Structural stay-in-place formwork for robotic in situ fabrication of non-standard concrete structures: A real scale architectural demonstrator

Concrete is a highly versatile construction material, not only for the reason that it has excellent properties in terms of structural performance, building physics, availability and price, but also because it can be moulded into virtually any shape regardless of its geometric complexity. However, even though current digital design tools allow to effortlessly design and calculate structures, which are exploiting these properties, this potential remains all too often unrealized. This is due to the fact that geometrically complex concrete structures require expensive, one-of-a kind formwork, which can often not be reused or even recycled. Consequently, the current practice for producing non-standard curvilinear architecture in reinforced concrete is neither ecologically sustainable nor economically feasible for a broader range of architectural typologies. Additive Manufacturing (AM) processes, like 3D printing with concrete, on the other hand, currently struggle with the integration of structural reinforcement, limiting the technique to predominantly compression-loaded applications. This research addresses both issues and proposes Mesh Mould, a robotic fabrication process that unifies concrete formwork and structural reinforcement, and hence potentially reduces formwork waste and construction costs for non-standard reinforced concrete constructions. The development of a fully automated robotic fabrication process involved various research disciplines, including architecture, material science, mechanical engineering, robotics as well as civil engineering. This paper describes the technological developments of the Mesh Mould construction system that were necessary to meet the challenges of 1:1 construction. The results are demonstrated in a final loadbearing structure, the Mesh Mould wall of the DFAB HOUSE on NEST.