Now part of the Capitol Beltway (I-495), the Woodrow Wilson Memorial Bridge was originally built in the 1960s. Designed to carry only a third of its present day volume, the bridge is the only Potomac River crossing in the southern half of the Washington metropolitan area and a significant traffic bottleneck.
Two new, parallel 6075-foot bridges are being constructed to increase capacity and alleviate congestion. The first, being constructed alongside the existing Woodrow Wilson Bridge, is about one fifth complete. Once the first is open to traffic, the old bridge will be demolished and a new one built in its place. Ultimately the two bridges will provide 12 lanes, matching the existing beltway.
Like the original bridge, the new spans include bascule-style moveable spans to accommodate tall ships. However, because the new structures are 20 feet higher than the original, the number of times the bridge will open is expected to drop 77%, from about 250 per year to just 65, further minimizing traffic delays. The new eight-leaf bascule span has the largest moveable mass of any U.S. bridge.
The $650 million bridge replacement is part of a larger $2.5 billion, 7.5-mile project all falling under the direction of Potomac Crossing Consultants, a joint venture of three engineering firms: Parsons Brinkerhoff, URS, and Rummel, Klepper and Kahl LLP.
Parsons Transportation Group, Baltimore, won the bridge contract through an international design competition. The firm's innovative design provides for a structure that features a traditional arched look, similar to the existing bridge, but uses V-shaped piers to minimize horizontal thrust forces at the foundations. The structurally independent V-piers consist of precast segmental sections that are post-tensioned. They extend about 60 feet down through the river's soft mud bottom to more supportive soils below.
The bridge was originally put out for bid in December 2000, on the heels of the 9/11 terrorist attacks. Only one bid was received, and it was substantially more than expected. After the owner rejected that bid, the project was repackaged into three smaller contracts: approach spans in Maryland and Virginia and the bridge over the Potomac. The resulting total bid price for the reworked package was lower than the original estimate.
Parsons' combination of structural steel and segmental concrete construction on this bridge is meeting complex aesthetic, technical, economic, and environmental objectives. The first bridge should open to traffic in the summer of 2006, while the second is scheduled for completion late in 2008.