Towards a Lean-Oriented Multi-Mode Resource-Constrained Project Scheduling Problem with Activity Crashing and Preemption: A Real-Case Study

Integrating lean principles into the multi-mode resource-constrained project scheduling problem (MRCPSP) provides a structured approach to eliminate waste of resources. This study introduces a tri-objective mixed-integer linear programming (MILP) model for an extended MRCPSP variant (LMRCPSP) aimed at minimizing project makespan, total cost, and waste of resources (WoR) including both renewable and non-renewable types while ensuring compliance with minimum quality standards. The model incorporates preemptive and crashable activities to improve scheduling flexibility. It also includes rework after activity execution to ensure project quality meets or exceeds the minimum acceptable standard. A real-world construction case study validates the proposed approach, and the AUGMECON2 algorithm is employed to generate Pareto-optimal solutions and explore trade-offs among objectives. A comparative analysis with Microsoft Project schedules, along with sensitivity analyses, further demonstrates the impact of excluding key contributions, confirming that neglecting preemption, rework, or waste reduction leads to higher costs, longer durations, and reduced quality. This underscores the practical value of the proposed framework. Finally, the conclusion and further directions are provided.