ABSTRACT
Decisions made during the early stages of building design play a pivotal role in determining its environmental impact. However, designers often face numerous choices at these stages and typically lack a clear understanding of which decisions most significantly influence a building’s carbon footprint. Consequently, many critical decisions are deferred to later stages of the design process. Life-cycle assessment (LCA) offers a powerful tool for improving early-stage decision-making by providing insights into the environmental impacts of different design choices. This study proposes a methodology for integrating LCA into early-stage design processes to evaluate the environmental friendliness of structural design codes. Specifically, the study compares the embodied carbon associated with reinforced concrete (RC) beams designed according to two widely used design codes: ACI 318 - 19 and Eurocode 2. Sensitivity analysis is employed to extend the findings across various design parameters for both codes.
The results show that RC beams designed using ACI 318 achieved, on average, a 25% reduction in embodied carbon, with reductions varying from 16% to 40% based on specific design parameters, in comparison to those designed under Eurocode 2. This advantage is attributed to the ACI code’s more flexible design philosophy, which allows for optimization of section dimensions based on reinforcement ratio and b/d ratio. Designs adopting the maximum allowable reinforcement ratio under ACI 318 typically result in the smallest cross-sectional dimensions, leading to more efficient and environmentally favorable outcomes. These findings underscore the potential of informed code selection in improving the structural efficiency and reducing the environmental impact of structural designs.
