IFC-Based Framework to Move beyond Individual Building Elements toward Configuring a Higher Level of Prefabrication

Prefabrication is a form of industrialization that transfers some stages of the construction project from fields to an off-site production facility. The most widely used form of prefabrication in construction is the use of prefabricated individual building elements in which a particular part or form is repeated many times. However, the benefits to the construction project may be increased by moving beyond prefabrication of individual building elements toward configuring a higher level of prefabrication. In this paper, an industry foundation class (IFC)–based system is developed to configure groupings of precast elements for a prefabricated building to minimize the total number of components so as to reduce the production, transportation, and installation cost. The framework uses three-dimensional computer-aided design (3D CAD) software that is compatible with IFC. Geometrical and topological relationships of elements are extracted from IFC and modeled as a graph data model (GDM). The system performs analysis on the graph model based on the attributes of the building elements to generate all possible configurations for precasting. Constructability rules are applied to reduce the solutions to feasible configurations. The functionality of the developed framework is verified by considering an illustrative example of a residential building. Results showed that applying the new configurations of precast components can contribute up to 15% reduction in the total cost compared with the traditional elemental approach.