About a year ago, the Eindhoven University of Technology (TU/e) introduced a gigantic 3D printer capable of 3D printing concrete. Now, the university has used that 3D printer to begin printing a new concrete pedestrian and bike bridge in collaboration with Netherlands company BAM Infra.
TU/e is calling the bridge the world’s first to be 3D printed from reinforced and prestressed concrete. We actually have seen a 3D printed concrete bridge before; in December, the city of Madrid proudly unveiled what the government proclaimed to be the first bridge of its kind. However, TU/e’s bridge was designed with a special process developed in a research group led by Professor Theo Salet so that each layer is reinforced with steel cables.
“This is exciting to do,” said Salet. “[And] stressful because the work you do is being put into practice for the first time. It must be safe. A lot has been done to investigate how the material behaves and how it will behave if it forms a real construction. So this step, from the laboratory to something that is used in practice, is very beautiful, but also stressful.”
TU/e’s new bridge already looks impressive, and the 3D printing process has just started. When completed, the bridge will be placed in the village of Gemert. In recent months, scale models of the bridge have been constructed and tested for safety, by placing loads of up to 2,000 kg on them. After the scale models performed satisfactorily in the safety tests, the 3D printing was begun; the bridge will be printed in parts which will then be glued together.
That means that there’s very little, if any, waste, making the 3D printing process an advantage both financially and ecologically. Concrete production generates a lot of carbon dioxide, so the less that needs to be used, the better.
“If you pour normal concrete, it runs away on all sides. That is the intention, so that it spreads well in the mold,” Salet explained. “But this is very special material. If I lay it down, it stays in place. Compare it with toothpaste or mayonnaise. It does not lose form.”
“We are committed to the future,” said Marinus Schimmel, Director of BAM Infra Netherlands. “We are constantly looking for a newer, smarter approach to solving infrastructural problems and thus make an important contribution to improving the mobility and the sustainability of our society. Innovation plays a crucial role. With 3D printing we have no auxiliary materials such as formwork required. This produces significantly less waste and we need to use less scarce resources. Also, this approach has a positive effect on the amount of CO2 emitted during the production of the bridge.”
There are other advantages to 3D printing structures such as bridges, as well – there’s much more design freedom, for example, than is available with traditional construction methods, meaning that bridges of unusual architecture can be created. The Netherlands has expressed prior interest in 3D printing for bridges, though other projects seem to have stalled, keeping this new structure a first in the country.
“Thanks to the use of robots, each design repeatedly realized in a unique manner with the same effort,” Salet said of this project. “An important additional advantage is that all the information collected in the design now can be passed directly to the execution. This is an important development in the field of Building Information Management (BIM), because the closer together the parties in the chain. It is ultimately the end user who benefits from this in the form of higher quality and customization.“
According to TU/e, the institution was only the third in the world to begin experimenting with 3D printed concrete, after institutions in the United States and China. The university began developing its giant concrete 3D printer in late 2015, as part of a large-scale research project into 3D printing with concrete. The 3D printed bridge is only the beginning – the research team wants to build structures such as houses with integrated smart components like sensors and more. The project, appropriately dubbed 3D Concrete Printing, is expected to last for several years.
The 3D printed bridge, meanwhile, is expected to be ready in two months and will form part of a roundabout at the Handelseweg Boekelseweg (N605) and the Peeldijk (N272); it is expected to be placed in September 2017 in the Lady Lane Gemert on Peelse Loop. In addition to TU/e, BAM notes BAM Infra work with the following partners: Province of North Brabant, City Gemert-Bakel, Saint-Gobain Weber Beamix BV, Dywidag-Systems International BV, Verhoeven Joinery, NV Bekaert SA, and Witteveen en Bos.
Deputy Christophe van der Maat said, “We challenge from contractors for the construction of new infrastructure for us to pay more attention to sustainability and innovation. By using new materials or by using new technologies. Here we see that the construction industry tackles this challenge with both hands and then you can just give it launched a world first.”
You can see the bridge being 3D printed below in this (Dutch-language) video:
Discuss in the 3D Printed Bridge forum at 3DPB.com.[Sources: TU/e, BAM Infra, NOS, NL Times]