SLOPING LEGS KEEP BRIDGE PIERS ABOVE WATER

Designers of the Prince William Parkway were challenged when the time came to design a highway bridge over the Occoquan Reservoir in Manassas, Virginia. The reservoir is a source of drinking water for Fairfax County. The design objective for the bridge, therefore, was to provide a long center span to keep the piers out of the reservoir except during periods of very heavy flooding. The designers accomplished their objective by implementing a sloping steel pier leg configuration that was efficient in clearing the waterway and in limiting the length of the center span. This article presents information on the bridge's design, substructure, and superstructure. Some environmental and construction issues are addressed also.