Decision support for prefabrication strategy selection on building systems

The rapid growth in sustainable construction and improvements in technology presents many opportunities for incorporating prefabrication in green buildings. However, the value of prefabrication is often limited when its benefits are not well understood by a project team and prefabrication decisions are not made early in the design phase. Existing decision-making tools for prefabrication are focused on project level decisions vs. system-level optimization and are intended to be used by contractors instead of designers or project teams. To help project teams make more informed prefabrication decisions on a system level, this research identified a list of generic prefabrication opportunities and tactics and developed a dynamic programming based decision-making and analytical tool: Prefabrication Strategy Selection Methodology (PSSM). The term “prefabrication strategy” indicates a system-level action plan which involves many prefabrication-related decisions during each phase of the system’s delivery. These decisions should be carefully coordinated since many of them are interrelated and can have a significant impact on one another. PSSM evaluates and determines prefabrication strategies according to their impact on the overall project goals regarding the initial cost, schedule, quality, and sustainability. This research examined three types of building systems: wood framing systems, curtain wall systems, and mechanical systems. The predefined list of opportunities and tactics as well as the framework of PSSM were validated on nine case study projects. Preliminary observations and recommendations on the use of prefabrication among the three trades were collected from field visits for future study.