Earthquake Response Analysis Of LNG Storage Tank With Seismic Isolation

Natural gas is a kind of clear energy, and the liquefied natural gas (LNG) possesss the advantage of easy shipment and storage, and safety for use, therefore it gains popular in China. The LNG storage tank has been extensively studied and has many applications, but its safety under earthquake ground motion is always a major concern. This paper studied the earthquake reponses of LNG storage tank considering its self weight, sloshing and earthquake motions. The lead rubber bearing system is applied to reduce the earthquake response of LNG storage tank, and the effectiveness of the system is investigated. The contents of the dissertation are as follows.Firstly, using ABAQUS software, a three-dimensional finite element model of LNG tank is established. A seismic isolation system is designed by adopting the lead rubber bearing system, and a corresponding finite element model of LNG tank with seismic isolation is set up. Dynamic characteristics of isolated LNG tank and non-isolated LNG tank are analyzed. The analysis shows that the deformation concentrates in the support leg of the tank for both empty and full loaded cases. For the isolated tank, the major deformation is in the isolator, and structure becomes more flexible.Secondly, the effectiveness of seismic isolation system is investigated for different liquid height in the LNG tank under different seismic grounf motions from two directions and with different seismic intensity. The results show that the effectiveness of isolator is better for empty tank than full filled tank. The results show that with the increase of earthquake intensity, horizontal seismic isolation effect will increase but will be gently.The results obtained in this research provide the basis for design of seismic isolated LNG storage tanks.