The New SAS Bay Bridge: Seismic Safety and Earthquake Engineering Issues
Dr. Astaneh after briefly summarizing the performance of the 1936 Bay Bridge during the 1989 Loma Prieta earthquake and discussing seismic performance of the 1936 West Suspension Spans, will focus on the 2013 SAS Bay Bridge and share his findings on the causes and consequences of more than 15 design, construction and inspection problems that have resulted in making the seismic resistance of the new SAS Bay Bridge debatable, its duration of construction unacceptably long, and its cost overruns astronomical. He will discuss the reasons why the SAS Bay Bridge ended up being so problematic and the lessons learned from this project, with emphasis on the questionable seismic performance of the main tower and the bridge as a whole with more than 2,200 hydrogen-embrittled anchor rods and bolts used in the most seismically critical connections of the new bridge. The talk will conclude with proposed repair and retrofit plans that if implemented can mitigate the existing seismic hazards posed by the inevitable fracture of the hydrogen-embrittled anchor rods and bolts and the local buckling of the tower shafts, none being an acceptable seismic performance.