Steel frame structure beam-column joint stiffening rib design method based on structural overall rigidity

Abstract

The invention discloses a steel frame structure beam column joint stiffening rib design method based on structural overall rigidity, and relates to the technical field of constructional engineering, and the method comprises the following steps: carrying out conventional structural design on a beam column; calculating a main structure index under the condition of complete rigid connection of the structural beam column; considering the actual rigidity of the beam-column joint to obtain a structural target rigidity index after rigidity weakening; through node finite element analysis, a performance curve of ring plate width-node rotational rigidity is obtained; carrying out refined modeling on beam-column nodes, and carrying out iterative calculation on the target rotational stiffness of the nodes; and substituting the performance curve to determine the width of the designed annular plate. By the adoption of the scheme, design is carried out according to the steps of the design method under set structural arrangement, the design width of the stiffening ring plate in the beam-column joint can be quantitatively determined, and on the premise that it is guaranteed that the overall rigidity of the structure meets the engineering requirement, the dead weight of the joint can be optimized, the material consumption can be reduced, and joint machining and construction installation are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of building engineering, and in particular to a design method for stiffening ribs of beam-column nodes of a steel frame structure based on overall structural stiffness. Background Art

[0002] The steel frame structure is a structural form that uses steel beams and columns as the main lateral force-resisting components to form a frame that bears all the loads of the house. Steel has the characteristics of high strength, light weight, and high rigidity, and is suitable for building structures with large spans and high heights. Because of its advantages such as strong spanning capacity, light weight, good seismic performance, fast construction speed, and natural conformity to assembly characteristics, the steel frame structure is widely used in high-rise buildings, such as exhibition halls, convention and exhibition centers and other large-span buildings, waiting halls and other public facilities and transportation buildings, and multi-story buildings in high-intensity areas.

[0003] The overall stiffness and bearing capacity of steel frame structures depend on the connection performance at the beam-column nodes. Existing calculation assumptions all use the beam-column rigid connection assumption, that is, there is no difference in translation and rotation between beams and columns at the nodes, and the degrees of freedom are fully coupled. However, the construction of the beam-column node is the key to determining whether the calculation assumption is reasonable and reliable. In actual engineering construction, it is difficult to achieve a completely rigid connection between beams and columns. Incompletely rigid nodes will cause the node stiffness to decrease, which in turn causes the overall stiffness of the structure to decrease, affecting the force safety of the structure.

[0004] In beam-column rigid joints, transverse stiffening ribs are usually set at the position of the column body facing the beam flange to transfer the internal force of the flange and strengthen the bending stiffness of the node domain to ensure the rigidity of the node. In actual engineering projects, with the emergence of more and more large-section columns, the transverse stiffening ribs of the column facing the beam flange usually adopt the structural form of a ring plate with a hole in the middle, which not only reduces weight and controls the amount of materials, but also facilitates the processing and welding of steel structures in the node area. At the same time, the holes in the ring plate can be used to lay equipment pipelines such as siphon water pipes. For steel tube concrete columns, it is a key approach to ensure the quality of concrete pouring. The setting thickness of the stiffening ring plate is usually equal to the thickness of the beam flange or slightly thicker by 1 to 2 mm, but there is no mature design regulation and design method for the quantitative value of its setting width. Summary of the invention

[0005] The present invention aims to solve the deficiencies of the prior art and to provide a design method for stiffening ribs in beam-column nodes of steel frame structures based on the overall stiffness of the structure. By adopting this scheme, under a given structural layout, the design is carried out according to the steps of the design method, and the design width of the stiffening ring plate in the beam-column node can be quantitatively determined. On the premise of ensuring that the overall stiffness of the structure meets the engineering requirements, the node deadweight can be optimized, the material consumption can be reduced, and the node processing and construction and installation are facilitated.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for designing stiffening ribs of beam-column joints of a steel frame structure based on overall structural stiffness comprises the following steps:

[0008] Carry out structural design according to the conventional design process to determine the arrangement of beam and column components and their cross-sectional parameters; the stiffening ribs are designed as ring plates;

[0009] In the overall structural design model, the horizontal load of the inverted triangle load pattern is applied along the floor height direction as the first working condition, and the vertical force is applied downward at the top of the column at the top of the structure as the second working condition. The main structural indicators under the condition of complete rigid connection between the structural beam and column are calculated; the main structural indicators include: the first-order structural period T 0 , the top horizontal deformation value δ under the working condition 0 , the linear buckling stability factor P under working condition 2 cr0 ;

[0010] Based on the main structural indicators and considering the actual stiffness of the beam-column joints, the target stiffness index of the structure after the stiffness is weakened is obtained;

[0011] Establish a finite element analysis model of the beam-column node, and obtain the performance curve of the ring plate width-node rotation stiffness through node finite element analysis;

[0012] In the overall structural design model, the beam-column nodes are refined and modeled, and based on working conditions 1 and 2, the node target rotation stiffness that meets the structural target stiffness index is iteratively calculated;

[0013] The node target rotational stiffness is substituted into the performance curve of the ring plate width-node rotational stiffness, and the minimum ring plate width is determined based on the intersection point.

[0014] For a further solution, the target stiffness index of the structure after stiffness reduction includes: T t =1.05T 0 , δ t =1.10δ 0 , P crt =0.9P cr0 .

[0015] In a further solution, the establishment of a finite element analysis model of the beam-column node and obtaining a performance curve of the ring plate width-node rotation stiffness through finite element analysis of the node also includes the following specific steps:

[0016] Model the structure according to the arrangement position of each component and its cross-sectional parameters;

[0017] After the geometric model is established, the model is meshed and assigned material properties;

[0018] Setting boundary conditions, wherein the boundary conditions include: constraining the top and bottom of the node model column, and the beam end is free and serves as the loading end;

[0019] Then the node rotation angle φ corresponding to the applied bending moment M is calculated j , and according to the formula K j =M / φ j Solve the node rotation stiffness K j ;

[0020] Take the width of the ring plate as a variable and repeat the above steps to perform iterative calculations;

[0021] According to the node rotation stiffness K j , and the performance curve of ring plate width-node rotation stiffness is obtained.

[0022] In a further embodiment, in the model, the total height of the steel column section is not less than twice the width of the steel column section;

[0023] The length of the steel beam section from the node end to its own free end shall not be less than the height of the steel beam section;

[0024] The ring plate is arranged opposite to the beam flange, and has the same thickness as the beam flange.

[0025] As a further solution, when establishing the finite element analysis model of the beam-column node, the multi-axial constitutive model of steel adopts the classical metal plasticity model, and the uniaxial constitutive relationship adopts the double-broken line model, where Et = 0.01E0, and the steel is simulated by S4R shell elements.

[0026] A further solution is to plot the performance curve of ring plate width-node rotation stiffness with K j0 =35EI / L as the preset calculation rotation stiffness, and 0.2 to 5 times K j0 Calculations and curve drawing are carried out within a certain range; where E is the elastic modulus of steel, I is the bending stiffness of the beam section, and L is the span of the beam section.

[0027] In a further solution, the iterative calculation based on working condition 1 and working condition 2 to obtain the node target rotation stiffness that meets the structural target stiffness index also includes the following specific steps:

[0028] Set the connection stiffness K j ';

[0029] Applying conditions 1 and 2, calculate the structural period T under different rotational stiffness j ' and the top horizontal deformation value δ corresponding to the working condition j ', Linear buckling stability coefficient P under working condition 2 crj ';

[0030] Finally, select the one that satisfies T j '≤T t ,δ j '≤δ t , P crj '≥P crt The connection stiffness K jt As the target rotation stiffness of the node.

[0031] In a further solution, the step of setting the connection stiffness includes: setting a connection unit between the beam end and the column section, the translational stiffness of the connection unit is infinite, and the rotational stiffness of the connection unit is set as the connection stiffness; or setting the stiffness release at the beam end, not releasing the translational stiffness, releasing the bending stiffness, and setting the stiffness value as the connection stiffness.

[0032] A further solution is to calculate the target rotation stiffness of the node that meets the target stiffness index of the structure, and the connection stiffness K j 'Can K j0 To start with, perform a trial calculation and use the T obtained from the trial calculation results. j ',δ j '、P crj 'With the target value T t ,δ t , P crt The relationship between K j ' and complete the iterative calculation; where K j0 =35EI / L.

[0033] A further solution is to round up the minimum ring plate width after determining it to obtain the final designed ring plate width.

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] The present invention provides a design method for stiffening ribs in beam-column nodes of a steel frame structure based on the overall stiffness of the structure. By adopting this scheme, under a given structural layout, the design is carried out according to the steps of the design method, and the design width of the stiffening ring plate in the beam-column node can be quantitatively determined. On the premise of ensuring that the overall stiffness of the structure meets the engineering requirements, the dead weight of the node can be optimized, the material consumption can be reduced, and the node processing and construction and installation are facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0037] Figure 1 A schematic diagram of loads for working condition 1 during overall structural analysis provided by the present invention;

[0038] Figure 2 A load schematic diagram of working condition 2 during the overall structural analysis provided by the present invention;

[0039] Figure 3 A schematic diagram of the axial side of the beam-column node analysis model provided by the present invention;

[0040] Figure 4 A cross-sectional schematic diagram of the beam-column node analysis model provided by the present invention;

[0041] Figure 5 A grid division diagram of the beam-column node analysis model provided by the present invention;

[0042] Figure 6 Schematic diagram of boundary conditions and moment loading of the beam-column node analysis model provided by the present invention;

[0043] Figure 7 The ring plate width-node rotation stiffness performance curve provided by the present invention;

[0044] Figure 8 A simplified schematic diagram of the beam-column calculation assumptions in the overall analysis model provided by the present invention;

[0045] Fig. 9 A schematic diagram for determining the minimum ring plate width provided by the present invention;

[0046] Fig.10 A flow chart of the design method provided by the present invention;

[0047] Fig.11 A performance curve diagram of ring plate width-node rotation stiffness in another embodiment provided by the present invention;

[0048] Fig.12 A schematic diagram of determining the minimum ring plate width in another embodiment provided by the present invention.

[0049] Marks and corresponding parts names in the attached drawings:

[0050] 1-Steel column, 2-Steel beam, 3-Ring plate. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0052] Embodiment 1: This embodiment 1 provides a steel frame structure beam-column node design method based on the overall structural stiffness, such as Figure 1-Figure 10 As shown, the following specific steps are included:

[0053] 1) First, the structural design is carried out according to the conventional design process to determine the structural layout and the cross-sectional dimensions of the components. In the overall structural design model, the horizontal load of the inverted triangle load pattern is applied along the floor height direction as the first working condition, such as Figure 1 As shown; vertical force is applied to the top of the column at the top of the structure as working condition 2, as shown Figure 2 As shown; then calculate the main structural indicators under the condition of complete rigid connection of structural beams and columns, among which the main structural indicators include: first-order structural period T 0 , the top horizontal deformation value δ under the working condition 0 , the linear buckling stability factor P under working condition 2 cr0 .

[0054] After considering the actual stiffness of the nodes, the overall stiffness of the structure will be weakened. The target stiffness index of the structure after the stiffness is weakened is set as follows: T t =1.05T 0 , δ t =1.10δ 0 , P crt =0.9P cr0 .

[0055] 2) Establish a finite element analysis model of typical nodes of steel structure beams and columns, such as Figure 3 As shown, a parametric analysis based on the ring plate width is performed, different node rotation stiffnesses are obtained based on different ring plate widths, and the performance curve of ring plate width-node rotation stiffness is drawn, as shown in Figure 7 shown.

[0056] The specific steps mainly include:

[0057] ① The cross-section of beams and columns is determined by the overall calculation of the project. The total height of the steel column 1 section in the model shall not be less than twice the width of the column section, and the length of the steel beam 2 section shall not be less than the height of the beam section from the node end.

[0058] ② The stiffening plate is set opposite to the beam flange, and its thickness is the same as that of the beam flange. The model is built according to the ring plate 3 with a hole in the middle. The width b of the ring plate 3 is used as a variable for iterative calculation, such as Figure 4 shown.

[0059] ③ The multiaxial constitutive model of steel adopts the classical metal plasticity model (mises yield criterion, related flow law, isotropic strengthening); the uniaxial constitutive relationship adopts the double-broken line model, where Et = 0.01E0, and the steel plate is simulated by S4R shell element.

[0060] ④ Such as Figure 5As shown in the figure, after the geometric model is established, the model is meshed and assigned material properties: the mesh size should be close to the thickness of the steel plate; the mesh should be encrypted within the range of twice the beam height outside the node area.

[0061] ⑤Finally, set the boundary conditions: constrain the top and bottom of the node model column, and the beam end is free and used as the loading end, such as Figure 6 shown.

[0062] ⑥ Calculate the node rotation angle φ under the corresponding bending moment j , according to the formula K j =M / φ j Solve the node rotation stiffness K j ;

[0063] ⑥ After obtaining the node rotation stiffness, use the ring plate width as the horizontal coordinate and the beam rotation stiffness as the vertical coordinate, and draw the performance curve according to the existing data points, such as Figure 7 shown.

[0064] ⑦ Due to the extremely large range of node rotation stiffness, it is recommended to use K j0 =35EI / L as the preset calculation rotation stiffness. The performance curve is drawn in the range of 0.2 to 5 times K j0 Range; where E is the elastic modulus of steel, I is the bending stiffness of the beam section, and L is the span of the beam section.

[0065] 3) In the overall structural design model, the beam-column rigid joints are modeled in detail, and the calculation assumptions are as follows: Figure 8 As shown, the translational degrees of freedom at the nodes of the coupled steel beam 2 and steel column 1 are set to the connection stiffness K j '; Apply the same working conditions 1 and 2 in step 1) to calculate the structural period T under different rotational stiffness j ' and the top horizontal deformation value δ' corresponding to the working condition 1, the linear buckling stability coefficient P under working condition 2 crj ', take the one that satisfies T j '≤T t ,δ j '≤δ t , P crj '≥P crt The connection stiffness K jt As the target rotation stiffness of the node.

[0066] The above steps also include: ① There are usually two methods in the software to achieve the setting of the connection stiffness of the rotational freedom: one is to set a connection unit between the beam end and the column segment, the translation stiffness of the connection unit is infinite, and the rotation stiffness of the connection unit is set as the connection stiffness; the other is to set the stiffness release at the beam end, not release the translation stiffness, release the bending stiffness, and set the stiffness value as the connection stiffness;

[0067] ② Since the range of node rotation stiffness is very large, calculate the connection stiffness K j It is recommended to use K j0 To start with, perform a trial calculation and use the T obtained from the trial calculation results. j ',δ j '、P crj 'With the target value T t ,δ t , P crt The relationship between K j 'adjust the value and complete the iterative trial calculation to reduce the workload, where K j0 =35EI / L.

[0068] 4) If Fig. 9 As shown, the node target rotation stiffness K is plotted in the performance curve in step 2). jt The horizontal horizontal line, and the horizontal abscissa b corresponding to the intersection of the performance curve min That is the minimum ring plate width, which is rounded up to get the designed ring plate width.

[0069] In the above design method, the stiffness requirement of the node for the specific structure is quantitatively proposed based on the actual calculation structure stiffness requirement, which is targeted and quantifiable. The design method uses the first-order natural vibration period T of the structure, the vertex displacement δ under the inverted triangle load mode, and the buckling stability factor P under the top vertical load. Cr As indicators to measure the overall stiffness of the structure, the changes of these three indicators at different node stiffnesses are used to measure the overall structural stiffness degradation caused by the nodes not being ideally rigidly connected but having rotational stiffness, and recommended control limits are proposed.

[0070] The above design method establishes the connection between the node stiffener and the node rotation stiffness, and the node stiffness under the specified width structure can be quantitatively obtained through finite element analysis.

[0071] Based on the above measures, an executable and easy-to-implement design method for the width of the middle column stiffener in the beam-column joint of the steel frame structure based on the overall stiffness of the structure was established.

[0072] In addition, the connection nodes between steel tube concrete columns and steel beams can also be analyzed. The main differences and key points are: steel tube concrete columns are composed of outer steel tubes and embedded concrete. In the steps of establishing the model, it is noted that the plastic damage model is used for the concrete material constitutive model, the concrete unit is simulated by C3D8R solid unit, the ring plate stiffener is embedded in the concrete by embedded region constraints, and the concrete and steel column side walls are in surface-to-surface contact: the normal contact adopts the hard contact model, and the tangential contact adopts the Coulomb friction mechanics model.

[0073] This patented method can also be used to analyze the steel column and steel beam connection nodes of the steel frame + core tube structure. The difference is that the preset target rotational stiffness value in the trial calculation process of steps 2) and 3) is adjusted to 15EI / L, which can improve the efficiency of the trial calculation analysis.

[0074] Embodiment 2: This embodiment 2 is an application example based on embodiment 1, such as Fig.11 and Fig.12 As shown, it is an application in a steel structure frame project.

[0075] 1. Complete the conventional design process in 3d3s software and determine the typical layout. The beam section is welded H-beam H1000X300X12X30, with a typical span of 13 meters.

[0076] 2. Calculate the first-order structural period T 0 =0.91S, working condition top side shift δ 0 =25mm, linear buckling stability factor P under working condition 2 cr0 =95.

[0077] 3. Set the structural target stiffness index to: T t =1.05x0.91=0.96s;δ t =1.10x25=27.5mm;P crt =0.9x95=85.5.

[0078] 4. Establish a finite element calculation model for the beam-column node, starting from the ring plate width b = 100mm, increase the ring plate width in steps of 50mm, calculate to the ring plate width b = 350mm, and obtain the corresponding node rotation stiffness K j , plot the ring plate width b-node rotation stiffness K j Performance curves such as Fig.11 shown.

[0079] 5. Set the end unit rotation stiffness release in the 3d3s software, set the stiffness of the i / j node (corresponding to the two ends) of the steel beam around the 3rd axis (strong axis, corresponding to the vertical bending moment direction), and initially estimate it according to 35EI / L=2.81e9kN·m / rad. The calculated stiffness index does not meet the structural target stiffness index, so increase the node stiffness for further trial calculation. When the calculated stiffness result meets the structural target stiffness index, the required node rotation stiffness is obtained to be 3.42e9kN·m / rad.

[0080] 6. As Fig.12 As shown, the rotation stiffness K of the node at the width b of the ring plate jDraw a horizontal line of the required node rotation stiffness 3.42e9kN·m / rad in the performance curve and determine the minimum ring plate width b corresponding to the intersection position min =165mm, the design rounds up and finally determines the ring plate width b to be 200mm.

[0081] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A design method for stiffening ribs at beam-column joints of steel frame structures based on overall structural stiffness, characterized in that: The following steps are involved: The structure is designed according to the conventional design process to determine the arrangement of beam and column components and their cross-sectional parameters; wherein the stiffening rib is designed as a ring plate (3); In the overall structural design model, the horizontal load of the inverted triangle load pattern is applied along the floor height direction as the first working condition, and the vertical force is applied downward at the top of the column at the top of the structure as the second working condition. The main structural indicators under the condition of complete rigid connection between the structural beam and column are calculated; the main structural indicators include: the first-order structural period T0, the top horizontal deformation value δ0 under the first working condition, and the linear buckling stability coefficient P under the second working condition. cr0 ; Based on the main structural indicators and considering the actual stiffness of the beam-column joints, the target stiffness index of the structure after the stiffness is weakened is obtained; Establish a finite element analysis model of the beam-column node, and obtain the performance curve of the ring plate width-node rotation stiffness through node finite element analysis; In the overall structural design model, the beam-column nodes are refined and modeled, and based on working conditions 1 and 2, the node target rotation stiffness that meets the structural target stiffness index is iteratively calculated; The node target rotational stiffness is substituted into the performance curve of the ring plate width-node rotational stiffness, and the minimum ring plate width is determined based on the intersection point.

2. A method for designing stiffening ribs for beam-column joints of a steel frame structure based on overall structural stiffness according to claim 1, characterized in that: The target stiffness indexes of the structure after stiffness reduction include: T t =1.05T0,δ t =1.10δ0,P crt =0.9P cr0 .

3. The method for designing stiffening ribs of beam-column joints of steel frame structures based on overall structural stiffness according to claim 1, characterized in that: The step of establishing a finite element analysis model of a beam-column node and obtaining a performance curve of ring plate width-node rotation stiffness through finite element analysis of the node also includes the following specific steps: Model the structure according to the arrangement position of each component and its cross-sectional parameters; After the geometric model is established, the model is meshed and assigned material properties; Setting boundary conditions, wherein the boundary conditions include: constraining the top and bottom of the node model column, and the beam end is free and serves as the loading end; Then the node rotation angle φ corresponding to the applied bending moment M is calculated j , and according to the formula K j =M / φ j Solve the node rotation stiffness K j ; The width of the ring plate (3) is taken as a variable, and the above steps are repeated to perform iterative calculations; According to the node rotation stiffness K j , and the performance curve of ring plate width-node rotation stiffness is obtained.

4. A method for designing stiffening ribs for beam-column joints of a steel frame structure based on overall structural stiffness according to claim 3, characterized in that: In the model, the total height of the cross section of the steel column (1) is not less than twice the width of the cross section of the steel column (1); The cross-sectional length of the steel beam (2) from the node end to its own free end is not less than the cross-sectional height of the steel beam (2); The ring plate (3) is arranged opposite to the beam flange and has the same thickness as the beam flange.

5. The method for designing stiffening ribs of beam-column joints of steel frame structures based on overall structural stiffness according to claim 3, characterized in that: When establishing the finite element analysis model of the beam-column node, the multi-axial constitutive model of steel adopts the classical metal plasticity model, the uniaxial constitutive relationship adopts the double-broken line model, where Et = 0.01E0, and the steel plate is simulated by S4R shell element.

6. A method for designing stiffening ribs for beam-column joints of a steel frame structure based on overall structural stiffness according to claim 3, characterized in that: When drawing the performance curve of ring plate width-node rotation stiffness, K j0 =35EI / L as the preset calculation rotation stiffness, and 0.2 to 5 times K j0 Calculations and curve drawing are carried out within a certain range; where E is the elastic modulus of steel, I is the bending stiffness of the beam section, and L is the span of the beam section.

7. The method for designing stiffening ribs of beam-column joints of steel frame structures based on overall structural stiffness according to claim 1, characterized in that: The iterative calculation based on working condition 1 and working condition 2 to obtain the node target rotation stiffness that meets the structural target stiffness index also includes the following specific steps: Set the connection stiffness K j '; Applying conditions 1 and 2, calculate the structural period T under different rotational stiffness j ' and the top horizontal deformation value δ corresponding to the working condition j ', Linear buckling stability coefficient P under working condition 2 crj '; Finally, select the one that satisfies T j '≤T t , δ j '≤δ t , P crj '≥P crt The connection stiffness K jt As the target rotation stiffness of the node.

8. A method for designing stiffening ribs for beam-column joints of a steel frame structure based on overall structural stiffness according to claim 7, characterized in that: The step of setting the connection stiffness includes: setting a connection unit between the beam end and the column section, the translation stiffness of the connection unit is infinite, and the rotation stiffness of the connection unit is set as the connection stiffness; or setting stiffness release at the beam end, not releasing the translation stiffness, releasing the bending stiffness, and setting the stiffness value as the connection stiffness.

9. The method for designing stiffening ribs of beam-column joints of steel frame structures based on overall structural stiffness according to claim 7, characterized in that: When calculating the target rotation stiffness of the node that meets the target stiffness index of the structure, the connection stiffness K j 'Can K j0 To start with, perform a trial calculation and use the T obtained from the trial calculation results. j ',δ j '、P crj 'With the target value T t , δ t , P crt The relationship between K j ' and complete the iterative calculation; where K j0 =35EI / L.

10. The method for designing stiffening ribs of beam-column joints of steel frame structures based on overall structural stiffness according to claim 1, characterized in that: After determining the minimum ring plate width, round it up to get the final designed ring plate width.

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