HR: 0800h
AN: S21A-0233    [Abstracts]
TI: Site Characterization and Seismic Response of Dumbarton Bridge
AU: * Ke, T
EM: t.ke@eathmech.com
AF: Earth Mechanics, Inc., 17660 Newhope St., Suite E, Fountain Valley, CA 92708, United States
AU: Castle, J
EM: j.castle@eathmech.com
AF: Earth Mechanics, Inc., 17660 Newhope St., Suite E, Fountain Valley, CA 92708, United States
AU: Yang, C
EM: c.yang@earthmech.com
AF: Earth Mechanics, Inc., 17660 Newhope St., Suite E, Fountain Valley, CA 92708, United States
AU: Law, H
EM: h.law@earthmech.com
AF: Earth Mechanics, Inc., 17660 Newhope St., Suite E, Fountain Valley, CA 92708, United States
AU: Lam, I
EM: p.lam@earthmech.com
AF: Earth Mechanics, Inc., 17660 Newhope St., Suite E, Fountain Valley, CA 92708, United States
AU: Mohan, S
EM: saba_mohan@dot.ca.gov
AF: California Department of Transportation, 5900 Folsom Blvd, Sacramento, CA 95819, United States
AB: The existing Dumbarton Toll Bridge was built in 1982, connecting the cities of Newark and East Palo Alto, California. The initial vulnerability studies conducted by California Department of Transportation (Caltrans) in 2004 indicated that the performance of the bridge during a maximum credible earthquake was uncertain. With over 18 years of practical experience in geotechnical and earthquake engineering, Earth Mechanics, Inc. (EMI) has been retained by the Bay Area Toll Authority and Caltrans to perform the necessary study for the seismic evaluation of the bridge. An extensive field investigation, consisting of 14 soil borings, six down-hole seismic loggings, seven vane shear tests, 33 cone penetrometer tests and an offshore geophysical survey, was undertaken both on-land and over-water at the site. The investigation resulted in a subsurface profile similar to the one dated 1982 (but with more local zones identified), and provided more reliable data for subsequent engineering analyses. According to probabilistic and deterministic earthquake analyses, a 1,000-year return period spectrum was adopted for the Safety Evaluation Earthquake (SEE), with seven sets of rock motion time histories generated. Site response and kinematic soil-pile interaction analyses were carried out at selected piers to develop the ARS design criteria for the bridge that are site and structure specific, and incorporate state-of-the- art seismic design principles. The axial capacity and lateral push-over behavior of each pier was also examined to ensure its sound performance at SEE levels. The current study provides an illustration of the recent great advances in site investigation and geotechnical analysis.
UR: http://www.earthmech.com
DE: 3238 Prediction (3245, 4263)
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting