Building engineers, taking a cue from nature, are beginning to equip the steel and concrete flesh of the constructed world with "nerves" made of glass fibers. These nerves can signal dangerous conditions such as microcracks, excessive strain, or high alkalinity corroding the concrete's reinforcing bars. Engineers can send light through the fibers and watch for changes in color, intensity, and phasing.
Peter Fuhr and Dryver Huston, professors at the University of Vermont, have fitted several structures with optical fibers, including a new science building on their Burlington campus, a hydropower plant on the Winooski River, and resurfaced bridge decks in neighboring areas.
A telemetry system sends structural stress data from the optical fibers in a Middlebury bridge to a computer in the researchers' laboratory. As Fuhr sees it, these kinds of early efforts could lead to "sensitized" cities in which a few people sitting in the cool monitor-glow of an office can track the health of all the major buildings and structures.
Making real this vision of intelligent structures will take some doing, Fuhr cautions. On his wired bridges, he says, "you can tell if trains are on schedule, but most of the stress data is rubbish," meaning they are impossible to interpret just yet. Ironically, the biggest hurdle may come from the construction industry, which Fuhr and others say is loathe to deviate from traditional building codes that do not call for concrete and steel with fiber-optic nerves. For additional information, visit the University of Vermont's Optic Research Lab Web Site: http://issri.emba.uvm.edu/.
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