Sustainability analyses of embodied carbon and construction cost in high-rise buildings using different materials and structural forms

Understanding the impact of material choices and structural forms on the embodied carbon and construction cost in high-rise buildings is important to improve building designs with regard to sustainability. The objective of this study is to investigate the impact of the choice of construction materials and structural forms on the embodied carbon and construction cost of high-rise buildings. The results show that high-rise buildings using structural steel have the highest construction cost at 4575 HK$/m2 and the most embodied carbon at 760 kg CO2-e/m2, respectively. Using reinforced concrete for high-rise buildings reduces 30% of the embodied carbon (to 4194 HK$/m2) and 7% of the construction cost (to 537 kg CO2-e/m2). High-rise buildings using composite materials have the lowest construction cost (3740 HK$/m2), but produce slightly more embodied carbon (557 kg CO2-e/m2) than concrete buildings. For a specific structural form, the construction cost and the embodied carbon as a function of the building height follow concave upward trends, indicating that each structure has a suggested height with relatively lower cost and carbon content, e.g. 50–70 storeys for composite core-outrigger structure at around 3700–3900 HK$/m2. Similarly, the suggested height for composite tube-in-tube structure is 60–80 storeys at 3900–4100 HK$/m2, whereas braced-tube structure has a suggested height of 60–80 storeys at 3500–3600 HK$/m2.