Evaluation method of steel structure splicing joint

Abstract

The invention relates to a method for evaluating a steel structure splicing node, which comprises the following steps of: (a) after the steel structure splicing node is disassembled, acquiring defect information of the steel structure splicing node; (b) obtaining a correction factor of the rotational rigidity of the steel structure splicing node according to the defect information; (c) obtaining the theoretical shear stiffness and the theoretical bending stiffness of the steel structure splicing joint; (d) according to the correction factor, the theoretical shear stiffness and the theoretical bending stiffness, the actual rotational stiffness of the steel structure splicing joint is obtained; (e) after all the steel structure splicing joints are installed, the actual geometric morphology of the steel structure splicing joints is obtained; (f) the actual bearing capacity of the steel structure splicing joint is obtained according to the actual geometrical morphology and the actual rotational rigidity; (g) obtaining the design bearing capacity of the steel structure splicing joint; and (h) evaluating the reusability of the steel structure splicing joint according to the actual bearing capacity and the designed bearing capacity of the steel structure splicing joint.

Description

Technical Field

[0001] The invention relates to the technical field of assembled steel structures, and in particular to an evaluation method for steel structure splicing nodes. Background Art

[0002] The prefabricated steel structure system is a house unit or component made according to the unified and standard specifications of the Ministry of Construction. It is transported to the construction site for assembly after prefabrication in the factory. The steel structure has good mechanical processing performance and is easy to assemble. The assembled building has the characteristics of light weight, high strength, energy saving and environmental protection, fast construction speed and high degree of industrialization. The development of prefabricated steel structure is an urgent requirement for my country's green building and building industrialization. In recent years, in order to actively respond to the concept of green development, advocate energy-saving and environmentally friendly construction methods, and achieve sustainable development of the construction industry, the country has intensively issued policies for the construction industry from the strategic development level, encouraging and vigorously promoting prefabricated buildings. Steel column prefabricated assembly nodes are required for fixed connections between two steel columns in prefabricated buildings.

[0003] Steel structure splicing nodes are used for temporary factories and buildings, which need to be frequently disassembled and installed. If the steel structure does not have too many defects and damage after disassembly, these steel structures will generally be reused. Whether the existing steel structure splicing nodes can be reused depends entirely on the work experience of engineers, which is highly uncertain.

[0004] At the same time, the current specifications do not have a systematic and comprehensive evaluation method for steel structure splicing nodes. It only stipulates the deviation size of its appearance, and does not indicate how to deal with it when the deviation is greater than the specified value. For components that exceed the deviation specified in the specification, whether they can be reused needs to be evaluated according to a certain method. This patent proposes an evaluation method that quantifies the impact of node deviation on structural stress by establishing a relationship between the deviation size and structural performance. Summary of the invention

[0005] The purpose of the present invention is to provide a method for evaluating steel structure splicing nodes in order to overcome the defects of the above-mentioned prior art, so as to achieve scientific and effective evaluation of the reuse performance of steel structure splicing nodes.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A method for evaluating a steel structure splicing node comprises the following steps:

[0008] (a) obtaining defect information of the steel structure splicing node after the steel structure splicing node is disassembled;

[0009] (b) obtaining a correction factor for the rotational stiffness of the steel structure joint according to the defect information;

[0010] (c) Obtain the theoretical shear stiffness and theoretical bending stiffness of the steel structure joints;

[0011] (d) obtaining the actual rotational stiffness of the steel structure joint according to the correction factor, the theoretical shear stiffness and the theoretical bending stiffness;

[0012] (e) after all the steel structure splicing nodes are installed, obtaining the actual geometric shape of the steel structure splicing nodes;

[0013] (f) obtaining the actual bearing capacity of the steel structure joint according to the actual geometric shape and the actual rotational stiffness;

[0014] (g) obtaining the design bearing capacity of the steel structure joint;

[0015] (h) Evaluating the reusability of the steel structure splicing node based on the actual bearing capacity and design bearing capacity of the steel structure splicing node.

[0016] In one of the embodiments, in the step (a), the defect information includes defect type and defect size, the defect type includes convex defects and concave defects, and the defect size includes convex height and concave height.

[0017] In one embodiment, in the step (b), the following specific steps are included:

[0018] Obtaining the elastic stage rotational stiffness according to the defect type and defect size;

[0019] The correction factor is obtained according to the rotational stiffness in the elastic stage.

[0020] In one embodiment, in the step (c), the theoretical shear stiffness is obtained according to the following relationship:

[0021] R1=Gh1d c t c +Ed b A st cos 2 a sin a;

[0022] Where R1 is the theoretical shear stiffness, G is the shear modulus of the steel beam, h1 is the distance between the two flanges on the steel beam, and d c is the node domain width, t c is the thickness of the web of the steel beam, E is the elastic modulus of the steel beam, d b is the node domain height, A st is the total area of ​​the two oblique stiffening ribs, and a is the inclination angle of the oblique stiffening ribs.

[0023] In one embodiment, in the step (c), the theoretical bending stiffness is obtained according to the following relationship:

[0024]

[0025] Wherein, R2 is the theoretical bending stiffness, E is the elastic modulus of the steel beam, I e is the moment of inertia of the end plate, h1 is the distance between the two flanges on the steel beam, e f It is the distance from the center of the bolt of the extended part of the end plate to the upper flange of the steel beam.

[0026] In one embodiment, in step (c), the moment of inertia of the end plate is obtained according to the following relationship:

[0027]

[0028] Among them, I e is the moment of inertia of the end plate, b p is the width of the end plate, t p is the thickness of the end plate;

[0029] In one embodiment, in the step (d), the actual rotational stiffness is obtained according to the following relationship:

[0030]

[0031] Wherein, R is the actual rotational stiffness, η is the correction factor, the correction factor satisfies the following relationship: 0<η≤1, R1 is the theoretical shear stiffness, and R2 is the theoretical bending stiffness.

[0032] In one embodiment, in the step (g), the design bearing capacity is obtained according to the following relationship: Wherein, N′ is the design bearing capacity, is the stability coefficient of the steel beam, and the stability coefficient satisfies the following relationship: A is the cross-sectional area of ​​the steel beam, and f is the design tensile strength of the steel beam.

[0033] In one embodiment, in the step (h), the following specific steps are included:

[0034] Obtaining a structural stress ratio of the steel structure splicing node according to the actual bearing capacity and the designed bearing capacity of the steel structure splicing node;

[0035] The reusability of the steel structure splicing node is evaluated according to the structural stress ratio. When the structural stress ratio is less than or equal to 1, the steel structure splicing node is reusable, otherwise, the steel structure splicing node is not reusable.

[0036] In one embodiment, in the step (h), the structural stress ratio is obtained according to the following relationship:

[0037]

[0038] r is the structural stress ratio, N is the actual bearing capacity, and N′ is the designed bearing capacity.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. In the evaluation method of the steel structure splicing node, the actual rotational stiffness of the steel structure is first calculated according to the correction factor, the theoretical shear stiffness and the theoretical bending stiffness, and then the actual bearing capacity of the steel structure is calculated according to the actual geometric shape and the actual rotational stiffness. Finally, the reusability of the steel structure is evaluated according to the actual bearing capacity and the design bearing capacity. Since the defect information of the steel structure splicing node after use and the actual geometric shape of the steel structure splicing node after reuse are considered in the calculation process, the actual bearing capacity calculated is more real and reliable. Finally, the reusability evaluated according to the actual bearing capacity and the design bearing capacity also has a strong authenticity.

[0041] 2. In the evaluation method of the steel structure splicing node, the theoretical shear stiffness and theoretical bending stiffness can be calculated through the physical structure and characteristics of the steel beam and the end plate, and the actual size and shape of the steel structure are fully considered. The calculation results are true and reliable, avoiding the errors of traditional estimation methods.

[0042] 3. When calculating the actual rotational stiffness, the correction factor corrects the theoretical bending stiffness, improving the authenticity of the actual rotational stiffness.

[0043] 4. When evaluating the steel structure splicing nodes, first calculate the structural stress ratio of the steel structure splicing nodes according to the actual bearing capacity and design bearing capacity of the steel structure splicing nodes. The structural stress ratio is used to evaluate the reusability of the steel structure splicing nodes. That is, when the actual bearing capacity is less than or equal to the design bearing capacity, the steel structure splicing nodes are reusable, and when the actual bearing capacity is greater than the design bearing capacity, the steel structure splicing nodes are not reusable. The method is simple and is conducive to correctly judging the reusability of the steel structure splicing nodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a three-dimensional diagram of the steel structure splicing node in the present invention.

[0045] Figure 2 It is a cross-sectional view of the steel structure splicing node in the present invention.

[0046] Figure 3 It is a cross-sectional view of the steel beam in the present invention.

[0047] Figure 4 It is a top view of the steel beam in the present invention.

[0048] Figure 5 It is a schematic diagram of the concave defect of the steel structure splicing node in the present invention.

[0049] Figure 6 It is a schematic diagram of the convex defect of the steel structure splicing node in the present invention.

[0050] Figure 7 It is a schematic diagram of the node domain structure of the steel structure splicing node in the present invention.

[0051] Figure 8 It is a schematic diagram of the flow chart of the evaluation method of the steel structure splicing node in the present invention.

[0052] Figure numerals: 100, steel structure splicing node; 10, steel beam; 11, end plate; 111, first stiffening rib; 112, second stiffening rib; 12, connection hole; 13, web plate; 14, wing plate; 15, oblique stiffening rib; 20, high-strength bolt. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0054] A method for evaluating a steel structure splicing node 100 is described in detail below with reference to the accompanying drawings.

[0055] like Figures 1 to 4 As shown, in one embodiment, a steel structure splicing node 100 is provided, including two steel beams 10 and end plates 11 arranged on the steel beams 10, the end plates 11 of the two steel beams 10 are stacked, and a plurality of connecting holes 12 are provided on the end plates 11, and high-strength bolts 20 pass through the connecting holes 12 on the two end plates 11 in sequence to connect the two end plates 11 together.

[0056] Specifically, Figure 1 As shown, in one embodiment, the steel beam 10 is an I-beam 10, and the I-beam 10 includes a web 13 and two flanges 14 connected to both ends of the web 13, and the two flanges 14 are arranged opposite to each other along a first direction.

[0057] Furthermore, if Figure 4 As shown, in one embodiment, the length direction of the end plate 11 is parallel to the first direction, and the length of the end plate 11 is greater than the first direction dimension of the steel beam 10 .

[0058] Furthermore, if Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, in one embodiment, a portion of the end plate 11 extending out of the first steel beam 10 in the first direction is provided with a first stiffening rib 111 .

[0059] In this specific embodiment, two first stiffening ribs 111 are provided, which are respectively connected to the side walls of the two wing plates 14 of the steel beam 10 .

[0060] Specifically, Figure 4 As shown, in one embodiment, the width direction of the end plate 11 is the second direction, the second direction is perpendicular to the first direction, and the width of the end plate 11 is greater than the second direction dimension of the steel beam 10 .

[0061] Specifically, Figure 1 and Figure 4 As shown, in one embodiment, a portion of the end plate 11 extending out of the steel beam 10 in the second direction is provided with a second stiffening rib 112 .

[0062] Furthermore, if Figure 1 and Figure 4 As shown, in one embodiment, eight second stiffening ribs 112 are provided and are respectively connected to both ends of the flange 14 of the steel beam 10 .

[0063] Specifically, Figure 4 As shown, in one embodiment, the end plate 11 is an I-shaped end plate 11, and the arrangement direction of the I-shaped end plate 11 is the same as that of the I-shaped steel beam 10. At the same time, the shape of the end plate 11 matches the shape of the steel beam 10. The use of the I-shaped end plate 11 and the I-shaped steel beam 10 can reduce the amount of steel used while ensuring the stability of the connection node structure, and reduce the probability of damage to the end plate 11 during transportation and installation.

[0064] Specifically, Figure 4 As shown, in one embodiment, the connection holes 12 are distributed on the end plate 11 at both sides of the wing plate 14 , and a row of connection holes 12 along the width direction of the end plate 11 is respectively provided on both sides of the wing plate 14 .

[0065] like Figure 8 As shown, in one embodiment, a method for evaluating a steel structure splicing node 100 is provided, comprising the following steps:

[0066] (a) after the steel structure splicing node 100 is disassembled, obtaining defect information of the steel structure splicing node 100;

[0067] (b) obtaining a correction factor for the rotational stiffness of the steel structure joint 100 according to the defect information;

[0068] (c) obtaining the theoretical shear stiffness and theoretical bending stiffness of the steel structure splicing node 100;

[0069] (d) obtaining the actual rotational stiffness of the steel structure joint 100 according to the correction factor, the theoretical shear stiffness and the theoretical bending stiffness;

[0070] (e) after all the steel structure splicing nodes 100 are installed, obtaining the actual geometric shape of the steel structure splicing nodes 100;

[0071] (f) obtaining the actual bearing capacity of the steel structure joint 100 according to the actual geometric shape and the actual node rotation stiffness;

[0072] (g) obtaining the design bearing capacity of the steel structure joint 100;

[0073] (h) Evaluating the reusability of the steel structure splicing node 100 according to the actual bearing capacity and the designed bearing capacity of the steel structure splicing node 100.

[0074] In the evaluation method of the steel structure splicing node 100, the actual rotational stiffness of the steel structure is first calculated based on the correction factor, the theoretical shear stiffness and the theoretical bending stiffness, and then the actual bearing capacity of the steel structure is calculated through the actual geometric shape and the actual rotational stiffness. Finally, the reusability of the steel structure is evaluated based on the actual bearing capacity and the design bearing capacity. Since the defect information of the steel structure splicing node 100 after use and the actual geometric shape of the steel structure splicing node 100 after reuse are taken into account in the calculation process, the calculated actual bearing capacity is more real and reliable. Finally, the reusability evaluated based on the actual bearing capacity and the design bearing capacity also has a strong authenticity.

[0075] Specifically, in one embodiment, the actual geometric shape refers to the actual coordinates of the shape of the factory building. A real finite element model is established according to the actual geometric shape and the actual node rotation stiffness to calculate the actual bearing capacity of the steel structure splicing node 100.

[0076] Specifically, Figure 5 and Figure 6 As shown, in one embodiment, in the step (a), the defect information includes defect type and defect size, the defect type includes convex defects and concave defects, and the defect size includes convex height e1 and concave height e2.

[0077] In one embodiment, in the step (b), the following specific steps are included:

[0078] Obtaining the elastic stage rotational stiffness according to the defect type and defect size;

[0079] The correction factor is obtained according to the rotational stiffness in the elastic stage.

[0080] Furthermore, in one embodiment, the correction factor satisfies the following relationship:

[0081] When the defect type is a convex defect, when e1≤h / 300, the correction factor η is 1; when h / 300<e1≤h / 200, the correction factor η is 0.9; when h / 200<e1≤h / 100, the correction factor η is 0.8; when h / 100<e1≤h / 50, it is 0.7.

[0082] When the defect type is a concave defect and e2≤h / 300, the correction factor η is 1; when e2>h / 300, the correction factor η is 0.9. Wherein, h is the cross-sectional height of the steel beam 10, that is, the dimension along the first direction.

[0083] Specifically, Figure 7 As shown, in one embodiment, in the step (c), the theoretical shear stiffness is obtained according to the following relationship:

[0084] R1=Gh1d c t c +Ed b A st cos 2 a sin a;

[0085] Wherein, R1 is the theoretical shear stiffness, G is the shear modulus of the steel beam 10, h1 is the distance between the two flanges 14 on the steel beam 10, and d c is the node domain width, t c is the thickness of the web of the steel beam 10, E is the elastic modulus of the steel beam 10, d b is the node domain height, A st is the total area of ​​the two oblique stiffening ribs 15, and a is the inclination angle of the oblique stiffening rib 15.

[0086] The node domain is an area enclosed by the column, two webs and the end plate, the node domain width is the distance between the column and the end plate, excluding the thickness of the column and the end plate, and the node domain height is the distance between the two webs, excluding the thickness of the webs. Two oblique stiffening ribs 15 are provided between the two webs.

[0087] Specifically, in one embodiment, in the step (c), the theoretical bending stiffness is obtained according to the following relationship:

[0088]

[0089] Wherein, R2 is the theoretical bending stiffness, E is the elastic modulus of the steel beam 10, and I e is the moment of inertia of the end plate 11, h1 is the distance between the two flanges 14 on the steel beam 10, and e fIt is the distance from the center of the bolt of the extended part of the end plate 11 to the flange plate 14 on the steel beam 10.

[0090] Specifically, Figure 7 As shown, in one embodiment, in the step (c), the moment of inertia of the end plate 11 is obtained according to the following relationship:

[0091]

[0092] Among them, I e is the moment of inertia of the end plate 11, b p is the width of the end plate 11, t p is the thickness of the end plate 11;

[0093] In the evaluation method of the steel structure splicing node 100, the theoretical shear stiffness and the theoretical bending stiffness can be calculated through the physical structure and characteristics of the steel beam 10 and the end plate 11, and the actual size and shape of the steel structure are fully considered. The calculation results are true and reliable, avoiding the errors of traditional estimation methods.

[0094] Specifically, in one embodiment, in the step (d), the actual rotational stiffness is obtained according to the following relationship:

[0095]

[0096] Wherein, R is the actual rotational stiffness, η is the correction factor, and the correction factor satisfies the following relationship: 0<η≤1, R1 is the theoretical shear stiffness, and R2 is the theoretical bending stiffness. When calculating the actual rotational stiffness, the correction factor corrects the theoretical bending stiffness, thereby improving the authenticity of the actual rotational stiffness.

[0097] Specifically, in one embodiment, in the step (g), the design bearing capacity is obtained according to the following relationship: Wherein, N′ is the design bearing capacity, is the stability coefficient of the steel beam 10, and the stability coefficient satisfies the following relationship: A is the cross-sectional area of ​​the steel beam 10 (the cross-sectional area of ​​a component refers to the total area without deducting losses such as connection holes), and f is the designed tensile strength of the steel beam 10 .

[0098] In this specific embodiment, the value is generally in the range of 0 to 1 according to the slenderness ratio of the steel beam 10 , the yield strength of the steel beam 10 , and the cross-sectional shape classification and the specification.

[0099] In one embodiment, in the step (h), the following specific steps are included:

[0100] Obtaining a structural stress ratio of the steel structure splicing node 100 according to the actual bearing capacity and the designed bearing capacity of the steel structure splicing node 100;

[0101] The reusability of the steel structure splicing node 100 is evaluated according to the structural stress ratio. When the structural stress ratio is less than or equal to 1, the steel structure splicing node 100 is reusable, otherwise, the steel structure splicing node 100 is not reusable.

[0102] In one embodiment, in the step (h), the structural stress ratio is obtained according to the following relationship:

[0103]

[0104] r is the structural stress ratio, N is the actual bearing capacity, and N′ is the designed bearing capacity.

[0105] When evaluating the steel structure splicing node 100, the structural stress ratio of the steel structure splicing node 100 is first calculated according to the actual bearing capacity and the design bearing capacity of the steel structure splicing node 100. The structural stress ratio is used to evaluate the reusability of the steel structure splicing node 100, that is, when the actual bearing capacity is less than or equal to the design bearing capacity, the steel structure splicing node 100 is reusable, and when the actual bearing capacity is greater than the design bearing capacity, the steel structure splicing node 100 is not reusable. The method is simple and is conducive to correctly judging the reusability of the steel structure splicing node 100.

[0106] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0107] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0108] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0109] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0110] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0111] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for evaluating steel structure splicing nodes, characterized in that: The steps include: (a) obtaining defect information of the steel structure splicing node after the steel structure splicing node is disassembled; (b) obtaining a correction factor for the rotational stiffness of the steel structure joint according to the defect information; (c) Obtain the theoretical shear stiffness and theoretical bending stiffness of the steel structure joints; (d) obtaining the actual rotational stiffness of the steel structure joint according to the correction factor, the theoretical shear stiffness and the theoretical bending stiffness; (e) after all the steel structure splicing nodes are installed, obtaining the actual geometric shape of the steel structure splicing nodes; (f) obtaining the actual bearing capacity of the steel structure joint according to the actual geometric shape and the actual rotational stiffness; (g) obtaining the design bearing capacity of the steel structure joint; (h) Evaluating the reusability of the steel structure splicing node based on the actual bearing capacity and design bearing capacity of the steel structure splicing node.

2. The method for evaluating a steel structure joint according to claim 1, characterized in that: In the step (a), the defect information includes defect type and defect size, the defect type includes convex defects and concave defects, and the defect size includes convex height and concave height.

3. The method for evaluating a steel structure joint according to claim 2, characterized in that: In the step (b), the following specific steps are included: Obtaining the elastic stage rotational stiffness according to the defect type and defect size; The correction factor is obtained according to the rotational stiffness in the elastic stage.

4. The method for evaluating a steel structure joint according to claim 1, characterized in that: In the step (c), the theoretical shear stiffness is obtained according to the following relationship: R1=Gh1d c t c +Ed b A st cos 2 asina; Where R1 is the theoretical shear stiffness, G is the shear modulus of the steel beam, h1 is the distance between the two flanges on the steel beam, and d c is the node domain width, t c is the thickness of the web of the steel beam, E is the elastic modulus of the steel beam, d b is the node domain height, A st is the total area of ​​the two oblique stiffening ribs, and a is the inclination angle of the oblique stiffening ribs.

5. The method for evaluating a steel structure joint according to claim 1, characterized in that: In the step (c), the theoretical bending stiffness is obtained according to the following relationship: Wherein, R2 is the theoretical bending stiffness, E is the elastic modulus of the steel beam, I e is the moment of inertia of the end plate, h1 is the distance between the two flanges on the steel beam, e f It is the distance from the center of the bolt of the extended part of the end plate to the upper flange of the steel beam.

6. The method for evaluating a steel structure joint according to claim 5, characterized in that: In the step (c), the moment of inertia of the end plate is obtained according to the following relationship: Among them, I e is the moment of inertia of the end plate, b p is the width of the end plate, t p is the thickness of the end plate.

7. A method for evaluating a connection node according to claim 1, characterized in that: In the step (d), the actual rotational stiffness is obtained according to the following relationship: Wherein, R is the actual rotational stiffness, η is the correction factor, the correction factor satisfies the following relationship: 0<η≤1, R1 is the theoretical shear stiffness, and R2 is the theoretical bending stiffness.

8. A method for evaluating a connection node according to claim 1, characterized in that: In the step (g), the design bearing capacity is obtained according to the following relationship: Wherein, N′ is the design bearing capacity, is the stability coefficient of the steel beam, and the stability coefficient satisfies the following relationship: A is the cross-sectional area of ​​the steel beam, and f is the design tensile strength of the steel beam.

9. A method for evaluating a connection node according to claim 1, characterized in that: In the step (h), the following specific steps are included: Obtaining a structural stress ratio of the steel structure splicing node according to the actual bearing capacity and the designed bearing capacity of the steel structure splicing node; The reusability of the steel structure splicing node is evaluated according to the structural stress ratio. When the structural stress ratio is less than or equal to 1, the steel structure splicing node is reusable, otherwise, the steel structure splicing node is not reusable.

10. A method for evaluating a connection node according to claim 9, characterized in that: In the step (h), the structural stress ratio is obtained according to the following relationship: r is the structural stress ratio, N is the actual bearing capacity, and N′ is the designed bearing capacity.

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