Response of cylindrical steel tank under stochastically generated non-uniform earthquake excitation

Cylindrical steel tanks are very important structures in industrial facilities since their application is related to storing different types of products. Their safety and reliability have become a crucial issue because any damage may cause significant consequences, including ecological disaster. The most dangerous dynamic load acting on cylindrical steel tanks is related to earthquakes, especially that the seismic excitation may differ from place to place due to spatial seismic effects related to the propagation of seismic wave. Previous studies have confirmed that such non-uniform earthquake excitation may influence the response of large structures significantly. Stochastic methods of analysis have become an advantageous approach to simulate a spatiotemporal variation of ground motion field for the earthquake engineering problems. The aim of the present paper is to show the results of FEM numerical investigation focused on the response of a cylindrical steel tank under stochastically generated non-uniform earthquake excitation. The analysis has been conducted for the tank fully filled with petroleum. A method of conditional stochastic simulation of ground motions, using the spatiotemporal correlation function, has been applied to generate unknown acceleration time histories for different support locations, based on the earthquake record specified for one location. The results of the analysis clearly indicate that the consideration of spatial effects related to seismic wave propagation leads to the considerable changes in the response of cylindrical steel tank under earthquake excitation. It has also been shown that the application of the stochastic simulation with the spatiotemporal correlation function is an effective method which can be successfully used to generate earthquake records in different locations so as to consider the non-uniform ground motion excitation.