Robust Construction Scheduling Using Discrete-Event Simulation

In construction management the definition of a robust schedule is often more important than finding an optimal process sequence for the construction activities. In nearly every construction project the planned schedule must be continually adapted due to disruptions like activities take longer than expected, construction equipments have failures, resources vary, delivery dates change or new activities have to be considered. Therefore, it is imperative to generate a robust schedule regarding the different project objectives like time, costs or quality. In the context of planning and scheduling the term “robust” means that normal project variations have no significant effects on the schedule and mandatory project objectives. One appropriate concept to analyze the robustness of schedules is to simulate different typical disturbance scenarios. In the end, from the multitude of valid schedules the one that is nearly optimal and highly robust is selected for execution. In this paper a concept is presented to generate robust construction schedules using evolution strategies. Therefore, it is necessary to define reasonable robustness criteria to evaluate the schedules. Two important robustness criteria are presented in the paper. Finally, the practicality of the presented robust scheduling approach is validated by a case study.