A method for calculating the axial compressive bearing capacity of corroded equilateral angle steel

Abstract

This invention discloses a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel, belonging to the field of civil engineering technology. The method includes the following steps: S1, parameter acquisition and foundation calculation; S2, calculation of uncorroded bearing capacity; S3, calculation of multi-factor influence coefficients; S4, calculation of bearing capacity after corrosion and output of operation and maintenance instructions. This invention employs the aforementioned method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. By incorporating key pitting corrosion parameters and adding a parameter for the ratio of corrosion rates between the two limbs, it integrates component geometry and corrosion parameters to construct a multi-factor coupled system. This accurately quantifies the impact of pitting corrosion, covers corrosion inhomogeneity, and improves the accuracy and comprehensiveness of calculating the axial compressive bearing capacity of corroded equilateral angle steel.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering technology, specifically relating to a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. Background Technology

[0002] Steel components are widely used in various building structures due to their good strength and ductility. With the continuous development of modern engineering construction in complex environments, this technology is applicable to civil engineering structures that are exposed to harsh environments with strong corrosiveness, such as marine and industrial atmospheres, and are subject to corrosion due to high salt spray and alternating wet and dry conditions. Specific examples include transmission towers, building steel structures, bridge supports, and port and dock load-bearing components. In particular, it provides a scientific basis for the accurate assessment of the load-bearing capacity of equilateral angle steel axially compressed components that have experienced pitting corrosion (the most common form of corrosion in steel structures, which easily leads to stress concentration and reduces the strength of steel) during service, supporting the safe operation and maintenance of structures and decision-making.

[0003] However, existing technologies have the following shortcomings: they only focus on a single corrosion rate design calculation model, and do not fully consider the stress concentration effect on steel caused by pitting corrosion (pit depth); they lack a systematic analysis of the uneven corrosion of the two limbs of angle steel, and have not formed an analysis system for the coupling effect between component geometric parameters (such as slenderness ratio and width-to-thickness ratio) and corrosion damage; the calculation accuracy of the axial compressive bearing capacity of corrosion equilateral angle steel under the combined action of multiple factors is limited, and its practicality and accuracy are insufficient.

[0004] Therefore, a new method is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. This method incorporates key pitting corrosion parameters, adds a corrosion rate ratio parameter between the two limbs, and integrates component geometry and corrosion parameters to construct a multi-factor coupled system. This method accurately quantifies the impact of pitting corrosion, covers corrosion inhomogeneity, and improves the accuracy and comprehensiveness of calculating the axial compressive bearing capacity of corroded equilateral angle steel.

[0006] To achieve the above objectives, this invention provides a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel, comprising the following steps: S1. Using detection equipment, obtain the corrosion parameters, geometric parameters, and boundary conditions of the corroded equilateral angle steel. The corrosion parameters include the original thickness, pit depth, and corrosion rate of the two limbs, and calculate the pit depth ratio and the corrosion rate ratio of the two limbs. The geometric parameters include the limb width and length. The boundary conditions are used to determine the calculated length of the component. S2. Based on the geometric parameters and steel yield strength in S1, calculate the slenderness ratio, overall stability coefficient, and axial compressive bearing capacity of the member in the uncorroded state. The formula is as follows: ; In the formula, The slenderness ratio of the component; The calculated length of the component; Let be the radius of gyration of the component's cross section; ; In the formula, The overall stability coefficient, Let be the cross-sectional area of ​​the angle steel. The yield strength of angle steel; The axial compressive bearing capacity of uncorroded equilateral angle steel; S3. Based on the preset corrosion-mechanical coupling model, substitute the parameters obtained in S1 to calculate each influence coefficient, including corrosion rate influence coefficient, pit depth influence coefficient, slenderness ratio influence coefficient, width-to-thickness ratio influence coefficient and corrosion difference influence coefficient between the two limbs. S4. Calculate the axial compressive bearing capacity of the corroded equilateral angle steel and link it with the structural safety monitoring system to output operation and maintenance instructions.

[0007] Preferably, in S1, the formula for calculating the pit depth ratio is: ; In the formula, This is the original thickness; This represents the depth of the erosion pit. The ratio of corrosion rates between the two limbs is given by the following formula: ; In the formula, For the corrosion rate of the two limbs, The ratio of corrosion rates between the two limbs.

[0008] Preferably, the detection equipment in S1 includes an ultrasonic thickness gauge, a three-dimensional corrosion morphology scanner, and a stress-strain gauge; the corrosion rate is the mass loss rate of the corrosion area of ​​the angle steel.

[0009] Preferably, the corrosion rate influence coefficient mentioned in S3 is calculated using the following formula: ; In the formula, The corrosion rate of the angle steel; The coefficient representing the influence of corrosion rate; The formula for calculating the influence coefficient of pit depth is as follows: ; In the formula, This is the ratio of the pit depth of the angle steel to the thickness of the angle steel when it is not corroded; This represents the influence coefficient of pit depth.

[0010] Preferably, the slenderness ratio influence coefficient mentioned in S3 is calculated using the following formula: ; In the formula, The slenderness ratio of the angle steel; The slenderness ratio influence coefficient; The formula for the width-to-thickness ratio influence coefficient is: ; In the formula, The width-to-thickness ratio of the angle steel; The aspect ratio influence coefficient; The coefficient of influence of corrosion difference between the two limbs is given by the following formula: ; In the formula, The ratio of corrosion rates between the two limbs; The coefficient representing the difference in corrosion between the two limbs.

[0011] Preferably, the axial compressive bearing capacity of the corroded equilateral angle steel in S4 is calculated using the following formula: ; In the formula, This refers to the axial compressive bearing capacity of the equilateral angle steel after corrosion. The coefficient representing the influence of corrosion rate; The coefficient representing the influence of pit depth; The slenderness ratio influence coefficient; The aspect ratio influence coefficient; The coefficient representing the difference in corrosion between the two limbs.

[0012] Preferably, the maintenance instructions in S4 include: like Component working load, generate "continuous operation and maintenance" instructions; like The component's working load is marked as "to be reinforced / replaced" and a component replacement specification suggestion is output.

[0013] Therefore, the present invention employs the above-mentioned method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. Compared with the prior art, the technical solution of the present invention has the following beneficial effects: (1) By adopting the technical means of incorporating the key parameter of pitting corrosion (the ratio of pit depth to uncorroded thickness) for the first time, the technical problem of difficulty in accurately calculating the strength reduction caused by pitting corrosion was overcome, thereby achieving the technical effect of accurately quantifying the impact of pitting corrosion on bearing capacity. (2) By adopting the technical means of adding the parameter of "corrosion ratio of two limbs", the technical problem of ignoring the uneven corrosion of the two limbs of the angle steel in the existing technology is overcome, thereby achieving the technical effect of covering the impact of uneven corrosion on the load-bearing capacity assessment. (3) By adopting the technical means of integrating the geometric characteristics of the component (slenderness ratio, width-to-thickness ratio) and corrosion parameters to construct a multi-factor coupled calculation system, the technical problem of the limitation of single corrosion rate calculation is overcome, and thus the technical effect of significantly improving the accuracy and comprehensiveness of the calculation of the axial compressive bearing capacity of corrosion equilateral angle steel is achieved.

[0014] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of pitting corrosion distribution on the surface of a corroded equilateral angle steel, according to an embodiment of the method for calculating the axial compressive bearing capacity of corroded equilateral angle steel of the present invention. Figure 2 This is a schematic diagram of the cross-sectional corrosion distribution of an equilateral angle steel according to an embodiment of the method for calculating the axial compressive bearing capacity of a corroded equilateral angle steel according to the present invention. Figure 3 This is a three-dimensional view of a corroded equilateral angle steel according to an embodiment of the method for calculating the axial compressive bearing capacity of corroded equilateral angle steel of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used in the present invention should have the ordinary meaning understood by those skilled in the art.

[0017] Example 1 like Figures 1-3 As shown, this embodiment provides a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. It should be understood that the specific parameters, models and protocols mentioned in this embodiment are merely examples to help those skilled in the art understand the present invention, and are not intended to limit the present invention.

[0018] This invention provides a method for calculating the axial compressive bearing capacity of corroded equilateral angle steel, which specifically includes the following steps: S1. The equilateral angle steel used in the web members of a power transmission tower near a port in the southeast coastal area has been exposed to the marine atmosphere for a long time. Under the action of high salt spray, strong ultraviolet radiation and alternating wet and dry conditions, it has undergone significant corrosion, and the corrosion mode is mainly pitting corrosion.

[0019] The equilateral angle steel web members of the power transmission towers in the southeast coastal area were inspected using an ultrasonic thickness gauge and a 3D corrosion morphology scanner. The original thickness of the angle steel was determined using an ultrasonic thickness gauge. pit depth The formula for calculating the pit depth ratio is: ; The surface of the two legs of the angle steel was scanned using a corrosion morphology 3D scanner to obtain the mass loss rate of the corrosion area of ​​the two legs. The corrosion rate ratio is calculated using the following formula: ; In the formula, The ratio of corrosion rates between the two limbs. ; Synchronous recording of angle steel leg width ,length The calculated length of the component is determined by confirming the component boundary conditions (hinged / rigid) using a stress-strain gauge. S2. The angle steel cross-sectional dimensions and yield strength of Q355 steel collected in S1. Input the data into a dedicated terminal for assessing the load-bearing capacity of corroded components. The terminal then uses the built-in database of the "Steel Structure Design Standard" (GB 50017-2017) to calculate the slenderness ratio. The formula is as follows: ; In the formula, The slenderness ratio of the component; The calculated length of the component; Let be the radius of gyration of the component's cross section; By matching the overall stability coefficient corresponding to the slenderness ratio The bearing capacity of the uncorroded angle steel under axial compression is calculated using the following formula: ; In the formula, The overall stability coefficient, Let be the cross-sectional area of ​​the angle steel. The yield strength of angle steel; The axial compressive bearing capacity of uncorroded equilateral angle steel; S3. The evaluation terminal, based on a preset corrosion-mechanical coupling model, automatically substitutes the parameters collected in S1 and calculates sequentially: Calculate the influence coefficient of corrosion rate The terminal calls the fitting model of corrosion rate and bearing capacity attenuation under marine atmospheric environment, and the formula is: ; In the formula, The corrosion rate of the angle steel; The coefficient representing the influence of corrosion rate; Based on the pitting corrosion stress concentration test database, the terminal calculates the influence coefficient of pit depth on the bearing capacity of equal-angle steel, using the following formula: ; In the formula, This is the ratio of the pit depth of the angle steel to the thickness of the angle steel when it is not corroded; The coefficient representing the influence of pit depth; By combining the correlation model of component geometric parameters and stability performance, the slenderness ratio influence coefficient and width-to-thickness ratio influence coefficient are calculated. The formula is as follows: ; In the formula, The slenderness ratio of the angle steel; The slenderness ratio influence coefficient; The formula for the width-to-thickness ratio influence coefficient is: ; In the formula, The width-to-thickness ratio of the angle steel; The aspect ratio influence coefficient; Based on the mechanical simulation model of uneven stress on the two limbs of the terminal, the influence coefficient of the corrosion difference between the two limbs of the angle steel on the bearing capacity of the equilateral angle steel is calculated, and the formula is as follows: ; In the formula, The ratio of corrosion rates between the two limbs; The coefficient representing the influence of corrosion difference between the two limbs; S4. Calculate the bearing capacity of corroded equal angle steel under axial compression. The formula is: ; In the formula, This represents the axial compressive bearing capacity of the equilateral angle steel after corrosion.

[0020] And link it with the transmission tower structure safety monitoring system: like If the component's working load is applied, the system generates a "continuous operation and maintenance" technical instruction; if If the component is under working load, the system marks the web member as "needs reinforcement / replacement" and outputs targeted component replacement specification suggestions.

[0021] Therefore, the present invention adopts the above-mentioned method for calculating the axial compressive bearing capacity of corroded equilateral angle steel. This method incorporates key pitting corrosion parameters, adds a corrosion rate ratio parameter between the two limbs, integrates component geometry and corrosion parameters to construct a multi-factor coupling system, accurately quantifies the impact of pitting corrosion, covers corrosion inhomogeneity, and improves the accuracy and comprehensiveness of calculating the axial compressive bearing capacity of corroded equilateral angle steel.

[0022] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for calculating the axial compressive bearing capacity of corroded equilateral angle steel, characterized in that, Includes the following steps: S1. Using detection equipment, obtain the corrosion parameters, geometric parameters, and boundary conditions of the corroded equilateral angle steel. The corrosion parameters include the original thickness, pit depth, and corrosion rate of the two limbs, and calculate the pit depth ratio and the corrosion rate ratio of the two limbs. The geometric parameters include the limb width and length. The boundary conditions are used to determine the calculated length of the component. S2. Based on the geometric parameters and steel yield strength in S1, calculate the slenderness ratio, overall stability coefficient, and axial compressive bearing capacity of the member in the uncorroded state. The formula is as follows: ； In the formula, The slenderness ratio of the component; The calculated length of the component; Let be the radius of gyration of the component's cross section; ； In the formula, The overall stability coefficient, Let be the cross-sectional area of ​​the angle steel. The yield strength of angle steel; The axial compressive bearing capacity of uncorroded equilateral angle steel; S3. Based on the preset corrosion-mechanical coupling model, substitute the parameters obtained in S1 to calculate each influence coefficient, including corrosion rate influence coefficient, pit depth influence coefficient, slenderness ratio influence coefficient, width-to-thickness ratio influence coefficient and corrosion difference influence coefficient between the two limbs. S4. Calculate the axial compressive bearing capacity of the corroded equilateral angle steel and link it with the structural safety monitoring system to output operation and maintenance instructions.

2. The method for calculating the axial compressive bearing capacity of corroded equilateral angle steel according to claim 1, characterized in that, In S1, the formula for calculating the pit depth ratio is: ； In the formula, This is the original thickness; This represents the depth of the erosion pit. The ratio of corrosion rates between the two limbs is given by the following formula: ； In the formula, Corrosion rate of both limbs; The ratio of corrosion rates between the two limbs.

3. The method for calculating the axial compressive bearing capacity of corroded equilateral angle steel according to claim 2, characterized in that, The detection equipment described in S1 includes an ultrasonic thickness gauge, a three-dimensional corrosion morphology scanner, and a stress-strain gauge; the corrosion rate is the mass loss rate of the corrosion area of ​​the angle steel.

4. The method for calculating the axial compressive bearing capacity of corroded equilateral angle steel according to claim 3, characterized in that, The corrosion rate influence coefficient mentioned in S3 is calculated using the following formula: ； In the formula, The corrosion rate of the angle steel; The coefficient representing the influence of corrosion rate; The formula for calculating the influence coefficient of pit depth is as follows: ； In the formula, This is the ratio of the pit depth of the angle steel to the thickness of the angle steel when it is not corroded; This represents the influence coefficient of pit depth.

5. The method for calculating the axial compressive bearing capacity of corroded equilateral angle steel according to claim 4, characterized in that, The formula for calculating the slenderness ratio influence coefficient mentioned in S3 is as follows: ； In the formula, The slenderness ratio of the angle steel; The slenderness ratio influence coefficient; The influence coefficient of width-to-thickness ratio is calculated using the following formula: ； In the formula, The width-to-thickness ratio of the angle steel; The aspect ratio influence coefficient; The coefficient of influence of corrosion difference between the two limbs is given by the following formula: ； In the formula, The ratio of corrosion rates between the two limbs; The coefficient representing the difference in corrosion between the two limbs.

6. The method for calculating the axial compressive bearing capacity of a corroded equilateral angle steel according to claim 5, characterized in that, The axial compressive bearing capacity of the corroded equilateral angle steel in S4 is calculated using the following formula: ； In the formula, This refers to the axial compressive bearing capacity of the equilateral angle steel after corrosion. The coefficient representing the influence of corrosion rate; The coefficient representing the influence of pit depth; The slenderness ratio influence coefficient; The aspect ratio influence coefficient; The coefficient representing the difference in corrosion between the two limbs.

7. The method for calculating the axial compressive bearing capacity of a corroded equilateral angle steel according to claim 6, characterized in that, The maintenance instructions described in S4 include: like Component working load, generate "continuous operation and maintenance" command; like The component's working load is marked as "to be reinforced / replaced" and a component replacement specification suggestion is output.

8. A computer device, characterized in that, include: A processor configured to be coupled to a memory, read and execute instructions and / or program code in the memory to perform the method as described in any one of claims 1-7.

9. A computer-readable medium, characterized in that, The computer-readable medium stores computer program code that, when executed on a computer, causes the computer to perform the method as described in any one of claims 1-7.

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