Stress Patterns in Single Deck Floating Roofs Subjected to Ground Motion Accelerations

Abstract

This paper investigates the induced stresses in circular single deck roofs floating on seismically excited storage tanks. Equations of motion are derived using variational principle. Response of deck floating roofs is evaluated for two different classes of ground motions; near-source and long-period far-field records. Besides time histories and frequency contents for a specific tank, peak value diagrams of stress for tanks with different radii are illustrated. Results indicate two critical locations in the deck roofs: one near the center of the roof and the other along the deck-pontoon interface. It is shown that near-source ground motions produce larger stresses at the inner critical radius of the deck but far-field ground motions lead to larger stresses in deck-pontoon interface. The results could have practical implications in the design process of floating roofed cylindrical tanks.