In this study, several parametric studies were executed for finding out the effect of sloshing and structural responses due to earthquake. Using the method developed for analyzing LNG storage tank, seismic analysis was conducted for LNG tank with 150,000m3 storage capacity. The seismic responses such as sloshing height and overturning moment were analyzed for different base conditions of fixed base and isolated base. Also the results for different liquid height in the tank were calculated and compared.
As the consumption of LNG is increasing, the need for the storage tank is also keep growing. Thus, more LNG storage tanks are required to meet the growing consumption of LNG. However, the design, construction and analysis of LNG storage facility need highly advanced technology compared to the general structures due to the fluid-structure interaction and the low temperature of LNG. Among them, one of the most important elements to be considered in the design of LNG storage tank is earthquake since LNG storage tanks are susceptible to damage when subjected to seismic excitations. When earthquake occurs, LNG storage tank receives a big impact pressure at the wall and bottom plate by dynamic conduct of the interior fluid. The overturning moment caused by hydrodynamic pressure tends to lift the tank off its foundation and develops highly-concentrated compressive stresses which may cause buckling of the shell. Also, in case of using base isolation under the tank bottom, sloshing of interior fluid becomes excessive and thereby impact load occurs at the wall and hitch of the roof. Sloshing height is also an important factor in design of LNG storage tank especially in suspended-deck type tank which can be damaged when high sloshing occurs.
