Time, Cost, and Environmental Impact Analysis on Construction Operation Optimization Using Genetic Algorithms

Abstract

Environmentally conscious construction has become a subject of research during the last decades. Even though construction literature involves plenty of studies that emphasize the importance of environmental impact during the construction phase, most of the previous studies failed to combine environmental analysis with other project performance criteria in construction. To achieve environmentally conscious construction and successfully manage a complex construction environment, multiple project objectives and their relationships need to be considered. In this study, the authors propose a framework on the basis of the concept of control accounts to determine optimal construction operations when project time, cost, and environment impact (TCEI) are considered as project objectives during project planning. The framework also supports decision-making by using sensitivity analysis. Life cycle assessment is applied to the evaluation of environmental impact in terms of global warming potential (GWP). The nondominated sorting genetic algorithm II, or NSGA-II, is selected for implementation in MATLAB to determine optimal construction operations. A case study is used to illustrate the application of the framework. It is shown by the case study that the application of the genetic algorithm to search problems, such as the case study, is promising in terms of determining optimal solutions, but computation speed can be an issue, if it involves a large set of data. In addition, data collection and processing is a major challenge, especially the processing of environmental impact data. Tools are needed to facilitate data collection and processing. Currently, the proposed framework includes a critical path method, on the basis of fixed logical relationships among activities, to determine the duration of a project. The effect of resource and other constraints on such logical relationships, and potentially the duration of a project, is not addressed in this study.