Numerical investigation of the impact of hydrodynamic load on light-wood frame residential structures considering fluid-structure interaction

The increase in the frequency of devastating hurricanes has led to heightened interest in evaluating the vulnerability of coastal infrastructure by structural engineers, insurance companies, and government agencies involved in disaster mitigation efforts, such as the Federal Emergency Management Agency (FEMA). Assessing the vulnerability of the coastal building stock is an important step in ensuring structural resilience after major natural hazards, such as hurricanes, floods, and tsunamis. Light wood frame (LWF) structures comprise the bulk of residential building stock and are especially prone to damage. This paper discusses the performance assessment of a full-scale LWF building, representative of structures in coastal communities, under the impact of surge wave bores. The novelty of this work is primarily that it explicitly accounts for the fluid-structure interaction effects due to the impact of surge wave bores on the LWF structure using computational fluid dynamics (CFD). This work further identifies salient damage states and carries out holistic damage characterization for varying intensities of bore depth and velocities. The adopted finite element (FE) modeling strategy is validated via test data from scaled timber-wall components subjected to tsunami bores. The adopted FE modeling strategy employs the Coupled Eulerian-Lagrangian (CEL) technique to simulate fluid-structure interaction effects. The validated FE modeling strategy is subsequently used to generate a detailed FE model of an archetypical single-story LWF structure typical of coastal regions. Analyses are conducted under surge waves, and the obtained impact forces are compared with those calculated from analytical equations available in the literature. It was observed that the analytical equations provide good estimates of the surge wave impact force, while providing a reasonable upper bound for the steady-state hydrodynamic drag forces. Finally, a parametric study is conducted to assess the behavior of building components under the combined effect of water depth and velocity. The performance of the buildings is quantified in terms of the damage experienced by individual timber walls. It was observed that the 95th percentile water depth and velocity resulted in damage of 87% (damage state 4) and 38% (damage state 2) to the front and side walls of the structure, respectively.