Causal semiactive control of seismic response

A challenge in the use of semiactive dampers for the earthquake response reduction is the development of implementable control algorithms. Exact optimal control resulting from the numerical solution to Euler-Lagrange equations requires a priori knowledge of earthquake in the control interval, which is not possible. This paper proposes a causal sub-optimal implementable control to reduce the earthquake response using an inherently nonlinear controllable fluid damper. The proposed method is basically based on the prediction of the near-future ground accelerations using maximum-entropy method. The earthquake response of low-rise, two degree of freedom (dof) base isolated structure is investigated for the proposed causal sub-optimal control and the resulting performance is compared to the exact optimal control and the uncontrolled case. The results show that the proposed control is promising in protecting the earthquake-excited buildings.