Sustainable design for reinforced concrete columns through embodied energy and CO₂ emission optimization

This study presents a sustainable design method that optimizes the embodied energy and carbon dioxide (CO₂) emissions of a reinforced concrete (RC) column. Conventionally, the design of RC structures has been focused on the minimization of construction costs while satisfying the structural design code. Recently, however, sustainability aspect in structural design has drawn big attention to structural engineers, especially for structure life cycle assessment. Therefore, it is crucial to understand the relationship between construction costs and consumption of energy including CO₂ emissions, in the design process of RC structures. In the sustainable design process, the objective functions for the cost, embodied energy, and CO₂ emissions were set and numerous optimization analyses for various loading conditions were conducted as the failure mode of RC columns varies according to the eccentricity involving the axial forces and moment. A thorough investigation of the optimization analysis results shows that, when a 10% cost increase is assumed, the embodied energy and CO₂ emissions might undergo an overall reduction of up to 22% and 63%, respectively. As a result, the proposed design method enables the embodied energy and CO₂ emissions to be effectively optimized in the conventional design process of RC columns.