This paper discusses soil-structure interaction (SSI) analyses for a 10-story office building with three levels of basement (10 meters) located in downtown Oakland, California. The objectives of these analyses were to assess the effects of SSI on the response of the building and to develop ground-level input earthquake motions at the base of the building for use by the project structural engineer. The SSI analyses were conducted using the two-dimensional finite element program FLUSH. The results of these analyses indicate that SSI has a negligible effect on horizontal ground motions at and near the building’s predominant period (T ~ 1.8 seconds). Minor but unfavorable SSI effects were found at higher frequencies. The effects of SSI on the vertical motions in the building were for practical purposes, negligible. Parametric studies indicate that more favorable SSI effects may have been realized if the building was surrounded by softer soils
