Work

Effects of tsunami wave and bathymetric parameters on hydrodynamic forces and structural fragility

Year: 2025

Type: article

Abstract: Tsunamis pose serious risks to coastal regions, often causing severe structural damage and loss of life. Although current design codes prescribe simplified representations of tsunami loads, it remains uncertain whether these assumptions fully reflect the demands imposed by real events. This study examines how tsunami-induced forces and structural vulnerability are influenced by offshore wave characteristics and coastal bathymetry. Tsunami propagation was simulated with a high-resolution numerical model, and inundation depth and flow velocity were extracted at nearshore stations and converted into hydrodynamic forces using ASCE 7–22 provisions. These forces were then applied to nonlinear structural models, and fragility curves were derived under an integrated structural reliability framework. The analysis considers variations in wave period, crest amplitude, trough amplitude, and the number of wave cycles. Bathymetric parameters, including offshore and onshore slope, seafloor friction (represented by the Manning coefficient), and the distance of structures from the shoreline, are also investigated. Results show that increases in Manning coefficient, bathymetric slope, wave period, and shoreline distance are generally associated with reduced structural fragility. For example, increasing the Manning coefficient from 0.025 to 0.04 reduces maximum onshore and offshore tsunami forces by 41 % and 55 %, respectively. Steeper offshore slopes reduce fragility, with serviceability failure probability dropping from 40 % to 3 % as slope decreases from 1/75 to 1/225. Longer wave periods (20–35 min) reduce onshore force by 56 % and serviceability failure probability from 100 % to 0 %. Crest amplitude strongly amplifies vulnerability, with serviceability failures increasing from 0 % at 5.7 m to 70 % at 6.9 m, while trough amplitude has little influence. Additional wave cycles increase cumulative vulnerability, raising serviceability failure probability from 8 % (one wave) to 37 % (three waves). Structures located farther inland consistently experience reduced loading due to energy dissipation during propagation. A comparison with ASCE 7–22 highlights key discrepancies, and new normalized curves are proposed to improve tsunami force estimation. These findings provide a more comprehensive understanding of tsunami effects on structures and support evaluation of the adequacy of code-based assumptions.

Source: Journal of Building Engineering

DOI: 10.1016/j.jobe.2025.115077

Authors: Mostafa Abdelhafeez, Hyoungsu Park, Mohamed Sherif, Amr Ghanem, Do-Soo Moon

Institution: University of Hawaiʻi at Mānoa

Language: English

Topic: Earthquake and Tsunami Effects

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,940

Funders: Hawaii Department of Transportation, National Research Foundation of Korea, Ministry of Science and ICT, South Korea