Micro-motion level simulation for efficiency analysis and duration estimation of manual operations

Due to the labour-intensiveness of the construction industry, accurate estimation of cycle time of manual activities is essential for reliable planning and scheduling of operations. Labour productivity study is used in current practice to obtain the required cycle time of manual tasks. However, the reliability of labour productivity study in estimating durations of manual activities is inhibited by its dependence on various factors which change with the different working conditions of construction jobsites and the difficulties associated with measuring productivity. This study thus investigates the use of a predetermined motion time system (PMTS) for modelling manual construction operations for cycle time estimation and efficiency evaluation. A motion-level simulation approach is developed by integrating PMTS into discrete-event simulation (DES) modelling, providing an automated and simple-to-use method of analysing manual tasks. As a case study, manual construction operations from a construction jobsite with different levels of repetitiveness are modelled, and the actual and simulated cycle times are compared and analysed. The results confirm the effectiveness of a PMTS-based simulation approach to modelling manual construction operations and its reliability in estimating the duration of manual tasks.