Uncertainty-aware linear schedule optimization: A space-time constraint-satisfaction approach

Schedules and physical workspaces are two key elements of linear construction projects that are extremely interdependent. Any negligence in incorporating spatial and temporal constraints in developing and improving schedules of linear projects results in inevitable delays and workspace congestions and can substantially hinder the performance of the activity resources. This study augments the current linear scheduling methods by presenting an uncertainty-aware optimization framework to optimize the duration of linear projects while minimizing their potential congestions. The methodology is built upon the new concept of space-time float for explicit consideration of spatio-temporal constraints of activities and their inherent uncertainty. A constraint satisfaction approach was used for the two-tier optimization of duration and congestion. A fuzzy inference system was also incorporated to assess the inherent uncertainty in the schedule. Two case examples from literature are analyzed. The results demonstrate the effectiveness of the proposed method in planning and control of the unforeseen variations from planned schedules of linear projects.