A smart bridge for Oklahoma

Friday, November 30th 2001, 12:00 am
By: News On 6

The tricky task of driving on ice and snow. Earlier in the week, motorists were slipping and sliding like they do after every snowfall. And there's no way around it, at least not yet.

News on Six reporter Steve Berg tells us about a new invention that could save money and lives. Bridges are where a lot of accidents happen, because they ice up before the rest of the highway. We might not be able to get smarter drivers, but we could soon have a smart bridge. Jeff Spitler's colleagues joke that it's the bridge to nowhere. But the Oklahoma State engineer says the geothermal smart bridge could actually lead to fewer accidents like this one during Wednesday's icy weather. It melts the ice on the bridge by taking heat from an obvious, plentiful source, our Oklahoma summers. "You know how hot concrete gets in Oklahoma gets in the summer, I don't know if you can really fry an egg on it, but it seems like it. And we actually circulate fluid in these tubes in the bridge deck down into the ground." There the water maintains most of its heat, even months later. "We actually store it from the summer to winter." Then when the road freezes, the warm water, along with an antifreeze mixture, is circulated back through the bridge deck through what they call hydronic tubing, and voila, the ice melts.

In his example, the part of the bridge with snow has no tubing, the melted side does. And it does it all with virtually no man-made energy, but it's still expensive. "I think the biggest hurdle is just keeping the most reasonable, right now, we're just getting ready to build the first full-scale system, and the price is higher than we would like, and I think higher than would be acceptable on a wide scale."

If the geothermal bridge works, it could make these a thing of the past, but it would also get rid of the salt, which is what really does the damage to the bridges. "So instead of lasting 17, 18, 19 years, if it's salted a lot, it might last 50, 60, or maybe even 80 or a hundred years." So while a geothermal smart bridge might cost twice as much, it might last four times longer. But it’s really the lifespan of the motorist they're worried about, more than the lifespan of the bridge. "That's the one thing and the other thing is just that it will be safer." And the benefit of saving lives could be immeasurable.

The State Department of Transportation is getting ready to build the first full-scale smart bridge on I-40 near Weatherford. That happens next spring. Again it costs twice as much, about $140 a square foot, but if it saves lives, they say it's worth it.