The seismically vulnerable East Span of the San Francisco-Oakland Bay Bridge will be replaced with a dual east bound and west bound 3.6 km long parallel structure. The cost of the replacement bridge is estimated at $1.7 billion and the bridge will be constructed by the year 2005. The Bay Bridge lies between the Hayward and the San Andreas faults which can generate magnitude 7.5 M and 8.1 M earthquakes, respectively. Performance criteria require that the bridge must be operational immediately following a 1500-year return period earthquake from either of these two faults. Four types of structures will make up the bridge crossing: a low rise post-tensioned concrete box girder near the Oakland shores; followed by a 2.4 km long segmental concrete box girder which connects to; a self-anchored suspension signature span; and a post-tensioned concrete box girder that connects to the east portal of the Yerba Buena Island tunnel. This paper focuses on the design parameters and constraints, the design evolution, the bridge type selection process, the selected design's major structural and architectural characteristics, and the structural details.
展开▼
