GRC 2023
Mishael Nuh, Robin Oval, John Orr & Paul Shepherd
Curved compressive vaulted structures, such as arches and shells, presents a materially efficient means of spanning large distances using brittle material. Historically, when material costs were high and labour costs were low, this was a cost-efficient construction practice and form for concrete. As labour costs increased, concrete forms moved towards simpler prismatic shapes which require less complex falsework and formwork. With a pressing need to reduce the embodied carbon of our built environment, there is a growing interest in revisiting these curved forms to save material and carbon. This presentation presents a digital fabrication method called Automated Robotic Concrete Spraying (ARCS) which sprays glass fibre reinforced concrete (GFRC) onto an actuated pin-bed mould to enable a cost-efficient and automated means of manufacturing curved concrete shells. An overview of the physical setup as well as the trajectory planning approach is presented. Using the system, two sets of prototypes are created: a large nine-segment shell demonstrator which acts as a thin shell flooring system and a deeply-ribbed concrete shell. A 3D scan analysis of the prototypes shows that the process can be used to accurately fabricate variable thickness and curved concrete shells. This fabrication process was found to be both robust and accurate and offers the potential to facilitate the mass production of concrete shells on an industrial scale.
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