Can 3D Printing Help Repair the Nation's Aging Bridges?

When you're behind the wheel, few sights are as disheartening as a bright orange "road work ahead" sign. No one enjoys sitting in traffic due to construction, yet such disruptions are necessary to repair deteriorating infrastructure for public safety. 

According to the 2025 Report Card for America’s Infrastructure, more than half of all bridges are in poor or fair condition. “If you’ve left your house today, chances are high you’ve gone over or under a fair or poor bridge,” says Simos Gerasimidis, associate professor of civil and environmental engineering. 

For the past decade, Gerasimidis’s research group has collaborated with the Massachusetts Department of Transportation (MassDOT) on research targeting the health of bridges in the Commonwealth, many built after the Second World War and now reaching the end of their natural lifespan. Gerasimidis’s group is using cutting-edge technology and developing innovative solutions to make bridge repairs smarter, more efficient, and ultimately less disruptive to the public. 

Through this collaboration, the MassDOT has provided actual beams from old bridges, which the UMass researchers study in the university’s Robert B. Brack Structural Testing Facility. In a series of experiments, using high-fidelity computational modeling, the researchers developed a new set of guidelines to assess the remaining capacity of corroded beams. These were ultimately incorporated into the state’s Bridge Manual and are now used by engineers working on bridge safety for the state.

The UMass researchers have also utilized cutting-edge 3D Light Detection and Ranging (LiDAR) technology to scan bridge beams to produce detailed maps of corrosion, providing valuable information for bridge maintenance. 

From there, the researchers turned their attention to bridge repairs, exploring additive manufacturing methods—commonly known as 3D printing—which they believe could save time and money, and be less disruptive to passing traffic compared to traditional repair methods. For more than a decade, 3D printing has been used to repair structures such as submarines, airplanes, and ships, but bridges present unique challenges due to their size and because the 3D printer must be brought on site to perform repairs. 

With support from the MassDOT, the Massachusetts Technology Collaborative (MassTech), the U.S. Department of Transportation, and the Federal Highway Administration, UMass researchers partnered with the research group of Professor John Hart at MIT to explore different 3D printing techniques in the lab. They found the “cold spray” technique to be optimal for bridge repairs. 

According to Gerasimidis, this technique involves heating up steel particles in a powder form, thus accelerating their velocity, then spraying the particles onto the bridge surface. The speed involved allows the particles to bond with the bridge surface. The metal powder is sprayed on in layers, building up thickness and repairing corrosion. 

The cold spray technique has several advantages. It is “cold” by metal standards, meaning it does not heat up enough to alter the mechanical properties of the bridge surface. The application machine, while still large, is portable enough to bring to bridges. 

On May 14, 2025, a successful first-of-its-kind, proof-of- concept demonstration of the cold spray technique was used to repair a patch on the red bridge, formerly known as the “Brown Bridge,” first built in 1949, in Great Barrington, Massachusetts. “The repair went very smoothly and was completed in under four hours, much quicker than expected,” Gerasimidis reports. 

“There is still work to be done in terms of research and development, and ultimately this technology will have to undergo a thorough review process for safety before it can be deployed widely,” notes Gerasimidis. However, he adds: “I think this method has a huge potential to change the game in bridge repair. With this technology, we think we can do cheaper, faster repairs than what is done now.”