New Design Method to Evaluate the Seismic Stress of Single Deck Floating Roof for Storage Tanks

Liquid sloshing causes severe damage to the floating roofs of storage tanks. Liquid–roof interaction imposes a complicated distribution of out-of-plane deformation in a single deck floating roof (SDFR), which is the primary source of high seismic stress. This paper proposes a new seismic design procedure for evaluating the seismic stress of an SDFR. This method revises the relationship between vertical deformation of the deck plate and the radial shrinkage of the pontoon, and estimates the nonlinear behavior of the free surface. Moreover, the attenuation of the sloshing wave height attributable to the presence of an SDFR is analytically evaluated. A design flowchart according to the new method is suggested. This method emphasizes the nonlinear effects of large amplitude wave for smaller capacity tanks, and the seismic stress caused by the second sloshing mode for broad tanks.