We have seen in Chapter 3 how wavelet-based formulation is gradually developed for single-degree-of-freedom (SDOF) and two-degree-of-freedom (2-DOF) systems. In case of the 2-DOF system, the equations representing the dynamic motion of the system were uncoupled. So, searching for a solution was not a difficult task. However, in reality most of the systems may not always be representable as a simplified SDOF or 2-DOF system; rather, they would need to be represented with more degrees of freedom. In this chapter, we will take up a unique example of a specific multi-degree-offreedom (MDOF) system and show step-wise how to make valid assumptions to concentrate more on those parameters that would affect the system response to a great extent. The first important consideration would be to include soil interaction in the analysis. In Chapter 3 we have assumed the superstructure to be anchored to rigid foundations, thereby ignoring soilstructure interaction. The other important criterion could be consideration of rocking motion of the structure [29, 30]. During strong ground shakings, it is quite likely that ground-supported structures like liquid storage tanks, buildings, reactors, etc. would be subjected to rocking motions as well. With these considerations, the main objective of this chapter is to define a suitable model with practical assumptions, development of a theoretical formulation based on the wavelet-based technique and providing a closedform analytical solution to the problem. The basic guidelines for such formulation are well proposed in the work by Chatterjee and Basu [31].