Spanning technology: Cadets work to improve structural health of bridges

  • Published
  • By Amber Baillie
  • Academy Spirit staff writer
U.S. AIR FORCE ACADEMY. Colo. --  Senior cadets here are working to significantly extend the lifespan of bridges across the country through their latest research.

Six cadets from the engineering mechanics capstone design course are a part of a year-long project to develop effective ways to control corrosion build-up on concrete and steel bridges at the Academy and throughout the country through the concept of cathodic protection.

"Cadets understand they can't stop corrosion," said Kevin Gibbons, a senior scientist at the Center for Aircraft Structural Life Extension -- or "CAStLE" -- Research Center here and team advisor of the project. "It's a natural phenomenon that will continue to occur. They can however, affect where it occurs and the rate at which it occurs."

CAStLE's mission is to provide world-class laboratory support to engineering curriculum cadets.

This week, cadets completed their Preliminary Design Review, which they presented to the department's faculty and staff, proposing the use of sacrificial anodes to protect metal on big, billion-dollar infrastructure such as bridges.

"The anodes are highly active metals that attract corrosion to them, protecting metal you want protected because the corrosion occurs somewhere else," Gibbons said. "As long as the anode has mass and the ability to corrode itself, then it can protect something else."

Many bridges in the country are being retrofitted with sacrificial anodes but the anodes are embedded -- therefore can't be monitored without tearing the bridge apart, Gibbons said.

"Cadets are attempting to develop ways to monitor the status of the anodes so they can assess how far and aggressive corrosion is occurring in that environment and on those bridges," Gibbons said.

Cadets are also looking into using impressed current, where current from energy harvesters such as a solar panel or wind turbine -- that can be taken to a remote area without access to the power grid, is used to impress electrons onto metal needing to be protected, directing corrosion elsewhere, Gibbons said.

Cadets began working on the project in August and are scheduled to complete it in May when they present their findings to the Office of Corrosion Policy and Oversight in Washington, D.C.

"The Office of the Secretary of Defense is sponsoring the project," Gibson said. "The CPO is really interested in cadet development as well as corrosion so they love it when a cadet project can involve corrosion."

During the project cadets will investigate ways to affect the corrosion problem in a positive way and begin with basic research, Gibbons said.

"They have to explore ways within their means, both technologically and financially in order to affect the system and make a positive impact," he said.

Up to this point, cadets have used design tools for the project and will purchase and build a prototype they can test in the spring.

"If they come up with a technique that allows sacrificial anodes to be monitored and replaced in a timely manner it could be huge," Gibbons said.

Cadet 1st Class Zach Schrock, a member of the team, said his favorite aspect of the project is the complexity of the problem.

"There are many different factors that can have an effect on corrosion and to try and find an innovative and effective way to accomplish this has truly been rewarding," he said. "We are putting a tremendous amount of effort into finding ways to inhibit corrosion in bridges."

It's a real-world project, Gibbons said.

"It's not a contrived, made-up assignment," he said. "We all know corrosion is a huge issue on aircraft and on bridges in our country. Billions are spent, and bridges collapse. If we can do anything to contribute in that area, it motivates cadets to see they have that possibility."

For more information, visit www.usafa.af.mil.