Sustainable design model to reduce environmental impact of building construction with composite structures

Thanks to advances in technologies related to zero energy buildings, reducing CO₂ emissions during the design and construction phase becomes more and more important to reduce environmental impact from building construction. Even though more than half of high-rise buildings over 200 m completed in 2014 employed steel reinforced concrete (SRC) composite structures, most of sustainable design to reduce CO₂ emissions were limited to reinforced concrete (RC) buildings. Since SRC is a composite structure consisting of three component materials of concrete, steel shape, and rebar, CO₂ emissions can be effectively reduced by applying eco-friendly design strategies for determining the proportions of those components in SRC members. In this study, the sustainable design model for SRC composite structures is developed for optimal combination of construction materials with minimized CO₂ emissions. The model is used to provide comprehensive analyses of variability of CO₂ emissions in the building construction. The results indicates that increasing the cross-sectional area of steel shape is more advantageous for reduction of CO₂ emissions than increasing the cross-sectional area of concrete for composite structures subjected to high axial loads required in high-rise building constructions based on the analysis of the contribution of each component to strength of column. Sensitivity analysis reveals that the environmental impact can be significantly reduced by using high strength materials in SRC structures. Further, through the application of the model to the design of an actual high-rise building, it is confirmed that derived SRC columns have excellent performances in terms of environmental impact and space utilization.