Comparative study of discrete-event simulation and system dynamics for construction process planning

Discrete-Event Simulation (DES) has been the mainstream in the area of construction simulation. Recently, research (Pena-Mora and Park 2001, Lee et al. 2003) has shown the possibility of applying System Dynamics (SD) to the construction management discipline. Unlike DES, which is based on statistical analysis and queuing theory, SD is able to represent the complex system of construction management through capturing feedback effects, managerial actions, and soft variables such as schedule pressure and morale, which are important in determining project behavior. Though SD is capable of representing such variables and relationships, the validity of SD models has often been questioned because when modeling with SD, it is difficult to attain as much detail as when modeling with DES. Therefore, SD has not been fully adopted to simulations in the area of construction management, despite its advantages. To gain widespread use in the construction management area, SD needs to address operational details. In this paper, an SD based earthmoving process model is presented to explore ways in which operation details can be represented using SD. Initially, an SD based earthmoving model is proposed and for the purpose of comparison, and is tested against a DES counterpart model, created using STROBOSCOPE (Martinez et al. 1994). The tests have shown that the simulation results generated by the SD model are as accurate and reliable as those of the STROBOSCOPE models. The specifics of this comparison are identified, including how the SD model is created from and compared to DES model at an operational level. These research findings support the widespread use of SD in the area of construction management; thus, aiding in the representation of the complexities inherent in construction.