Work-Package Planning and Schedule Optimization for Projects with Evolving Constraints

Abstract

Planning and scheduling are challenging processes, particularly for projects with continuously evolving requirements and constraints such as design-build and turnkey projects. In the literature, schedule optimization models can only handle predefined activities and fixed constraints. To better support dynamic projects, this paper proposes a flexible constraint programming (CP) framework that optimizes schedules both at the early planning stage and immediately before construction. At the early planning stage, the model selects among alternative network paths and construction methods to determine the most suitable work packages for the project. Later as more constraints become refined, the optimization model helps to meet the persistent milestones, deadlines, and resource limits, using a variety of activity-crashing strategies without changing the committed construction methods. Experimenting with a case study proved the flexibility of the model, its unique support for planning, and its ability to consider evolving project constraints. The proposed model contributes to developing automated decision support systems for cost effectively meeting the evolving schedule constraints.