Integrating quality and safety in construction scheduling time-cost trade-off model

Quality and safety are important and are the leading concerns in a construction project. Planning a project without properly incorporating these two performance parameters propagates multifarious defects and accidents in construction projects and this ultimately leads to cost overrun and time delay. In order to deal with quality and safety at the planning stage (along with time and cost), a decision-making model considering time, cost, quality, and safety (TCQS) is developed on the basis of a many-objective evolutionary algorithm (nondominated sorting genetic algorithm III) and presented in this study. An example is illustrated to demonstrate the capabilities of the proposed model for generating and visualizing the optimal trade-off among TCQS. The proposed model shows better results compared to earlier reported scheduling models. Additionally, the study has also conducted a correlation analysis to identify the interrelationship, if any, among the TCQS components. Furthermore, the solution obtained from the model was put through sensitivity analysis. The developed model was also checked for two large-scale scheduling cases and found to work efficiently. The inclusion of objectives like quality and safety will provide a holistic scheduling model for the construction professionals. This study is expected to provide an alternative planning strategy and assist project managers in selecting optimal TCQS trade-offs while constructing a facility.