LIFTING TANKS · Seismic Analysis of Liquid-Storage Tanks with a Focus on Tank-Base Uplift

Liquid-storage tanks are crucial parts of industrial facilities and public water supply systems. Earthquake damage to tanks in earthquake prone regions can result in severe social, economic, and environmental problems since they are used to store crucial liquids such as water for drinking and fire fighting, petroleum products, and fertilizers. In addition, failure of such tanks leads to devastating effects including destroyed fishing industry, damage to environment, poisoning of water supplies, and health problems, which affect European excellence in protecting environment and public health-safety. However, the seismic response of liquid-storage tanks is highly nonlinear and much more complex than implied in current design standards including European.Tank-base uplift seismic provisions have very little technical verification, become less accurate as the displacement increases, and generally not included in the codes. The literature on seismic performance of tanks indicates that there is an urgent need to evaluate applicability of current seismic provisions and to develop tools for calculating tank-base uplift and its effects on seismic performance of tanks. This is the main objective of the proposed research. Detailed 3D tank finite element (FE) models considering liquid-structure interaction will be developed and verified. The FE models will be used to investigate seismic performance of various liquid-storage tanks using a large number of earthquake records using time-history analysis. A parametric study including effects of earthquake characteristics, tank geometry and liquid content level, and tank site soil properties will be performed. The results will be used to distinguish effects of individual parameters, evaluate adequacy of spring-mass mechanical models and seismic design provisions of tanks from various international codes, and develop simple models for predicting tank-base uplift and its effects on seismic performance of liquid-storage tanks.