Get smart

New technology bringing new standards to measuring bridge conditions

By Tom Kuennen, Contributing Editor

“Smart” bridges are on the way for road agencies burdened with the responsibility of monitoring bridge conditions.

Not-so-old technologies like ground penetrating radar (GPR), acoustic emissions testing and lasers for bridge condition testing are being augmented with advanced mobile radar and laser technologies and today’s nanotechnology, which puts the science of bridge condition monitoring into a whole new era with products such as bridge coatings which can sense trouble within.

In the meantime, reliable, low-cost cellular phone service has lowered the barrier to remote reporting of bridge conditions, as battery-powered systems can “call in” condition reports to an agency computer and database or alert an agency if conditions change abruptly.

Today’s benefits can include better information about bridge conditions, a better database for National Bridge Inventory (NBI) reporting, and, long term, fewer demands on personnel for inspection. But field implementation depends on the ability to make high technology marketable in the field, and on the ability of cash-strapped agencies to pay for it.

Rewards, Barriers to Implementation

Nanotechnology is the latest permutation of bridge condition monitoring, but it caps a decade-and-a-half of activity in high-tech bridge condition monitoring.

“Advanced bridge condition monitoring techniques can provide quantitative condition measurements, as opposed to the subjective assessments that a visual inspector provides,” said Dr. Steven B. Chase, research professor of civil engineering, University of Virginia-Charlotteville Center for Transportation Studies, where he works following a 30-year career with the Federal Highway Administration.

“Many of the new methods can provide indications of conditions that exist prior to a visual indication,” Chase said. “And many of the technologies can measure things that simply aren’t visual.”

Current federal regulations require that a state conduct a bridge inspection every two years. With a total of about 583,000 bridges in the national inventory, in order to inspect nearly 300,000 bridges nationally with the amount of manpower that’s available, efficient and rapid assessments and inspections are required. Today’s new technologies can provide that.

But there are built-in barriers to implementation. Past data, and systems put in place to record the results of those inspections, have been predicated on use of visual inspection, not high-tech. “It will be a long time before these new technologies supplant or add a great deal of opportunity for an agency to save money,” Chase told Better Roads. “The case will have to be made that technology can provide better inspections, with a higher probability of finding a defect that could be significant.”

And staff will have to be trained, he said. “The use of all this technology does require a higher level of capability, training and experience that the typical bridge inspectors do not have,” Chase said. “We’re trying to change that by making the technology easier to use, and produce results that are easier to interpret. We want to change bridge management and inspection practices to integrate the kind of quantitative information this technology can provide, in a way that produces better decision-making. But we have been involved in this a long time, and it will evolve over time. I don’t expect any easy breakthroughs.”

Nonetheless, Chase and his fellow researchers have been fighting to bring the technology to the field. “We are working to bring this technology to bear, to make it easier to apply and to improve the quality of information that’s available to the bridge owners from inspections,” Chase said.