ABSTRACT
This paper discusses the results of three centrifuge experiments on 3-story inelastic structures founded on layered liquefiable soil deposits with and without a thin silt cap. For two of the model structures on different soils, liquefaction was mitigated with prefabricated vertical drains (PVDs) around their perimeter. Test results indicate that use of PVDs reduced the duration of large excess pore pressures in the soil, notably reducing settlement on the soil profile without a silt cap, but the PVDs amplified the seismic demand on the foundation and superstructure. In the case with the silt cap, void redistribution and strain localization limited the seismic demand on the foundation, but amplified transient foundation rotations and lateral deformations in the superstructure with or without PVDs. The presence of thin silt cap impeded drainage out of the lower sand layers and made it difficult for the PVDs to prevent shear localization below the sand-silt interface.
