New York experiments with remote sensing to monitor bridges

NYSERDA (the New York State Energy Research and Development Authority) and the federal government have been testing a remote sensing system on Bridge 1027260. Like Jean Valjean, this bridge has no name. [photopress:kerop.jpg,thumb,alignright] And you can tell that it’s not in New York City, because if it were here, the City Council, whose power is limited to the power to name public objects and thoroughfares – might have already named each lane and approach ramp.

Professor Kerop Janoyan and a team of graduate students from Clarkson University have been monitoring their equipment from a work barge near the bridge. (Since they seem to be working on an exposed, unheated barge, perhaps the bridge and its appurtenances should be named for them

. Popular Logistics will send a correspondent in person to any naming ceremony).

We learned about this from Matthew Wald’s piece in the Times:

The bridge that carries Route 56 over the Raquette River here is so ordinary that it has no name, only a number, 1027260. But for now it is a bridge like no other, studded with instruments like a cardiac patient, giving up secrets that may explain how to keep others from falling.

Bridges are big, dumb pieces of steel and concrete, and mostly out of mind, until one collapses, as the Interstate 35W bridge did in Minneapolis on Aug. 1. Even now, three months later, no one is sure why that happened, but it has focused the attention of engineers on techniques of bridge inspections, and how to diagnose their ills.

At this bridge, a two-lane, 360-foot steel and concrete affair built in the mid-1990s, “we are making the structure smart,” said Ratneshwar Jha, an associate professor of mechanical engineering at nearby Clarkson University.

The Route 56 bridge in far upstate New York has been fitted with 60 wireless sensors that will measure movement, strain and temperature, as a way to judge its structural health.

Engineers have used sensors for years, and lately have tried out wireless sensors, which permit easier readings and, potentially, lower costs. But this $900,000 project, mostly paid for by the New York State Energy Research and Development Authority, is unusual for its scope.

In the meantime, experiments are continuing at the bridge in Colton. On a work barge moored about 100 feet upstream from the bridge, Kerop Janoyan, an associate professor of civil and environmental engineering at Clarkson, watched intensely as a team of three graduate students set up the gauges and transmitters, and collected data on a laptop computer, balanced on an overturned plastic pail. On the screen, the output looked like a voiceprint image. When a car went by, it looked like a louder voice. When a truck passed over, it looked as if the bridge was screaming.

“Bridges are one of the few remaining things that are not monitored electronically,” Mr. Janoyan said. “Everything else has a microchip in it.”

Mr. Janoyan’s chips take readings 128 times a second.

The transmitters were an outgrowth of a military research program trying to monitor movement on battlefields. They cost about $10 each, and the sensors another $10, said Mr. Janoyan, who is hoping to start a business providing electronic monitoring. But it would have to become a regulation before most transportation departments would move to the system, he said.

His team is still testing the transmitters and the receiving antennas. The next step, he said, would be to measure a bridge and then come back a few weeks later and measure it again. If a girder moves differently, or no longer has strain on it, that is a sign of a problem, he said.

Opinion on sensors differs. Some say they can help spot problems before they grow into disasters. “These bridge collapses are sterling reminders we need to embrace technology, which is developing as we speak,” said Paul D. Tonko, president and chief executive of the New York State Energy Research and Development Authority.

At HNTB, an engineering firm based in Kansas City, Mo., that specializes in bridges, Ray McCabe, an engineer, said that applying sensors in the region of a known crack was a good way to see if the flaw was growing.

But Tennessee’s chief bridge engineer, Ed Wasserman, is skeptical. “What works in the laboratory does not necessarily work in the real world bridge environment,” Mr. Wasserman said in an e-mail message.

Engineers have also noted that monitoring systems may not last as long as the bridges themselves, which are designed to work for 75 to 100 years. Ground-penetrating radar can be used on concrete decks, as can infrared thermography, in which engineers look for subtle temperature differences on metal or concrete surfaces that could indicate cracks and voids.

Such high-tech methods are unlikely to become widespread until the safety board issues its report on the cause of the Minneapolis collapse.

For now, said Kelley C. Rehm, head of a committee on bridge engineering at the American Association of State Highway and Transportation Officials, states are better off rechecking their bridges and inspection systems.

“They’re not going to jump onto a bunch of new technology, like putting sensors on bridges, or make any big changes in programs, until they have the report from the safety board,” Ms. Rehm said.

Matthew L. Wald, “Health Care for Bridges: A Search for Diagnostic Tools,”

The New York Times, 1 November 2007.

Professor Janoyan has impressive credentials – and they’re on three several different pages at the Clarkson website. Here are three:

What’s particularly impressive is that Professor Janoyan’s professional interests – in addition to expertise in soil and structural issues – include remote sensing (think specialized network nodes) and sustainable (think green) technologies.