Pioneers in 3D Printing: ETH Zurich Uses 3D Sand Printing For Real-Scale Architectural Project

3D concrete printing is currently experiencing a great boom in architecture. Whole houses are already being printed layer by layer. For the Smart Slab project, on the other hand, researchers use 3D printing to produce the formworks for the building elements in order to be more efficient.

Header Picture: ETH Zürich/ Tom Mundy

Researchers from ETH Zurich produced an 80 m² lightweight concrete floor slab as part of the DFAB House. This is the world’s first real-scale architectural project using 3D sand printing for the formwork.

Smart Slab is the name of the ceiling developed by the group of Benjamin Dillenburger, Assistant Professor for Digital Building Technologies at ETH Zurich. And the name says it all: The slab combines the structural strength of concrete with the design freedom of 3D printing. At the thinnest points, the ceiling is just 20 millimeters thick, decoratively ribbed and not half as heavy as a conventional concrete ceiling.

Combining Innovations From Architecture, Construction and Energy

Smart Slab is one of the core elements of the residential unit DFAB House, which is a joint research project of the Swiss National Centre of Competence in Research (NCCR). It combines innovations from the fields of architecture, construction and energy. The 80 m², 15 tonne ceiling consists of eleven concrete segments and connects the lower floor with the two-storey timber structure above.

The lightweight construction was made possible by 3D sand printing to create the underlying formwork for the ceiling. In 3D printing, highly complex structures are as easy to create as a solid block – meaning that foreign material can be cut from a design before it is sent to the printer.

For the fabrication of the formwork elements, Dillenburgers research group developed a new planning software. This software is able to record and coordinate all relevant parameters for production. In addition to basic data such as room dimensions, the researchers also entered a millimeter-precise scan of the curved wall, which acts as the main girder of the concrete ceiling. With the help of the software, the geometry of the slab was adapted so that only as much concrete as statically necessary is delivered to each point according to the force curve.

More Precision Than With Analog Planning

„We didn’t draw the slab, we programmed it,“

says Mania Aghaei Meibodi, senior researcher and Smart Slab project manager at Dillenburger’s group.

„With analog planning, it would never be possible to coordinate all these aspects with each other, especially not with such precision.”

Once planning is complete on the computer, the manufacturing data can be exported at the push of a button to the machines on which Smart Slab cooperates with several industrial partners.

The individual concrete segments were ready for transport after two weeks of hardening. Thanks to precise planning and prefabrication, time on site was reduced to a minimum.

„It was overwhelming to see how seamlessly our elements were joined together on site and to the existing components of the DFAB House,“

says Dillenburger.

„We also owe this to the great interdisciplinary cooperation with our partners. The meticulous work we put into the planning has paid off in full.“

What are your thoughts on the project? In which areas of architecture do you see further potential for 3D printing?