Sustainability assessment for construction projects: A cost-sustainability tradeoff approach

Organizations are facing demands from their regulators, clients, and society to embrace sustainable practices in their projects so that the project when executed is not only beneficial for the economy of the organization but is also beneficial for the environment as well as for the society. As projects are made up of activities, therefore consideration of sustainability at the activities' definition stage leads to a sustainable project. Activities vary from project to project, and various levels of complexities are involved hence a comprehensive methodology for sustainability measurement at the project activities level has largely been absent from the literature. This paper has addressed this problem by presenting a fuzzy approach for the construction phase sustainability assessment of projects, based on environmental and social dimensions, through its activities using the fuzzy inference system (FIS) and fuzzy analytical hierarchal process (FAHP). A four-tier sustainability hierarchal model has been developed. FAHP has been applied to tiers 1 and 2 whereas FIS has been used for effectiveness index determination of sustainability indicators at tier 0. An example construction project from the real world has been used to show the usefulness of the approach. One global criterion, two secondary criteria, 4 primary criteria, and 9 effective indicators have been selected with expert opinion at tier 3, 2, 1, and 0 respectively. The results show higher sustainability can be achieved with a higher cost and that multimodal project activities can provide a sustainability-cost tradeoff to the decision-maker. This approach will help project managers and construction professionals to define and assess the activities of a project based on sustainability performance in addition to costs.