Old tires find new role in protecting airport
John Wayne Airport might use 30,000 old tires to protect baggage-screening room during an adjacent demolition.
By JEFF OVERLEY
The Orange County Register
By the middle of summer, John Wayne Airport will embark on the most visible phase yet of a half-billion-dollar expansion project, and that's where the rubber meets the road – or, more accurately, the roof.
In order to protect a baggage-screening room during demolition of a parking garage, officials might cover the room, which is inside the garage, with 30,000 old tires, which will hopefully cushion the blow of falling chunks of concrete.
"We think it looks really promising," airport spokeswoman Jenny Wedge said of the concept.
UC Irvine engineers, who researched the idea by dropping two-ton payloads onto stacks of tires, concur, reporting that a concrete slab designed to mimic the baggage-screening room's roof was unharmed.
"The results were very good – no cracks, no nothing," said Ayman Mosallam, director of the Structural Engineering Testing Hall at UCI.
The protective potential of tires is no new discovery – boat slips and supermarket loading docks often use them as makeshift bumpers – but rarely are discarded Goodyears and Firestones used on such a grand scale.
Last year, during demolition of a parking structure in Connecticut, officials used tires to shield a street from falling debris, but the tires were just one element of a protection system that included soil, chain-link fences and heavy-duty fabric.
Elsewhere, metal alloys have been used as long-term buffers to protect the undersides of bridges from tractor-trailers. But John Wayne Airport only needs a short-term, low-cost fix – and few things come cheaper than used tires.
"That is the power of engineering – you don't have to do very-fancy things to solve a problem," Mosallam said.
To gauge the tires' effectiveness, UCI researchers first dropped a 4,000-pound cylinder onto an unprotected slab. Predictably, the cylinder busted right through the nearly 6-inch-thick concrete block.
When the experiment was repeated with the tires in place, the slab suffered nary a scratch. "I was skeptical, but ... you have to believe it when you see it," Mosallam said.
Tires can only do so much, though. Given the baggage-screening room's vulnerability, a pell-mell demolition of the parking structure would render even a landfill's worth of tires worthless.
As a result, crews will slowly "deconstruct" the parking garage piece by piece, using precision equipment to do in 10 months what a wrecking ball could probably achieve in a matter of a few weeks or months.
To ensure the safety of staffers in the baggage room, which was added after 9/11 and screens about 7,000 pieces of luggage daily, demolition will only occur at night.
The project is part of an ambitious expansion that, by early 2011, hopes to add an extra terminal wing in place of the demolished parking garage and a much-larger parking garage at the end of the new terminal.
It's possible that tires won't be used, but contractors who submit bids next month must submit some sort of plan for protecting the 150-foot-by-150-foot baggage room.
Wedge, the airport spokeswoman, could only laugh when thinking of the possibilities. Maybe, she joked, thousands of balloons or a pit of plastic balls like those at Chuck E. Cheese could also do the trick.
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