# The Standardization Method and Application of the BIM Model for Interchanges
## 5 Creation of a BIM Component Library for Interchanges
### The Process of Creating a Component Library  
The BIM component library integrates the results of interchange BIM component standardization, facilitates the invocation of interchange standardized BIM components, enables digital delivery of the results, and is an important resource and tool for interchange BIM forward design work. As a complex project, the interchange contains a wide range of disciplines and therefore a wide variety of BIM components. First, scientific and reasonable classification of interchange BIM components is required, followed by the production of BIM components according to the model level, and finally, a strict audit. Thus, it can be concluded that the process of creating the interchange BIM component library should include five steps: overall planning, standard determination, component production, component audit, and component library application [31], as shown in Figure 4.  
General Planning  
As an important part of highway engineering, the interchange has the characteristics of wide topography and many professions involved in highway engineering. BIM component library should be created firstly by the appointed party and the appointed party to submit the project information requirements, carry out a project information seminar, and  
Figure 4: The process of creating interchange BIM libraries.  
determine the BIM components needed in the library and the specifications to be met after the overall planning of the project, to facilitate the comprehensiveness and standardization of the content of the BIM component library later.  
2. Standard determination  
The content and format of BIM components need to be standardized to facilitate the effective management of BIM components at a later stage. To improve the efficiency of management at a later stage, the BIM components of different projects, sections, and stages of interchanges need to be classified and coded in a standardized way. To improve the standardization of model creation, it is necessary to determine whether the depth of the model meets the requirements.  
3. Component fabrication  
The BIM model should be created in the appropriate BIM software platform, and the geometric and non-geometric information should be added to the BIM model according to the research results of the coding and information depth levels applied at different stages.  
4. Component audit  
The content of the composition audit includes three aspects: content audit, accuracy audit, and specification audit. The audit shall be jointly participated by the appointing party and the appointed party, and each party shall assign experienced professionals to check. The components that pass the audit shall be synchronized in the component library for retrieval and download; the audit results and modification opinions shall be given if they do not pass the audit, and the appointed party shall modify and add geometric and non-geometric information of the model according to the opinions. After completing the modification, submit the component again for review until the component passes the review.  
5. Component library applications  
The component library application includes two aspects: management and maintenance. Management means that the interchange BIM component library should be applied during the whole life cycle of design, construction, operation, and maintenance. As the project phase progresses, the management can submit the component library replenishment requirements to the appointed party and re-enter the component production and component review process at different decision points to improve the component library according to the project requirements. During the application period, the component library should be maintained and updated in real-time to meet the requirement of timeliness in the standardization work.