Title: Impact of Loma Prieta Earthquakeon Seismic Design of Concrete Bridges—California Perspective

Author(s): J. E. Roberts

Publication: Symposium Paper

Volume: 187

Issue:

Appears on pages(s): 1-16

Keywords: confinement; displacements; ductility; nonlinear analysis; retrofit; seismic design

DOI: 10.14359/5591

Date: 6/1/1999

Abstract:
Almost nine years have passed since the disastrous Loma Prieta earthquake of October 17, 1989 and eight years have passed since the Governor's Board of Inquiry into the cause of highway structure failures during that earthquake issued its final report with the warning title" Competing Against Time". The California Department of Transportation has developed improved Seismic Performance Criteria, Seismic Design Specifications, seismic design procedures, and construction detail based on lessons learned from the 1971 San Fernando earthquake and subsequent seismic events. The success of the Bridge Seismic Design and Retrofit program and the success of future seismic design for California bridges is based, to a large degree, on an unprecedented accelerated and "problem-focused" seismic research program. The Department has spent over $40 million on this research and physical testing of details. This research has provided the bridge design community the assurance that the new specifications and design details perform reliably and meet the performance criteria. Caltrans staff engineers, consulting firms, independent Peer Review Teams, and university researchers have cooperated in this program of Bridge Seismic Design and Retrofit Strengthening to meet the challenge presented in the June, 1990 Board of Inquiry report. The eight year old Seismic Advisory Board has been an invaluable asset in reviewing the performance criteria, design specifications, design procedures, and construction details for both new design and retrofit strengthening of older, non-ductile bridges.