A design methodology to reduce the embodied carbon of concrete buildings using thin-shell floors

Abstract

This paper explores the potential of thin concrete shells low-carbon alternatives to oor slabs and beams, which typically make up the majority of structural material in multi-storey buildings. A simple and practical system is proposed, featuring pre-cast textile reinforced concrete shells with a network of prestressed steel tension ties. A non-structural ll is included to provide a level top surface. Building on previous experimental and theoretical work, a complete design methodology is presented. This is then used to explore the structural behaviour of the proposed system, rene its design, and evaluate potential carbon savings.Compared to at slabs of equivalent structural performance, signicant embodied carbon reductions (53-58%) are demonstrated across spans of 6-18 m. Self-weight reductions of 43-53% are also achieved, which would save additional material in columns and foundations. The simplicity of the proposed structure, and conservatism of the design methodology, indicate that further savings could be made with future renements.These results show that considerable embodied carbon reductions are possible through innovative structural design, and that thin-shell oors are a practical means of achieving this.

Mud-Concrete Slab System for Sustainable Construction

“…This is specifically noted in terms of embodied energy where the reduced material usage cutting down material related embodied energy by 40%. This strategy of doubly curved concrete shells in modular construction have been previously studies (Hawkins et al, 2020). Current study did not look into optimizing the doubly curved geometry.…”

Automating Concrete Construction: Sustainable social housing in Colombia

“…The approach to reducing the amount of concrete used in buildings is the adoption of non-prismatic concrete elements. Traditional formwork methods for concrete result in building elements with a constant cross-section, but the shear forces and bending moments that such elements have to withstand are far from constant along their length, leading to potential reductions in material use of up to 50% (W. Hawkins et al, 2020;Orr et al, 2011). Current digital design and fabrication methods enable the generation and analysis of customized and complex geometries (Kolarevic, 2004), including non-prismatic concrete elements.…”

“…The second type of concrete elements being studied are floor slabs, in particular, thin concrete shells. Previous research has shown that thin shells can be used for building more sustainable reinforced concrete floor slabs (Hawkins et al, 2020). In this case, the thin shell provides the structural load transfer, whereas a non-structural in-fill provides a level top surface.…”

“…As with non-prismatic beams, the generation module of the software tool is responsible for defining the shape of the slab, particularly focusing on the thin concrete shell that supports it. Departing from the research of Hawkins et. al.…”

“…In terms of minimizing embodied carbon, the use of thin shells for construction of concrete floor slabs by itself has been shown to entail a significant reduction in concrete volume, leading to embodied carbon reductions of more than 50% when compared to flat concrete slabs, as well as self-weight reductions of 43-53%, which would save additional material in columns and foundations (Hawkins et al, 2020). Additionally, we aim to reduce the amount of reinforcement, which, depending on the material, can also have a large impact on the embodied carbon in the slab.…”