Location
San Diego, California
Presentation Date
28 May 2010, 2:00 pm - 3:30 pm
Abstract
The San Diego County Water Authority (Water Authority) is undertaking a raise of the existing San Vicente Dam to provide both emergency and carryover storage to increase local reservoir supplies in San Diego County, California, USA. The emergency storage is required in case of a disruption to the imported water transmission system from floods or earthquakes and the carry-over storage would be utilized to store water during “wet” seasons to carry-over to seasons of drought. The existing San Vicente Dam is a 220 foot (67 m) high concrete gravity dam completed in 1943 with 90,063 acre-feet of storage. The raised San Vicente Dam will be about 337 feet (102.3 m) high, creating an approximately 247,000 acre-foot reservoir. The dam raise will be constructed using the roller compacted concrete (RCC) method. This paper presents details of the seismic hazard evaluation that formed the basis for development of strong ground motions that were considered in final design of the dam raise. The dam is under the jurisdiction of the California Department of Water Resources, Division of Safety of Dams (DSOD) which requires the use of deterministic ground motions for design. However, the earthquake ground motions at the site are largely controlled by background (or random) earthquakes, which cannot be adequately addressed using deterministic methods alone. This prompted the development of supplemental seismic design ground motions based on a probabilistic seismic hazard analysis (PSHA). The PSHA was performed incorporating the latest information on seismic sources and recently developed Next Generation of Attenuation (NGA) relationships. Based on the results of the PSHA, ground motion parameters (response spectra and time histories) were developed for final design of the dam raise. Comparisons of the deterministic and probabilistic ground motions are provided. Application of the NGA relationships resulted in lower estimates of peak ground accelerations than what were obtained based on the previous attenuation relationships due to the use of the site-specific shear wave velocities of the foundation materials.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
5th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Publisher
Missouri University of Science and Technology
Document Version
Final Version
Rights
© 2010 Missouri University of Science and Technology, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Handfelt, Leo D.; Wong, Ivan; Thomas, Patricia; Dawson, Timothy; Zhou, Jim; and Kavanagh, Nicola, "Seismic Hazard Evaluation for Design of San Vicente Dam Raise" (2010). International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. 4.
https://scholarsmine.mst.edu/icrageesd/05icrageesd/session07c/4
Included in
Seismic Hazard Evaluation for Design of San Vicente Dam Raise
San Diego, California
The San Diego County Water Authority (Water Authority) is undertaking a raise of the existing San Vicente Dam to provide both emergency and carryover storage to increase local reservoir supplies in San Diego County, California, USA. The emergency storage is required in case of a disruption to the imported water transmission system from floods or earthquakes and the carry-over storage would be utilized to store water during “wet” seasons to carry-over to seasons of drought. The existing San Vicente Dam is a 220 foot (67 m) high concrete gravity dam completed in 1943 with 90,063 acre-feet of storage. The raised San Vicente Dam will be about 337 feet (102.3 m) high, creating an approximately 247,000 acre-foot reservoir. The dam raise will be constructed using the roller compacted concrete (RCC) method. This paper presents details of the seismic hazard evaluation that formed the basis for development of strong ground motions that were considered in final design of the dam raise. The dam is under the jurisdiction of the California Department of Water Resources, Division of Safety of Dams (DSOD) which requires the use of deterministic ground motions for design. However, the earthquake ground motions at the site are largely controlled by background (or random) earthquakes, which cannot be adequately addressed using deterministic methods alone. This prompted the development of supplemental seismic design ground motions based on a probabilistic seismic hazard analysis (PSHA). The PSHA was performed incorporating the latest information on seismic sources and recently developed Next Generation of Attenuation (NGA) relationships. Based on the results of the PSHA, ground motion parameters (response spectra and time histories) were developed for final design of the dam raise. Comparisons of the deterministic and probabilistic ground motions are provided. Application of the NGA relationships resulted in lower estimates of peak ground accelerations than what were obtained based on the previous attenuation relationships due to the use of the site-specific shear wave velocities of the foundation materials.
