Model reduction for structural health monitoring accounting for soil-structure-interaction

This work addresses structural model reduction, a process necessary in structural health monitoring, where large quantities of data are recorded and must be evaluated. Therefore, numerical modelling of a structure is necessary for processing the recorded data and for estimating structural degradation over time. In order to avoid complex structural models and to economize computational resources, reduced order models have to be introduced. The goal is to develop a replacement single-degree-of-freedom oscillator that takes into account soil-structure-interaction effects. The dynamic characteristics of this oscillator are estimated by using the total displacement equality criterion. More specifically, the replacement process exhibits the following characteristics: (i) The complete time history of the “equality parameter” is considered and not just the resonance amplitudes; (ii) the problem is solved in the frequency domain using the complete set of the equations of motion; (iii) the outcome is independent of the excitation motion; (iv) the method can be applied for any mechanical parameter desired; and (v) the foundation impedance matrix is included. Following this development, parametric studies are conducted for assessing the dependency of the dynamic properties of the equivalent oscillator on the soil profile, the inertial characteristics of the foundation and its embedment depth.