Ontology-Based Design Features for Representing Constructability in Architectural Design: Toward BIM in Off-Site Construction

To enable off-site construction (OSC), architects must finalize construction details in their design deliverables as early as possible, particularly in a building information modeling (BIM) environment, to enhance design constructability and project efficiency. However, most architects lack construction knowledge and practical experience, which impedes their ability to incorporate design-specific construction input (i.e., manufacturing, logistics, assembly, and installation demands) into BIM processes at the early stages. This deficiency can lead to errors, rework, and ultimately increased construction costs. To address this challenge, this study introduces an innovative approach to incorporate constructability knowledge into architectural design processes for BIM-enabled OSC projects. The methodology involved retrospective case studies of two completed OSC projects utilizing a component-centric analysis framework. This analysis resulted in an ontology of construction-specific design features that identified 11 types of constructability issues and the characterization of nine design feature classes that were categorized into three groups: substance; intersection; and composition. These feature classes and their 29 attributes were rigorously characterized from the perspective of BIM-enabled architectural design. This feature-based approach not only extends the BIM vocabulary and semantics from an architectural standpoint but also encapsulates construction knowledge as an integral input to architectural design. Additionally, three strategies were identified, analyzed, and summarized to inform these design features and attributes and to evaluate their effectiveness of addressing constructability issues. The study’s ontological approach assists architects in acquiring a comprehensive understanding of design-specific construction knowledge, enabling them to differentiate, locate, and integrate critical types of constructability information into BIM-enabled architectural design deliverables early in the project delivery process. This paper is a foundational step in the development of automated modeling, algorithms, and constructability assessment for BIM-enabled architectural design deliverables, aimed at achieving a more streamlined construction process.