Abstract

In 2022, building operations and construction accounted for 37% of total global energy and process related CO2 emissions (UNEP, 2023). Reducing these emissions is urgent. It is therefore worth rethinking the most used building material – concrete.

One approach to lowering the embodied carbon of concrete structures is shape optimisation – using material only where it is needed and taking advantage of the fluidity of concrete to create non-prismatic structural elements (Orr 2012; Orr et al. 2014). Another approach is replacing traditional steel reinforcement by alternative reinforcement, such as WFRP (Wounded-Fibre-Reinforced-Polymer) Bars which show the potential to reduce the embodied carbon compared to their steel-reinforced counterparts (Pavlović et al. 2022; Garg and Shrivastava 2019; Inman et al. 2017).

However, non-prismatic beams and slabs might be more prone to excessive deflection than their prismatic counterparts due to reduced flexural stiffness (Tayfur 2016). Additionally, WFRP -reinforced elements often exhibit greater deflection than steel-reinforced ones, because FRP bars (except carbon FRP ) typically have a lower elastic modulus than steel.

To address this issue, it is necessary to optimise the shape of WFRP - reinforced structural elements for Serviceability Limit State (SLS), ensuring they achieve lower embodied carbon than steel-reinforced ones whilst meeting design requirements for SLS . To achieve this, a theoretical method of shape optimisation for SLS is proposed, demonstrating higher efficiency than the existing method (Tayfur 2016). In addition, a flexural test on three BFRP (basalt FRP ) reinforced concrete slabs was conducted in the NFRIS (National Research Facility for Infrastructure Sensing) laboratory in 2024.

This presentation will cover this experimental study on the deflection of non-prismatic slabs in flexure as well as the theoretical method of shape optimisation for SLS .