Pioneering Work: 3D Printed Office Building

3D printing offers several advantages, providing it is technically and financially feasible: The maximum printing speed of the BOD2 gantry printer used in Hausleiten is one metre per second and significantly reduces the construction time. This means that the shell of the building in Hausleiten will be completed in around 45 hours printing time only. 3D printing also offers new design possibilities compared to traditional concrete construction, such as architecturally appealing rounded shapes.

“Currently, 3D printing is only applicable for construction projects up to a certain size, which is why well-trained skilled employees remain crucial for the successful realisation of construction projects,“ emphasises Thomas Birtel, CEO of STRABAG SE: “The prevailing massive shortage of skilled labour will continue to accompany us in the future, and we have to compensate for this with two strategies. By investing in training, e.g. with our new STRABAG Camp[us] Ybbs, as well as by increasing productivity with new technologies.“

PERI is using the COBOD BOD2 gantry printer for the project in Hausleiten. This printing technology comes from COBOD, a Danish manufacturer in which PERI has been a shareholder since 2018. In this technique, the print head moves along three axes on a firmly installed metal frame. The advantage:  The printer can move to any position within the truss structure and only needs to be calibrated once. The 3D printer applies the printing material (dry mortar) in layers, thereby creating walls. By producing two parallel printed structures, a hollow wall is created which is back-filled with in-situ concrete and acts as a static load-bearing system. For the outer wall, another external wall is printed to create a cavity which is then filled with thermal insulation material. The printed walls can be seen as a kind of “lost formwork“.

During the printing process, the printer already incorporates the lines and connections that will be laid for water, electricity, etc. into the design. The BOD2 has been certified in such a way that work can be carried out in the printing area during the printing process. In this way, manual work, such as laying empty conduits and connections, can be easily integrated into the printing process.

The material for printing is stored in silos. After adding water, the ready-to-use dry mortar is pumped directly into the print head. For the office building in Hausleiten, material of the brand “Tector Print“ was used, which was developed by Holcim and specially adapted to the specific requirements of 3D concrete printing.