Structural design and fabrication of concrete reinforcement with layout optimisation and robotic filament winding

Reinforced concrete is a major contributor to the environmental impact of the construction industry, due not only to its cement content, but also its steel tensile reinforcement, estimated to represent around 40% of the material embodied carbon. Reinforcement has a significant contribution because of construction rationalisation, resulting in regular cages of steel bars, despite the availability of structural-optimisation algorithms and additive-manufacturing technologies. This paper fuses computational design and digital fabrication, to optimise the reinforcement layout of concrete structures, by designing with constrained layout optimisation of strut- and-tie models where the ties are produced with robotic filament winding. The methodology is presented, implemented in open-source code, and illustrated on beam and plate reinforcement applications. The numerical studies yield a discussion about parameter selection and constraint influence on material and construction efficiency trade-offs. Small-scale physical prototypes up to 50 cm x 50 cm provide a proof-of-concept.