The world’s first 3D printed reinforced, pre-pressed concrete bridge has been commissioned in Gemert, a small town in north Brabant province in The Netherlands.
Work started on the eight-metre long cycle bridge in June this year and the construction was lowered into position in few weeks ago. It’s now part of a new section of ring road around the town.
The bridge, printed in 1cm layers of concrete, is a joint effort between students at Eindhoven University of Technology and BAM Infra, a construction company that is using innovative techniques.
One of the advantages of printing a 3D bridge is that much less concrete is needed than in the conventional technique in which a mold is filled. By contrast, a printer deposits only the concrete where it is needed. This has benefits since in the production of cement a lot of CO2 is released and much less of this is needed for printed concrete. Another benefit lies in freedom of form: the printer can make any desired shape, and no wooden molding frames are needed.
The team also printed the steel reinforcement at the same time as the concrete section. While laying a strip of concrete the concrete printer adds a steel cable, making the bridge ‘pre-stressed’ so that no tensile stress can occur in the concrete.