An Open and Shut Case
Sunday, November 9, 2008
While Woodrow Wilson Bridge commuters will have to wait until the end of the year for express lanes to open, the new bridge has brought a dramatic yet overlooked improvement to those who use the bridge frequently.
Designers expected that the drawbridge portion of the span would be opened less frequently. But new data show just how dramatic that reduction has been.
The old bridge opened an average of 260 times a year, meaning the Capital Beltway would come to a complete stop while ships passed through its open gates.
Engineers designed the new bridge 28 feet higher, which they expected would reduce the number of openings to about 60 a year.
But the news has been dramatically better. In the year ending Oct. 31, the drawbridge only had to be opened 15 times, according to bridge officials.
"It's like a Christmas present that was unexpected," said John Townsend, spokesman for AAA Mid-Atlantic, who said bridge openings were a headache for area commuters as well as long-distance travelers on Interstate 95.
A greater improvement will come next month, when an additional two express lanes in each direction will open. The lanes will separate through-traffic and local commuters, and ease congestion on the heavily used Potomac crossing.
· The original six-lane bridge was built in 1961 and was projected to serve 75,000 vehicles a day. By 1996, it was carrying 195,000 vehicles a day.
· Construction of the new 12-lane bridge began in October 2000 with river dredging. In July 2001, the first of 1,039 piles that support the 17 sets of piers was driven. Some go as deep as 210 feet.
· The first of the two spans opened to traffic in 2006. In August, the old bridge was demolished and the rubble is being used to build a reef in the Chesapeake Bay.
· So far, the bridge project has taken 10 million worker hours and 44,000 tons of steel, the equivalent of 19,000 cars. More than 100,000 tons of concrete were used in the bridge superstructure.
· The bridge deck area is 34 acres, the equivalent of five Nimitz-class aircraft carriers.
· Each drawbridge leaf weighs 2,000 tons.