Technology benefits bridge

The advanced technology crews are using to replace the Woodrow Wilson Bridge is cost-effective and will mean fewer potholes and road construction closures, private builders and federal transportation officials said yesterday.

“The Wilson Bridge project so far has saved us some $20 million in nine months, and we are doing this by using these new innovative methods,” Transportation Secretary Norman Y. Mineta said during a tour of the project. Mr. Mineta witnessed how crews use the new technology to improve construction of the new bridge, which is a key link on the Capital Beltway and Interstate 95.

To replace the 43-year-old bridge, crews are using premolded concrete slabs that snap together like puzzle pieces, support structures made of polymer composites, computer-controlled centrifugal pavers, quick-drying concrete and “self-consolidating” concrete that pours like water.

Construction officials said the new equipment saves time and money.

“This is about putting the driver first,” said Byron N. Lord, program coordinator for the federal Highways for Life program. “Prefabricated bridge surfaces last longer, take half the time to set up, and are much smoother to drive on.”

Lon Anderson, director of public and government relations for AAA Mid-Atlantic, said the proof remains to be seen.

“If what the manufacturers are saying is true, then premolded parts are absolutely amazing,” Mr. Anderson said. “But give them 15 years of D.C. traffic, snowstorms and salt, and the truth will emerge.”

Premolded concrete is wrapped and bonded by machine, often at East Coast factories, and then shipped to construction sites like the Wilson Bridge.

John S. Dick, structures director for the Chicago-based Precast/Prestressed Concrete Institute, said the technology now accounts for 60 percent of all bridgework in the United States.

“The benefits are obvious,” Mr. Dick said. “You can do the work at night, without interrupting traffic flow during the day.”

H. John Marcelle, vice president of the New York-based Fort Miller Company, said precast bridges can cut a 100-day job by half and will last 50 to 75 years before needing repairs. Mr. Marcelle said over the last 15 years his company has laid more than 2 million square feet of prefabricated bridgework, including the Tappan Zee Bridge over the Hudson River near White Plains, N.Y.

James Ruddell, construction manager of the Wilson Bridge project, said his crews recently designed a new hydraulic hammer to drive the underwater pylons for the bridge into the ground in one quick operation.

“We did it at night,” he said. “There was no disruption of traffic flow.”

Federal officials said the quick-drying concrete cuts down on road closures by enabling construction crews to work faster. Before yesterday’s demonstration, the concrete dried in less than four hours, compared to the three or four days it takes for conventional cement.

Designers said prefabricated decking made of polymer composites is lighter and more effective at strengthening bridges against earthquakes and structural decay than steel and concrete.

Mr. Mineta also said the prefabricated parts that crews are using to rebuild the bridge are a low environmental risk because they were built away from the Potomac River. “This is only the beginning,” Mr. Mineta said regarding the use of new roadway technologies.

Mr. Lord, whose program is funded by the federal Transportation Department, agreed. “We have plenty of funding for construction,” he said. “Right now we need to get the word out about these technologies. When people see them, the quality of the results speak for themselves.”

The bridge construction began in summer 2001. The existing bridge drawspan links Alexandria with Oxon Hill, along I-95. A pair of higher drawbridges will be built, but that also means replacing four interchanges.

The first new bridge is scheduled for completion in 2006. That will be followed by demolition of the existing bridge and completion of the second span in 2008.

The entire 7.5-mile, $2.43 billion project will be completed in 2011, according to John Undeland, a spokesman for the Woodrow Wilson Bridge Project.