Integrated analysis of LNG tank superstructure and foundation under lateral loading

Abstract

Liquefied natural gas (LNG) storage tanks are often supported by very large pile groups (≥100 piles), which can experience substantial lateral loads such as hurricanes, earthquakes, and floods. However, the existing design standards are premised on the experimental results of the small pile groups (<25 piles). Furthermore, the current design practice considers the superstructure and foundation independently, which apparently do not reflect the soil-pile-superstructure interaction. This study aims to observe how the presence of the LNG tank superstructure influences the foundational response of a 1600-pile group and assess whether the current design approach used in practice is suitable. Three-dimensional finite element models were employed to compare traditional, de-coupled foundation models to the integrated tank-foundation models under Category 3 hurricane wind loads. Effects of LNG weight and foundation stiffness were investigated for the comparison. The results found that large pile groups had greater influence depths of lateral responses than small pile groups. The foundation response in the integrated model varied significantly from the foundation-only models. The amount of LNG in the tank, soil condition, and pile spacing also affected the lateral pile responses, particularly the leading and trailing piles.