Improved critical chain project management framework for scheduling construction projects

Construction projects are subject to a wide range of constraints, such as project complexity, resource scarcity, and duration uncertainty. The critical chain project management (CCPM) has emerged as a method for construction scheduling. This paper proposes an improved CCPM framework to enhance the implementation of CCPM in construction project management practices. The framework addresses two major challenges in CCPM-based construction scheduling, including buffer sizing and multiple resources leveling. Buffers play a key role in ensuring successful schedule management. However, buffers generated by the existing sizing methods are either unnecessarily large, which wastes resources, or insufficiently robust against various uncertainties. Resource leveling is another critical challenge in CCPM-based construction scheduling because it requires a fundamentally different approach from the resource leveling used in traditional scheduling methods. The proposed framework improves buffer sizing by integrating into the buffer sizing process various uncertainties that affect construction scheduling but are not factored in by current practice. These uncertainties are assessed in five dimensions with their respective metrics developed in the framework. Furthermore, the framework explores the feasibility of multiple resources leveling in CCPM-based construction scheduling, with a novel method that manages the trade-offs between activity duration and resource usages based on a multimodal activity execution structure. Three case studies were undertaken in this paper. The results showed that the proposed framework outperformed existing buffer sizing methods by generating buffers with reasonable sizes and sufficient robustness against uncertainties. The results also proved the feasibility and effectiveness of performing multiple resources leveling in CCPM-based construction scheduling.