Towards sustainable project scheduling with reducing environmental pollution of projects: fuzzy multi-objective programming approach to a case study of Eastern Iran

Implementation of projects with an acceptable quality level in the minimum cost and time has always been the ultimate goal of managers and decision-makers in the construction industry. On the other hand, the construction industry is responsible for creating various environmental problems. Therefore, reducing the environmental destructive effects of project implementation is of utmost importance. The aim of this paper is to consider the environmental pollution along with the project iron triangle of cost, time, and quality in the scheduling of the construction projects. A multi-objective multi-mode resource-constraint project scheduling model is presented considering the generalized precedence constraints between project activities as well as the limitation of renewable resources and non-renewable resources. In this study, the environmental effects of construction projects as well as the three conflicting goals of cost (budget), time (duration), and quality are taken into account. Also, the limitations of renewable and non-renewable resources as well as the generalized activity precedence relationships are incorporated into the proposed model. The proposed model was implemented on a rural water supply project including 25 activities and was solved using the fuzzy goal programming approach with GAMS software. Different combinations of activity modes were presented along with the start time of each activity considering four objective functions. The results showed that this project would be completed in 190 days, at the cost of $15,394, with the quality level of 0.835, and environmental effects of 0.372, which are between the optimal and worst objective functions values. In addition, the sensitivity analysis indicates the high efficiency of the proposed model and its capability in assisting project managers and planners.