A model for design/construction integration during the initial phases of design for building construction projects

Current problems in the construction industry are forcing a reevaluation of the fragmented approach of design-bid-build. Design/construction integration is cited as a means to improve project performance, but there is now only limited understanding of why or how to formally incorporate construction into the design process and there are no performance indicators to measure the actual degree of integration, and the cost, schedule, or quality improvements. The objective of this exploratory research was to provide new understanding to help bridge the existing gap between designers and constructors by investigating the initial design process from both designers' and constructors' viewpoints, developing a model of the integrated design/construction processes that operate during the initial design phases of building construction projects, and providing a conceptual framework for integration that highlights implementation requirements, and how the design process and the roles of owners, designers and constructors change under an integrated approach. The study included interviews with personnel from owner, design, and construction organizations in selected building construction projects that had construction input during the project's early phases of design. It focused on architectural design, project planning, estimating and scheduling, and definition of building systems and construction methods. The main contributions of this investigation are that it increases our understanding of the initial design phases of building construction projects, provides a comprehensive description of current design/construction integration practices in the United States, and builds a state-of-the-art model of design/construction integration that regards integration as a total system. The model requires integration to be another project objective and describes planning for integration; establishes design-freeze milestones; differentiates horizontal from vertical integration; and contains special processes that help bridge the gap between design and construction activities. The major implications of the model are an identification of prerequisites for integration, a description of an integrated process for the early design phases in a building construction project, and a definition of the characteristics of the project team members to support and implement integration.