Impacts of Pile Foundation Arrangement on Seismic Response of LNG Tanks Considering Soil-Foundation-Structure Interaction

Liquefied natural gas (LNG) is cleaner and cheaper for power generation than traditional energy sources. Many tanks that store LNG are located in coastal areas with less favorable geotechnical conditions and often in seismically active regions. The seismic loads acting on LNG tanks are highly affected by the soil-foundation-structure interaction (SFSI) and evaluating this effect is quite challenging as a result of the nonlinear response of the structure and foundation interacting with the soil. This paper presents the application of a three-dimensional (3D) numerical simulation technique to study the impacts of foundation type on the seismic behavior of a large LNG tank considering the SFSI effects. Fully nonlinear dynamic analysis under the influence of the 1994 Northridge and 1995 Kobe earthquakes are performed using finite-element analysis software ABAQUS version 2018 to assess the LNG tank seismic response under different foundation types, namely, end-bearing pile foundation and pile-raft foundation with two different frictional pile lengths. The results show the importance of the SFSI effect in evaluation of the seismic response of LNG tanks built on pile foundations. Indeed, choice of the deep foundation system and composition of the foundation in terms of raft effects and pile length can significantly change the dynamic response of an LNG tank and thus seismic forces in the foundation and superstructure.