If you walk along the Oudezijds Achterburgwal canal in Amsterdam, you will notice an elegant and aesthetically pleasing steel bridge for pedestrians. If not for the media attention it got, you would even consider it a regular feature of the city's architecture. But this bridge loaded with sensors, is actually the world's first 3D-printed steel bridge, according to an Imperial College London press release.
Printed by four robots in a matter of just six months, the bridge heralds a new beginning in additive manufacturing. Most 3D printing projects, whether they are designed for outer space or rapid infrastructure, use proprietary inks or starting material. This bridge, however, uses steel, a tried and tested construction material, and is actually an experiment to test whether it can find applications in 3D printing.
"A 3D-printed metal structure large and strong enough to handle pedestrian traffic has never been constructed before," said Imperial co-contributor Prof. Leroy Gardner of the Department of Civil and Environmental Engineering, in a press release. "We have tested and simulated the structure and its components throughout the printing process and upon its completion, and it’s fantastic to see it finally open to the public."
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The project, initiated in 2015, used multi-axis robots to heat the steel to 2,732°F (1,500°C) and constructed the bridge layer by layer. The almost 40-foot (12-meter)-long bridge is made up of close to 10,000 pounds (4,500 kg) of stainless steel. Considering the way the bridge was constructed, it was only befitting that a robot was actually used to inaugurate it. Dutch Queen Maxima pressed a green button to set a robotic arm equipped with a pair of scissors into motion to cut the ribbon and opened the bridge to pedestrians and cyclists.
The bridge is also equipped with multiple sensors that will collect data about strain and vibration as people use it under various weather conditions. This data will then be fed into a 'digital' replica of the bridge that will help researchers better understand how 3D-printed steel behaves over a period of time. It will also help them identify areas that might require maintenance or modifications and utilize this information for larger construction projects.
The project was completed by the collaborative efforts of MX3D, a Dutch startup focusing on 3D metal printing, researchers at Imperial College London, and The Alan Turing Institute.
"3D printing is poised to become a major technology in engineering and we need to develop appropriate approaches for testing and monitoring to realize its full potential," said Professor Mark Gilorami, from the Turing Institute, who led the project.
The 3D-printed bridge is scheduled to stay there for a period of two years, while the original bridge is being renovated.