Method for calculating bearing capacity of power transmission tower angle steel after nondestructive reinforcement

Abstract

The invention relates to the field of power transmission equipment, in particular to a method for calculating the bearing capacity of power transmission tower angle steel after nondestructive reinforcement, which comprises the following steps: selecting a plurality of equilateral angle steel within a preset slenderness ratio parameter range, acquiring the initial bending amplitude of an equilateral angle steel sample, determining the actual bearing capacity, and determining a defect influence coefficient; friction contact pairs are arranged between the reinforcing members and the angle steel, between the angle steel and the reinforcing plates and between the reinforcing plates and the reinforcing members, a friction coefficient reference value is determined, and the corresponding peak load of each equilateral angle steel in the reinforcing form parameter range is obtained through a finite element model; according to the method, a curve of the slenderness ratio and the peak load of the equilateral angle steel and a curve of the reinforcing form and the peak load of the equilateral angle steel are constructed, the slenderness ratio and the reinforcing form of the equilateral angle steel are selected, and a bearing capacity calculation formula is selected according to the slenderness ratio of the equilateral angle steel to calculate the bearing capacity. And the calculation deviation caused by empirical evaluation of the friction coefficient significantly improves the accuracy of bearing capacity calculation.

Description

Technical Field

[0001] This invention relates to the field of power transmission equipment, and in particular to a method for calculating the bearing capacity of transmission tower angle steel after non-destructive reinforcement. Background Technology

[0002] Transmission towers, as key supporting structures for power transmission, play a vital role in the power system. They not only support high-voltage transmission lines but also ensure the safe and stable transmission of electricity from power plants to users. With the rapid development of my country's economy and the acceleration of industrialization, electricity demand continues to grow, placing higher demands on the performance and reliability of transmission towers.

[0003] The stability and reliability of transmission towers directly affect the normal operation of the power grid and are crucial for ensuring power supply and economic development. However, over time, transmission towers may experience a decline in load-bearing capacity and even collapse due to natural disasters (such as typhoons and earthquakes), long-term environmental erosion, inadequate design standards, or human-caused damage. Reinforcing transmission towers not only improves their disaster resistance but also extends their service life, reducing the high costs associated with collapse or tower replacement. Through innovation and application of reinforcement technologies, strong guarantees can be provided for the safe and reliable operation of the power system.

[0004] Chinese Patent Publication No. CN119167701A discloses a method for calculating the bearing capacity of angle steel in transmission towers after non-destructive reinforcement. It includes calculating the ultimate bearing capacity (Bcultimate) and repair wind load (Wlrepair) corresponding to different repair finite element models; and selecting an appropriate repair and reinforcement method based on the numerical states of the ultimate bearing capacity (Bcultimate) and repair wind load (Wlrepair). This invention obtains corresponding reference values ​​by simulating repair finite element models under different repair and reinforcement methods, compares them with corresponding conventional reference data, calculates the final matching rate, and matches the optimal repair and reinforcement method for different defects, thereby improving the simulation effect.

[0005] However, the following problems still exist in the existing technology.

[0006] In the existing technology, the initial defects and friction coefficient are not accurately estimated, which leads to deviations in the calculation of bearing capacity. Furthermore, the slenderness ratio and clamp spacing parameters are not selected based on their influence on the peak load, resulting in over-design or under-fitting problems. Summary of the Invention

[0007] To address this, the present invention provides a method for calculating the bearing capacity of transmission tower angle steel after non-destructive reinforcement, which overcomes the problems of inaccurate estimation of initial defects and friction coefficient, leading to deviations in the calculation of bearing capacity, and the problems of over-design or insufficient adaptation caused by not selecting slenderness ratio and clamp spacing parameters according to the influence of slenderness ratio and clamp spacing on peak load.

[0008] To achieve the above objectives, this invention provides a method for calculating the bearing capacity of transmission tower angle steel after non-destructive reinforcement, comprising:

[0009] Select several equal-sided angle steels within the preset slenderness ratio parameter range;

[0010] The initial bending amplitude of the equilateral angle steel sample is obtained through geometric detection.

[0011] Determine the actual bearing capacity corresponding to the initial bending amplitude of the equilateral angle steel sample, and determine the defect influence coefficient based on the ratio of the actual bearing capacity to the ideal bearing capacity;

[0012] Friction contact pairs are set between the reinforcement member and the angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement member. The slippage is obtained through pre-simulation. The slippage is compared with the actual monitored slippage to determine the reference value of the friction coefficient.

[0013] The peak load of each equal angle steel within the range of reinforcement form parameters was obtained by using a finite element model.

[0014] Construct curves of slenderness ratio versus peak load for equilateral angle steel, and construct curves of reinforcement methods versus peak load for equilateral angle steel;

[0015] The slenderness ratio and reinforcement method of the equal angle steel are selected based on the curves of the slenderness ratio and peak load of the equal angle steel and the curves of the reinforcement method and peak load of the equal angle steel.

[0016] The bearing capacity is calculated based on the slenderness ratio of equilateral angle steel using the bearing capacity calculation formula, including: introducing a defect influence coefficient into the flexural buckling bearing capacity formula to calculate the flexural buckling bearing capacity, or introducing a defect influence coefficient and a friction coefficient benchmark value into the flexural-torsional buckling bearing capacity formula to calculate the flexural-torsional buckling bearing capacity.

[0017] The bearing capacity is compared with the peak load obtained from the finite element model to determine whether the coefficients of the bearing capacity calculation formula need to be adjusted.

[0018] Furthermore, the preset slenderness ratio parameter ranges from 50 to 130.

[0019] Furthermore, the process of determining the actual bearing capacity corresponding to the initial bending amplitude of the equilateral angle steel sample includes,

[0020] Obtain several initial bending amplitudes of the equilateral angle steel sample;

[0021] Calculate the average of several initial bending amplitudes of the equilateral angle steel sample;

[0022] A three-dimensional geometric model is constructed using finite element software. Defect values ​​are assigned based on the average of several initial bending amplitudes of the equilateral angle steel sample, and the peak load is obtained as the actual bearing capacity.

[0023] Furthermore, the process of setting friction contact pairs between the reinforcing member and the angle steel, the angle steel and the reinforcing plate, and the reinforcing plate and the reinforcing member, and obtaining the slippage amount through pre-simulation, includes:

[0024] Construct a combined model of angle steel, reinforcing plate, and reinforcing components in finite element software;

[0025] Several friction coefficients are sequentially set between the reinforcement member and the angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement member;

[0026] Several slippage monitoring points are set at the edges of the reinforcement components and angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement components.

[0027] Obtain the slippage at each monitoring point corresponding to each friction coefficient.

[0028] Furthermore, the process of comparing the slip amount with the actual monitored slip amount to determine the reference value of the friction coefficient includes,

[0029] Obtain the actual monitored slip volume;

[0030] Select the slip amount of the monitoring point corresponding to the friction coefficient with the smallest difference from the actual monitored slip amount;

[0031] The friction coefficient is determined as the reference value for the friction coefficient.

[0032] Furthermore, the range of reinforcement parameters includes clamp spacing of 300mm, 500mm, and 700mm.

[0033] Furthermore, the process of selecting the slenderness ratio and reinforcement method of the equilateral angle steel based on the curves of the slenderness ratio and peak load, and the curves of the reinforcement method and peak load, includes the following:

[0034] The curves of slenderness ratio and peak load of equal-angle steel and the curves of reinforcement form of equal-angle steel and peak load are respectively fitted with straight lines to obtain the slope of the straight lines;

[0035] The slope of the fitted straight line corresponding to the curve of slenderness ratio of equilateral angle steel versus peak load is compared with the preset straight line slope range.

[0036] If the slope of the fitted straight line corresponding to the curve of slenderness ratio of equal angle steel and peak load belongs to the preset straight line slope range, then the maximum value within the preset slenderness ratio parameter range is selected.

[0037] If the slope of the fitted straight line corresponding to the curve of slenderness ratio of equal angle steel and peak load does not belong to the preset straight line slope range, then the middle value within the preset slenderness ratio parameter range shall be selected.

[0038] The slope of the fitted straight line corresponding to the curve of the equilateral angle steel reinforcement form and the peak load is compared with the preset straight line slope range.

[0039] If the slope of the fitted straight line corresponding to the curve of the equal angle steel reinforcement form and the peak load belongs to the preset straight line slope range, then the maximum value within the range of reinforcement form parameters is selected.

[0040] If the slope of the fitted straight line corresponding to the curve of the equal angle steel reinforcement form and the peak load does not fall within the preset straight line slope range, then the middle value within the range of reinforcement form parameters shall be selected.

[0041] Furthermore, the process of calculating the bearing capacity based on the slenderness ratio of the equilateral angle steel using the bearing capacity calculation formula includes,

[0042] The slenderness ratio of the equilateral angle steel is compared with a preset slenderness ratio comparison threshold.

[0043] If the slenderness ratio of the equilateral angle steel is less than the preset slenderness ratio comparison threshold, then the flexural buckling capacity is calculated by introducing a defect influence coefficient into the flexural buckling capacity formula.

[0044] If the slenderness ratio of the equilateral angle steel is greater than or equal to the preset slenderness ratio comparison threshold, then the defect influence coefficient and friction coefficient are introduced into the formula for flexural-torsional buckling bearing capacity to calculate the flexural-torsional buckling bearing capacity.

[0045] Furthermore, the process of comparing the bearing capacity with the peak load obtained from the finite element model to determine whether to adjust the formula coefficients includes,

[0046] Obtain the absolute value of the difference between the bearing capacity and the peak load;

[0047] Calculate the ratio of the absolute value to the peak load;

[0048] If the ratio is greater than a preset ratio comparison threshold, it is determined that the formula coefficients should be adjusted.

[0049] Furthermore, the flexural buckling bearing capacity formula is calculated by introducing a defect influence coefficient, wherein the flexural buckling bearing capacity is equal to the product of the defect influence coefficient and the flexural buckling bearing capacity formula;

[0050] The formula for calculating flexural-torsional buckling bearing capacity introduces the defect influence coefficient and the reference value of the friction coefficient. The flexural-torsional buckling bearing capacity is equal to the product of the defect influence coefficient, the reference value of the friction coefficient, and the formula for flexural-torsional buckling bearing capacity.

[0051] Compared with existing technologies, this invention selects several equilateral angle steels within a preset slenderness ratio parameter range, obtains the initial bending amplitude of the equilateral angle steel samples, determines the actual bearing capacity, determines the defect influence coefficient, sets friction contact pairs between the reinforcement member and the angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement member, determines the reference value of the friction coefficient, obtains the peak load corresponding to each equilateral angle steel within the reinforcement form parameter range through a finite element model, constructs the curve of equilateral angle steel slenderness ratio versus peak load and the curve of equilateral angle steel reinforcement form versus peak load, selects the slenderness ratio and reinforcement form of the equilateral angle steel, and calculates the bearing capacity based on the bearing capacity calculation formula selected according to the slenderness ratio of the equilateral angle steel. This invention avoids calculation deviations caused by coarsely handling defects and empirically selecting the friction coefficient, significantly improving the accuracy of bearing capacity calculation.

[0052] In particular, this invention determines the actual bearing capacity corresponding to the initial bending amplitude of the equilateral angle steel sample, and determines the defect influence coefficient based on the ratio of the actual bearing capacity to the ideal bearing capacity. Since initial defects inevitably exist during the manufacturing, transportation, and installation of steel in reality, the initial bending amplitude of the equilateral angle steel sample is obtained through geometric detection, and the average value of the initial bending amplitude of multiple samples is further calculated. Then, based on the finite element model, the defect value is assigned to this average value to accurately obtain the actual bearing capacity under the corresponding initial defect state. At the same time, the defect influence coefficient is determined by the ratio of the actual bearing capacity to the ideal bearing capacity without defects, transforming the inevitable initial defects of the steel into quantifiable coefficients. This allows the calculation of bending buckling and bending-torsional buckling bearing capacity to specifically correct the bearing capacity reduction caused by defects, avoiding calculation deviations caused by ignoring or coarsely handling defects, significantly improving the accuracy of bearing capacity calculation, and providing a more reliable theoretical basis for the structural safety of transmission towers after reinforcement.

[0053] In particular, this invention obtains the slip amount through pre-simulation and compares it with the actual monitored slip amount to determine the benchmark value of the friction coefficient. In actual situations, the frictional force transmission at the contact surfaces of the reinforcement member and the angle steel, and the angle steel and the reinforcement plate, is a key factor affecting the flexural-torsional buckling bearing capacity. Traditional methods often directly use empirical friction coefficients without considering the differences in the contact surface conditions in actual engineering, which can easily lead to errors in flexural-torsional buckling calculations. By calibrating and comparing based on actual data, the friction coefficient suitable for the reinforcement scenario can be accurately determined, avoiding the subjectivity of empirical values. This makes the correction of the friction effect in the flexural-torsional buckling bearing capacity calculation more realistic and effectively ensures the accuracy of the flexural-torsional buckling calculation results.

[0054] In particular, this invention selects the slenderness ratio and reinforcement method of equilateral angle steel based on the curves of slenderness ratio and peak load, as well as the curves of reinforcement method and peak load. Traditional methods often rely on engineer experience or take values ​​based on the worst-case scenario when selecting the slenderness ratio and reinforcement method, which can easily lead to over-design or insufficient adaptation. This invention obtains the peak load corresponding to different slenderness ratios and reinforcement methods through a finite element model, constructing curves of slenderness ratio versus peak load and curves of reinforcement method versus peak load. Then, the curves are fitted with straight lines, and the slope of the fitted line is used to determine the degree of influence of the parameters on the peak load. If the slope is large, it indicates that changes in the slenderness ratio or the clamp spacing have a significant impact on the peak load. In this case, the slenderness ratio and clamp spacing corresponding to the maximum peak load are selected to maximize the reinforcement effect. If the slope is gentle, it indicates that changes in the parameters have a weak impact on the peak load. In this case, intermediate parameter values ​​are selected to balance the reinforcement effect and cost. This avoids the limitations of empirical values ​​and achieves optimal adaptation of slenderness ratio and reinforcement method, taking into account both reinforcement reliability and engineering economy. Attached Figure Description

[0055] Figure 1 This is a step diagram illustrating the method for calculating the bearing capacity of transmission tower angle steel after non-destructive reinforcement according to an embodiment of the invention.

[0056] Figure 2 A logic diagram for calculating the bearing capacity using the formula for selecting the slenderness ratio of the equilateral angle steel in an embodiment of the invention;

[0057] Figure 3 This is a logic diagram for determining whether to adjust the coefficients in the bearing capacity calculation formula, as shown in the embodiment of the invention. Detailed Implementation

[0058] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0059] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0060] Please see Figure 1-3 As shown, the present invention provides a method for calculating the bearing capacity of transmission tower angle steel after non-destructive reinforcement, comprising:

[0061] Step S1: Select several equal-sided angle steels within the preset slenderness ratio parameter range;

[0062] Step S2: Obtain the initial bending amplitude of the equilateral angle steel sample through geometric detection;

[0063] Step S3: Determine the actual bearing capacity corresponding to the initial bending amplitude of the equilateral angle steel sample, and determine the defect influence coefficient based on the ratio of the actual bearing capacity to the ideal bearing capacity.

[0064] Step S4: Set friction contact pairs between the reinforcement member and the angle steel, the angle steel and the reinforcing plate, and the reinforcing plate and the reinforcement member; obtain the slippage amount through pre-simulation; compare the slippage amount with the actual monitored slippage amount; and determine the reference value of the friction coefficient.

[0065] Step S5: Obtain the peak load corresponding to each equal angle steel within the range of reinforcement form parameters using the finite element model;

[0066] Step S6: Construct the curve of slenderness ratio of equal angle steel versus peak load and construct the curve of reinforcement form of equal angle steel versus peak load;

[0067] Step S7: Select the slenderness ratio and reinforcement method of the equal angle steel based on the curves of the slenderness ratio and peak load of the equal angle steel and the curves of the reinforcement method and peak load of the equal angle steel.

[0068] Step S8: Calculate the bearing capacity based on the slenderness ratio of the equilateral angle steel using the bearing capacity calculation formula. This includes: introducing a defect influence coefficient into the flexural buckling bearing capacity formula to calculate the flexural buckling bearing capacity; or introducing a defect influence coefficient and a friction coefficient benchmark value into the flexural-torsional buckling bearing capacity formula to calculate the flexural-torsional buckling bearing capacity.

[0069] Step S9: Compare the bearing capacity with the peak load obtained from the finite element model to determine whether to adjust the coefficients of the bearing capacity calculation formula.

[0070] In this embodiment, Q345 steel is selected as the material, including nine specifications: L80×7, L100×8, L125×8, L125×10, L125×12, L140×10, L160×12, L180×14 and L200×18.

[0071] It is understandable that when selecting equilateral angle steel samples, equilateral angle steel of various specifications should be separated, and a certain number of equilateral angle steel of each specification should be selected as samples. In this embodiment, 10 samples are selected for each specification.

[0072] In this embodiment, a laser rangefinder is used to detect the initial bending amplitude of the equilateral angle steel sample along the sample length direction.

[0073] In this embodiment, the peak load corresponding to each equilateral angle steel within the range of reinforcement form parameters is obtained through a finite element model. Firstly, the finite element model is constructed through the following five aspects:

[0074] (1) Material parameters

[0075] The constitutive model of Q345 steel adopts the bilinear isotropic hardening model (BISO), neglecting the increase in material strength after yielding, and obeys the VON-MISES yield criterion. The elastic modulus is 2.06×10⁵ N / mm², and the Poisson's ratio is 0.3.

[0076] (2) Unit Type

[0077] The solid element used is Solid185, defined by 8 nodes, each with 3 degrees of freedom for translation along the x, y, and z directions. The element exhibits hyperelasticity, stress stiffening, creep, large deformation, and large strain capabilities. A hybrid mode can also be used to simulate nearly incompressible elasto-plastic materials and fully incompressible hyperelastic materials.

[0078] The contact elements used are contact170, 173 3D, 4-node low-order quadrilateral elements to simulate the contact and sliding between the 3D target surface and the deformable (flexible) surface of the contact element. Based on the principle of setting the contact and target surfaces, one side of the angle steel and reinforcing plate is set as the target surface, and the other side of the reinforcing member is set as the contact surface.

[0079] (3) Contact surface setting

[0080] Considering the actual conditions of the components, contact pairs are set between the reinforcement members and angle steel, the angle steel and the reinforcing plate, and the reinforcing plate and the reinforcement members to simulate possible relative slippage between the reinforcement members, the reinforcing plate, and the angle steel. The contact type is frictional contact.

[0081] (4) Consider initial defects

[0082] Initial defects are unavoidable during the processing and transportation of steel structure components. In this embodiment, initial bending is considered.

[0083] (5) Boundary conditions

[0084] In current tower design calculations, it is generally assumed that the ends of the members are hinged, and only axial tension and compression are considered. Therefore, in the finite element model, the degrees of freedom of the end nodes are coupled by MPC184 elements, constraining the displacements of the upper coupling points in the UX, UY, and ROTZ directions, and constraining the displacements of the lower coupling points in the UX, UY, UZ, and ROTZ directions.

[0085] In this embodiment, a curve is constructed showing the slenderness ratio of the equilateral angle steel versus the peak load, with the slenderness ratio as the horizontal axis and the peak load as the vertical axis. The equilateral angle steels differ only in their slenderness ratio.

[0086] In this embodiment, a curve is constructed showing the relationship between the reinforcement type of the equilateral angle steel and the peak load, with the reinforcement type of the equilateral angle steel as the horizontal axis and the peak load as the vertical axis. The only difference between the equilateral angle steels is the reinforcement type.

[0087] In this embodiment, the flexural buckling bearing capacity formula based on GB50017-2003 is as follows:

[0088]

[0089] Where N is the bearing capacity, f is the design value of the axial compressive strength of the steel, and A is the cross-sectional area. This is the overall stability coefficient of the component. The value is determined by referring to the table according to the standard.

[0090] In this embodiment, the formula for flexural-torsional buckling capacity based on GB50017-2003 is as follows:

[0091]

[0092] Where N is the bearing capacity, f is the design value of the axial compressive strength of the steel, and A is the cross-sectional area. This is the stability coefficient based on bending-torsion conversion. The value is determined by referring to the table according to the standard.

[0093] Specifically, the preset slenderness ratio parameter ranges from 50 to 130.

[0094] Specifically, the process of determining the actual bearing capacity corresponding to the initial bending amplitude of the equilateral angle steel sample includes,

[0095] Obtain several initial bending amplitudes of the equilateral angle steel sample;

[0096] Calculate the average of several initial bending amplitudes of the equilateral angle steel sample;

[0097] A three-dimensional geometric model is constructed using finite element software. Defect values ​​are assigned based on the average of several initial bending amplitudes of the equilateral angle steel sample, and the peak load is obtained as the actual bearing capacity.

[0098] Specifically, this invention determines the actual bearing capacity corresponding to the initial bending amplitude of an equilateral angle steel sample, and determines the defect influence coefficient based on the ratio of the actual bearing capacity to the ideal bearing capacity. Since initial defects inevitably exist during the manufacturing, transportation, and installation of steel, the initial bending amplitude of the equilateral angle steel sample is obtained through geometric detection. The average initial bending amplitude of multiple samples is then calculated, and a defect value is assigned to this average value based on a finite element model, accurately obtaining the actual bearing capacity under the corresponding initial defect state. Simultaneously, the defect influence coefficient is determined by the ratio of the actual bearing capacity to the ideal bearing capacity without defects, transforming the inevitable initial defects of the steel into quantifiable coefficients. This allows the calculation of bending buckling and flexural-torsional buckling bearing capacities to specifically correct the bearing capacity reduction caused by defects, avoiding calculation deviations caused by ignoring or roughly handling defects. This significantly improves the accuracy of bearing capacity calculations and provides a more reliable theoretical basis for the structural safety of reinforced transmission towers.

[0099] Specifically, the process of setting friction contact pairs between the reinforcement member and the angle steel, the angle steel and the reinforcing plate, and the reinforcing plate and the reinforcement member, and obtaining the slippage amount through pre-simulation includes,

[0100] Construct a combined model of angle steel, reinforcing plate, and reinforcing components in finite element software;

[0101] Several friction coefficients are sequentially set between the reinforcement member and the angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement member;

[0102] Several slippage monitoring points are set at the edges of the reinforcement components and angle steel, the angle steel and the reinforcement plate, and the reinforcement plate and the reinforcement components.

[0103] Obtain the slippage at each monitoring point corresponding to each friction coefficient.

[0104] In this embodiment, several friction coefficients are sequentially set between the reinforcing member and the angle steel, the angle steel and the reinforcing plate, and the reinforcing plate and the reinforcing member, wherein the friction coefficients are sequentially set to 0.1, 0.2, and 0.3.

[0105] It is understandable that the slip amount is obtained when the friction coefficient is 0.1, 0.2, and 0.3 respectively.

[0106] Specifically, the process of comparing the slip amount with the actual monitored slip amount to determine the reference value of the friction coefficient includes,

[0107] Obtain the actual monitored slip volume;

[0108] Select the slip amount of the monitoring point corresponding to the friction coefficient with the smallest difference from the actual monitored slip amount;

[0109] The friction coefficient is determined as the reference value for the friction coefficient.

[0110] Specifically, this invention obtains the slip amount through pre-simulation, compares the slip amount with the actual monitored slip amount, and determines the benchmark value of the friction coefficient. In actual situations, the frictional force transmission at the contact surfaces of the reinforcement member and the angle steel, and the angle steel and the reinforcement plate, is a key factor affecting the flexural-torsional buckling bearing capacity. Traditional methods often directly use empirical friction coefficients without considering the differences in the contact surface conditions in actual engineering, which can easily lead to errors in flexural-torsional buckling calculations. By calibrating and comparing based on actual data, the friction coefficient suitable for the reinforcement scenario can be accurately determined, avoiding the subjectivity of empirical values. This makes the correction of the friction effect in the flexural-torsional buckling bearing capacity calculation more realistic and effectively ensures the accuracy of the flexural-torsional buckling calculation results.

[0111] Specifically, the range of reinforcement parameters includes clamp spacing of 300mm, 500mm, and 700mm.

[0112] Specifically, the process of selecting the slenderness ratio and reinforcement method of the equal-angle steel based on the curves of the slenderness ratio and peak load of the equal-angle steel and the curves of the reinforcement method and peak load of the equal-angle steel includes the following steps:

[0113] The curves of slenderness ratio and peak load of equal-angle steel and the curves of reinforcement form of equal-angle steel and peak load are respectively fitted with straight lines to obtain the slope of the straight lines;

[0114] The slope of the fitted straight line corresponding to the curve of slenderness ratio of equilateral angle steel versus peak load is compared with the preset straight line slope range.

[0115] If the slope of the fitted straight line corresponding to the curve of slenderness ratio of equal angle steel and peak load belongs to the preset straight line slope range, then the maximum value within the preset slenderness ratio parameter range is selected.

[0116] If the slope of the fitted straight line corresponding to the curve of slenderness ratio of equal angle steel and peak load does not belong to the preset straight line slope range, then the middle value within the preset slenderness ratio parameter range shall be selected.

[0117] The slope of the fitted straight line corresponding to the curve of the equilateral angle steel reinforcement form and the peak load is compared with the preset straight line slope range.

[0118] If the slope of the fitted straight line corresponding to the curve of the equal angle steel reinforcement form and the peak load belongs to the preset straight line slope range, then the maximum value within the range of reinforcement form parameters is selected.

[0119] If the slope of the fitted straight line corresponding to the curve of the equal angle steel reinforcement form and the peak load does not fall within the preset straight line slope range, then the middle value within the range of reinforcement form parameters shall be selected.

[0120] In this embodiment, the preset slope range of the straight line is [0.2, 0.5].

[0121] It is understood that in this embodiment, if the slope of the fitted straight line corresponding to the curve of the slenderness ratio of the equal-sided angle steel and the peak load is 0.3, then the slenderness ratio of the equal-sided angle steel is selected as 130. If the slope of the fitted straight line corresponding to the curve of the reinforcement form of the equal-sided angle steel and the peak load is 0.1, then the reinforcement form parameter is selected as the clamp spacing of 500mm.

[0122] Specifically, this invention selects the slenderness ratio and reinforcement method of equilateral angle steel based on the curves of slenderness ratio and peak load, as well as the curves of reinforcement method and peak load. Traditional methods often rely on engineer experience or worst-case scenarios when selecting the slenderness ratio and reinforcement method, which can easily lead to over-design or insufficient adaptation. This invention uses a finite element model to obtain the peak load corresponding to different slenderness ratios and reinforcement methods, constructing curves of slenderness ratio versus peak load and curves of reinforcement method versus peak load. Then, linear fitting is performed on the curves, and the slope of the fitted line is used to determine the degree of influence of the parameters on the peak load. If the slope is large, it indicates that changes in the slenderness ratio or the clamp spacing have a significant impact on the peak load. In this case, the slenderness ratio and clamp spacing corresponding to the maximum peak load are selected to maximize the reinforcement effect. If the slope is gentle, it indicates that changes in the parameters have a weak impact on the peak load. In this case, intermediate parameter values ​​are selected to balance the reinforcement effect and cost. This avoids the limitations of empirical values ​​and achieves optimal matching of slenderness ratio and reinforcement method, balancing reinforcement reliability and engineering economy.

[0123] Specifically, the process of calculating the bearing capacity based on the slenderness ratio of the equilateral angle steel using the selected bearing capacity calculation formula includes the following steps:

[0124] The slenderness ratio of the equilateral angle steel is compared with a preset slenderness ratio comparison threshold.

[0125] If the slenderness ratio of the equilateral angle steel is less than the preset slenderness ratio comparison threshold, then the flexural buckling capacity is calculated by introducing a defect influence coefficient into the flexural buckling capacity formula.

[0126] If the slenderness ratio of the equilateral angle steel is greater than or equal to the preset slenderness ratio comparison threshold, then the defect influence coefficient and friction coefficient are introduced into the formula for flexural-torsional buckling bearing capacity to calculate the flexural-torsional buckling bearing capacity.

[0127] In this embodiment, the preset aspect ratio comparison threshold is selected within the range of [65, 75].

[0128] Specifically, the process of comparing the bearing capacity with the peak load obtained from the finite element model to determine whether to adjust the formula coefficients includes,

[0129] Obtain the absolute value of the difference between the bearing capacity and the peak load;

[0130] Calculate the ratio of the absolute value to the peak load;

[0131] If the ratio is greater than a preset ratio comparison threshold, it is determined that the formula coefficients should be adjusted.

[0132] In this embodiment, the preset ratio comparison threshold is selected within the range of [3%, 7%].

[0133] Specifically, the flexural buckling bearing capacity formula is calculated by introducing a defect influence coefficient, wherein the flexural buckling bearing capacity is equal to the product of the defect influence coefficient and the flexural buckling bearing capacity formula;

[0134] The formula for calculating flexural-torsional buckling bearing capacity introduces the defect influence coefficient and the reference value of the friction coefficient. The flexural-torsional buckling bearing capacity is equal to the product of the defect influence coefficient, the reference value of the friction coefficient, and the formula for flexural-torsional buckling bearing capacity.

[0135] In this embodiment, the formula for flexural buckling bearing capacity, which is equal to the product of the defect influence coefficient and the flexural buckling bearing capacity formula, is as follows:

[0136]

[0137] in, This represents the defect impact coefficient.

[0138] The formula for calculating the flexural-torsional buckling capacity, which is equal to the product of the defect influence coefficient and the reference value of the friction coefficient, and the formula for flexural-torsional buckling capacity, is as follows:

[0139]

[0140] in, This is the reference value for the coefficient of friction.

[0141] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for calculating the bearing capacity of a power transmission tower angle steel after non-destructive reinforcement, characterized in that, The application relates to a method for calculating the bearing capacity of an equal-angle steel, and belongs to the technical field of steel structure design. The method comprises the following steps: selecting a plurality of equal-angle steels in a preset slenderness ratio parameter range; carrying out geometric detection on the equal-angle steel samples to obtain initial bending amplitudes of the equal-angle steel samples; determining actual bearing capacities corresponding to the initial bending amplitudes of the equal-angle steel samples, and determining a defect influence coefficient according to a ratio of the actual bearing capacities to ideal bearing capacities; setting friction contact pairs between a reinforcing member and the equal-angle steel, between the equal-angle steel and a reinforcing plate, and between the reinforcing plate and the reinforcing member, obtaining a sliding amount through pre-simulation, comparing the sliding amount with an actual monitoring sliding amount, and determining a friction coefficient reference value; obtaining peak loads of each equal-angle steel in a reinforcing form parameter range through a finite element model; constructing a curve of the equal-angle steel slenderness ratio and the peak load and a curve of the equal-angle steel reinforcing form and the peak load; selecting the equal-angle steel slenderness ratio and the equal-angle steel reinforcing form according to the curve of the equal-angle steel slenderness ratio and the peak load and the curve of the equal-angle steel reinforcing form and the peak load; calculating the bearing capacity according to the equal-angle steel slenderness ratio, including introducing the defect influence coefficient into a bending buckling bearing capacity formula to calculate the bending buckling bearing capacity, or introducing the defect influence coefficient and the friction coefficient reference value into a bending-torsional buckling bearing capacity formula to calculate the bending-torsional buckling bearing capacity; 2. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, comparing the bearing capacity with the peak load obtained through the finite element model to determine whether to adjust the bearing capacity calculation formula coefficient.

3. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, The preset slenderness ratio parameter range is 50-130. The process of determining the actual bearing capacities corresponding to the initial bending amplitudes of the equal-angle steel samples comprises the following steps: obtaining a plurality of initial bending amplitudes of the equal-angle steel samples; calculating an average value of the plurality of initial bending amplitudes of the equal-angle steel samples; 4. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, constructing a three-dimensional geometric model through a finite element software, assigning defects according to the average value of the plurality of initial bending amplitudes of the equal-angle steel samples, and obtaining a peak load as an actual bearing capacity. The process of setting the friction contact pairs between the reinforcing member and the equal-angle steel, between the equal-angle steel and the reinforcing plate, and between the reinforcing plate and the reinforcing member, and obtaining the sliding amount through pre-simulation comprises the following steps: constructing a combined model of the equal-angle steel, the reinforcing plate and the reinforcing member in the finite element software; sequentially setting a plurality of friction coefficients between the reinforcing member and the equal-angle steel, between the equal-angle steel and the reinforcing plate, and between the reinforcing plate and the reinforcing member; setting a plurality of sliding amount monitoring points on edges of the reinforcing member and the equal-angle steel, the equal-angle steel and the reinforcing plate, and the reinforcing plate and the reinforcing member; 5. The method for calculating the load bearing capacity of a galvanized steel angle of a power transmission tower after non-destructive reinforcement according to claim 4, characterized in that, obtaining the sliding amount of each monitoring point corresponding to each friction coefficient. The process of comparing the sliding amount with the actual monitoring sliding amount to determine the friction coefficient reference value comprises the following steps: obtaining the actual monitoring sliding amount; selecting the sliding amount of the monitoring point corresponding to the friction coefficient with the smallest actual monitoring sliding amount difference; 6. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, determining the friction coefficient as the friction coefficient reference value.

7. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, The reinforcing form parameter range comprises a hoop spacing of 300 mm, 500 mm and 700 mm. The process of selecting the equal-angle steel slenderness ratio and the equal-angle steel reinforcing form according to the curve of the equal-angle steel slenderness ratio and the peak load and the curve of the equal-angle steel reinforcing form and the peak load comprises the following steps: fitting the curve of the equal-angle steel slenderness ratio and the peak load and the curve of the equal-angle steel reinforcing form and the peak load with straight lines respectively to obtain the slopes of the straight lines. The slope of the fitting straight line corresponding to the curve of the slenderness ratio of the equal angle steel and the peak load is compared with a preset slope range; If the slope of the fitting straight line corresponding to the curve of the slenderness ratio of the equal angle steel and the peak load belongs to the preset slope range, the maximum value in the preset slenderness ratio parameter range is selected; If the slope of the fitting straight line corresponding to the curve of the slenderness ratio of the equal angle steel and the peak load does not belong to the preset slope range, the intermediate value in the preset slenderness ratio parameter range is selected; The slope of the fitting straight line corresponding to the curve of the reinforcement form of the equal angle steel and the peak load is compared with a preset slope range; If the slope of the fitting straight line corresponding to the curve of the reinforcement form of the equal angle steel and the peak load belongs to the preset slope range, the maximum value in the reinforcement form parameter range is selected; If the slope of the fitting straight line corresponding to the curve of the reinforcement form of the equal angle steel and the peak load does not belong to the preset slope range, the intermediate value in the reinforcement form parameter range is selected.

8. The method for calculating the post-construction bearing capacity of a power transmission tower angle steel according to claim 7, characterized in that, The process of calculating the bearing capacity according to the slenderness ratio of the equal angle steel includes, The slenderness ratio of the equal angle steel is compared with a preset slenderness ratio comparison threshold value, If the slenderness ratio of the equal angle steel is less than the preset slenderness ratio comparison threshold value, a defect influence coefficient is introduced to the bending buckling bearing capacity formula to calculate the bending buckling bearing capacity; If the slenderness ratio of the equal angle steel is greater than or equal to the preset slenderness ratio comparison threshold value, a defect influence coefficient and a friction coefficient are introduced to the bending-torsional buckling bearing capacity formula to calculate the bending-torsional buckling bearing capacity.

9. The method for calculating the load bearing capacity of a power transmission tower angle steel after non-destructive reinforcement according to claim 1, characterized in that, The process of comparing the bearing capacity with the peak load obtained by the finite element model to determine whether to adjust the formula coefficient includes, An absolute value of the difference between the bearing capacity and the peak load is obtained; A ratio of the absolute value to the peak load is calculated; If the ratio is greater than a preset ratio comparison threshold value, it is determined that the formula coefficient is adjusted.

10. The method for calculating the load bearing capacity of a galvanized steel angle of a power transmission tower after non-destructive reinforcement according to claim 1, characterized in that, The defect influence coefficient is introduced to the bending buckling bearing capacity formula to calculate the bending buckling bearing capacity, wherein the bending buckling bearing capacity is equal to the product of the defect influence coefficient and the bending buckling bearing capacity formula; The defect influence coefficient and the friction coefficient reference value are introduced to the bending-torsional buckling bearing capacity formula to calculate the bending-torsional buckling bearing capacity, wherein the bending-torsional buckling bearing capacity is equal to the product of the defect influence coefficient, the friction coefficient reference value, and the bending-torsional buckling bearing capacity formula.

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