Impacts of soil-structure interaction on the structural control of nonlinear systems using adaptive control approach

Though there is no doubt that soil-structure interaction (SSI) effects could significantly impact on the response of structures under seismic loads, this phenomenon is often neglected in control of structures. In the present research, the simple adaptive control (SAC) algorithm is utilized in conjunction with the magnetorheological (MR) damper to control the responses of a nonlinear structure based on soft soil analytically and the results are compared with passive-on and passive-off states. As the prototype structure is from an experimental test, a reliable framework is established by validating the accuracy of the structural model. The SSI effects are investigated from several aspects such as effects on control forces and performance of SAC in control of soil-structure systems. In addition to using conventional evaluation criteria in control problems, fragility analysis is carried out to study the structural behavior and SSI effects in-depth. It is observed that the SAC algorithm is capable of controlling the responses of structures and the outcomes are satisfying comparing to the passive approaches. The results show that neglecting SSI could completely underestimate damage to controlled structures especially structures based on soft soil and it will lead to error in the first estimation of control forces during design.