Dynamic priority rule-based forward-backward heuristic algorithm for resource levelling problem in construction project

Abstract

Resource levelling aims at minimizing the fluctuation of resource usage, which is accomplished by shifting non-critical activities within their float according to some heuristic rules. Most of these rules adopted a unidirectional scheduling based on a static priority rule. In this paper, we propose a dynamic priority rule-based forward-backward heuristic algorithm (FBHA). The FBHA optimizes resource allocation by shifting non-critical activities within their forward free float (FFF), forward total float (FTF) and backward free float (BFF), successively. A project is divided into several phases during each forward/backward scheduling module. In each phase, the shifting sequence and days of non-critical activities depend on a dynamic priority rule set. The FBHA is integrated into the Microsoft Project 2007 commercial software package to improve the performance of the software and facilitate the project planners. One example is analysed to illustrate the iteration process of the proposed FBHA. Another example with multiple precedence constraints is used to demonstrate the effectiveness of the proposed FBHA in complicated construction projects.

Keywords:

• resource levelling
• forward-backward scheduling
• dynamic priority rule
• heuristics
• optimization
• construction project

Acknowledgements

The work described in this article was fully supported by the National Natural Science Foundation of China (Project No. 70871088, 71272146). We are extremely grateful to two anonymous reviewers and the editor of JORS for their constructive comments and suggestions that have been very useful in improving the presented paper.