نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
Background: Aboveground cylindrical steel storage tanks are widely used for storing water, petroleum products, and other essential liquids, making them key components of industrial infrastructure. Because these structures are highly susceptible to seismic loading, their damage or failure during earthquakes can result in significant economic and environmental consequences. Therefore, understanding their dynamic behavior is crucial for ensuring their safe and reliable performance. In this context, the present study examines the effects of different soil conditions on the vibration characteristics, natural frequencies, and effective modal mass participation of fluid-filled steel storage tanks.
Methods: In this study, the results of free-vibration analysis of anchored steel cylindrical tanks are investigated using the finite element method while accounting for fluid–structure–soil interaction. The full-scale steel tanks were designed according to the seismic design provisions of the API 650 standard. The steel tank diameter is 30 meters, and the height-to-diameter ratios (H/D) for the broad and slender tanks are 0.4 and 0.8, respectively. In the finite element models, three soil mediums with appropriate dimensions, representing hard, medium, and soft soil layers, were considered.
Results: The natural frequencies, mode shapes, modal mass participation factors, and hydrodynamic pressure distributions of the impulsive mode were calculated using the free-vibration response of tanks with and without soil–structure interaction.
Conclusion: The results indicate that considering soil–structure interaction has a greater influence on the free-vibration response of slender tanks compared to broad tanks. When soil–structure interaction is included, the modal mass participation factor of the slender tank with a flexible foundation decreases by 33% compared to the fixed-base support condition. Softening of the soil beneath the tank leads to a significant reduction in the hydrodynamic pressure acting on the shell of the slender tank in comparison with the broad tank. In the slender tank, soil softening causes a notable change in the hydrodynamic pressure distribution. Accounting for soil–structure interaction in broad tanks reduces the amplitude of the modal shape function in the mid-height region of the tank shell, whereas its effect on the slender tank is negligible.
کلیدواژهها English
