Search for: All records

Design code-based “life-safety” requirements for structural earthquake and tsunami design offer reasonable guidelines to construct buildings that will remain standing during a tsunami or seismic event. Much less consideration has been given to assessing structural resilience during sequential earthquake and tsunami multi-hazard events. Such events present a series of extreme loading scenarios, where damage sustained during the earthquake influences structural performance during the subsequent inundation. Similar difficulties exist with respect to damage sustained during tropical events, as wind and fluid loading may vary with structural response or accumulated damage. To help ensure critical structures meet a “life-safety” level of performance during such multi-hazard events, analysis software capable of simulating simultaneous structural and fluid dynamics must be developed. To address this gap in understanding of non-linear fluid-structure-interaction (FSI), an open-source tool (FOAMySees) was developed for simulation of tsunami and wave impact analysis of post-earthquake non-linear structural response of buildings. The tool is comprised of the Open-source Field Operation And Manipulation software package and OpenSeesPy, a Python 3 interpreter of OpenSees. The programs are coupledviapreCICE, a coupling library for partitioned multi-physics simulation. FOAMySees has been written to work in a Linux OS environment with HPC clusters in mind. The FOAMySees program offers a partitioned conventional-serial-staggered coupling scheme, with optional implicit iteration techniques to ensure a strongly-coupled two-way FSI solution. While FOAMySees was developed specifically for tsunami-resilience analysis, it may be utilized for other FSI applications with ease. With this coupled Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) program, tsunami and earthquake simulations may be run sequentially or simultaneously, allowing for the evaluation of non-linear structural response to multi-hazard excitation.

 

During a tsunami or storm surge event, coastal infrastructure and ports are subject to a series of disparate physical hazards that can cause significant damage and loss of life. Among these, debris impact loading during inundation events is chaotic, complex, and thus far minimally understood, especially when considering the accumulation of individual debris into a large debris field. This work provides the results of a comprehensive experimental study of the impact and subsequent damming of chaotic debris fields, including more than 400 individual trials; this scope of this paper describes the experimental design and initial analysis of wave-driven debris-induced loading for select configurations. These data include both the impact phenomena and subsequent damming by debris accumulation and find strong correlation between increasing debris field density and high impact forces. High frequency impact forces and low frequency damming signals are considered via fast Fourier transform methods. Overall trends in wave-induced debris forcing from large debris fields are presented. 

Solving the shallow water equations efficiently is critical to the study of natural hazards induced by tsunami and storm surge, since it provides more response time in an early warning system and allows more runs to be done for probabilistic assessment where thousands of runs may be required. Using adaptive mesh refinement speeds up the process by greatly reducing computational demands while accelerating the code using the graphics processing unit (GPU) does so through using faster hardware. Combining both, we present an efficient CUDA implementation of GeoClaw, an open source Godunov‐type high‐resolution finite volume numerical scheme on adaptive grids for shallow water system with varying topography. The use of adaptive mesh refinement and spherical coordinates allows modeling transoceanic tsunami simulation. Numerical experiments on the 2011 Japan tsunami and a local tsunami triggered by a hypotheticalMw 7.3 earthquake on the Seattle Fault illustrate the correctness and efficiency of the code, which implements a simplified dimensionally split version of the algorithms. Both numerical simulations are conducted on subregions on a sphere with adaptive grids that adequately resolve the propagating waves. The implementation is shown to be accurate and faster than the original when using Central Processing Units (CPUs) alone. The GPU implementation, when running on a single GPU, is observed to be 3.6 to 6.4 times faster than the original model running in parallel on a 16‐core CPU. Three metrics are proposed to evaluate relative performance of the model, which shows efficient usage of hardware resources.