Reinforced concrete column design for minimal embodied carbon emissions

• Main Author: Siddiq Amsyar Bin Shalan
• Other Authors: Teoh Bak Koon
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Civil engineering::Structures and design; Engineering::Materials
• Online Access: https://hdl.handle.net/10356/163371
• Institution: Nanyang Technological University

The construction industry is under considerable legislative pressure to reduce its carbon emissions, with it being one of the most energy intensive industries which relies heavily on raw material extraction. Although there are efforts that have been put into practise to minimize embodied carbon emissions, more can be done to further curtail carbon emissions in a systematic way that could guide structural engineers in their daily design tasks. Therefore, this paper explores the potential in design optimization of reinforced concrete column to achieve minimal embodied carbon emissions. This enables reduction of irreversible carbon emissions from early design stages, in particular during the product stage of a building life cycle. In this study, total embodied carbon generated by stocky columns undergoing two different types of failure (i.e., pure axial failure and balanced failure condition) were calculated by varying several column design parameters such as concrete strengths, rebar ratio as well as applied loadings and moments. The results suggest that under both failure conditions, minimal embodied carbon emissions can be established when a combination of minimum steel reinforcement and higher concrete strengths are used. Moreover, the trends and results showed that employing these combinations can reduce emissions effectively based on design assumptions that was predefined. This paper also proves that columns should be arranged, where possible, in a way that does not induce large un-balanced moments thus columns designed to resist purely axial loading emits lesser embodied carbon. However, contrary to columns under balanced condition, columns resisting purely axial loads requires higher concrete strength contribution when minimum steel reinforcement is provided, hence greater concrete volume is required to resist the same load and as such this solution may not be the most material efficient or aesthetically desirable. As such, this will pose a greater challenge for the relevant stakeholders to prioritise between maximising embodied carbon efficiency and material efficiency. Therefore, project managers, structural engineers, and architects should practise due diligence in being aware of the environmental implications of their design considerations.