Improved workflow for precast element design based on BIM and lean construction

Prefabricated concrete has substantial merits regarding a cleaner environment and less rework. However, precast concrete design suffers from an inefficient workflow. In this research, a new workflow is proposed by combining lean construction (LC) and Building Information Modeling (BIM) based on the plan-do-check-act (PDCA) framework. First, the current state value stream is built to obtain the root causes of waste. Second, an automatic precast element design engine (APEDE), including parametric BIM libraries, precast element design tool, and link for BIM model and precast element design tool, is developed to facilitate the precast design process. Finally, future state maps are introduced, with key LC principles and APEDE implemented in three case studies. Results show that the time efficiency and total man-hours are improved by more than 68.75% and 5.95 h, respectively. The proposed framework could improve efficiency and enhance the interaction and collaboration between fabricators and engineers.