Arranging Weekly Work Plans in Concrete Element Prefabrication Using Genetic Algorithms

Chien-Ho Ko1 & Shu-Fan Wang2

1Assistant Professor, Department of Civil Engineering, National Pingtung University of Science and Technology, 1, Shuefu Rd., Neipu, Pingtung 912, Taiwan, e-mail:, phone: +886-8-7703202, fax: +886-8-7740122; Research Director, Taiwan Lean Construction Institute; Executive Director, Lean Construction Institute Asia
2Assistant Researcher, Taiwan Lean Construction Institute


Applying lean production concepts to precast fabrication have been proven promising. However, foreman encounters difficulties in arranging weekly work plans. The objective of this research is to overcome the difficulty when arranging weekly work plans in concrete element prefabrication. Current practices in arranging weekly work plans are fairly basic, and depending heavily on experience, thereby resulting in inefficient resource utilization and even late delivery. To enhance weekly work planning, this research develops a flowshop sequencing model. In the model, production constraints and buffer sizes between stations are considered. A multi-objective genetic algorithm is then used to search for optimum solutions with minimum makespan and tardiness penalties. The performance of the proposed method is validated by using two case studies. The experimental results show that the research work can be used to enhance weekly work planning especially for numerous combinations of sequences.


precast fabrication, weekly work plan, genetic algorithms, flowshop sequencing model, buffer



Ko, C. & Wang, S. 2008, 'Arranging Weekly Work Plans in Concrete Element Prefabrication Using Genetic Algorithms' In:, Tzortzopoulos, P. & Kagioglou, M., 16th Annual Conference of the International Group for Lean Construction. Manchester, UK, 16-18 Jul 2008. pp 849-856

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