New Mexico Tech Researcher Ghosh Develops Bridge-Testing Laser, Nov. 12, 2007

Dr. Ashok Ghosh

by George Zamora

SOCORRO, N.M., Nov. 12, 2007 – A New Mexico Tech researcher has developed a patented laser-based system that can accurately measure extremely small vibrations along structures, which, among other applications, can be used by engineers to better determine the strength and safety of highway bridges.

“By using this new laser-based system for testing bridge superstructures, bridge maintenance engineers will be able perform dynamic tests — tests done while the normal flow of traffic is going over a bridge — at a very fast rate and at a relatively low-cost,” says Ashok K. Ghosh, assistant professor of mechanical engineering at New Mexico Tech and principal inventor of the vibration analysis system.

“By placing small lasers along a structure and aiming the concentrated light at moveable target screens, it is possible to obtain large amounts of data in a short amount of time, which can then be used to quickly determine the dynamic characteristics of a bridge structure along its entire span,” he adds.

Ghosh’s new laser-based system has the potential to detect structural deficiencies in bridges before they result in catastrophic failures, such as occurred in this past summer’s fatal highway bridge collapse in Minnesota.

“Currently, bridge inspections are still being carried out by workers performing only visual inspections as they look for cracks and crevices,” Ghosh says. “By implementing this relatively simple and inexpensive testing method, you can essentially replace all the visual inspections, which is the beginning point of any thorough assessment of bridge structures.”

According to a 2003 study conducted by the American Society of Civil Engineers, more than 160,000 bridges being used throughout the United States were found to be “structurally deficient or functionally obsolete.” This figure represents 27 percent of the nation’s bridges.

Ghosh currently is exploring possible applications of the new laser-based concept with the New Mexico Department of Transportation for conducting vibration analysis of bridges in New Mexico.

The newly patented technology marks Ghosh’s second patent awarded this year.