Development of an open-source methodology for simulation of civil engineering structures subject to multi-hazards

Design standards for structural earthquake and tsunami resilience provide guidelines to construct buildings that will remain standing during either a maximum considered tsunami or seismic event. Cascading hazards from earthquakes and tsunamis present a greater challenge to structural designers than individual hazards, as multi-hazard events involve a series of extreme loading stages, where structural damage sustained during one stage might influence performance or resilience during subsequent loading stages. To assist in the investigation of site-specific resilience of structures subject to cascading or multi-hazards through numerical analysis methods, an analysis approach for coupling disparate numerical analysis methods used for earthquake simulation and tsunami inundation simulations was developed and validated against analytical solutions and the results of experiments. This led to the development of a coupling driver, FOAMySees, which facilitates simulation of fluid-structure-interaction (FSI) between standard computational fluid dynamics and finite element analysis models constructed within the OpenFOAM toolbox and OpenSees framework, respectively. The capabilities of OpenFOAM and OpenSees, when combined, allow for the evaluation of nonlinear structural response to multi-hazard excitation. Communication between component analyses is established by the coupling driver through preCICE, a library for multi-physics partitioned coupling. FOAMySees accompanies standard practices for modelling of structures subject to seismic excitation within OpenSees as part of an FSI simulation, which will be useful to analysts aiming to assess the residual capacity or performance of models of structural designs subject to complex three-dimensional loading from tsunami flows following a design-level seismic event. The approach allows for flexible construction of coupled models with validated, open-source, community-maintained software libraries, establishing the capability to conduct analyses that could assist in validating predictive force equations and structural design recommendations for structures subject to various natural hazards.