Digital fabrication of ribbed concrete shells using automated robotic concrete spraying

Mishael Nuh, Robin Oval, John Orr, Paul Shepherd

Research output: Contribution to journalArticlepeer-review

10 Citations (SciVal)


Doubly-curved ribbed concrete shells are a materially efficient means of spanning large areas such as roofs and floors. However, the fabrication of such structures poses challenges in terms of formwork manufacturing as well as material deposition. This has led to their decline compared to more prismatic shapes such as flat slabs which can be manufactured more economically. This paper presents a novel fabrication process called Automated Robotic Concrete Spraying (ARCS) by which glass fibre reinforced concrete (GFRC) is sprayed onto a curved formwork to create thin shell components of variable thickness. The trajectory planning and generation algorithm developed and implemented in ARCS to create such components is presented. Two sets of prototype shells were fabricated: one which forms the segments of a larger structural floor demonstrator and another consisting of a single component with deep ribs on a thin shell. The sequencing used to generate the spray paths for each component is outlined, with each prototype using two different strategies to add ribs onto the fabricated shells. While the fabrication process has been used in conjunction with a pin-bed mould actuating flexible formwork to create the spraying surface, the trajectory planning approach is adaptable enough such that any formwork can be utilised. Combined with the output speed of material deposition, ARCS offers the potential to enable mass production and customisation of doubly-curved ribbed structural concrete shells of variable thickness as an industrial process at an architectural scale.
Original languageEnglish
Article number103159
JournalAdditive Manufacturing
Issue numberPart B
Early online date26 Sept 2022
Publication statusPublished - 30 Nov 2022

Bibliographical note

The work presented in this paper was part of the ACORN research project funded by UK Research and Innovation (EP/S031316/1). Additional funding was provided by the Cambridge Commonwealth European and International Trust. The authors would like to acknowledge and thank the contributions of NRFIS staff Ricardo Osuna-Perdomo, Diana Thomas-McEwen, Pieter Desnerck, Martin Touhey, and Phil McLaren who aided in the fabrication of the prototypes, Thibault Schwartz for his support on the HAL Robotics Framework, and Richard Lavery for his support on the Power-Sprays spraying station.


  • Building construction
  • Digital concrete
  • Material jetting
  • Shotcrete
  • Trajectory planning

ASJC Scopus subject areas

  • Biomedical Engineering
  • Materials Science(all)
  • Engineering (miscellaneous)
  • Industrial and Manufacturing Engineering


Dive into the research topics of 'Digital fabrication of ribbed concrete shells using automated robotic concrete spraying'. Together they form a unique fingerprint.

Cite this