Design of the New San Francisco - Oakland Bay Bridge

Abstract

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 $1.5 billion and the bridge will be constructed by the year 2004. 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 distinct structures will make up the bridge crossing: a low rise post-tensioned concrete box girder near the Oakland shore; a 2.4 km long segmental concrete box girder; a self-anchored suspension signature span; and a posttensioned 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. Introduction The San Francisco-Oakland Bay Bridge was constructed in the mid-1930s. At 8 miles long, it was one of the longest high-level bridges in the world at the time. Today, the bridge is a primary route between the San Francisco Peninsula and the East Bay, carrying nearly 280,000 vehicles daily. A variety of bridges span the waterways of the San Francisco Bay. There are suspension bridges such as the Golden Gate Bridge, long skyway bridges such as the San Mateo-Hayward Bridge, and truss bridges such as the Richmond-San Rafael Bridge. Figure 1 is a map of the San Francisco Bay Area showing the location of these bridges. Figure 1 – Geographical Location of Bridge Figure 2 – Damage to Bay Bridge after Loma Prieta Earthquake Pacific Ocean San Francisco Bay Golden Gate Bridge San Francisco/ Oakland Bay Bridge Richmond Bridge Carquinez Bridge Martinez/ Benicia Bridge San Francisco Oakland