The Pfalzturm is currently still just a vision: very soon, however, this 41-metre-high, rotationally symmetrical landmark – featuring a spiral staircase and four viewing platforms – is set to become a reality, offering unique views over the Palatinate Forest. In Paris, the project team is now presenting the most striking part of the structure – the spire – on a scale of 1:2, and is looking forward to welcoming many curious visitors.

This ambitious design concept incorporates two structural innovations. Firstly, acetylated beech laminated veneer lumber is used for the struts – a world first. This wood-based material, newly developed by the t-lab research division in collaboration with industry partners, is as strong as native beech and can be used permanently outdoors. Acetylation makes the wood resistant to wood-destroying fungi, ensures it retains its shape and maintains its strength – regardless of weather conditions – and does so without the use of toxic additives, making it fully recyclable. Until now, such viewing towers were mostly made of steel or concrete. This innovative material also opens up numerous new possibilities for the use of solid timber in outdoor applications.

The second innovation comes from Saxony! The delicate structure of the Pfalz Tower’s double-curved lattice shell is joined using 3D-printed stainless steel nodes. The internal support structure and the 3D printing process for the stainless steel nodes were developed by the Laser Institute at Mittweida University of Applied Sciences in collaboration with the FLEX research group at HTWK Leipzig. Since 2018, the two partners have been conducting research within the Saxony5 technology transfer network into a digitally based technology concept for large-format 3D printing in steel, thereby carrying out pioneering work. What makes the customised steel node elements special is, on the one hand, the ‘Macro-SLM’ manufacturing process developed at the Laser Institute of Mittweida University of Applied Sciences, which is based on the principle of ‘Selective Laser Melting (SLM)’ and can reduce unit costs by up to 90 per cent. The key to this is a generative node design, which derives the shape of the connecting elements from the geometry of the connected bars and generates a fill structure consisting of ‘continuous surfaces’, enabling continuity in the printing process. “The Pfalzturm project impressively demonstrates that 3D-printed elements are not only of interest for steel construction but also offer options for timber construction,” says Stahr. 

The researchers from Kaiserslautern, Mittweida and Leipzig aim to demonstrate in Paris both how they are addressing sustainability challenges in timber construction and the possibilities offered by automated manufacturing in the field of 3D printing. “The Pfalzturm project combines both aspects and thus represents a major innovation: By combining material innovation and architectural precision in the field of modern digital design processes with precise prefabrication, new horizons are opening up for timber construction too,” says Marius Zwigart, deputy head of the HTWK’s FLEX research group.