The Earthquake Engineering Online Archive

Re-evaluation of the slide in the Lower San Fernando Dam in the earthquake of Feb. 9, 1971

Seed, H. Bolton; Seed, Raymond B.; Harder, Leslie F.; Jong, Hsing-Lian

UCB/EERC-88/04, Earthquake Engineering Research Center, University of California, Berkeley, 1988-04, 124 pages (710.4/S41/1988)

The Lower San Fernando Dam and the field investigations made in 1985 to explore its properties are briefly described. The probable changes in properties of the soils in the embankment since the earthquake occurred in 1971 are analyzed. The standard penetration test data for the sands in the dam in the 1971 and 1985 investigations are reviewed. The results of cyclic load tests performed on the samples obtained in the 1985 investigation are presented and compared with those obtained in 1971 and those expected based on past field performance. The results of steady-state strength tests on samples obtained in the 1985 field exploration program are presented. The properties of the hydraulic fill near the base of the upstream shell, based on the test results and other studies summarized in this report, are presented. The practical significance of the results obtained is discussed. Steady state strengths determined by laboratory testing are compared with those estimated from the known field performance of the upstream shell in this dam and other dams where liquefaction-type failures have occurred. The applicability of analytical methods for evaluating the seismic stability of the Lower San Fernando Dam is reviewed in general. Overall conclusions are given.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-88-04.pdf (8 MB)