Multiobjective optimization in Linear Repetitive Project scheduling

The Critical Path Method (CPM) and the Repetitive Scheduling Method (RSM) are the most often used tools for the planning, scheduling and control Linear Repetitive Projects (LRPs). CPM focuses mostly on project’s duration and critical activities, while RSM focuses on resource continuity. In this paper we present a linear programming approach to address the multi objective nature of decisions construction managers face in scheduling LRPs. The Multi Objective Linear Programming model (MOLP-LRP) is a parametric model that can optimize a schedule in terms of duration, work-breaks, unit completion time and respective costs, while at the same time the LP range sensitivity analysis can provide useful information regarding cost tradeoffs between delay, work-break and unit delivery costs. MOLPS-LRP can generate alternative schedules based on the relative magnitude and importance of different cost elements. In this sense it provides managers with the capability to consider alternative schedules besides those defined by minimum duration (CPM) or minimum resource workbreaks (RSM). Demonstrative results and analysis are provided through a well known in the literature case study example.