(1) The main body of the tank (sidewall and bottom plate) is modeled by shell elements.
(2) The floating roof is modeled with composite shell elements and the rib.
(3) The foundation slab is modeled by shell elements for section force evaluation.
(4) The sand mat and macadam on a foundation slab are modeled by solid elements.
(5) A bunch of few piles are modeled by beam elements.
(6) Ground is modeled by a virtual spring.