چكيده به لاتين
Nowadays, one of the prevailing concerns in projects is the environmental issues and the impact of projects, especially construction projects, on the environment. As a result, there is a significant emphasis on "green" research initiatives. Researchers in the field of construction have been striving to minimize the environmental impact of construction projects by focusing on carbon emissions from transportation, as well as air pollution resulting from the production of raw materials by suppliers. Another area of focus by some authors is the implementation of lean principles in projects. Lean thinking, in particular, aims to reduce waste. Several studies have been conducted on the implementation of lean thinking in construction projects, which have demonstrated that waste in construction projects manifests itself in the form of cost, time, and waste generation. This study presents a comprehensive mathematical modeling of a green and lean construction project. By considering the identified waste types, as described in the literature, two objectives have been pursued: reducing project delivery time and minimizing costs. In addition to environmental protection, this research also addresses waste reduction through the segregation of defective materials and their recycling, along with efforts to minimize transportation. To assess the impact of waste throughout the entire supply chain, different weights have been assigned to various components of the cost objective function. The results of this study indicate that if attention is solely focused on a particular waste type, costs will increase compared to a scenario where equal importance is given to all waste types, resulting in only the cost of that specific waste being minimized. Conversely, assigning equal importance to all waste types yields more favorable outcomes. It is worth noting that expediting project delivery will inevitably incur higher costs. In real-world scenarios, parameters often exhibit uncertainty, and precise values are not available. Therefore, cost parameters such as ordering costs, procurement costs, delay costs, activity durations, inspection durations, and material demands for each activity have been considered as fuzzy numbers. As anticipated, costs under uncertain conditions are generally higher than under certain conditions.
