximation formula is established. By repeating the same process, formula (17) is derived.

[0089]

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[0090] As explained above, the initial stiffness K of the joint J cal is evaluated using the restraining effect of the side plate 22B as shown in equation (17), and is evaluated using the length of the square steel pipe 22 as shown in the parameters of the FEM analysis.

[0091] Specifically, since Bb / Bc (width of steel beam 24 / width of square steel pipe 22) is used in equation (17), the initial stiffness K of joint J is cal It can be said that the evaluation is based on the restraining effect of the side plate 22B.

[0092] In addition, the length L of the square steel pipe 22 is used as a parameter for FEM analysis. c Since the initial stiffness K of the joint J is cal It can be said that is evaluated using the length of the square steel pipe 22.

[0093] In this way, the joint evaluation method of the present invention can appropriately evaluate the initial rigidity even when the width of the steel beam 24 is larger than the width of the square steel pipe 22 or when the length of the square steel pipe 22 is short. [Explanation of symbols]

[0094] 22 Square steel pipe 22A Joint board 22B Side plate 24 Steel beams J joint

Claims

1. A joint evaluation method that evaluates the structural characteristics of a joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate, and a steel beam joined to the joint plate, using the restraint effect of the side plate depending on the overlap width or distance between the flange of the steel beam and the side plate and the length of the square steel pipe.

2. The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate, and a steel beam joined to the joint plate are evaluated using the restraining effect of the side plate and the length of the square steel pipe, and A joint evaluation method for evaluating the plastic strength as a structural characteristic from the plastic strength in each of the following three yield modes when a tensile force acts on the steel beam: Yield mode 1: A yield mode in which the joint plate rises out of the plane and both the upper and lower ends of the yield line are formed within the joint plate. Yield mode 2: A yield mode in which the joint plate rises out of the plane and both the upper and lower ends of the yield line formed are not formed within the joint plate. Yield mode 3: A yield mode in which the joint plate rises out of the plane to form a yield line, one of the upper and lower ends of which is formed within the joint plate, and the other is not formed within the joint plate.

3. The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate, and a steel beam joined to the joint plate are evaluated using the restraining effect of the side plate and the length of the square steel pipe, and A joint evaluation method for evaluating the maximum strength as a structural characteristic from the maximum strength in each of the following three ultimate failure modes when a tensile force acts on the steel beam: Ultimate failure mode 1: Ultimate failure mode caused by cleavage failure between the joint plate and the side plate. Ultimate failure mode 2: Ultimate failure mode due to shear failure along the side panels of the joint panel. Ultimate failure mode 3: Ultimate failure mode due to shear failure of the joint plate along the steel beam.

4. The structural characteristics of the joint between a square steel pipe consisting of a joint plate and a side plate perpendicular to the joint plate, and a steel beam joined to the joint plate are evaluated using the restraining effect of the side plate and the length of the square steel pipe, and the structural characteristic is the initial rigidity of the joint when a tensile force is applied to the steel beam, The width of the steel beam is B b The width of the joint plate at the part where the steel beam is joined is B c , the length of the square steel pipe is L c As, B b / B c and L c / B c and deriving an estimation formula for the initial stiffness using the above formula.

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