System Dynamics Approach for Investigating the Risk Effects on Schedule Delay in Infrastructure Projects

Effective risk management is critical to the success of infrastructure projects. Although several studies in the literature have focused on various aspects of infrastructure project risk management, limited efforts have investigated the overall dynamics of infrastructure project risks and how dynamic risk interactions can affect a project schedule. This study, therefore, takes a holistic view to investigate the effects of dynamic risk interactions on a schedule delay in infrastructure projects. First, major risks that can cause a schedule delay in infrastructure projects are identified through a review of related literature and questionnaire survey. Second, the interactions among main variables related to infrastructure schedule risks are analyzed using causal loop diagrams. Afterward, a system dynamics (SD) model for the investigation of risk effects on a project schedule is developed based on the causal loop diagrams and the underlying relations among the variables. Finally, the model is applied and simulations are carried out. The findings show clearly that dynamic interactions among diverse infrastructure project risks are critical in evaluating risk effects on a schedule delay. Because of the complex and dynamic behavior of the studied system, compared with previous studies in which risk impacts are investigated separately, risk effects on an infrastructure project schedule delay would be larger when major risks are collectively considered. The SD model can be used as a basis for simulating various risk effects on a project schedule to explore the optimum measures to prevent such risks in advance. (C) 2016 American Society of Civil Engineers.