Optimizing the utilization of multiple labor shifts in construction projects

Evening and night shifts are often used in construction projects to accelerate schedules despite their negative impacts on construction cost and productivity. In order to minimize these negative impacts, this paper presents a multi-objective optimization model for scheduling multiple labor shifts in construction projects. The optimization model incorporates (1) an initialization module that initializes the scheduling optimization computations; (2) a scheduling module that develops practical multiple shift schedules and evaluates the impacts of decision variables on project performance; and (3) a multi-objective genetic algorithm module that searches for and identifies optimal/near optimal tradeoffs among minimizing project duration, reducing cost, and minimizing labor utilization in evening and night shifts. An application example is analyzed to illustrate the use of the model and demonstrate its capabilities in optimizing the planning and scheduling of multiple shifts in construction projects while complying with all job logic and labor availability constraints.