Deck repairs on the Woodrow Wilson Memorial Bridge south of Washington, DC were made during the night, with at least two lanes of traffic kept open at all times. But the most remarkable feature of the repair project was that it was completed more than seven months ahead of schedule at a cost nearly 30 percent below the engineer's estimate. The new deck, composed of precast lightweight concrete panels, cantilevers laterally from the existing steel superstructure, widening the bridge without supplementing the main structural girders.
Typical concrete panels were over 46 feet wide, 10 to 12 feet long and 8 inches thick with a 5-inch haunch at the existing girder. They were post-tensioned transversely at the precasting plant to give bending strength needed because the panels projected beyond the existing superstructure. After placement, the panels were post-tensioned longitudinally to reduce cracking and seal the transverse joints between adjacent panels, thus eliminating water intrusion.
The precast panels were supported by poured-in-place polymer concrete bearing pads on the exterior girder and interior stringers.