Large-span steel box basket arch bridge arch foot stress performance analysis and optimized installation method

Abstract

The invention relates to the technical field of bridge construction, in particular to a large-span steel box basket arch bridge arch foot stress performance analysis and optimal installation method, which comprises the following steps of: investigating a project background and a research status; establishing and analyzing a full-bridge finite element model; establishing a local model of the steel box concrete arch springing; carrying out local stress performance analysis on the arch springing; carrying out arch foot optimization design scheme planning; analysis and comparison of an optimization design scheme; formulating an optimized installation method; according to the method, the actual stress state of the bridge can be accurately simulated by establishing the finite element model of the full bridge and the local arch springing, an accurate mechanical analysis basis is provided for optimization design and construction, an optimization design scheme of the concrete filling length and partial filling is provided, the optimization effect is evaluated through stress analysis, and the technical and economic indexes of the bridge can be evaluated. The stress performance of the arch springing is effectively improved, and the overall safety of a bridge is improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge construction, and in particular to a stress performance analysis and optimized installation method of an arch foot of a large-span steel box basket arch bridge. Background Art

[0002] In order to ensure the completion quality of the bridge, the key is to reasonably control the construction quality. Therefore, bridge construction control is one of the most important links in the entire construction process. On the other hand, as the span of the bridge continues to increase, the lateral stiffness of the bridge continues to decrease, which in turn brings more bridge instability problems and becomes an important factor restricting the development of steel box arch bridges.

[0003] The long-span steel box basket arch bridge is a type of bridge structure, the main feature of which is that the arch ribs are tilted outward to form a basket shape. This structural form can effectively improve the stability and bearing capacity of the bridge. As an important part of the arch bridge, the arch foot bears huge pressure transmitted from the arch ribs. Its stress performance is directly related to the safety and durability of the entire bridge. In the long-span steel box basket arch bridge, the stress condition of the arch foot is complex. It not only bears vertical pressure, but also bears various loads such as bending moment and shear force. Therefore, in-depth analysis of the stress performance of the arch foot and improving its stress state through optimized design are of great significance to ensure the overall safety of the bridge and improve economic benefits.

[0004] However, in general, traditional solutions lack in-depth analysis of the stress performance of the arch foot, resulting in stress concentration, structural fatigue and other problems during actual use. The possibility of optimized design has not been fully considered, resulting in the overall safety and economy of the bridge to be improved. Its construction methods and processes may be cumbersome, resulting in low construction efficiency and high costs. There is also a lack of comprehensive evaluation of the overall technical and economic indicators of the project, resulting in the economic feasibility and environmental benefits of the solution to be discussed. At the same time, its technical limitations and economic problems have restricted its promotion and application, which is not conducive to the overall improvement of the industry's technical level. In summary, it is necessary to propose an analysis of the stress performance of the arch foot of a large-span steel box basket arch bridge and an optimized installation method to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing its installation, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: The stress performance analysis and optimized installation method of the arch foot of the large-span steel box basket arch bridge include the following steps: S1. Research on project background and research status; S2. Establishment and analysis of the full bridge finite element model; S3. Establishment of local model of steel box concrete arch foot; S4. Carry out local stress performance analysis of arch foot; S5. Plan the optimal design of the arch foot; S6. Analysis and comparison of optimized design solutions; S7. Develop optimized installation methods; S8. Conduct technical and economic indicator evaluation.

[0007] Preferably, the implementation process of step S1 is as follows: S1.1. Research on the development of steel box arch bridges at home and abroad: S1.1.1. Literature search: Academic databases including CNKI, IEEEXplore, and ScienceDirect were used, with the search keywords “steel box arch bridge,” “basket arch bridge,” “steel box bridge design,” “construction technology,” and “operation and maintenance”; S1.1.2. Literature classification: Classify the retrieved literature into three aspects: design, construction, and operation and maintenance, and classify and summarize them according to the publication time and relevance of the research content; S1.1.3. Data collation: Use EndNote or Zotero document management tools to collate the collected literature, form a reference list, and indicate the main research content and conclusions of each document; S1.1.4. Current situation analysis: Use table tools to compare and analyze the development status of steel box arch bridges at home and abroad, focusing on the application status and technical development trend of basket arch bridges; S1.1.5. Form a research report: Write a research report on the development of steel box basket arch bridges at home and abroad, summarizing the characteristics, hot spots and existing problems of current research; S1.2. Summarize the structural characteristics of steel box basket arch bridge: S1.2.1. Structural form analysis: Through literature research, determine the main structural characteristics of the steel box basket arch bridge, including structural type, construction method, material properties, and form a preliminary overview of the structural characteristics; S1.2.2. Summarize the design methods: Summarize the existing design methods of CFST arch footings and CFST arch footings, analyze their respective advantages and disadvantages, and form a comparison table of design methods; S1.2.3. Research on the current status of optimization design research: Search for literature related to optimization design, focusing on collecting optimization design strategies and application cases of steel tube concrete arch footings and steel box concrete arch footings; S1.2.4. Summary of research status: Based on the research content, summarize the current status of research on optimization design of steel box basket arch bridges, identify the deficiencies in the research and the direction of improvement; S1.2.5. Necessity and innovation of the research: Based on the above analysis, the necessity of this study is proposed, and possible innovations are identified, including the application of new materials and the exploration of new design methods.

[0008] Preferably, the implementation process of step S2 is as follows: S2.1. Use MIDAS / CIVIL software to establish the full bridge finite element model: S2.1.1. Model selection and parameter definition: Select the beam element BEAM, truss element TRUSS, and plate element PLATE in the MIDAS / CIVIL software, and set the corresponding material properties and section parameters; S2.1.2. Arch rib modeling: Use beam elements to simulate the arch rib structure, input node coordinates according to the actual bridge geometry, and generate arch rib elements; S2.1.3. Modeling of cross braces and beams: Use beam elements to define the geometry and material properties of cross braces and beams, and establish a structural model connected to the arch ribs; S2.1.4. Hanger modeling: Use truss units to simulate the hanger, input the hanger length and stiffness parameters, and set the connection nodes with the arch rib and main beam; S2.1.5. Bridge deck modeling: Establish a concrete bridge deck model using plate elements, input the plate thickness, elastic modulus and Poisson's ratio, and form a bridge deck mesh; S2.2. Load-carrying capacity and limit state analysis of the full bridge model S2.2.1. Load definition: define various load types in MIDAS / CIVIL, including dead load DEADLOAD, live load LIVELOAD, temperature load TEMPERATURELOAD, wind load WINDLOAD, and set load combinations; S2.2.2. Boundary condition setting: Set the support boundary conditions of the full bridge model, including fixed supports and sliding supports, to ensure the stability of the model; S2.2.3. Solution settings: Select the analysis type as linear static analysis LINEARSTATICANALYSIS and nonlinear analysis NONLINEARANALYSIS, and set the analysis accuracy and iteration convergence standard; S2.2.4. Internal force and stress calculation: Run the MIDAS / CIVIL solver to calculate the internal force, stress and deformation of the entire bridge under various load combinations, and extract the stress results of key parts; S2.2.5. Safety verification: Based on the calculation results, safety verification of the ultimate limit state of bearing capacity and the ultimate limit state of normal use is carried out to ensure the safety of the bridge during the operation stage.

[0009] Preferably, the implementation process of step S3 is as follows: S3.1. Use MIDAS / FEA software to establish the local finite element model of the arch foot: S3.1.1. Software preparation and initial settings: Start the MIDAS / FEA software and select the three-dimensional solid element SOLIDELEMENT to model the arch foot local model; S3.1.2. Geometric modeling: Based on the actual geometric dimensions of the arch foot, input relevant parameters to create a three-dimensional geometric model of the arch foot to ensure that the model is consistent with the actual structural dimensions; S3.1.3. Material property definition: Define the material properties of steel and concrete in MIDAS / FEA, including elastic modulus, Poisson's ratio, density, and plasticity parameters; S3.1.4. Meshing: Use eight-node hexahedral elements HEXA8ELEMENT to mesh the geometric model and ensure that the mesh density is moderate to ensure calculation accuracy and efficiency; S3.1.5. Boundary conditions and loading settings: Set fixed boundary conditions and load application points in the local model to provide conditions for subsequent analysis; S3.2. Extract the most unfavorable boundary load and apply it to the local model of the arch foot: S3.2.1. Select the most unfavorable load condition: extract the internal force and stress data of the arch foot area from the finite element analysis results of the whole bridge, and select the three most unfavorable load combinations; S3.2.2. Data conversion and import: Convert the selected load case data into a format recognizable by MIDAS / FEA, including text files or Excel tables, and import them into the local model; S3.2.3. Apply loads: In MIDAS / FEA, apply the three most unfavorable load conditions to the corresponding positions of the local model of the arch foot one by one according to the imported data; S3.2.4. Verify the correctness of load application: Check whether the load application position and size are consistent with the analysis results of the full bridge model to ensure that the load application of the local model is accurate; S3.2.5. Store analysis model: Save the loaded local finite element model to prepare for subsequent stress performance analysis.

[0010] Preferably, the implementation process of step S4 is as follows: S4.1. Force analysis of local model of arch foot: S4.1.1. Set the analysis type: Select the appropriate analysis type in MIDAS / FEA, including static analysis STATICANALYSIS or nonlinear analysis NONLINEARANALYSIS, to prepare for calculating the stress distribution of the arch foot; S4.1.2. Solver parameter adjustment: set the solver's calculation accuracy, convergence criteria and maximum number of iterations to ensure the accuracy and reliability of the calculation results; S4.1.3. Run stress analysis: Start the stress analysis calculation. MIDAS / FEA will calculate the stress and strain of the arch foot under various load conditions according to the set loads and boundary conditions; S4.1.4. Result extraction and processing: Extract stress data of each component of the arch foot, including maximum principal stress, VonMises stress, and shear stress, and perform preliminary processing and analysis on the data; S4.1.5. Generate stress distribution diagram: Use the post-processing function of MIDAS / FEA to generate the stress distribution diagram of the local model of the arch foot, which provides a basis for further evaluating the stress performance of the arch foot; S4.2. Evaluation of the stress performance of the arch foot: S4.2.1. Data analysis and comparison: Compare the stress data of each component of the arch foot under the three most unfavorable load conditions to identify stress concentration points and possible structural weaknesses; S4.2.2. Reasonableness judgment: According to the bridge design specifications and structural engineering theory, evaluate the stress performance of the arch foot under various load conditions and judge the rationality of its design; S4.2.3. Analysis of concrete filling effect: Compare the stress distribution of the arch foot under different filling conditions and analyze the improvement effect of filling concrete on the stress performance of the arch foot; S4.2.4. Strength check of key components: Based on the results of the force analysis, the strength of the key components of the arch foot shall be checked to ensure that they meet the design requirements; S4.2.5. Write an analysis report: Summarize the analysis results and write an analysis report on the local stress performance of the arch foot to provide a reference for subsequent optimization design.

[0011] Preferably, the implementation process of step S5 is as follows: S5.1. Propose an optimal design scheme for concrete filling length: S5.1.1. Optimization scheme conception: Based on the above local stress performance analysis results, determine the key factors affecting the stress of the arch foot, including the stress concentration location and the maximum stress area; based on these factors, preliminarily propose two different optimization schemes for concrete filling length; S5.1.2. Concrete filling length design: Design the concrete filling lengths of the arch foot in MIDAS / FEA with different lengths, taking into account the stress distribution inside and outside the filling area and the structural stability, to form an optimized design model; S5.1.3. Material property setting: In each optimization scheme, redefine the material properties of the concrete filling area, including elastic modulus and strength parameters, to ensure that the model reflects the actual mechanical properties after filling; S5.1.4. Boundary conditions and load application: Keep the same boundary conditions and load application method as the original design scheme, and apply the most unfavorable load condition mentioned above to the new optimized design model; S5.1.5. Preliminary calculation and analysis: Run the stress analysis of MIDAS / FEA to calculate the stress distribution of the arch foot under the two concrete filling length schemes, generate stress diagrams and deformation diagrams, and preliminarily evaluate the optimization effect; S5.2. Propose an optimized design for partial filling S5.2.1. Identification of optimization areas: Analyze the stress distribution diagram of the arch foot mentioned above, identify the areas where the stress may be significantly improved in the case of partial filling, and determine the concrete filling areas that need to be optimized; S5.2.2. Partial filling design: Propose two partial filling schemes, define the specific location and range of different filling areas, consider the overall impact of the filling on the structural stress, and generate an optimized model; S5.2.3. Filling method and material configuration: For each partial filling area, set the specific filling method and material configuration to ensure the feasibility and constructibility of the plan; S5.2.4. Model verification and adjustment: Perform model verification on some filling optimization schemes, adjust boundary conditions and material properties, and ensure that the model can truly reflect the optimized structural performance; S5.2.5. Calculation and comparative analysis: Use MIDAS / FEA to perform stress analysis on the partial filling scheme, calculate the stress distribution of the arch foot under each scheme, and compare it with the full filling scheme to evaluate the advantages of the partial filling scheme.

[0012] Preferably, the implementation process of step S6 is as follows: S6.1. Perform stress analysis on the optimized design solution: S6.1.1. Model import and adjustment: Import the two concrete filling lengths and two partial filling optimization design schemes proposed above into MIDAS / FEA respectively to ensure that the boundary conditions and loading methods of all models are consistent; S6.1.2. Analysis type selection: Select NONLINEARSTATICANALYSIS to capture the actual load behavior of the arch foot under different optimization schemes; S6.1.3. Solution setting and execution: Set the solver accuracy, number of iterations and convergence criteria, perform the force analysis of the optimization scheme, and calculate the stress distribution and deformation of the arch foot under each scheme; S6.1.4. Stress result extraction: Extract stress data under each optimization scheme, including maximum stress, shear stress, and principal stress, with special attention paid to the changes in stress concentration areas after optimization; S6.1.5. Generation of deformation and stress distribution diagrams: Use the post-processing function of MIDAS / FEA to generate deformation diagrams and stress distribution diagrams for each optimized design scheme, and intuitively display the structural stress characteristics under different schemes; S6.2. Comparative evaluation of the optimized design and the original design S6.2.1. Review of original design analysis results: Review the stress analysis results of the original design again to ensure a consistent benchmark with the optimized solution; S6.2.2. Stress comparison analysis: Compare the stress data of each optimized design scheme with the original design scheme, analyze the changes in the maximum stress and stress concentration area, and evaluate the effect of each scheme in reducing stress concentration and improving structural performance; S6.2.3. Structural safety assessment: Based on the stress results of each scheme, strength and stability verification shall be conducted to determine the degree of improvement in safety of the optimized scheme; S6.2.4. Comprehensive performance comparison: Consider the stress distribution, deformation, and construction feasibility factors of each scheme, and comprehensively evaluate the superiority of each optimization scheme, especially the rationality and economy of the filling length and partial filling method; S6.2.5. Selection of the best solution: Based on the comprehensive performance evaluation results, select the optimal concrete filling length and partial filling method to provide a basis for the final design.

[0013] Preferably, the implementation process of step S7 is as follows: S7.1. Optimized installation method for steel box concrete arch footing: S7.1.1. Construction condition analysis: Based on the actual construction conditions of the bridge, analyze the factors that may affect the concrete filling of the arch foot, including the on-site construction environment, equipment limitations, and construction period requirements; S7.1.2. Installation sequence design: According to the optimized design plan, formulate the specific sequence of arch foot installation, clarify the sequence of concrete filling and the construction rhythm to ensure the structural safety during the construction process; S7.1.3. Determination of filling process: Determine the specific process of concrete filling, including pouring method, maintenance measures, and quality control points, to ensure the operability and reliability of the filling process; S7.1.4. Quality control measures: Develop a quality control plan for concrete filling and set the parameters and indicators that need to be monitored during the construction process, including concrete strength and arch foot deformation, to ensure construction quality; S7.1.5. Preparation of construction method manual: Combined with the optimized design and installation methods, a detailed construction method manual is prepared, including operation steps, precautions, and quality control points, to provide guidance for the construction team; S7.2. Implement optimized installation methods.

[0014] Preferably, the implementation process of step S7.2 is as follows: S7.2.1. Flowchart drawing: Draw a flow chart for optimizing the installation of the steel box concrete arch foot, visually showing the sequence and key points of each construction step; S7.2.2. Operational details: Describe in detail in the manual the operational details of each construction step, including mixing, transportation, pouring, vibrating, and curing of concrete; S7.2.3. Selection of construction tools and equipment: List the required construction tools and equipment, clearly identify the tools and equipment used in each construction step, and their configuration requirements; S7.2.4. Construction node monitoring: Set monitoring measures for key construction nodes, including deformation monitoring after the arch foot concrete pouring is completed and actual measurement of concrete strength, to ensure the safety and quality of the construction process; S7.2.5. Construction training and drills: Before formal construction, the construction team shall be trained and trained on the operating procedures to ensure that all construction personnel are familiar with the optimized installation methods and operating procedures.

[0015] Preferably, the implementation process of step S8 is as follows: S8.1. Technical and economic evaluation of optimized design solutions and installation methods; S8.1.1. Construction efficiency evaluation: Analyze the impact of optimized design solutions and installation methods on construction efficiency, including shortening construction time and simplifying the construction process, and quantify the improvement in construction efficiency; S8.1.2. Project cost analysis: Calculate the construction cost based on the material consumption of the optimized design and the complexity of the construction process, compare the cost difference between the optimized solution and the original design, and evaluate the economic benefits; S8.1.3. Environmental benefit assessment: Analyze the contribution of the optimization scheme to material conservation and carbon emission reduction during construction, and conduct quantitative assessment based on environmental indicators; S8.1.4. Comprehensive technical and economic analysis: Conduct a comprehensive analysis of construction efficiency, project cost, and environmental benefit indicators, calculate the overall technical and economic indicators of the optimization plan, and evaluate the feasibility of its promotion and application; S8.1.5. Write an evaluation report: Summarize the evaluation results of technical and economic indicators and write a detailed technical and economic analysis report to provide a basis for subsequent project decision-making; S8.2. Promotion and application; S8.2.1. Application scenario analysis: Analyze the applicability of the optimized design solution and installation method in other steel box basket arch bridge projects and identify engineering projects with similar structural characteristics; S8.2.2. Development of promotion and application strategies: Development of application strategies for promotion of optimized design solutions, including technical publicity, demonstration project construction, and technical training measures, to promote the widespread application of the solutions; S8.2.3. Preparation of complete technical reports: Based on the research results, prepare a complete technical report and construction instruction manual, including design points, construction process, quality control content, to provide reference for similar projects; S8.2.4. Policy and Standard Recommendations: Based on the research results, propose standardized recommendations for optimizing design solutions and installation methods, and promote their inclusion in relevant design specifications and construction standards.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: by establishing finite element models of the entire bridge and the arch foot, the present invention can accurately simulate the actual stress state of the bridge, provide an accurate mechanical analysis basis for optimal design and construction, propose an optimal design scheme for concrete filling length and partial filling, evaluate the optimization effect through force analysis, effectively improve the stress performance of the arch foot, improve the overall safety of the bridge, formulate a detailed optimized installation method, including construction sequence, filling process and quality control measures, improve construction efficiency, reduce construction costs, conduct technical and economic indicator evaluation of the optimized design scheme and installation method, ensure the economic feasibility and environmental benefits of the scheme, provide a basis for project decision-making, analyze the applicability of the optimized scheme in other projects, formulate a promotion and application strategy, and promote technological progress in the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of the stress performance analysis and optimized installation method of the arch foot of the large-span steel box basket arch bridge. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0019] See also Figure 1 The present invention proposes a method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing its installation, which specifically includes the following steps: S1. Project background and research status survey: S1.1. Research on the development of steel box arch bridges at home and abroad: S1.1.1. Literature search: Academic databases including CNKI, IEEEXplore, and ScienceDirect were used, with the search keywords “steel box arch bridge,” “basket arch bridge,” “steel box bridge design,” “construction technology,” and “operation and maintenance”; S1.1.2. Literature classification: Classify the retrieved literature into three aspects: design, construction, and operation and maintenance, and classify and summarize them according to the publication time and relevance of the research content; S1.1.3. Data collation: Use EndNote or Zotero document management tools to collate the collected literature, form a reference list, and indicate the main research content and conclusions of each document; S1.1.4. Current situation analysis: Use table tools to compare and analyze the development status of steel box arch bridges at home and abroad, focusing on the application status and technical development trend of basket arch bridges; S1.1.5. Form a research report: Write a research report on the development of steel box basket arch bridges at home and abroad, summarizing the characteristics, hot spots and existing problems of current research; S1.2. Summarize the structural characteristics of steel box basket arch bridge: S1.2.1. Structural form analysis: Through literature research, determine the main structural characteristics of the steel box basket arch bridge, including structural type, construction method, material properties, and form a preliminary overview of the structural characteristics; S1.2.2. Summarize the design methods: Summarize the existing design methods of CFST arch footings and CFST arch footings, analyze their respective advantages and disadvantages, and form a comparison table of design methods; S1.2.3. Research on the current status of optimization design research: Search for literature related to optimization design, focusing on collecting optimization design strategies and application cases of steel tube concrete arch footings and steel box concrete arch footings; S1.2.4. Summary of research status: Based on the research content, summarize the current status of research on optimization design of steel box basket arch bridges, identify the deficiencies in the research and the direction of improvement; S1.2.5. Research necessity and innovation: Based on the above analysis, propose the necessity of this study and identify possible innovations, including the application of new materials and the exploration of new design methods; S2. Establishment and analysis of the full bridge finite element model: S2.1. Use MIDAS / CIVIL software to establish the full bridge finite element model: S2.1.1. Model selection and parameter definition: Select the beam element BEAM, truss element TRUSS, and plate element PLATE in the MIDAS / CIVIL software, and set the corresponding material properties and section parameters; S2.1.2. Arch rib modeling: Use beam elements to simulate the arch rib structure, input node coordinates according to the actual bridge geometry, and generate arch rib elements; S2.1.3. Modeling of cross braces and beams: Use beam elements to define the geometry and material properties of cross braces and beams, and establish a structural model connected to the arch ribs; S2.1.4. Hanger modeling: Use truss units to simulate the hanger, input the hanger length and stiffness parameters, and set the connection nodes with the arch rib and main beam; S2.1.5. Bridge deck modeling: Establish a concrete bridge deck model using plate elements, input the plate thickness, elastic modulus and Poisson's ratio, and form a bridge deck mesh; S2.2. Load-carrying capacity and limit state analysis of the full bridge model S2.2.1. Load definition: define various load types in MIDAS / CIVIL, including dead load DEADLOAD, live load LIVELOAD, temperature load TEMPERATURELOAD, wind load WINDLOAD, and set load combinations; S2.2.2. Boundary condition setting: Set the support boundary conditions of the full bridge model, including fixed supports and sliding supports, to ensure the stability of the model; S2.2.3. Solution settings: Select the analysis type as linear static analysis LINEARSTATICANALYSIS and nonlinear analysis NONLINEARANALYSIS, and set the analysis accuracy and iteration convergence standard; S2.2.4. Internal force and stress calculation: Run the MIDAS / CIVIL solver to calculate the internal force, stress and deformation of the entire bridge under various load combinations, and extract the stress results of key parts; S2.2.5. Safety verification: Based on the calculation results, safety verification of the ultimate bearing capacity state and the normal use limit state shall be carried out to ensure the safety of the bridge during the operation stage; S3. Establishment of local model of steel box concrete arch foot: S3.1. Use MIDAS / FEA software to establish the local finite element model of the arch foot: S3.1.1. Software preparation and initial settings: Start the MIDAS / FEA software and select the three-dimensional solid element SOLIDELEMENT to model the arch foot local model; S3.1.2. Geometric modeling: Based on the actual geometric dimensions of the arch foot, input relevant parameters to create a three-dimensional geometric model of the arch foot to ensure that the model is consistent with the actual structural dimensions; S3.1.3. Material property definition: Define the material properties of steel and concrete in MIDAS / FEA, including elastic modulus, Poisson's ratio, density, and plasticity parameters; S3.1.4. Meshing: Use eight-node hexahedral elements HEXA8ELEMENT to mesh the geometric model and ensure that the mesh density is moderate to ensure calculation accuracy and efficiency; S3.1.5. Boundary conditions and loading settings: Set fixed boundary conditions and load application points in the local model to provide conditions for subsequent analysis; S3.2. Extract the most unfavorable boundary load and apply it to the local model of the arch foot: S3.2.1. Select the most unfavorable load condition: extract the internal force and stress data of the arch foot area from the finite element analysis results of the whole bridge, and select the three most unfavorable load combinations; S3.2.2. Data conversion and import: Convert the selected load case data into a format recognizable by MIDAS / FEA, including text files or Excel tables, and import them into the local model; S3.2.3. Apply loads: In MIDAS / FEA, apply the three most unfavorable load conditions to the corresponding positions of the local model of the arch foot one by one according to the imported data; S3.2.4. Verify the correctness of load application: Check whether the load application position and size are consistent with the analysis results of the full bridge model to ensure that the load application of the local model is accurate; S3.2.5. Store analysis model: save the loaded local finite element model to prepare for the subsequent force performance analysis; S4. Carry out local stress performance analysis of arch foot: S4.1. Force analysis of local model of arch foot: S4.1.1. Set the analysis type: Select the appropriate analysis type in MIDAS / FEA, including static analysis STATICANALYSIS or nonlinear analysis NONLINEARANALYSIS, to prepare for calculating the stress distribution of the arch foot; S4.1.2. Solver parameter adjustment: set the solver's calculation accuracy, convergence criteria and maximum number of iterations to ensure the accuracy and reliability of the calculation results; S4.1.3. Run stress analysis: Start the stress analysis calculation. MIDAS / FEA will calculate the stress and strain of the arch foot under various load conditions according to the set loads and boundary conditions; S4.1.4. Result extraction and processing: Extract stress data of each component of the arch foot, including maximum principal stress, VonMises stress, and shear stress, and perform preliminary processing and analysis on the data; S4.1.5. Generate stress distribution diagram: Use the post-processing function of MIDAS / FEA to generate the stress distribution diagram of the local model of the arch foot, which provides a basis for further evaluating the stress performance of the arch foot; S4.2. Evaluation of the stress performance of the arch foot: S4.2.1. Data analysis and comparison: Compare the stress data of each component of the arch foot under the three most unfavorable load conditions to identify stress concentration points and possible structural weaknesses; S4.2.2. Reasonableness judgment: According to the bridge design specifications and structural engineering theory, evaluate the stress performance of the arch foot under various load conditions and judge the rationality of its design; S4.2.3. Analysis of concrete filling effect: Compare the stress distribution of the arch foot under different filling conditions and analyze the improvement effect of filling concrete on the stress performance of the arch foot; S4.2.4. Strength check of key components: Based on the results of the force analysis, the strength of the key components of the arch foot shall be checked to ensure that they meet the design requirements; S4.2.5. Write an analysis report: Summarize the analysis results and write an analysis report on the local stress performance of the arch foot to provide a reference for subsequent optimization design; S5. Plan the optimal design of the arch foot: S5.1. Propose an optimal design scheme for concrete filling length: S5.1.1. Optimization scheme conception: Based on the above local stress performance analysis results, determine the key factors affecting the stress of the arch foot, including the stress concentration location and the maximum stress area; based on these factors, preliminarily propose two different optimization schemes for concrete filling length; S5.1.2. Concrete filling length design: Design the concrete filling lengths of the arch foot in MIDAS / FEA with different lengths, taking into account the stress distribution inside and outside the filling area and the structural stability, to form an optimized design model; S5.1.3. Material property setting: In each optimization scheme, redefine the material properties of the concrete filling area, including elastic modulus and strength parameters, to ensure that the model reflects the actual mechanical properties after filling; S5.1.4. Boundary conditions and load application: Keep the same boundary conditions and load application method as the original design scheme, and apply the most unfavorable load condition mentioned above to the new optimized design model; S5.1.5. Preliminary calculation and analysis: Run the stress analysis of MIDAS / FEA to calculate the stress distribution of the arch foot under the two concrete filling length schemes, generate stress diagrams and deformation diagrams, and preliminarily evaluate the optimization effect; S5.2. Propose an optimal design for partial filling: S5.2.1. Identification of optimization areas: Analyze the stress distribution diagram of the arch foot mentioned above, identify the areas where the stress may be significantly improved in the case of partial filling, and determine the concrete filling areas that need to be optimized; S5.2.2. Partial filling design: Propose two partial filling schemes, define the specific location and range of different filling areas, consider the overall impact of the filling on the structural stress, and generate an optimized model; S5.2.3. Filling method and material configuration: For each partial filling area, set the specific filling method and material configuration to ensure the feasibility and constructibility of the plan; S5.2.4. Model verification and adjustment: Perform model verification on some filling optimization schemes, adjust boundary conditions and material properties, and ensure that the model can truly reflect the optimized structural performance; S5.2.5. Calculation and comparative analysis: Use MIDAS / FEA to perform stress analysis on the partial filling scheme, calculate the stress distribution of the arch foot under each scheme, and compare it with the full filling scheme to evaluate the advantages of the partial filling scheme; S6. Analysis and comparison of optimized design solutions: S6.1. Perform stress analysis on the optimized design solution: S6.1.1. Model import and adjustment: Import the two concrete filling lengths and two partial filling optimization design schemes proposed above into MIDAS / FEA respectively to ensure that the boundary conditions and loading methods of all models are consistent; S6.1.2. Analysis type selection: Select NONLINEARSTATICANALYSIS to capture the actual load behavior of the arch foot under different optimization schemes; S6.1.3. Solution setting and execution: Set the solver accuracy, number of iterations and convergence criteria, perform the force analysis of the optimization scheme, and calculate the stress distribution and deformation of the arch foot under each scheme; S6.1.4. Stress result extraction: Extract stress data under each optimization scheme, including maximum stress, shear stress, and principal stress, with special attention paid to the changes in stress concentration areas after optimization; S6.1.5. Generation of deformation and stress distribution diagrams: Use the post-processing function of MIDAS / FEA to generate deformation diagrams and stress distribution diagrams for each optimized design scheme, and intuitively display the structural stress characteristics under different schemes; S6.2. Comparative evaluation of the optimized design and the original design S6.2.1. Review of original design analysis results: Review the stress analysis results of the original design again to ensure a consistent benchmark with the optimized solution; S6.2.2. Stress comparison analysis: Compare the stress data of each optimized design scheme with the original design scheme, analyze the changes in the maximum stress and stress concentration area, and evaluate the effect of each scheme in reducing stress concentration and improving structural performance; S6.2.3. Structural safety assessment: Based on the stress results of each scheme, strength and stability verification shall be conducted to determine the degree of improvement in safety of the optimized scheme; S6.2.4. Comprehensive performance comparison: Consider the stress distribution, deformation, and construction feasibility factors of each scheme, and comprehensively evaluate the superiority of each optimization scheme, especially the rationality and economy of the filling length and partial filling method; S6.2.5. Best solution selection: Based on the comprehensive performance evaluation results, select the best concrete filling length and partial filling method to provide a basis for the final design; S7. Develop optimized installation methods: S7.1. Optimized installation method for steel box concrete arch footing: S7.1.1. Construction condition analysis: Based on the actual construction conditions of the bridge, analyze the factors that may affect the concrete filling of the arch foot, including the on-site construction environment, equipment limitations, and construction period requirements; S7.1.2. Installation sequence design: According to the optimized design plan, formulate the specific sequence of arch foot installation, clarify the sequence of concrete filling and the construction rhythm to ensure the structural safety during the construction process; S7.1.3. Determination of filling process: Determine the specific process of concrete filling, including pouring method, maintenance measures, and quality control points, to ensure the operability and reliability of the filling process; S7.1.4. Quality control measures: Develop a quality control plan for concrete filling and set the parameters and indicators that need to be monitored during the construction process, including concrete strength and arch foot deformation, to ensure construction quality; S7.1.5. Preparation of construction method manual: Combined with the optimized design and installation methods, a detailed construction method manual is prepared, including operation steps, precautions, and quality control points, to provide guidance for the construction team; S7.2. Implement optimized installation methods.

[0020] Preferably, the implementation process of step S7.2 is as follows: S7.2.1. Flowchart drawing: Draw a flow chart for optimizing the installation of the steel box concrete arch foot, visually showing the sequence and key points of each construction step; S7.2.2. Operational details: Describe in detail in the manual the operational details of each construction step, including mixing, transportation, pouring, vibrating, and curing of concrete; S7.2.3. Selection of construction tools and equipment: List the required construction tools and equipment, clearly identify the tools and equipment used in each construction step, and their configuration requirements; S7.2.4. Construction node monitoring: Set monitoring measures for key construction nodes, including deformation monitoring after the arch foot concrete pouring is completed and actual measurement of concrete strength, to ensure the safety and quality of the construction process; S7.2.5. Construction training and drills: Before the formal construction, the construction team shall be trained and drilled on the operation procedures to ensure that all construction personnel are familiar with the optimized installation methods and operation procedures; S8. Conduct technical and economic indicator evaluation: S8.1. Technical and economic evaluation of optimized design solutions and installation methods; S8.1.1. Construction efficiency evaluation: Analyze the impact of optimized design solutions and installation methods on construction efficiency, including shortening construction time and simplifying the construction process, and quantify the improvement in construction efficiency; S8.1.2. Project cost analysis: Calculate the construction cost based on the material consumption of the optimized design and the complexity of the construction process, compare the cost difference between the optimized solution and the original design, and evaluate the economic benefits; S8.1.3. Environmental benefit assessment: Analyze the contribution of the optimization scheme to material conservation and carbon emission reduction during construction, and conduct quantitative assessment based on environmental indicators; S8.1.4. Comprehensive technical and economic analysis: Conduct a comprehensive analysis of construction efficiency, project cost, and environmental benefit indicators, calculate the overall technical and economic indicators of the optimization plan, and evaluate the feasibility of its promotion and application; S8.1.5. Write an evaluation report: Summarize the evaluation results of technical and economic indicators and write a detailed technical and economic analysis report to provide a basis for subsequent project decision-making; S8.2. Promotion and application; S8.2.1. Application scenario analysis: Analyze the applicability of the optimized design solution and installation method in other steel box basket arch bridge projects and identify engineering projects with similar structural characteristics; S8.2.2. Development of promotion and application strategies: Development of application strategies for promotion of optimized design solutions, including technical publicity, demonstration project construction, and technical training measures, to promote the widespread application of the solutions; S8.2.3. Preparation of complete technical reports: Based on the research results, prepare a complete technical report and construction instruction manual, including design points, construction process, quality control content, to provide reference for similar projects; S8.2.4. Policy and Standard Recommendations: Based on the research results, propose standardized recommendations for optimizing design solutions and installation methods, and promote their inclusion in relevant design specifications and construction standards. Example

[0021] In the specific implementation process, the present invention takes the S235 project as the engineering background, studies the stress performance of the whole bridge in the operation stage and the local stress conditions of the steel box concrete arch foot, and optimizes the design of the arch foot. In a construction project of a complexly designed large-span steel box basket arch bridge, the stress performance of the arch foot of the bridge is crucial to the safety and durability of the entire bridge. In order to ensure the stress performance and construction efficiency of the arch foot, it is decided to use the large-span steel box basket arch bridge arch foot stress performance analysis and optimized installation method involved in the present invention for optimized design and construction. The specific application process includes the following: Project background and research status survey operation process: Investigate the development of steel box arch bridges at home and abroad, focus on analyzing the application status and technical development trend of basket handle arch bridges, summarize the structural characteristics and existing design methods of steel box basket handle arch bridges, and conduct research on the current status of optimization design research; Through this step, we can fully understand the current technical level and existing problems, provide a basis for subsequent research, identify the necessity and innovation of research, and ensure the cutting-edge and practical nature of the research direction; Establishment and analysis of the finite element model of the entire bridge: Use MIDAS / CIVIL software to establish the finite element model of the entire bridge, including arch ribs, cross braces, beams, hangers and bridge decks, to conduct load-bearing capacity and limit state analysis of the entire bridge to ensure the safety of the bridge; Through this step, the whole bridge structure is accurately simulated to provide accurate boundary conditions for the subsequent local analysis of the arch foot, ensuring that the bridge design meets the safety and durability requirements; Establishment of local model of steel box concrete arch foot: Use MIDAS / FEA software to establish the local finite element model of the arch foot, extract the most unfavorable load in the whole bridge model, and apply it to the local model of the arch foot; Through this step, the stress performance of the arch foot is accurately analyzed, the stress concentration points are identified, and an accurate mechanical analysis basis is provided for optimal design; Conduct local stress performance analysis of the arch foot: Conduct stress analysis on the local model of the arch foot, including static analysis and nonlinear analysis, evaluate the stress performance of the arch foot, and conduct concrete filling effect analysis; Through this step, we can fully understand the stress performance of the arch foot under different load conditions and determine the role of concrete filling in improving the stress performance of the arch foot; Plan the optimal design of the arch foot: propose the optimal design of the concrete filling length and partial filling, conduct stress analysis on each scheme, and evaluate the optimization effect; Through this step, the stress performance of the arch foot is improved by optimizing the design, the overall safety of the bridge is improved, the construction difficulty and cost are reduced, and the economic benefits are improved; Analysis and comparison of optimized design solutions: Conduct stress analysis on each optimized design solution and compare it with the original design solution, comprehensively evaluate the superiority of each solution and select the best solution; Through this step, the effectiveness and feasibility of the optimization plan are ensured, providing a scientific basis for the final design; Formulate optimized installation methods: Analyze construction conditions, formulate the installation sequence and filling process of the arch foot, set quality control measures, and compile a construction method manual; Through this step, the safety and quality controllability of the construction process are ensured, the construction efficiency is improved, and the construction cost is reduced; At the same time, it should be noted that this step refers to the following construction standards: Technical Specifications for Highway Bridge Construction; "Concrete Structure Engineering Construction Quality Acceptance Code"; "Code for Acceptance of Construction Quality of Steel Structure Engineering"; Conduct technical and economic indicator evaluation and promotion and application: evaluate the technical and economic indicators of the optimized design scheme and installation method, analyze the applicability of the optimized scheme in other projects, and formulate promotion and application strategies; Through this step, the economic feasibility and environmental benefits of the optimization plan can be ensured, the optimization plan can be widely used in similar projects, and the overall technical level of the industry can be improved.

[0022] In summary, the present invention can accurately simulate the actual stress state of the bridge by establishing a finite element model of the entire bridge and the arch foot, provide an accurate mechanical analysis basis for optimal design and construction, propose an optimal design scheme for concrete filling length and partial filling, evaluate the optimization effect through force analysis, effectively improve the stress performance of the arch foot, improve the overall safety of the bridge, formulate a detailed optimized installation method, including construction sequence, filling process and quality control measures, improve construction efficiency, reduce construction costs, evaluate the technical and economic indicators of the optimized design scheme and installation method, ensure the economic feasibility and environmental benefits of the scheme, provide a basis for project decision-making, analyze the applicability of the optimization scheme in other projects, formulate a promotion and application strategy, and promote technological progress in the industry.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Analysis of the stress performance of the arch foot of a large-span steel box basket arch bridge and the optimized installation method, characterized in that: The following steps are involved: S1. Research on project background and research status; S2. Establishment and analysis of the full bridge finite element model; S3. Establishment of local model of steel box concrete arch foot; S4. Carry out local stress performance analysis of arch foot; S5. Plan the optimal design of the arch foot; S6. Analysis and comparison of optimized design solutions; S7. Develop optimized installation methods; S8. Conduct technical and economic indicator evaluation.

2. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 1 is characterized in that: The implementation process of step S1 is as follows: S1.

1. Research on the development of steel box arch bridges at home and abroad: S1.1.

1. Literature search: Academic databases including CNKI, IEEEXplore, and ScienceDirect were used, with the search keywords "steel box arch bridge", "basket arch bridge", "steel box bridge design", "construction technology", and "operation and maintenance"; S1.1.

2. Literature classification: Classify the retrieved literature into three aspects: design, construction, and operation and maintenance, and classify and summarize them according to the publication time and relevance of the research content; S1.1.

3. Data collation: Use EndNote or Zotero document management tools to collate the collected literature, form a reference list, and indicate the main research content and conclusions of each document; S1.1.

4. Current situation analysis: Use table tools to compare and analyze the development status of steel box arch bridges at home and abroad, focusing on the application status and technical development trend of basket arch bridges; S1.1.

5. Form a research report: Write a research report on the development of steel box basket arch bridges at home and abroad, summarizing the characteristics, hot spots and existing problems of current research; S1.

2. Summarize the structural characteristics of steel box basket arch bridge: S1.2.

1. Structural form analysis: Through literature research, determine the main structural characteristics of the steel box basket arch bridge, including structural type, construction method, material properties, and form a preliminary overview of the structural characteristics; S1.2.

2. Summarize the design methods: Summarize the existing design methods of CFST arch footings and CFST arch footings, analyze their respective advantages and disadvantages, and form a comparison table of design methods; S1.2.

3. Research on the current status of optimization design research: Search for literature related to optimization design, focusing on collecting optimization design strategies and application cases of steel tube concrete arch footings and steel box concrete arch footings; S1.2.

4. Summary of research status: Based on the research content, summarize the current status of research on optimization design of steel box basket arch bridges, identify the deficiencies in the research and the direction of improvement; S1.2.

5. Necessity and innovation of the research: Based on the above analysis, the necessity of this study is proposed, and possible innovations are identified, including the application of new materials and the exploration of new design methods.

3. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 2 is characterized in that: The implementation process of step S2 is as follows: S2.

1. Use MIDAS / CIVIL software to establish the full bridge finite element model: S2.1.

1. Model selection and parameter definition: Select beam element (BEAM), truss element (TRUSS), plate element (PLATE) in MIDAS / CIVIL software, and set the corresponding material properties and section parameters; S2.1.

2. Arch rib modeling: Use beam elements to simulate the arch rib structure, input node coordinates according to the actual bridge geometry, and generate arch rib elements; S2.1.

3. Modeling of cross braces and beams: Use beam elements to define the geometry and material properties of cross braces and beams, and establish a structural model connected to the arch ribs; S2.1.

4. Hanger modeling: Use truss units to simulate the hanger, input the hanger length and stiffness parameters, and set the connection nodes with the arch rib and main beam; S2.1.

5. Bridge deck modeling: Establish a concrete bridge deck model using plate elements, input the plate thickness, elastic modulus and Poisson's ratio, and form a bridge deck mesh; S2.

2. Load-carrying capacity and limit state analysis of the full bridge model S2.2.

1. Load definition: define various load types in MIDAS / CIVIL, including dead load (DEADLOAD), live load (LIVELOAD), temperature load (TEMPERATURELOAD), wind load (WINDLOAD), and set load combinations; S2.2.

2. Boundary condition setting: Set the support boundary conditions of the full bridge model, including fixed supports and sliding supports, to ensure the stability of the model; S2.2.

3. Solution settings: Select the analysis type as linear static analysis (LINEARSTATICANALYSIS) and nonlinear analysis (NONLINEARANALYSIS), and set the analysis accuracy and iterative convergence standard; S2.2.

4. Internal force and stress calculation: Run the MIDAS / CIVIL solver to calculate the internal force, stress and deformation of the entire bridge under various load combinations, and extract the stress results of key parts; S2.2.

5. Safety verification: Based on the calculation results, safety verification of the ultimate limit state of bearing capacity and the ultimate limit state of normal use is carried out to ensure the safety of the bridge during the operation stage.

4. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 3 is characterized in that: The implementation process of step S3 is as follows: S3.

1. Use MIDAS / FEA software to establish the local finite element model of the arch foot: S3.1.

1. Software preparation and initial settings: Start the MIDAS / FEA software and select the three-dimensional solid element (SOLIDELEMENT) to model the local model of the arch foot; S3.1.

2. Geometric modeling: Based on the actual geometric dimensions of the arch foot, input relevant parameters to create a three-dimensional geometric model of the arch foot to ensure that the model is consistent with the actual structural dimensions; S3.1.

3. Material property definition: Define the material properties of steel and concrete in MIDAS / FEA, including elastic modulus, Poisson's ratio, density, and plasticity parameters; S3.1.

4. Meshing: Use eight-node hexahedral elements (HEXA8ELEMENT) to mesh the geometric model and ensure that the mesh density is moderate to ensure calculation accuracy and efficiency; S3.1.

5. Boundary conditions and loading settings: Set fixed boundary conditions and load application points in the local model to provide conditions for subsequent analysis; S3.

2. Extract the most unfavorable boundary load and apply it to the local model of the arch foot: S3.2.

1. Select the most unfavorable load condition: extract the internal force and stress data of the arch foot area from the finite element analysis results of the whole bridge, and select the three most unfavorable load combinations; S3.2.

2. Data conversion and import: Convert the selected load case data into a format recognizable by MIDAS / FEA, including text files or Excel tables, and import them into the local model; S3.2.

3. Apply loads: In MIDAS / FEA, apply the three most unfavorable load conditions to the corresponding positions of the local model of the arch foot one by one according to the imported data; S3.2.

4. Verify the correctness of load application: Check whether the load application position and size are consistent with the analysis results of the full bridge model to ensure that the load application of the local model is accurate; S3.2.

5. Store analysis model: Save the loaded local finite element model to prepare for subsequent stress performance analysis.

5. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 4 is characterized in that: The implementation process of step S4 is as follows: S4.

1. Force analysis of local model of arch foot: S4.1.

1. Set the analysis type: Select the appropriate analysis type in MIDAS / FEA, including static analysis (STATICANALYSIS) or nonlinear analysis (NONLINEARANALYSIS), to prepare for calculating the stress distribution of the arch foot; S4.1.

2. Solver parameter adjustment: set the solver's calculation accuracy, convergence criteria and maximum number of iterations to ensure the accuracy and reliability of the calculation results; S4.1.

3. Run force analysis: Start the force analysis calculation. MIDAS / FEA will calculate the stress and strain of the arch foot under various load conditions according to the set loads and boundary conditions; S4.1.

4. Result extraction and processing: Extract stress data of each component of the arch foot, including maximum principal stress, VonMises stress, and shear stress, and perform preliminary processing and analysis on the data; S4.1.

5. Generate stress distribution diagram: Use the post-processing function of MIDAS / FEA to generate the stress distribution diagram of the local model of the arch foot, which provides a basis for further evaluating the stress performance of the arch foot; S4.

2. Evaluation of the stress performance of the arch foot: S4.2.

1. Data analysis and comparison: Compare the stress data of each component of the arch foot under the three most unfavorable load conditions to identify stress concentration points and possible structural weaknesses; S4.2.

2. Reasonableness judgment: According to the bridge design specifications and structural engineering theory, evaluate the stress performance of the arch foot under various load conditions and judge the rationality of its design; S4.2.

3. Analysis of concrete filling effect: Compare the stress distribution of the arch foot under different filling conditions and analyze the improvement effect of filling concrete on the stress performance of the arch foot; S4.2.

4. Strength check of key components: Based on the results of the force analysis, the strength of the key components of the arch foot shall be checked to ensure that they meet the design requirements; S4.2.

5. Write an analysis report: Summarize the analysis results and write an analysis report on the local stress performance of the arch foot to provide a reference for subsequent optimization design.

6. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 5 is characterized in that: The implementation process of step S5 is as follows: S5.

1. Propose an optimal design scheme for concrete filling length: S5.1.

1. Optimization scheme conception: Based on the above local stress performance analysis results, determine the key factors affecting the stress of the arch foot, including the stress concentration location and the maximum stress area; based on these factors, preliminarily propose two different optimization schemes for concrete filling length; S5.1.

2. Concrete filling length design: Design the concrete filling lengths of the arch foot in MIDAS / FEA with different lengths, taking into account the stress distribution inside and outside the filling area and the structural stability, to form an optimized design model; S5.1.

3. Material property setting: In each optimization scheme, redefine the material properties of the concrete filling area, including elastic modulus and strength parameters, to ensure that the model reflects the actual mechanical properties after filling; S5.1.

4. Boundary conditions and load application: Keep the same boundary conditions and load application method as the original design scheme, and apply the most unfavorable load condition mentioned above to the new optimized design model; S5.1.

5. Preliminary calculation and analysis: Run the stress analysis of MIDAS / FEA to calculate the stress distribution of the arch foot under the two concrete filling length schemes, generate stress diagrams and deformation diagrams, and preliminarily evaluate the optimization effect; S5.

2. Propose an optimized design for partial filling S5.2.

1. Identification of optimization areas: Analyze the stress distribution diagram of the arch foot mentioned above, identify the areas where the stress may be significantly improved in the case of partial filling, and determine the concrete filling areas that need to be optimized; S5.2.

2. Partial filling design: Propose two partial filling schemes, define the specific location and range of different filling areas, consider the overall impact of the filling on the structural stress, and generate an optimized model; S5.2.

3. Filling method and material configuration: For each partial filling area, set the specific filling method and material configuration to ensure the feasibility and constructibility of the plan; S5.2.

4. Model verification and adjustment: Perform model verification on some filling optimization schemes, adjust boundary conditions and material properties, and ensure that the model can truly reflect the optimized structural performance; S5.2.

5. Calculation and comparative analysis: Use MIDAS / FEA to perform stress analysis on the partial filling scheme, calculate the stress distribution of the arch foot under each scheme, and compare it with the full filling scheme to evaluate the advantages of the partial filling scheme.

7. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing its installation according to claim 6 is characterized in that: The implementation process of step S6 is as follows: S6.

1. Perform stress analysis on the optimized design solution: S6.1.

1. Model import and adjustment: Import the two concrete filling lengths and two partial filling optimization design schemes proposed above into MIDAS / FEA respectively to ensure that the boundary conditions and loading methods of all models are consistent; S6.1.

2. Analysis type selection: Select NONLINEAR STATIC ANALYSIS to capture the actual load behavior of the arch foot under different optimization schemes; S6.1.

3. Solution setting and execution: Set the solver accuracy, number of iterations and convergence criteria, perform the force analysis of the optimization scheme, and calculate the stress distribution and deformation of the arch foot under each scheme; S6.1.

4. Stress result extraction: Extract stress data under each optimization scheme, including maximum stress, shear stress, and principal stress, with special attention paid to the changes in stress concentration areas after optimization; S6.1.

5. Generation of deformation and stress distribution diagrams: Use the post-processing function of MIDAS / FEA to generate deformation diagrams and stress distribution diagrams for each optimized design scheme, and intuitively display the structural stress characteristics under different schemes; S6.

2. Comparative evaluation of the optimized design and the original design S6.2.

1. Review of original design analysis results: Review the stress analysis results of the original design again to ensure a consistent benchmark with the optimized solution; S6.2.

2. Stress comparison analysis: Compare the stress data of each optimized design scheme with the original design scheme, analyze the changes in the maximum stress and stress concentration area, and evaluate the effect of each scheme in reducing stress concentration and improving structural performance; S6.2.

3. Structural safety assessment: Based on the stress results of each scheme, strength and stability verification shall be conducted to determine the degree of improvement in safety of the optimized scheme; S6.2.

4. Comprehensive performance comparison: Consider the stress distribution, deformation, and construction feasibility factors of each scheme, and comprehensively evaluate the superiority of each optimization scheme, especially the rationality and economy of the filling length and partial filling method; S6.2.

5. Selection of the best solution: Based on the comprehensive performance evaluation results, select the optimal concrete filling length and partial filling method to provide a basis for the final design.

8. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing its installation according to claim 7 is characterized in that: The implementation process of step S7 is as follows: S7.

1. Optimized installation method for steel box concrete arch footing: S7.1.

1. Construction condition analysis: Based on the actual construction conditions of the bridge, analyze the factors that may affect the concrete filling of the arch foot, including the on-site construction environment, equipment limitations, and construction period requirements; S7.1.

2. Installation sequence design: According to the optimized design plan, formulate the specific sequence of arch foot installation, clarify the sequence of concrete filling and the construction rhythm to ensure the structural safety during the construction process; S7.1.

3. Determination of filling process: Determine the specific process of concrete filling, including pouring method, maintenance measures, and quality control points, to ensure the operability and reliability of the filling process; S7.1.

4. Quality control measures: Develop a quality control plan for concrete filling and set the parameters and indicators that need to be monitored during the construction process, including concrete strength and arch foot deformation, to ensure construction quality; S7.1.

5. Preparation of construction method manual: Combined with the optimized design and installation methods, a detailed construction method manual is prepared, including operation steps, precautions, and quality control points, to provide guidance for the construction team; S7.

2. Implement optimized installation methods.

9. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing the installation according to claim 8 is characterized in that: The implementation process of step S7.2 is as follows: S7.2.

1. Flowchart drawing: Draw a flow chart for optimizing the installation of the steel box concrete arch foot, visually showing the sequence and key points of each construction step; S7.2.

2. Operational details: Describe in detail in the manual the operational details of each construction step, including mixing, transportation, pouring, vibrating, and curing of concrete; S7.2.

3. Selection of construction tools and equipment: List the required construction tools and equipment, clearly identify the tools and equipment used in each construction step, and their configuration requirements; S7.2.

4. Construction node monitoring: Set monitoring measures for key construction nodes, including deformation monitoring after the arch foot concrete pouring is completed and actual measurement of concrete strength, to ensure the safety and quality of the construction process; S7.2.

5. Construction training and drills: Before formal construction, the construction team shall be trained and trained on the operating procedures to ensure that all construction personnel are familiar with the optimized installation methods and operating procedures.

10. The method for analyzing the stress performance of the arch foot of a large-span steel box basket arch bridge and optimizing its installation according to claim 9 is characterized in that: The implementation process of step S8 is as follows: S8.

1. Evaluation of technical and economic indicators for optimizing design solutions and installation methods; S8.1.

1. Construction efficiency evaluation: Analyze the impact of optimized design solutions and installation methods on construction efficiency, including shortening construction time and simplifying the construction process, and quantify the improvement in construction efficiency; S8.1.

2. Project cost analysis: Calculate the construction cost based on the material consumption of the optimized design and the complexity of the construction process, compare the cost difference between the optimized solution and the original design, and evaluate the economic benefits; S8.1.

3. Environmental benefit assessment: Analyze the contribution of the optimization scheme to material conservation and carbon emission reduction during construction, and conduct quantitative assessment based on environmental indicators; S8.1.

4. Comprehensive technical and economic analysis: Conduct a comprehensive analysis of construction efficiency, project cost, and environmental benefit indicators, calculate the overall technical and economic indicators of the optimization plan, and evaluate the feasibility of its promotion and application; S8.1.

5. Write an evaluation report: Summarize the evaluation results of technical and economic indicators and write a detailed technical and economic analysis report to provide a basis for subsequent project decision-making; S8.

2. Promotion and application; S8.2.

1. Application scenario analysis: Analyze the applicability of the optimized design solution and installation method in other steel box basket arch bridge projects and identify engineering projects with similar structural characteristics; S8.2.

2. Development of promotion and application strategies: Development of application strategies for promotion of optimized design solutions, including technical publicity, demonstration project construction, and technical training measures, to promote the widespread application of the solutions; S8.2.

3. Preparation of complete technical reports: Based on the research results, prepare a complete technical report and construction instruction manual, including design points, construction process, quality control content, to provide reference for similar projects; S8.2.

4. Policy and Standard Recommendations: Based on the research results, propose standardized recommendations for optimizing design solutions and installation methods, and promote their inclusion in relevant design specifications and construction standards.

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