Concerns on the Seismic and Blast Vulnerabilities of the New East Spans of the Bay Bridge

Abolhassan Astaneh-Asl, Ph.D., P.E., Professor
University of California, Berkeley


On October 17th 1989, a magnitude 7.1 earthquake shook the greater Bay Area, damaged and collapsed a number of buildings, transportation structures and other facilities. One of the major structures damaged, albeit in a minor way, was the eastern part of the San Francisco Oakland Bay Bridge between Yerba Buena Island and the East Bay shore. The main damage was collapse of only two 50-ft long segments of the roadway above a pier which resulted in closure of the bridge until the collapsed area was replaced. The day after the collapse, the speaker, Professor Astaneh, whose area of interest is steel buildings and bridges, started a multi-year investigation of the behavior of this bridge when subjected to earthquakes and blasts. He will share his major findings. The studies indicate that the project may end up being the best example of the worst bridge engineering in history marred with incompetence, flawed design and construction concept and conflicts of interests. A bridge that could be retrofitted safely for less than $300 million and in less than three years will cost more than $6.1 billion and be constructed in 24 years. This is the case with the Self Anchored, Single Tower new East Spans of the Bay Bridge currently under construction. The most striking fact about the new bridge is that from seismic and blast protection point of view it is expected to perform not better than the
the existing east span trusses during a major earthquake or a car bomb attack, both major concerns for such an iconic and important structure with daily traffic of more than 300,000 cars.