Seismic Design and Analysis of Concrete Liquid-Containing Tanks

Concrete tanks are used in high seismic regions for water, chemical storage, and treatment. These tanks may be reinforced or prestressed concrete structures with rectangular or round shapes and may locate above or underground. Based on governing codes, such as ACI 350-06, ACI 373, the tanks should have strength, water tight, durability for cracking, and corrosion control. ACI 350.3 also provides equations for seismic forces of rectangular and circular tanks. However, in a design practice, we may still have issues that ACI codes don’t cover, such as tsunami events, and uplifting requirement of underground tanks. The section forces of critical load combinations are difficult to be found unless a 3-D computer model is created. After we have a computer model, we may still doubt what is the impact of soil sub-grade on the base, side soil spring for underground tanks because these data have a very big influence on dynamic properties of tank system, such as the fundamental frequency. We may wander, without these data, if the seismic analysis of tanks per ACI 350.3 is still reliable. Modeling of the complex liquid-structure and soil-structure interaction are required for a reliable design. In this study, the codes and phenomenon of concrete liquid tanks in high seismic regions will be reviewed and summarized, and the seismic analysis based on ACI 350.3 will be illustrated. The finite element methods of pseudo-static seismic analysis and responds analysis following original Houser’s assumption of ACI 350.3 will be presented.