Scheduling Problem under Constrained Resources: A Historical Review of Solution Methods and Computer Application

Abstract

In construction projects, project execution time is a major concern of the involved stakeholders (client, contractors and consultants). Optimization of project scheduling through time control is considered as a critical factor in project management. Many studies were carried out and many models and software packages were developed since the fifties and till now, but no clear cut methods, to optimize resources while satisfying different constraints were found. The importance of the subject stemmed from the fact that project time completion affects the overall project cost. Considering the most two widely applied scheduling methods: Critical Path method (CPM) and Program Evaluation and Review Technique (PERT), it is found that negligence of handling limitation of resources is evident in most cases. On the other hand, a resource leveling technique which is used to reduce the sharp variations in the resource demand histogram cannot handle the issue of1 minimizing project duration since it is used when there are enough resources. So the leveling process is accomplished by shifting only the non-critical activities within their floats. This paper show a number of heuristics and models to solve scheduling problem of projects subjected to limited resources. Different heuristic methods applied in past studies were examined in order to be tested and applied in a simple example, as a pilot study, so as to be used in real complex projects.