Seismic behavior of LNG storage tank considering soil-foundation-structure interaction with different foundation types.

Seismic loads acting on the foundations and the structure have been estimated from the surface free field motion, but those can be changed by the soil-foundation-structure interaction (SFSI) effects. SFSI effect is difficult to evaluate exactly because of the variety of the phenomena depends on such as the soil profiles and the foundation types. In this research, the amount of the dynamic centrifuge tests was performed to observe the seismic behaviors of the liquefied natural gas (LNG) storage tank with different foundation conditions. Test specimens were composed of dry silica soil layer, foundation and LNG storage tank model. Two typical foundation types were used: shallow foundation and pile foundation. In cases of the pile foundation tests the embedment depth of slab was changed. For the input motion, Ofunato and Hachinohe earthquake records with increasing intensity were used to observe the frequency and the intensity effects of the seismic behavior of LNG tank system. From the dynamic centrifuge test results, the accelerations at soil surface, slab and structure were compared.