World's first 3D-printed steel footbridge opens

The world's first 3D-printed steel structure, dubbed a 'living laboratory' bridge because of its digital twin and co-developed by Imperial College London, has been opened to the public in Amsterdam.

Dutch company MX3D took four years to develop the 12m-long bridge. It took four robots six months to print the structure, using 4,500kg of steel and 1,100km of wire. It was installed over the Oudezijds Achterburgwal canal in Amsterdam's Red Light District and formally unveiled on 15 July.

A network of installed sensors on the bridge will feed data to Imperial College London researchers, allowing them to measure, monitor and analyse the performance of the structure as it handles pedestrian traffic.

The data collected will enable researchers and engineers to measure the bridge's 'health' in real-time, monitor how it changes over its lifespan and understand how the public interacts with 3D-printed infrastructure.

The data will also be used to create a digital twin of the bridge. The performance and behaviour of the physical bridge will be tested against the twin, which will help answer questions about the long-term behaviour of 3D-printed steel, as well as its use in real-world settings and in future construction projects.

To get from the conceptual stage to the installed footbridge, the Steel Structures Research Group at Imperial College London conducted the underpinning research and validation, including testing destructive forces on printed elements, advanced digital twin computer simulations, non-destructive real-world testing on the footbridge and the development of an advanced sensor network to monitor the bridge's behaviour over its life.

Imperial College London co-contributor Professor Leroy Gardner of the Department of Civil and Environmental Engineering said: "A 3D-printed metal structure large and strong enough to handle pedestrian traffic has never been constructed before. We have tested and simulated the structure and its components throughout the printing process and upon its completion, and its fantastic to see it finally open to the public."

Imperial College London co-contributor Dr Craig Buchanan said: "We look forward to continuing this work as the project transitions from underpinning research to investigating the long-term behaviour of metal printed structures. Research into this new technology for the construction industry has huge potential in for the future, in terms of aesthetics and highly optimised and efficient design, with reduced material usage. It has been fascinating and we are delighted that the structure is now ready to be used."

The testing work was led by Professor Gardner and Dr Buchanan, supported by a team of undergraduate and postgraduate students, PhD candidates, post-doctoral researchers and laboratory technicians.

In the absence of structural design provisions for 3D-printed steel, physical testing and computer simulation is important for ensuring the safety of new 3D-printed structures. Imperial College London's Steel Structures Research Group undertook a research programme using small-scale destructive material and cross-section testing, computer modelling and large-scale non-destructive real-world testing on the footbridge.

Professor Gardner said: “3D printing presents tremendous opportunities to the construction industry, enabling far greater freedom in terms of material properties and shapes. This freedom also brings a range of challenges and will require structural engineers to think in new ways.” 

Dr Buchanan said: “For more than four years, we have been working from the micrometre scale, studying the printed microstructure up to the metre scale, with load testing on the completed bridge. This challenging work has been carried out in our testing laboratories at Imperial College London, and during the construction process on site in Amsterdam and Enschede, the Netherlands, on the actual printed bridge.” 

The Imperial College London researchers are part of a wider team of structural engineers, mathematicians, computer scientists and statisticians working on The Alan Turing Institute-Lloyd’s Register Foundation programme in data-centric engineering. The programme is led by Professor Mark Girolami at The Alan Turing Institute and previously of Imperial College London’s Department of Mathematics.

Professor Girolami said: “3D printing is poised to become a major technology in engineering, and we need to develop appropriate approaches for testing and monitoring to realise its full potential. When we couple 3D printing with digital twin technology, we can then accelerate the infrastructure design process, ensuring that we design optimal and efficient structures with respect to environmental impact, architectural freedom and manufacturing costs.” 

The data captured from the bridge will be made available to other researchers worldwide who want to work with the Turing researchers in analysing the data.

The team’s work was predominantly funded by The Alan Turing Institute, with additional funding from the Engineering and Physical Sciences Research Council, part of UK Research and Innovation.

This article originally appeared on BIM+
Image source: MX3D

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