A linguistic group decision-making framework for bid evaluation in mega public projects considering carbon dioxide emissions reduction

Green construction is to conserve the resources and reduce the negative impact of construction activities on the environment to the maximum extent, with scientific management and technological progress under the premise of ensuring the quality, safety and other basic requirements. Recent years, accompanied by the rapid development of construction industry, a considerable proportion of energy and resources, particularly high-carbon materials, is consumed in the construction activities, emitting mass greenhouse gases, which have a damaging impact on the environment. This is especially for the mega public projects. Therefore, under the green and sustainable perspective, actions to control carbon dioxide (CO₂) emissions in the construction industry are imperative. In this case, if CO₂ emissions reduction can be considered beforehand during the bid evaluation stage, contractors will be guided by bid evaluation indicators and therefore improve their construction schemes, enabling the construction phase to be green, energy saving and sustainable. This is because bid evaluation indicators can serve as guiding effect on the contractors. Given that CO₂ emissions are rarely given sufficient consideration in traditional bid evaluation, this study conducts a systematic analysis to identify major sources of CO₂ in construction phase and attempts to develop a conceptual computational model in terms of CO₂ emission. Then, a linguistic group decision-making framework for bid evaluation in mega public projects considering CO₂ emissions reduction is developed. In this framework, entropy, relative entropy, the standard deviation method and weighted aggregation operators are applied to determine the indicator weights, the expert weights and the information aggregation in bid evaluation decision-making. Finally, a scenario comparison between the proposed linguistic group decision-making bid evaluation framework and the traditional framework is made through a case study, and the scientific basis and reliability of this new framework are validated. The establishment of this framework can enrich the decision-making methods in construction management field. And it can provide meaningful reference for owners to choose the most qualified contractors and spur contractors to improve their construction schemes, enabling construction phase to be green, energy saving and sustainable.