Futuristic bridge spans Stony Run Bridge: In a day, a rotting wooden span in Cecil County is replaced with one of glass fibers and resin that its makers say will be maintenance-free for 75 years.

December 04, 1997|By Dail Willis | Dail Willis,SUN STAFF

RISING SUN -- They made a little bridge -- and a little history -- up here in Cecil County this week.

In a dawn-to-dark workday Tuesday, about a dozen men tore out the rotting beams and worn span of an old wooden bridge over Stony Run that was 20 feet long and two lanes wide. They replaced it with a futuristic "ready to wear" span made of composite material -- a blend of glass fibers and resin that the makers say will need no maintenance for 75 years.

"This little bridge is truly a milestone for the whole industry," said Scott Hemphill of Hardcore DuPont Composites, the company that designed, constructed and installed the 20-foot long, two-lane bridge on Washington Schoolhouse Road.

The installation is remarkable for two reasons, say engineers and county officials: It's the first full-fledged commercial use of composite material, instead of wood, concrete and steel, for a bridge. And the transition from wooden bridge to composite replacement took 15 hours -- a fraction of the weeks or months necessary for standard bridge construction and replacement.

Quick to install, long to last -- the implications for bridges of the future are so significant that if the Romans had had such composite materials, we might all be speaking Latin now.

"This is very cutting-edge," said Charles J. Dominick, bridge maintenance coordinator with the Cecil County Department of Public Works, which paid $40,000 for the bridge, about half the cost of a standard bridge.

The material is a composite developed by Hardcore founder George Tunis for catamaran construction.

Foam cells are used to construct the desired object. Then the composite material, in 8-foot-square mats, is placed around the foam, a bag is placed over it and the air is removed -- "kind of like that Seal-A-Meal you see on TV, except big," Hemphill said.

Once the air is removed, a man-made resin is poured into the structure, filling the spaces where the air used to be.

Composite is a strong, durable, lightweight material with an astonishing variety of uses. Fighter planes are encased in a carbon version of it. Coors Brewing Co. uses railroad cars made of it to ship its beer cold -- and the composite holds temperature so well that refrigeration is not necessary, Hemphill said. Composite material made by Hardcore is used to construct helicopter decks on rooftops and cargo containers for ships.

So quickly has the use of composite material spread that there are no federal guidelines for it in the transportation industry, Dominick said. So transportation officials and engineers from all over the country will be watching to see how Cecil County's little bridge holds up.

"They're still collecting information -- the University of Delaware is helping develop these federal guidelines," he said. "This is going to be one of the most inspected bridges in Cecil County, if not the United States, for a while anyway."

Dominick said the old bridge, which handled about 200 vehicles a day, had been found to be deteriorating so rapidly that its replacement was nearly an emergency.

The wooden span was built in the 1950s -- no one is sure exactly when because county records on it only go back to the mid-1980s -- and the county had put severe weight restrictions on it.

But recent inspections showed that the bridge might not be safe all winter, so the county decided to replace it. Then came a call from Hemphill, asking if the county was interested in new bridge technology at a favorable price.

Time would not permit competitive bidding, Dominick said, so he negotiated with Hardcore, reducing the bid of $51,000 to $40,000. The bridge was built in about a week, Hemphill said, and stored at Hardcore's plant in Newcastle, until Tuesday.

Construction crews arrived at the bridge site around 7 a.m., and began removing the old bridge. They dug out the asphalt around the bridge with a backhoe and pickaxes, then cut the span into four pieces. An enormous, elaborate crane backed into position and, piece by piece, the old bridge was piled on a flatbed truck -- a process that took about an hour.

Workers then cleaned the concrete abutments -- the shelflike structures on which the bridge rests -- and the ready-made new bridge arrived on another flatbed.

At noon, the crane lifted the new bridge, which weighs 12,000 pounds, off the truck, swung it over Stony Run and kept it suspended above the abutments while the construction crew, Hemphill and Dominick pulled and pushed it into position.

Fifteen minutes later, the crane operator lowered the gray and black bridge into place with hardly a thump.

The ready-made bridge had seven large holes on each side. Workers drilled through the concrete, dropped bolts into the holes and bolted them down.

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