Performance evaluation of robust controllers in earthquake structural dynamics problems with large hysteretic nonlinearities

Hybrid passive-active systems for controlling building seismic response offer the promise of combining the best features of each to achieve superior performance. Analytical investigations of building hybrid control systems designed to combine robust active control systems with passive damping provided by structural hysteresis are described. The passive control forces were introduced through hysteretic interaction between heavy architectural cladding and the supporting structure, while the active control forces were assumed to be generated by an active tendon system. Results presented for a case study structure show that the hybrid control system was more effective in reducing peak drift compared with the cases of either the passive or active systems acting alone. Moreover, it is shown that a practical robust control system of reduced order can be designed with sufficient and robust stability to tolerate as much as a 50% change in the nominal structural stiffness. At the same time, the presence of passive damping yielded reduction in peak force requirements for the active system