Research On Parametric Design And Appication Of Precast Concrete Of A Prefabricated Building Based On BIM Technology

Under the vigorous promotion of relevant national policies,prefabricated buildings are developing rapidly with their advantages of short construction period,low energy consumption and low labor cost.From the perspective of architectural design,BIM-based parametric design of prefabricated buildings realizes the linkage of information models in a three-dimensional form,which not only solves the problems of low modeling efficiency caused by model duplication and economic losses caused by design changes,but also conforms to the development direction of BIM forward design and conforms to the development trend of the integration of building informatization and industrialization.From the perspective of energy conservation and emission reduction,the current calculation of carbon emissions for prefabricated buildings mostly stays in the stage of calculation statistics and empirical calculation.The carbon emissions of prefabricated components can be unified and informationized by model method,which can improve the accuracy rate and provide more choices for design according to the corresponding emission reduction strategy.Therefore,this paper takes the prefabricated shear wall structure as the research object,adopts the parametric design idea,and uses the powerful expansibility of the secondary development of Revit modeling software to propose the parametric model and apply it.The main research work and achievements are as follows :(1)By designing the geometric models of different types of prefabricated components,establishing the logical relationship between the position of the model insertion point and the positioning point,and writing the main program of the two modeling methods of the drive system family and the self-built family,the model is automatically created with the given parameters,and the method of creating the hole is proposed for the multi-hole shear wall.The results show that the parameter linkage model can be modified by parametric modeling,which greatly improves the efficiency.(2)According to the prefabricated building design specification,the reinforcement model of the prefabricated component is established.The Revit API is used to generate the function of the reinforcement and write the reinforcement program to realize the parameters required for the given reinforcement and automatically create the reinforcement.Aiming at the problem that the reinforcement configuration cannot be changed according to the model,a modeling method based on the division of prefabricated shear wall area and the division of edge components is proposed to replace the previous integral modeling,and the adaptive adjustment of the parametric reinforcement model is realized.The model can be shared between different projects by changing the parameters.(3)The user interaction window is designed by WPF,and the visual parameter adjustment interface for modeling and reinforcement of prefabricated components is developed.The creation and modification of the linkage control model are combined with parameter identification.A menu bar that can create different component models is designed to unify the modeling interface and improve the overall design of parametric modeling.(4)Based on the existing parametric model,a program for automatically extracting the quantities of concrete and steel bars is written.By defining the boundary of carbon emission measurement,a carbon emission measurement model is proposed,and a database of carbon emission factors and consumption quota of prefabricated construction projects is established.The Excel file is introduced into the modeling software,and a model-based carbon emission automatic measurement system is developed to automatically calculate the carbon emission of prefabricated components.(5)Combined with an example of a prefabricated shear wall structure construction project,the developed parametric modeling program of prefabricated components is applied to this project.The parameter-driven model verifies the feasibility of the plug-in and the universality of the project,and realizes the visualization of the design process.The carbon emissions of prefabricated components are calculated by parametric model,and the main sources of horizontal and vertical carbon emissions are compared and analyzed.The design direction is guided according to the carbon emission reduction strategy,which provides reference value for parametric design research.