- The Washington Times - Tuesday, April 30, 2002

LYNCHBURG, Va. (AP) A bridge under construction at the U.S. 29 and U.S. 460 intersection in Lynchburg is being equipped with experimental monitors to provide information on the structural health of the span.
Virginia Technologies Inc. of Charlottesville is donating four computerized micro-instruments to be placed within the structure of the new Pleasant Valley interchange bridge. The devices measure five different conditions in concrete bridge decks and keep tabs on rust on the reinforcement steel, said engineer Robert A. Ross, the company's president.
Most corrosion detection "is low-tech and slow-tech," said Robert G. Kelly, a University of Virginia engineering professor and an authority on corrosion. Mr. Kelly, Mr. Ross and Kurt Hudson, another Virginia Technologies engineer, invented the monitoring system.
The monitoring system is designed to provide key information about the bridge's structural health, which could lead to savings for the state if problems can be discovered and repaired before they become serious.
"Corrosion of the rebar in the reinforced concrete in bridges is a very expensive problem," said Gerardo Clemena, a senior research scientist with the Virginia Transportation Research Council in Charlottesville. "Our intent is to minimize, if not eliminate, that expensive problem."
The National Research Council has estimated the cost of damage to the nation's aging bridges at about $20 billion, increasing by about $500 million per year. Much of the damage is caused by corrosion.
The National Bridge Inventory Study Foundation says needed repairs to the state's nearly 12,000 bridges would cost $2.8 billion.
The Virginia Technologies monitors measure such conditions as moisture, temperature and corrosion-rate indicators. The information can help engineers determine where salt or other agents are eating away at the structure faster than anticipated.
The devices, which weigh less than a pound, will be placed within the Pleasant Valley bridge deck in areas vital to the strength of the span or those prone to corrosion. Concrete will be poured after the devices are in place.
The Virginia Department of Transportation is building the bridge in the relocated U.S. 29 and U.S. 460 intersection, which is part of the $190 million Madison Heights Bypass project.
The devices are linked to a battery-powered data logger next to the bridge. A small solar collector provides electricity to recharge the battery.
A cell-phone modem allows engineers to collect the system's reports remotely. "Kurt never has to leave his desk in Charlottesville," said Mr. Ross, a former University of Virginia research scientist.
The information from the monitors will allow engineers to determine exactly when and where the bridge needs upkeep, and specifically what kind of remediation. This will allow engineers to avoid costly, tedious tests that themselves degrade the bridge.
"It's part of an intelligent maintenance system," Mr. Ross said.

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