Vertical excitation of stochastic soil-structure interaction systems

This paper considers two stochastic models for a soil-structure interaction problem with vertical propagation of P waves during strong earthquake moti on. These models include the horizontal and vertical spatial variability of stiffness of the soil medium. The first model involves a two-dimensional s tochastic Winkler foundation, which takes into account the horizontal varia bility of the soil. This model elucidates some experimental results obtaine d on a nuclear power station physical model built in Hualien (Taiwan). The second model is developed as a continuum system of random columns involving , this time, horizontal and vertical random characteristics of the soil med ium. For both models a statistical analysis was performed with respect to d etermining probabilistic properties resonance frequencies and amplitudes df the corresponding transfer functions. The theoretical development and nume rical results demonstrate the importance of considering soil variability fo r geotechnical design applications.