Constructability assessment model for commercial building designs in the United States

At the early design stage of construction projects, designers often rely on rules of thumb to make critical decisions about the geometry, construction systems, and materials of their designs without evaluating construction requirements and constraints. The ease of building, or constructability, is a critical factor that should be examined at the early stage of construction projects when the design is the most amenable to change. The motivation for this study is the current demand for skilled workers and the lack of a quantitative constructability model for commercial construction projects in the United States. To meet these needs, this paper investigates constructability factors and their relative importance in the selection of the most constructible building systems using a multicriteria technique, the analytic hierarchy process. Through a comprehensive literature review, 79 constructability attributes are identified, and based on 298 responses received from a questionnaire survey, the attributes are categorized into six factors. Then using pairwise comparisons between constructability factors and common building systems in the United States, knowledge from construction experts is obtained and a constructability assessment model is developed. The main contribution of this research to the body of knowledge is to develop constructability indexes for building components and their construction systems and to formulate a model for measuring the constructability of commercial building designs. Using the proposed constructability assessment model, designers can identify the trade-offs between the constructability of their design alternatives and make informed decisions.