Design for Assembly (DFA) Evaluation Method for Prefabricated Buildings

The Design for Assembly (DFA) method, incorporating lean and prefabricated construction concepts, is emerging as a novel approach to industrialize the construction industry. In recent years, several countries have developed guidance documents to enhance building assembly efficiency and quality through the implementation of DFA methods. However, there remains significant room for improvement in the assembly efficiency of prefabricated buildings, along with a lack of effective evaluation measures. Therefore, this paper aims to develop a DFA evaluation method specifically applicable to prefabricated buildings, utilizing the formula design, Delphi method, and Analytic Hierarchy Process (AHP) method. The DFA evaluation method presented in this study comprises two main components: the assembly efficiency index (AEI) and the assembly design index (ADI). The assembly efficiency evaluation serves to gauge the efficiency level of a construction system and identify the space for improvement. On the other hand, the assembly design evaluation identifies factors influencing assembly, enabling process enhancement and upgrading. Subsequently, the paper employs the developed evaluation method to analyze a case, the New Lawuga School in Yushu, China. The AEI of the New Lawuga School is 2.44 m³/pc., and the ADI value of the building is 0.54. The assembly evaluation of the New Lawuga School reveals that efficient assembly was achieved through integrated design and parts reduction. However, non-standardized design emerged as a hindrance to the assembly process. The primary contribution of this study lies in the proposed DFA evaluation method tailored specifically for prefabricated buildings.

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