Round section eccentric tension checking calculation method based on allowable stress method and related device

Abstract

The invention discloses a circular section eccentric tension checking calculation method based on an allowable stress method and a related device, and the method comprises the steps: building a material database, defining the physical properties and mechanical properties of concrete, reinforcing steel bars and other engineering materials, and allowing a user to customize the allowable stress value of the materials; inputting parameters required by item calculation in the parameter input interface; based on the defined material database and the input parameters, material parameter indexing, section parameter compiling and large and small eccentric tension type judgment are automatically conducted, corresponding large and small eccentric tension calculation models are selected according to the judgment result, and large and small eccentric tension checking calculation is conducted. The method is suitable for the tensile working condition of the circular cross section in rail transit substructure checking calculation, accurate checking calculation is conducted according to the eccentric tensile condition, a more reliable basis is provided for design of an engineering structure, a powerful tool is provided for bridge design in the railway and rail transit industry, structural design and checking calculation are conducted more scientifically, and the working efficiency is improved. Therefore, the engineering safety is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of rail transit bridge design, and more specifically, relates to a method for checking eccentric tension of a circular cross-section based on the allowable stress method. Background Art

[0002] In the field of structural engineering, circular cross-section structures are highly favored due to their good mechanical properties and wide application scenarios. However, when these structures are subjected to eccentric tensile forces, their stress states become complex and difficult to predict, posing a severe challenge to the safety and stability of the structures. Traditional checking methods often adopt highway codes and follow the design method of the ultimate limit state of bearing capacity for cross-section checking, while ignoring the allowable stress design method used in the circular eccentric tension condition of railway or rail transit bridges, resulting in potential safety hazards in the design results. The allowable stress method is a commonly used structural analysis method. Based on the allowable stress value of the material, this method calculates the stress state of the structure under specific loads and compares it with the allowable stress to evaluate the safety of the structure. For the checking of circular cross-section structures under eccentric loads, the existing technology usually involves complex stress analysis and calculations, including determining the position of the centroid axis of the transformed cross-section, calculating the eccentricity, analyzing the cross-section stress distribution, etc. In addition, various factors such as material properties, cross-section dimensions, and reinforcement methods need to be considered. To address this challenge, the present invention proposes a method for checking eccentric tension of a circular cross-section based on the allowable stress method. By deriving an eccentric tension formula applicable to circular cross-sections based on the basic principle of the allowable stress method, a systematic checking process is established, greatly improving the accuracy of checking and design efficiency. Summary of the Invention

[0003] Aiming at the above defects or improvement requirements of the existing technology, the present invention provides a method for checking eccentric tension of a circular cross-section based on the allowable stress method and related devices. On a computer platform, using computer language, it meets the requirements of rail transit bridge design, is applicable to the eccentric tension strength checking of circular cross-sections of high-speed railway and rail transit industry elevated bridge piers, and is especially applicable to the tensile condition of circular members during the seismic-related checking of bridge structures. By combining the principle of the allowable stress method and considering the particularity of the circular cross-section, a checking process is established. This process can not only accurately evaluate the stress state of components under eccentric tension, but also provide scientific design guidance for engineers, thereby improving the overall performance and reliability of the structure.

[0004] To achieve the object of the present invention, according to the first aspect of the present invention, a method for checking eccentric tension of a circular cross-section based on the allowable stress method is provided, including the following specific steps:

[0005] S100: Establish a material database, define the physical properties and mechanical characteristics of engineering materials such as concrete and steel bars, and allow users to customize the allowable stress values of materials;

[0006] S200: Input the parameters required for project calculation in the parameter input interface;

[0007] S300: Based on the material database defined in step S100 and the parameters input in step S200, automatically perform material parameter indexing, cross-section parameter compilation, and small and large eccentric tension type discrimination, and select the corresponding small and large eccentric tension calculation models according to the discrimination results to perform small eccentric tension checking and large eccentric tension checking.

[0008] Further, the parameters in step S200 include load combination types, member dimensions, material types, reinforcement data, and combined internal forces.

[0009] Further, the small eccentric tension checking in step S300 includes checking the maximum steel bar stress on the tension side of the section, and the specific calculation process is as follows:

[0010] Calculate the moment of inertia of the steel bar Is:

[0011]

[0012] where As is the steel bar area, r g is the distance from the center of the member to the centroid of the steel bar;

[0013] The maximum tensile stress of the steel bar is:

[0014] σ s =N / A s +M y / (I s )≤ [σ s (2)

[0015] where N is the calculated axial tension, M is the calculated bending moment, As is the steel bar area, Is is the moment of inertia of the steel bar section, and y is the distance from the section centroid to the center of the outermost row of steel bars.

[0016] Further, the large eccentric tension checking in step S300 includes the calculation of determining the compression angle, the maximum stress of the concrete in the compression zone, and the stress of the steel bar in the compression zone.

[0017] Further, the compression angle α is calculated as follows:

[0018] The position of the central axis of the circular section is related to the axial force F, eccentricity e, radius R, reinforcement ratio, etc., and its position can be determined by the following equation:

[0019] ∑∫σdA=F (3)

[0020] ∑∫σρdA = M = Fe (4)

[0021] where σ is the stress function; dA is the area element; ρ is the distance from dA to the centroid; ∫ is the integral sign, and its scope of action is to only consider the compression zone for concrete and the whole for steel bars, obtaining:

[0022]

[0023] V = 2sin 3 α - 3αcosα + 3sinαcos 2 α (6)

[0024] W = 12α - 3sin4α - 32sin 3 αcosα (7)

[0025] Q = 3πcosα (8)

[0026] where e is the eccentricity for calculating the axial tension F; M is the calculated bending moment, calculated as F·e; R is the radius of the cross-section of the member; r g is the distance from the centroid of the steel bars to the center of the cross-section; n is the ratio of the elastic modulus of the steel bars to the compressive elastic modulus of the concrete; K is a coefficient μ is the reinforcement ratio μ = A g / πR 2 ; α is half of the central angle corresponding to the compression zone; W, V, and Q are all functions of the central angle α;

[0027] By initially assigning a value to the angle α through the program, equations (6) to (8) can all be calculated based on the assigned angle α. By setting the error between the left and right sides of equation (5) to be 10 5 , with the iterative step size of the angle α being 0.0001 degrees, the program, based on the initial assignment and the iterative step size, iterates in a loop to make the two sides of equation (5) approximately equal. At this time, α is the actual half central angle α of the force-bearing situation sought. Based on it, the position of the neutral axis is determined, and the length of the compression zone is obtained as 2KR.

[0028] Furthermore, based on the compression angle α, check the maximum stress of the concrete in the compression zone and the stress of the steel bars:

[0029] Then, according to equations (3) to (4), the maximum stress of the concrete in the compression zone is obtained as:

[0030]

[0031] Then, according to equation (9), the stress of the steel bars in the compression zone is obtained as:

[0032]

[0033] Furthermore, it also includes: calculating the crack width according to project requirements.

[0034] The present invention also provides a data processing device for checking eccentric tension of a circular section based on the allowable stress method, which is used to implement the steps of a method for checking eccentric tension of a circular section based on the allowable stress method as described above, including:

[0035] A material database module, which is used to establish and maintain the properties of engineering materials and provide functions for retrieving and updating material parameters;

[0036] A parameter input module, which is used to input various parameters required for project calculation and perform verification;

[0037] A calculation and analysis module, which is used to perform material parameter indexing, cross-section parameter compilation, large and small eccentricity discrimination, and corresponding tension calculation, and perform crack width calculation as required;

[0038] A result output module, which is used to output the analysis results of the check calculation.

[0039] As another aspect of the present invention, the present invention also provides an electronic device, including:

[0040] At least one memory, which is used to store computer programs;

[0041] At least one processor, which is used to implement the steps of a method for checking eccentric tension of a circular section based on the allowable stress method as described in any one of claims 1 to 7 when executing the computer program.

[0042] The present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of a method for checking eccentric tension of a circular section based on the allowable stress method as described above.

[0043] Generally speaking, compared with the prior art through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0044] 1. The method for checking eccentric tension of a circular section based on the allowable stress method of the present invention combines the principle of the allowable stress method with the characteristics of a circular section, and performs accurate checking for the eccentric tension situation. Through fine mathematical internal force analysis and strict theoretical derivation, it can more truly reflect the stress distribution and deformation of the circular section under the eccentric tension state, greatly improving the accuracy of the checking calculation, and thus providing a more reliable basis for the design of engineering structures.

[0045] 2. The eccentric tension checking method for circular sections based on the allowable stress method of the present invention provides an intuitive and easy-to-use parameter input interface for inputting various parameters required for project calculation, enabling designers to complete complex large and small eccentric tension checks after simple parameter input, reducing design mistakes caused by incorrect parameter input, and improving work efficiency and design quality.

[0046] 3. The eccentric tension checking method for circular sections based on the allowable stress method of the present invention first introduces the allowable stress algorithm in the checking of the lower structure of rail transit, filling the technical gap in the railway and rail transit industry fields, providing a powerful tool for engineers in this field, enabling them to carry out structural design and checking more scientifically, and thus ensuring the safety and stability of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is the flowchart of the eccentric tension checking method for circular sections based on the allowable stress method in the embodiment of the present invention;

[0048] Figure 2 is the flowchart of the large and small eccentric tension checks in the embodiment of the present invention;

[0049] Figure 3 is the schematic diagram of large eccentric tension of circular sections in the embodiment of the present invention;

[0050] Figure 4 is the program parameter input interface of Embodiment 2 of the present invention;

[0051] Figure 5 is the program calculation result interface of Embodiment 2 of the present invention;

[0052] Figure 6 is the schematic diagram of the structure of the data processing device of the eccentric tension checking method for circular sections based on the allowable stress method in the embodiment of the present invention;

[0053] Figure 7 is the schematic diagram of the structure of the electronic device of the eccentric tension checking method for circular sections based on the allowable stress method in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0054] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0055] It should be noted that the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] In this patent, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0057] The following describes, through an embodiment, a method for checking eccentric tension of a circular cross-section based on the allowable stress method provided by the present application.

[0058] Embodiment 1

[0059] Please refer to Figure 1 , Figure 1 which is a flowchart of a method for checking eccentric tension of a circular cross-section based on the allowable stress method provided by the embodiment of the present application. In this embodiment, the method includes:

[0060] S100: Establish a material database to define the properties of engineering materials such as concrete and steel bars, including physical properties (such as density, coefficient of thermal expansion, etc.) and mechanical properties (such as compressive strength, tensile strength, elastic modulus, ultimate tensile strength, etc.). In addition, the user can also customize the allowable stress value and other properties of the material according to the particularity of the project.

[0061] S200: Input the parameters required for project calculation in the parameter input interface, including the following aspects:

[0062] Load combination type: Determine the load combination acting on the member, and select different types of load combinations in the parameter input interface, such as main force, main force + additional force, main force + special force, seismic force and other combination forms to simulate different working conditions;

[0063] Member size: Accurately input the specific size of the member, such as the diameter and length of the member;

[0064] Material type: Parameters such as concrete strength grade and steel bar strength grade;

[0065] Reinforcement data: Input information such as the appropriate diameter and quantity of steel bars;

[0066] Combined internal forces: Enter the internal forces and combined forces generated by various load combinations, such as combined axial tension, combined bending moment, etc.

[0067] The parameter entry interface is intuitive and easy to use. Users can conveniently and quickly set all necessary calculation parameters, while reducing the possibility of human errors.

[0068] S300: Based on steps S100 and S200, implement material parameter indexing, cross-section parameter compilation, distinguish between large and small eccentric tension types, and select the corresponding large or small eccentric tension calculation model according to the discrimination result for accurate mechanical analysis and calculation.

[0069] S301: Material parameter indexing: Based on the material database established in step S100, it can quickly retrieve the required material properties, thus ensuring that each calculation has accurate material data support.

[0070] S302: Cross-section parameter compilation: Generate detailed cross-section characteristics based on the input member dimensions and other relevant information, such as geometric parameters like cross-sectional area, moment of inertia, etc., and the comprehensive mechanical properties considering the reinforcement situation.

[0071] S303: Large and small eccentricity discrimination: Based on the input combined internal forces and other relevant information, conduct a force analysis on the member and determine whether it belongs to the large eccentric tension model or the small eccentric tension model.

[0072] S304: Tension calculation: Conduct accurate mechanical analysis according to the discriminated calculation model (large or small eccentric tension model). If it is in the small eccentric tension state, the entire cross-section of the member is in tension. According to mechanical equilibrium, only the maximum steel stress on the tension side of the cross-section needs to be checked and discriminated. If it is in the large eccentric tension state, both tensile and compressive parts appear on the member cross-section. According to mechanical equilibrium, calculate the compressive angle α for large eccentric tension. First, assume a constant value for assignment, and calculate the actual compressive angle α through iteration based on the equation. Calculate the maximum compressive stress of the concrete in the compression zone through this compressive angle α, then convert the compressive stress of the concrete in the compression zone to the compressive steel stress, and at the same time calculate the maximum steel stress on the tension side. As Figure 5 shown, it is the flow chart for checking large and small eccentric tension of the member.

[0073] (1) Small eccentric tension calculation

[0074] In the analysis of structural mechanics, for the case of small eccentric tension, its force analysis is relatively direct and simple. The specific calculation process is as follows:

[0075] Calculate the steel inertia moment Is:

[0076]

[0077] where As is the steel area, rg It is the distance from the center of the component to the centroid of the steel bar.

[0078] The maximum tensile stress of the steel bar is:

[0079] σ s = N / A s + M y / (I s ) ≤ [σ s (2)

[0080] Wherein, N is the calculated axial tensile force, M is the calculated bending moment, As is the area of the steel bar, Is is the moment of inertia of the steel bar section, and y is the distance from the centroid of the section to the centroid of the steel bar.

[0081] Check whether the stress of the steel bar exceeds the allowable value:

[0082] Verify the calculated steel bar stress σ s Whether it is less than or equal to the allowable tensile stress [σ s . If σ s ≤ [σ s , it means that the safety of the steel bar is guaranteed; otherwise, it is necessary to adjust the steel bar reinforcement amount or other parameters to meet the requirements.

[0083] (2) Large eccentric tension calculation

[0084] Compared with the small eccentric case, the stress state of large eccentric tension is more complex. Taking the large eccentric tension of a circular section as an example, part of the derivation process is as follows (i.e., e > k):

[0085] Figure 6 It is a schematic diagram of large eccentric tension of a circular section. The position of the central axis of the circular section is related to the axial force F, the eccentricity e, the radius R, the reinforcement ratio, etc., and its position can be determined by the following equation.

[0086] ∑∫σdA = F (3)

[0087] ∑∫σρdA = M = Fe (4)

[0088] Wherein, σ is the stress function; dA is the area element; ρ is the distance from dA to the centroid; ∫ is the integral sign, and its scope of action is only the compression zone for concrete and all for steel bars. We get:

[0089]

[0090] V = 2sin 3 α - 3αcosα + 3sinαcos 2 α (6)

[0091] W = 12α - 3sin4α - 32sin 3α cos α (7)

[0092] Q = 3π cos α (8)

[0093] Wherein, e is the eccentricity for calculating the axial tensile force F; M is the calculated bending moment, calculated as F·e; R is the radius of the cross-section of the member; r g is the distance from the centroid of the steel bar to the center of the cross-section; n is the ratio of the elastic modulus of the steel bar to the compressive elastic modulus of the concrete; K is a coefficient μ is the reinforcement ratio μ = A g / πR 2 ; α is half of the central angle corresponding to the compression zone.

[0094] Wherein, e / R on the left side of equation (5) is called the eccentricity ratio, and its value is known. W, V, and Q on the right side of equation (5) are all functions of the central angle α, and the angle α is an unknown quantity to be determined. By initially assigning a value to the angle α through the program, equations (6) to (8) can all be calculated based on the assigned value of the angle α. By setting the error between the left and right sides of equation (5) to be equal to 10 5 , with the iteration step size of the angle α being 0.0001 degrees, the program iterates cyclically according to the initial assignment and the iteration step size to make the two sides of equation (5) basically equal. At this time, α is the actual half central angle α of the force-bearing condition sought. Based on it, the position of the neutral axis is determined, and the length of the compression zone obtained is 2KR.

[0095] Then, according to equations (3) to (4), the maximum stress of the concrete in the compression zone is obtained as follows:

[0096]

[0097] Then, according to equation (9), the stress of the steel bar in the compression zone is obtained as follows:

[0098]

[0099] Furthermore, a method for checking eccentric tension of a circular cross-section based on the allowable stress method provided by the present invention further includes calculating the crack width according to project requirements and predicting the possible crack conditions of the member to ensure the long-term performance of the structure. The specific contents are as follows:

[0100] Step 1: Determine the steel bar stress: First, it is necessary to calculate the steel bar stress σ s under the long-term action of the load, which can be obtained through the mechanical analysis calculation in the eccentric tension state mentioned in the above embodiments.

[0101] Step 2: Select parameters: Select appropriate geometric parameters such as the steel bar cover thickness, steel bar diameter, and steel bar spacing according to specific design requirements and actual conditions.

[0102] Step 3: Substitute the above parameters into the formula for calculating the crack width of reinforced concrete structures in the Code for Design of Concrete Structures of Railway Bridges and Culverts (TB 10092 - 2017) to obtain the predicted maximum crack width.

[0103] Step 4: Check the limit value: Finally, compare the calculated value with the allowable maximum crack width specified in the code. If it exceeds the limit value, the design parameters (such as increasing the amount of steel bars, reducing the spacing of steel bars, etc.) need to be adjusted to meet the requirements of the crack width.

[0104] The method for checking eccentric tension of circular cross - sections based on the allowable stress method provided by this patent not only provides a complete theoretical framework for engineers, but also greatly simplifies the actual operation process and improves work efficiency and design quality by combining advanced numerical calculation techniques and graphical user interfaces.

[0105] The following further illustrates a method for checking eccentric tension of circular cross - sections based on the allowable stress method provided by this application through another specific embodiment.

[0106] Embodiment 2

[0107] Taking a certain project as an example for checking, the diameter of the circular cross - section is 1.2 m, the concrete strength grade is C35, the steel bar strength grade is HRB500, the cross - section reinforcement is 24 steel bars with a diameter of 28 mm, the distance from the centroid of the steel bars to the edge of the member is 75 mm, the combined axial tension under the frequent earthquake condition is 841.7 KN, and the combined bending moment is 622.4 KN·m.

[0108] Taking the project in Embodiment 2 as an example, the system can automatically complete the following tasks:

[0109] Step 1: Retrieve the performance parameters of C35 concrete and HRB500 steel bars from the material database.

[0110] Step 2: Compile the cross - section parameters according to the parameters input by the user (such as the diameter of the circular cross - section is 1.2 m, the cross - section reinforcement is 24 steel bars with a diameter of 28 mm, etc.). As Figure 4 shown, it is the interface for entering program parameters in Embodiment 2 of the present invention;

[0111] Step 3: Determine the large and small eccentricities according to the combined axial tension and combined bending moment under the frequent earthquake condition.

[0112] Step 4: Select the large - eccentricity tension calculation model for mechanical analysis according to the discrimination result, and calculate the compression angle α, the maximum stress of the compressed concrete, the stress of the steel bars, etc. As Figure 5 shown, it is the interface for the program calculation results in the embodiment of the present invention.

[0113] Step 5: Calculate the crack width as needed to predict the possible crack conditions of the component.

[0114] Step 6: Output the calculation and analysis results in the form of charts, reports, etc., for the convenience of users to view and understand. Example 3

[0115] An embodiment of the present invention provides an eccentric tension checking data processing device for a circular cross-section based on the allowable stress method, which is used to implement the steps of the above-mentioned eccentric tension checking method for a circular cross-section based on the allowable stress method. The system may include:

[0116] Material database module: Establish and maintain a performance database of engineering materials such as concrete and steel bars, including physical properties, mechanical characteristics, and user-defined allowable values, etc., providing an accurate data basis for subsequent calculations, and providing retrieval and update functions for material parameters to ensure the accuracy of the material data used in the calculation process.

[0117] Parameter input module: Provide an intuitive and easy-to-use parameter input interface, allowing users to input various parameters required for project calculations, such as load combination types, component dimensions, material types, reinforcement data, and combined internal forces, etc., and providing a parameter verification function to ensure that the data input by users meets the specifications and requirements.

[0118] Calculation and analysis module: Based on the data provided by the material database module and the parameter input module, perform material parameter indexing, cross-section parameter compilation, and large and small eccentricity discrimination. And according to the discrimination results, select the corresponding calculation model (large eccentricity or small eccentricity) for accurate mechanical analysis. Provide small eccentric tension calculation and large eccentric tension calculation functions, including iterative calculation of the compression angle α, calculation of the maximum stress of the compressed concrete, and calculation of the steel bar stress, etc. Calculate the crack width as needed to predict the possible crack conditions of the component.

[0119] Result output module: Output the calculation and analysis results in the form of charts, reports, etc., for the convenience of users to view and understand and provide a result comparison function, allowing users to compare the calculation results with the specifications or design requirements to determine whether the component meets the design requirements.

[0120] The system of this embodiment integrates functions such as material database, parameter input, calculation and analysis, and result output, realizing the automation and intelligence of eccentric tension checking for circular cross-sections, and providing an intuitive and easy-to-use user interface and help documents, facilitating operations such as parameter input and result viewing for users.

[0121] According to the above examples, the present application further provides an electronic device, including: a memory, a processor, and a program or instruction stored on the memory and executable on the processor. When the processor executes the program or instruction, further, the data device of the present invention may further include a communication interface and a bus. As Figure 4 shown, it is a schematic structural diagram of the electronic device provided by the present invention, including: at least one processor 10, at least one memory 11, a communication interface 12, and a bus 13.

[0122] Among them, the processor 10, the memory 11, and the communication interface 12 complete mutual communication through the bus 13. The communication interface 12 is used for information transmission between the data device and the database device; the memory 11 stores a program or instruction executable on the processor 10. When the processor 10 executes the program or instruction, the steps of the above-mentioned method for checking eccentric tension of a circular cross-section based on the allowable stress method are realized.

[0123] In a possible implementation manner, the memory 11 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system, and application programs required for at least one function, etc.; the data storage area may store data created during use.

[0124] In addition, the memory 11 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device or other volatile solid-state storage devices.

[0125] The communication interface 12 may be an interface of a communication module, and is used for connecting to other devices or systems.

[0126] Of course, it should be noted that Figure 6 the structure shown does not constitute a limitation on the electronic device in the embodiments of the present application. In practical applications, the electronic device may include more or fewer components than Figure 6 shown, or combine some components.

[0127] Embodiments of the present invention further provide a computer-readable storage medium according to the above examples. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned method for checking eccentric tension of a circular cross-section based on the allowable stress method are realized.

[0128] The computer-readable storage medium may include: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0129] Combined with the above embodiments, the present invention is applied on a computer platform, using computer language, to meet the requirements of rail transit bridge design. It is applicable to the eccentric tensile strength calculation of the circular cross-section of piers of elevated bridges in the railway and rail transit industries, especially applicable to the tensile working conditions of circular members that occur during the seismic-related calculation of bridge structures. The calculation method of the embodiments of the present invention is based on the parametric input of parameters such as external loads, cross-sectional dimensions, steel bar arrangements, and material types. Based on the basic principle of the allowable stress method, an eccentric tensile formula applicable to circular cross-sections is derived. After distinguishing the type of small or large eccentric tension, the steel bar stress, concrete stress, and crack width are calculated according to the relevant specifications of the railway industry. This method is relatively simple to operate and easy to master, suitable for batch operation and program development, providing strong technical support for bridges in the railway and rail transit industries.

[0130] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for checking eccentric tension of circular cross-section based on allowable stress method, characterized in that: The specific steps include: S100: Establish a material database to define the physical properties and mechanical characteristics of concrete and steel engineering materials, and allow users to customize the allowable stress values ​​of materials; S200: Input the parameters required for project calculation in the parameter input interface; S300: Based on the material database defined in step S100 and the parameters input in step S200, material parameter indexing, section parameter compilation and large and small eccentric tension types are automatically performed, and the corresponding large and small eccentric tension calculation models are selected according to the judgment results to perform small eccentric tension verification and large eccentric tension verification.

2. The eccentric tension calculation method for circular cross-section based on the allowable stress method according to claim 1 is characterized in that: The parameters in step S200 include load combination type, component size, material type, reinforcement data and combined internal force.

3. The eccentric tension calculation method for circular cross-section based on the allowable stress method according to claim 1 is characterized in that: The small eccentric tension calculation in step S300 includes calculating the maximum reinforcement stress on the tension side of the cross section. The specific calculation process is as follows: Calculate the moment of inertia of the steel bar Is: Among them, As is the steel bar area, r g It is the distance from the center of the member to the center of gravity of the reinforcement; The maximum tensile stress of the steel bar is: s s =N / A s +My / (I s )≤[σ s ] (2) Where N is the calculated axial tension, M is the calculated bending moment, As is the steel area, Is is the moment of inertia of the steel section, and y is the distance from the center of the section to the center of the outermost row of steel bars.

4. The eccentric tension calculation method for circular cross-section based on the allowable stress method according to claim 1 is characterized in that: The large eccentric tension calculation in step S300 includes determining the compression angle, the maximum stress of concrete in the compression zone, and the calculation of the stress of steel bars in the compression zone.

5. The eccentric tension calculation method for circular cross-section based on the allowable stress method according to claim 4, characterized in that: The compression angle α is calculated as follows: The position of the center axis of the circular section is related to the axial force F, the eccentric distance e, the radius R and the reinforcement ratio. Its position can be determined by the following equation: ∑∫σdA=F (3) ∑∫σρdA=M=Fe (4) Among them, σ is the stress function; dA is the area element; ρ is the distance from dA to the centroid; ∫ is the integral sign, and its scope of action, for concrete only the compression area is considered, for steel bars the entire area is considered, and we get: V=2sin 3 α-3αcosα+3sinαcos 2 a (6) W=12α-3sin4α-32sin 3 αcosα (7) Q=3πcosα (8) Where, e is the eccentricity for calculating the axial tension F; M is the calculated bending moment, calculated as F·e; R is the radius of the member section; r g is the distance from the center of gravity of the steel bar to the center of the section; n is the ratio of the elastic modulus of the steel bar to the compressive elastic modulus of the concrete; K is the coefficient μ is the reinforcement ratio μ=A g / πR 2 ; α is half of the central angle of the circle opposite to the compression zone; W, V, and Q are all functions of the central angle α; By initially assigning the value of angle α to the program, equations (6) to (8) can all be calculated based on the assigned angle α. By setting the error of equation (5) to be equal to 10 5 , the iteration step of angle α is 0.0001 degrees. The program iterates cyclically according to the initial assignment and the iteration step to make both sides of the equation (5) equal. At this time, α is the semi-central angle α of the actual stress condition. The position of the central axis is determined based on it, and the length of the compression zone is 2KR.

6. The eccentric tension calculation method for circular cross-section based on the allowable stress method according to claim 5 is characterized in that: Calculate the maximum stress of concrete and steel stress in the compression zone based on the compression angle α: According to equations (3) and (4), the maximum stress of concrete in the compression zone is obtained as follows: According to formula (9), the stress of steel bars in the compression zone is obtained as:

7. A method for checking eccentric tension of a circular section based on the allowable stress method according to any one of claims 1 to 6, characterized in that: Also includes: Calculate crack width according to project requirements.

8. A data processing device for eccentric tension calculation of circular cross section based on allowable stress method, used to implement the eccentric tension calculation method of circular cross section based on allowable stress method as claimed in any one of claims 1 to 7, characterized in that: include: Material database module, used to establish and maintain the properties of engineering materials, and provide retrieval and update functions of material parameters; Parameter entry module, used to input various parameters required for project calculation and perform verification; The calculation and analysis module is used to index material parameters, compile section parameters, identify large and small eccentricities, and perform corresponding tensile calculations. It can also calculate crack widths as needed. The result output module is used to output the verification and analysis results.

9. An electronic device, characterized in that: include: at least one memory for storing a computer program; At least one processor is used to implement the steps of the eccentric tension verification method of a circular section based on the allowable stress method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for verifying the eccentric tension of a circular section based on the allowable stress method as described in any one of claims 1 to 7.

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