A CPM-based scheduling method for construction projects with fuzzy sets and fuzzy operations

The Critical Path Method (CPM), which is used to schedule construction activities that depend on one another through network relationships, is deterministic with regard to the duration assigned to the execution of the activities and the results produced in certain values. Unfortunately, construction activities are performed under uncertain conditions. Project risks cause variations in activity duration, and in turn the entire network is affected by uncertainty. In this context, activity duration can be represented by fuzzy sets, and CPM network calculations can be performed by fuzzy operations through a method developed in this study. Since the duration of activities is represented by fuzzy sets, and network calculations can be performed by fuzzy operations, the activity early/late start/finish times and the project completion time are calculated as fuzzy sets by the proposed method. An example CPM application with fuzzy sets is also presented in the paper. The findings show that CPM is applicable with fuzzy sets, and the developed method operates well for modelling the uncertainty in CPM calculations.