Well before embedded instrumentation delivered data from a February 2009 lateral load test of a bent and pier of the I-10 Twin Span Bridge in New Orleans—and long before the sensors begin a life of service as long-term structural-health monitoring aids this October—devices cast into the bridge's structure were presenting a wealth of data to the industry.
“The instruments that are in the pile foundations had to be placed in the rebar cages for the piles in the casting yard,” says W. Allen Marr, president and CEO of Geocomp Corp., Acton, Mass. The concrete was poured around corrosion monitors, other sensors and polyvinyl-chloride conduits, which provide channels for adding any new instrumentation and cabling.