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Tectonics in 3D Concrete Printing

Andrea Zambotti

Published Apr 14, 2021

Tectonics

Tectonics in architecture is defined as “the science or art of construction, both in relation to use and artistic design  (Maulden, R.). Therefore, the term tectonics is obviously closely related to the English words technique, technology and construction.

Introduction

3d concrete printing (3DCP) is considered by many as the technology that will revolutionize the built environment.  The introduction of new degrees of freedom for architecture, sustainability, customization and increased productivity are just some of the potentials of this technology.   However, this revolution does not affect merely construction methods, but also the design process. Indeed, together with its advantages, there are also limitations in 3DCP, such as cantilevering and dimensions. Hence, while in a traditional approach technology works in support of design, with 3DCP the same design needs to be based on the technology. In other words, the tectonics of the object should be coherent in all phases of the process. “Concrete structures are tectonic when the material and technique have a significant impact on the initial idea about form, in such a way that the final structure can be said to be a consequence of material and technique.” (Ole Egholm Pedersen). To better explain the strong relation between design, material and technology, I would like to illustrate the personal experiment of a 3DCP chair.

Limitations of the Technology

Contrary to traditional design, with 3DCP the shape of objects is strongly influenced by the material and the technology applied. The combination of these two does not allow, for example, the creation of a cantilever. Therefore, to print objects that exceed a maximum printable angle, it is necessary to use support material. Moreover, due to the mechanical properties of concrete during the printing phase, it is not even possible to create precise 90° angles. For this reason, models should only include angles with a minimum radius of 5cm.  The last limitation encountered during the chair experiment was the inability to get smooth edges. Indeed, since 3DCP is based on the overlapping of different layers, the result is often an irregular boundary surface.  This aspect was particularly important, considering that the chair was designed as different panels to be assembled together.

Design Process

Once the limitations were cleared, it was possible to proceed to the design phase.  To avoid cantilevers, the design of the chair was sliced in 7 different layers, later connected using a central rubber tube.  Every layer consists of 4 panels printed horizontally.  The side layers are bigger and stable, whereas the inner layers are smaller and can slightly rotate thanks to the central connection.  Secondly, all the angles of the object were rounded to make them printable. Since the minimum radius is 5cm, the geometry of the smaller panels was changed to accommodate this feature.  In conclusion, the geometry of each panel was simplified to get straight paths during the printing phase.  Indeed, straight lines result into a smoother and more regular edge, necessary to achieve a stable assembly.

Conclusion

Traditional ways of approaching design do not necessarily include limitations derived by the particular building technology.  Indeed, the variety and progress of the state-of-the-art technologies applied in the built environment enables engineers and architects to realize extraordinary structures.  However, with 3DCP this approach is not possible.  The technology developed so far presents many limitations.  My 3DCP chair better exemplifies the strong relation between design, technique, technology and construction. Only a coherent process may enhance the potentials of 3DCP.

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Figure 1: Irregularity of the Edge Surface

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Figure 2: Assembly of the 3DCP Chair

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