Challenges in designing and fabrication of a thin concrete shell

Complex forms, that in history have always been challenges for architects are now becoming familiar to people working at the edge between architecture and structural design. This is, in particular, true for free form shells design. Before the digital revolution, the shell complexity was statically determined through funicular chains, and physical modelling was an essential part of the design process. Today the growth of computer modelling is accelerating the process. However, fabrication and prototyping are still essential part of the process. The growth of the additive and subtractive manufacturing industry opens new avenues for shell design as the design process can be fine-tuned through the use of Building Information Modelling (BIM), and the manufacturing process can be carried out by robotics. Thereby free flowing shell forms once too complex for traditional construction methods can now be imagined through the additive manufacturing process. This paper, presents the exploration of freeform surface through the use of Rhinoceros and its plug-ins. Three thin concrete shells, namely a continuous, a reticular and a waffle like shell are compared in terms of structural efficiency. Additive manufacturing techniques are explored for their fabrication, with a scaled ABS model produced as proof of concept. The combination of these innovative design and construction techniques aimed to produce a sustainable structure that develops strength through geometry.