**4. Conclusion**

The functionality of liquid-storage tanks should be ensured during and after natural disasters, e.g., earthquakes, such that under intense ground motions the structural collapse is prevented. Therefore, it is crucial to quantify the safety margin against the structural collapse state for water tanks, which are considered as lifeline structures. Furthermore, the literature shows that the dynamic behavior of these structures is governed by many factors including the tank shape, fluid properties, structural flexibility. Soil characteristics, and the type of supporting structure.

Researchers tend to prefer simple and straightforward modeling techniques for the FE analysis of liquid-tank systems. Different simplified modeling approaches that consider the FSI effects can be used to reduce the complexity and computational cost of liquid-tank systems. The dynamic behavior of liquid-tank systems that is obtained using these modeling techniques can have high accuracy that can match that obtained from continuum liquid-tank systems. A simplified single-mass model could be used if the weight of water equals or exceeds 80% of the overall weight of the liquid-tank system. In the two-mass model representation of liquid-tank system, the hydrodynamic pressure developing within the liquid resulting from the dynamic motion of the liquid tank can be divided into two parts. The liquid mass in the top zone of the tank, called the convective mass, characterizes the motion of the free-liquid-surface. The liquid in the bottom zone of the tank, called the impulsive mass, represents the remaining mass of the fluid and the mass of the structure. A FE model can be represented by a spring-mass model based on Housner's analogy in which the liquid is replaced by two lumped masses: the impulsive and convective masses. The impulsive mass is connected to the tank walls using rigid links and the convective mass is

*A Review on the Dynamic Response of Liquid-Storage Tanks Associated with Fluid-Structure… DOI: http://dx.doi.org/10.5772/intechopen.109197*

connected through elastic springs. This modeling approach is effective in reducing the reduce the computational cost and complexity of liquid-tank systems while resulting in moments and forces that are comparable to that obtained from continuum liquid-medium models subjected to the same ground motion records.