Bridges

After the 1989 Loma Prieta Earthquake, then California Governor George Deukmejian appointed a Board of Inquiry to investigate the earthquake damage and not only to know what happened, but how to prevent similar damage in the future. From this inquiry, ”three challenges were raised:

  1. Ensure that earthquake risks posed by new construction are acceptable;
  2. Identify and correct unacceptable seismic safety concerns in existing structures, and;
  3. Develop and implement actions that foster the rapid, effective, and economic response to and recovery from damaging earthquakes.“*

Following this inquiry the Governor issued an unprecedented executive order that mandated all state owned bridges, viaducts and raised roadways were to be inspected and seismically retrofitted as required. During this period from 1990 through 2000 ANATECH, a Structural Integrity Associates company was heavily involved providing detailed structural analysis of global bridge models, local components, seismic isolation devices and foundation capacity.

Working with the California Department of Transportation (Caltrans) and several University of California engineering schools, developed new performance-based methodologies to evaluate seismic vulnerabilities and retrofit strategies for key lifeline structures. This approach was based on accurate predictions of the actual behavior of concrete and steel structures subjected to ground motions beyond their design basis.

Nonlinear analysis, using our proven ANACAP-U concrete and steel-analysis-software system, was found effective and accurate in predicting the behavior of many complex cyclic tests performed at structural engineering laboratories at the University of California in San Diego, Berkeley and the University of Nevada at Reno. Such valuable collaboration furthered our ability to accurately predict, for the first time, the response, ductility capacity, and cyclic degradation of concrete and steel structures at loads well past design scenarios. Using these methodologies, we provide unparalleled, analytic support for the retrofit and replacement design efforts on many of California's largest signature bridges, including the Golden Gate, East and West spans of the San Francisco/Oakland Bay Bridge, Richmond-San Rafael, San Mateo, Benicia Martinez, Vincent Thomas and Coronado Bridges. More recently we have used these methodologies in seismic vulnerability studies of the Brooklyn and Queensboro bridges for the New York Department of Transportation (NYDOT.)

Our company applies current research and knowledge learned from recent events such as the Tohoku Earthquake and Tsunami and the 2011 Virginia Earthquake to continually evolve our analytic software and to provide cutting-edge, structural-engineering support services.

*Competing Against Time: Report of the Governor's Board of Inquiry on the 1989 Loma Prieta Earthquake, G.W. Housner, HM.EERI, C.C. Thiel Jr. M.EERI

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