The center of Amsterdam is now home to a nearly 40-foot-long 3D-printed pedestrian bridge that took over four years to complete. It is the first such bridge in the world, setting it up to be a prime example of 3D-printed construction in the future—especially since the bridge is equipped with a network of sensors that will monitor it in real-time.
The bridge opened earlier this month, with Queen Máxima of the Netherlands the first to walk across it.
“A 3D-printed metal structure large and strong enough to handle pedestrian traffic has never been constructed before,” said Leroy Gardner, professor of civil and environmental engineering at Imperial College London and co-contributor on the project. “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.”
Being the first such bridge, there were no structural designs or blueprints to pull from. Instead, researchers relied on physical testing and computer simulations to ensure the safety of the 3D printed structures.
In the lab, Imperial’s Steel Structures Research Group compelted small-scale destructive material and cross-section testing, computer modeling and large-scale non-destructive real-world testing on the pedestrian bridge.
The research program also included the development of an advanced sensor network that will measure the bridge’s health in real-time, how it changes over its lifespan and how the public interacts with the 3D-printed infrastructure.
According to the scientists, the data from the sensors will be put into a “digital twin” of the bridge—a computerized version that will imitate the physical bridge with growing accuracy in real-time. The performance and behavior of the physical bridge will be tested against the digital twin, which will help answer questions about the long-term behavior of 3D-printed steel, as well as its use in real-world settings and future construction projects.
The bridge's digital twin. Credit: Imperial College London
“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,” explained program lead Mark Girolami of The Alan Turing Institute.
Gardner agrees, emphasizing that the sensors that turn the bridge into a “living laboratory” of sorts are absolutely vital to the future of the bridge and 3D printing on a large scale.
“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,” he said.
The data captured from the bridge will be made available to other researchers worldwide who want to work with the Turing scientists to analyze the results.
Photo: The bridge was installed over the Oudezijds Achterburgwal canal in Amsterdam’s Red Light District on July 15, 2021. Credit: Imperial College London.