Linking physics-based regional-scale numerical seismic simulations with local finite-element analysis to evaluate soil-structure interaction of ground motions

Source-to-site simulations form a strong basis for risk-based probabilistic seismic hazard analysis. With an emerging database of synthetic ground motions, there is a growing need to assess the feasibility of the application of these motions for structural analysis. This article evaluates the robustness of a numerical framework to link high-fidelity geophysics models with local finite element (FE) models to perform site response analysis (SRA) and soil-structure interaction (SSI) evaluation. The regional-scale simulations are carried out in SW4, a physics-based finite difference scheme for seismic wave propagation, from which synthetic ground motions are extracted to be applied at the base of a local FE model of a nuclear reactor building in Livermore Software Technology Corporation (LSTC) Dynamic Analysis (LS-DYNA), an advanced multiphysics simulation software package. The seismic event chosen for simulation is an aftershock from the 2007 Niigata Chuetsu-Oki earthquake. Ground motions recorded at Kashiwazaki Kariwa Nuclear Power Plant (KKNPP) in Japan are used to validate the numerical simulations conducted with both the finite difference and FE methods. Moreover, an inter-code comparison is made between the free-field motions generated by SW4 and LS-DYNA to assess the consistency between these two simulation codes. The simulations conducted in this study focus on horizontal ground motions resolved up to a maximum of 3 Hz. The conclusions recognize the importance of compatibility of near-surface properties when employing simulated ground motions toward SRA and SSI for a successful linking approach.