EVALUATION OF SOIL-STRUCTURE INTERACTION ON THE SEISMIC RESPONSE OF LIQUID STORAGE TANKS UNDER NEAR-FIELD GROUND MOTIONS

摘要: Soil-structure interaction (SSI) could affect the seismic response of structures. Since liquid storage tanks are vital structures and must continue their operations under severe earthquakes, their seismic behavior should be studied. Accordingly, the seismic response of liquid storage tanks founded on half space soil is scrutinized under different ground motions. To better comparison, the three considered ground motions are classified based on their pulse like characteristics. To model the liquid storage tanks, the simplified mass-spring model proposed by Malhotra is used and the liquid is modeled as two lumped masses known as sloshing and impulsive, and the interaction of fluid and structure is considered using two coupled springs and dashpots. The SSI effect, also, is considered using a coupled spring and dashpot. Besides, four types of soils are used to consider wide variety of soil properties. To this end, after deriving the equations of motion, the MATLAB programming is employed to obtain the time history responses. Results show that although the SSI effect leads to decrease the impulsive displacement, overturning moment and normalized base shear, the sloshing displacement is not affected by such effects due to its long period.