With no formwork required, and customisation costing no more, there could be big time and cost savings on site
Researchers in Switzerland have pioneered a method of 3D printing structural concrete columns at high speed using minimal material and without formwork.
Masters students on the architecture and digital fabrication programme at ETH Zurich developed design software and robotic extrusion techniques to print each of nine unique 2.7m tall columns in less than two and a half hours.
The freeform undulating structures were created with support from the National Centre of Competence in Research into Digital Fabrication for installation at the ‘Concrete Choreography’ dance show at the Origen Festival in Riom.
Each column was printed in multiple thin layers by a specially adapted six-axis manufacturing robot suspended from a gantry. The robot extruded a mix of regular concrete and additives designed to control the material’s behaviour and accelerate the curing time.
Applied commercially, the process would make projects significantly cheaper and quicker, says Dr Benjamin Dillenburger, professor of digital building technologies at ETH Zurich. ‘Our process doesn’t require any formwork, which can account for up to 50% of labour costs in traditional reinforced concrete construction,’ he says. ‘In addition, the customisation of individual elements doesn't add any extra cost and by doing away with material needed for formwork, which custom trades typically dispose of after use, it is a much more sustainable method of construction.’
The process developed by researchers involves the formation of honeycomb-like voids within the structure to help stabilise it while minimising material use. However, on this occasion the voids were subsequently filled in with ordinary concrete, with a reinforcement cage through the centre of the columns, to ensure a strong bond with the printed shell.
‘The software enables us to distribute the concrete exactly where it is needed structurally, which allows us to save a lot of material,’ says Dillenburger. ‘Our vision is to be able to strategically place concrete and not pour massive concrete elements in the conventional way. In theory, the technique could save up to 80% of concrete, compared with conventional construction.’
ETH students were asked to explore how emerging digital technologies could inform the design of a contemporary column order, similar to those devised by ancient Greeks and Romans. The columns had to be visually expressive and form a key element of the stage design at the festival.
The resulting rippled, curvaceous columns are reminiscent of Antoni Gaudi’s work, and Dillenburger believes the famed Spanish architect would have been keen to exploit 3D concrete printing technology were he alive today.
‘Gaudi was very experimental with engineering and state of the art technology, simulating and “form finding” his constructions using advanced physical models. Today’s digital computational design and robots make it possible to build very differentiated and unique architecture, so I think he would be open to the process.’