Measuring Risk-associated Activity's Duration: A Fuzzy Set Theory Application

Uncertainty is inherent in the construction projects. Appropriately determining a project schedule under uncertainty is one of the most important factors for a contractor's success in a project. However, when the likelihood of incurring risk events and the riskassociated consequences are uncertain, contractors often face difficulties in estimating project duration. While the Critical Path Method (CPM) has been widely used in scheduling a project, it has been frequently criticized because it assumes an activity's duration deterministic without reflecting uncertainty involved in a project schedule. The Program Evaluation and Review Technique (PERT) and the Monte Carlo Simulation (MCS) technique have been used to reinforce the shortcomings of the CPM through applying probabilistic analysis approach. They, however, still impose a problem of identifying probabilities under the circumstances where schedule variables cannot be defined as probabilistic nature. The main objective of this paper is to present an alternative schedule risk quantification method based on the fuzzy set theory for estimating a risk-associated activity's duration. A hypothetical case study is prepared to show how the proposed method can be put into practice. Interviews with industry experts are also held to verify the usability as well as to identify the pros and cons of the method.