A multi-directional numerical approach for the seismic ground response and dynamic soil-structure interaction analyses

This paper describes a numerical approach for the analysis of the seismic ground response and the dynamic soil-structure interaction accounting for the three components of an earthquake motion. The investigation was performed with reference to the case-history of Lotung (Taiwan), where the seismic response of a nuclear power plant model as well as that of its foundation soil were measured during several earthquakes occurred at the site. The numerical analyses were carried out with the finite element code Plaxis, adopting for the soil the constitutive model Hardening Soil model with small strain stiffness. First, the model was validated with respect to the propagation of the vertical component of seismic motion, mainly associated to compressional seismic waves. Then fully 3D dynamic analyses were implemented for the simulation of the strong motion event named LSST7. The good match between numerical predictions and monitoring data proved the effectiveness of the proposed approach.