I-205 Columbia River Bridge: Design and Construction

The I-205 Columbia River Bridge is the final link in a forty-mile circumferential highway east of Portland, Oregon and Vancouver, Washington. It is one of the largest single projects using prestressed post-tensioned concrete box girders in the United States today. Concepts for the structure were defined in a type study which compared construction cost, maintenance cost, constructability, and aesthetics of various alternatives. Continuously post-tensioned box girders constructed on falsework and precast segmental box girders (free cantilever erection) are used in the 7,500-ft-long (2286 m) dual structures. Each of the structures is 68 ft (20.7 m) wide. River piers of cofferdam, caisson, segmental precast-concrete shell construction techniques were developed for various applicable locations. Construction, presently underway, is expected to be completed in 1982.