Method for correcting calculation formula of local pressure bearing capacity of steel beam web

Abstract

The invention belongs to the technical field of bridge engineering, and aims to eliminate the problem of systematic underestimation of web bearing capacity under the condition of standard effective loading length. The invention provides a method for correcting a local pressure bearing capacity calculation formula of a steel beam web, which comprises the following steps of: identifying and determining a key parameter ratio and an engineering application range thereof by carrying out sensitivity parameter analysis on a bending reduction coefficient; on the basis of the reference engineering case, fixed values are taken from part of parameters, and other geometric quantities are inversely calculated; based on a preset variable sequence, finite element models are established in Abaqus in batches, and the ultimate bearing capacity and the flange longitudinal stress level of each model are extracted; the standard calculation value is corrected according to a finite element result, the corrected ultimate bearing capacity of the steel beam web is calculated, and a corrected bending reduction coefficient is obtained accordingly; and finally, fitting a corrected formula about the regularized slenderness ratio on the correction coefficient by taking the specification parameter as an independent variable to obtain an expression capable of directly replacing the original specification. The method can significantly improve the calculation precision.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, specifically relating to a method for correcting the calculation formula of the local compressive bearing capacity of the web of a steel beam. Background Technology

[0002] In the field of structural engineering, a relatively mature theoretical system has been developed for the stress mechanism of I-beams under localized pressure after decades of research. Among them, the European standard EN 1993-1-5, due to its complete system and wide application, has long been used as the standard method for assessing the localized bearing resistance of the web. This standard introduces a buckling reduction factor. The yield strength of the material is reduced, and the spacing of the transverse stiffeners is used as a reference. as the effective length The criteria for determining the relationship between densely stiffened ribs and other conditions. The standard stipulates that when the calculated... Exceeding the rib spacing At that time, it should be intercepted to The values ​​are set to ensure the conservatism and security of the calculations.

[0003] However, both engineering practice and numerical research show that, regardless of and Due to the relative size of the web plates, European standards show significant deviations in their predictions of the ultimate bearing capacity. The formula shows a significant deviation, indicating a systematic underestimation of the web bearing capacity; when the stiffeners are densely arranged (i.e., When the European code predicted a decrease in web ultimate bearing capacity, the results showed a trend contrary to reality: as the rib spacing decreased, the web ultimate bearing capacity actually decreased, which is clearly inconsistent with mechanical principles and experimental observations. Especially in long-span steel box girder bridges, to meet overall stiffness and torsional resistance requirements, the web typically uses denser transverse stiffeners. In this case, the actual local bearing capacity of the structure does not decrease with the decrease in rib spacing, but rather increases due to the code's provisions on... The upper limit constraint leads to an overly conservative underestimation of the bearing capacity calculation results.

[0004] To address this limitation, scholars have proposed a modified model that describes the complete yielding stage of the web and the residual strength stage of the flange separately, and provides these parameters in the original code. Based on the resistance, a correction factor is introduced to compensate for the local stability performance under the condition of dense stiffeners. Although this method achieves more reasonable prediction results in most I-beam conditions, it only corrects the case where the effective length is equal to or exceeds the stiffener spacing, and does not fundamentally improve the European standard. Scope of application. Summary of the Invention In order to solve at least one of the above-mentioned technical problems in the prior art, the present invention provides a method for correcting the calculation formula of the local compressive bearing capacity of the web of a steel beam.

[0005] This invention is achieved using the following technical solution: a method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam, comprising the following steps: Perform buckling reduction coefficient Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The ratio of key parameters; the buckling reduction coefficient Used to correct the calculation formula for the local compressive bearing capacity of the web of steel beams; Based on engineering experience and surveys of actual bridge parameters, determine The range of the key parameter ratios is defined; and values ​​are gradually taken at equal steps within the engineering adaptation range to generate a variable sequence of corresponding key parameter ratios. Establish A finite element model of a steel box girder, wherein the number of finite element models is... for The product of the number of variables in the variable sequence of key parameter ratios; in the finite element simulation, one parameter of one of the key parameter ratios is set as a constant value, and the other parameter is used as a variable. The range of values ​​of the variable is inferred by the constant value and the range of the key parameter ratio. At the same time, other key parameter ratios and other geometric parameter ratios related to the buckling reduction coefficient are set as constant values. The above parameters are used as inputs to the finite element model. Obtained through finite element analysis Numerical solutions of the ultimate bearing capacity for each finite element model And extract the longitudinal stress level of the flange. ; Based on the results of finite element calculations, The local compressive bearing capacity of the web of the steel beam corresponding to each finite element model is corrected; The corrected buckling reduction factor is calculated based on the corrected local compressive bearing capacity of the steel beam web. ; Calculate the regularized slenderness ratio for each finite element model, and fit the corrected buckling reduction coefficient related to the regularized slenderness ratio. The expression; Based on the modified buckling reduction coefficient Replace the buckling reduction factor in the formula for calculating the local compressive bearing capacity of the web of a steel beam with the expression. This is to correct the calculation formula for the local compressive bearing capacity of the web of steel beams.

[0006] Preferably, the buckling reduction coefficient is calculated. Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The steps for calculating the ratio of each key parameter are as follows: The ratios of several geometric parameters related to the local compressive bearing capacity of the steel beam web were selected as analytical variables. Using the ratio of geometric parameters as the independent variable, the buckling reduction coefficient Plot the relationship curve for the dependent variable; By observing the influence of changes in the ratios of various geometric parameters on the slope of the relationship curve, the effect of different ratios of geometric parameters on the buckling reduction coefficient is quantitatively assessed. Sensitivity to identify the buckling reduction coefficient Significant impact The ratio of key parameters.

[0007] Preferably, the geometric parameters include loading length, flange thickness, flange yield strength, flange width, web height, regularized slenderness ratio, and critical buckling load.

[0008] Preferably, based on the results of finite element calculations, for The formula for correcting the local compressive bearing capacity of the steel beam web corresponding to the finite element model is as follows: In the formula, This refers to the corrected local compressive bearing capacity of the steel beam web. Reserve for post-buckling; For the corrected flange stress ratio, , They are external hinges and internal hinge The corrected flange stress ratio at the location; All of the following parameters are constant values. This refers to the length of the transverse stiffening rib; The effective load length; Web thickness; The width of the flange; For flange thickness; The flange yield strength; The web height; The loading length.

[0009] Preferably, the corrected buckling reduction factor is calculated based on the corrected local compressive bearing capacity of the steel beam web. The formula is as follows: In the formula, For yield load, This is the partial factor, with an empirical value of 1.0.

[0010] Preferably, the corrected buckling reduction coefficient related to the regularized slenderness ratio The expression is: In the formula, To regularize the slenderness ratio.

[0011] Preferably, the method for extracting the ultimate bearing capacity of the finite element model is as follows: In the finite element model, the point of application of the load is coupled with the loading area for constraint. Vertical loads are applied at the point of application using the arc-length method, and the maximum deflection of the upper flange is controlled. The finite element model is calculated, and the load-displacement curves at the points of application are extracted. The peak value of the load-displacement curve or the load corresponding to the occurrence of significant softening is the numerical solution of the ultimate bearing capacity obtained by the finite element method. .

[0012] Preferably, the longitudinal stress level of the flange is extracted. The steps include: Determine the analysis step corresponding to the ultimate bearing capacity based on the obtained load-displacement curve; The stress field is read in the X direction of the structural coordinate system in the result file of this analysis step; The arithmetic mean of the stress along the Z-direction path of the upper flange at a distance of 1 cm from the edge of the loading block in the stress field is taken as the longitudinal stress level of the flange. .

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a revised method for calculating the local compressive bearing capacity of the web of steel beams. While retaining the calculation system of yield load and regularized slenderness ratio in European standards, it proposes a revised design method for calculating the buckling reduction coefficient. This method not only inherits the theoretical framework of previous research but also incorporates extensive numerical simulation and experimental results. The buckling reduction coefficient under certain conditions was systematically corrected, enabling the predicted value in the code to more closely approximate the actual load-bearing capacity and significantly reducing the deviation between theoretical calculations and engineering tests. This method addresses the dual shortcomings of the original code—unsafe predictions under densely stiffened rib conditions and overly conservative predictions under conventional conditions—by quantifying the coupling effect of the web width-to-height ratio, loading length ratio, and height-to-thickness ratio, which are unique parameters of steel box girders.

[0014] Specifically, this method involves adjusting the buckling reduction coefficient. Perform sensitivity parameter analysis to identify and determine the ratios of several key parameters (e.g.) / , / , / ) and its engineering application scope; based on reference engineering cases, certain parameters are set and other geometric quantities are calculated in reverse; based on the preset variable sequence, finite element models are built in batches in Abaqus and the ultimate bearing capacity and longitudinal stress level of the flange of each model are extracted; the standard calculation values ​​are corrected based on the finite element results, the corrected ultimate bearing capacity of the steel beam web is calculated, and the corrected buckling reduction coefficient is obtained from it; finally, the standard parameters (such as regularized slenderness ratio) are used to calculate the ultimate bearing capacity of the steel beam web and the corrected buckling reduction coefficient. Fitting the correction coefficients with ) as independent variables The revised formula for regularized slenderness ratio yields an expression that can directly replace the original specification.

[0015] This invention can significantly improve calculation accuracy, providing a reliable basis for the web stability design and safety control of steel box girder launching construction, avoiding the large number of tests or simulations previously required in this type of design, and has the advantages of simple calculation, time-saving, labor-saving and low cost. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the algorithm of the present invention; Figure 2 This is the invention / and Sensitivity analysis of parameters to buckling reduction coefficient; Figure 3 This is a schematic diagram of the finite element model of the present invention; Figure 4 This is a schematic diagram of the load-displacement curve at the point of application extracted from the finite element simulation of this invention; Figure 5 The calculation method in the background technology / and Relationship diagram; Figure 6 The calculation correction method of this invention is based on the specification. A graph showing the buckling reduction coefficient obtained after adjusting the calculation method. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should fall within the scope of the technical content disclosed in the present invention. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0020] This invention provides an embodiment: like Figures 1 to 6 As shown, a method for correcting the calculation formula for the local compressive bearing capacity of steel beam webs is proposed, which modifies the buckling reduction coefficient in the calculation formula for the local compressive bearing capacity of steel beam webs in the European standard EN1993-1-5. The following formula, after modification, is the bearing capacity calculation formula in the standard: In the formula, To standardize the design of local pressure bearing capacity, The buckling reduction coefficient, For yield load, This is the partial factor, with an empirical value of 1.0. The web yield strength is... For the effective load length, Web thickness It is worth noting that, in the European standard EN 1993-1-5, the effective calculation range only includes the effective load length. Less than or equal to the spacing of the transverse stiffeners When exceeding When calculating the value, the modified formula proposed by other scholars for the code is adopted, that is, the post-buckling reserve is superimposed on the original ultimate bearing capacity: The post-buckling reserve is the result of taking into account the bearing capacity of the flange on the web.

[0021] The research results indicate that the calculation method for the ultimate bearing capacity of the web of a locally compressed steel box girder in EN 1993-1-5 contains significant errors. Clearly, the calculation formula in EN 1993-1-5 is overly conservative in calculating the ultimate bearing capacity of the web of a steel box girder subjected to localized compression loads. Particularly noteworthy is the special case where localized voiding of the support blocks occurs during the jacking construction of large-span steel box girders (corresponding parameters...). / =0.4, / =0.2), this standard formula not only failed to maintain its conservatism, but also overestimated the actual load-bearing capacity of the web. Meanwhile, as Figure 5 As shown, with As the number of variables increases, the error in the calculation method in EN 1993-1-5 also gradually increases. This is because... With the increase of the buckling coefficient, the effect of the tension field between the web and the transverse stiffeners becomes more significant. Therefore, the calculation formula in EN 1993-1-5 cannot be directly used to determine the ultimate bearing capacity of the box girder web. Therefore, the correction method proposed in this invention corrects the buckling reduction coefficient. This corrects errors in the standard formula, and the corrected formula does not require post-buckling reserve. Instead of using numerical analysis such as modeling to assist in the calculation, the ultimate bearing capacity of the steel beam web can be obtained more accurately by directly calculating with simple theoretical formulas.

[0022] This method includes the following steps: S1: Calculate the buckling reduction coefficient Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The ratio of key parameters; the buckling reduction coefficient Used to correct the calculation formula for the local compressive bearing capacity of the web of steel beams; Perform buckling reduction coefficient Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The steps for calculating the ratio of each key parameter are as follows: The ratios of several geometric parameters related to the local compressive bearing capacity of the steel beam web are selected as analysis variables. These geometric parameters include loading length, flange thickness, flange yield strength, flange width, web height, regularized slenderness ratio, and critical buckling load. This can be observed through the formulas. Compared with regularized slenderness ratio Related, and And with / , / , / , , Based on the relevant parameters, these types of parameters have been preliminarily identified as key influencing parameters; the relevant formulas are shown below: ; ; ; ; ; .in The elastic buckling coefficient; It is the elastic modulus.

[0023] Using the ratio of geometric parameters as the independent variable, the buckling reduction coefficient Plot the relationship curve for the dependent variable; By observing the influence of changes in the ratios of various geometric parameters on the slope of the relationship curve, the effect of different ratios of geometric parameters on the buckling reduction coefficient is quantitatively assessed. Sensitivity to identify the buckling reduction coefficient Significant impact The ratios of several key parameters. Here, after calculation and plotting, two of the most sensitive ( / , / The key parameters are used as input variables; S2: Based on engineering experience and surveys of actual bridge parameters, determine The range of the key parameter ratios is defined; and values ​​are gradually taken at equal steps within the engineering adaptation range to generate a variable sequence of corresponding key parameter ratios. In this embodiment, the ratio of the key parameters selected in step S1 is ( / , / Based on practical engineering experience, / The value range is set between 0.1 and 0.8, with a step interval of 0.1. ， A total of 8 sets of variables are generated, and the number of variables is counted as follows: , / Defined between 0.5 and 1.0, with a step size interval of 0.1, a total of 6 sets of variables are generated, and the number of variables is counted as follows. .

[0024] S3: Establish A finite element model of a steel box girder, wherein the number of finite element models is... for The product of the number of variables in the variable sequence of the ratio of key parameters. , Indicates the first The number of variables used for the ratio of the key parameters (in this embodiment, ) (A total of 48 models); In the finite element simulation, one of the key parameter ratios is set as a constant, and the other is treated as a variable. The range of the variable is inferred by comparing the constant value with the range of the key parameter ratio. Simultaneously, other key parameter ratios and ratios of other geometric parameters related to the buckling reduction coefficient are set as constants. This ensures that the only difference between the models comes from the change in the key parameter ratios, providing a highly comparable analytical basis for subsequent extraction of ultimate bearing capacity and flange vertical stress. Here, the web height is determined to be a constant. =1000mm, then the values ​​for different ranges can be calculated based on the proportion. and The size; use the above parameters as input to the finite element model; S4: Obtained through finite element analysis Numerical solutions of the ultimate bearing capacity for each finite element model And extract the longitudinal stress level of the flange. The longitudinal stress level of the flange is extracted here for the calculation of post-buckling reserve, thus taking into account the effective loading length. Greater than What happened next.

[0025] It should be noted that the method for extracting the ultimate bearing capacity of the finite element model of the steel box girder web is common knowledge in the field of bridge engineering and should be known by those skilled in the art. Only a brief description of the process is provided here. A segmental model of the steel box girder is established using Abaqus finite element software. During model creation, shell element properties are selected for component creation, and the elastic, plastic, and section properties of the steel are defined. After assembling the components, corresponding material properties are assigned, and boundary conditions are arranged. Simply supported boundary supports are set at the supports of the steel box girder, and lateral supports are set on the supports to restrict its translation in the Z direction. The load application point and loading area are coupled through coupling constraints, representing the simulated loading block form. The load is applied at the application point using the arc-length method, and the maximum deflection of the upper flange is controlled. The model is calculated, and the load-displacement curve at the application point is extracted. The numerical solution of the ultimate bearing capacity can be determined based on the curve. F FEM Size, for example, in the figure F FEM The value is 812 kN.

[0026] Specifically, when creating a 3D model of a steel box girder segment in Abaqus, shell elements (S4R four-node reduced integral elements are recommended) are used to describe the web and flanges, and section properties are defined according to the actual cross-section. Then, the elastic-plastic constitutive properties (elastic modulus, yield strength, and stress-strain relationship) of the steel are assigned to each component, and assembly is completed. Boundary conditions are set according to the engineering supports, such as... Figure 3 As shown, simply supported constraints are applied at the supports (Ux=Uy=0 on one side and Uy=0 on the other side), and lateral supports (Uz=0) are arranged at the locations where lateral translation needs to be restricted to accurately reflect the constraint conditions. RP1 is a reference point defined in the finite element analysis, located at the center of the upper flange. Through coupling constraints, RP1 is bound to the loading length region to simulate the loading of the loading block. F is applied by displacement and is defined as -0.5. To simulate the force transmission of the pad / loading block, the nodes on the loading area are connected to a single point of action through coupling constraints, so that the coupling point represents the force transmission of the entire loading block. Then, the vertical load is applied at the coupling point using the arc length method (Riks) to fully capture the buckling instability and softening process. To ensure the reliability of the results, the mesh should be refined and convergence checked in key areas, and initial geometric imperfections or material nonlinearities should be introduced when necessary to improve the engineering representativeness. After the calculation is completed, the load-displacement curve is extracted at the coupling point. The peak value of the curve or the load corresponding to the significant softening is the ultimate bearing capacity obtained by finite element method. (Example image) =812kN).

[0027] longitudinal stress level of flange Including the longitudinal stress level of the inner hinge flange and longitudinal stress of the outer hinge flange It should be noted that when extracting the longitudinal stress level of the inner hinge flange... As mentioned earlier, the load-displacement curve of the steel box girder web has been obtained. The calculation and analysis step corresponding to the peak bearing capacity can be determined from the curve. Under this analysis step, the stress in the X-axis direction of the structure is viewed, and the average stress along the Z-direction path of the upper flange 1 cm away from the edge of the loading block is taken as the longitudinal stress level of the flange. .

[0028] Specifically, at the longitudinal stress level of the inner hinge flange During the extraction process, the analysis step corresponding to the ultimate bearing capacity (i.e., the peak of the curve or the condition of significant softening) is first determined based on the obtained load-displacement curve. The stress field is then read from the result file of this analysis step along the X direction (longitudinal) of the structural coordinate system. Subsequently, a sampling line is established on the upper flange along a path parallel to the Z direction, 1 cm from the edge of the loading block. The longitudinal stress components of all nodes or integration points are extracted along this path. Finally, the arithmetic mean of the stress values ​​along this path is calculated, and the resulting mean is used as the longitudinal stress level of the flange. This is used for subsequent correction calculations and parameter calibration. Longitudinal stress of the outer hinge flange. The extraction method is the same as that for the inner hinge, but the sampling path is different. For the longitudinal stress level of the outer hinge flange... Stress data were collected along a path parallel to the upper flange and 1 cm away from the position of the upper flange support stiffener, and then the average stress along the path was calculated.

[0029] S5: Based on the results of finite element analysis, The local compressive bearing capacity of the web of the steel beam corresponding to each finite element model is corrected; Based on the results of finite element calculations, The formula for correcting the local compressive bearing capacity of the steel beam web corresponding to the finite element model is as follows: In the formula, This refers to the corrected local compressive bearing capacity of the steel beam web. Reserve for post-buckling; For the corrected flange stress ratio, , They are external hinges and internal hinge The corrected flange stress ratio at the location, compared with the longitudinal stress of the outer hinge flange. and the longitudinal stress level of the inner hinge flange correspond; All of the following parameters are constant values. This refers to the length of the transverse stiffening rib; The effective load length; Web thickness; The width of the flange; For flange thickness; The flange yield strength; The web height; The loading length.

[0030] Here Less than hour， think The results calculated by the finite element method correspond to the specifications. Corrected exact solution ， And when big At Then the finite element calculation results need to be obtained Subtract the corresponding post-buckling reserve from the base. Because of the European standard Unable to consider The influence of this factor needs to be excluded.

[0031] S6: Calculate the corrected buckling reduction factor based on the corrected local compressive bearing capacity of the steel beam web. ; The corrected buckling reduction factor is calculated based on the corrected local compressive bearing capacity of the steel beam web. The formula is as follows: In the formula, For yield load, This is a partial factor, with an empirical value of 1.0. Here, the corrected bearing capacity is used. Divide by / That is to say, it is believed / The accurate value does not need to be corrected, thus eliminating the interference of the term parameter on the correction result of the buckling reduction coefficient.

[0032] S7: Calculate the regularized slenderness ratio for each finite element model and fit the corrected buckling reduction coefficient related to the regularized slenderness ratio. The expression; Corrected buckling reduction coefficient related to regularized slenderness ratio The expression is: In the formula, To regularize the slenderness ratio.

[0033] S8: The corrected buckling reduction coefficient Replace the buckling reduction factor in the formula for calculating the local compressive bearing capacity of the web of a steel beam with the expression. This is to correct the calculation formula for the local compressive bearing capacity of the web of steel beams.

[0034] Comparative analysis shows that the methods in the background technology all have significant deviations in calculating the ultimate bearing capacity of the web of steel beams under local loads: within a specific parameter range ( / =0.4 and / When the value is less than 0.2, unsafe prediction results occur, and the predictions of European standards are generally conservative. The formula proposed in this patent, however, has better applicability and is more secure and accurate.

[0035] Figure 6 Showing and The comparison relationship. By modifying the calculation formula of the buckling reduction coefficient, the modified buckling reduction coefficient is adopted. The formula replaces the tortuosity reduction factor in the original EN 1993-1-5 standard, while retaining other calculation formulas in the standard. The revised prediction results show that... / The mean value decreased to 1.65, and the standard deviation decreased to 0.239.

[0036] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for correcting the calculation formula of the local compressive bearing capacity of the web of a steel beam, characterized in that, Includes the following steps: Perform buckling reduction coefficient Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The ratio of key parameters; the buckling reduction coefficient Used to correct the calculation formula for the local compressive bearing capacity of the web of steel beams; Based on engineering experience and surveys of actual bridge parameters, determine The range of the key parameter ratios is defined; and values ​​are gradually taken at equal steps within the engineering adaptation range to generate a variable sequence of corresponding key parameter ratios. Establish A finite element model of a steel box girder, wherein the number of finite element models is... for The product of the number of variables in the variable sequence of key parameter ratios; in the finite element simulation, one parameter of one of the key parameter ratios is set as a constant value, and the other parameter is used as a variable. The range of values ​​of the variable is inferred by the constant value and the range of the key parameter ratio. At the same time, other key parameter ratios and other geometric parameter ratios related to the buckling reduction coefficient are set as constant values. The above parameters are used as inputs to the finite element model. Obtained through finite element analysis Numerical solutions of the ultimate bearing capacity for each finite element model And extract the longitudinal stress level of the flange. ; Based on the results of finite element calculations, The local compressive bearing capacity of the web of the steel beam corresponding to each finite element model is corrected; The corrected buckling reduction factor is calculated based on the corrected local compressive bearing capacity of the steel beam web. ; Calculate the regularized slenderness ratio for each finite element model, and fit the corrected buckling reduction coefficient related to the regularized slenderness ratio. The expression; Based on the modified buckling reduction coefficient Replace the buckling reduction factor in the formula for calculating the local compressive bearing capacity of the web of a steel beam with the expression. This is to correct the calculation formula for the local compressive bearing capacity of the web of steel beams.

2. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 1, characterized in that: Perform buckling reduction coefficient Sensitivity parameter analysis was performed to obtain the effect on buckling reduction coefficient. Significant impact The steps for calculating the ratio of each key parameter are as follows: The ratios of several geometric parameters related to the local compressive bearing capacity of the steel beam web were selected as analytical variables. Using the ratio of geometric parameters as the independent variable, the buckling reduction coefficient Plot the relationship curve for the dependent variable; By observing the influence of changes in the ratios of various geometric parameters on the slope of the relationship curve, the effect of different ratios of geometric parameters on the buckling reduction coefficient is quantitatively assessed. Sensitivity to identify the buckling reduction coefficient Significant impact The ratio of key parameters.

3. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 2, characterized in that: The geometric parameters include loading length, flange thickness, flange yield strength, flange width, web height, regularized slenderness ratio, and critical buckling load.

4. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 3, characterized in that: Based on the results of finite element calculations, The formula for correcting the local compressive bearing capacity of the steel beam web corresponding to the finite element model is as follows: In the formula, The corrected local compressive bearing capacity of the steel beam web; Reserve for post-buckling; For the corrected flange stress ratio, , They are external hinges and internal hinge The corrected flange stress ratio at the location; All of the following parameters are constant values. This refers to the length of the transverse stiffening rib; The effective load length; Web thickness; The width of the flange; For flange thickness; The flange yield strength; This refers to the height of the web. The length to be loaded.

5. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 4, characterized in that: The corrected buckling reduction factor is calculated based on the corrected local compressive bearing capacity of the steel beam web. The formula is as follows: In the formula, For yield load, This is the partial factor, with an empirical value of 1.

0.

6. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 5, characterized in that: Corrected buckling reduction coefficient related to regularized slenderness ratio The expression is: In the formula, To regularize the slenderness ratio.

7. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 1, characterized in that: The method for extracting the ultimate bearing capacity of a finite element model is as follows: In the finite element model, the point of application of the load is coupled with the loading area for constraint. Vertical loads are applied at the point of application using the arc-length method, and the maximum deflection of the upper flange is controlled. The finite element model is calculated, and the load-displacement curves at the points of application are extracted. The peak value of the load-displacement curve or the load corresponding to the occurrence of significant softening is the numerical solution of the ultimate bearing capacity obtained by the finite element method. .

8. The method for correcting the calculation formula for the local compressive bearing capacity of the web of a steel beam according to claim 7, characterized in that: Extracting longitudinal stress level of the flange The steps include: Determine the analysis step corresponding to the ultimate bearing capacity based on the obtained load-displacement curve; The stress field is read in the X direction of the structural coordinate system in the result file of this analysis step; The arithmetic mean of the stress along the Z-direction path of the upper flange at a distance of 1 cm from the edge of the loading block in the stress field is taken as the longitudinal stress level of the flange. .

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