A flexible scheduling framework for repetitive construction projects based on constraint programming

Scheduling repetitive construction projects (RCPs) is a challenging task due to the nature of the activities involved. It requires careful consideration of both flexibility and computational performance. This paper develops a versatile RCP scheduling framework applicable to multiple construction scenarios, providing greater flexibility than existing models. The framework incorporates various scheduling features for repetitive activities, such as soft logic, multiskilled crews, multimode execution, crew transfers, and continuous or noncontinuous execution. It also offers optional optimization objectives, such as minimizing the overall project duration, total cost, crew interruption time, and number of employed crews. Planners can combine the features of repetitive activities and choose one or more objectives to meet their needs and preferences. The proposed framework is based on constraint programming, which balances computational efficiency and solution quality while remaining user-friendly. The practicality and effectiveness of the framework are verified through three case studies involving five real-life projects. The results demonstrate that the proposed framework can produce RCP schedules with shorter duration, lower costs, or reduced resource utilization compared with those generated by existing models.