Town Installs World's First 3D-Printed Bridge

Thu December 21, 2017
Emily Buenzle

The world's first 3D-printed bridge was recently installed in the Netherlands. The bridge, which measures 26 ft. by 11 ft., was built by Eindhoven University of Technology, which researches 3D concrete printing methods, The University Network reported.

Crews installed the bridge, which will support hundreds of travelling bicyclists every day, in the town of Gemert as part of the Noord-Om project, an extensive road construction endeavor run by the BAM Infra company. The bridge, which is meant to remain in operation for at least 30 years, was tested in the lab and on-site with a 5-ton weight, much more than it will ever hold in practice, The University Network reported.

According to T.A.M. Salet, concrete structures professor at Eindhoven University of Technology, the school is attempting to refine the 3D printing process so that it is "robust and repeatable," flowing easily from start to finish. Salet said the open-system process allows the robot to read the design drawing, print and make any corrections, The University Network reported.

The Process

After looking at the university's research, industry partners thought of the concept of 3D-printing a bridge earlier this year, prompting the university to create a process to add reinforcement cables while simultaneously laying a piece of concrete. The cables serve the same purpose as reinforcement mesh would in a more conventional application, The University Network reported. After researchers perfected the process, Salet said the printing only took two weeks to complete.

"We had to deliver in time since it is part of a real project," Salet said. "Luckily and with support of a lot of students and industry we managed. It is for this reason we kept the design simple. Expect more exciting shapes soon."

The Benefits

There's no doubt that 3D printed structures are an amazing engineering feat on their own, but these distinct benefits make the process all the more interesting:

• 3D-printed concrete uses less concrete than more traditional methods. The printer conserves the material by only placing concrete where it needs to go, which, in turn, helps to reduce CO2 emissions.
• A 3D printer can manipulate concrete into any shape needed, making it a much more versatile option than molds.
• The process is faster, since it eliminates the need to build forms, and allows for reinforcement to be added as the concrete is being poured. According to researchers, in the future, this method will be close to three times faster than traditional concrete processes.

What's Next?

So far, Salet said he and his team have printed "a pavilion, some architectural elements like a bench and a wall, [and] a vault by means of shell elements that we assembled afterwards," The University Network reported. The team is also in the process of creating five houses.

"However, the focus was so far on the development of knowledge," said Salet. "An interesting achievement is the option to reinforce the printed concrete immediately during the print process. We used the device to reinforce the bridge in the transverse direction. Longitudinally, it is pre-stressed."