Multiple work zone strategy for repetitive on-site work of modular construction using parallel station method

Abstract

Modular construction offers benefits such as high quality, low cost, and short durations owing to the high productivity of repetitive production. To maximize productivity, modular construction involves repetitive schedules; however, the scheduling methods exhibit limitations when applied to on-site work. These methods are optimized by adjusting the production rate of activities; however, the bounds of the production rates of modular construction on-site work are limited because of workspace limitations in the units and varying amounts of work between activities. This results in idling time in the scheduling methods. Thus, in this research, the parallel station method (PSM) was employed to ensure a flexible production rate. A discrete event simulation model was developed and employed to estimate the number of workers and work duration. The results demonstrated the following: 1) The developed scheduling method exhibits better results than the method for stick-built construction. 2) When applying the PSM, the line-of-balance method is cost-effective, while the TACT method is time-effective, implying that scheduling methods should be selected based on the primary objectives of modular projects. The findings of this research will contribute toward improving the accuracy and applicability of repetitive scheduling methods and reduce the labor cost and duration of on-site work.