The purpose of this paper is to identify optimum crew formations at unit execution level of repetitive projects that minimize project duration, project cost, crew work interruptions and interruption costs, simultaneously.
The model consists of four modules. The first module quantifies uncertainties associated with the crew productivity rate and quantity of work using the fuzzy set theory. The second module identifies feasible boundaries for activity relaxation. The third module computes direct cost, indirect cost and interruption costs, including idle crew cost as well as mobilization and demobilization costs. The fourth module identifies near-optimum crew formation using a newly developed multi-objective optimization model.
The developed model was able to provide improvements of 0.2, 16.86 and 12.98% for minimization of project cost, crew work interruptions and interruption costs from US$1,505,960, 8.3 days and US$8,300, as recently reported in the literature, to US$1,502,979, 6.9 days and US$7,222, respectively, without impacting the optimized project duration.
The novelty of this paper lies in its activity-relaxation free float that considers the effect of postponing early finish dates of repetitive activities on crew work interruptions. The introduced new float allows for calculating the required crew productivity rate that minimizes crew work interruptions without delaying successor activities and without impacting the optimized project duration. It safeguards against assignment of unnecessary costly resources.
Funding: The authors would like to acknowledge the financial supports from the Natural Sciences and Engineering Research Council of Canada (NSERC) Engage (Grants N01729 and N00807) and Gina Cody School of Engineering and Computer Science, Concordia University (Grant VE0010).
Arabpour Roghabadi, M. and Moselhi, O. (2021), "Optimized crew selection for scheduling of repetitive projects", Engineering, Construction and Architectural Management, Vol. 28 No. 6, pp. 1517-1540. https://doi.org/10.1108/ECAM-10-2019-0590
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