A method for converting a bridge BIM model into a bridge FEM model

Abstract

The embodiment of the application provides a kind of bridge BIM model to bridge FEM model conversion method, it is related to bridge design technical field, method includes: from bridge BIM model, export IFC data to extract the cross-sectional characteristics of bridge component, and then determine cross-sectional geometric parameters;Again, the cross-sectional geometric parameters of mutually different cross-sections are stored as component information files, and the geometric parameters of mutually different cross-sections are stored as cross-sectional information files;Based on component information file, connection relationship file for storing the connection relationship of adjacent bridge components is constructed, boundary condition file for storing the boundary information of bridge as a whole and node information file for storing the centroid point coordinates of bridge component, finally, these JSON file formats are converted into the format file of bridge FEM model.The application is used to solve the problem that BIM model and FEM model need to be modeled separately in the process of bridge design, the model cannot be reused, resulting in low efficiency of bridge design.

Description

Technical Field

[0001] This invention relates to the field of bridge design technology, and more specifically to a method for converting a bridge BIM model into a bridge FEM model. Background Technology

[0002] During the bridge structure design phase, a 3D visualization model is created on a Building Information Modeling (BIM) platform such as Revit to visually represent the bridge's structural form and its final appearance. To verify the rationality of the structural layout and guide the placement of prestressed steel reinforcement, a mechanical analysis model is created in finite element software such as Midas Civil. In the design phase, the BIM model is primarily used to visualize the bridge's 3D geometry, structural layout, coordinate spatial relationships between components, and integrate engineering information. To verify the feasibility of the structural layout, designers use finite element software to create a finite element model (FEM) to analyze the internal forces of the control sections, thereby evaluating and adjusting the placement of ordinary steel reinforcement and prestressed steel strands.

[0003] In engineering practice, bridge BIM modeling often utilizes platforms such as Revit, while finite element analysis (FEM) typically relies on commercial software like Midas / Civil, ABAQUS, and ANSYS. Achieving efficient interoperability between BIM and FEM models in bridge engineering is crucial for reducing repetitive modeling work during the design process and improving the efficiency of preprocessing for FEM analysis. However, the two types of software differ fundamentally in their modeling objectives, data structures, and logical expressions. BIM modeling software emphasizes the visual presentation of the model and establishes a deep relationship between geometric and attribute information. Its geometric representation is typically based on high-precision triangular meshes, utilizing texture vertices and normal vectors for refined rendering and supporting object-oriented parametric modeling at the underlying level. Common interaction formats include STL, STP, and IFC. Furthermore, the software supports storing and managing rich attribute semantic information. In contrast, finite element software focuses on calculating the mechanical response of the structure. Its model expresses geometry using points, lines, surfaces, and solids. Material, cross-section, and constraint attributes are used to describe the mechanical behavior of the structure. The model mesh focuses on the number of integration points and element quality, directly impacting computational accuracy and efficiency. When the preprocessing capabilities of finite element software are insufficient to support complex modeling, it is often used in conjunction with geometric modeling software such as Solidworks and Hypermesh, as well as mesh generation software. Due to the aforementioned reasons, there is a lack of a universal data exchange interface between BIM software and finite element software for interoperability. This necessitates separate modeling in bridge design, preventing model reuse and resulting in low efficiency in bridge design work.

[0004] Currently, the conversion between BIM and FEM models requires manual multi-software collaborative conversion or the development of custom algorithms. While existing technologies have expanded the application of BIM software in bridge structural analysis, they rely on the BIM software's programming interface, necessitating secondary development to extract and access the underlying data of the BIM model. Furthermore, the conversion process depends on the integrity of the BIM model information; essential information for finite element analysis, such as nodes, elements, construction stages, boundary conditions, and material parameters, must be explicitly defined and added in the BIM model beforehand. Additionally, to meet conversion requirements, a BIM model needs to be specifically constructed or modified, rather than directly utilizing the BIM model established in the design phase. These issues prevent the rapid generation of FEM models from BIM models, hindering the improvement of bridge design efficiency and failing to meet the demands of automated, intelligent, and high-fidelity engineering. Summary of the Invention

[0005] In view of this, it is necessary to provide a method for converting bridge BIM models into bridge FEM models to solve the technical problem that bridge design requires separate modeling of BIM and FEM models and the inability to reuse models, resulting in low efficiency in bridge design work.

[0006] To address the aforementioned problems, this invention provides a method for converting a bridge BIM model into a bridge FEM model, comprising:

[0007] Export IFC data from bridge BIM model;

[0008] Based on the IFC data, the cross-sectional features of bridge components are extracted, the cross-sectional geometric parameters are determined based on the cross-sectional features, and dissimilar cross-sections are selected. The cross-sectional geometric parameters are stored as component information files, and the cross-sectional geometric parameters of the dissimilar cross-sections are stored as cross-sectional information files.

[0009] Based on the component information file, a connection relationship file storing the connection relationship between adjacent bridge components, a boundary condition file storing the overall boundary of the bridge, and a node information file storing the coordinates of the centroid points corresponding to the bridge components are constructed respectively.

[0010] The component information file, the cross-section information file, the connection relationship file, the boundary condition file, and the node information file are converted into their formats to obtain the format file of the bridge FEM model.

[0011] In one possible implementation, exporting IFC data from the bridge BIM model includes:

[0012] Export the bridge BIM model as an IFC model;

[0013] Geometric information and attribute semantic information of bridge components under different component types are extracted from the IFC model;

[0014] When the bridge component has a global identifier, the global identifier is formatted and standardized, and the geometric information and attribute semantic information of the bridge component are associated with the global identifier after format standardization.

[0015] When the bridge component lacks a global identifier, a global identifier for the bridge component is generated, and the geometric information and attribute semantic information of the bridge component are associated with the generated component identifier.

[0016] Geometric information with global identifiers is stored as IFC data in GLB format.

[0017] In one possible implementation, extracting the cross-sectional features of bridge components based on the IFC data includes:

[0018] The triangular facet data of each bridge component is obtained by parsing the IFC data;

[0019] The extension direction vector and length of the bridge component are calculated based on the triangular facet data to determine the cut-off position of the cross section, and the cross section geometry data corresponding to each cut-off position is extracted.

[0020] A pre-constructed bridge section template database is obtained, and the bridge section template database is retrieved based on the cross-sectional geometric data to obtain the cross-sectional features of the bridge components. The bridge section template database stores the cross-sectional features of the corresponding cross-sectional types under various component types of bridge components.

[0021] In one possible implementation, determining the cross-sectional geometric parameters and filtering out dissimilar cross-sections based on the cross-sectional features includes:

[0022] The type identifier index, number of inner and outer contour points, and two-dimensional coordinates of the inner and outer contour points of the bridge component corresponding to the cross-sectional features are obtained from the cross-sectional features.

[0023] The cross-sectional geometric parameters of the cross section are calculated by calling the calculation function according to the type identifier index. The calculation function is used to calculate the cross-sectional geometric parameters of the cross section based on the number of inner and outer contour points and the two-dimensional coordinates of the inner and outer contour points.

[0024] Cross sections with different geometric parameters are selected from the cross sections as distinct cross sections.

[0025] In one possible implementation, the connection relationship file is constructed as follows:

[0026] Parse the cross-sectional geometric parameters in the component information file to obtain the centroid coordinates of the corresponding cross-section of each bridge component;

[0027] When adjacent bridge components are of the same type, the endpoint coordinates of the adjacent bridge components are determined as the matching master node coordinates and slave node coordinates;

[0028] When adjacent bridge components are of different component types, the master and slave node components are determined according to the connection relationship of the bridge components, and the centroid coordinates of the master bridge component in the master and slave node components are determined.

[0029] For each of the main bridge components, calculate the spatial distance between the centroid coordinates of the main bridge component and the centroid coordinates of the secondary bridge components in the main-secondary node components;

[0030] The coordinates of the centroid point corresponding to the closest spatially distant secondary bridge component and the centroid point coordinates of the primary bridge component are determined as the matching secondary node coordinates and primary node coordinates.

[0031] Store the matching master node coordinates, slave node coordinates, and the corresponding bridge component type name as a connection relationship file.

[0032] In one possible implementation, storing the matched master node coordinates, slave node coordinates, and corresponding bridge component type names as a connection relationship file includes:

[0033] The target database is queried based on the component type name of the matched bridge component to obtain the corresponding type identifier index. The target database stores semantic information about the connection relationship of bridge components.

[0034] Based on the type identifier index, the corresponding number of coupled degrees of freedom and the coupled degrees of freedom index are obtained by querying the target database.

[0035] Obtain a preset coupling constraint template, and write the corresponding master node coordinates, slave node coordinates, number of coupling degrees of freedom, and coupling degree of freedom index of the matched bridge components into the coupling constraint template to obtain a coupling constraint dictionary;

[0036] The coupling constraint dictionary is stored as a connection relationship file.

[0037] In one possible implementation, the boundary condition file is constructed as follows:

[0038] Parse the cross-sectional geometric parameters in the component information file to obtain the centroid coordinates of the corresponding cross-section of each bridge component;

[0039] Determine the sequence of centroid points of the main girder of the bridge in the extension direction of the bridge components, and take the centroid points at the beginning and end of the centroid point sequence as the boundary points of the superstructure.

[0040] Identify the bridge abutment structure and select the centroid of the bottom section of the bridge component in the abutment structure as the boundary point of the substructure.

[0041] The coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, the component type names of the bridge components corresponding to the upper structure boundary points, and the component type names of the bridge components corresponding to the lower structure boundary points are stored as boundary condition files.

[0042] In one possible implementation, storing the coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, the component type names of the bridge components corresponding to the upper structure boundary points, and the component type names of the bridge components corresponding to the lower structure boundary points as a boundary condition file includes:

[0043] The target database is queried based on the component type name of the bridge component corresponding to the boundary point of the superstructure and the component type name of the bridge component corresponding to the boundary point of the substructure to obtain the type identifier index of the corresponding component type name. The target database stores the semantic information of the bridge boundary conditions.

[0044] Based on the type identifier index, query the degree of freedom constraints of the upper structure boundary points and the lower structure boundary points from the target database;

[0045] Obtain a preset boundary condition template, and write the coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, and the degree of freedom constraints into the boundary condition template to obtain a boundary condition dictionary;

[0046] Store the boundary condition dictionary as a connection relationship file.

[0047] In one possible implementation, the format file of the bridge FEM model is obtained through format conversion in the following manner:

[0048] Read the coordinates of the centroid points corresponding to the bridge components stored in the node information file, and write the node module of the overall model file after assigning a node index to each centroid point coordinate.

[0049] Write the cross-sectional geometric parameters of the distinct cross-sections stored in the cross-sectional information file into the cross-sectional definition module of the overall model file;

[0050] The bridge components are identified by reading the component information file, and the corresponding section number of the bridge component is retrieved from the section information file.

[0051] Associate the node index of the bridge component with the section number, and write the associated line component parameters into the line component module of the overall model file;

[0052] The coordinates of the master node and slave node corresponding to the bridge component matched in the connection relationship file are replaced with the node index of the bridge component and then written into the coupling constraint module of the overall model file.

[0053] The coordinates of the upper structure boundary points and the lower structure boundary points stored in the boundary condition file are replaced with the node indexes of the bridge components and then written into the boundary condition module of the overall model file.

[0054] The material data of the bridge components are written into the material module of the overall model file to obtain the format file of the bridge FEM model.

[0055] In one possible implementation, the method further includes:

[0056] The bridge FEM model file is imported into the finite element system for analysis to obtain the bridge FEM model.

[0057] The beneficial effects of adopting the above implementation method are as follows: The method for converting a bridge BIM model to a bridge FEM model provided by this invention first exports IFC data from the bridge BIM model, achieving separation of data and model, and avoiding secondary development using the programming interface of BIM software to extract the underlying data of the BIM model. Furthermore, the exported IFC data is directly used for data processing, storing and constructing corresponding JSON files according to data type, and then integrating them to form the format file of the bridge FEM model. In this way, automatic and rapid conversion from bridge BIM model to FEM model is achieved only at the data processing level. This conversion process is directly applicable to various bridge BIM models, demonstrating strong versatility. Moreover, there is no need to specifically construct the BIM model or add the information necessary for finite element analysis at the model level, improving the model conversion efficiency and thus improving the efficiency of bridge design work. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 A flowchart illustrating the method for converting a bridge BIM model into a bridge FEM model provided by this invention;

[0060] Figure 2 The rendering of the bridge BIM model provided by this invention;

[0061] Figure 3 A schematic diagram illustrating the principle framework of the method for converting a bridge BIM model to a bridge FEM model provided by this invention;

[0062] Figure 4 A schematic diagram illustrating the principle framework for bridge BIM model data parsing and storage provided by this invention;

[0063] Figure 5 A schematic diagram illustrating the principle framework of the automatic extraction process of geometric features of bridge components provided by this invention;

[0064] Figure 6 This is a schematic diagram illustrating the processing of bridge component connection relationships and model boundary conditions provided by the present invention.

[0065] Figure 7 A simplified structural diagram of the target database provided by this invention;

[0066] Figure 8 A schematic diagram illustrating the generation principle of the bridge FEM model format file provided by this invention;

[0067] Figure 9 The image shows a rendering of the bridge FEM model provided by this invention. Detailed Implementation

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0069] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0070] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0071] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0072] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0073] The method for converting a bridge BIM model to a bridge FEM model provided in this invention can be applied to the theoretical design of bridge engineering projects. The execution entity can be a server, terminal, or remote cloud device. After bridge engineers design and upload the bridge BIM model, they can use the method provided in this invention to directly generate a format file for exporting the bridge FEM model. This format file can be directly imported into a finite element analysis system or software for analysis, outputting the corresponding bridge BIM model and providing a theoretical basis for the subsequent implementation and operation and maintenance of bridge engineering projects.

[0074] The method for converting a bridge BIM model into a bridge FEM model provided by this invention is described in detail below.

[0075] Figure 1 The flowchart illustrates the method for converting a bridge BIM model to a bridge FEM model provided by this invention. Figure 1 As shown, the method for converting a bridge BIM model into a bridge FEM model can be achieved through the following steps 101 to 104, which are explained in detail below.

[0076] Step 101: Export IFC data from the bridge BIM model.

[0077] like Figure 2 As shown, the first step in converting a bridge BIM model to a bridge FEM model is the separation of the model and the data. The rendering of the bridge BIM model is shown below. Figure 3As shown, the bridge BIM model contains 124 bridge components, including 103 continuous beam segments, 12 piers, 6 crossbeams, and 3 abutments. During model processing, the bridge BIM model can be directly imported into the Revit platform, and then Industry Foundation Classes (IFC) data can be exported from the bridge BIM model using the Revit platform. IFC data includes the geometric and attribute information of the bridge BIM model. Here, the geometric and attribute information of the bridge BIM model is separated from the IFC data for storage. In the extracted IFC data, the geometric information is mainly stored in triangular facets in GL transfer format binary (glTF Binary, GLB) format, resulting in GLB file data. Attribute semantic information such as materials, component types, component names, and spatial relationships between components is stored separately in a database. The GLB file data is used for subsequent modeling, while the attribute semantic information stored in the database is not accessed.

[0078] Step 102: Extract the cross-sectional features of bridge components based on IFC data, determine the cross-sectional geometric parameters based on the cross-sectional features and filter out dissimilar cross-sections, and store the cross-sectional geometric parameters as component information files and the cross-sectional geometric parameters of dissimilar cross-sections as cross-sectional information files.

[0079] See also Figure 2 The second step in converting a bridge BIM model to a bridge FEM model is the automatic extraction of geometric features. Specifically, using GLB file data as input, cross-sectional features are first extracted to obtain the centroid coordinates and geometric parameters of the bridge component cross-sections, thus simplifying the model from a three-dimensional solid to a one-dimensional beam-and-bar element. The specific process is as follows: read the GLB file data, calculate the extension axis vector of the component, extract the end and middle sections of the component, and obtain two types of cross-sectional geometric data as cross-sectional features: the centroid coordinates and geometric parameters of the cross-section. Further, a pre-built bridge cross-section template database is used for traversal matching. This pre-built database stores common bridge cross-section templates. By traversing and matching the extracted cross-sections in the bridge cross-section template database, the cross-section shape, cross-section type, and component type name can be identified, and a cross-section type index ID is established for each cross-section.

[0080] Furthermore, this embodiment of the invention automatically extracts all cross-sectional geometric parameters from the cross-sectional features using a geometric parameter extraction algorithm. On one hand, it integrates all cross-sectional geometric parameters, centroid coordinates, and other geometric features, saving them as a component information file in JSON format. On the other hand, it identifies cross-sections with distinct geometric parameters. Specifically, based on the cross-sectional geometric parameters determined by the cross-sectional features, it filters out cross-sections with different geometric parameters and saves the cross-sectional geometric parameters of these distinct cross-sections as a cross-sectional information file, also in JSON format. Additionally, the cross-sectional information JSON file also stores the cross-sectional name and cross-sectional identifier of each distinct cross-section.

[0081] Step 103: Based on the component information file, construct the connection relationship file storing the connection relationship between adjacent bridge components, the boundary condition file storing the overall boundary of the bridge, and the node information file storing the coordinates of the centroid points corresponding to the bridge components.

[0082] See also Figure 2 The third step in converting a bridge BIM model to a bridge FEM model is the automatic assignment of connection relationships and boundary conditions. Here, the geometric parameters of each section stored in the component information file are used to determine the constraints of the bridge components and the model's boundary points, with the aim of assigning connection relationships and boundary conditions to the bridge components. Thus, by adding connection relationships to the bridge components and assigning boundary conditions to the model as a whole, the mechanical characteristics of the model are expressed.

[0083] For the connection relationship between adjacent bridge components, this embodiment of the invention identifies spatially adjacent bridge components requiring coupling constraints by reading the coordinates of the centroid points of the bridge component cross-sections from the component information file, thereby determining the master-slave node coordinate pairs. For model boundary conditions, the coordinates of the boundary points of the overall bridge boundary are identified. Furthermore, this embodiment of the invention constructs a bridge connection and boundary information database as a target database. The target database is accessed using the component type name to add the number of coupling degrees of freedom and degree-of-freedom index identifiers to the master-slave node coordinate pairs, thus determining the coupling constraint conditions. Furthermore, the target database can also be used to add degree-of-freedom constraints to the boundary point coordinates to determine the model boundary conditions. Finally, the coupling constraint conditions of all adjacent bridge components are integrated and saved as a connection relationship file in JSON format, i.e., a connection relationship JSON file. Simultaneously, all model boundary conditions are integrated and saved as a boundary condition file, also in JSON format, i.e., a boundary condition JSON file.

[0084] To facilitate the input of node information, this embodiment of the invention extracts the coordinates of all centroid points of the bridge components from the component information file, writes them into and stores them separately as a node information file, which is also in JSON format, i.e., a node information JSON file.

[0085] Step 104: Convert the format of the component information file, section information file, connection relationship file, boundary condition file, and node information file to obtain the format file of the bridge FEM model.

[0086] See also Figure 2 The fourth step in converting a bridge BIM model to a bridge FEM model is to simplify the import of the model into the finite element analysis system. Through the first, second, and third steps mentioned above, five types of JSON files are obtained: component information JSON file, section information JSON file, connection relationship JSON file, boundary condition JSON file, and node information JSON file. Next, preset material properties (i.e., the material properties of the bridge structure) are obtained and then integrated with the five JSON files. During the integration process, the corresponding parameters in the JSON files are extracted and written to the corresponding modules in the overall model file, and the preset material properties are also written to the overall model file, thus completing the data writing to the overall model file. The overall model file is in TXT format, which conforms to the syntax specifications of the finite element analysis system or software and can be used as the format file for the bridge FEM model, thus achieving the format conversion of the file data. The bridge FEM model file can be directly imported into the finite element analysis system or software for analysis and processing to obtain the bridge FEM model.

[0087] This invention first extracts IFC data from the bridge BIM model, separating the data from the model and avoiding secondary development using BIM software's programming interface to extract the underlying data of the BIM model. Furthermore, the extracted IFC data is directly processed, and various JSON files are constructed and stored according to data type before being integrated to form the bridge FEM model format file. This achieves automatic and rapid conversion from bridge BIM model to FEM model solely at the data processing level. The conversion process is directly applicable to various bridge BIM models, demonstrating strong versatility. Moreover, it eliminates the need for targeted construction of the BIM model and the addition of information required for finite element analysis, improving model conversion efficiency and consequently, the efficiency of bridge design work.

[0088] In one possible implementation, exporting IFC data from a bridge BIM model can be achieved in the following ways, as detailed below.

[0089] First, the bridge BIM model is exported as an IFC model. Then, the geometric information and attribute semantic information of the bridge components under different component types are extracted from the IFC model.

[0090] like Figure 4As shown, during the model-to-database separation process, the bridge BIM model can be directly exported to IFC format in the Revit platform. The Web-IFC API is then called to parse the IFC model and identify the component type IDs. Here, the component type specifically refers to the type of bridge component, such as bridge, column, or slab. The component type IDs are IfcBeam (beam), IfcColumn (column), IfcSlab (slab), etc. Then, based on the component type ID, all instances of bridge components are traversed to separate the bridge component information. This allows for the extraction of the geometric information and attribute semantic information of each bridge component under the specified component type.

[0091] When a bridge component has a global identifier, the component identifier is formatted according to specifications, and the geometric and attribute semantic information of the bridge component is associated with the formatted global identifier. When a bridge component lacks a global identifier, a global identifier is generated for the bridge component, and the geometric and attribute semantic information of the bridge component is associated with the generated component identifier.

[0092] In the IFC model, the geometric information and attribute semantic information of the same bridge component should be associated accordingly, generally through a global identifier, denoted as a GUID. In this embodiment of the invention, after separating the bridge component information, a judgment is first made to determine whether the bridge component contains a global identifier. If so, it means that the geometric information and attribute semantic information of the same bridge component have been associated using a global identifier GUID. The component identifier is then formatted, typically by removing spaces, invalid characters, or garbled characters from the global identifier to standardize it. If not, it means that the geometric information and attribute semantic information of the same bridge component have not been associated using a global identifier GUID. A global identifier is then generated for association, and the generation process can call the UUIDv5 algorithm under the RFC4122 standard for naming and generation. The generated global identifier is then used to associate the geometric information and attribute semantic information of the bridge component. This ensures that the attribute semantic information and geometric information of the same bridge component can be mutually associated.

[0093] Finally, the geometric information with component identifiers is stored as IFC data in GLB format.

[0094] Here, for the geometric information of bridge components with global identifiers, the mesh data of the bridge components, such as vertices, indices, and normals, is extracted. Then, the coordinates are normalized to a common coordinate system, and further, a binary file in GLB format is generated. Finally, the binary files of all bridge components are integrated and stored as IFC data in GLB format. As for the attribute semantic information, all attribute definitions are traversed, the key-value pairs corresponding to each attribute are obtained, and stored in the relevant database.

[0095] In this embodiment of the invention, by exporting IFC data from the bridge BIM model and separating and extracting geometric and attribute semantic information, and then storing it in GLB format for subsequent model conversion, the dependence on the original bridge BIM model during model conversion is significantly reduced. This enables independent management and efficient retrieval of model geometric and attribute information, shifting model conversion from the model level to the data level, and allowing model conversion to be quickly achieved using lightweight industrial basic data.

[0096] In one possible implementation, the cross-sectional features of bridge components can be extracted from IFC data, which can be achieved in the following ways, as detailed below.

[0097] First, the IFC data is parsed to obtain the triangular facet data of each bridge component. Then, the extension direction vector and length of the bridge component are calculated based on the triangular facet data to determine the section cutting position, and the cross-sectional geometry data of the corresponding section at each cutting position is extracted.

[0098] like Figure 5 As shown, for IFC data in GLB format, the geometric information is parsed and obtained. Then, the triangular facets of the bridge components are read from the geometric information. The extension direction vector of the bridge components is directly calculated using the triangular facet data, and the length of the bridge components can be directly determined.

[0099] Furthermore, by extracting the cross-sections of the components, the ends and middle sections of the bridge components can be extracted based on the extension direction vector and length. Then, the geometric data of the cross-sections can be extracted. For each cross-section, the two-dimensional coordinates, three-dimensional coordinates, and quantity of the inner and outer contour points can be directly extracted. Furthermore, the centroid coordinates of the bridge component cross-section can be calculated using a bounding box, and features such as the inner and outer contour edge vectors can be further calculated. During data storage, the two-dimensional coordinates, three-dimensional coordinates, quantity, centroid coordinates, and inner and outer contour edge vectors of the cross-sections can all be stored in a temporary dictionary structure.

[0100] Next, a pre-built bridge section template database is obtained, and the bridge section template database is retrieved based on the section geometry data to obtain the section features of the bridge components.

[0101] Here, the bridge section template database stores the cross-sectional features of various bridge component types corresponding to different section types. Component types include continuous beam segments, piers, cross bracing, and abutments, while section types include circular, single-box single-cell, and rectangular. When constructing the bridge section template database, typical bridge structures can be selected from actual bridge design drawings and publicly available general atlases for parametric representation to form the bridge section template library. The parametric operation specifically involves adding bridge component type names, adding section type identifiers, and extracting the two-dimensional coordinates of bridge component vertices. All these parameters are then written into a database to obtain the bridge section template database.

[0102] Here, the extracted cross-sectional geometric data can be used to retrieve the bridge cross-section template database. By traversing and matching, the cross-section type identifier corresponding to the best matching cross-section and the bridge component type name are obtained, and these are also written into a temporary dictionary structure storing each feature item, thus obtaining the cross-sectional features of the bridge component. Here, the temporary dictionary structure can be in JSON format, thereby storing the cross-sectional features of the bridge component as an intermediate JSON file.

[0103] In this embodiment of the invention, the cross-sectional features of bridge components are directly extracted from industrial basic data. The extraction process is entirely based on the triangular facet data of each bridge component, without relying on the preset semantic tags or specific modular parameters in the bridge BIM model. This data calculation process, which is not specific to any particular bridge BIM model, is applicable to the conversion and processing of various bridge BIM models.

[0104] In one possible implementation, determining the cross-sectional geometric parameters and selecting distinct cross-sections based on the cross-sectional features can be achieved in the following ways, which are explained in detail below.

[0105] First, obtain the type identifier index, the number of inner and outer contour points, and the two-dimensional coordinates of the inner and outer contour points of the bridge components from the cross-sectional features.

[0106] See also Figure 5 By parsing the intermediate JSON file that stores the cross-sectional features of bridge components, we can obtain feature data items such as the type identifier index of the corresponding cross-section of the bridge component, the number of inner and outer contour points, and the two-dimensional coordinates of the inner and outer contour points.

[0107] Next, the cross-sectional geometric parameters of the cross section are calculated by calling the calculation function according to the type identifier index. The calculation function is used to calculate the cross-sectional geometric parameters of the cross section based on the number of inner and outer contour points and the two-dimensional coordinates of the inner and outer contour points.

[0108] Here, this embodiment of the invention proposes a geometric parameter extraction algorithm as a calculation function to calculate the cross-sectional geometric parameters of each cross-section, specifically calculating the key dimensions of each cross-section, such as area and perimeter. Since the number of inner and outer contour points and their two-dimensional coordinates are determined, the corresponding area and perimeter of the cross-section can be calculated based on the spatial position of these two-dimensional coordinates. In specific calculations, the calculation function can be called one by one according to the cross-section type identifier index to calculate the cross-sectional geometric parameters of all cross-sections.

[0109] Finally, cross sections with different geometric parameters are selected from the cross sections as distinct cross sections.

[0110] Here, since the geometric parameters of each section are determined, sections with different geometric parameters can be selected as distinct sections. This means choosing sections with different geometric parameters, such as sections with different key dimensions. Adding the corresponding section name and section type identifier to the geometric parameters of these distinct sections allows them to be stored as a JSON file containing section information. Furthermore, by adding the centroid coordinates of the section to the calculated geometric parameters, they can be stored as a JSON file containing component information.

[0111] In this embodiment of the invention, based on the extracted cross-sectional features, a geometric parameter extraction algorithm is designed to calculate the geometric parameters of each cross-section and the distinct cross-sections one by one. These parameters are then stored in corresponding JSON files according to the parameter order of the FEM model. This simplifies the three-dimensional solid bridge components of the bridge BIM model into one-dimensional line components of the FEM model, thus meeting the requirements of the FEM model analysis system.

[0112] After constructing the component information file, this embodiment of the invention further constructs and generates a connection relationship file and a boundary condition file based on the component information file. The connection relationship file records the coupling constraint relationships between various bridge components, while the boundary condition file records the boundary point positions of the overall model. This ensures that the bridge model possesses the important condition of a geometrically invariant system during model transformation, preventing the model's geometric properties from failing.

[0113] The following section details how to construct the connection relationship file.

[0114] First, parse the cross-sectional geometric parameters in the component information file to obtain the centroid coordinates of the corresponding cross-section for each bridge component.

[0115] like Figure 6 As shown, the component information JSON file stores the cross-sectional geometric parameters and the coordinates of the centroid points of additional cross-sections. By parsing the component information JSON file, the centroid coordinates can be read, and further used to determine the coupling constraint relationships between bridge components.

[0116] When adjacent bridge components are of the same type, the coordinates of the adjacent endpoints of the adjacent bridge components are determined as the matching master node coordinates and slave node coordinates.

[0117] In bridges, connected components are typically adjacent. Two adjacent components may be of the same type, such as both being crossbeams. They may also be of different types, for example, one a crossbeam and the other a pier. Therefore, it's necessary to first distinguish the adjacency relationships of bridge components and determine if they are of the same type. If so, the two adjacent components are successfully matched and can be identified as matched bridge components. The coordinates of the adjacent endpoints of the two components are then determined as the master and slave node coordinates of the matched component. No specific constraints are set to determine which component is the master and which is the slave component.

[0118] When adjacent bridge components are of different component types, the master and slave node components are determined according to the connection relationship of the bridge components, and the centroid coordinates of the master bridge component in the master and slave node components are determined.

[0119] See also Figure 6 Accordingly, when determining whether adjacent bridge components are of the same type, if not, the main and secondary node components are first determined based on the connection relationship of the bridge components, that is, the main bridge component and the secondary bridge component are determined, so that the centroid coordinates of the main bridge component can be obtained, while there may be multiple secondary bridge components, which need to be further filtered.

[0120] Furthermore, for each main bridge component, the spatial distance between the centroid coordinates of the main bridge component and the centroid coordinates of the secondary bridge component in the master-slave node components is calculated; the centroid coordinates of the secondary bridge component with the closest spatial distance and the centroid coordinates of the main bridge component are determined as the matching secondary node coordinates and master node coordinates.

[0121] Here, since there may be multiple secondary bridge components adjacent to the main bridge component, it is necessary to screen these secondary bridge components to determine whether they match the main bridge component. For each main bridge component, the spatial distance between the centroid coordinates of the main bridge component and the centroid coordinates of each secondary bridge component can be calculated one by one. Then, the secondary bridge component with the closest spatial distance is selected as the secondary bridge component that successfully matches the current main bridge component. Therefore, the centroid coordinates of this closest secondary bridge component and the centroid coordinates of the main bridge component are determined as the matching secondary node coordinates and main node coordinates. Thus, through a similar calculation method, a matching secondary bridge component can be calculated for each main bridge component.

[0122] Finally, the coordinates of the matched master node, the coordinates of the slave node, and the component type name of the corresponding bridge component are stored as a connection relationship file.

[0123] Here, for the matched primary and secondary bridge components, a pre-defined coupling constraint template can be used to store the corresponding primary node coordinates, secondary node coordinates, and component type names of the primary and secondary bridge components as a JSON file, serving as the connection relationship JSON file. The coupling constraint template is specifically a predefined file with a fixed data format, such as a dictionary. When generating the file, the primary node coordinates, secondary node coordinates, and component type names are written into the corresponding dictionary format positions to form dictionary entries.

[0124] In this embodiment of the invention, by determining the connection relationship between bridge components and storing it as master-slave node coordinates in a JSON file, the semantic rules of the connection relationship are realized into a recognizable and executable logic file.

[0125] In one possible implementation, the coordinates of the matched master node, the coordinates of the slave node, and the component type name of the corresponding bridge component are stored as a connection relationship file. This can be achieved in the following way, as explained in detail below.

[0126] First, the target database is queried based on the component type name of the matched bridge component to obtain the corresponding type identifier index.

[0127] Here, the target database stores semantic information about the connection relationships of bridge components. Due to the different stress characteristics of different bridges, taking a continuous rigid frame bridge as an example, the connection relationships of bridge components are divided into five types: rigid connection between main beam construction sections, rigid connection between main beam and pier, rigid connection between cross bracing and pier, rigid connection between pier and abutment, rigid connection between abutments, and rigid connection between pile foundation and abutment.

[0128] Furthermore, the semantic information of these connections is extracted and stored as a parameterized representation. Specifically, the possible connection relationships involved in bridge components are first determined, semantic information is extracted, and then the semantic information is parameterized as coupling degrees of freedom. After assigning an index to the coupling degrees of freedom, it is written into a database and stored as the target database.

[0129] See Figure 7 The target database contains three tables: a component type index table (bridge componentindex), a boundary condition table (rigid bridge boundary), and a component connection type table (bridge componentindex). The storage locations of the fields in each table are as follows: Figure 7 As shown.

[0130] See also Figure 6 The coordinates of the matching master node, the coordinates of the slave node, and the component type name are pre-stored in an intermediate JSON file. The component type name is obtained by parsing the intermediate JSON file, and then the bridge component index data table of the target database is queried to obtain the type identifier index (ID) corresponding to the component type name one by one.

[0131] Next, based on the type identifier index, query the target database to obtain the corresponding number of coupled degrees of freedom and the coupled degrees of freedom index.

[0132] Based on the matched bridge components, two type identifier indexes can be obtained from the target database. Then, based on the two type identifier indexes, the rigid bridge connection pair data table in the target database can be queried to obtain the fields of the number of coupling degrees of freedom and the coupling degree of freedom index.

[0133] Furthermore, a preset coupling constraint template is obtained, and the coordinates of the master node, the coordinates of the slave node, the number of coupling degrees of freedom, and the index of coupling degrees of freedom corresponding to the matched bridge components are written into the coupling constraint template to obtain a coupling constraint dictionary.

[0134] Here, the coupling constraint template is pre-constructed based on the possible coupling constraint relationships between bridge components. The coordinates of the master node, slave node, number of coupled degrees of freedom, and index of the coupled degrees of freedom for the matched bridge components can be directly filled into the corresponding positions in the coupling constraint template to generate a coupling constraint dictionary entry. Thus, a coupling constraint dictionary entry can be generated for each set of matched bridge components in the same way.

[0135] Finally, the coupling constraint dictionary is stored as a connection relationship file.

[0136] Here, the dictionary entries of coupling constraints corresponding to each set of matched bridge components are summarized and stored in a JSON file to obtain the connection relationship JSON file.

[0137] In this embodiment of the invention, by querying the target database, the coupling constraint relationship corresponding to the matching bridge components can be determined one by one. Then, by using a preset coupling constraint template to store it as a concrete JSON file, the data expression of the coupling constraint relationship of the theoretically matching bridge components is realized.

[0138] The following section details how to construct boundary condition files.

[0139] First, parse the cross-sectional geometric parameters in the component information JSON file to obtain the centroid coordinates of the corresponding cross-section for each bridge component.

[0140] See also Figure 6 Here, by parsing the component information JSON file, we can obtain the centroid coordinates of the corresponding section of each bridge component, which is used for boundary point determination.

[0141] Next, we determine the sequence of centroids of the main girder in the direction of extension of the bridge components, and take the centroids at the beginning and end of the sequence as the boundary points of the superstructure.

[0142] Here, for the superstructure of the bridge BIM model, the main beam of the bridge is directly identified, and then the centroid of the main beam is determined. In the direction of extension of the bridge components corresponding to the main beam, there are multiple centroids, which can form a centroid point sequence. The first and last centroid points in this centroid point sequence can be used as the boundary points of the superstructure.

[0143] On the other hand, the bridge abutment structure is identified, and the centroid of the bottom section of the bridge component in the abutment structure is selected as the boundary point of the substructure.

[0144] For the substructure of the bridge BIM model, the bridge abutment structure is directly identified. Although there are multiple abutments at the bottom of the bridge BIM model, the centroid of the corresponding bottom section of each abutment is selected as the boundary point of the substructure.

[0145] Finally, the coordinates of the superstructure boundary points, the coordinates of the substructure boundary points, the component type names of the bridge components corresponding to the superstructure boundary points, and the component type names of the bridge components corresponding to the substructure boundary points are stored as boundary condition files.

[0146] After determining the boundary points of the superstructure and substructure, the coordinates of the corresponding boundary points can be obtained by querying the centroid coordinates of the cross-sections of the bridge components to which the boundary points are located. Additionally, the component type names of the bridge components to which the superstructure and substructure boundary points belong need to be determined, and then written together with the boundary point coordinates into a JSON file to obtain the boundary condition JSON file.

[0147] In this embodiment of the invention, by determining the boundary conditions of the model, the boundary point coordinates of the upper and lower structures are visualized and stored as a boundary condition file, thereby realizing the mapping and transformation from the semantic rules of the model boundary conditions to a recognizable and executable logic file.

[0148] In one possible implementation, the coordinates of the superstructure boundary points, the coordinates of the substructure boundary points, the component type names of the bridge components corresponding to the superstructure boundary points, and the component type names of the bridge components corresponding to the substructure boundary points are stored as a boundary condition file. This can be achieved in the following ways, which are explained in detail below.

[0149] First, the target database is queried based on the component type names of the bridge components corresponding to the superstructure boundary points and the component type names of the bridge components corresponding to the substructure boundary points to obtain the type identifier index of the corresponding component type names.

[0150] Here, the target database stores semantic information about the connection relationships of bridge components, as well as semantic information about the bridge's boundary conditions. Taking a continuous rigid frame bridge as an example, the boundary conditions of a rigid frame bridge are degree-of-freedom constraints, such as unidirectional movable supports at both ends of the main beam to release longitudinal displacement, and the bottom of the pile foundation being considered as completely fixed. Furthermore, for scenarios where pile foundations are not established in the bridge BIM model, the substructure boundary conditions should consider the bottom of the abutment to be completely fixed. Here, based on the semantic expression of the boundary conditions involved in the bridge BIM model, key semantic information can be parameterized and written into a database as the target database.

[0151] See Figure 6 The boundary points of the superstructure and the boundary points of the substructure, as well as the component type names of the bridge components to which they belong, are pre-stored in an intermediate JSON file. By parsing the intermediate JSON file to obtain the component type names, and then querying the bridge component index data table in the target database, the type identifier index (ID) corresponding to each component type name can be obtained one by one.

[0152] Next, based on the type identifier index, the degree of freedom constraints of the upper structure boundary points and the lower structure boundary points are queried from the target database.

[0153] Here, based on the type identifier index obtained from the target database, the rigidbridge boundary data table of the target database is queried one by one to obtain the field of the Freedom constraint, thereby obtaining the degree of freedom constraint of the upper structure boundary point and the lower structure boundary point.

[0154] Furthermore, a preset boundary condition template is obtained, and the coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, and the degree of freedom constraints are written into the boundary condition template to obtain a boundary condition dictionary.

[0155] Here, the boundary condition template is pre-constructed based on the possible boundary conditions of the overall bridge boundary. Specifically, it is a predefined file with a fixed data format, such as a dictionary format. When generating the file, the coordinates of the boundary points of the superstructure, the coordinates of the boundary points of the substructure, and the degree of freedom constraints are written into the corresponding positions to generate a boundary condition dictionary entry.

[0156] Finally, the boundary condition dictionary is stored as a connection relationship file.

[0157] Here, by summarizing all the generated boundary condition dictionary entries and storing them in a single JSON file, we obtain the boundary condition JSON file.

[0158] In this embodiment of the invention, the boundary conditions of a bridge BIM model can be determined by querying a target database. Then, a pre-defined boundary condition template is used to store the boundary conditions as a concrete JSON file, thus realizing a data-driven representation of the theoretical overall boundary conditions of the bridge. Combined with a connection relationship file that data-driven represents the coupling constraint relationships of matched bridge components, the model possesses a geometrically invariant system, laying the data foundation for the subsequent generation of a bridge FEM model.

[0159] In this embodiment of the invention, after generating component information files, cross-section information files, connection relationship files, boundary condition files, and node information files one by one, these JSON files are then converted into formats according to the core modules required by the finite element analysis system or software, and then integrated to finally convert them into a format file of a bridge FEM model that can be analyzed by the finite element analysis system or software.

[0160] In one possible implementation, the format file of the bridge FEM model can be obtained by format conversion as follows, as detailed below.

[0161] Firstly, the coordinates of the centroids of the bridge components stored in the node information file are read, and a node index is assigned to each centroid coordinate before being written into the node module of the overall model file.

[0162] like Figure 8 As shown, for the node information JSON file, the coordinates of the centroid points corresponding to the bridge components can be obtained by direct reading, and then node indexes can be assigned to the centroid point coordinates. Here, a unique node index identifier (ID) is automatically assigned to each centroid point coordinate, which means that a node index is assigned to the bridge component, and then written into the node module of the overall model file according to the node definition format required by the finite element analysis system or software.

[0163] Secondly, the definition parameters of the distinct cross sections stored in the cross section information file are written into the cross section definition module of the overall model file.

[0164] Here, by reading the JSON file containing the cross-section information, all fields are extracted to obtain the cross-sectional geometric parameters of the stored dissimilar cross-sections, as well as the added cross-section names and cross-section type identifiers. This data is then written sequentially into the cross-section definition module of the overall model file.

[0165] Thirdly, the bridge components are identified by reading the component information file, the corresponding section number of the bridge component is queried from the section information file, the node index of the bridge component is mapped and associated with the section number, and the associated line component parameters are written into the line component module of the overall model file.

[0166] Here, the construction of the line component module relies on endpoint indices and section numbers. When determining the section number, all relevant bridge components are first identified by reading the component information JSON file. Then, based on these bridge components, the section information JSON file is queried to obtain the corresponding section names. The section names are then mapped to obtain the corresponding section numbers. The endpoint index can be directly obtained by reading the node index assigned to the centroid coordinates of the bridge component. Finally, the endpoint indexes are associated with the corresponding section numbers to generate the corresponding line component parameters, which are then sequentially written into the line component module of the overall model file.

[0167] Fourthly, the coordinates of the master nodes and slave nodes corresponding to the bridge components matched in the connection relationship file are replaced with the node indices of the bridge components and then written into the coupling constraint module of the overall model file.

[0168] For the connection relationship JSON file, the node indices assigned to each bridge component are first read, and the corresponding master node coordinates and slave node coordinates are replaced with the node indices before being written. Specifically, the connection relationship JSON file is constructed based on the coupling constraint dictionary. By reading the coupling constraint dictionary, the matching bridge components with coupling constraint relationships can be determined. The master node coordinates and slave node coordinates of these matching bridge components are replaced with the corresponding bridge component node indices, and then the parameters of the coupling constraint dictionary are written into the coupling constraint module of the overall model file in sequence.

[0169] Fifthly, the coordinates of the upper structure boundary points and the lower structure boundary points stored in the boundary condition file are replaced with the node indexes of the bridge components and then written into the boundary condition module of the overall model file.

[0170] For the boundary condition JSON file, the node indices assigned to each bridge component are first read, and the boundary point coordinates are replaced with the node indices before being written. Specifically, the boundary condition JSON file is constructed based on the boundary condition dictionary. By reading the boundary condition dictionary, the coordinates of the superstructure boundary points and the substructure boundary points can be determined. These boundary point coordinates are then replaced with the node indices of their respective bridge components, and the parameters from the boundary condition dictionary are written sequentially into the boundary condition module of the overall model file.

[0171] Sixthly, the material data of the bridge components are written into the material module of the overall model file to obtain the format file of the bridge FEM model.

[0172] Since material property parameters are typically not explicitly defined in bridge BIM models, this embodiment of the invention pre-defines a set of material parameter values ​​for bridge components, such as aggregate and concrete. Furthermore, these material parameter values ​​are also directly written into the material module of the overall model file as pre-defined material properties.

[0173] Therefore, by following the six steps outlined above, the corresponding data is written into the node module, section definition module, line component module, coupling constraint module, boundary condition module, and material module of the overall model file, thus completing the process of filling the overall model file. The overall model file is specifically a .txt file, which is the format file for the bridge FEM model and can be directly read and analyzed by the finite element system.

[0174] In this embodiment of the invention, by writing each JSON file and preset material data into a specific module of the overall model file, the conversion of intermediate file data to the finite element system import module is realized, thereby establishing a standardized conversion process for intermediate file data to bridge FEM models.

[0175] In one possible implementation, after generating the format file of the bridge FEM model, the format file of the bridge FEM model is then imported into the finite element system for analysis to obtain the bridge FEM model.

[0176] The complete model file, containing data from various JSON files and preset material data, can be directly imported into the finite element system for analysis. The finite element system can parse and visualize the imported file, generating a corresponding bridge FEM model. The rendered bridge FEM model can be viewed as follows: Figure 9 As shown. Through the automatic query function in the finite element system, the bridge FEM model can be queried to find that it contains 132 coupling constraints, 3 fixed supports, 2 unidirectional movable supports, 384 nodes, and 260 line components.

[0177] In this embodiment of the invention, the generated bridge FEM model format file is directly input into the finite element system, establishing an automatic input interface for importing and analyzing from the file into the finite element system, thus forming a complete conversion process from importing the bridge BIM model to exporting the bridge FEM model.

[0178] In summary, this embodiment of the invention first exports IFC data from the bridge BIM model, achieving separation of data and model, and avoiding secondary development using the BIM software's programming interface to extract the underlying data of the BIM model. Furthermore, the exported IFC data is directly processed, and various JSON files are constructed and stored according to data type, then integrated to form the bridge FEM model format file. This achieves automatic and rapid conversion from bridge BIM model to FEM model solely at the data processing level. The conversion process is directly applicable to various bridge BIM models, demonstrating strong versatility. Moreover, it eliminates the need for targeted construction of the BIM model and the addition of information required for finite element analysis, improving model conversion efficiency and thus enhancing the efficiency of bridge design work.

[0179] The method for converting a bridge BIM model into a bridge FEM model provided by this invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for converting a bridge BIM model into a bridge FEM model, characterized in that, include: Export IFC data from bridge BIM model; Based on the IFC data, the cross-sectional features of bridge components are extracted, the cross-sectional geometric parameters are determined based on the cross-sectional features, and dissimilar cross-sections are selected. The cross-sectional geometric parameters are stored as component information files, and the cross-sectional geometric parameters of the dissimilar cross-sections are stored as cross-sectional information files. Based on the component information file, a connection relationship file storing the connection relationship between adjacent bridge components, a boundary condition file storing the overall boundary of the bridge, and a node information file storing the coordinates of the centroid points corresponding to the bridge components are constructed respectively. The component information file, the cross-section information file, the connection relationship file, the boundary condition file, and the node information file are converted to obtain the format file of the bridge FEM model; The format file of the bridge FEM model is obtained through format conversion in the following way: Read the coordinates of the centroid points corresponding to the bridge components stored in the node information file, and write the node module of the overall model file after assigning a node index to each centroid point coordinate. Write the cross-sectional geometric parameters of the distinct cross-sections stored in the cross-sectional information file into the cross-sectional definition module of the overall model file; The bridge components are identified by reading the component information file, and the corresponding section number of the bridge component is retrieved from the section information file. Associate the node index of the bridge component with the section number, and write the associated line component parameters into the line component module of the overall model file; The coordinates of the master node and slave node corresponding to the bridge component matched in the connection relationship file are replaced with the node index of the bridge component and then written into the coupling constraint module of the overall model file. The coordinates of the upper structure boundary points and the lower structure boundary points stored in the boundary condition file are replaced with the node indexes of the bridge components and then written into the boundary condition module of the overall model file. The material data of the bridge components are written into the material module of the overall model file to obtain the format file of the bridge FEM model.

2. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The process of exporting IFC data from the bridge BIM model includes: Export the bridge BIM model as an IFC model; Geometric information and attribute semantic information of bridge components under different component types are extracted from the IFC model; When the bridge component has a global identifier, the global identifier is formatted and standardized, and the geometric information and attribute semantic information of the bridge component are associated with the global identifier after format standardization. When the bridge component lacks a global identifier, a global identifier for the bridge component is generated, and the geometric information and attribute semantic information of the bridge component are associated with the generated component identifier. Geometric information with global identifiers is stored as IFC data in GLB format.

3. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The step of extracting the cross-sectional features of bridge components based on the IFC data includes: The triangular facet data of each bridge component is obtained by parsing the IFC data; The extension direction vector and length of the bridge component are calculated based on the triangular facet data to determine the cut-off position of the cross section, and the cross section geometry data corresponding to each cut-off position is extracted. A pre-constructed bridge section template database is obtained, and the bridge section template database is retrieved based on the cross-sectional geometric data to obtain the cross-sectional features of the bridge components. The bridge section template database stores the cross-sectional features of the corresponding cross-sectional types under various component types of bridge components.

4. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The process of determining the cross-sectional geometric parameters and filtering out dissimilar cross-sections based on the cross-sectional features includes: The type identifier index, number of inner and outer contour points, and two-dimensional coordinates of the inner and outer contour points of the bridge component corresponding to the cross-sectional features are obtained from the cross-sectional features. The cross-sectional geometric parameters of the cross section are calculated by calling the calculation function according to the type identifier index. The calculation function is used to calculate the cross-sectional geometric parameters of the cross section based on the number of inner and outer contour points and the two-dimensional coordinates of the inner and outer contour points. Cross sections with different geometric parameters are selected from the cross sections as distinct cross sections.

5. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The connection relationship file is constructed in the following way: Parse the cross-sectional geometric parameters in the component information file to obtain the centroid coordinates of the corresponding cross-section of each bridge component; When adjacent bridge components are of the same type, the endpoint coordinates of the adjacent bridge components are determined as the matching master node coordinates and slave node coordinates; When adjacent bridge components are of different component types, the master and slave node components are determined according to the connection relationship of the bridge components, and the centroid coordinates of the master bridge component in the master and slave node components are determined. For each of the main bridge components, calculate the spatial distance between the centroid coordinates of the main bridge component and the centroid coordinates of the secondary bridge components in the main-secondary node components; The coordinates of the centroid point corresponding to the closest spatially distant secondary bridge component and the centroid point coordinates of the primary bridge component are determined as the matching secondary node coordinates and primary node coordinates. Store the matching master node coordinates, slave node coordinates, and the corresponding bridge component type name as a connection relationship file.

6. The method for converting a bridge BIM model into a bridge FEM model according to claim 5, characterized in that, The step of storing the matched master node coordinates, slave node coordinates, and corresponding bridge component type names as a connection relationship file includes: The target database is queried based on the component type name of the matched bridge component to obtain the corresponding type identifier index. The target database stores semantic information about the connection relationship of bridge components. Based on the type identifier index, the corresponding number of coupled degrees of freedom and the coupled degrees of freedom index are obtained by querying the target database. Obtain a preset coupling constraint template, and write the corresponding master node coordinates, slave node coordinates, number of coupling degrees of freedom, and coupling degree of freedom index of the matched bridge components into the coupling constraint template to obtain a coupling constraint dictionary; The coupling constraint dictionary is stored as a connection relationship file.

7. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The boundary condition file is constructed in the following manner: Parse the cross-sectional geometric parameters in the component information file to obtain the centroid coordinates of the corresponding cross-section of each bridge component; Determine the sequence of centroid points of the main girder of the bridge in the extension direction of the bridge components, and take the centroid points at the beginning and end of the centroid point sequence as the boundary points of the superstructure. Identify the bridge abutment structure and select the centroid of the bottom section of the bridge component in the abutment structure as the boundary point of the substructure. The coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, the component type names of the bridge components corresponding to the upper structure boundary points, and the component type names of the bridge components corresponding to the lower structure boundary points are stored as boundary condition files.

8. The method for converting a bridge BIM model into a bridge FEM model according to claim 7, characterized in that, The step of storing the coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, the component type name of the bridge component corresponding to the upper structure boundary points, and the component type name of the bridge component corresponding to the lower structure boundary points as a boundary condition file includes: The target database is queried based on the component type name of the bridge component corresponding to the boundary point of the superstructure and the component type name of the bridge component corresponding to the boundary point of the substructure to obtain the type identifier index of the corresponding component type name. The target database stores the semantic information of the bridge boundary conditions. Based on the type identifier index, query the degree of freedom constraints of the upper structure boundary points and the lower structure boundary points from the target database; Obtain a preset boundary condition template, and write the coordinates of the upper structure boundary points, the coordinates of the lower structure boundary points, and the degree of freedom constraints into the boundary condition template to obtain a boundary condition dictionary; Store the boundary condition dictionary as a connection relationship file.

9. The method for converting a bridge BIM model into a bridge FEM model according to claim 1, characterized in that, The method further includes: The bridge FEM model file is imported into the finite element system for analysis to obtain the bridge FEM model.

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