The embodied energy of a building is not only but essentially due to the quantity of material in its structure. Current fabrication techniques of optimised reinforced concrete (RC) structural elements have not proved sufficient economic competitiveness to be broadly accepted by the construction industry. This partly explains why the construction industry has not yet been able to reduce the embodied energy of newly-constructed buildings or civil works. However, most of the researches driven in the academic world on digital fabrication with concrete are focused on the construction of non-standard structures. Application of digital fabrication to standard structures could help bridge the gap between the need for lower-carbon structures and the economic interest of players in the construction industry. This paper questions the compatibility of existing building codes with digital manufacturing techniques and presents a novel method for the fabrication of sustainable optimised reinforced concrete beams, compliant with EN 1992-1-1 design requirements.