Mixed-Integer Linear Programming Approach for Scheduling Repetitive Projects with Time-Cost Trade-Off Consideration

This paper studies a repetitive project scheduling problem considering multiple crews and fixed logic with the objective to minimize the total cost without exceeding a given deadline. Multiple crews means that an activity can be performed simultaneously in several units by hiring additional crews, whereas fixed logic indicates that for each activity the units assigned to the same crew must be performed by a fixed construction sequence. Existing research works use heuristic methods to solve the problem without formulating an explicit model for further analysis. In this paper, we adopt the mixed-integer programming approach to construct an exact model. To handle large-size problems, an approximate model with reduced number of constraints and variables is further presented. Extensive computational experiments demonstrate that the exact model is capable of finding optimal solutions for medium-size problems in a reasonable amount of time, and the approximate model produces good feasible solutions for large-size problems in an accepted length of time. (C) 2016 American Society of Civil Engineers.