3D seismic response with soil heterogeneity and wave scattering in OpenSees
This paper discusses the on-going development of a 3D site response analysis framework that considers three important non-1D aspects of seismic site response: soil heterogeneity (spatial variability), bidirectional input ground motion, and multi-directional soil constitutive response. This paper focuses on the development and implementation of spatial variability explicitly modelled through correlated random fields, leading to seismic wave scattering. Importantly, the required site-specific inputs to apply the proposed approach in a practical setting are the same as those associated with conventional 1D site response analysis. This approach requires addressing several numerical and computational hurdles in order to enable 3D FE simulations with spatial variability to be computed and processed in a tractable manner. We present our theoretical and computational developments to date for an initial sensitivity study involving 960 2D model realizations (as a stepping stone to 3D), requiring extensive parallelization and high-performance computing resources. Insights on the scalability and parallelization of large dynamic OpenSEES models from this study are shared.