ASCE Orange County Geo-Institute Event – Nonlinear 3D Dynamic SSI Analyses of a Caisson Wall

Presentation Abstract Diemer plant, owned and operated by Metropolitan Water District, serves approximately 4 million people in Los Angeles and Orange Counties. The plant is in a seismically active region and approximately 0.5 km from the active Whittier Fault, capable of generating Mw 6.8 earthquake. The plant was constructed in 1963 by cutting off the top of a ridge and placing excavated materials in adjacent ravines without removing colluvium and compacted to produce a level pad. The fill slopes have an inclination of 1.5H:1V, which is steeper than the current 2H:1V. The plant’s 121” diameter filter outlet conduit (FOC) is buried about 7 ft while crossing a 400-foot length of the northeast fill slope (NFS). The NFS is evaluated to be marginally stable under static loading conditions and do not have adequate seismic stability under an MCE event.  Seismic performance of the FOC was evaluated by performing nonlinear dynamic SSI analysis using…